Friday, September 14, 2007

RE: Practical Example of wind design for multi-story residential wood framed analysis needed for 2006 IBC and ASCE 7-05

Dennis:
 
In my opinion the Wind Analysis based on CBC 2007 (ASCE 7-05) for low and mid rise structures are relatively easy but a lot more time consuming than the current CBC 2001.
However based on the information that I've got form Howard Smith & Bill Staelhlin down at the DSA, about two weeks ago, a new simplified Wind Design method will be available by early 2008 for California structural engineers.

Regards

Khashayar (Casey) Hemmatyar, SE
Private e: khemmatyar@hotmail.com

________________________________________
From: Dennis Wish [mailto:dennis.wish@verizon.net]
Sent: Thursday, September 13, 2007 5:42 PM
To: seaint@seaint.org
Subject: Practical Example of wind design for multi-story residential wood framed analysis needed for 2006 IBC and ASCE 7-05

I have a lot of information related to the calculations necessary to be run for compliance to the ASCE 7-05 Simplified wind design. This does not put the problem in a realistic perspective for me when comparing wind to seismic loads and the actual distribution of shear based on flexible diaphragm design. What I am looking for is an example analysis for a two story and one story building to see how wind and seismic loads are compared. I've reviewed the ASCE 7-05 Simplified wind design and it is included in the TEDDS library as well. However, while I can see how the loads are calculated for the uplift on the overhangs, leeward and windward sides and each other load condition, I am lost when trying to work a traditional example in Southern California for the design of a single or multi-story wood frame structure (less than three stories) where seismic design and wind loads can be applied using our traditional flexible design methods. For the first time in history, the seismic design is so much easier to understand than the wind loads but I suppose this makes sense in the coastal regions subject to high wind loads.

The Seismic Design manual published by ICC for the 2006 IBC volume II contains examples but I am hesitant to spend the price for the manual after being disappointed by the 97 UBC first publication of these examples with errors in place. I also received a notice that there will be a 1-1/2 hour web seminar that I can participate in for $250.00 and this is out of the questions for me. I can't possibly justify working out a solution to the wind design section (the only section that I am currently stumped on) for $250.00. The one advantage is that I can invite all of the local engineers into my office and sit around my one 19" monitor to view the webcast and spit the cost to about $40.00 per person, but I doubt if we could all see the largest screen I have and to run it on two connections according to S.K. Ghosh Associates, Inc. latest advertisement would cost an additional $250.00 or some slight adjustment. I am being facetious for a reason since $250.00 for a 90 minute seminar is something I should consider competing in. I can do it for a tenth the price and pick up almost all of the engineering community and would not mind making it a full day seminar for the profit it would return. Do you really think you can leave the seminar after 90 minutes and understand what to do? I don't think it can be done since the last time I attended the S.K. Ghosh seminar in Riverside (an hour or so away) it was a full day and came with a copy of the code. I still did not think it covered enough of the issues, but at least it was about half this price and a full day ICBO seminar.

So let me ask – has anyone started to do some sample problems (realistic designs) for light frame residential design that has a copy of your work you are willing to share with the rest of us. I want to add the wind design into my public domain MultiLat program and am delayed in getting this out to beta testers since the information I have has not reduced the confusion and frustration I am experiencing on the wind load portion.

Finally, as another pointed out, for my practice I will need the 2006 IBC (already have it), ASCE 7-05 (I've have some of the drafts), AF&PA (the most worthwhile publications when considering cost), AITC for Glu-Lam's which I believe the fourth edition is probably sufficient, NDS which may not be necessary if I stick to ASD methods, AISC (not necessary for the little steel work I do) and probably the IBC Existing Building Code because I still do some retrofit of existing buildings. Therefore, my cost is such that I don't see why most of us can avoid seminars and learn from each other off this list. If you have an office with employees, then maybe you can justify the cost of reference and seminars. If you are a one person show, then expect to be forced out of business by the cost of doing business – the competition in outsourcing is currently biting me in the butt as I am attempting to earn a living at the cost of all of the necessary references.

Thankfully, there are proprietary materials who will do some of the work for you (like MiTek's SidePlate moment frame). I heard yesterday that the City of San Diego was already planning on addendums to the IBC or state adopted code when they anticipated no addendums a few months ago. I am interested in seeing what small towns like La Quinta will do to adopt the next California code 

About 9 more years to retirement and then I will have fun spending my days writing software to give away rather than feeling the burnout of having to make a living and seeing my costs rise and profits fall.

Sorry – I am just feeling the stress of all of the latest cr*p to hit the fan..

If you have run some numbers and can share with me the practical application of a light frame single or multi-story seismic verses wind design on a residential structure using flexible diaphragm analysis, I would be greatly appreciative and will even give you a free copy of my already free software – MultiLat once it is finished 

Thanks,
Dennis

PS: If you have it in PDF format or can put in PDF format this would help. If not you can fax it to me at 1.760.564.0884

PPS: For those of you who observe, I wish you all a Happy and Healthy Jewish New Year 5768