Seismic strengthening of RC bridge piers with high-performance cementitious jacketing: A comprehensive review, recommendations and a precast HPC-FRP grid jacket proposal

Abstract

This paper reviews high-performance cementitious jacketing for reinforced-concrete (RC) bridge piers under seismic loads. Specifically, the review (i) combines experimental and numerical evidence from monotonic, cyclic, and shaking-table studies; (ii) discusses the key mechanisms such as confinement, crack control, and shear transfer at the interface; and (iii) offers practical advice on jacket height and thickness, splice and plastichinge details, and construction in tight spaces. The literature shows that high-performance concrete (HPC) systems, which include ultra-high-performance concrete and ultra-high-performance fiber-reinforced concrete (UHPC/UHPFRC), generally boost lateral strength, drift capacity, and energy dissipation. Thin jackets can also enhance crack control and durability, which helps limit section enlargement, added weight, and foundation demand. They can also support staged construction while traffic remains active. Several key issues persist, including the reliability of jacket-core bonding, field placement and curing, multi-hazard durability (like chlorides, fatigue, and thermal/fire exposure), and the balance between cost and sustainability. To tackle these challenges, the paper highlights hybrid concepts where HPC/UHPC shells use FRP grids to combine compressive and shear strength with tensile crack-bridging and protection from the environment. Expanding on this idea, a precast HPC permanent-formwork jacket with embedded FRP grids and pressure-grouted infill is proposed. This aims to improve the quality of the interface while reducing thickness and shortening closure time compared to cast-in-place jacketing. The paper wraps up with recommendations for further research on interface modeling, long term durability data, performance-based optimization, life-cycle assessment, and design guidelines for practical use.