ASCE 7-10 3

[vandede427]

Got the new 2010 in the mail today. That sucker doubled in size from the '05 version.

What's happening here people?

There's a 1961 version of ACI 318 on my company bookshelf that's only 30 pages.

 

[msquared48]

What are you complaining about - you got 10 for the price of 5.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[DaveAtkins]

Let me guess--the wind and seismic sections doubled in size.

When I started my career, the wind load section of the Wisconsin Code was one paragraph: you designed MWFRS for 20 psf for buildings under 50', with the wind load increasing for taller buildings.

How is it that all of those "incorrectly" designed buildings are doing just fine?

DaveAtkins

 

[ToadJones]

I always wondered the same thing with wind loads.
It is getting ridiculous.
I think the Empire State Building was one of the first tall buildings to even incorporate wind loads and even then I think it was just some nominal lateral load.

I just started really getting familiar with what little changed in 2005!!!!!!!

 

[vandede427]

If I wanted 1000 page books on my shelf, I would have become a lawyer.

 

[JedClampett]

The good news is that with the code cycle the way it is, no one will adopt ASCE 7-10 for about five years. So we'll all be five years closer to retirement (or death).

 

[vandede427]

from looking at it for about 5 minutes, I can tell this

1. seismic map for S1 stayed the same
2. seismic map for Ss decreased acceleration values on average of 0.05 for each curve
3. they turned one chapter of wind into 6 chapters. I seriously wonder who will use ASCE's 6 wind chapters when IBC just simplified theirs.

 

[audeuce02]

It looks like ASCE is following New Zeland and Austalia on the wind. Corner, edge, and endzones are nothing to them. They have about 10 different zones on the roof surface for variable wind load.

 

[iv63]

Is there a list of all changes between ‘10 & ‘05?
IV

 

[mijowe]

Are the sets construction dovcuments that you all are creating getting larger as well? Seems like i have 2 to 3 times as many sheets of compared to 10 years ago!

I blame computers

 

[FSS]

Florida is trying to fit in the ASCE 7-10 into the next code cycle, so it would be effective sooner than usual.

 

[KBVT]

I know that they have changed the 3-second gust wind speeds from service length to strength level. Not sure exactly how this works out with the return intervals, but the LRFD load combinations have been changed with the 1.6W term being replaced by 1.0W.

 

[abusementpark]

How is it that all of those "incorrectly" designed buildings are doing just fine?

We have these things called factors of safety which help out a lot.

But the point is well taken here. Any building that is still standing is clearly safe and reliable.

 

[leeStruct]

Quote:
"Any building that is still standing is clearly safe and reliable."

Could I interpret this statement as: "Any collapsed poor design building is safe and reliable before the moment it collapsed"?

 

[vandede427]

well, they've now got 4 different wind maps for the 4 different risk categories which has replaced importance factors.

my firm just printed some shirts that say "if you see us running from your building, you'd better keep up."

 

[PMR06]

Prediction... ASCE will issue an addendum to the 7-10 code:

Under Office Live Loads:

Due to the increased weight of design codes, structural engineering offices shall now be designed for a live load of 100 psf.

 

[ToadJones]

plus....
Due to the increased loads of some employees....
never mind, maybe that's jut here....

 

[JStephen]

It has been pointed out before that "they don't build them like they used to" because all the old stuff that was underdesigned collapsed, and what we're left with is the overdesigned stuff.

 

[sundale]

The wind load provisions are written by academics who view practicing structural engineering as a trade, like plumbing. Our profession is led by the nose by people like this.

Performing an overly complicated code wind analysis that jibes with some multi-year PhD dissertation based on wind tunnel experiments is "putting lipstick on a pig" if we do not know the real wind speed data beyond two significant figures.

 

[JedClampett]

When ASCE 7-98 came out (either the first really stinky wind provisions or the first to be adopted by IBC), I went to a seminar by the late James Delahay on wind loads. I posed the exact question that everyone in this thread is asking, "Why do we need an overly complicated wind code when UBC had one page on wind and everything is working just fine?"
His answer was that even though the earlier codes were adequate, we now know more about corners, eoverhangs, etc. and we need to implement this knowledge. His next statement was that since everyone has access to computers now, more complicated and refined analysis could be performed.
Anyway, that's the mindset of the guys and gals that write codes. Accuracy is more important the ease of use. Get a bigger computer.