picnic shelter

[v2]

Consider an open structure (picnic shelter)
Should the roof be considered as an overhang for calculating the wind load pressure by the ASCE7-98 procedure?

or what is the true definition of an "overhang" in ASCE7-98?

Thanks.


V2

 

[JAE]

We just faced that decision on a swimming pool bathhouse where a portion of the bathhouse had a large roof overhang - we opted to go with the overhang uplift pressure - We just felt that we could visualize a high wind sending the 15 feet of roof sky high.

 

[Ron]

v2...I look at those in two different ways. In one, I use the approach JAE mentioned. Another, if the roof is flat, I use the "open structure, monoslope roof" approach. The second approach does not consider overhang. It's a judgment call, and it doesn't hurt to be conservative! If the shelter is contiguous with another structure, use the overhang approach whether flat or not.

 

[JAE]

Yes, I'd agree with Ron - our project was a complete building with a portion (about 15' x 70') that was really an overhang even though it was a simple extension of the roof.

For a completely open building - some kind of monoslope system would be appropriate - the primary failure is really a straight-upward suction.

 

[JAE]

By the way, Ron - working late on a Sunday?

 

[Ron]

JAE..if I stay away from it too long, I have to be retrained!

 

[Ron]

Also, JAE...you're post was obviously after mine, so that would probably put you in my same boat! Be afraid...be very afraid!

 

[v2]

People, thanks.

Just to let you know, the shelter is on its own structure not associated with any other building. and the shelter has a 5/12 hip roof slope.

oh by the way, I can visualize it flying too.



V2

 

[JAE]

Ron, so what you're saying is that engineering is nothing like riding a bicycle. Once your off....you cannot get back on!?

re: Sunday night - I was here but not working (getting my son familiarized with Autocadd for a summer job).

 

[Ron]

JAE..you bet!

Keep in mind there are probably laws against exposing young minds to this screwy profession, although if he's like his Dad, we can use all we can get!

 

[JAE]

Well...gulp.....he's going into Architecture.

I think he'll be a good one as he's already slamming engineers!