InTrans / Aug 14, 2018

Experimental shear strength of glued-laminated beams

The allowable stress in shear is derived from shear tests of small clear shear blocks, but the shear strength of shear blocks is much greater than the shear strength of larger beams. In this study, glued laminated beams were tested to determine shear
strength. These specimens were tested in the five point bending test configuration. Shear blocks were cut from the beam after failure and tested for shear strength. From these tests, a relationship between shear strength and beam size was developed that uses American Society for Testing and Materials (ASTM) shear block strength as a basis. The recommended relationship is based on test results for a number of sizes of Douglas-fir and southern pine unchecked
glued-laminated beams. This recommendation also includes the stress concentration factor to account for the effects of the re-entrant comer in the ASTM shear block specimen.