Effect of bolt size on the bearing strength of bolt-connected orthotropic CFRP laminate

Carbon fiber reinforced polymer (CFRP) has the advantages of lightweight, high strength and corrosion resistance. CFRP laminate is widely used in the reinforcement and rehabilitation of concrete and steel structures such as buildings, bridges, and tunnels. In this work, the structural arrangement of six kinds of orthotropic CFRP laminates that would suffer from bearing failure was determined with the help of a failure map. The bearing strength and failure mechanism of the specimens at the joint were studied through tensile bearing tests. Finally, a strength prediction model about the effect of bolt-hole size was established based on the Weibull distribution theory. The research results show that the bearing strength of the CFRP laminates is insignificantly affected by the thickness of the CFRP laminates, however, is greatly affected by the diameter of the bolt under the same thickness and lay-up form. The bearing strength of the CFRP laminates decreases with the increase in the diameter of the bolt hole. It is found that the specimen with a symmetrical layup shows a more obvious size effect compared to the specimen with an asymmetric layup. The model established based on the Weibull distribution theory can well predict the bearing strength of bolted-connected CFRP laminates with different diameters.