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Re: Tilt-Up

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Hugh,

Thanks for the links.

I don't see the economy what so ever for anything bigger than 2 stories in Seismic Zone 4. Two stories generally means office use with maybe some warehouse. Office means lots of windows which means lots of wall piers. Lots of wall piers mean lots of steel in a small area. Lots of steel mean thick panels to try to reduce the steel and to actually fit all the bars required. The mass of two floors or more than two floor requires that you use panels no less than 9" thick at the lower levels if you have at least one solid shearwall per (or several long chunks of wall). The bearing of tilt panels can be accommodate with pilasters and thickened ledges. It's the in-plane capacity that is the problem. Steel braced frame is the way to go for 3-8 story buildings and dual systems above that for high seismic regions. Any concrete building taller than two stories should be shearwall , moment frame, or dual.

Collectors are very difficult to get to work in just 1 story buildings that utilize high load wood diaphragms to deliver seismic. Trying to get 175 kips to drag into a 9" thick panel is very tough. 

Walter, have you looked at the option of Reinforced CMU masonry construction. It is very conducive to economy when labor is plentiful.

-Gerard
>>> HBAP(--nospam--at)aol.com 06/08/01 07:43AM >>>
The 5th Edition of The Tilt-Up Design & Construction Manual covers the '97 
UBC. It is now published by the Tilt-Up Concrete Association (TCA) and a 6th 
Edition is planned to debut at TCA's biannual tilt-up design/construction 
symposium in Washington, DC, in September. For more information visit 
www.tilt-up.org and www.tilt-up.com. Three-and four-story buildings are very 
common with full-height tilt-up and panel thickness is little affected since 
floors provide lateral support. You can see illustrations on the above 
referenced Websites.
Hugh Brooks, SE


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