Differential Deflection - Parallel beams
Differential Deflection - Parallel beams
(OP)
I was wondering if anybody happens to know the limits (if any) to differential deflection between two or more parallel beams. I have a case where the differential deflection between parallel-adjacent beams is as much as 1/4". The beams have a span of 24 ft. Due to the architecture I can not get the beam closer of deeper.






RE: Differential Deflection - Parallel beams
BA
RE: Differential Deflection - Parallel beams
RE: Differential Deflection - Parallel beams
RE: Differential Deflection - Parallel beams
One common specification for flatness is 1/4" maximum deviation in any ten foot section. A ten foot straightedge is used anywhere on the floor to check whether or not the specification is met. I don't think it is often checked and I suspect that not many floors meet the spec.
With uneven loading, differences of that sort could be expected even if the floor is flat when unloaded.
BA
RE: Differential Deflection - Parallel beams
It rarely gets checked either for floors or walls, but can be quite significant, particularly if covered by rigid materials....tile, stucco, etc.
1/4" in 10 feet is a reasonable tolerance so it would appear that you are ok on that count.
RE: Differential Deflection - Parallel beams
Are all the beam bearings at their exact bearing elevations? The .25" Δ doesn’t sound too bad when you consider potential mill and fab. tolerances in beam depth, and camber, etc. Are they all the same size beam, and loaded the same in terms of deflection? Did they all match before being installed?
RE: Differential Deflection - Parallel beams
Analysis and Design of arbitrary cross sections
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Moment Curvature analysis
http://www.engissol.com/cross-section-analysis-des...
RE: Differential Deflection - Parallel beams