Full-Scale Tests on Double-Tapered Glulam Beams

Analytical and experimental studies were performed on straight-soffited, double-tapered glulam beams. Full-scale tests were conducted under working loads to evaluate the applicabiLity of the finite element method for theoretical analysis. Two Douglas-fir and two Southern pine beams, each with a span of 30 ft (9.1 m), were studied. Each was instrumented for strain and deflection measurements. Experimental flexural and perpendicular to grain tensile stresses were compared with theoretical predictions. Load tests were also conducted to failure. Both Southern pine members failed in tension due to bending, whereas the Douglas-fir members failed in tension perpendicular to grain. The interaction of stresses concept of failure is evaluated in light of the test results observed in this study.