Effectiveness of composite energy dissipation restrainer on mitigating pounding and unseating failure of highway bridges

Abstract

In earthquake-prone regions, large relative displacement between piers and girders may lead to pounding damage and unseating failure in highway bridges. To mitigate these effects, this study presents a composite energy dissipation restrainer (CEDR) that incorporates a composite energy tube (CET) as a fundamental component (comprising an aluminum honeycomb buffer and an expansion tube). The energy absorption characteristics of the CET are analyzed, and the influence of the aluminum honeycomb is thoroughly discussed. Furthermore, a design procedure and mechanical model for the CEDR, considering rare earthquakes, are developed. Finally, the effectiveness of the proposed design method and the behavior of limiting displacement of the CEDR are demonstrated through nonlinear time history analysis of an implemented project. The results reveal that the aluminum honeycomb buffer exhibits superior energy absorption capability, enhancing buffering efficiency and reducing damage. Compared to common cable-type restrainers (CCR), the CEDR reduces the relative peak displacement of the bridge by 40%, decreases the frequency of reciprocating displacement by 30% on average, and mitigates impacts on the abutment by 80%.