Shear failure strength of web–flange junctions in pultruded GRP WF profiles

Ultimate load tests on pultruded GRP WF (wide flange) profile beams and columns have shown that final failure is triggered by separation of one or both flanges from the web. Strengths determined from coupons cut from the web and flanges do not provide accurate predictions of web–flange junction strengths, because of the presence of a roving-rich core at the heart of the junction. Here, details are presented of an investigation to determine the shear strengths of web–flange junctions. The details include: the preparation of the web–flange junction specimens, a description of a new test rig for determining junction shear strengths and the underlying theory on which it is based, and the shear strengths obtained from unnotched and notched web–flange junction tests on two sizes of WF profile. It is shown that the shear strengths of the web–flange junction specimens are much lower than those of flat coupons.