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 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 midspan 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.