Quasi-plastic flexural behavior of adhesive-bolt hybrid connection for large scale pultruded GFRP frame

Flexural behavior of an adhesive-bolt hybrid connection for pultruded glass fiber reinforced polymer (GFRP) frame is investigated through monotonic and cyclic loading tests. It is shown that the hybrid connection fabricated using resin adhesive and steel bolts is able to exhibit a quasi-plastic behavior. Multistage damage occurred in tests, and the adhesive failed initially, followed by GFRP failure at bolt holes. Effect of shear force was investigated by variable shear-span ratios in tests. Additionally, moment and rotation curves obtained from monotonic and cyclic loading tests are found to be similar, indicating that loading schemes have little impact on structural performance of the hybrid connection. Energy dissipation is analyzed based on cyclic loading tests. Finite element model is also built, and design formulas are proposed to predict the quasi-yield moment and maximum moment. A good agreement is found between experimental results and analytical predictions. In addition, design recommendation on the use of adhesive-bolt hybrid connection is provided.