If the projected centerlines of the web members and their connections coincide with the centerline of the chords, there is no eccentricity. Thus, they will behave as pinned. This assumes the chords are loaded at the panel points/joints, not continuously, or that they are evenly loaded on either side of the joint.
Also, the further apart you place the chords of the truss (the longer the web members), the more the moment in the connections reduce, even if there are eccentricities. At some point moments become negligible (act as pinned).
There are second order effects when the truss deflects that can cause the connection to deviate from purely pinned. Again less pronounced the longer the web members are.
This justifies using pinned connections for the majority of trusses that will not have large deflections or large, unevenly placed loads.
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Jeffrey Walkley P.E., S.E., M.ASCE
Vice President
Michael J Walkley, PA
Towson MD
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Original Message:
Sent: 08-22-2023 03:49 AM
From: Binol Varghese
Subject: Moment Transfer in Trusses
The trusses are designed theoretically by assuming that joints are pin jointed. But practically the joints in trusses are either welded or bolted. How is it justified??
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Binol Varghese Aff.M.ASCE
Assistant Professor
Muthoot Institute of Technology & Science
Ernakulam
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