Dynamic direct shear strength of the assembled interface of precast bridge piers under impact loading

Abstract

The assembled interface between precast bridge segments plays a critical role in maintaining the structural integrity of precast piers. However, shear-slip failure at these interfaces is likely to occur under high-amplitude lateral forces, such as those induced by impact loading. To investigate the dynamic shear strength of assembled interfaces in precast bridge piers, 40 assembled interface specimens were designed and fabricated, considering the variations in interface configuration, material type, shear reinforcement quantity, and axial force levels. Subsequently, direct shear tests were conducted on 16 specimens subjected to drop hammer impact loading and 24 specimens under quasi-static loading. Based on the test results, a finite element model was developed and validated against experimental data to simulate the shear-slip behavior of the specimens under dynamic loading conditions. Furthermore, existing code-formulated interface shear strength models were evaluated using the experimental and numerical results, and an improved analytical model was proposed to predict the dynamic shear strength of assembled interfaces. Finally, using the proposed interface shear strength model, the failure modes of precast bridge piers under lateral impact loading were analyzed in comparison with their diagonal section shear resistance. The results demonstrate that chemical adhesion, shear keys, axial force levels, and dowel reinforcement significantly enhance the shear capacity of the assembled interface. The proposed analytical model provides accurate predictions of the dynamic shear resistance of assembled interfaces. To prevent interface shear-slip failure in precast bridge piers, it is recommended that the axial load ratio should be no less than 0.025, the longitudinal reinforcement ratio should be at least 0.6 %, and the volumetric ratio of transverse reinforcement should not exceed 1.85 %.