When using multiple ply Versa-Lam® beams in lieu of a single section member, the connection of the plies is as critical as determining the beam size. When side loaded beams are not connected properly, the inside plies do not support their share of the load and thus the load carrying capacity of the full member decreases significantly. The following is an example of how to size and connect a multiple ply Versa-Lam® floor beam.
Given: Beam shown below is supporting residential floor loads (40 psf live load, 15 psf dead load) and is spanning 16’-0”. Beam depth is limited to 14”.
Find: A multiple 1 3/4” ply Versa-Lam® that is adequate to support the design loads and the member’s proper connection schedule.
- Calculate the tributary width that the beam is supporting: 14’/2 + 18’/2 = 16’.
- Use PLF tables shown in Versa-Lam® Specifier Guide or enter the loads and the span in BC Calc and run Best Beam for 2, 3 & 4 ply beams: A Triple 1 ¾” x 14” Versa-Lam 2.1E 3100 is found to adequately support the design loads.
- Calculate the maximum FACTORED plf load from one side (the right side in this case) that will be used to select the multiple ply connections.
Max. FACTORED Side Load = (18’/2) x [(40)(1.5) + (15)(1.25)] = 708.75 plf
- Go to the Multiple Member Connection Table in the Versa-Lam® Specifier Guide. Side-Loaded Applications, 1 ¾” x 14” Versa-Lam, 3 plies.
- The proper connection schedule must have a max. FACTORED Uniform Capacity greater than the max. FACTORED side load:
3 rows 16d Common Wire Nails @ 12” o.c.: 976 plf > 708.75 plf OK
- The same procedure is applicable for Concentrated Side Loads (factor the loads; 1.5 Live + 1.25 Dead, and select the proper connections based on the max. factored load).