Wednesday, October 28, 2009

Re: Bridging for bar joist

My guess is that there is a misunderstanding.  You do not use braces to provide positive anchorage. They stabilize, not anchor.  It's now standard (page 33 of the '03 Vulcraft Catalog) to provide horiz bridging in the bay adjacent to a much stiffer element such as a wall.  What sort of concrete panel is it?  Could it be that the joist manuf thinks the bridging will be used to stabilize them?  Are the panels more of a cladding than a support?

Byron

On Wed, Oct 28, 2009 at 11:50 AM, Kipp Martin <KMartin@carollo.com> wrote:
Ed,
 
I don't do a whole lot of work with steel joists, so keep that in mind.  I've usually seen that X-bracing converted to horizontal bracing in the end bay.  This is to allow the joist to deflect releative to the non-deflecting wall.  I usually allow the use of either X-bracing or horizontal bracing, leaving it up to the joist manufacturer.  But in answer to your question, I don't see how X-bracing does not provide positive anchorage.  I'd ask the joist manufacturer to explain.
 
--Kipp Martin
  Carollo Engineers
  Portland, Oregon
From: Edward Jonson [edjonson@msn.com]
Sent: Wednesday, October 28, 2009 7:43 AM
To: seaint
Subject: Bridging for bar joist

Question about anchorage of bridging.  I have project where X-bracing of end bay of bridging is called out on plans rather than continuing bridging to concrete panels.  Joist manufacture claims this X-bracing does not provide positive anchorage. So the question is does the X-bracing provide positive anchorage?  Any comments much appreciated.
 
Ed Jonson

at