1. Is it possible to specify a displacement and then have STAAD analyze a frame to give me a corresponding load (the load that would have been required to produce that displacement)?
2. I am applying a UBC seismic load on a bridge. The analysis engine reports an error message which says that:EITHER NA OR NV FACTOR HAS NOT BEEN SPECIFIED WHILE SEISMIC ZONE HAS BEEN SPECIFIED AS 4.
3. I would like to create a REPEAT LOAD case whose constituent load cases are themselves REPEAT LOAD cases. Is this allowed?
4. After determining the lateral loads using Staad UBC seismic analysis in a first file, I note down the lateral loads computed at each joint. In a second separate file with the same frame model, I apply the lateral loads from the first file combining them with the gravity loads and perform the analysis. I consider this procedure of mine very tedious in case of a 3D high rise building most specifically in view of the first file. Is there any shorter procedure for this? Please take note that I am using the Command File Editor.
5. I am trying to analyse a structure which consists of a large dia pipe supported at discrete points. I am unable to get STAAD to analyse this for UBC loads.
6. I am modelling a steel building consisting of columns and beams. The floor slab is a non-structural entity which, though capable of carrying the loads acting on itself, is not meant to be an integral part of the framing system. It merely transmits the load to the beam-column grid.  There are uniform area loads on the floor (think of the load as wooden pallets supporting boxes of paper). Since the slab is not part of the structural model, is there a way to tell the program to transmit the load to the beams without manually figuring out the beam loads on my own?
7. When does one use FLOOR LOAD and when does one use ELEMENT LOAD?
8. What is the difference between the LOAD COMB & REPEAT LOAD commands?
9. I am modelling an elevated silo which will be used for storing grain. The columns which support the structure are modelled as members and the walls of the silo (containment part of the structure) are modelled using plate elements. The silo has vertical and sloping walls. The loads on the structure consist of the weight of the grain contained in the silo. What is the best method for applying the load when the silo is full of grain? As pressure loads on the inside? How should the load be applied on the sloping walls?
10. I modeled a curved beam using cylindrical coordinates and tried to run a moving load over the curved beam. STAAD.Pro is not allowing me to do this. Why?
11. What is the significance of the Rw Value in the UBC code?
12. How is the wind load calculated/generated for a structure in STAAD.Pro ? What is the exposure factor calculated and how is it calculated? In 2002, I hear you can now define your own "panels"? What does this mean?
13. I am using the moving load generation. The truck that I am specifying is so wide (dimension perpendicular to direction of traffic) that within the width of one lane of traffic, there are 3 or more parallel beams along the direction of traffic. How does STAAD determine how the truck load should be converted to beam loads?
14. For moving load generation, does STAAD provide the location of all the moving point loads in terms of member number and distance from the start of the member?
15. How does STAAD consider the moving load over the beams if the load is not applied over a beam exactly?
16. If we have a wind load on a bracing system (perpendicular to the bracing plane), can we apply the wind loading directly to the brace as a uniform load instead of resolving the force into point loads? How does Staad handle this type of loading on members that are declared trusses?
17. I am using the moving load generation facility to generate a set of load cases for a truck moving on a bridge. Can STAAD provide the support reactions for the critical position that produces the maximum effects on the system flooring?
18. I have some distributed loads on some members of the model. I would like to consider the weights due to these loads in the base shear calculation for UBC load generation. Can you explain the process for doing this?
19. What is JOINT WEIGHT? I'm trying to learn how to use the seismic load generator and I don't see anything explaining what JOINT WEIGHT is or what it is used for.
20. How do I get STAAD to automatically combine static load cases with load cases generated using the MOVING LOAD generation facility?
21. How to calculate the temperature parameter f1 and f2  for applying temperature load on the
    structure?
22. I have multiple structures modeled in STAAD with varying heights and I want to use the Automatic Seismic Load Generation in STAAD. Can STAAD still properly distribute the seismic forces even though my structures are disjointed ?
23. I defined dead and live loads as reference load cases and I used these cases for specifying seismic weights as part of my seismic load definition. Do I have to re-define the dead loads and live loads as part of the seismic load case ?
24. Can STAAD automatically calculate the seismic forces both in horizontal and vertical direction required by ASCE as shown next E = (Rho) x QE (+/-) 0.2 x SDS x D

1. Is it possible to specify a displacement and then have STAAD analyze a frame to give me a corresponding load (the load that would have been required to produce that displacement)?

You first need to know the pattern or arrangement of the loading which will eventually cause the displacement you wish to see. This is because, there can be millions of loading arrangements which cause that amount of displacement at that node, so one needs to have an idea of which of those patterns is the one that one wants. By pattern, we are talking of details like, is the load going to consist of concentrated forces at nodes, or distributed and trapezoidal loads on members, or pressures on plates, etc. For example, any of these loads will cause a certain amount of displacement at a node along a certain direction.

So, a unit load analysis would be the best approach for solving this kind of a problem. That means, all the components of the loading pattern would be represented by unit loads. Let us say that by applying a member load of 100 pounds/ft, you get 0.4 inches of displacement along global X at node 43. So, if the final desired displacement at node 43 along X is say, 1.2 inches, the applied load should be simply (1.2/0.4)*100 = 300 pounds/ft.

2. I am applying a UBC seismic load on a bridge. The analysis engine reports an error message which says that:

EITHER NA OR NV FACTOR HAS NOT BEEN SPECIFIED

WHILE SEISMIC ZONE HAS BEEN SPECIFIED AS 4.

This is due to the fact that, for your model, STAAD looks at the data under the DEFINE UBC LOAD command and concludes that you intend to analyse the structure per the UBC 1997 code. It then checks whether all the required parameters have been specified for that code, and detects that NA and NV are missing. You perhaps have an input similar to the one below :

DEFINE UBC LOAD
ZONE 0.4 I 1 RWX 12 RWZ 12 STYP 1.2 PX 0.2626 PZ 0.2626

For Zone 4, Na and Nv are two of the fundamental parameters necessary to calculate the base shear. If you look at Tables 16-Q and 16-R on pages 2-34 & 2-35 of the UBC 1997 code, you will find that for Zone 4, the coefficients Ca and Cv are dependent on Na and Nv.

So, specify the NA and NV parameters, so that the commands look similar to the one below :

DEFINE UBC LOAD
ZONE 0.4 I 1 RWX 12 RWZ 12 STYP 1.2 NA 1.6 NV 1.6 PX 0.2626 PZ 0.2626

3. I would like to create a REPEAT LOAD case whose constituent load cases are themselves REPEAT LOAD cases. Is this allowed?

You can do this if you have STAAD.Pro version 2002 or later. An example of this is shown below.

LOADING 1
SELFWEIGHT Y -1.0

LOAD 2
REPEAT LOAD
1 1.0
JOINT LOAD
4 5 FY -15. ; 11 FY -35.

LOAD 3
REPEAT LOAD
2 1.0
MEMB LOAD
8 TO 13 UNI Y -0.9 ; 6 UNI GY -1.2

LOAD 4
SELFWEIGHT Y -1.0
JOINT LOAD
4 5 FY -15. ; 11 FY -35.
MEMB LOAD
8 TO 13 UNI Y -0.9 ; 6 UNI GY -1.2

PERF ANALY
LOAD LIST 3 4
PRINT *** RES
FINISH

In the above example, load case 3 repeats load case 2, which in turn repeats load case 1.

4. After determining the lateral loads using Staad UBC seismic analysis in a first file, I note down the lateral loads computed at each joint. In a second separate file with the same frame model, I apply the lateral loads from the first file combining them with the gravity loads and perform the analysis. I consider this procedure of mine very tedious in case of a 3D high rise building most specifically in view of the first file. Is there any shorter procedure for this? Please take note that I am using the Command File Editor.

There is absolutely no need for you to take the lateral load data from the output of the first file, and insert it as input into the second file. In STAAD, once the lateral loads due to UBC or IBC are generated, they are automatically available for combining with gravity loads, or any other loads for that matter. Consequently, there are 2 ways in which this combination can be achieved, and each is demonstrated below :

Method 1 :
Generate the lateral load in one load case. Specify the gravity load in another load case. Then, combine the two in a load combination case.

LOAD 1 - GENERATE LATERAL LOADS DUE TO UBC ALONG X
UBC X 1.0

LOAD 2 - SPECIFY GRAVITY LOADS
SELFWEIGHT Y -1.0
MEMBER LOAD
1 TO 25 UNI GY -1.2
JOINT LOAD
10 39 FY -10.0

LOAD COMBINATION 3 - COMBINE THE LATERAL AND GRAVITY LOADS IN ONE CASE
1 1.0 2 1.0

Method 2 :
Create a single load case in which the lateral forces are generated, and gravity loads are specified.

LOAD 1 - LATERAL LOADS + GRAVITY LOADS
UBC X 1.0
SELFWEIGHT Y -1.0
MEMBER LOAD
1 TO 25 UNI GY -1.2
JOINT LOAD
10 39 FY -10.0

5. I am trying to analyse a structure which consists of a large dia pipe supported at discrete points. I am unable to get STAAD to analyse this for UBC loads.

When the UBC committee came up with the recommendations for analysing structures subjected to earthquakes, the type of structures they had in mind were conventional style buildings where the base of the model, namely, the points where the supports are located is at the lowest elevation with respect to the rest of the model.

If you look at the UBC procedure, it involves computation of the base shear, which then has to be distributed over the height of the building, so that one can then calculate the inter-story shears. A certain amount of the weight gets lumped at the highest point of the building, and the rest gets distributed along the height. In other words, the principle is that a mass at any height of the building is subjected to an acceleration and the force caused by the acceleration is represented by a concentrated force where the mass is located. The summation of all such forces at a given floor cause the columns beneath that floor to be subjected to a shear force.

When you talk of a model like a pipe which is defined as line members attached to several collinear nodes, all of which are at the same elevation, the UBC rules become impossible to apply. The fact is, to analyse your structure for seismic effects, you do not even need the elaborate procedure of the UBC code. You can take the selfweight, and any imposed loads on the pipe, and apply them along a horizontal direction like X or Z with a factor, and you will get what is normally expected in a seismic analysis.

So, you just have to have

LOAD 2
SELF X n

where n is a number like 1.5, which represents that there is a net force of 1.5 times the weight of the structure acting along the X direction due to an earthquake. For better handling of the distributed loads, you might want to consider defining several nodes along the length of the pipe, between supports.

6. I am modelling a steel building consisting of columns and beams. The floor slab is a non-structural entity which, though capable of carrying the loads acting on itself, is not meant to be an integral part of the framing system. It merely transmits the load to the beam-column grid.  There are uniform area loads on the floor (think of the load as wooden pallets supporting boxes of paper). Since the slab is not part of the structural model, is there a way to tell the program to transmit the load to the beams without manually figuring out the beam loads on my own?

STAAD's FLOOR LOAD option is ideally suited for such cases. This is a facility where you specify the load as a pressure, and the program converts the pressure to individual beam loads. Thus, the input required from the user is very simple - load intensity in the form of pressure, and the region of the structure in terms of X, Y and Z coordinates in space, of the area over which the pressure acts.

In the process of converting the pressure to beam loads, STAAD will consider the empty space between criss-crossing beams (in plan view) to be panels, similar to the squares of a chess board. The load on each panel is then tranferred to beams surrounding the panel, using a triangular or trapezoidal load distribution method.

Additional information on this facility is available in example problem 15 in the examples manual, and section 5.32.4 in the STAAD.Pro Technical Reference manual.

7. When does one use FLOOR LOAD and when does one use ELEMENT LOAD?

When modelling a grid system made up of horziontal beams and the slabs which span between the beams, we have found that there are 2 approaches that users take :

1) They model the beams only, and do not include the slabs in the model. However, they take into account the large inplane stiffness of the slab by using the master-slave relationship to tie together the nodes of the deck so that a rigid diaphragm effect is simulated for the horizontal plane at the slab level.

2) They model the slabs along with the beams. The slabs are modelled using plate elements.

The question that arises is, how does one account for the distributed loading (load per area of floor) which is present on top of the slab?

If you model the structure using method (1), the load can be assumed to be transferred directly on to the beams. The slab-beam grillage is assumed to be made up of a number of panels, similar to the squares of a chess board. The load on each panel is then tranferred to beams surrounding the panel, using a triangular or trapezoidal load distribution method. You can do this in STAAD by defining the load intensity in the FLOOR LOAD command. In other words, the pressure load on the slabs (which are not included in the model) are converted to individual beam loads by utilizing the FLOOR LOAD facility.

In method (2), the fact that the slab is part of the model makes it very easy to handle the load. The load can be applied on individual elements using the ELEMENT LOAD facility. The connectivity between the beams and elements ensures that the load will flow from the plates to the beams through the columns to the supports.

8. What is the difference between the LOAD COMB & REPEAT LOAD commands?

The difference lies in the way STAAD goes about calculating the results - joint displacements, member forces and support reactions. For a load combination case, STAAD simply ALGEBRAICALLY COMBINES THE RESULTS of the component cases after factoring them. In other words, for example, in order to obtain the results of load 10, it has no need to know what exactly is it that constitutes load cases 3, 4 and 5. It just needs to know what the results of those cases are. Thus, the structure is NOT actually analysed for a combination load case. With a REPEAT LOAD case however, the procedure followed is that which occurs for any other primary load case. A load vector {P} is first created, and later, that load vector gets pre-multiplied by the inverted stiffness matrix.

9. I am modelling an elevated silo which will be used for storing grain. The columns which support the structure are modelled as members and the walls of the silo (containment part of the structure) are modelled using plate elements. The silo has vertical and sloping walls. The loads on the structure consist of the weight of the grain contained in the silo. What is the best method for applying the load when the silo is full of grain? As pressure loads on the inside? How should the load be applied on the sloping walls?

There are 2 segments of the tank which have to be individually considered for application of the load.

The vertical walls
------------------

The material in the tank, especially if it is a fluid, will exert a lateral pressure on the vertical walls of the tank. This pressure load can be applied on the tank using the ELEMENT PRESSURE load facility. You can use one of 2 options to do this.

a) A uniform pressure. If you take any individual element on the wall, if you know the pressure intensity at the top edge, and the pressure intensity at the bottom edge, the average of these 2 intensities can be applied as a constant pressure on the entire surface of the element, as in the following example :

45 PRESSURE -3.5

Since the load is along the local Z axis of the element, you do not have to specify the axis name in the above command since local Z is the default for the axis. The load value must be accompanied by the proper sign (positive or negative) which accounts for whether the load acts along or opposite to the direction of the local Z axis.

b) A trapezoidally varying pressure.

In case (a) above, we decided to take the average of the pressures at the top and bottom edges, and thus obtain a uniform pressure. However, this is not absolutely necessary. The load can be applied as a trapezoidal load, in which case, the TRAP option is used and the intensities at the top and bottom edges must be specified. An example of that is

45 PRESSURE TRAP Y -4.5 -2.5

In this example, it is assumed that the local Y axis of element 45 is along the vertical direction, and thus the trapezoidal variation is along the local Y. The load itself acts perpendicular to the surface of the element, and hence along local Z. If local Y is in the same sense as global Y, -4.5 indicates the intensity at the lower edge, and -2.5 indicates the intensity at the upper edge.

If the vertical wall has many divisions along the vertical direction, there will be several "horizontal rings" of elements. Every element contained in a ring has the same intensity at its top and bottom edge. That means, the top & bottom intensity for each of those rings will have to be manually calculated. There is a facility in the STAAD.Pro GUI to simplify this task. From the top of the screen, select Commands - Loading - Load Commands - Element - Hydrostatic Trapezoidal, and provide the intensities at the top and bottom edges of the vertical wall. The program will use the linear interpolation method to find the intensity at each intermediate division, and then create the individual element TRAPEZOIDAL loads.

The sloping walls
-----------------

The load on the elements which make up these walls is derived from the weight of the column of material directly above these elements, and acts along the global vertical downward direction. Since the element TRAP load facility that is available in STAAD allows a load to be applied only along the local Z axis, and since local Z is not parallel to any of the global directions, the TRAP load option cannot be used here. Hence, one will have to apply these as uniform pressure loads, the value of which has to be calculated for each sloping element as the average of the intensities at the 4 nodes of that element. There is no generation facility currently available in the program to automate this task.

10. I modeled a curved beam using cylindrical coordinates and tried to run a moving load over the curved beam. STAAD.Pro is not allowing me to do this. Why?

Moving load on curved beams is not supported by the DEFINE MOVING LOAD command in STAAD.Pro. The STAAD moving load generator assumes:
1)All loads are acting in the negative global vertical (Y or Z) direction. The user is advised to set up the structure model accordingly.
2)Resultant direction of movement is determined from the X, Y and Z increments of movements as provided by the user.

However, STAAD.beava, an automated bridge load generator, can handle moving loads for curved or custom-defined bridge decks with beams and plates. It also generates a 3D influence surface based on displacements, support reactions, beam forces or plate stresses for any point on the bridge. The critical loading patterns and critical vehicle position will be identified as well. STAAD.beava is an integrated module in the STAAD.Pro environment.

11. What is the significance of the Rw Value in the UBC code?

The UBC 1997 code defines Rw as a Numerical Coefficient representative of the inherent overstrength and global ductility capacity of lateral-force resisting systems.

It is to be used in the equation for computing base shear. Its values are dependent on the type of lateral-force resisting system in the building, such as whether the system is a Light-framed wall with shear panels or Shear wall made of concrete or a special moment resisting frame, etc.

Values of Rw are listed in Tables 16-N and 16-P of the UBC 1994 and 1997 codes.

12. How is the wind load calculated/generated for a structure in STAAD.Pro ? What is the exposure factor calculated and how is it calculated? In 2002, I hear you can now define your own "panels"? What does this mean?

The DEFINE WIND LOAD command may be used to define the parameters for automatic generation of wind loads on the structure. The user needs to define the intensity and corresponding heights along with the exposure factors. If the exposure factor is not defined, the program takes the default value as 1.0.

A value of 1.0 means that the wind force may be applied on the full influence area associated with the joints if they are also exposed to the wind load direction.
All loads and heights are in the current unit system. In the list of intensities, the first value of intensity (p1) acts from the ground level up to the first height. The second intensity (p2) acts in the global vertical direction between the first two heights (h1 and h2) and so on. The program assumes that the ground level has the lowest global vertical coordinate of any joint entered for the structure.

The exposure factor (e) is the fraction of the influence area associated with the joint(s) on which the load may act if it is also exposed to the wind load. Total load on a particular joint is calculated as follows.

JOINT LOAD = (Exposure Factor) x (Influence Area) x (Wind Intensity).

Exposure factor (User specified) = (Fraction of Influence Area) x (influence width for joint).

In STAAD.Pro 2002, the built-in wind load generation facility has been enhanced to allow the user to specify the actual panels of the building which are exposed to the wind. This user-level control will now allow the user to obtain a more accurate distribution of wind forces, especially when the exposed surface of the building lies in several vertical zones, each reset from the one below or the one above, in terms of the direction of wind force. Further, the basic algorithm for detecting the shape of the panels and the amount of load which should be calculated for the panel corners too has undergone significant improvements. The parameters for definition of the wind load types are described in Section 5.31.3 of the STAAD.PRO Technical Reference Manual. The relevant extracts from Section 5.32.12 of the STAAD.Pro Technical Reference Manual, where the method for applying wind loading in the form of a data in load cases has been explained, is provided below. Note that areas bounded by beam members (and ground), and exposed to the wind, are used to define loaded areas (plates and solids are ignored). The loads generated are applied only at the joints at vertices of the bounded areas. For example, in the following set of commands:

DEFINE WIND LOAD
TYPE 1
INTENSITY 0.1 0.12 HEIGHT 100 200
EXP 0.6 JOI 1 TO 25 BY 7 29 TO 37 BY 4 22 23
TYPE 2
INT 0.1 0.12 HEIGHT 100 900
EXP 0.3 YR 0 500
LOAD 1
SELF Y -1.0
LOAD 2
WIND LOAD Z 1.2 TYPE 2 ZR 10 11
LOAD 3
WIND LOAD X TYPE 1 XR 7 8

A minus sign indicates that suction occurs on the other side of the selected structure. If all of the members are selected and X (or Z) is used and the factor is positive, then the exposed surfaces facing in the -x (or -z) direction will be loaded in the positive x (or z) direction (normal wind in positive direction). If X and a negative factor is used, then the exposed surfaces facing in the +x direction will be loaded in the negative x direction (normal wind in negative direction). [If -X is entered and a negative factor, then the exposed surfaces facing in the -x direction will be loaded in the negative x direction (suction). If -X is entered and a positive factor, then the exposed surfaces facing in the +x direction will be loaded in the positive x direction (suction).] A member list or a range of coordinate values (in global system) may be used. All members which have both end coordinates within the range are assumed to be candidates for defining a surface which may be loaded if the surface is exposed to the wind. The loading will be in the form of joint loads (not member loads). 1, 2 or 3 ranges can be entered to form a "layer", "tube" or "box" for selecting members in the combined ranges. Use ranges to speed up the calculations on larger models.

It is advisable not to use the SET Z UP command in a model with wind load. A closed surface is generated by the program based on the members in the ranges above and their end joints. The area within this closed surface is determined and the share of this area (influence area) for each node in the list is then calculated. The individual bounded areas must be planar surfaces, to a close tolerance, or they will not be loaded. Hence, one should make sure that the members/joints that are exposed to the wind make up a closed surface (ground may form an edge of the closed surface). Without a proper closed surface, the area calculated for the region may be indeterminate and the joint force values may be erroneous. Consequently, the number of exposed joints should be at least 3.

13. I am using the moving load generation. The truck that I am specifying is so wide (dimension perpendicular to direction of traffic) that within the width of one lane of traffic, there are 3 or more parallel beams along the direction of traffic. How does STAAD determine how the truck load should be converted to beam loads?

Based on the data you provide under the DEFINE MOVING LOAD command, each truck is treated as a set of axles. If the WIDTH option is NOT specified, each axle is assumed to be comprised of 1 tire. If the WIDTH option is specified, each axle is assumed to be comprised of 2 tires.

The program looks at each tire independently. For any given tire, it looks for one longitudinal beam to the left of the tire, and another longitudinal beam to the right of the tire. Then it distributes the tire weight on those 2 beams as though the tire is located on a simply supported cross beam that spans the two longitudinal members on either side.

Thus, even if a lane spans across 3 longitudinal beams or for that matter several beams, the above approach ensures that the tire weights get properly applied on the correct set of beams as concentrated member loads.

You can get a listing of these concentrated member loads by using the command:
PERFORM ANALYSIS PRINT LOAD DATA

14. For moving load generation, does STAAD provide the location of all the moving point loads in terms of member number and distance from the start of the member?

Yes. Please use the PRINT LOAD DATA option with your PERFORM ANALYSIS command and you will get the information in your output file.

15. How does STAAD consider the moving load over the beams if the load is not applied over a beam exactly?

If a wheel falls inside a panel composed of beams on either side of the wheel running parallel to the direction of movement of the vehicle, the load is distributed on the 2 beams as simply supported reactions. Hence, if the wheel load is 10 kips, and if the distance from the wheel to the beam on the left is 7 ft, and the distance to the beam on the right is 3 ft, the beam on the left gets a 3 kip load, and the beam on the right gets a 7 kip load.

16. If we have a wind load on a bracing system (perpendicular to the bracing plane), can we apply the wind loading directly to the brace as a uniform load instead of resolving the force into point loads? How does Staad handle this type of loading on members that are declared trusses?

If a transverse load such as a uniform distributed load or a concentrated force is applied on a truss member, STAAD converts it to the equivalent concentrated shears at the 2 ends of the member. The member end force output will show them as shears on the member under the output terms SHEAR-Y or SHEAR-Z depending on the local axis direction the load is applied in.

However, if you determine the equivalent end shears and apply them as joint loads instead, and not as a member load, the truss members at that node will not experience any shear force due to that load.

17. I am using the moving load generation facility to generate a set of load cases for a truck moving on a bridge. Can STAAD provide the support reactions for the critical position that produces the maximum effects on the system flooring?

This would require that the support reactions for all generated load cases be produced in a report form sorted in a descending order based upon the specific support reaction criteria we are interested in, such as the FY force, or the MZ moment.

To get this report, first run the analysis. Go to the Post processing mode. Select the support node(s) at which you want the information you are seeking. From the top of the screen, select Report | Support Reactions. In the dialog box that comes up, select the degree of freedom (FY, MZ, etc.) which should be used as the criteria for sorting. Set the sorting order (high to low or low to high). From the loading tab, select the load cases that you want considered. Click on OK. A report of the results will be displayed in tabular form.

18. I have some distributed loads on some members of the model. I would like to consider the weights due to these loads in the base shear calculation for UBC load generation. Can you explain the process for doing this?

When analysing a structure for UBC loads, there 2 stages in the input. The first stage is the one where one defines data such as the various parameters (zone factor, importance factor, soil structure interaction factor, etc.) as well as the weights. In terms of the STAAD command language, it is initiated using the DEFINE UBC LOAD command, and an example for this may be found in Example 14 of the STAAD.Pro Examples manual.

Graphically, one may assign the data in the following manner.

Select the beam or beams you want to assign the distributed weights to. Next, from the top of the screen, select Commands | Loading | Define Load | Seismic Load. In the Parameters tab, select the type, and enter the relevant
values for the parameters. Press the "Save" button. A new tab called "Weights" should come up. Press the "Member Weight" button. For the loading type, choose UNI, enter the distributed weight value, distances to where the load starts and the load ends, and press "OK". Press the "Assign" button to actually assign them to the selected members. Finally, press the "Close" button.

19. What is JOINT WEIGHT? I'm trying to learn how to use the seismic load generator and I don't see anything explaining what JOINT WEIGHT is or what it is used for.

In the block of commands which fall under the DEFINE UBC LOAD heading or any of the other ones like AIJ ,1893, etc., the weight data which goes into the calculation of the total weight consists of :

SELFWEIGHT

MEMBER WEIGHT

JOINT WEIGHT

If at any of the joints of the structure, there are any weights which you want included in the total weight calculation, you specify them using the JOINT WEIGHT option.

20. How do I get STAAD to automatically combine static load cases with load cases generated using the MOVING LOAD generation facility?

You should use the option called ADD LOAD along with the LOAD GENERATION command.

Shown below is an example:

DEFINE MOVING LOAD
TYPE 1 LOAD 20. 20. 10. DISTANCE 10. 5. WIDTH 10.
LOAD 1 STATIC LOAD
SELF Y -1.0

* GENERATE MOVING LOADS AND ADD THE SELFWEIGHT
* LOAD TO EACH GENERATED LOAD CASE

LOAD GENERATION 10 ADD LOAD 1
TYPE 1 7.5 0. 0. ZI 10.
PERFORM ANALYSIS PRINT LOAD DATA

21. How to calculate the temperature parameter f1 and f2  for applying temperature load on the
structure?

You have to know three temperatures :
 
1) the stress-free temperature, which is the temperature that the structure was at when it was constructed or installed.  Call it A.
 
2) The temperature of the top fiber (the fiber that is farthest along the positive direction of the local Z axis of elements and local Y axis for beam). Call it B.
 
3) The temperature of the bottom fiber (the fiber that is farthest along the negative direction of the local Z axis of element and local Y axis for beam). Call it C.
 
When you specify the temperature load, the command is
member-list TEMPERATURE f1 f2
where
 
f1 = (B+C)/2 - A
 
f2 = B-C
 
f1 is the temperature that causes axial elongation / shrinkage along the longitudinal axis (local X of the member, and, local X and Y axes for the plate element).
 
 f2 is the temperature responsible for inducing bending in the member and element.
 
Also, refer to article 5.32.6 of the Technical Reference Manual of Staad.pro

22. I have multiple structures modeled in STAAD with varying heights and I want to use the Automatic Seismic Load Generation in STAAD. Can STAAD still properly distribute the seismic forces even though my structures are disjointed ?

STAAD.Pro Seismic Load Generation should not be used in this case. If the structures are independent of each other, you should have 3 separate models and do seismic load generation on each model separately.

23. I defined dead and live loads as reference load cases and I used these cases for specifying seismic weights as part of my seismic load definition. Do I have to re-define the dead loads and live loads as part of the seismic load case ?

Related question : I defined dead loads, live loads for seismic weight calculation as part of my seismic load definition. Do I again need to specify the dead and live loads as part of the seismic load cases ?

No you do not need to. Once the seismic weight is defined ( either through reference load or through the various seismic weight definition options ) as part of the seismic load definition, the software is able to figure out the total seismic weight. You do not need to redefine. Doing so would apply these as additional loads to the ones already defined. 

24. Can STAAD automatically calculate the seismic forces both in horizontal and vertical direction required by ASCE as shown next 

E = (Rho) x Q_E (+/-) 0.2 x S_DS x D

The seismic load generation in STAAD only calculates the horizontal portion Q_E. The factors like Rho or the vertical effect factors like 0.2SDS has to be calculated manually and applied as factors to the appropriate loads when defining load combinations. 

See Also

Product TechNotes and FAQs

Structural Product TechNotes And FAQs

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

Comments or Corrections?

Bentley's Technical Support Group requests that you please confine any comments you have on this Wiki entry to this "Comments or Corrections?" section. THANK YOU!

1. In the output file, I see the following message ** WARNING ** A SOFT MATERIAL WITH (1.0 / 1.750E+01) TIMES THE STIFFNESS OF CONCRETE ENTERED. PLEASE CHECK.
2. In STAAD.Pro, you are providing Steel, Concrete and Aluminum as standard materials with built-in default values. Why isn't timber included? I am looking for the Modulus of Elasticity and Density of Douglas Fir.
3. I am analysing a plane frame. I specify a prismatic section with IX. The analysis stops with the error message that I need to specify IZ. What is the need to specify IZ?
4. What is the purpose of the "member release" command? What is the basis for the terms MX, MY and MZ in this command?
5. Can you please explain the concept behind member offsets?
6. Shouldn't there be a way to set the MEMBER TENSION attribute once for the model and have the program always look back on that line for the list of members which have been assigned this property? Obviously, the same goes for MEMBER TRUSS.
7. The STAAD graphical interface is showing a steel column in my model in an incorrect orientation. I have checked my input file (and also by double clicking on the actual member) and all of my columns consistently start at the lower node and go in the +y direction, all have a beta of 0, and all have the same member property. I have the exact same data for this graphically-incorrect column as the one below it that shows up the correct orientation. Yet another column shows a slightly skewed column orientation as if I had assigned it something other than 0 or 90 degrees, and I know for a fact that I haven't done this. 
8. I have a beam member for which I have assigned a single angle from the American steel table. When I look at the member properties output for that member, the values that STAAD reports for moments of inertia Iz and Iy do not match the values I see in the AISC steel publication for that angle section.
9. I understand that one should use the REPEAT LOAD command and not the LOAD COMBINATION command when analysing a model for cases where the MEMBER TENSION or MEMBER COMPRESSION command has been used. Talking about load combinations, in Section 5.35 of the STAAD Technical Reference Manual, notes Item (2) mentions that the LOAD COMBINATION command is inappropriate for a PDELTA analysis, and that one should use REPEAT LOADs instead. This appears to be true for NON-LINEAR analysis also. Why? 

1. In the output file, I see the following message

** WARNING ** A SOFT MATERIAL WITH (1.0 / 1.750E+01) TIMES THE STIFFNESS OF
CONCRETE ENTERED. PLEASE CHECK.

Please explain to me in plain English what StaadPro is trying to tell me.

STAAD checks to see if the E (Modulus of Elasticity) assigned to members and elements is comparable to the values of steel, aluminum, concrete or timber. If it falls below or above the range of these materials, warning messages similar to the one you encountered are displayed. This is done to notify the user in case he/she is not aware of this fact, or if he/she may have specified the value in an incorrect unit system.

If you believe that your E is specified correctly, you may ignore the message. Else, correct the number.

2. In STAAD.Pro, you are providing Steel, Concrete and Aluminum as standard materials with built-in default values. Why isn't timber included? I am looking for the Modulus of Elasticity and Density of Douglas Fir.

Unlike the 3 materials mentioned in your question, timber comes in several varieties, with each variety having its own unique set of material properties. Douglas Fir alone comes in several varieties, as explained below.

The American Wood Council and the American Forest & Paper Association publish a document called the "Supplement NDS for Wood Construction", 1997 edition. It provides design values for structural sawn lumber and glued laminated timber. There is also a category called Visually Graded Decking.

Under each category, Douglas Fir comes in various species or combination of species. Under each species, there are various commercial grades. Each of those grades have a unique value of E, ranging from 1000 ksi to 1900 ksi. If the category, species, and commercial grade is known, the E value can be read from the tables in this document.

The American Wood Council and the American Forest & Paper Association also publish a document called the "ASD Manual for Engineered Wood Construction". In the 1999 edition of this document, Table 8A, page 15 contains the specific gravity of Douglas Fir as ranging from 0.46 to 0.5.

3. I am analysing a plane frame. I specify a prismatic section with IX. The analysis stops with the error message that I need to specify IZ. What is the need to specify IZ?

For plane frames with no beta angle, what is needed is IZ, not IX. IX is the torsion constant. IZ is the moment of inertia about the Z axis. Members of a plane frame with a beta angle of zero will bend about the Z axis, which explains the need for IZ. They are not prone to twisting, and that is why IX is not needed.

Table 1.1 from the Technical Reference manual, which shows the properties required for various types of structures, is reproduced below.

4. What is the purpose of the "member release" command? What is the basis for the terms MX, MY and MZ in this command?

By default, STAAD assumes the connection between any 2 members to be fully capable of transmitting all 3 forces and all 3 moments from one member to the other. This is usually achieved in practice by moment resistant connections, such as between a concrete beam and a concrete column which are monolithically cast.

If you want the connection to be of the type which does not permit one or more forces/moments to be transmitted, use member releases. A shear connection is such an example. The degrees of freedom FX through MZ that you release are based on the local axis of the member at whose end the release is specified.

See section 5.22.1 and the figures in Section 1.19 of the STAAD.Pro Technical Reference manual for additional information.

5. Can you please explain the concept behind member offsets?  

 When creating a model consisting of beams and columns, generally, the START or END face of the member is assumed to be located at the nodal point. In other words, the distance from the respective node to the start or end face of the member is treated as zero. Thus, for example, if member 47 is defined as being connected between nodes 12 and 13, then, the start face of the member is located at node 12, and the end face at node 13.

 This assumption may not always reflect the true physical condition on the structure. For example, when a beam meets a column, the common node between the beam and column is usually defined as being at the shear center (centerline for symmetrically shaped) of the column.

But, physically, the start face of the beam is not at that node, but at half the column depth away from the node. One may choose to ignore this "shift" if the column depth is negligible in comparison to the span of the beam. However, if one wishes to take advantage of the high stiffness that the half-depth region of the column offers, he/she may consider this using the member offset command.

The member offset is a way of declaring that the region, whose length is defined by the offset, is a rigid zone. Hence, if the offset values in X, Y and Z coordinates are a, b and c, the length of that region is d=sqrt(a*a + b*b + c*c). The face of the member is then assumed to be "d" away from the node.

The member end forces that STAAD reports are at the face of the member, not at the node, when an offset is specified. If the offset is applied at the base of a column, then the member end force may not be equal in magnitude to the corresponding support reaction terms. If one is interested in checking static equilibrium based on the free body diagram at that support, the member end forces must be transferred from the member face to the support node taking into consideration the rigid link defined by the offset. 

6. Shouldn't there be a way to set the MEMBER TENSION attribute once for the model and have the program always look back on that line for the list of members which have been assigned this property? Obviously, the same goes for MEMBER TRUSS.

In fact, that is exactly what STAAD is designed to do already. There is no need to keep re-specifying the MEMBER TENSION command, unless you want to specify a different list of such members. So, specify it once for the first analysis, and you don't have to specify it again. Same goes for the MEMBER TRUSS command.

7. The STAAD graphical interface is showing a steel column in my model in an incorrect orientation. I have checked my input file (and also by double clicking on the actual member) and all of my columns consistently start at the lower node and go in the +y direction, all have a beta of 0, and all have the same member property. I have the exact same data for this graphically-incorrect column as the one below it that shows up the correct orientation. Yet another column shows a slightly skewed column orientation as if I had assigned it something other than 0 or 90 degrees, and I know for a fact that I haven't done this.

a - Is the graphical interface a reliable representation of my input?

b - If yes, can you think of some other possible sources of this particular error?

If you look at the coordinates of the columns which appear to be oriented in the wrong way, chances are that you will find the Z coordinate of the 2 ends to be different by a very minute value, such as 0.001. For example, one end may have a Z value of 5.999 while the other end may be at 6.000. If so, you could do the following to correct it. Select the Geometry-Beam page along the left side of the screen, and it will display the node coordinates in the tables on the right hand side. In those tables, make the necessary correction so both ends of the column have the same Z coordinate.

The potential cause of this difference in coordinates is the following. The program has something called a Base Unit system. You can find this by starting the program, and before opening any file, go to the File menu, select Configure, and see if it says "English" or "Metric". If the model you are going to create is in Metres and KNs, you ought to have the base units in Metric. If the model you are going to create is in Feet and Kips, you ought to have the base units in English. Mixing unit systems causes the program to perform internal unit conversions which can result in loss of digits because the built-in conversion factors have only upto 8 digits of accuracy.

In fututure versions of STAAD, there will be a feature which will enable you to select the "offending" column and make the Z coordinate of its 2 ends to be equal so it becomes truly vertical.

8. I have a beam member for which I have assigned a single angle from the American steel table. When I look at the member properties output for that member, the values that STAAD reports for moments of inertia Iz and Iy do not match the values I see in the AISC steel publication for that angle section.

The numbers reported in the STAAD output for Iz and Iy are the moments of inertia about the principal axes of the single angle. The values in the AISC publication that you are comparing them with are most probably the values about the geometric axes. That is very likely the cause of the mis-match.

9. I understand that one should use the REPEAT LOAD command and not the LOAD COMBINATION command when analysing a model for cases where the MEMBER TENSION or MEMBER COMPRESSION command has been used. Talking about load combinations, in Section 5.35 of the STAAD Technical Reference Manual, notes Item (2) mentions that the LOAD COMBINATION command is inappropriate for a PDELTA analysis, and that one should use REPEAT LOADs instead. This appears to be true for NON-LINEAR analysis also. Why?

Before we can explain why, we first need to understand a few facts about loads in STAAD. There are two types of load cases in STAAD : Primary load cases, and Combination load cases.

Primary load cases

A primary load case is one where the load data is directly specified by the user in the form of member loads, joint loads, temperature loads, element pressure loads, etc. It is characterized by the fact that the data generally follow a title which has the syntax

LOAD n

where "n" is the load case number. For example,

LOAD 3

MEMBER LOAD

2 UNI GY -3.4

JOINT LOAD

10 FX 12.5

LOAD 4

ELEMENT LOAD

23 PR GY -1.2

LOAD 5

TEMPERATURE LOAD

15 17 TEMP 40.0 -25.0

Combination load case

Here, the user does not directly specify the load data, but instead asks the program to add up the results of the component cases - which are defined prior to the combination case - after factoring them by the user specified factors. It is characterized by the title which has the syntax

LOAD COMBINATION n

where "n" is the case number of the combination load case.

LOAD COMBINATION 40

3 1.2 4 1.6 5 1.3

What is a REPEAT LOAD type, and Which category does is belong to?

A Repeat Load type is a Primary load case. That is because, when the program runs into this command, it physically creates the load data for this case by assembling together the load information from all the component load cases (after factoring them by the respective load factors) which the user wants to "REPEAT". Thus, when you specify

LOAD 10

REPEAT LOAD

4 1.4 5 1.7

STAAD creates a physical load case called 10 whose contents will include all of the data of load case 4 factored by 1.4, and all of the data of load case 5 factored by 1.7.
If we use the same data used in the definition of the primary load case above, STAAD internally converts the REPEAT LOAD case 10 to the following :

LOAD 10

ELEMENT LOAD

23 PR GY -1.68

TEMPERATURE LOAD

15 17 TEMP 68.0 -42.5

What is the difference between a REPEAT LOAD case and LOAD COMBINATION?

The difference lies in the way STAAD goes about calculating the results - joint displacements, member forces and support reactions. For a load combination case, STAAD simply ALGEBRAICALLY COMBINES THE RESULTS of the component cases after factoring them. In the example shown above, it

gathers the results of load case 3, factors them by 1.2,

gathers the results of load case 4, factors them by 1.6,

gathers the results of load case 5, factors them by 1.3,

and adds them all together. In other words, in order to obtain the results of load 10, it has no need to know what exactly is it that constitues load cases 3, 4 and 5. It just needs to know what the results of those cases are. Thus, the structure is NOT actually analysed for a combination load case. With a REPEAT LOAD case however, the procedure followed is that which occurs for any other primary load case. A load vector {P} is first created, and later, that load vector gets pre-multiplied by the inverted stiffness matrix.

[Kinv] {P}

to obtain the joint displacements. Those displacements are then used to calculate the member forces and support reactions. Thus, the structure IS analysed for that load case {P}.

Why should the difference in the way STAAD treats a REPEAT LOAD case vs. a COMBINATION LOAD case matter?

Normally, if you are doing a linear static analysis - which is what a PERFORM ANALYSIS command does - it should make no difference whether you specify REPEAT or COMBINATION. However, if you are doing a PDELTA analysis, or a NONLINEAR analysis, or cases involving MEMBER TENSION and MEMBER COMPRESSION, etc., it matters. That is because, in those situations, the results of those individual cases acting simultaneously IS NOT the same as the summation of the results of those individual cases acting alone. In other words,

(Results of Load A) + (Results of Load B) is not equal to (Results of Load (A+B))

Take the case of a PDelta analysis. The P-Delta effect comes about from the interaction of the vertical load and the horizontal load. If they do not act simultaneously, there is no P-Delta effect. And the only way to make them act simultaneously is to get the program to compute the displacement with both loads being present in a single load case. A REPEAT LOAD case achieves that. A COMBINATION load case does not.

See Also

Product TechNotes and FAQs

Structural Product TechNotes And FAQs

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

Comments or Corrections?

Bentley's Technical Support Group requests that you please confine any comments you have on this Wiki entry to this "Comments or Corrections?" section. THANK YOU!

Why does the program give some strange numbers when the joints are generated graphically by e.g. copying. We enter a number that has no decimals (7.00m) and in the input file the coordinate is 7.0001.

In STAAD.Pro, there is a concept called a Base Unit system. There are 2 options under this : The English or Imperial units (Foot Pound, etc.) and Metric units (meter, kg, etc.)

The base unit is set at the time of installation of the program. Once it is set, you can see what the setting is, as well as change it, by starting the program, going to the File menu, choosing Configure, and then choosing Base Unit.

If your base unit setting happens to be inconsistent with the units in which you create the model, that will cause the type of problem you mention. For example, if the base unit system is English, and you create the model using Meter and Kg unit, it will cause numbers to be not rounded.

You can rectify it by setting the base unit to be consistent with your working units through the File-Configure option we just described above.

When I use the Node Dimensioning Tool (Tools | Display Node to Node Dimension), how can I turn off just one dimension line rather than all of them with the Remove Node Dimension option?

 You can use the Node to Node Dimension and re-dimension an exisiting dimension line. This will remove only the dimension line that has been re-dimensioned.

I am trying to model a beam connecting to the flange of a column instead of at the center. How is this modeled?

 You have to use a facility called member offsets. You "offset" the face of the beam by a distance equal to half the depth of the column cross-section. An example of this can be found in Example # 7 in the STAADPro Examples Manual. 

 How to model Pile cap attached to batter and vertical piles in STAAD.Pro?

1) The pile cap can be modelled using either plate elements or solid elements. If the thickness of the cap is comparable to its plan dimensions, a solid element model is preferable. If the plan dimensions are much larger than its thickess, plate elements should be a better choice. One drawback of using solid elements is that, by their very nature, they lack rotational degrees of freedom. Consequently, for a monolithic structure such as a concrete pile cap with concrete piles, the rigid connection between piles and the pile cap cannot be properly accounted for, if the cap is modelled using solids.

2) The piles themselves can be modelled using frame members. The supports for the pile come in 2 varieties - skin friction and end bearing. Skin friction action can be accounted for by modelling each pile as several collinear members and specifying a support at each of those common nodes. End bearing action can be modelled using fixed or pinned supports. The support spring stiffness is obtained by multiplying the soil subgrade reaction by the influence area of the associated support node. A standard text book on pile analysis should be a great source of information on obtaining the spring constant of the supports.

In the new 3D rendered window, how can I view the structure in plan, elevation and isometric view like I can with the other windows? Also, how do I pan across the model?

 You can perform rotation and other viewing functions by right-clicking your mouse button and choosing the appropriate viewing tools. Also, you can use the viewing icons in the main toolbar for viewing the model in plan, elevation, isometric, etc. and also to pan and zoom in/out.

When I save a file from the STAAD.Pro GUI, the joint coordinate data and member incidence data are written into the .std file in such a manner that there are several entries per line, separated by semi-colons. I would like it to be written in a way that the joint coordinate data is written as one joint per line and the member incidence data is written as one member per line. Is there some setting in the program to facilitate this?

Close all input files.

From the File menu, select Configure - Input File Format. Switch on the items for which you wish to have the single line format. Click on Accept.

Then, choose File - Open - open the input file. Click on Save. This setting will ensure that all desired data will henceforth be saved in the single line format.

Can you please tell me how to transfer data from EXCEL to STAAD-PRO?

The only data which can presently be transferred from Excel to STAAD is the geometry information, namely, joint coordinates, member incidences, plate element incidences, and solid element incidences. To do this, first select the cells in Excel where you have the numbers, and choose Copy from Excel's edit menu.

Next, come into the STAAD program. The data may be brought into a new STAAD file or an existing STAAD file. Accordingly, open a new file or an existing file.

Select the Geometry page from the left side of the screen, and choose the Beam, Plate or Solid sub-page depending upon the type of information you wish to bring in.

If you are looking to bring it into a New file, close the Snap/Node dialog box which is open on the right hand side of the screen.

For copying the joint coordinate data, click on the appropriate starting cell in the Node Tables grid on the right side, and type Ctrl+V or select paste from the Edit menu.

For beam incidence, plate incidence or solid incidence data, click on the appropriate starting cell in the Beam Tables, Plate Tables or Solid Tables grids on the right side, and type Ctrl+V or select paste from the Edit menu. You should see the numbers you copied from Excel appear in those cells.

How do I graphically display the distance between two nodes?

 Go to Tools | Display Node to Node Dimension or click the dimension icon. If you have kept the original toolbar layout, the icon is in the first row, 3rd group from the left, and it looks like a double arrow with 2 parallel verticle lines on either side.

I have a rather large frame building consisting of several floors. I want to look at individual floors by themselves without the rest of the structure cluttering up the view. Can you tell me how to do that?

Method 1 :

a) Orient the view of your model in such a way as to make it convenient to extract using a mouse, the portion you want to view separately. This can be done from View | Orientation, or by clicking on the icons available for this.

b) From the select menu, select the Geometry cursor. Then, using your mouse, create a window around the region you wish to view. That region will be highlighted.

c) Click the right mouse button and select New View. Or, from the View menu, select New View. Set the button on "Create a new window for the View", and click on OK.

The region will now be displayed in a separate window. Once in this window, you can change the viewing angles using View | Orientation, or through the orientation icons, or simply by pressing the up, down, left or right arrow keys on the keyboard.

Method 2 :

This method involves cutting a section using the Tools - Cut section option. Details are available in Section 2.3.4 of the STAAD.Pro Graphical Environment Manual, which can be accessed from Help - Contents.

How do I access online help in STAAD.Pro? The F1 key does not bring up any help screens.

The F1 key for help is currently not operational in STAAD. We are working on implementing this for one of the forthcoming releases.

To obtain online help in STAAD, you can do one of the following:

From the Help
menu, if you click on Contents, if will bring up all the STAAD manuals. You can search for specific information, or go through the topic list to select the items you want.

From Help, if you click on Multi Media help, it will bring up a set of movies which will explain the procedure for creating a
model.

If you click on the Start button on your Windows desktop, select Programs, choose STAAD.Pro 2001 followed by STAAD.Pro Online
Documentation, it will bring up the same set of information as the one you can access from step (1) above.

How can I convert single line input to multiple line input? The program currently converts my joint coordinate and member incidence data from multiple line to single line input.

 Start STAAD.Pro. Select File - Configure.

Click on the tab called Input File Format

If you want Single line format, switch on the check boxes. If you want Multiple line format, keep them "unchecked".

Click on Accept.

Then from the File menu, open your STAAD input file. When you Save the file from the Graphical screen, the data will be saved in the format you chose in the step above.

How do I merge 2 staad models?

Start STAAD.Pro. Open the first file. Keep it open.

STAAD another instance of STAAD.Pro. Open the second file. Stay in this file.

Go to the Select menu, and Select All Geometry. From the Edit menu, select Copy.

Go back to the screen of the first file. From the Edit menu, select Paste.

You will be prompted to specify the X, Y and Z distances by which to move the structure of the second file before it gets copied to the first structure. Specify those values and click on OK.

After analysis , I get the following warning in the output file :

**ERROR** PLATE NO. 2448(JOINTS 2017 - 2088 - 2160 - 2089)

IS BADLY SHAPED, WARPED, NOT CONVEX, OR NOT NUMBERED COUNTER-CLOCKWISE.

 Plate element should me be modeled using some rules. A plate element’s aspect ratio should be as near to 1:1 as possible. Aspect ratio is defined as the ratio of the length of the shortest side to the longest side of the element. Aspect ratios in excess of 1:4 should be avoided. When assigning nodes to an element in the input data, the nodes must be specified either in clockwise or  counterclockwise order around the perimeter of the element. Kindly find the link to the document which explains the rules for proper modeling of plate elements.

http://communities.bentley.com/products/structural/structural_analysis___design/m/structural_analysis_and_design_gallery/257477.aspx

[[Developing the model]]

See Also

Product TechNotes and FAQs

Structural Product TechNotes And FAQs

External Link

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

Comments or Corrections?

Bentley's Technical Support Group requests that you please confine any comments you have on this Wiki entry to this "Comments or Corrections?" section. THANK YOU!

Hello ,

 There are few instances where the WIND load command is not associated with a specific exposed face. So, the program has to scan through the whole structure to find one. When it runs into what it perceives as intersecting members without a common node at the intersection point, these messages are displayed.

I would suggest you to provide the coordinates of the Exposed area with some tolerance as X range ,Y range and Z range in the wind load case definition ,so that the concerned nodes are covered by the ranges . This helps the program to identify the proper exposed area for wind load. Or you can associate them with a member list or a group name in each case, and the message will disappear.

User is having the query as listed below,
Staad.pro has been successfully activated and runs in fully functional mode still in the activation staus why does it displays it will expire in 5 days.

I appreciate there isnt full integration between STAAD Pro V8i and ProjectWise SS4. However I am keen to understand from users of the products any workflows that enable project teams to use STAAD pro with ProjectWise.

Many thanks

Gavin

Frequently asked questions for STAAD.Pro:

• [[FAQ ON STAAD LICENSE - USL versus STANDARD]]
• [[STAAD.Pro General [FAQ] ]]
• [[STAAD.Pro Aluminum Design [FAQ] ]]
• [[STAAD.Pro Concrete Design [FAQ] ]]
• [[STAAD.Pro Developing The Model [FAQ] ]]
• [[STAAD.Pro Driver Downloads [FAQ] ]]
• [[STAAD.Pro Eigen Solution [FAQ] ]]
• [[STAAD.Pro Instability And Zero Stiffness [FAQ] ]]
• [[STAAD.Pro Load Generation [FAQ] ]]
• [[STAAD.Pro Member Specification [FAQ] ]]
• [[STAAD.Pro Miscellaneous [FAQ] ]]
• [[STAAD.Pro PDELTA Analysis [FAQ] ]]
• [[STAAD.Pro Plates And Solid Elements [FAQ] ]]
• STAAD.Pro Postprocessing [FAQ]
• [[STAAD.Pro Response Spectrum [FAQ] ]]
• [[STAAD.Pro Steel Design [FAQ] ]]
• [[STAAD.Pro Timber Design [FAQ] ]]
• [[STAAD.Pro Time History Analysis [FAQ] ]]
• [[STAAD.Pro Tutorials [FAQ] ]]
• [[STAAD.Pro Import/Export [FAQ] ]]

1. How can I get my RISA model into STAAD.Pro ?

1. How can I get my RISA model into STAAD.Pro ?

There is no way to directly get a RISA model into STAAD.Pro. You may check whether RISA can export in the following formats, both of which can be imported by STAAD.Pro.

1.  CIS/2
2.  3D DXF

Out of these, the CIS/2 is the best option as it lets you transfer not only the wireframe but other member information like Member properties, Material properties, Member orientation, Member end conditions like Releases, Support conditions, Loading information

3D DXF transfer will let you transfer the wireframe only.

These import options in STAAD.Pro can be accessed from within the top menu File > Import

See Also

XXXXXXX(Add more links as needed for other relevant Be Communities content.)XXXXXXX

I have attached a staad model that is a continuous beam with external moments placed at the nodes. The beam is on pinned supports.  My issue is that the torsion created by the external moments does not seem to make sense. Can someone please help me? Thank you!

Catherine

Please help!

I try to get intermediate member force from staad link to excel using VBA openstaad.

I got end force successfully and corrected result complied with staad pro but for intermediate member force the result is incorrect and very far from staad result.

Am i do anything wrong in code?

In excel VBA

Sub()

Public objOpenSTAAD As Object

Public InterForces(0 To 5) As Double

Set objOpenSTAAD = GetObject(, "StaadPro.OpenSTAAD")

'GET INTERMEDIATE MEMBER FORCE FOR MEMBER 2 AT 3.5M. LOAD CASE 101

objOpenSTAAD.Output.GetIntermediateMemberForcesAtDistance 2, 3.5, 101, InterForces()

Cells(9, 16).Value = InterForces(5)

End Sub()

VBA result in excel got -97.49kN-m but STAAD result got only -63.2kN-m????

STAAD Input

STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 26-Aug-13
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KG
JOINT COORDINATES
1 0 0 0; 2 0 5 0; 3 6 5 0; 4 6 0 0; 5 0 0 5; 6 0 5 5; 7 6 5 5; 8 6 0 5;
MEMBER INCIDENCES
1 1 2; 2 2 3; 3 3 4; 4 5 6; 5 6 7; 6 7 8; 7 2 6; 8 3 7;
START GROUP DEFINITION
MEMBER
_B1 2 5
_B2 7 8
JOINT
_F1 1 5
_F2 4 8
END GROUP DEFINITION
DEFINE MATERIAL START
ISOTROPIC CONCRETE
E 2.21467e+009
POISSON 0.17
DENSITY 2402.62
ALPHA 1e-005
DAMP 0.05
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
2 5 7 8 PRIS YD 0.5 ZD 0.2
1 3 4 6 PRIS YD 0.2 ZD 0.2
CONSTANTS
MATERIAL CONCRETE ALL
SUPPORTS
1 4 5 8 FIXED
LOAD 1 LOADTYPE Dead  TITLE DL
SELFWEIGHT Y -1 LIST 1 TO 8
MEMBER LOAD
2 5 7 8 UNI GY -500
2 5 UMOM GX 1000
2 5 CON GX -1000 2.5
2 5 UMOM GY 1000
LOAD 2 LOADTYPE Live  TITLE LL
MEMBER LOAD
2 5 7 8 UNI GY -800
LOAD COMB 101 DL+LL
1 1.0 2 1.0 
LOAD COMB 102 DL
1 1.0 
PERFORM ANALYSIS PRINT ALL
FINISH

Question:

How to find STAAD.Pro Verification Example Models mentioned in Help manual?

Answer:

The default location is C:\SProV8i\STAAD\Examp and one should select the corresponding country folder.

You can simply click on “Turn on/off Individual Beam Level” icon. On doing this you can see that there is a change in the cursor image. You can rubber band the portion on the members where you do not want to see the UR.

Thanks for your answer.

I have a staad model command file shown below

STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 01-Aug-13
JOB CLIENT BP
JOB NO SCPX
JOB PART Mx71 (100-CROSVER-PLT01, 02, 03)
END JOB INFORMATION
INPUT WIDTH 79
*
SET NL 500
*SET ITERLIM 20
UNIT METER KN
JOINT COORDINATES
225 0.999836 0.225 1; 241 0.999836 2.5 1.00014; 242 2.29984 0.225 1;
243 2.29984 2.5 1.00014; 244 0.999836 0.225 2.80001; 245 0.999836 2.5 2.80014;
246 2.29984 0.225 2.80001; 247 2.29984 2.5 2.80014; 248 0.999836 0.225 12.15;
249 0.999836 2.5 12.1501; 250 2.29984 0.225 12.15; 251 2.29984 2.5 12.1501;
252 0.999836 0.225 16.1; 253 0.999836 2.5 16.1001; 254 2.29984 0.225 16.1;
255 2.29984 2.5 16.1001; 256 0.999836 2.5 1.9; 257 2.29984 2.5 1.90014;
258 0.999836 2.5 3.73515; 259 2.29984 2.5 3.73515; 260 0.999836 2.5 4.67015;
261 2.29984 2.5 4.67015; 262 0.999836 2.5 5.60514; 263 2.29984 2.5 5.60514;
264 0.999836 2.5 6.54015; 265 2.29984 2.5 6.54015; 266 0.999836 2.5 7.47515;
267 2.29984 2.5 7.47515; 268 0.999836 2.5 8.41014; 269 2.29984 2.5 8.41014;
270 0.999836 2.5 9.34515; 271 2.29984 2.5 9.34515; 272 0.999836 2.5 10.2801;
273 2.29984 2.5 10.2801; 274 0.999836 2.5 11.2151; 275 2.29984 2.5 11.2151;
276 0.999836 2.5 13.1001; 277 2.29984 2.5 13.1001; 278 0.999836 2.5 14.1001;
279 2.29984 2.5 14.1001; 280 0.999836 2.5 15.1001; 281 2.29984 2.5 15.1001;
********************************************************************************************************
MEMBER INCIDENCES
329 225 241; 330 242 243; 331 241 243; 332 225 243; 333 242 241; 334 244 245;
335 246 247; 336 245 247; 337 244 247; 338 246 245; 339 248 249; 340 250 251;
341 249 251; 342 248 251; 343 250 249; 344 252 253; 345 254 255; 346 253 255;
347 252 255; 348 254 253; 349 243 257; 350 247 259; 351 251 277; 352 249 276;
353 241 256; 354 245 258; 355 256 245; 356 257 247; 357 256 257; 358 258 260;
359 259 261; 360 258 259; 361 260 262; 362 261 263; 363 260 261; 364 262 264;
365 263 265; 366 262 263; 367 264 266; 368 265 267; 369 264 265; 370 266 268;
371 267 269; 372 266 267; 373 268 270; 374 269 271; 375 268 269; 376 270 272;
377 271 273; 378 270 271; 379 272 274; 380 273 275; 381 272 273; 382 274 249;
383 275 251; 384 274 275; 385 276 278; 386 277 279; 387 276 277; 388 278 280;
389 279 281; 390 278 279; 391 280 253; 392 281 255; 393 280 281; 394 241 257;
395 245 257; 396 245 259; 397 259 260; 398 260 263; 399 263 264; 400 264 267;
401 267 268; 402 268 271; 403 271 272; 404 272 275; 405 275 249; 406 249 277;
407 277 278; 408 278 281; 409 281 253;
********************************************************************************************************
START GROUP DEFINITION
JOINT
_SWAY 241 243 245 247 249 251 253 255
MEMBER
_MAINCOLUMS 329 330 344 345
_FIREPROOFING 329 330 344 345
_COLLEVEL1 329 330 344 345
_CONNECTION1 331 336 341 346 357 360 363 366 369 372 375 378 381 384 387 390 -
393
_CONNECTION2 394 TO 409
_CONNECTION3 332 333 337 338 342 343 347 348
_CONNECTION4 349 TO 356 382 383 391 392
END GROUP DEFINITION
********************************************************************************************************
DEFINE MATERIAL START
ISOTROPIC STEEL
E 1.99947e+008
POISSON 0.3
DENSITY 76.8191
ALPHA 6e-006
DAMP 0.03
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
331 336 341 346 357 360 363 366 369 372 375 378 381 384 387 390 -
393 TABLE ST W8X10
349 351 TO 353 355 356 385 386 388 389 391 392 TABLE ST W6X16
350 354 358 359 361 362 364 365 367 368 370 371 373 374 376 377 379 380 382 -
383 TABLE ST W10X33
329 330 334 335 339 340 344 345 TABLE ST W10X33
332 333 337 338 342 343 347 348 TABLE ST HSSP3X0.25
394 TO 409 TABLE ST HSSP3X0.25
CONSTANTS
BETA 90 MEMB 329 330 334 335 339 340 344 345
MATERIAL STEEL ALL
*****************
**MEMBER RELEASE
*****************
MEMBER RELEASE
331 336 341 346 357 360 363 366 369 372 375 378 381 384 387 390 393 START MY MZ
331 336 341 346 357 360 363 366 369 372 375 378 381 384 387 390 393 END MY MZ
SUPPORTS
225 242 244 246 248 250 252 254 PINNED
MEMBER TRUSS
332 333 337 338 342 343 347 348 394 TO 409
DEFINE WIND LOAD
TYPE 2
<! STAAD PRO GENERATED DATA DO NOT MODIFY !!!
ASCE-7-2002:PARAMS 58.000 M/SEC 4 2 3 0 0.000 FT 0.000 FT 0.000 FT 1 -
0 40.000 FT 25.000 FT 0.500 FT 0.600 2.000 0.010 -
0 0 1 0 1.044 1.000 1.000 0.850 0 -
1 1 0 1.000 1.800 -0.550
!> END GENERATED DATA BLOCK
INT 2.67977 2.67977 2.7487 2.81169 2.8698 2.9238 2.9743 3.02178 3.06661 3.10912 -
 3.14955 3.18812 3.22502 3.2604 3.29439 2.85566 HEIG  0  4.57201  5.15816 -
 5.74432  6.33047  6.91663  7.50278  8.08894  8.67509  9.26125  9.8474  10.4336 -
 11.0197  11.6059  12.192  12.192
<! STAAD PRO GENERATED DATA DO NOT MODIFY !!!
ASCE-7-2002:PARAMS 58.000 M/SEC 4 2 3 0 0.000 FT 0.000 FT 0.000 FT 1 -
0 40.000 FT 25.000 FT 0.500 FT 0.600 2.000 0.010 -
0 0 0 0 1.044 1.000 1.150 0.850 0 -
1 1 0 1.000 1.800 -0.550
!> END GENERATED DATA BLOCK
****************************************************************************************************
LOAD 1 LOADTYPE Seismic  TITLE EX
* LOAD 3 LOADTYPE Dead  TITLE DL STRUCTURE
SELFWEIGHT X 1
MEMBER LOAD
349 CON GX 0.72 0.28
356 CON GX 0.72 0.18
392 CON GX 0.72 0.72
389 CON GX 0.72 0.92
*LOAD 4 LOADTYPE Dead  TITLE DL GRATING
MEMBER LOAD
349 TO 356 358 359 361 362 364 365 367 368 370 371 373 374 376 377 379 380 -
382 383 385 386 388 389 391 392 UNI GX 0.39
*LOAD 5 LOADTYPE Dead  TITLE DL HANDRAIL
MEMBER LOAD
349 TO 356 358 359 361 362 364 365 367 368 370 371 373 374 376 377 379 380 -
382 383 385 386 388 389 391 392 UNI GX 0.25
*LOAD 6 LOADTYPE Dead  TITLE DL PIPING
*LOAD 7 LOADTYPE Dead  TITLE DL EQUIPMENT
*LOAD 8 LOADTYPE Dead  TITLE DL ELECTRICAL
*LOAD 9 LOADTYPE Dead  TITLE DL FIREPROOFING
*LOAD 10 LOADTYPE Dead  TITLE DL PIPING-LIQUID
*LOAD 11 LOADTYPE Dead  TITLE DL EQUIPMENT-LIQUID
*LOAD 12 LOADTYPE Live  TITLE LL PLATFORM LIVE LOADS
***********************************************************************************************************
LOAD 2 LOADTYPE Seismic  TITLE EZ
* LOAD 3 LOADTYPE Dead  TITLE DL STRUCTURE
SELFWEIGHT Z 1
MEMBER LOAD
349 CON GZ 0.72 0.28
356 CON GZ 0.72 0.18
392 CON GZ 0.72 0.72
389 CON GZ 0.72 0.92
*LOAD 4 LOADTYPE Dead  TITLE DL GRATING
MEMBER LOAD
349 TO 356 358 359 361 362 364 365 367 368 370 371 373 374 376 377 379 380 -
382 383 385 386 388 389 391 392 UNI GZ 0.39
*LOAD 5 LOADTYPE Dead  TITLE DL HANDRAIL
MEMBER LOAD
349 TO 356 358 359 361 362 364 365 367 368 370 371 373 374 376 377 379 380 -
382 383 385 386 388 389 391 392 UNI GZ 0.25
*LOAD 6 LOADTYPE Dead  TITLE DL PIPING
*LOAD 7 LOADTYPE Dead  TITLE DL EQUIPMENT
*LOAD 8 LOADTYPE Dead  TITLE DL ELECTRICAL
*LOAD 9 LOADTYPE Dead  TITLE DL FIREPROOFING
*LOAD 10 LOADTYPE Dead  TITLE DL PIPING-LIQUID
*LOAD 11 LOADTYPE Dead  TITLE DL EQUIPMENT-LIQUID
*LOAD 12 LOADTYPE Live  TITLE LL PLATFORM LIVE LOADS
****************************************************************************************************
LOAD 3 LOADTYPE Dead  TITLE DL STRUCTURE
SELFWEIGHT Y -1
*Stair dead weight assumed to be 1.0 Kg/m2
*Wstair dl = 1.0*3.6*0.8/4 = 0.72 kN
MEMBER LOAD
349 CON GY -0.72 0.28
356 CON GY -0.72 0.18
392 CON GY -0.72 0.72
389 CON GY -0.72 0.92
****************************************************************************************************
LOAD 4 LOADTYPE Dead  TITLE DL GRATING
MEMBER LOAD
*Grating weight assumed to be 60 Kg/m2
* Wgr = 60*1.3/2 * 1/100 = 0.39 kN/m2
349 TO 356 358 359 361 362 364 365 367 368 370 371 373 374 376 377 379 380 -
382 383 385 386 388 389 391 392 UNI GY -0.39
****************************************************************************************************
LOAD 5 LOADTYPE Dead  TITLE DL HANDRAIL
* Hand rail assumed to be 25 Kg/m = 0.25 kN/m
MEMBER LOAD
331 346 349 TO 356 358 359 361 362 364 365 367 368 370 371 373 374 376 377 -
379 380 382 383 385 386 388 389 391 392 UNI GY -0.25
*******************************************************************************************************
LOAD 6 LOADTYPE Dead  TITLE EMPTY  WEIGHT PIPING
JOINT LOAD
246 FY -0.0001
****************************************************************************************************
LOAD 7 LOADTYPE Dead  TITLE EMPTY  WEIGHT EQUIPMENT
JOINT LOAD
246 FY -1e-005
********************************************************************************************************
LOAD 8 LOADTYPE Dead  TITLE DL ELECTRICAL
JOINT LOAD
246 FY -1e-005
********************************************************************************************************
LOAD 9 LOADTYPE Dead  TITLE DL FIREPROOFING
JOINT LOAD
246 FY -0.0001
********************************************************************************************************
LOAD 10 LOADTYPE Dead  TITLE OPERATING WEIGHT PIPING
JOINT LOAD
246 FY -0.0001
********************************************************************************************************
LOAD 11 LOADTYPE Dead  TITLE OPERATING WEIGHT EQUIPMENT
JOINT LOAD
246 FY -0.0001
****************************************************************************************************
LOAD 12 LOADTYPE Live  TITLE LL PLATFORM LIVE LOADS
* Live load = 3.0 kN/m2
* Wll = 3.0*1.3/2 = 1.95 kN/m
MEMBER LOAD
349 TO 356 358 359 361 362 364 365 367 368 370 371 373 374 376 377 379 380 -
382 383 385 386 388 389 391 392 UNI GY -1.95
*Stair live load to be 2.5 Kg/m2 "ref to Civil Engineering Basic Design Data CB-MX00ZZ-CV-SPE-0001-000 Clause 9.2"
*Wstair ll = 5*3.6*0.8/4 = 3.60 kN
349 CON GY -3.6 0.28
356 CON GY -3.6 0.18
392 CON GY -3.6 0.72
389 CON GY -3.6 0.92
********************************************************************************************************
LOAD 13 LOADTYPE Temperature  TITLE ANCHOR LOAD (X)
JOINT LOAD
246 FY -1e-005
********************************************************************************************************
LOAD 14 LOADTYPE Accidental  TITLE ANCHOR LOAD (Z)
JOINT LOAD
246 FY -0.0001
********************************************************************************************************
LOAD 15 LOADTYPE Temperature  TITLE THERMAL FRICTION X
JOINT LOAD
246 FY -0.0001
********************************************************************************************************
LOAD 16 LOADTYPE Temperature  TITLE THERMAL FRICTION Z
JOINT LOAD
246 FY -0.0001
********************************************************************************************************
LOAD 17 LOADTYPE Fluids  TITLE HYDRO
JOINT LOAD
246 FY -0.0001
********************************************************************************************************
LOAD 18 LOADTYPE Accidental  TITLE MAINTENANCE
JOINT LOAD
246 FY -0.0001
LOAD 19 LOADTYPE Temperature  TITLE THERMAL STRUCTURE (+VE)
TEMPERATURE LOAD
329 TO 409 TEMP 26
LOAD 20 LOADTYPE Temperature  TITLE THERMAL STRUCTURE(-VE)
TEMPERATURE LOAD
329 TO 409 TEMP -41
********************************************************************************************************
LOAD 21 LOADTYPE Wind  TITLE WL STRUCTURE X
WIND LOAD X 1 TYPE 2 XR -20 40 OPEN
********************************************************************************************************
LOAD 22 LOADTYPE Wind  TITLE WL STRUCTURE Z
WIND LOAD Z 1 TYPE 2 ZR -0.1 25 OPEN
********************************************************************************************************
LOAD 23 LOADTYPE Wind  TITLE WL PIPING X
JOINT LOAD
246 FX 0.0001
********************************************************************************************************
LOAD 24 LOADTYPE Wind  TITLE WL PIPING Z
JOINT LOAD
246 FZ -0.0001
********************************************************************************************************
LOAD 25 LOADTYPE Wind  TITLE WL EQUIPMENT X
JOINT LOAD
246 FX -0.0001
********************************************************************************************************
LOAD 26 LOADTYPE Wind  TITLE WL EQUIPMENT Z
JOINT LOAD
246 FZ 0.0001
********************************************************************************************************
LOAD 27 LOADTYPE Wind  TITLE WL ELECTRICAL X
JOINT LOAD
246 FX -0.0001
********************************************************************************************************
LOAD 28 LOADTYPE Wind  TITLE WL ELECTRICAL Z
JOINT LOAD
246 FZ -0.0001
********************************************************************************************************
LOAD 29 LOADTYPE Wind  TITLE EQ EQUIPMENT X
JOINT LOAD
246 FX 0.0001
********************************************************************************************************
LOAD 30 LOADTYPE Wind  TITLE EQ EQUIPMENT Z
JOINT LOAD
246 FZ 0.0001
********************************************************************************************************
LOAD 31 LOADTYPE Accidental  TITLE CONTINGENCY ( +VE FRICTION)
JOINT LOAD
246 FY -0.0001
********************************************************************************************************
LOAD 32 LOADTYPE Accidental  TITLE CONTINGENCY ( -VE FRICTION)
JOINT LOAD
246 FY -0.0001
LOAD 33 LOADTYPE Accidental  TITLE SNOW
JOINT LOAD
246 FY -0.0001
*********************************************************************************************************
**********************************************************************************************************
** INDIVIDUAL TOTAL LOADS**
*********************************************************************************************************
LOAD 1001 DEAD D
REPEAT LOAD
3 1.0 4 1.0 5 1.0 8 1.0 9 1.0
LOAD 1002 LOADTYPE None  TITLE EMPTY WEIGHT PIPING AND EQUIPMENT
REPEAT LOAD
6 1.0 7 1.0
LOAD 1003 LIVE L
REPEAT LOAD
12 1.0
LOAD 1004 LOADTYPE None  TITLE OPERATING WEIGHT PIPING AND EQUIPMENT
REPEAT LOAD
10 1.0 11 1.0
LOAD 1005 ANCHOR FORCES AF (X)
REPEAT LOAD
13 1.0
LOAD 1006 ANCHOR FORCES AF (Z)
REPEAT LOAD
14 1.0
LOAD 1007 FRICTION FORCES FF (X)
REPEAT LOAD
15 1.0
LOAD 1008 FRICTION FORCES FF (Z)
REPEAT LOAD
16 1.0
LOAD 1009 HYDROTEST PT
REPEAT LOAD
17 1.0
LOAD 1010 MAINTENANCE M
REPEAT LOAD
18 1.0
LOAD 1011 CONTINGENCY + C
REPEAT LOAD
31 1.0
LOAD 1012 CONTINGENCY - C
REPEAT LOAD
32 1.0
LOAD 1013 LOADTYPE None  TITLE TEMPERATURE FORCE TF (+VE)
REPEAT LOAD
19 1.0
LOAD 1014 LOADTYPE None  TITLE TEMPERATURE FORCE TF (-VE)
REPEAT LOAD
20 1.0
LOAD 1015 WIND WX
REPEAT LOAD
21 1.0 23 1.0 25 1.0 27 1.0
LOAD 1016 WIND WZ
REPEAT LOAD
22 1.0 24 1.0 26 1.0 28 1.0
LOAD 1017 LOADTYPE None  TITLE ( SEISMIC  X DIRECTION)
REPEAT LOAD
1 0.406 29 0.406
LOAD 1018 LOADTYPE None  TITLE ( SEISMIC  Z DIRECTION)
REPEAT LOAD
2 0.377 30 0.377
LOAD 1019 LOADTYPE None  TITLE ( SNOW)
REPEAT LOAD
33 1.0
***************************************************************************
*** ALLOWABLE STRESS DESIGN LOAD COMBINATIONS***
***************************************************************************
* 1a. Ds + Do + Ff + T + Af
LOAD COMB 101 COMBINATION LOAD CASE 101
1001 1.0 1004 1.0 1007 1.0 1008 1.0 1005 1.0 1006 1.0 1013 1.0
LOAD COMB 102 COMBINATION LOAD CASE 102
1001 1.0 1004 1.0 1007 1.0 1008 -1.0 1005 1.0 1006 -1.0 1013 1.0
LOAD COMB 103 COMBINATION LOAD CASE 103
1001 1.0 1004 1.0 1007 -1.0 1008 1.0 1005 -1.0 1006 1.0 1013 1.0
LOAD COMB 104 COMBINATION LOAD CASE 104
1001 1.0 1004 1.0 1007 -1.0 1008 -1.0 1005 -1.0 1006 -1.0 1013 1.0
LOAD COMB 105 COMBINATION LOAD CASE 105
1001 1.0 1004 1.0 1007 1.0 1008 1.0 1005 1.0 1006 1.0 1014 1.0
LOAD COMB 106 COMBINATION LOAD CASE 106
1001 1.0 1004 1.0 1007 1.0 1008 -1.0 1005 1.0 1006 -1.0 1014 1.0
LOAD COMB 107 COMBINATION LOAD CASE 107
1001 1.0 1004 1.0 1007 -1.0 1008 1.0 1005 -1.0 1006 1.0 1014 1.0
LOAD COMB 108 COMBINATION LOAD CASE 108
1001 1.0 1004 1.0 1007 -1.0 1008 -1.0 1005 -1.0 1006 -1.0 1014 1.0
* 1b. Ds + Do + Ff + T + Af  +  S
LOAD COMB 109 COMBINATION LOAD CASE 109
1001 1.0 1004 1.0 1019 1.0 1007 1.0 1008 1.0 1005 1.0 1006 1.0 1014 1.0
LOAD COMB 110 COMBINATION LOAD CASE 110
1001 1.0 1004 1.0 1019 1.0 1007 1.0 1008 -1.0 1005 1.0 1006 -1.0 1014 1.0
LOAD COMB 111 COMBINATION LOAD CASE 111
1001 1.0 1004 1.0 1019 1.0 1007 -1.0 1008 1.0 1005 -1.0 1006 1.0 1014 1.0
LOAD COMB 112 COMBINATION LOAD CASE 112
1001 1.0 1004 1.0 1019 1.0 1007 -1.0 1008 -1.0 1005 -1.0 1006 -1.0 1014 1.0
* 1c. Ds + Do + Ff + T + Af  +  L
LOAD COMB 113 COMBINATION LOAD CASE 113
1001 1.0 1004 1.0 1003 1.0 1007 1.0 1008 1.0 1005 1.0 1006 1.0 1013 1.0
LOAD COMB 114 COMBINATION LOAD CASE 114
1001 1.0 1004 1.0 1003 1.0 1007 1.0 1008 -1.0 1005 1.0 1006 -1.0 1013 1.0
LOAD COMB 115 COMBINATION LOAD CASE 115
1001 1.0 1004 1.0 1003 1.0 1007 -1.0 1008 1.0 1005 -1.0 1006 1.0 1013 1.0
LOAD COMB 116 COMBINATION LOAD CASE 116
1001 1.0 1004 1.0 1003 1.0 1007 -1.0 1008 -1.0 1005 -1.0 1006 -1.0 1013 1.0
LOAD COMB 117 COMBINATION LOAD CASE 117
1001 1.0 1004 1.0 1003 1.0 1007 1.0 1008 1.0 1005 1.0 1006 1.0 1014 1.0
LOAD COMB 118 COMBINATION LOAD CASE 118
1001 1.0 1004 1.0 1003 1.0 1007 1.0 1008 -1.0 1005 1.0 1006 -1.0 1014 1.0
LOAD COMB 119 COMBINATION LOAD CASE 119
1001 1.0 1004 1.0 1003 1.0 1007 -1.0 1008 1.0 1005 -1.0 1006 1.0 1014 1.0
LOAD COMB 120 COMBINATION LOAD CASE 120
1001 1.0 1004 1.0 1003 1.0 1007 -1.0 1008 -1.0 1005 -1.0 1006 -1.0 1014 1.0
* 1d. Ds + Do + Ff + T + Af  +  0.75L + 0.75S
LOAD COMB 121 COMBINATION LOAD CASE 121
1001 1.0 1004 1.0 1003 0.75 1019 0.75 1007 1.0 1008 1.0 1005 1.0 1006 1.0 -
1014 1.0
LOAD COMB 122 COMBINATION LOAD CASE 122
1001 1.0 1004 1.0 1003 0.75 1019 0.75 1007 1.0 1008 -1.0 1005 1.0 1006 -1.0 -
1014 1.0
LOAD COMB 123 COMBINATION LOAD CASE 123
1001 1.0 1004 1.0 1003 0.75 1019 0.75 1007 -1.0 1008 1.0 1005 -1.0 1006 1.0 -
1014 1.0
LOAD COMB 124 COMBINATION LOAD CASE 124
1001 1.0 1004 1.0 1003 0.75 1019 0.75 1007 -1.0 1008 -1.0 1005 -1.0 -
1006 -1.0 1014 1.0
*2a. Ds + Do + Af + 0.6W
LOAD COMB 125 COMBINATION LOAD CASE 125
1001 1.0 1004 1.0 1005 1.0 1006 1.0 1015 0.6
LOAD COMB 126 COMBINATION LOAD CASE 126
1001 1.0 1004 1.0 1005 1.0 1006 -1.0 1015 0.6
LOAD COMB 127 COMBINATION LOAD CASE 127
1001 1.0 1004 1.0 1005 -1.0 1006 1.0 1015 -0.6
LOAD COMB 128 COMBINATION LOAD CASE 128
1001 1.0 1004 1.0 1005 -1.0 1006 -1.0 1015 -0.6
LOAD COMB 129 COMBINATION LOAD CASE 129
1001 1.0 1004 1.0 1005 1.0 1006 1.0 1016 0.6
LOAD COMB 130 COMBINATION LOAD CASE 130
1001 1.0 1004 1.0 1005 1.0 1006 -1.0 1016 -0.6
LOAD COMB 131 COMBINATION LOAD CASE 131
1001 1.0 1004 1.0 1005 -1.0 1006 1.0 1016 0.6
LOAD COMB 132 COMBINATION LOAD CASE 132
1001 1.0 1004 1.0 1005 -1.0 1006 -1.0 1016 -0.6
* 2b. (1 + 0.14SDS) (Ds + Do) + Af + 0.7Eo
LOAD COMB 133 COMBINATION LOAD CASE 133
1001 1.12 1004 1.12 1005 1.0 1006 1.0 1017 0.7 1018 0.21
LOAD COMB 134 COMBINATION LOAD CASE 134
1001 1.12 1004 1.12 1005 1.0 1006 -1.0 1017 0.7 1018 -0.21
LOAD COMB 135 COMBINATION LOAD CASE 135
1001 1.12 1004 1.12 1005 -1.0 1006 1.0 1017 -0.7 1018 0.21
LOAD COMB 136 COMBINATION LOAD CASE 136
1001 1.12 1004 1.12 1005 -1.0 1006 -1.0 1017 -0.7 1018 -0.21
LOAD COMB 137 COMBINATION LOAD CASE 137
1001 1.12 1004 1.12 1005 1.0 1006 1.0 1017 0.21 1018 0.7
LOAD COMB 138 COMBINATION LOAD CASE 138
1001 1.12 1004 1.12 1005 1.0 1006 -1.0 1017 0.21 1018 -0.7
LOAD COMB 139 COMBINATION LOAD CASE 139
1001 1.12 1004 1.12 1005 -1.0 1006 1.0 1017 -0.21 1018 0.7
LOAD COMB 140 COMBINATION LOAD CASE 140
1001 1.12 1004 1.12 1005 -1.0 1006 -1.0 1017 -0.21 1018 -0.7
* 2c. Ds + Do + Af + 0.75(0.6W) + 0.75S + 0.75L
LOAD COMB 141 COMBINATION LOAD CASE 141
1001 1.0 1004 1.0 1003 0.75 1019 0.75 1005 1.0 1006 1.0 1015 0.45
LOAD COMB 142 COMBINATION LOAD CASE 142
1001 1.0 1004 1.0 1003 0.75 1019 0.75 1005 1.0 1006 -1.0 1015 0.45
LOAD COMB 143 COMBINATION LOAD CASE 143
1001 1.0 1004 1.0 1003 0.75 1019 0.75 1005 -1.0 1006 1.0 1015 -0.45
LOAD COMB 144 COMBINATION LOAD CASE 144
1001 1.0 1004 1.0 1003 0.75 1019 0.75 1005 -1.0 1006 -1.0 1015 -0.45
LOAD COMB 145 COMBINATION LOAD CASE 145
1001 1.0 1004 1.0 1003 0.75 1019 0.75 1005 1.0 1006 1.0 1016 0.45
LOAD COMB 146 COMBINATION LOAD CASE 146
1001 1.0 1004 1.0 1003 0.75 1019 0.75 1005 1.0 1006 -1.0 1016 -0.45
LOAD COMB 147 COMBINATION LOAD CASE 147
1001 1.0 1004 1.0 1005 -1.0 1006 1.0 1016 0.45
LOAD COMB 148 COMBINATION LOAD CASE 148
1001 1.0 1004 1.0 1005 -1.0 1006 -1.0 1016 -0.45
* 2d. (Ds + 0.14SDS) (Ds + Do) + Af + 0.75(0.7Eo) + 0.75S + 0.75L
LOAD COMB 149 COMBINATION LOAD CASE 149
1001 1.12 1004 1.12 1003 0.75 1019 0.75 1005 1.0 1006 1.0 1017 0.525 -
1018 0.158
LOAD COMB 150 COMBINATION LOAD CASE 150
1001 1.12 1004 1.12 1003 0.75 1019 0.75 1005 1.0 1006 -1.0 1017 0.525 -
1018 -0.158
LOAD COMB 151 COMBINATION LOAD CASE 151
1001 1.12 1004 1.12 1003 0.75 1019 0.75 1005 -1.0 1006 1.0 1017 -0.525 -
1018 0.158
LOAD COMB 152 COMBINATION LOAD CASE 152
1001 1.12 1004 1.12 1003 0.75 1019 0.75 1005 -1.0 1006 -1.0 1017 -0.525 -
1018 -0.158
LOAD COMB 153 COMBINATION LOAD CASE 153
1001 1.12 1004 1.12 1003 0.75 1019 0.75 1005 1.0 1006 1.0 1017 0.158 -
1018 0.525
LOAD COMB 154 COMBINATION LOAD CASE 154
1001 1.12 1004 1.12 1003 0.75 1019 0.75 1005 1.0 1006 -1.0 1017 0.158 -
1018 -0.525
LOAD COMB 155 COMBINATION LOAD CASE 155
1001 1.12 1004 1.12 1003 0.75 1019 0.75 1005 -1.0 1006 1.0 1017 -0.158 -
1018 0.525
LOAD COMB 156 COMBINATION LOAD CASE 156
1001 1.12 1004 1.12 1003 0.75 1019 0.75 1005 -1.0 1006 -1.0 1017 -0.158 -
1018 -0.525
* 3. Ds + (De or 0.6Do) + 0.6W
LOAD COMB 157 COMBINATION LOAD CASE 157
1001 1.0 1002 1.0 1015 0.6
LOAD COMB 158 COMBINATION LOAD CASE 158
1001 1.0 1002 1.0 1015 -0.6
LOAD COMB 159 COMBINATION LOAD CASE 159
1001 1.0 1002 1.0 1016 0.6
LOAD COMB 160 COMBINATION LOAD CASE 160
1001 1.0 1002 1.0 1016 -0.6
* 4. (0.9 - 0.14SDS) (Ds) + (0.6 - 0.14SDS) (Do) + Af + 0.7Eo
LOAD COMB 161 COMBINATION LOAD CASE 161
1001 0.78 1004 0.48 1005 1.0 1006 1.0 1017 0.7 1018 0.21
LOAD COMB 162 COMBINATION LOAD CASE 162
1001 0.78 1004 0.48 1005 1.0 1006 -1.0 1017 0.7 1018 -0.21
LOAD COMB 163 COMBINATION LOAD CASE 163
1001 0.78 1004 0.48 1005 -1.0 1006 1.0 1017 -0.7 1018 0.21
LOAD COMB 164 COMBINATION LOAD CASE 164
1001 0.78 1004 0.48 1005 -1.0 1006 -1.0 1017 -0.7 1018 -0.21
LOAD COMB 165 COMBINATION LOAD CASE 165
1001 0.78 1004 0.48 1005 1.0 1006 1.0 1017 0.21 1018 0.7
LOAD COMB 166 COMBINATION LOAD CASE 166
1001 0.78 1004 0.48 1005 1.0 1006 -1.0 1017 0.21 1018 -0.7
LOAD COMB 167 COMBINATION LOAD CASE 167
1001 0.78 1004 0.48 1005 -1.0 1006 1.0 1017 -0.21 1018 0.7
LOAD COMB 168 COMBINATION LOAD CASE 168
1001 0.78 1004 0.48 1005 -1.0 1006 -1.0 1017 -0.21 1018 -0.7
* 5. Ds + Dt + 0.3W
LOAD COMB 169 COMBINATION LOAD CASE 169
1001 1.0 1009 1.0 1015 0.3
LOAD COMB 170 COMBINATION LOAD CASE 170
1001 1.0 1009 1.0 1015 -0.3
LOAD COMB 171 COMBINATION LOAD CASE 171
1001 1.0 1009 1.0 1016 0.3
LOAD COMB 172 COMBINATION LOAD CASE 172
1001 1.0 1009 1.0 1016 -0.3
***************************************************************************
***** STRENGTH DESIGN LOAD COMBINATIONS
***************************************************************************
* 1a. 1.4 (Ds + Do + Ff + T + Af)
LOAD COMB 201 COMBINATION LOAD CASE 201
1001 1.4 1004 1.4 1007 1.4 1008 1.4 1005 1.4 1006 1.4 1013 1.4
LOAD COMB 202 COMBINATION LOAD CASE 202
1001 1.4 1004 1.4 1007 1.4 1008 -1.4 1005 1.4 1006 -1.4 1013 1.4
LOAD COMB 203 COMBINATION LOAD CASE 203
1001 1.4 1004 1.4 1007 -1.4 1008 1.4 1005 -1.4 1006 1.4 1013 1.4
LOAD COMB 204 COMBINATION LOAD CASE 204
1001 1.4 1004 1.4 1007 -1.4 1008 -1.4 1005 -1.4 1006 -1.4 1013 1.4
LOAD COMB 205 COMBINATION LOAD CASE 205
1001 1.4 1004 1.4 1007 1.4 1008 1.4 1005 1.4 1006 1.4 1014 1.4
LOAD COMB 206 COMBINATION LOAD CASE 206
1001 1.4 1004 1.4 1007 1.4 1008 -1.4 1005 1.4 1006 -1.4 1014 1.4
LOAD COMB 207 COMBINATION LOAD CASE 207
1001 1.4 1004 1.4 1007 -1.4 1008 1.4 1005 -1.4 1006 1.4 1014 1.4
LOAD COMB 208 COMBINATION LOAD CASE 208
1001 1.4 1004 1.4 1007 -1.4 1008 -1.4 1005 -1.4 1006 -1.4 1014 1.4
* 1b. 1.2 (Ds + Do + Ff + T + Af) + 1.6L + 0.5S
LOAD COMB 209 COMBINATION LOAD CASE 209
1001 1.2 1004 1.2 1003 1.6 1007 1.2 1008 1.2 1005 1.2 1006 1.2 1013 1.2
LOAD COMB 210 COMBINATION LOAD CASE 210
1001 1.2 1004 1.2 1003 1.6 1007 1.2 1008 -1.2 1005 1.2 1006 -1.2 1013 1.2
LOAD COMB 211 COMBINATION LOAD CASE 211
1001 1.2 1004 1.2 1003 1.6 1007 -1.2 1008 1.2 1005 -1.2 1006 1.2 1013 1.2
LOAD COMB 212 COMBINATION LOAD CASE 212
1001 1.2 1004 1.2 1003 1.6 1007 -1.2 1008 -1.2 1005 -1.2 1006 -1.2 1013 1.2
LOAD COMB 213 COMBINATION LOAD CASE 213
1001 1.2 1004 1.2 1019 0.5 1003 1.6 1007 1.2 1008 1.2 1005 1.2 1006 1.2 -
1014 1.2
LOAD COMB 214 COMBINATION LOAD CASE 214
1001 1.2 1004 1.2 1019 0.5 1003 1.6 1007 1.2 1008 -1.2 1005 1.2 1006 -1.2 -
1014 1.2
LOAD COMB 215 COMBINATION LOAD CASE 215
1001 1.2 1004 1.2 1019 0.5 1003 1.6 1007 -1.2 1008 1.2 1005 -1.2 1006 1.2 -
1014 1.2
LOAD COMB 216 COMBINATION LOAD CASE 216
1001 1.2 1004 1.2 1019 0.5 1003 1.6 1007 -1.2 1008 -1.2 1005 -1.2 1006 -1.2 -
1014 1.2
* 1c. 1.2 (Ds + Do + Ff + T + Af) + 1.6S + L
LOAD COMB 217 COMBINATION LOAD CASE 217
1001 1.2 1004 1.2 1019 1.6 1003 1.0 1007 1.2 1008 1.2 1005 1.2 1006 1.2 -
1014 1.2
LOAD COMB 218 COMBINATION LOAD CASE 218
1001 1.2 1004 1.2 1019 1.6 1003 1.0 1007 1.2 1008 -1.2 1005 1.2 1006 -1.2 -
1014 1.2
LOAD COMB 219 COMBINATION LOAD CASE 219
1001 1.2 1004 1.2 1019 1.6 1003 1.0 1007 -1.2 1008 1.2 1005 -1.2 1006 1.2 -
1014 1.2
LOAD COMB 220 COMBINATION LOAD CASE 220
1001 1.2 1004 1.2 1019 1.6 1003 1.0 1007 -1.2 1008 -1.2 1005 -1.2 1006 -1.2 -
1014 1.2
* 1d. 1.2 (Ds + Do + Ff + T + Af) + 1.6S + 0.5W
LOAD COMB 221 COMBINATION LOAD CASE 221
1001 1.2 1004 1.2 1019 0.0 1003 0.0 1007 1.2 1008 1.2 1005 1.2 1006 1.2 -
1013 1.2 1015 0.5
LOAD COMB 222 COMBINATION LOAD CASE 222
1001 1.2 1004 1.2 1019 0.0 1003 0.0 1007 1.2 1008 -1.2 1005 1.2 1006 -1.2 -
1013 1.2 1015 0.5
LOAD COMB 223 COMBINATION LOAD CASE 223
1001 1.2 1004 1.2 1019 0.0 1003 0.0 1007 -1.2 1008 1.2 1005 -1.2 1006 1.2 -
1013 1.2 1015 -0.5
LOAD COMB 224 COMBINATION LOAD CASE 224
1001 1.2 1004 1.2 1019 0.0 1003 0.0 1007 -1.2 1008 -1.2 1005 -1.2 1006 -1.2 -
1013 1.2 1015 -0.5
LOAD COMB 225 COMBINATION LOAD CASE 225
1001 1.2 1004 1.2 1019 0.0 1003 0.0 1007 1.2 1008 1.2 1005 1.2 1006 1.2 -
1013 1.2 1016 0.5
LOAD COMB 226 COMBINATION LOAD CASE 226
1001 1.2 1004 1.2 1019 0.0 1003 0.0 1007 1.2 1008 -1.2 1005 1.2 1006 -1.2 -
1013 1.2 1016 -0.5
LOAD COMB 227 COMBINATION LOAD CASE 227
1001 1.2 1004 1.2 1019 0.0 1003 0.0 1007 -1.2 1008 1.2 1005 -1.2 1006 1.2 -
1013 1.2 1016 0.5
LOAD COMB 228 COMBINATION LOAD CASE 228
1001 1.2 1004 1.2 1019 0.0 1003 0.0 1007 -1.2 1008 -1.2 1005 -1.2 1006 -1.2 -
1013 1.2 1016 -0.5
*****************************************************************************
LOAD COMB 229 COMBINATION LOAD CASE 229
1001 1.2 1004 1.2 1019 1.6 1003 0.0 1007 1.2 1008 1.2 1005 1.2 1006 1.2 -
1014 1.2 1015 0.5
LOAD COMB 230 COMBINATION LOAD CASE 230
1001 1.2 1004 1.2 1019 1.6 1003 0.0 1007 1.2 1008 -1.2 1005 1.2 1006 -1.2 -
1014 1.2 1015 0.5
LOAD COMB 231 COMBINATION LOAD CASE 231
1001 1.2 1004 1.2 1019 1.6 1003 0.0 1007 -1.2 1008 1.2 1005 -1.2 1006 1.2 -
1014 1.2 1015 -0.5
LOAD COMB 232 COMBINATION LOAD CASE 232
1001 1.2 1004 1.2 1019 1.6 1003 0.0 1007 -1.2 1008 -1.2 1005 -1.2 1006 -1.2 -
1014 1.2 1015 -0.5
LOAD COMB 233 COMBINATION LOAD CASE 233
1001 1.2 1004 1.2 1019 1.6 1003 0.0 1007 1.2 1008 1.2 1005 1.2 1006 1.2 -
1014 1.2 1016 0.5
LOAD COMB 234 COMBINATION LOAD CASE 234
1001 1.2 1004 1.2 1019 1.6 1003 0.0 1007 1.2 1008 -1.2 1005 1.2 1006 -1.2 -
1014 1.2 1016 -0.5
LOAD COMB 235 COMBINATION LOAD CASE 235
1001 1.2 1004 1.2 1019 1.6 1003 0.0 1007 -1.2 1008 1.2 1005 -1.2 1006 1.2 -
1014 1.2 1016 0.5
LOAD COMB 236 COMBINATION LOAD CASE 236
1001 1.2 1004 1.2 1019 1.6 1003 0.0 1007 -1.2 1008 -1.2 1005 -1.2 1006 -1.2 -
1014 1.2 1016 -0.5
* 2a. 1.2 (Ds + Do +Af) + 1.0W + L + 0.5S
LOAD COMB 237 COMBINATION LOAD CASE 237
1001 1.2 1004 1.2 1019 0.5 1003 1.0 1005 1.2 1006 1.2 1015 1.0
LOAD COMB 238 COMBINATION LOAD CASE 238
1001 1.2 1004 1.2 1019 0.5 1003 1.0 1005 1.2 1006 -1.2 1015 1.0
LOAD COMB 239 COMBINATION LOAD CASE 239
1001 1.2 1004 1.2 1019 0.5 1003 1.0 1005 -1.2 1006 1.2 1015 -1.0
LOAD COMB 240 COMBINATION LOAD CASE 240
1001 1.2 1004 1.2 1019 0.5 1003 1.0 1005 -1.2 1006 -1.2 1015 -1.0
LOAD COMB 241 COMBINATION LOAD CASE 241
1001 1.2 1004 1.2 1019 0.5 1003 1.0 1005 1.2 1006 1.2 1016 1.0
LOAD COMB 242 COMBINATION LOAD CASE 242
1001 1.2 1004 1.2 1019 0.5 1003 1.0 1005 1.2 1006 -1.2 1016 -1.0
LOAD COMB 243 COMBINATION LOAD CASE 243
1001 1.2 1004 1.2 1019 0.5 1003 1.0 1005 -1.2 1006 1.2 1016 1.0
LOAD COMB 244 COMBINATION LOAD CASE 244
1001 1.2 1004 1.2 1019 0.5 1003 1.0 1005 -1.2 1006 -1.2 1016 -1.0
* 2b. (1.2+0.2SDS) (Ds + Do) +1.2Af + 1.0Eo + L + 0.2S
LOAD COMB 245 COMBINATION LOAD CASE 245
1001 1.376 1004 1.376 1019 0.2 1003 1.0 1005 1.2 1006 1.2 1017 1.0 1018 0.3
LOAD COMB 246 COMBINATION LOAD CASE 246
1001 1.376 1004 1.376 1019 0.2 1003 1.0 1005 1.2 1006 -1.2 1017 1.0 -
1018 -0.3
LOAD COMB 247 COMBINATION LOAD CASE 247
1001 1.376 1004 1.376 1019 0.2 1003 1.0 1005 -1.2 1006 1.2 1017 -1.0 -
1018 0.3
LOAD COMB 248 COMBINATION LOAD CASE 248
1001 1.376 1004 1.376 1019 0.2 1003 1.0 1005 -1.2 1006 -1.2 1017 -1.0 -
1018 -0.3
LOAD COMB 249 COMBINATION LOAD CASE 249
1001 1.376 1004 1.376 1019 0.2 1003 1.0 1005 1.2 1006 1.2 1017 0.3 1018 1.0
LOAD COMB 250 COMBINATION LOAD CASE 250
1001 1.376 1004 1.376 1019 0.2 1003 1.0 1005 1.2 1006 -1.2 1017 0.3 -
1018 -1.0
LOAD COMB 251 COMBINATION LOAD CASE 251
1001 1.376 1004 1.376 1019 0.2 1003 1.0 1005 -1.2 1006 1.2 1017 -0.3 -
1018 1.0
LOAD COMB 252 COMBINATION LOAD CASE 252
1001 1.376 1004 1.376 1019 0.2 1003 1.0 1005 -1.2 1006 -1.2 1017 -0.3 -
1018 -1.0
* 3. 0.9 Ds + 0.9 (De or 0.6 Do) + 1.0W
LOAD COMB 253 COMBINATION LOAD CASE 253
1001 0.9 1002 0.9 1015 1.0
LOAD COMB 254 COMBINATION LOAD CASE 254
1001 0.9 1002 0.9 1015 -1.0
LOAD COMB 255 COMBINATION LOAD CASE 255
1001 0.9 1002 0.9 1016 1.0
LOAD COMB 256 COMBINATION LOAD CASE 256
1001 0.9 1002 0.9 1016 -1.0
* 4. (0.9-0.2SDS) (Ds + Do) + 1.2Af + 1.0Eo
LOAD COMB 257 COMBINATION LOAD CASE 257
1001 0.724 1004 0.724 1005 1.2 1006 1.2 1017 1.0 1018 0.3
LOAD COMB 258 COMBINATION LOAD CASE 258
1001 0.724 1004 0.724 1005 1.2 1006 -1.2 1017 1.0 1018 -0.3
LOAD COMB 259 COMBINATION LOAD CASE 259
1001 0.724 1004 0.724 1005 -1.2 1006 1.2 1017 -1.0 1018 0.3
LOAD COMB 260 COMBINATION LOAD CASE 260
1001 0.724 1004 0.724 1005 -1.2 1006 -1.2 1017 -1.0 1018 -0.3
LOAD COMB 261 COMBINATION LOAD CASE 261
1001 0.724 1004 0.724 1005 1.2 1006 1.2 1017 0.3 1018 1.0
LOAD COMB 262 COMBINATION LOAD CASE 262
1001 0.724 1004 0.724 1005 1.2 1006 -1.2 1017 0.3 1018 -1.0
LOAD COMB 263 COMBINATION LOAD CASE 263
1001 0.724 1004 0.724 1005 -1.2 1006 1.2 1017 -0.3 1018 1.0
LOAD COMB 264 COMBINATION LOAD CASE 264
1001 0.724 1004 0.724 1005 -1.2 1006 -1.2 1017 -0.3 1018 -1.0
* 5. 1.4 (Ds + Dt)
LOAD COMB 265 COMBINATION LOAD CASE 265
1001 1.4 1009 1.4
* 6. 1.2 (Ds + Dt) + 0.5W
LOAD COMB 266 COMBINATION LOAD CASE 266
1001 1.2 1009 1.2 1015 0.5
LOAD COMB 267 COMBINATION LOAD CASE 267
1001 1.2 1009 1.2 1015 -0.5
LOAD COMB 268 COMBINATION LOAD CASE 268
1001 1.2 1009 1.2 1016 0.5
LOAD COMB 269 COMBINATION LOAD CASE 269
1001 1.2 1009 1.2 1016 -0.5
PERFORM ANALYSIS PRINT ALL
DEFINE ENVELOPE
101 TO 172 ENVELOPE 1 TYPE SERVICEABILITY
201 TO 269 ENVELOPE 2 TYPE STRENGTH
END DEFINE ENVELOPE
**************************************************************************************************
** DESIGN FACTOR**
**************************************************************************************************
**Strength check**
PARAMETER 1
CODE AISC UNIFIED 2010
METHOD LRFD
CB 0 ALL
FU 400000 ALL
FYLD 250000 MEMB 329 TO 331 334 TO 336 339 TO 341 344 TO 346 349 TO 393
FYLD 290000 MEMB 332 333 337 338 342 343 347 348 394 TO 409
KY 1 MEMB 329 330 334 335 339 340 344 345
KZ 2 MEMB 329 330 334 335 339 340 344 345
LZ 9.35 MEMB 350 354 358 359 361 362 364 365 367 368 370 371 373 374 376 377 -
379 380 382 383
LZ 3.95 MEMB 351 352 385 386 388 389 391 392
LZ 1.8 MEMB 349 353 355 356
LOAD LIST 201 TO 269
CHECK CODE ALL
**Deflection check**
PARAMETER 2
CODE AISC UNIFIED 2010
METHOD LRFD
DFF 900 MEMB 331 336 341 346 349 TO 393
UNB 1.8 MEMB 349 353 355 356
UNT 1.8 MEMB 349 353 355 356
DJ2 249 MEMB 354 358 361 364 367 370 373 376 379 382
DJ1 245 MEMB 354 358 361 364 367 370 373 376 379 382
DJ2 251 MEMB 350 359 362 365 368 371 374 377 380 383
DJ1 247 MEMB 350 359 362 365 368 371 374 377 380 383
DJ2 245 MEMB 353 355
DJ1 241 MEMB 353 355
DJ2 247 MEMB 349 356
DJ1 243 MEMB 349 356
DJ2 253 MEMB 352 385 388 391
DJ1 249 MEMB 352 385 388 391
DJ2 255 MEMB 351 386 389 392
DJ1 251 MEMB 351 386 389 392
LOAD LIST 101 TO 172
CHECK CODE MEMB 331 336 341 346 349 TO 393 349 353 355 356 -
354 358 361 364 367 370 373 376 379 382 350 359 362 365 368 -
371 374 377 380 383 353 355 349 356 352 385 388 391 351 386 389 392
****
FINISH

Serviceability load cases 101 to 172 have been used for deflection check & Strength loadcases are 201-269.

Result for Unity Check show item such as

349 W6X16 W6X16  0.089  1.000  0.089 Eq. H1-1b    130  30.581  1336.103  183.142  9.157

where Eq. H1-1b    loadcase 130   is a seviceability load case associated with a strength check which is incorrect as no stregth check were expected to be critical for the 101-172 loadcases.

Can any one explain why I am getting such result. Thanks

Deal All,

On structure that I'm working on I have a 11,6m beam which supports transverse beams and bracing.

How can I determine the overall deflection of the 11.6 m beam and check if it is complying with the L/500 criteria?

The only result that I can get so far is the deflection on nodes or section displacement (Beam length between 2 nodes).

Of course I could track every node displacement, but on a complex structure with several long beams and many nodes, I think there must be a better solution.

I welcome your comments.

Thanks in advance.

1. Download the file OpenStaadRegistrationChecker.zip from here

2. Unpack the archived folder to any location on your machine (desktop for example)

3. Go to folder C:\SProV8i\STAAD\Plugins\StrucLink and copy file StrucLink.exe.config

4. Paste this file to the folder OpenStaadRegistrationChecker which You unpacked on your desktop

5. Then right click on the file OpenStaad.Registration.exe in that folder and select option Run as Administrator

6. Once this is done click on the button Check OpenSTAADUI. This will confirm if the openSTAADUI library is registered or not.

7. If it is not registered, then click the button Register OpenSTAADUI

Why is RAM Concept opening in trial mode even though my licensing is current?

Currently Ram Concept is sold with one optional add-on called the Ram Concept Post tension Module. Without it you can still use the program to analyze and design Concrete slabs and mat foundations that are mild reinforced,
but if the slab is to have post tensioning in it, the Ram Concept Post Tension license is required.

When RAM Concept is first installed on a computer, it contains a built-in 15-day trial period. This trial period is activated only when it fails to retrieve licenses for both RAM Concept and RAM Concept Post Tension. If your contract does not have a license for post tension (or if the post tension license is currently unavailable), the trial period will be activated to provide temporary access to the post tension features. Once the trial period has expired, the program will open without a trial period message and disable the post tension features.

When opening STAAD.Pro, why do I receive a "Valid Trial License was not found or trial license expired, entering limited mode..." message even though I have licenses?

Visit FAQ ON STAAD LICENSE - USL versus STANDARD to resolve this issue.

Why do I receive Copy Protection errors in STAAD.Pro?

STAAD.Pro must have a license for the design code(s) used in a model. The error message indicates that a license for the needed design code was not retrieved. To configure what licenses STAAD.Pro retrieves when starting, open the program, locate the License Configuration section on the opening screen, and ensure that the needed design codes have checkmarks next to them. A green light next to a checked design code indicates that a license was found.

Why does the Activation Status window in the License Management Tool indicate that my product will expire in x days even though I have a license?

The Activation Status window of the License Management Tool is useful for quickly determining the license status of Bentley products that utilize "trust licensing." Trust licensing products periodically report to the license server as they are used. Because such products must report to the server at least every 30 days, the Activation Status quickly shows how much time remains. RAM, STAAD, and AutoPIPE products, however, utiliize licenses differently. Licenses are temporarily locked to a workstation each time such a product is used. Consequently, the activation status for these products will appear as a trial period when not in use. The activation status for RAM, STAAD, and AutoPIPE products can be safely ignored. The products will display licensing errors when opened if a license-related problem exists.

If I lose my network connection, am I denied access to my programs?

Structural products must retrieve licenses from a license server each time they are opened. However, in the event that the license server cannot be reached (i.e. network outage), the licensing software installed on client machines provides a fallback mechanism for accessing products. This fallback mechanism, called the “grace period,” provides access to licensed products for up to four days. The licensing software keeps a list of which products have been accessed within the last 30 days. If a product attempts to retrieve a license but is unable to reach the server, the grace period is activated for this license if found in the list. The license can be used in the grace period for up to four days from the first unsuccessful attempt. Once a license is retrieved successfully from the server again, the timer is reset.

For example, suppose I have licenses for RAM Modeler and RAM Steel, modules for RAM Structural System. As long as I have used both of these licenses within the last 30 days, the grace period will be activated for either of these licenses in the event that I cannot reach the license server. I can use these licenses for up to four days without access to the server. Once access to the server is restored, the grace period will be reset. That way, should I lose connection to the server again in the future, I will have up to four days to use my licenses apart from a connection.

Why does my program fail to return licenses when closing?

This issue may indicate an installation-related problem with the Bentley IEG License Service, a licensing component that retrieves and returns licenses on behalf of RAM, STAAD, AutoPIPE, SACS, and FormSys products. For troubleshooting purposes, please perform the following steps:

1. Visit the Add or Remove Programs (Windows XP) or Programs and Features (Windows Vista/7/8) control panel, and remove any listings for Bentley IEG License Service.
2. Reinstall the Bentley IEG License Service. A standalone alone installer for the component (named iegls02002001en.msi) is listed as a dependency for most of the products. Re-run this installer to reinstall the Bentley IEG License Service. SACS users on 64-bit operating systems will have two licensing dependencies: Bentley IEG License Service and Bentley IEG License Service x64. Run both installers in this case.
   For RAM Structural System and STAAD products, the installer is included in the product installer itself. In these cases, re-run the product installer to reinstall the component.

The issue may also be caused by a communication problem with the license server. Computers can be configured to communicate with the license server using an alternate protocol as a troubleshooting step. To do this:

1. Open the License Management Tool.
2. Select Options from the Tools menu.
3. Toggle the "Use HTTPS (SSL)" checkbox.
4. Click the Test Connection button.
5. If the server name and site activation key verify, click OK to save changes. Otherwise, click the Cancel button.

See Also

Structural Product TechNotes and FAQs

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

Comments or Corrections?

Bentley's Technical Support Group requests that you please submit any comments you have on this Wiki article in the "Comments" area below. THANK YOU!

1. While I can look at the model with Stress Ratio values annotated next to the steel members that I have asked to be checked, when I do the member query (double clicking on the members) I don't see the Design Property and Steel Design boxes anymore. Why is that?
2. STAAD is checking deflection for beams or girders for all the load combinations in my model. Is there a way to tell STAAD which load combination to check?
3. The steel design output indicates a slenderness failure (KL/r exceeds allowable). Why? The axial force on the member is very small.
4. I set my deflection limit to L/360, but the maximum deflection indicated in the summary of node displacements in PostProcessing shows a deflection of 1.5 inches. Isn't this above the limit that I set?
5. THE VALUE OF E FOR MEMBER NNN DOES NOT SEEM RIGHT. What does this mean?
6. The KL/r value that STAAD reports for the Y axis for a single angle does not match what I get from my hand calculation. Can you explain why?
7. I have a large model with several hundred members which have been assigned steel sections. I am doing a code check and I want to find out which of those members have failed. Can I get a list of just those members without having to scroll through hundreds of pages of steel design output?
8. I am running STAAD.Pro 2003. In the TRACK 2 output for the American LRFD code, I find some terms that I am not familiar with. Can you tell me what those are?
9. I am running STAAD.Pro 2002. In the TRACK 2 output for the AISC ASD code, I find some terms that I am not familiar with. Can you tell me what those are?
10. I am using STAAD.Pro 2003 and I want to use physical members to do a steel design. I know how to manually create physical members by selecting the individual members, right-clicking the mouse and choosing Form Member. But if I have hundreds of these members, can I do it faster?
11. I want STAAD.Pro to perform a steel design based on the LRFD 3rd Ed rather than the 2nd Edition. The output always says "LRFD 1994". How do I tell it what code to use?
12. I am not sure how STAAD deals with the specifications of the unsupported length for top flange compression.
13. I would like to perform code checking on a 8" x 2 1/2" x 10 Gage channel per the AISI Coldformed steel code. But this channel is not listed in the sections available in your database. Can I assign it using a user provided table?
14. Increasing the NSF value in Steel Design does not change the Failure Ratio for a member, Why?
15. I ran my STAAD model and got an error message which stated that "This version does not design prismatic sections". What does this mean?
16. The KL/ry reported for a double angle does not match my hand calculations. I am designing the section per the AISC ASD 9th edition code.
17. I am using the composite beam design capabilities. But the output does not show any evidence of this design. Why?
18. How does one change the value of the yield strength of steel?
19. In STAAD/Pro 2000 and STAAD.Pro, I no longer see the UNL parameter for the AISC ASD and LRFD codes. Instead, I see the parameters UNT and UNB. Why?
20. The steel design output for a tube section checked per the AISC ASD code indicates an SY and SZ substantially different from the values which are reported in the AISC publication. Why?
21. How can I check whether the story drift of the floors are within allowable limits?
22. Utilizing DFF in STAAD only helps one check the local deflection. What if I want to check the drift of a column / beam frame?
23. Can I get STAAD to check deflection in both axes?
24. Will STAAD explicitly state that the beam has passed the deflection criteria?
25. What are the design parameters which control deflection check?
26. THIS VERSION DOES NOT DESIGN TAPERED POLE SECTIONS (MEMBER 1). What does this error message mean?
27. I am using STAAD to do steel design per the AISC code. For 2 members with similar cross sections, one passes, the other fails. Fact is, the one which fails has almost no load on it. The other is significantly more stressed but still passes. Is something wrong in the steel design calculations that STAAD is doing?
28. What do the following parameters mean? NSF 0.85 ALL, BEAM 1.0 ALL, KY 1.2 ALL, RATIO 0.9 ALL, LY 18 ALL, LZ 18 ALL, CHECK CODE ALL
29. When one does the AISC code check or member selection, what are the calculations the program is performing?
30. When I run code checking [as per BS5950] of the steel prismatic members which were defined in the User Provided Table, I get the following message in my output file:
    DESIGN NOT PERFORMED WITH PRISMATIC PROPERTIES
    USER-TABLE MAY BE USED TO DESIGN PRISMATIC SECTIONS
31. I am using STAAD to perform steel design on a member per the AISC ASD code. I want the column to be designed based on an unbraced length of 20 ft. I have set the UNT and UNB values to 20 ft, but STAAD appears to consider only a 10 feet length in its KL/r calculations. How do I correct this problem?
32. How do I get a design parameter, say the RATIO parameter, to be applied only to certain load cases?
33. I run the analysis of a 3-D bridge truss model and requested a CODE CHECK of the members. The results of this code check do not correspond to my hand calculation results.
34. What is the LX parameter used for?
35. The KL/r value that STAAD reports for a single angle member does not match my hand calculation. Design is per the AISC ASD 9th edition code.
36. What are the SSY and SSZ parameters for AISC ASD based steel design?
37. The KL/ry reported for a T shape does not match my hand calculations. I am designing the section per the AISC ASD 9th edition code.
38. Can you provide me with some help on how I can include deflection check as one of the criteria in steel design?
39. In the output for steel design, what does the term "dff" represent?
40. In STAAD-III, I was able to get a steel design for members defined using the PRISMATIC property attribute per the AISC ASD code. I cannot do this in STAAD/Pro. Why?
41. In the context of design, what is meant by the term Ratio?
42. I have multiple sets of design in the same STAAD file and I am only able to see the results for the final set in the Postprocessing mode (GUI). How can I view the results for all design sets in the GUI ?
43. How is the shear stress calculated in STAAD.Pro for AISC design code ?
44. Do you have a plan that STAAD.Pro implements AISI 2007 edition?
45. A structure that I'm working on I have a 11.6m beam which supports transverse beams and bracing. How can I determine the overall deflection of the 11.6 m beam and check if it is complying with the L/500 criteria?

1. While I can look at the model with Stress Ratio values annotated next to the steel members that I have asked to be checked, when I do the member query (double clicking on the members) I don't see the Design Property and Steel Design boxes anymore. Why is that?

 Design Property and Steel Design tabs are not displayed for members which have not been designed. Are you sure you are clicking a member for which the design has been done? Sometimes, when ratios are annotated on the screen, the picture may become quite cluttered with data and in an effort to double click on a designed member, one may end up clicking on a member for which design has not been performed. So, first check that the member you are double-clicking has indeed been designed. If you are certain that STAAD has done the design and evidence of that exists in the analysis output file and in the postprocessing Unity Check tables, but still you are not able to see these tabs in the dialog box which comes up when you double click on the member, please send us your .std model and our support representatives will look into that.

2. STAAD is checking deflection for beams or girders for all the load combinations in my model. Is there a way to tell STAAD which load combination to check?

You have to use the LOAD LIST command to achieve this. Supposing you want to check deflection for combination cases 81 and 82. And assume that L/Deflection has a limit of 240. The command sequence required to achieve this is

LOAD LIST 81 82
PARAMETER
CODE AISC
DFF 240 ALL
CHECK CODE ALL

However, after these commands, you have to reset DFF to a very small number so that deflection does not become a criteria for any further design operations. That is because, once a parameter is specified in STAAD, it stays that way till it is changed again. So, after the above, you need to specify

PARAMETER
CODE AISC
DFF 1 ALL

3. The steel design output indicates a slenderness failure (KL/r exceeds allowable). Why? The axial force on the member is very small.

The code has requirements which say that the KL/r ratios for a member should not exceed certain allowable limits. For members subjected to tensile forces, the code suggests one limit, and for members subjected to compressive forces, there is another limit.

This check does not consider the amount of the axial force. It only looks at the sign of the force to determine if it is a tensile force or compressive force.

In most codes, this is the first check STAAD does on a member. If the member fails the check, no further calculations are done for that member.

So, STAAD performs these checks by default. However, the code does not offer any guidelines on what must be the minimum magnitude of the axial force for the member to become a candidate for this check.

So, in STAAD, two parameters are available - one called MAIN and another called TMAIN if you wish to bypass this check (TMAIN is available for some codes only). MAIN=1 is for bypassing the slenderness check in compression, and TMAIN=1 is for bypassing the slenderness check in tension.

4. I set my deflection limit to L/360, but the maximum deflection indicated in the summary of node displacements in PostProcessing shows a deflection of 1.5 inches. Isn't this above the limit that I set?

During steel design per the AISC ASD code, there are two types of deflection checks you can perform with STAAD. They are

1. Check for local deflection. This is usually applicable to members which are connected at both their ends to other members.
2. Check for the relative displacements between the nodes such as for a cantilever beam.

LOCAL DEFLECTION is defined as the maximum deflection between the 2 ends of the beam relative to a straight line connecting the 2 ends of that member in its deflected position.

If you go to

Help - Contents - Technical Reference - Commands and Input Instructions - Printing Section Displacements for Members

you will find a diagram indicating this is in figure 5.41.

To obtain more information on the difference between the 2 methods of deflection checking, please go to

Help - Contents - Technical Reference - American Steel Design - Design Parameters (which comes after Allowables per AISC code)

It will bring up section "2.4 Design Parameters"

At the end of the parameters table, you will see several notes. Please read Notes items 1 through 4 for the description of the two methods.

As you can see there, the default condition, which is also represented by a value of zero for the CAN parameter, is to perform the LOCAL DEFLECTION check.

Your question indicates that what you are looking for is a check of the nodal deflections. The cantilever style check STAAD offers is probably the solution for your problem. If so, specify the CAN parameter with a value of 1.

5. THE VALUE OF E FOR MEMBER NNN DOES NOT SEEM RIGHT. What does this mean?

The steel design output for several members is accompanied by the following warning message :

WARNING : THE VALUE OF E FOR MEMBER 21 DOES NOT SEEM RIGHT.

WARNING : THE VALUE OF E FOR MEMBER 22 DOES NOT SEEM RIGHT.

WARNING : THE VALUE OF E FOR MEMBER 23 DOES NOT SEEM RIGHT.

During steel design, there is a check for ensuring that the Modulus of Elasticity (E) specified for the member is within the range that is normal for steel. This is because, E is a crucial term that appears in many equations for calculating section capacities and the program wants you to know if the value appears to be abnormal.

In STAAD, you specify E either explicitly under the CONSTANTS command block or through the DEFINE MATERIAL block, as in the examples below.

Example 1 :

UNIT KIP INCH
CONSTANTS
E 29000 ALL
DENSITY 0.283E-3 ALL

Example 2 :

UNIT METER KNS
DEFINE MATERIAL START
ISOTROPIC STEEL
E 2.05e+008
POISSON 0.3
DENSITY 76.8195
ALPHA 1.2e-005
DAMP 0.03
END DEFINE MATERIAL
CONSTANTS
MATERIAL STEEL MEMBER 101 TO 121

So, if you are specifying an E value which is significantly different from that for steel, such as say, Aluminum, and then later asking the member to be designed according to a steel code, as in the following example, the above-mentioned warning message will appear.

UNIT FEET POUND
DEFINE MATERIAL START
ISOTROPIC ALUMINUM
E 1.44e+009
POISSON 0.33
DENSITY 169.344
ALPHA 1.28e-005
DAMP 0.03
END DEFINE MATERIAL

CONSTANTS
MATERIAL ALUMINUM MEMBER 21 TO 30

..
..
PARAMETER
CODE AISC
CHECK CODE MEMBER 21 TO 30

6. The KL/r value that STAAD reports for the Y axis for a single angle does not match what I get from my hand calculation. Can you explain why? 

For single angles, the local Y and Z axes are the principal axes as shown below:

The KL/r value is computed using ry and rz which are based on the principal axis system. Chances are that your handculation uses the geometric axes.

7. I have a large model with several hundred members which have been assigned steel sections. I am doing a code check and I want to find out which of those members have failed. Can I get a list of just those members without having to scroll through hundreds of pages of steel design output?

There are 2 methods for finding just those members which have failed the steel design checks.

1. From the Select menu, choose By Specification - All Failed beams. The members which fail the check will be highlighted. You can then isolate them into a New View to examine them in greater detail. Double click on those members or use Tools - Query - Member to access a dialog box with tabs called Steel Design and Design Property to see the cause of the failure along with allowable and actual stresses and critical conditions.
2. In the Post processing mode, go to the Beam page along the left side of the screen. One of the sub-pages will be Unity Check. A table will appear along the right side of the screen. One of the tabs of that table is Failed Members. Select this tab, and click on each row of the table to look at each such member individually.

8. I am running STAAD.Pro 2003. In the TRACK 2 output for the American LRFD code, I find some terms that I am not familiar with. Can you tell me what those are?

The terms reported in the TRACK 2 output for American LRFD are :

AX = Cross section Area.
AY : Area used in computing shear stresses along local Y axis.
AZ : Area used in computing shear stresses along local Z axis.
PY : Plastic Section modulus about local Y axis.
PZ : Plastic Section modulus about local Z axis.
RY : Radius of gyration about local Y axis.
RZ : Radius of gyration about local Z axis.

PNC : Axial compression capacity.

pnc : Axial compressive force used in critical condition.

PNT : Axial tensile capacity.

pnt : Axial tensile force used in critical condition.

MNZ : Nominal bending capacity about local Z axis.

mnz : Bending moment about local Z axis, used in critical condition.

MNY : Nominal bending capacity about local Y axis.

mny : Bending moment about local Y axis, used in critical condition.

VN : Shear capacity.

vn : Shear force associated with critical load case and section location.

DFF : Permissible limit for checking length to deflection ratio.

dff : Actual length to deflection ratio.

9. I am running STAAD.Pro 2002. In the TRACK 2 output for the AISC ASD code, I find some terms that I am not familiar with. Can you tell me what those are?

The terms reported in the TRACK 2 output for AISC ASD are :

AX = Cross section Area
AY : Area used in computing shear stresses along local Y axis
AZ : Area used in computing shear stresses along local Z axis
SY : Elastic Section modulus about local Y axis
SZ : Elastic Section modulus about local Z axis
RY : Radius of gyration about local Y axis
RZ : Radius of gyration about local Z axis

FA : Allowable axial stress. If failure condition involves axial tension, this is the allowable axial tensile stress. If failure condition involves axial compression, this is the allowable axial compressive stress.

fa : Actual axial stress.

FCZ : Allowable bending compressive stress about local Z axis.

FTZ : Allowable bending tensile stress about local Z axis.

FCY : Allowable bending compressive stress about local Y axis

FTY : Allowable bending tensile stress about local Y axis.

fbz : Actual bending stress about local Z axis, used in the design condition

fby : Actual bending stress about local Y axis, used in the design condition.

FV : Allowable shear stress.

Fey : Euler stress for buckling about local Y axis.

Fez : Euler stress for buckling about local Z axis.

DFF : Permissible limit for checking length to deflection ratio.

dff : Actual length to deflection ratio.

10. I am using STAAD.Pro 2003 and I want to use physical members to do a steel design. I know how to manually create physical members by selecting the individual members, right-clicking the mouse and choosing Form Member. But if I have hundreds of these members, can I do it faster?

In STAAD.Pro 2003, you can use the Auto-Form member option to let the program automatically create physical members for you. From the Member Design page in the Steel Design Mode, go to Member Design | Physical Members | Auto Form Members. The rules it uses to create physical members are as follows:

1. All elements must form a single continuous line. But they do not have to form a straight line. Thus curved members may be formed.
2. There must be a free end. Whilst curved members are allowed, they cannot form a closed loop.
3. All elements should have the same beta angle.
4. All elements must point in the same direction. Check with the orientation labels if necessary. Use the reverse element command on elements that point the wrong way.
5. None of the elements can be part of another member.
6. The section properties must be consistent at each element end. Elements can taper along their length, but where one element ends and the next starts, they must have the same section reference.
7. All elements must be made from the same material.
8. Vertical segments are converted into columns first.

11. I want STAAD.Pro to perform a steel design based on the LRFD 3rd Ed rather than the 2nd Edition. The output always says "LRFD 1994". How do I tell it what code to use?

If you wish to use LRFD 3rd Edition Code, you can write CODE LRFD3 when providing the design parameters.

The 3rd edition of the American LRFD steel code has been implemented along with the 2nd edition. In general, the principles outlined in the code for design for axial tension, compression, flexure, shear etc., are quite similar to those in earlier versions of the code. The major differences are in the form of incorporation of the Young’s modulus of steel in the various equations for determining various limits like slenderness and capacities.


Consequently, the general procedure used in STAAD for design of steel members per the AISC-LRFD code has not changed significantly. Users may refer to Section 2 of the STAAD.Pro Technical Reference manual for these procedures.


Those who wish to use the 1994 edition of the code can still do so by specifying the code name as:

CODE LRFD2

An example of commands used for performing design based on the new and old codes are as shown.


Example for the LRFD-2001 code (3rd Ed)


UNIT KIP INCH
PARAMETER
CODE LRFD


or

CODE LRFD3
FYLD 50 ALL
UNT 72 MEMBER 1 TO 10
UNB 72 MEMB 1 TO 10
MAIN 1.0 MEMB 17 20
SELECT MEMB 30 TO 40
CHECK CODE MEMB 1 TO 30

Example for the LRFD-1994 code (2nd Ed)

UNIT KIP INCH
PARAMETER
CODE LRFD2
FYLD 50 ALL
UNT 72 MEMBER 1 TO 10
UNB 72 MEMB 1 TO 10
MAIN 1.0 MEMB 17 20
SELECT MEMB 30 TO 40
CHECK CODE MEMB 1 TO 30

12. I am not sure how STAAD deals with the specifications of the unsupported length for top flange compression.

For example, if I have a truss whose top chord is laterally supported at every other node (i.e. two member lengths being unsupported), then should I highlight every two members (of the top chord) seperately and then tell the program to take their combined length as being unsupported, or should I highlight the entire top chord and then specify the correct unsupported length.

The value you specify for UNL is what STAAD uses for the expression Lb which you will find in Chapter F of the AISC ASD & LRFD codes. Starting from Version 2001, UNL has been replaced with UNT and UNB for these codes. If the Lb value for the top flange is different from that for the bottom flange, you have to specify the corresponding values for UNT & UNB.

So if the bracing points are at every alternate node, first determine the distance between the alternate nodes. Then assign that value for both beams which exist between those nodes.

For example, if you have

Member 5 connected between nodes 10 and 11, and is 6.5 ft long
Member 6 connected between nodes 11 and 12, and is 7.3 ft long

and both the top and bottom flanges are braced at nodes 10 & 12, you can assign

UNIT FEET
PARAMETER
CODE AISC
UNT 13.8 MEMB 5 6
UNB 13.8 MEMB 5 6

To assign these parameters using the GUI, while in the Modelling mode, select the Design page from the left side of the screen. Make sure the focus is on the Steel sub-page. On the right side, select the proper code name from the list box on the top. Click on the Define Parameters button along the bottom right side. In the dialog box which comes up, select the tab for UNT and UNB, specify the value, and assign it to the appropriate members.

13. I would like to perform code checking on a 8" x 2 1/2" x 10 Gage channel per the AISI Coldformed steel code. But this channel is not listed in the sections available in your database. Can I assign it using a user provided table?

At present, sections whose data is specified using a "User Provided Table" (see section 5.19 of the Technical reference manual for details) cannot be designed or checked per the AISI code. However, the following approach may be used to get around this limitation.

You may add your section to the STAAD AISI section database, so that your section becomes a permanent part of the database. This can be done using the following method.

From the Tools menu, select Modify Section database. The various steel databases available in the program will be listed in a dialog box. You will find ColdFormed (US) at the end of this list. Expand this list, and choose Channel with Lips or Channel without Lips as the case may be. On the right half of the dialog box, the Add option will become activated. Select that, and you will now be provided with an interface through which you can add your channel to the list. Save and Close it.

You can now go to the Commands menu, and choose Member property - Steel Table - AISI Table to obtain visual confirmation that this new section is permanently included among the list of channel sections. You should now be able to assign this new section to the members through the usual property pages and menus.

14. Increasing the NSF value in Steel Design does not change the Failure Ratio for a member, Why?

In the design input parameters, I set NSF to .85 for my steel design. The design output result showed a failure ratio of 1.063 on Member 1. I then proceeded to change the NSF parameter to 1.0. This time, the design output result showed the same failure ratio of 1.063. It seems that nothing has changed. I increased the net section factor by 0.15, but the stress ratio hasn't changed? 

The NSF value has an effect only on allowable axial tensile capacity, and the actual tensile stress.

If axial tension, or axial tension plus bending, are not what determine the critical condition, changing the value of NSF will not have any impact on the failure ratio. For example, if the critical failure condition for a member is compression, changing NSF will have no impact.

Check to see what the critical condition is. It will show up in the form of expressions such as:

AISC H1-1 or Slenderness, etc.

15. I ran my STAAD model and got an error message which stated that "This version does not design prismatic sections". What does this mean?

In the earlier versions of STAAD (STAAD-III), the code check for prismatic sections was done using allowable stresses which are arbitrarily chosen as 0.6 x Fy. However, this assumption of 0.6Fy was not based on any code specific requirements. The word PRISMATIC is meant to indicate a section of any arbitrary shape. But neither the AISC nor LRFD codes provide guidelines for design of arbitrary shapes. Section capacities are dependent upon aspects such as the width to thickness ratio of flanges and webs, lateral torsional buckling etc. From that standpoint, using an allowable stress of 0.6Fy for PRISMATIC sections was not always conservative.

A way around this limitation (lack of specific guidelines) would have been to use the rules of a known shape, such as a Wide Flange, for designing prismatic shapes. That would require knowledge of equivalent flange and web dimensions. When the properties are defined using the PRISMATIC option, there is no means to convey information such as dimensions of flanges or webs to the STAAD design facility. Hence, the design of PRISMATIC shapes is not supported in STAAD/Pro. You may get around this problem by defining the properties using the GENERAL section in a User Provided Table. For a GENERAL section, STAAD provides the means for providing dimensions of the components that are critical from the standpoint of computing allowable stresses. The allowable stresses for a GENERAL section are computed using the rules of a wide flange shape (I shape). As a result, the allowable stress value will be dependent on attributes such as dimensions of the cross section, length of the member, etc.

16. The KL/ry reported for a double angle does not match my hand calculations. I am designing the section per the AISC ASD 9th edition code.

For singly symmetric shapes such as Tees and Double Angles, the KL/r value for the Y axis is calculated by STAAD using the rules for flexural torsional buckling as explained in page 3-53 of the AISC ASD manual. It is not calculated as Ky multiplied by Ly divided by ry. 

17. I am using the composite beam design capabilities. But the output does not show any evidence of this design. Why?

There are 2 sets of data associated with analysing and designing a composite beam.

Step 1 : Define the member properties as a composite beam. To do this, one has to use the "TA CM" option as explained in Section 5.20.1 of the STAAD.Pro Technical reference Manual. For example, if member 1 is a composite beam made up of a 3.0 inch thick slab on top of a W18X35, and the grade of concrete is 4.0ksi, one would have to specify

UNIT INCH KIP
MEMBER PROPERTIES
1 TA CM W18X35 CT 3.0 FC 4.0

Step 2 : Parameters for steel design. This is what you find in Section 2.9 of the STAAD.Pro Technical reference Manual. These are the attributes which are to be used in the actual design equations, using the expression PARAMETER, as in,

PARAMETER
CODE AISC
BEAM 1 ALL
TRACK 2 ALL
FYLD 50 ALL
CMP 1 ALL
DR1 0.3 ALL
WID 60 ALL
FPC 4 ALL
THK 4 ALL
SHR 0 ALL
DIA 0.75 ALL
HGT 4 ALL
RBH 2 ALL
CHECK CODE ALL

The most important thing to note here is the usage of the parameter CMP. Unless it is set to 1.0, STAAD does not design the beam as a composite section. The beam will be designed as a pure steel beam section in the absence of the "CMP 1" parameter.

18. How does one change the value of the yield strength of steel?

FYLD is one of the items specified as parameters for steel design. The STAAD Technical Reference manual and International Design Codes manual contain information on specifying parameters for steel design.

There are example problems in the STAAD Example manual demonstrating how parameters are specified for design. The example below shows some typical post-analysis commands.

PERFORM ANALYSIS PRINT STATICS CHECK
PRINT MEMBER FORCES LIST 5 7
PRINT ELEMENT STRESSES LIST 10 TO 16
UNIT KIP INCH
PARAMETERS
CODE AISC
UNT 1.0 ALL
UNB 20.0 ALL
LY 60 MEMBER 36 40
LZ 60 MEMBER 36 40
FYLD 46.0 MEMBER 47 50
CHECK CODE ALL
FINISH

If you prefer to use the graphical method, this is how you can specify it. From the left side of the screen, select the Design page. Make sure the sub-page says Steel. On the right hand side of the screen, go to the top, and choose the appropriate code.

Select the members on the structure for which you wish to assign the FYLD parameter.

Then, on the bottom right hand side of the screen, you will find a button called Define Parameters. Click on that button. Select the FYLD tab. Specify the value, and click on Assign.

19. In STAAD/Pro 2000 and STAAD.Pro, I no longer see the UNL parameter for the AISC ASD and LRFD codes. Instead, I see the parameters UNT and UNB. Why?

In versions of STAAD prior to STAAD/Pro 2000, the mechanism for specifying the unsupported length of the compression flange was through the means of the UNL parameter. However, the drawback of this command is that if the value for the top flange is different from that of the bottom flange, there wasn't any means to communicate that information to STAAD.

Consequently, 2 new commands were introduced, namely, UNT and UNB.

UNT stands for the unsupported length of the TOP flange of the member for calculating the capacity in bending compression and bending tension.

UNB stands for the unsupported length of the BOTTOM flange for calculating the capacity in bending compression and bending tension.

To avoid the confusion that may arise from having 3 separate parameters to specify 2 items of input, we no longer mention the UNL parameter. However, to enable the current versions of STAAD to analyze input files created using the older versions of STAAD, the UNL parameter continues to work the way it did.

These 2 new parameters are to be used in place of UNL. If UNT/UNB is specified in addition to UNL, UNL will be ignored. If neither UNT nor UNB are specified, but UNL is specified, the value of UNL will be used for both top and bottom flange.

20. The steel design output for a tube section checked per the AISC ASD code indicates an SY and SZ substantially different from the values which are reported in the AISC publication. Why?

In steel design per the AISC ASD code, the elements of the cross section (flange, web etc.) have to be put through some tests per Chapter B of the code. These tests are required to classify the cross section into one of 3 types - Compact, Non-compact, Slender.

If a section is classified as slender, the allowable stresses on the section have to be determined per the rules of Appendix B of the code. For slender "stiffened elements", which is the type a tube falls into, the effective section properties have to be calculated and those effective properties must then be used in computing the actual stresses.

The extent of the cross section deemed effective depends on the bending moment on that section. It is very likely that for the critical load case, the effective properties are less than the gross section properties, which is why you see the reduced Sz and Sy in the output.

21. How can I check whether the story drift of the floors are within allowable limits?

If you have STAAD.Pro 2001 Build 1005 or Build 1006, you can specify a command called

PRINT STORY DRIFT

in your input file. Run the analysis. Then check your output file, The drift for each story will be reported. You will have to manually verify that this is within your allowable limits.

22. Utilizing DFF in STAAD only helps one check the local deflection. What if I want to check the drift of a column / beam frame?

If my joint displacement printout says that joint of a column/beam joint has moved 1.42 inch in the global X, then my drift ratio is 18x12/1.42 = 152.11, but the "dff" says 1072 for the same column, then where is the dff being measured?

When the DFF parameter is specified, the deflection checks during steel design are performed on the basis of so called "local axis deflection", not the nodal displacements in the global axis. For this reason, it is not possible to include storey drift checks into the steel design calculations at present.

If you want additional information on local axis deflection, please refer to example # 13, and Section 5.42 of the STAAD Technical Reference Manual.

23. Can I get STAAD to check deflection in both axes?

 Yes. However, rather than check the deflection for each axis independently, STAAD finds the resultant deflection "d" and compares the "L/d" (length to deflection ratio) against the allowable limit specified by you through the DFF parameter.

24. Will STAAD explicitly state that the beam has passed the deflection criteria?

When STAAD performs steel design (code checking as well as member selection), it checks several conditions required by the code. The one which gives rise to the highest unity check is the one determined as critical. If the deflection criteria ends up being the worst condition, you will see it being reported as the critical condition.

You can verify whether a member has passed the deflection check by looking at the terms "DFF" and "dff" in the steel design output. "DFF" is the value you input. "dff" is the value the program calculates as the actual "L/d" ratio. If "dff" is larger than "DFF", the member is deemed safe for deflection.

25. What are the design parameters which control deflection check?

1) DFF : This is the value which indicates the allowable limit for L/d ratio. For example, if a user wishes to instruct the program that L/d cannot be smaller than 900, the DFF value should be specified as 900. The default value for DFF is 0. In other words, if this parameter is not specified as an input, a deflection check will not be performed.

2) DJ1 and DJ2 : These 2 quantities affect the "L" as well as the "d" in the calculated L/d ratio. They represent node numbers that form the basis for determining L and d.

By default, DJ1 and DJ2 are the start and end nodes of the member for which the design is being performed, and "L" is the length of the member, namely, the distance between DJ1 and DJ2. However, if that member is a component segment of a larger beam, and the user wishes to instruct STAAD that the end nodes of the larger beam are to be used in the evaluation of L/d, then he/she may input DJ1 and DJ2 as the end nodes of the larger beam. Also, the "d" in L/d is calculated as the maximum local displacement of the member between the points DJ1 and DJ2. The definition of local displacement is available in Section 5.42 of the STAADPro Technical Reference Manual, as well as in Example problem # 13 in the STAADPro Examples Manual.

A pictorial representation of DJ1 and DJ2, as well additional information on these topics is available under the "Notes" section following Table 2.1 in Section 2.8 of the STAADPro Technical Reference Manual.

If you use the design parameter TRACK 2.0, you will see a term called "dff" in the STAAD output file. This terms stands for the actual length to deflection ratio computed by STAAD. If "dff" is smaller than "DFF", it means the member has violated the safety requirement for deflection, and will be treated as having failed.

26. THIS VERSION DOES NOT DESIGN TAPERED POLE SECTIONS (MEMBER 1). What does this error message mean?

 I am using tapered tubular section properties in my model. When I try to design those members using the AISC code.

The AISC code currently does not have the rules for designing tubular sections which are 6 sided, 8 sided, 12 sided, etc. That is why you cannot currently design them per the AISC code.

There is a code from ASCE called the ASCE publication # 72. That document contains the rules for designing these shapes. Those rules are implemented in STAAD's transmission tower code, and if you have purchased that code, you should be able to design them.

27. I am using STAAD to do steel design per the AISC code. For 2 members with similar cross sections, one passes, the other fails. Fact is, the one which fails has almost no load on it. The other is significantly more stressed but still passes. Is something wrong in the steel design calculations that STAAD is doing?

You will notice that, for the member which failed, the cause of the failure is reported using the phrase "L/R-EXCEEDS". This means that the member has failed the slenderness check.

When STAAD performs steel design on a member per the AISC code, it adopts the following sequence :

It first sets the allowable KL/r in compression to 200 and the allowable KL/r in tension to 300.

For the member being designed, it goes through all the active load cases to see if the member is subjected to axial compression and/or axial tension.

Next, it compares the actual KL/r against the allowable KL/r. If this check results in a FAILure, the member is declared as FAILed, and design for that member is immediately terminated. The requirement to check this condition is in Section B of the AISC specifications.

If the member passes the KL/r check, only then does the program go on to do the remainder of the checks such as axial compression + bending, shear, etc.

It must be noted that failure to satisfy the KL/r check is a reflection of the slenderness of the member, not the capacity of the section to carry the loads which act on it. Even if the axial load or bending moment acting on the member is a negligible quantity, the fact is, failure to satisfy KL/r will result in the member being declared as unsafe as per the code requirement.

If you do not want the KL/r condition to be checked, you can switch off that check using a parameter called MAIN. Set MAIN to 1.0 for a specific member and it won't be checked for slenderness. See Table 2.1 of the STAAD.Pro Technical Reference Manual for details.

28. What do the following parameters mean?

NSF 0.85 ALL
BEAM 1.0 ALL
KY 1.2 ALL
RATIO 0.9 ALL
LY 18 ALL
LZ 18 ALL
CHECK CODE ALL

NSF 0.85: This parameter is called Net Section Factor. One of the criteria used in determining the capacity of a section in Axial Tension is fracture of the net section. The capacity is calculated as NSF X Gross Area X Ultimate Tensile Strength of steel in tension

BEAM 1.0: This means the design or code checking of the member will be done by determining the safety of the member at a total of 13 points along the length of the member. Those 13 points are the start, the end, and 11 intermediate points along the length. If this parameter is not set, design will be performed by checking the safety at only those locations governed by the SECTION command.

KY 1.2: The KY value is used to determine the KL/r for the Y axis -
Ky multipled by Ly divided by Ry.

RATIO 0.9: The code requires one to check the safety of a member by verifying several interaction equations for compression, bending, tension, etc. The right hand side of these equations is usually 1.0. The RATIO parameter allows one to set the right hand side to the value of the RATIO parameter, in this case 0.9.

LY 18: The LY value is used in calculating the KL/r for the Y axis -
Ky multipled by Ly divided by Ry.

LZ 18: The LZ value is used in calculating the KL/r for the Z axis -
Kz multipled by Lz divided by Rz.

CHECK CODE ALL : For ALL members, the safety of the section is determined by evaluating the ratio of applied loading to section capacity as per the code requirements.

29. When one does the AISC code check or member selection, what are the calculations the program is performing?

The checks done as per the AISC ASD 9th edition code are :

1. Slenderness - Checks for KL/r limits per Chapter B
2. Local Buckling per Chapter B
3. Axial Compression + Bending per Section H
4. Axial Tension + Bending per Section H
5. Shear per Section F

30. When I run code checking [as per BS5950] of the steel prismatic members which were defined in the User Provided Table, I get the following message in my output file:

CHECK CODE ALL

DESIGN NOT PERFORMED WITH PRISMATIC PROPERTIES
USER-TABLE MAY BE USED TO DESIGN PRISMATIC SECTIONS

The program is not designing the steel members defined as "Prismatic" in the UP Table, whereas all other members defined otherwise as Tee, Channel etc are being designed. Also I couldn't understand the meaning of the last line "User-Table may be used to design prismatic sections".

Since PRISMATIC sections by definition are those whose section shape is not one of the standard shapes like a W, C, Angle, etc., there are no readily available rules in the code to follow. Due to this reason, prismatic shapes are presently not designed per the BS code nor the ACI code.

You may get around this problem by defining the properties using the GENERAL section in a User Provided Table. For a GENERAL section, STAAD provides the means for providing dimensions of the components that are critical from the standpoint of computing allowable stresses, such as flange, web, etc. The allowable stresses for a GENERAL section are computed using the rules of a wide flange shape (I shape). As a result, the allowable stress value will be dependent on attributes such as dimensions of the cross section, length of the member, etc.

31. I am using STAAD to perform steel design on a member per the AISC ASD code. I want the column to be designed based on an unbraced length of 20 ft. I have set the UNT and UNB values to 20 ft, but STAAD appears to consider only a 10 feet length in its KL/r calculations. How do I correct this problem?

The parameters UNT and UNB are for specifying the unsupported length of the compression flange for the purpose of computing allowable stresses in bending compression.

If you want to specify the unbraced length for the purpose of computing allowable stresses in axial compression, use the parameters LY and LZ. See Table 2.1 of the STAAD.Pro Technical Reference Manual for details.

32. How do I get a design parameter, say the RATIO parameter, to be applied only to certain load cases?

You would need to use the "LOAD LIST" command. For example, if you only were interested in the 1st, 3rd and 5th load cases for the RATIO parameter you would need to write:

LOAD LIST 1 3 5
RATIO 0.5

In your input file.

33. I run the analysis of a 3-D bridge truss model and requested a CODE CHECK of the members. The results of this code check do not correspond to my hand calculation results.

The results of this code check show some very strange numbers in as far as code ratio using AISC- H1-1 formulation is concerned. Reference result output for members number 62 to 74 for example. Other ratios do not seem right either.

If you look at the AISC equation H1-1, you will find that there are 2 terms in the denominator, called

(1-fa/Fey)

and

(1-fa/Fez)

If the value of fa equals or exceeds Fey or Fez (Euler stresses), the respective terms become zero or negative, which is not a desirable event. In such a situation, STAAD replaces that negative number with the value 0.0001. The consequence of this is that, that part of the interaction equation becomes magnified by 10000, which will cause the overall value of the left hand side of equation H1-1 to increase significantly.

The above scenario is what occurs in the case of several of the members in the list 62 to 74. If you want to obtain proof of this, you may do the following. Change the value of the TRACK parameter from 1 to 2, and you will get a more detailed design output. That output will include the values of fa, Fey, Fez, etc.

To remedy the problem, you need to use a larger cross section so that "fa" becomes smaller, or use one with a smaller KL/r value so that Fey and/or Fez become larger.

34. What is the LX parameter used for?

The LX is the parameter used in calculating the axial compression capacity for flexural torsional buckling 

35. The KL/r value that STAAD reports for a single angle member does not match my hand calculation. Design is per the AISC ASD 9th edition code.

A single angle is subjected to 2 buckling modes :

1. Column buckling. This is determined using the simple expressions (Ky.Ly/ry) and (Kz.Lz/rz), where ry and rz are the radii of gyration about the principal axes.
2. Flexural torsional buckling : This mode of buckling uses an equivalent KL/r, which is computed on the basis of equation (4-4) on page 5-311 of the AISC ASD 9th edition code. Generally, this mode of failure produces a higher KL/r than the ones from the column buckling mode.

You should check whether the flexural torsional buckling mode governs in your case. The KL/r calculated for the flexural torsional mode, if it happens to the largest of the 3 values, is reported only with a TRACK 1.0 detail of output. It does not get reported for TRACK 0 or TRACK 2 level of detail of output. In other words, if you want to see the KL/r in the flexural torsional buckling mode, use the parameter TRACK 1.0.

36. What are the SSY and SSZ parameters for AISC ASD based steel design?

SSY and SSZ are terms which dictate how sidesway criteria should be used in computing the Cm coefficients. For both of them, a value of 0.0 means sidesway is present for the corresponding axis, and, a value of 1.0 means sidesway is not present for the corresponding axis.

When SSY is set to 0.0, Cmy is set to 0.85 as per page 5-55 of AISC ASD.

When SSZ is set to 0.0, Cmz is set to 0.85 as per page 5-55 of AISC ASD.

When SSY is set to 1.0, Cmy is calculated as per the equations on page 5-55 of AISC ASD.

When SSZ is set to 1.0, Cmz is calculated as per the equations on page 5-55 of AISC ASD.

If the CMY parameter is specified (and the value is a valid one), that value is used, regardless of what the value of SSY is.

If the CMZ parameter specified (and the value is a valid one), that value is used, regardless of what the value of SSZ is.

37. The KL/ry reported for a T shape does not match my hand calculations. I am designing the section per the AISC ASD 9th edition code. 

For singly symmetric shapes such as Tees and Double Angles, the KL/r value for the Y axis is calculated by STAAD using the rules for flexural torsional buckling as explained in page 3-53 of the AISC ASD manual. It is not calculated as Ky multiplied by Ly divided by ry.

38. Can you provide me with some help on how I can include deflection check as one of the criteria in steel design?

Deflection of a beam or a column can be included as one of the criteria during code checking or member selection with most steel design codes in
STAAD. The ratio of length to maximum deflection of a beam (L/d ratio) will be calculated by STAAD. STAAD will then check that quantity against the allowable limit which the user specifies under the PARAMETERS option.

What are the design parameters which control deflection check ?

1. DFF : This is the value which indicates the allowable limit for L/d ratio. For example, if a user wishes to instruct the program that L/d
cannot be smaller than 900, the DFF value should be specified as 900. The default value for DFF is 0. In other words, if this parameter is not
specified as an input, a deflection check will not be performed.

2. DJ1 and DJ2 : These 2 quantities affect the "L" as well as the "d" in the calculated L/d ratio. They represent node numbers that form the basis for determining L and d.

By default, DJ1 and DJ2 are the start and end nodes of the member for which the design is being performed, and "L" is the length of the member, namely, the distance between DJ1 and DJ2. However, if that member is a component segment of a larger beam, and the user wishes to instruct STAAD that the end nodes of the larger beam are to be used in the evaluation of L/d, then
he/she may input DJ1 and DJ2 as the end nodes of the larger beam. Also, the "d" in L/d is calculated as the maximum local displacement of the member between the points DJ1 and DJ2. The definition of local displacement is available in Section 5.42 of the STAADPro Technical Reference Manual, as well as in Example problem # 13 in the STAADPro Examples Manual.

A pictorial representation of DJ1 and DJ2, as well additional information on these topics is available under the "Notes" section following Table 2.1 in Section 2.8 of the STAADPro Technical Reference Manual.

What are the results one gets from STAAD for the deflection check?

If the steel design parameter called TRACK is set to 2.0, the L/d ratio calculated for the member can be obtained in the STAAD output file. The value is reported against the term "dff". Notice that the expression is in lower-case letters as opposed to the upper-case "DFF" which stands for the allowable L/d.

If "dff" is smaller than "DFF", that means that the displacements exceeds the allowable limit, and that leads to the unity check exceeding 1.0. This is usually a cause for failure, unless the RATIO parameter is set to a value higher than 1.0. If "DFF" divided by "dff" exceeds the value of the parameter RATIO, the member is assumed to have failed the deflection check.

What are the limitations of this check?

Since the "d" in L/d is the local deflection, this approach is not applicable in the case of a member which deflects like a cantilever beam.
That is because, the maximum deflection in a cantilever beam is the absolute quantity at the free end, rather than the local deflection. Check whether STAAD offers a parameter called CAN for the code that you are designing to. If it is available, set CAN to 1 for a cantilever style deflection check.

Since the deflection which is checked is a span deflection and not a node displacement, the check is also not useful if the user wishes to limit story drift on a structure.

39. In the output for steel design, what does the term "dff" represent?

"dff" is the value of actual length divided by local deflection. The actual length value is the distance between the nodes DJ1 and DJ2 which default to the actual end nodes of the member. The deflection used is the maximum local deflection between the points DJ1 and DJ2. You can get the Max. Local Displacement value by looking at the output of the PRINT SECTION DISPLACEMENT command. The definition of DFF, DJ1 and DJ2 may be found in Table 2.1 of the Technical Reference Manual for STAAD/Pro.The word PRISMATIC is meant to indicate a section of any arbitrary shape. But the AISC code does not provide guidelines for design of arbitrary shapes.
Section capacities are dependent upon aspects such as the width to thickness ratio of flanges and webs, lateral torsional buckling etc. From that standpoint, using an allowable stress of 0.6Fy for PRISMATIC sections was not always conservative. 

40. In STAAD-III, I was able to get a steel design for members defined using the PRISMATIC property attribute per the AISC ASD code. I cannot do this in STAAD/Pro. Why?

In the earlier versions of STAAD, the code check for prismatic sections was done using allowable stresses which are arbitrarily chosen as 0.6 Fy. However, this assumption of 0.6Fy was not based on any code specific requirements.

The word PRISMATIC is meant to indicate a section of any arbitrary shape. But the AISC code does not provide guidelines for design of arbitrary shapes. Section capacities are dependent upon aspects such as the width to thickness ratio of flanges and webs, lateral torsional buckling etc. From that standpoint, using an allowable stress of 0.6Fy for PRISMATIC sections was not always conservative.

A way around this limitation (lack of specific guidelines) would have been to use the rules of a known shape, such as a Wide Flange, for designing prismatic shapes. That would require knowledge of equivalent flange and web dimensions. When the properties are defined using the PRISMATIC option, there is no means to convey information such as dimensions of flanges or webs to the STAAD design facility. Hence, the design of PRISMATIC shapes is not supported in STAAD/Pro.

You may get around this problem by defining the properties using the GENERAL section in a User Provided Table. For a GENERAL section, STAAD provides the means for providing dimensions of the components that are critical from the standpoint of computing allowable stresses. The allowable stresses for a GENERAL section are computed using the rules of a wide flange shape (I shape). As a result, the allowable stress value will be dependent on attributes such as dimensions of the cross section, length of the member, etc.

41. In the context of design, what is meant by the term Ratio?

In steel design, the Pass/Fail status of a member is determined according to various conditions. According to most design codes, the member has to be checked for failure against axial compression and axial tension, slenderness, compressive & tensile stresses caused by axial compressive force + bending moments, failure caused by shear stresses, etc. For each of these conditions, determination of whether the member is safe or unsafe is done by checking whether the actual values due to the loading exceed or are less than the allowable values. The amount by which the member is stressed for each of these conditions is quantified in the form of the Ratio. For example, take the case of equation H1-1 of Section H of the AISC-89 specifications. The number obtained by computing the left hand side of that equation is the Ratio corresponding to that equation.

42. I have multiple sets of design in the same STAAD file and I am only able to see the results for the final set in the Postprocessing mode (GUI). How can I view the results for all design sets in the GUI ?

The postprocessing Beam >Unity Check page can report the design results only for the final set of design. This is a limitation in STAAD.Pro as the program architecture does not allow that results of multiple design sets to be made available at the same time graphically. The analysis output file is the only place where you can view results for all design sets. The only way to view the results of a previous design cycle graphically is 

1. to go to the editor and comment out the subsequent design sets and rerun the analysis
2. reverse the order for the design data blocks so that the set, for which the GUI data is needed, becomes the last set.     

43. How is the shear stress calculated in STAAD.Pro for AISC design code ? 

The shear stress calculated by STAAD is the maximum shear stress by default which is based on the standard formula VQ/Ib, where

V = Shear force

Q = Moment of area of the part of the cross section that
is above ( or below ) the plane where shear stress is being calculated, about
the neutral axis

I = Moment of Inertia

b= Width of the section at the plane where the stress is
being calculated

So the term Ib/Q is reported as the shear area that corresponds to this shear stress calculation.

If required one can get STAAD to calculate the average shear stress instead of the maximum. There is a SHE design parameter that can be used to influence how STAAD calculates the shear stress. When the parameter is set to 0 ( default ), stress is calculated as mentioned above. However when this parameter is set to 1, average shear stress will be calculated based on the formula V/Ay (or Az ) where Ay or Az are the shear area for the cross section.  

44. Do you have a plan that STAAD.Pro implements AISI 2007 edition?

AISI 2007 code is being developed, but as part of the STAAD(X) project rather than STAAD.Pro. It should be released in mid next year (2014).

45. A structure that I'm working on I have a 11.6m beam which supports transverse beams and bracing. How can I determine the overall deflection of the 11.6 m beam and check if it is complying with the L/500 criteria?

There are a couple of ways to handle this. One is during the design phase and another is during the analysis phase.

Check during design phase

To ensure that beams are checked appropriately for deflection, using the physical member length as opposed to the length of the analytical segments, please refer to the Note 2 under section 2.4.1.2 ( Design Parameters) from the Technical Reference Manual ( can be accessed through Help > Contents > Technical Reference ) which explains how the design parameters like DJ1, DJ2 and DFF can be used to check deflection for the physical member. In your case, you would specify DFF as 500 for the beam to be checked against an allowable deflection limit of L/500.

Checking during analysis phase

If you are not planning to go for design and would just like to check the deflection based on analysis results, you may define the entire beam as a physical member (PMEMBER). After analysis you will then be able to double click on the physical member ( ensure that your selection cursor is the physical member cursor ) and see the local deflection for the entire physical member.   

See Also

Product TechNotes and FAQs

Structural Product TechNotes And FAQs

External Links

Bentley Technical Support KnowledgeBase

Bentley LEARN Server

Comments or Corrections?

Bentley's Technical Support Group requests that you please confine any comments you have on this Wiki entry to this "Comments or Corrections?" section. THANK YOU!

Error or Warning Message

On computers running Windows 8, the following message appears when opening STAAD.Pro even when product licenses are available:

"Trial/Valid license was not found or trial period has expired! Switching to Restricted Mode..."

Explanation

Make sure that you have at least one license for STAAD.Pro and one license of design code are available to be used. You can check this from the License Checkout section in the License Management Tool (Go
to Start -> All Programs -> Bentley Engineering -> STAAD.Pro V8i ->
Select License Tools -> Select XM License Management Tool ).

If enough license is available, and you are still getting the message, then it could be a registry setup issue. STAAD.Pro uses registry entries to store licensing-specific settings. The settings are stored in a location accessible by all users, but only an administrator can modify them. Starting with Windows Vista, a copy of the settings is also maintained in a location that can be modified by a user. If the settings are never written to the location accessible by all users, the program may encounter a licensing error.

How to Avoid

Option 1: Run STAAD.Pro as an administrator one time.

1. Right-click on the desktop shortcut for STAAD.Pro, and select Run as Administrator. The program should open without licensing errors.
2. Activate any design codes/modules.
3. Close STAAD.Pro
4. Open it as a normal user. It should open without licensing errors now.

Option 2: Explicitly run the STAAD.Pro installer as an administrator.

1. Uninstall STAAD.Pro from the Programs and Features control panel if present.
2. After running the InstallShield extractor, navigate to C:\BentleyDownloads, and open a folder beginning with stpst followed by a version number. For example, the installer for STAAD.Pro 20.07.09.31 is located in a folder named stpst20070931en.
3. Right-click on the executable stored in this folder, and select Run as Administrator from the contextual menu.
4. The installer will reinstall the program and write the missing registry entries.

Note:

Steps in Option 1 can also be used for STAAD.foundation if the message "SELECT license type is not configured yet. Please run “SELECT license Assistance” to configure it" is reported while opening it.

Also the same steps in Option 1 can be used for SectionWizard if it is starting in Demo mode while opening it as a standalone program.

Make sure that you have at least one license for STAAD.Pro and one license of design code available to be used. You can check this from the License Checkout section in the License Management Tool (Go
to Start -> All Programs -> Bentley Engineering -> STAAD.Pro V8i ->
Select License Tools -> Select XM License Management Tool ).

See Also

[[SELECTsupport TechNotes and FAQs]]

As of now there are very limited options for formatting reports from within STAAD.Pro. If you are not happy with the formatting, the best option for now would be to export the report to MS Word ( File > Export Report ) and use the formatting options within Word. That way you can make adjustments to column widths as needed.