Seismic vulnerability assessment of RC bridge piers strengthened with GFRP rebars: A case study

The use of Glass Fiber Reinforced Polymer (GFRP) bars for retrofitting bridges piers under seismic excitation is an advanced technique that offers several benefits due to the material’s unique properties, in terms of high strength-to-weight ratio, insensitivity to corrosion, and high durability. Throughout the world, a large number of outdated structures, particularly those made of reinforced concrete, require urgent repairing interventions due to a variety of factors, including environmental effects, inadequate construction details, and neglected maintenance. Engineers who want to increase the longevity and safety of bridge structures in seismic regions can find great benefits in the application of GFRP. An existing bridge is considered as case study. The strengthening design strategy aims to increase the lateral resistance by slightly altering the lateral displacement ductility. To this aim, a hybrid retro-fitting with steel and GFRP rebars is designed to be applied through the jacketing technique. The force-deformation curves of the nonlinear plastic hinges are determined using a fiber approach, after validation of the constitutive models. A Pushover Analysis (POA) with lumped plasticity is implemented in order to compare the seismic response of the original structure with the retrofitted one. The capacity of the structure and thus its Seismic Vulnerability Index (SVI) and differences in overall structural response areevaluated.