STAAD.Pro Developing The Model [FAQ]

1. Is it possible to quickly find out the total number of nodes & beams in a model ?
2. How do I stop the Auto Save screen from appearing over and over again in Staad.Pro?
3. How can I define a built up section whose cross section shape is not that of any standard rolled section?
4. I am trying to cut a rectangular hole in an arbitrary triangular region in space which has been meshed with plates. Is there a way to orient the construction grid (for the "snap node/plate" feature) to align with three pre-defined nodes (i.e. the corners of the triangle) to simplify removal of the rectangular feature inside? The angle of the triangle is very odd and I am concerned about the nodes defining the rectangle being slightly out of plane if I try to set the construction grid manually based on the coordinates and angle of the triangle.
5. One issue that I have encountered is that if I go into the load function and realize that I have the wrong units specified, I cannot change the units by going back to the geometry menus and selecting the correct units to use. When I enter the loading menus again, the units have not changed. Is there another way to change the units once you enter the loading functions?
6. When using the foundation support, I am required to give the subgrade modulus and supply a direction. I have always used Y as the direction. However, I am interested in knowing what would occur if I choose Y-only. Is there some type of weak spring placed in X & Z directions, is it completely restrained, or is it somewhere in between?
7. The "View - View Selected Objects Only" option requires two clicks to work.Why ?
8. I am using STAAD.Pro 2004 Build 1004.US also known as the second edition. When I try to add plates using the new feature in the Geometry menu called "Create infill plates", I encounter the message "No closed polygon found to fill in with plates, please check beam selection".What am I doing wrong?
9. 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?
10. How do I access online help in STAAD.Pro? The F1 key does not bring up any help screens.
11. 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.
12. How do I merge 2 staad models?
13. I am designing a mat foundation supporting a steel structure. I am applying the column loads as NODAL LOAD. I do not think this is the right approach because I have a base plate that distributes the load over the area of the base plate. How to model this ?
14. Can one create a user defined grid system in STAAD.Pro?
15. I get a warning message during analysis saying *WARNING- APPLIED SELFWEIGHT IS MORE THAN TOTAL WEIGHT OF ALL STRUCTURAL ELEMENTS IN LOAD CASE    113 ALONG Z. What does this mean ?
16. I am modeling a steel building with braced frame (OBF). I want the braces to carry lateral loads only and not the gravity loads. How can I do that ?
17. Ihavetodealwithrelativelybigmodelwithapproximately50000plates.Howeverprocessingisveryslow.Arethereanylimitationsonnumberofplates?

1. Is it possible to quickly find out the total number of nodes & beams in a model ?

Yes. On the left side of the screen, click on the Setup page. On the right side of the screen, click on the button called "More".

Another place to get this from is the button that looks like a question mark. It is called Info. See the figure below.

2. How do I stop the Auto Save screen from appearing over and over again in Staad.Pro?

From the File menu of the main program screen, select "Open Backup Manager".

The dialog box that comes up has a facility to turn off the Autosave feature as seen in the next figure.

3. How can I define a built up section whose cross section shape is not that of any standard rolled section?

You have to specify its properties using the User Table-General section. You can find the details in section 5.19 of the Technical Reference Manual as shown next. Refer to the section titled General

 

4. I am trying to cut a rectangular hole in an arbitrary triangular region in space which has been meshed with plates. Is there a way to orient the construction grid (for the "snap node/plate" feature) to align with three pre-defined nodes (i.e. the corners of the triangle) to simplify removal of the rectangular feature inside? The angle of the triangle is very odd and I am concerned about the nodes defining the rectangle being slightly out of plane if I try to set the construction grid manually based on the coordinates and angle of the triangle.  

Using STAAD's graphical tools, it is quite difficult to insert an opening after the plate has been meshed, unless your plate elements are aligned in a manner that exactly matches the boundary of the opening. The process is far less painful if the hole is specified before the meshing process commences. To do that, please have a look at the solution described later in this section under the topic "Generation of a plate element mesh for an irregular slab with holes/openings"

Alternatively, you may use Parametric Models option as described in section 2.3.6.11 titled Geometry | Create Parametric Models

5. One issue that I have encountered is that if I go into the load function and realize that I have the wrong units specified, I cannot change the units by going back to the geometry menus and selecting the correct units to use. When I enter the loading menus again, the units have not changed. Is there another way to change the units once you enter the loading functions?

From the Edit menu, choose Edit Input Command File. Scroll down till you see commands like

LOAD 1

or

LOAD 2

Prior to the load case which has the units error, add the appropriate unit as shown

UNIT POUND FEET

For example

UNIT KIP FEET
LOAD 1
SELF Y -1.0
MEMBER LOAD
1 TO 25 UNI GY -0.2
UNIT POUND
LOAD 2
JOINT LOAD
33 FX 400
UNIT KNS METER
LOAD 3
MEMBER LOAD
45 UNI GY -3.0

6. When using the foundation support, I am required to give the subgrade modulus and supply a direction. I have always used Y as the direction. However, I am interested in knowing what would occur if I choose Y-only. Is there some type of weak spring placed in X & Z directions, is it completely restrained, or is it somewhere in between?

If X or Y or Z is specified for direction, then,

a) a spring support is generated in that direction
b) the other two translational directions are fully restrained
c) the associated rotational degre of freedom is fully restrained
d) the other 2 rotational degrees of freedom are treated as unrestrained

Example :

plate-list PLATE MAT DIR Y SUBGRADE 0.4

FX is fixed
FY gets a spring
FZ is fixed
MX is free
MY is fixed
MZ is free

If XONLY or YONLY or ZONLY is specified, then, a spring support is generated in that direction. All the remaining 5 degrees of freedom are treated as unrestrained.

Example :

plate-list PLATE MAT DIR YONLY SUBGRADE 0.4

FX is free
FY gets a spring
FZ is free
MX is free
MY is free
MZ is free

7. The "View - View Selected Objects Only" option requires two clicks to work.Why ? 

This error was present in the American edition of STAAD.Pro 2004 Build 1004. For finding the Release and build number, go to Help - About STAAD.Pro. It has been corrected in Build 1005.US.REL. In case you still need to use the version that had the problem, you could do the following to get around the problem :

a) Go to the View menu and choose "View Selected Objects Only" again.

b) Click the right mouse button, choose "New View" followed by one of the 2 options it offers.

8. I am using STAAD.Pro 2004 Build 1004.US also known as the second edition. When I try to add plates using the new feature in the Geometry menu called "Create infill plates", I encounter the message "No closed polygon found to fill in with plates, please check beam selection".What am I doing wrong?

This was an in build 1004 and has been rectified in the US Build 1005. If you need to use build 1004, you can use the same facility from its icon which is shown below.

9. 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.

10. 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.

11. 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.

12. 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.

13. I am designing a mat foundation supporting a steel structure. I am applying the column loads as NODAL LOAD. I do not think this is the right approach because I have a base plate that distributes the load over the area of the base plate. How to model this ?

There are a couple of things you can do.

1.Instead of applying the load as a concentrated point load, try applying the load as a pressure loading on the plates.

OR

2.You may define dummy members ( having high E and zero density ) between the point of application of the concentrated load and the neighboring plate nodes which would help in distributing the load over a wider area.

14. Can one create a user defined grid system in STAAD.Pro?

Yes, a user defined grid system can be created. You need to go to Geometry menu and select Snap/Grid Node -> Beam. Snap Node/Beam window will appear:

Click on the Create button and this window will appear:

You will need to provide a Grid name, select Grid type (Linear, Radial or Irregular) and set various other options. Once this is done, click OK and created Grid name will appear in the list. Check the box near it to activate that Grid.

As new grids are added or modified, the information is stored in the STAAD.Pro data folder with a GRD extension that allows other STAAD files to re-use these defined grids.

You can also import Grids from the DXF file or Grids previously defined in another STAAD.Pro model by clicking on the Import button. The latter import option opens a browse dialog box to identify a GRD file created by the Snap Node Grid tool. Note that GRD files are only created by STAAD.Pro 2007 (or later).

More information can be found in the STAAD.Pro Help (go to Help -> Contents) chapter AD.2007-1001.1.2 Enhanced Grid Tool.

15. I get a warning message during analysis saying *WARNING- APPLIED SELFWEIGHT IS MORE THAN TOTAL WEIGHT OF ALL STRUCTURAL ELEMENTS IN LOAD CASE    113 ALONG Z. What does this mean ?

First a bit of a background as to why this message was introduced and then the reason for the message. STAAD now support a LIST assignment for selfweight command which it did not in earlier versions. After this was introduced, it was found that many times selfweight was not being assigned to all members by users or sometimes selfweight for few members were being accounted for multiple times due to erroneous assignment on part of the user. A check was therefore introduced in STAAD to warn the user of such scenarios. So what the software does is,

a. It finds out the total selfweight ( UNFACTORED ) of the structure ( say X )
b. It finds out all instances of selfweight command used in each case and checks the associated LIST of members and adds these weights up for each member to arrive at a value of selfweight (UNFACTORED) for each case ( say Y ). While doing this, it ignores any factor applied to the selfweight.

For example, let us consider the following example load cases

LOAD 1
SELFWEIGHT Y -1
…

LOAD 6
SELFWEIGHT Z -2.015
…

LOAD 10
SELFWEIGHT Z -1
…

LOAD 113
REPEAT LOAD
1 1.603 6 1.5 10 0.003
…

The load case 6 and 10 both has selfweight assigned to all members in Z.

So when it comes to load case 113, the software checks and finds that selfweight command has been applied in Z direction to all members as part of load case 6 ( it ignores the factor 2.015 ) and then the selfweight has been applied in Z direction to all members as part of load case 10. It ignores the 1.5 and 0.003 factors applied to the selfweight as part of the REPEAT LOAD. Hence for load case 113, the total unfactored selfweight is applied twice to all members and so the Y comes out to be more ( twice in this case) than X. Whenever Y does not match X, the software flags these as warnings.

Now it does NOT mean that there is an error in the analysis. It is just that the software is trying to make the user aware of the scenario by providing these warnings. For this case, one may simply ignore these warnings.

16. I am modeling a steel building with braced frame (OBF). I want the braces to carry lateral loads only and not the gravity loads. How can I do that ?

This can be achieved by making the bracing members inactive for the gravity load cases and re-activating them for the lateral load cases. The INACTIVE specification for beam members is available within General > Spec page. You can find more details on inactive specification within section 5.18 of the technical reference manual. There is also an example 4, demonstrating how to use the INACTIVE specification, which can be found within Help > Contents > Application Examples. The corresponding .std file is provided with the software and can be found within the folder X:\SProV8i\STAAD\Examp\US where X represents the drive in which STAAD is installed.

17.Ihavetodealwithrelativelybigmodelwithapproximately50000plates.Howeverprocessingisveryslow.Arethereanylimitationsonnumberofplates?

Thelimitsonthenumberofentities,loadsetcareoutlinedinsection5.2oftheTechnicalReferenceManual.Fromourexperience,itisbestifyoucanrestrictyourmodelto30000nodesand30000beams+plates.Althoughtheoreticallyitispossibletoanalyzemuchbiggermodels(NumberofMembers,PlatesandSolids=225000),howeverfromapracticalstandpoint,itisbettertorestrictthemodeltothesizementionedabovebecauseforlargermodels,displayingloadsorevennavigatingthroughtheprogram'sGUIcanbequiteslowandtedious.Alsopostprocessingcanbeveryslowandsometimessomeofthepostprocessingresultsmayfailtoloadinmemory,ifthedatafilesaretoolarge.Soduetotheselimitations,werecommendkeepingthemodelsizesmallerwheneverpossible.

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!

Couple of comments:

Q. How do I stop the Auto Save screen from appearing over and over again in Staad.Pro?

Proposed "solution" is not an answer to the question. The users want to know how to stop the  Auto Save screen popping-up endlessly, not how to turn off auto safe feature.

Q. How do I merge 2 staad models?

First of all - suggested technique does not work - error message "Multiple entities cannot be copied on the clipboard" appears after Edit/Copy. Second - the question is quite clear - "How do I merge 2 staad models", not "How do I merge geometry". Model is much more that just geometry and includes specifications, loads, load combinations, units, groups, etc.