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

RE: Fire repairs to Glulam Beams

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Another consideration is that the outter laminations are usually higher
grade material than the inner laminations.  This is because the inner
laminations do not experience the high tensile and compressive stresses as
the outter layers do.

Regards 
Harry Olive, P.Eng.

> -----Original Message-----
> From:	Roger Turk [SMTP:73527.1356(--nospam--at)compuserve.com]
> Sent:	Saturday, July 01, 2000 2:23 PM
> To:	seaint(--nospam--at)seaint.org
> Subject:	Re: Fire repairs to Glulam Beams
> 
> Steve,
> 
> I assume that you have had the charring removed by a light sand-blasting
> and 
> have measured the reduced cross-section and compared it to the undamaged 
> cross-section.  You might find that the damaged section is not damaged as 
> great as it may appear.
> 
> Charring tends to insulate the underlying wood and prevent it from being 
> damaged.
> 
> Using the AITC lamination requirements, the remaining cross-section may be
> 
> more than adequate to carry the required loading.  I think that the first 
> evaluation that has to be done is loading demand and compare it to the 
> section capacity where the damage has been done.
> 
> Based on the information that you provided, if the damage is *centered* 12
> 
> feet from the support, it is at about the 1/4 point on the span, and, for
> a 
> uniform load, the moment is 75% of the maximum moment.  A 10 percent 
> reduction in section modulus should therefore be adequate.  90 percent of 
> the maximum moment would occur at about 1/6 the span (about 7.5-feet) from
> 
> the center of the span.
> 
> Hope this helps.
> 
> A. Roger Turk, P.E.(Structural)
> Tucson, Arizona
> 
> Steve Helfrich wrote:
> 
> >>Can anyone direct me to information on the pros and cons of various
> repairs 
> that can be done to restore the strength of a fire-damaged glulam beam?
> The 
> beam that I am evaluating has lost about 10 percent of its section modulus
> 
> over a distance of about 12 feet, about 12 feet from the end.  The beam is
> a 
> 6 3/4 by 33, and spans 45 feet between supports.
> 
> I have looked into the possibility of using a carbon/epoxy composite 
> laminate, and aluminum sandwich core that is bonded to the beam.  We are
> also 
> looking at a post-tension system.  Client wants to evaluate bolting steel 
> plates to the GLB, and we are also looking at bolting wood (probably GLB)
> to 
> the existing.
> 
> Any thoughts?
>   
> Thanks for any help you can send.<<
> 
> ******* ****** ******* ******** ******* ******* ******* *** 
> *   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) to the list, send email to 
> *   admin(--nospam--at)seaint.org and in the body of the message type 
> *   "join seaint" (no quotes). To Unsubscribe, send email 
> *   to admin(--nospam--at)seaint.org and in the body of the message 
> *   type "leave seaint" (no quotes). For questions, send 
> *   email 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 
> ******* ****** ****** ****** ******* ****** ****** ********

******* ****** ******* ******** ******* ******* ******* *** 
*   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) to the list, send email to 
*   admin(--nospam--at)seaint.org and in the body of the message type 
*   "join seaint" (no quotes). To Unsubscribe, send email 
*   to admin(--nospam--at)seaint.org and in the body of the message 
*   type "leave seaint" (no quotes). For questions, send 
*   email 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 
******* ****** ****** ****** ******* ****** ****** ********