wind load and shear wall question

[Alinalysis]

hello all

few questions about wind load and shear wall:

- does it make sense the wind load leads to deformation o 260 mm for 20 storey 40X20 building ? effective speed ~ 52 m/s, basic speed 24 m/s

- when I added the shear it seems that it reduce the deformation to 240 ~ 230 mm is that true ? what's the point of the shear wall if it cannot reduce the lateral deformation ? 

- the bending moment on shear wall reaches up to 50,000 KNm which leads to the failure of the shear wall, it that amount of moment OK ? 

I created a model in etabs so maybe I done something wrong so I asked an expert help who modified my model and the deformation reduced to ~ 13 mm and moment to ~ 17,000 KNm [this makes sense to be but I just want to make sure].

so which result is making sense? 

[UmarMakhzumi]

7 hours ago, Alinalysis said:

- does it make sense the wind load leads to deformation o 260 mm for 20 storey 40X20 building ? effective speed ~ 52 m/s, basic speed 24 m/s

It depends upon kind of framing. Assuming that floor height is 3m, the total height of the building would be 3m * 20 = 60 m. Based on H/200 limit, the max deflection limit, I get 60,000 mm / 200 = 300 mm, so the deflection probably makes sense although its a big number.

7 hours ago, Alinalysis said:

- when I added the shear it seems that it reduce the deformation to 240 ~ 230 mm is that true ? what's the point of the shear wall if it cannot reduce the lateral deformation ? 

The deflection should reduce drastically after adding shear walls.

7 hours ago, Alinalysis said:

- the bending moment on shear wall reaches up to 50,000 KNm which leads to the failure of the shear wall, it that amount of moment OK ? 

I can't comment on that. You should do a manual check (basic load development) to see what the software is giving you is correct.

7 hours ago, Alinalysis said:

I created a model in etabs so maybe I done something wrong so I asked an expert help who modified my model and the deformation reduced to ~ 13 mm and moment to ~ 17,000 KNm [this makes sense to be but I just want to make sure].

Perhaps you can ask that expert to tell where you were wrong as I don't know what you modeled.

Thanks.

[Alinalysis]

41 minutes ago, UmarMakhzumi said:

It depends upon kind of framing. Assuming that floor height is 3m, the total height of the building would be 3m * 20 = 60 m. Based on H/200 limit, the max deflection limit, I get 60,000 mm / 200 = 300 mm, so the deflection probably makes sense although its a big number.

The deflection should reduce drastically after adding shear walls.

I can't comment on that. You should do a manual check (basic load development) to see what the software is giving you is correct.

Perhaps you can ask that expert to tell where you were wrong as I don't know what you modeled.

Thanks.

Thanks my problem is the shear wall didn't reduce the deflection that much so I assume my modeling is wrong.

So what i understand is the shear wall should reduce the deflection significantly, that means the deflection of 13mm after adding shear wall is making sense

[UmarMakhzumi]

You should get significant reduction but it depends how many shear walls you add and what is the length of each shear wall.

If you just add one shear wall, it might not help, if you add two small shear walls the affect might be small, if you add reasonable sized shear walls, then the reduction would be significant. 

Thanks.

[Alinalysis]

On 4/6/2016 at 11:43 PM, UmarMakhzumi said:

You should get significant reduction but it depends how many shear walls you add and what is the length of each shear wall.

If you just add one shear wall, it might not help, if you add two small shear walls the affect might be small, if you add reasonable sized shear walls, then the reduction would be significant. 

Thanks.

Hi

I made a calculation for approximate bending moment, I have the load acting on average of let's say 200KN , that will be 200/40 = 5KN/m distributed load and the height of building is ~75m , so M = 5*75*75/2 = 14,000KNm far away from the 60,000~50,000 KNm that I'm getting. I'm confused and don't know why I'm getting this amount of moment 

My shear wall is 4X6 m in the center of building

Edited April 8, 2016 by Alinalysis

[UmarMakhzumi]

Wind loads are applied slightly differently. I would advise you to see a text book to see an example.

Thanks.

 

[Alinalysis]

On 4/8/2016 at 0:21 AM, UmarMakhzumi said:

Wind loads are applied slightly differently. I would advise you to see a text book to see an example.

Thanks.

 

Hi

When assigning the shear wall to act as one wall it gives a moment of 60,000 KNm

but when assigning each face of the shear wall (there are 5 faces) the moment will be less than 20,000 KNm for each face

which method is correct, assigning it as one member or multiple members

[Ayesha]

For wind in one direction, you will have wind load on Windward side and Leeward side. After applying, the loads will get added. Like Umar said, see a textbook.