Experimental determination of the pull-out strength of mechanically fastened steel rods into glulam beam sections having different rod lengths and washer sizes

Abstract

A new tension connection configuration utilizing threaded steel rods that are mechanically fastened into glued-laminated timber (glulam) sections has been experimentally investigated in this study. Nine different connection configurations have been examined, with each configuration being replicated four times to verify results. The glulam connection parameters studied were rod embedment length (150, 200, and 250 mm) and washer bearing area (38.1 × 38.1 mm, 50.8 × 50.8 mm, and 63.5 × 63.5 mm). Experimental results show that the largest washer (63.5 × 63.5 mm) induced wood splitting failure in the beam section more frequently as the rod embedment length decreased, creating the largest standard deviation in results among those of the three washer sizes tested in this study. Whereas the smallest washer (38.1 × 38.1 mm) induced wood crushing failure with the greater displacements into the glulam section when the rod embedment length increased. However, the dominant failure mode in the test specimens that employed the medium washer (50.8 × 50.8 mm) was rod pull-out since the washer was not too large to induce wood splitting nor too small to induce wood crushing failure in the glulam section.