ASCE 7-10
ASCE 7-10
(OP)
anyone know the release date for ASCE 7-10?
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
|
RE: ASCE 7-10
I recently reviewed a draft copy of the code and there are some significant changes in ASCE 7-10.
RE: ASCE 7-10
Ryan Coggins, P.E., S.I.
http://www.linkedin.com/in/ryancoggins
RE: ASCE 7-10
RE: ASCE 7-10
http://content.seinstitute.org/publications/
Also the newest nehrp is out.
htt
RE: ASCE 7-10
RE: ASCE 7-10
RE: ASCE 7-10
Almost half of it is seismic - we are now officially entering the realm of "Let's see how precisely we can calculate an estimate of loads and forces." Do these folks not realize that they are requiring very precise calculations based on the estimated forces of an unknown event?
As I say in my presentations: You don't get a better building by using a sharper pencil.
RE: ASCE 7-10
After sitting 7-05 and 7-10 side-by-side and going through a wind pressure calc on a simple mono-slope roof, I'm getting pressures that are about 19% more for the new code.
What gives?
We're talking billions more in construction costs to design for these wind loads. Plus, for those of us that do lots of work on existing structures, we'll need to go back and strengthen them...
If you "heard" it on the internet, it's guilty until proven innocent. - DCS
http://www.eng-tips.com/supportus.cfm
RE: ASCE 7-10
RE: ASCE 7-10
YOu are correct. I did a quick comparison for upper midwest area:
ASCE 7-05 ASCE 7-10
Occ. cat III Risk Cat III
I = 1.15 I = N/A = 1.00
speed = 90 mph speed = 120 mph
Kd = 0.85 Kd = 0.85
Kzt = 1.00 Kzt = 1.00
Exp C Exp C
H = 33 ft H = 33 ft
Kz = 1.002 Kz = 1.002
qz = .00256KzKztKd*V2*I qz = .00256KzKztKd*V2
qz = 20.313 psf qz = 31.402 psf
LF(ASD) = 1.0 LF(ASD) = 0.6
qz*LF(ASD)= 20.13 psf qz*LF(ASD)= 18.84 psf
LF(LRFD) = 1.6 LF(LRFD) = 1.0
qz*LF(LRFD) = 32.50 psf qz*LF(LRFD) = 31.402 psf
I think if there are areas where the change in speed is different (for example, on the fringes of the old 90mph contour where the new speed is not 120) then for those locations the new code might be more or less than the old code. In the areas near the coast, I can't say how the contours have changed. Note that for different Occ Cat/Risk Cat, this analysis will look different because I is different, and new speed on the new map will also be different.
regards,
chichudk
RE: ASCE 7-10
So now they confuse things even more by changing the wind loads calculated to ultimate load versus working load. The industry, particularly air conditioning equipment manufacturers, hasn't even caught up with the '05 requirements yet. Almost every day, I have issues with our mechanical guys saying they can't find rooftop units that meet the new rooftop equipment pressures in ASCE7-05. Now they'll really be confused by ultimate pressure versus 'we tested it at 150 mph...." Fortunately, it will be several years before it comes into effect, at least here in Florida.
RE: ASCE 7-10
I understand why they did it, but it would have been nice if they would have just moved all of the loadings over to ultimate at once instead of doing one section at a time per 5 year revision. Maybe it was too much of a workload to do it all at once...
If you "heard" it on the internet, it's guilty until proven innocent. - DCS
http://www.eng-tips.com/supportus.cfm