Monday, October 31, 2011

Standard Portal Frame Analysis

I’m doing stuff I should done in school J


1)      I am reviewing how to quickly arrive at sway in a rectangular (or any, for that matter) portal using simple portal frame equations.

2)      I calculate the moments from the std equations and then release the top corners to arrive at a flagpole concept tied at tops by a strut/beam.

3)      The resulting base moments are approx by iterative moment distribution.

4)      If I use a partial, or offset, load on the beam I expect sway.

5)      My question is, “Is it too simplistic to take the resulting moment difference at the bases and apply slope-deflection arithmetic to arrive at an estimate of the sway?”




Thor A. Tandy P.Eng, C.Eng, Struct.Eng, MIStructE
Victoria, BC, V8T 1Z1

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