Junrui Zhang - 2025 NZSEE Annual Technical Conference - Experimental Investigation and Analytical Modelling for Interfacial Behaviour of in End Fibre Anchored EB-FRP Systems Strengthening on RC Structures

Externally bonded fiber-reinforced polymer (EBFRP) systems are widely used to strengthen reinforced concrete (RC) structures, yet premature debonding limits their effectiveness. End-anchorage techniques enhance load transfer efficiency and mitigate interfacial bond failure by providing additional resistance against slip propagation. This study investigates the load-slip response and anchorage performance of single end-anchored EBFRP systems through experimental testing and analytical modeling. Twelve large-scale single-lap shear tests (1370 mm × 460 × 150 mm) were conducted to evaluate the effects of anchor dowel diameter, fan length, and concrete compressive strength on load transfer efficiency. Experimental results capture the transition from interfacial shear stress transfer to anchorage engagement, demonstrating how bond length influences stress redistribution and the progressive role of the anchored region in resisting slip and delaying debonding failure. An analytical model was developed to characterize load-slip behavior, incorporating a bond-slip constitutive relationship for the bonded region and a bilinear elastic-hardening framework for the end-anchored region. The model explicitly accounts for anchor deformation, force redistribution, and anchorage-dependent failure mechanisms. Strong agreement between analytical predictions and experimental results validates its capability for predicting anchorage engagement and load transfer mechanics. By integrating Mode II fracture-dominated load transfer with anchorage resistance, these findings contribute to the optimization of anchorage design strategies, improving the stability, durability, and efficiency of EBFRP strengthening applications in RC structures.