Experimental investigation on the horizontal impact response of precast RC bridge piers with grouted sleeve connections considering defects

To investigate the behaviour of precast bridge piers with grouted sleeve connections under horizontal lowvelocity impact loads, twelve precast reinforced concrete (RC) bridge pier specimens and two cast-in-place reference specimens were tested to study the effect of grouting defect degree, impact velocity and fabricated method (precast vs. cast-in-place) on the impact response of RC piers. The failure modes, rebar strains, impact forces, displacement, and energy dissipation capacity of both cast-in-place and precast specimens were compared and analyzed. The results indicate that due to inertial effects induced by impact loading, the peak impact forces were three to seven times greater than the peak static loads. Transverse cracks were more likely to initiate in the grout layer for precast specimens, with diagonal cracks extending from the loading position to the pier bottom after impact. As horizontal impact velocity increased, the impact force, maximum displacement, and energy absorption ratio also significantly increased. The impact force-time curves of the pier specimens with grouting fullness ranging from 30 % to 100 % showed minimal differences compared to the cast-in-place specimen. A decrease in grouting fullness led to an increase in the maximum displacement of the pier specimens and reduced the transmission of impact waves between the reinforcement bars.