Seismic strengthening of RC bridge piers using UHPC jacket and high-strength steel wire mesh: Experimental investigation and numerical simulation

Abstract

To enhance the seismic performance of reinforced concrete (RC) bridge piers (e.g., those with early design limitations, construction defects, or long-term degradation), this study proposes a strengthening method combining Ultra-High Performance Concrete (UHPC) jackets with high-strength steel wire mesh (HSWM) in plastic hinge zones. Quasi-static tests were conducted on five UHPC-HSWM strengthened piers and one control pier to evaluate seismic performance metrics, including failure modes, hysteresis behavior, displacement ductility, energy dissipation, and stiffness degradation. The effects of the HSWM arrangement, thickness and height of the UHPC jacket on the seismic performance of bridge piers were studied. The experimental results show that the combination of HSWM and UHPC not only improves the restraint effect of the UHPC jacket but also fully leverages the fracture toughness of the UHPC material, resulting in fuller hysteresis curves. When the thickness and height of the UHPC jacket were 50 mm and 450 mm, respectively, the displacement ductility coefficient and overall energy dissipation capability of the strengthened specimens were increased by 31 % and 245 %, respectively, compared with the control specimen. The K value in the Concrete02 model was adjusted in the OpenSees to account for the enhancement roles of steel fibers and HSWM in UHPC. A finite element model on seismic performance of RC piers strengthened with HSWM-reinforced UHPC jacket was developed and validated against experimental hysteresis data.