Numerical analysis of quadruple fastenings with bonded anchors

This paper addresses the failure mechanism and the failure load of quadruple fastenings with bonded anchors. The studied specimens were adhesive anchors anchored in a concrete block and subjected to tensile loading. Numerical analysis was performed using a microplane model with relaxed kinematic constraint to simulate the concrete material, and a special interface model to represent the adhesive material. Two typical experiments with different failure modes were simulated, Calculated load-displacement curves and failure modes agree well with experimental data. Furthermore, an extensive parameter study was performed by varying the embedment depth h(ef) (h(ef) = 4d to 20d), spacing between anchors (s = 0.25h(ef) to 2.5h(ef)), and anchor diameter (d = 8, 12, and 20 mm). These studies reveal the failure mechanism of bonded anchor groups and clarify the group effect on the failure load. Based on the numerical and experimental results, a model for evaluating the failure load of quadruple fastenings with bonded anchors is proposed.