Test Evaluation of Beam Design Method

Abstract

A series of six wood T-beams, with elastomeric adhesive bonded flange-to-web connections, were tested to compare the measured behavior with that anticipated by the design. The parameters measured were deflection at midspan, stresses at the extreme fibers and the flange-web interfaces, and glue line shear stress. The design method overestimated deflection by an average of 6%, underestimated maximum extreme fiber stress by an average of 10%, and overestimated maximum glue line shear stress by about 12%, for T-beams with continuous flanges. T-beams with transverse flange gaps (unconnected butt-joints) of varying frequency were tested to observe the effect on performance. One gap at mdspan reduced the composite action by 77%, two gaps reduced it by 81% and three equally spaced gaps reduced it by 89%. Flange gaps produced extremely high shear stresses in the glue lines in the vicinity of the gaps. The study results for T-beams with continuous flanges followed the design theory quite well. The flange gap effects were also consistent with theoretical expectations.