Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: Brace connection at mid-point

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Bill,
No one else responded, so I have to blow the dust off some old references. These are also available on the AISC web site.

I would suggest the following references:

AISC Engineering Journal 1987, 3rd quarter, "Design of Diagonal Dross Bracings Part 1: Theoretical Study"

AISC Engineering Journal 1988, 4th quarter, "Design of Diagonal Dross Bracings Part 2: Experimental Study"

AISC Engineering Journal 1986, 1st quarter, "Effective Length Factor for the Design of X-Bracing Systems"

Basically, the tension brace acts as an out of plane brace for the compression brace. The compression brace buckles in an S shape with the inflection point being the intersection of the X brace. You infer that it appears to be a bad idea, but that is how X braces work. That is what has been used in telecommunications towers also.

For double members, I like to make one of the members continuous from each end.

Regards,
Harold Sprague





From: <William.Sherman(--nospam--at)CH2M.com>
Reply-To: <seaint(--nospam--at)seaint.org>
To: <seaint(--nospam--at)seaint.org>
Subject: Brace connection at mid-point
Date: Thu, 8 Mar 2007 07:26:17 -0700

In using cross-bracing connected at the mid-point and designed for tension-compression loads, must both braces be "continuous" thru the joint? In tension-only bracing it is common to interrupt one member and connect with a gusset plate at the mid-point, but it is not clear if the same details can be used for tension-compression bracing. In looking thru references on the AISC website, I could not find direct discussion of continuity of diagonal braces. I have seen various articles that discuss the use of the tension brace to laterally support the compression brace with respect to "effective length" - but a discontinued brace would "encourage" buckling at the mid-point vs a continuous brace. If true full lateral support is provided at the mid-point perhaps it should not matter, but reducing the buckling capacity of the compression brace and relying solely on the tension brace to prevent buckling at the mid-point seems like a bad idea.

If possible, please provide references that address this situation.

_________________________________________________________________
Mortgage rates as low as 4.625% - Refinance $150,000 loan for $579 a month. Intro*Terms https://www2.nextag.com/goto.jsp?product=100000035&url=%2fst.jsp&tm=y&search=mortgage_text_links_88_h27f6&disc=y&vers=743&s=4056&p=5117


******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* * This email was sent to you via Structural Engineers * Association of Southern California (SEAOSC) server. To * subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
* Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you * send to the list is public domain and may be re-posted * without your permission. Make sure you visit our web * site at: http://www.seaint.org ******* ****** ****** ****** ******* ****** ****** ********