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Message 1 of 15
toha_mh
1816 Views, 14 Replies

Wind Load

Hi, Suppose I need not apply wind loads to a tall building, say 60 meters. Should I calculate all the steps by hand, get the wind pressure and then input the value in WL, or there is any easier way where I can just input the coefficients values and other parameters and it will automatically calculate the wind loads? If I have to do it manually, who should I do it? Thanks
14 REPLIES 14
Message 2 of 15
Artur.Kosakowski
in reply to: toha_mh

You need to do this manually. The easiest seem to define panels (outer walls or curtain walls) and apply load to them.

 

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.



Artur Kosakowski
Message 3 of 15
toha_mh
in reply to: Artur.Kosakowski

Hi, I calculated all the pressures manually according to ASCE 7-05. Now I have pressure for Windward, leeward, sidewalls, roofs from all directions (N-S), (E-W). But the problem is how can I enter these values into robot?

 

I defined four cladding on four sides of the building. Then what shoud I do? How many Wind Load cases should I define and how should I add the loads so that it works according to four cases oif ASCI?

 

Message 4 of 15
Artur.Kosakowski
in reply to: toha_mh

I'm not familiar with the US wind code provisions but usually you need to define 4 wind load cases (from left, right, front and back). In each of them you should have positive pressure on one side of the building and negative one on the opposite one. The code should have also the part that describes wind load on the roof.



Artur Kosakowski
Message 5 of 15

Dear Colleagues

 

Even thou I have to use Brazilian codes in my projects, I do use NV code (French code) to generate the loads in my structures. I believe that results are closer to reality than do hand calculations and load them in the structure.

 

My suggestion would be: try to use the French code to the structure and compare with your hand calculations results.

I am sure that they will be very similar and you gain a lot of time to spending them analying your structure.

 

Thanks

 

Gustavo

Message 6 of 15
toha_mh
in reply to: Artur.Kosakowski

Ok. I can do that. But ASCE says there should be 4 cases. Two of the cases are as follows:

 

Case 1: Full design wind pressure acting on the projected area perpendicular to each principal axis of the structure, considered separately along each principal axis.

 

Case 3: Wind loading defined in case 1, but considered to act simultaneously at 75% of the specified value.

 

Now, if I apply case 1 to all the faces and then make combination, it takes the maximum values from all the faces simultaneously in ULS+, which is more than 75% of the specified value that is required in case 3. Does that mean I don't have to define case 3, only case 1 will be enough?

Message 7 of 15
Artur.Kosakowski
in reply to: toha_mh

Again I'm not the expert on the US code but shouldn't you:

 

1. Define 4 separate wind load cases with 100% value: X+, X-, Y+, Y-

2. Define next 4 separate load cases with 75% value: X+Y+, X-Y+, X-Y-,X+Y-

 

Finally you have 8 separate wind load cases to be combined with other loads (only one wind load case in a single combination).

 

 

 



Artur Kosakowski
Message 8 of 15

Dear toah_mh

 

Test with the French Code and, if necessary, change the requested parameters, or define new load cases.

 

Thanks

 

Gustavo

Message 9 of 15
Refaat
in reply to: toha_mh

Hi all colleagues

 

If possible to prepare your model in CBSpro , you can easily and automatically generate your wind loads for all directions using ASCE7-02 by define your suitable parameters then export to ROBOT

 

Note : see the attached capture

.

Thanks

Refaat

Message 10 of 15
Artur.Kosakowski
in reply to: Refaat

You can also create a model in Revit and export it to CBS.

 

Revit2CBS.PNG



Artur Kosakowski
Message 11 of 15

Are the loads transfered from CBS to Robot?

 

Thanks

 

Gustavo

Message 12 of 15

You can export models (with loads) from CBS to Robot or calcalculate them in CBS using Robot or its calculation engine.



Artur Kosakowski
Message 13 of 15
toha_mh
in reply to: Artur.Kosakowski

Thanks to everybody. I defined the wind loads manually on claddings as Artur suggested. But still there are a few problems.

 

1. If there are shear walls in some parts of a face, should I need to draw cladding over the shear walls also or I can stop at the beginning edge of shear wall?

 

2. After I defined all the wind loads, it takes too much time to calculate. Before applying wind load it took 5.5 minutes, but now it takes 20 minutes. And most of this time is consumed in "applying loads" stage. Is it normal, or there is any problem?

 

I mean, upto now I only defined loads for each cases separately. When I combine them, then it will take even more time.

Message 14 of 15

Toah_mh

 

as I said before, I use NV code and it doesn't take to much time to calculate. Just give a try.

 

Thanks

 

Gustavo

Message 15 of 15

Hi, can you please give a short instruction how I can use it? I don't have any idea?

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