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# RE: Quick Help

• To: <seaint(--nospam--at)seaint.org>
• Subject: RE: Quick Help
• From: Harold Sprague <spraguehope(--nospam--at)hotmail.com>
• Date: Thu, 19 Nov 2009 18:20:12 +0000

1)If not 4000 pounds, how much can this beam lift safely?
What is the span?  Back calculating your bending moment it appears you have a 25 ft span.  Correct me if I am wrong.
Braced (how often) or unbraced?
A W 8x18 is the smallest 8" beam with a 5" flange.  The ASD moment is 26.5 kft and the LRFD moment is 39.9 kft.  (Msub rx)  Lsub r is 13.5 ft.  Using ASD you are OK, if you have a brace at about 13.5 ft max.

The other questions are contingent on the span and bracing answers.

2)What minimum size of beam is needed to lift this safely. Deflection is not an issue.

3)If we use two such beams running parallel to one another and separated by about 3'  for the entire span and link them at 3  intermediate points with cross beams of 3' span each how much can be lifted safely assuming
a) the load is shared by the beams and
b) assuming the load is not shared by the two beams but suspended from the bottom flange of one of two beams only with the other beam and cross beams merely used to offer lateral support to the top flange of the beam that takes the load?

Regards, Harold Sprague

Date: Thu, 19 Nov 2009 08:33:19 -0800
From: gvshwnth(--nospam--at)yahoo.com
Subject: Quick Help
To: seaint(--nospam--at)seaint.org