Wall Pressure Zones 'a'

[wallerdf]

I have a building that has a high roof in the SW corner. The overall dimensions are 840' E-W and 1692' N-S. The high roof is 432' E-W and 750' N-S. The high roof starts at the SW corner. The high roof is 72' and the low roof is 38'. Based on the high roof (>60') my 'a' is 10% least horiz dim = .1(840')=84'. So I'm using that for all four main corners of the building. The corners of the high roof that aren't one of the main corners I used the least horiz dim of the high roof and not the overall .1(432')=43.2'. Does it make sense to do that or do I need to be using 84' at the high roof area also.

 

[woodman88]

Which code are you looking at? The ASCE 7-05 state 0.1(least length) or 0.4h whichever is the smallest but not less than 0.04 the least lenght. For a 72' height I would use 72'(0.4)= 30' and not look at the 38' height for a.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[wallerdf]

It's the ASCE-05. 0.4 h is used for buildings less than 60'. Over 60' it's 10% least horiz dim but not less than 3' (Figure 6-17 Note 8).

 

[woodman88]

As you can tell from my previous response I deal mainly with buildings less than 60'. So I would use the 84' for 'a' as the building least dimension is 840'. Unless I could find some documents that state otherwise. Hopefully someone here can point you to this information, if it is available.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.