Structural behavior of double-lap joints of steel splice plates bolted/bonded to pultruded hybrid CFRP/GFRP laminates

This paper presents results from experimental and numerical studies on the structural behavior of double-lap joints of steel splice plates bolted/bonded to pultruded hybrid CFRP/GFRP laminates. A total of 45 tensile coupon specimens with double-lap bolted/bonded joints and six large-scale flexural beam specimens with/without butt joints in the mid-span section were conducted. Two types of double-lap joints were investigated including bolted joints and hybrid joints (bonded-and-bolted). The results indicate that the double-lap hybrid joint which combined of stainless steel bolts, adhesive bonding, and V-notched splice plates is an effective method of joining the hybrid FRP laminate. The rough surface of the V-notched splice plates and the adhesive bonding contribute to improve the joint stiffness. Numerical analysis was carried out to predict load–displacement curve of the hybrid joints and the results showed a good correlation with the experiments. A design idea for use in the practical design of joints was proposed.

► Double-lap hybrid joint is an effective method of joining the HFRP laminate.
► V-notched splice plates contribute to improve stiffness of the hybrid joint.
► Bolt-end distance has minor effect on failure strength of the hybrid joint.
► Adhesive carries most of the load before major debonding of the hybrid joint.
► Ultimate strength of the hybrid joint is governed by shear strength of the bolts.