Effect of Adhesive Filling on Tensile Performance of Hybrid Tooth‐Bolt Connections for Pultruded FRP Profiles

ABSTRACT Efficient load transfer remains a key challenge in hybrid tooth–bolt connections for fiber‐reinforced polymer (FRP) profiles. Here we propose a simple strengthening strategy based on adhesive filling of the bolt–hole clearance with a high‐performance epoxy resin. We tested joints with different tooth lengths, tooth depths and bolt preloads, both with and without adhesive filling. Adhesive filling markedly increased the ultimate load and pre‐peak energy absorption, while preserving the shear‐dominated final failure mode. It nevertheless changed the damage sequence. In joints without adhesive filling, the teeth carried most of the early‐stage load. Failure occurred abruptly when tooth‐root interlaminar shear triggered in‐plane shear damage around the outer bolt hole. With adhesive filling, the resin formed a continuous shear‐transfer path between the bolt and the hole wall. This promoted early bolt engagement, improved load redistribution and produced a more progressive response, including direct shear and crack‐then‐shear failure. Finite‐element simulations using zero‐thickness cohesive elements and the Hashin criterion captured the measured load–displacement responses and observed failure modes, thereby clarifying the strengthening mechanism. These findings show that adhesive filling provides a simple and effective route to improving the capacity and reliability of hybrid tooth–bolt connections for FRP profiles.