5 Story Wind Load on Building Surrounded by 3 Story Bldgs 1

[RareBugTX]

I am designing a 25'X100', 5 story residential building,urban area, bearing cmu.brick building with a flexible open wood truss diaphragm. I am trying to apply Method 2 (analytical) of ASCE 7-02 but my building will not have wind pushing on the first three floors since it is surrounded at both, the north and south lot boundary lines. Anybody has been through this reasoning before?. Comments will be appreciated.

 

[OkieDokie]

I do not know how much I can help you on this. I am not an Engineer but do work for one. Sometimes I can argue a point to try to save on cost on construction or make things go much easier in the field. A couple of years ago we did the Engineering of some town homes (4 stories). I tried to argue that there is not as much wind load on the building due to the buildings around this building. I lost the argument over "buildings are torn down every day. Hole city block can burn down or cleared for other projects for all that goes. Can you guarantee that the surrounding buildings will be there in 20, 25 or even 40 years to block the wind?". Well, with that question I know I had lost another one, nothing else needs to be said!

Like I said I am not an Engineer but I do know what we take in to consideration in our office and how I lost an argument over about the same issue. You may be able to find a way to only calculate just the top two floors but I could not. By the way, I do win a argument from time to time.

 

[UcfSE]

Some of the effect of surrounding buildings and terrain is accounted for in the exposure category. You don't know how much the surrounding building will block wind load. Just because a building is near a side does NOT mean that side will not receive wind load. You would have to have a wind tunnel test to see these effects. You would also have to guarantee that none of the surrounding structures will be modified or removed during the life of your structure. Bottom line, apply wind load to the whole building like you are supposed to do.

 

[WillisV]

Agreed with UcfSE, you are NOT allowed to assume shielding per surrounding buildings with the analytical procedure of the code. As he said, what happens when they demo the building next door in a year.

 

[JAE]

WillisV is correct, the code explicity denies you the use of surrounding buildings to shield from wind.

 

[jen4950]

Agreed-

 

[Redfish205]

Me too

 

[RareBugTX]

Probably I didn't convey the idea very well, but here's my reason for the thread. I did want a more realistic, rational wind loading on the building. (in reality I was looking for bigger moments and stresses, i.e. wind blowing hardly on the exposed area) Anyway, no savings in analysis or cost were the goal.

Thanks all