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Fwd: Re: Calc-out versus reality: modeling & research: for Sam Love et al[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: wai(--nospam--at)euken.com
- Subject: Fwd: Re: Calc-out versus reality: modeling & research: for Sam Love et al
- From: rlewis(--nospam--at)techteam.org (Richard Lewis)
- Date: 07 Aug 1997 12:37:21 GMT
Hi I'm new here and clumsy on the keyboard but an old timer in the SE (& arch) scene. Pls forgive wordiness and typos. My motives are pure. <:> Re wood shear walls: we need full scale reversing dynamic testing run by actual designers. Check w/ UC Forest Prod Lab, Ed Diekmann, Ed Zacher, even me. What follows is personal opinion, but it's based on full scale dynamic tests back in 85 by Ed Z and me (see 85 SEAOC Proceedings, Architecture, ASCE 12th World Congress Proceedings). They were great fun and showed a lot of things. First, our current accepted and anointed practice. This model has been around for 40+ years and nobody's happy w/ it. It's related to aircraft design, semi-monococque, tension field or whatever you want to call it. The plywood is supposed to act in pure shear and the plates and studs and rim joists and so on take the flex couple. It requires you to take sections along the edges of the holes and across the wall (or floor or roof) to get unit shear flow in each panel and then take sections along edges of collectors (=drag struts) and apply unit shears found from the panels. Studs at hole edges may show a net residual tension at the bottom: there's your tie-down force. BUT IT DOESN"T REALLY WORK THAT WAY. How about that? In reality each piece of PW moves as a rigid body, translating and rotating trying to follow the parallelogram of the deflected plates & studs (or joists) with the nails bridging the incompatibility and the edges fouling. If you use nice common (ductile) nails, not grabbers or screws or other kinds of cold-worked connectors, the system is ductile at least until the nails get strain hardened. The significant action is in the energy dissipation of the nails and also the edges rubbing and so on. Ed D has full-scale test evidence that it's the number of nails in flexure that counts. I like that. In any case, don't depend on top or sole plate bending for anything. The plumber has been at it with his chain saw for sure. Good luck to us all. Gary --- Internet Message Header Follows --- Received: from server1.seaoc.org (bqe.com [22.214.171.124]) by host1.texramp.net (8.8.5/8.8.5) with SMTP id OAA29285 for <rlewis(--nospam--at)techteam.org>; Sun, 20 Apr 1997 14:01:36 -0500 (CDT) Received: from emout13.mx.aol.com by server1.seaoc.org (NTList 3.02.13) id ja019041; Sun, 20 Apr 1997 11:59:57 -0700 Received: (from root@localhost) by emout13.mail.aol.com (8.7.6/8.7.3/AOL-2.0.0) id OAA22698 for seaoc(--nospam--at)seaoc.org; Sun, 20 Apr 1997 14:57:12 -0400 (EDT) Date: Sun, 20 Apr 1997 14:57:12 -0400 (EDT) From: RGRAYAIA(--nospam--at)aol.com Message-ID: <970420145711_707718436(--nospam--at)emout13.mail.aol.com> To: seaoc(--nospam--at)seaoc.org Subject: Re: Calc-out versus reality: modeling & research: for Sam Love et al Reply-To: seaoc(--nospam--at)seaoc.org Error-To: seaoc-ad(--nospam--at)seaoc.org X-Loop: seaoc(--nospam--at)seaoc.org X-Info: [SEAOC] Owner: seaoc-ad(--nospam--at)seaoc.org X-POP3-Rcpt: seaoc-ad(--nospam--at)seaoc.org X-Sender: seaoc-ad(--nospam--at)seaoc.org Precedence: list X-ListMember: rlewis(--nospam--at)techteam.org [seaoc(--nospam--at)seaoc.org] __________________________________________________ Richard Lewis, P.E. Missionary TECH Team rlewis(--nospam--at)techteam.org The service mission like-minded Christian organizations may turn to for technical assistance and know-how.
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