Seismic vulnerability assessment of reinforced concrete bridge piers exposed to chloride-induced corrosion

Existing reinforced concrete (RC) bridge piers located near the sea are vulnerable to corrosion phenomena that might negatively affect the load-bearing capacity of the overall bridge, especially under seismic loading. It is of primary importance to assess the seismic vulnerability of existing RC bridge piers under different corrosion scenarios, in order to quantify the reduction of the seismic structural safety induced by these frequent material degradation phenomena. This contribution deals with an experimental-numerical procedure for the seismic vulnerability assessment of corroded bridge piers. The procedure is illustrated in the context of the Zappulla multi-span viaduct (Sicily, Italy), whose RC piers are experiencing chloride-induced corrosion. A comprehensive quality control is conducted, including carbonation tests, corrosion potential mapping and extraction of corroded steel bars for tensile tests, in conjunction with SonReb tests and concrete coring. The test results are critically interpreted to calibrate a numerical fiber-hinge model of the bridge pier, through which numerical seismic analysis is performed under two different corrosion scenarios. It has been found that the seismic safety margin of pier structures is reduced of up to 20-40% by taking into account a mass loss in percentage of the steel bars equal to 20-30%, as suggested by experimental findings. (c) 2023 The Authors. Published by Elsevier B.V.