Wind Loads on Steel Structures

It is a matter of concern that, in staad pro, the features available for applying wind load is not fully automatic (unlike other design softwares) , but there is much more lacking in it, which is briefly described as below, There is automatic application of wind load only for few types/shapes of roofs/structures ,like rectangular building,pitched roof, mono slope roofs. For many other types of roofs, like saw toothed roof,cantilever roof,multispan pitched roof, combined roof, inverted pitched roof, inverted mono slope roofs, cylindrical shaped structures etc, the automation of wind load is not available, (or available partly). Moreover, automatic wind load for all types and shapes of "ROOF PURLINS", "COMMUNICATION TOWERS", wind load on circular or elliptical shaped column is not available in staad, local wind coefficient (for corner pressures) is not available, automatic calculated solidity ratio/ shielding factor is not available. It is very demanding that wind load in staad should be available for all types of roofs and purlins with Full automation and can be applied with few clicks, For illustration, refer "TABLE NO. 04 to 24" of IS 875 part -3", refer following PDFs 1st PDFs: wind load on frames 2 nd PDFs: wind load on roof purlins. In short, wind load in staad should be available for all types/shapes of of roof/building, purlins and not only for global X and Z directions ,but it should also available for 45⁰,135⁰,225⁰,315⁰,270⁰ etc.

We should simply be able to choose the wind spec, API, ASCE, or whatever other codes may apply. We should not have to go through three steps to apply it as we are doing now. In SAP2000, it is a one step application. In STAAD, it is at least three steps to apply create the wind load, and others to apply it to the appropriate structural members. For items that are any type of frame structure, this is too much work for the wind load application.

To make sure we properly understand your idea, please can you clarify how you want the procedure to go?

1) Is to chose a code which will have multiple requirements that you will need to check and verify are appropriate to your specific situation.

2) define where the will come from relative to your model and you want to program to work out what parts of the model are enclosed.

3) Are you saying that you would like this one action to also create the effects on wind panels on the sides and rear of the building (as is done with the Wind Load Generator to the IS 875 code).

So is this the issue, you would like the same for a different code such as the ASCE code?

SAP 2000 provides multiple ways to define wind loading. Your request will only make sense if you provide some detail and perhaps I would have thought you might even say what could be done to make it be even better!

We should not have to do nearly as much work to get the correct wind load in the model. It should be a simpler procedure, example being SAP2000, SACS, or other programs where we generally just place the velocity and let the program take care of other variables, generally speaking. Especially for API wind loads.

There are many good solutions provided by many solution providers. Our goal however is not to copy anyone, but to provide an offering that solves the problems that the engineer is facing. Can you describe the best way you think the wind could be assigned. Try and think about generic models and requirements that may be levied from other design codes so that your method would solve the needs for other engineers who might be working to other specifications. Providing a better offering that delivers that should be our goal here.

No. I'm recommending you look at other programs like SAP2000 and see how simple the wind load input is. In other words, your wind load input takes four times the amount of effort of other programs. It's time to being STAAD to the 21st century in terms of wind load input.

TI am sure that you have seen that we recently added a routine for creating wind loading to the Indian IS 875 (part 3). This can create the wind loading on clad/unclad structures both creating the definition and load cases with the necessary reference. Are you suggesting something similar for the ASCE wind loads?

I understand your reply. However, that is not the point I am trying to make.

The user should be able to simply pick the wind spec, ASCE 7, or ABS or whatever it may be, then simply input the velocity and other items. In STAAD it takes 3 times as long as other programs, as we have to build this data up from the "Wind Definitions" rather than simply pick this from a menu as in other programs like SACS or SAP2000. SAP2000 is much more user friendly to input wind loads, as well as most other loads. Since it takes less time, it allows me to do more work.

STAAD already has this option. The default is that the program will treat the model as an enclosed structure. However, you should see that there is an option in the dialog when the wind load definition is applied in a load case, that it can be set to 'Open Structure',. In other words, the frame is not enclosed and the wind loads applied purely to the surface of the frame members.

Glad to hear others agree. STAAD seems to be purely basing the wind load upon ASCE or something equivalent. What I am looking is a simple way to apply wind to an open frame structure, similar to another product you make, called SACS.

Thank you for posting this idea. As you can imagine our goal is not to copy other solutions, but will look at ideas that that deliver value and improved productivity where we can. The challenge is determining a tributary areas on a general model that may or may not be a building frame. We are providing a tool that can define a zone which encompasses internal members and openings as a tool for creating floor loads. This can be extended to define lateral loads too, although would need more work to account for variable pressures too. Is the spreadsheet something that you would be able to share?

I agree, and very limited as well.

I prepared a spreasheet for mexican code that considers the coordinates of the nodes and members, calculates the wind profile variation due to height, the tributary area between coordinates of columns, the reduction of pressure due to area, the change of pressure depending on distance from windward wall, if a column is between two pressure zones, it calculates the tributary area of each zone for the column and such. In terms of programming... is the most basic stuff, not even VB, simple tables and formulas. I'm sure the development team can make it much better, and without weird rules such as "close panels"