Blast performance and analysis of reinforced concrete beams subjected to corrosion of the longitudinal reinforcement

This research has investigated the effect of reinforcement corrosion on the flexural response of reinforced concrete beams subjected to blast loading. Five beams, with and without corrosion, were tested under blast loads using a shock-tube. The corroded specimens were subjected to an accelerated corrosion regime prior to testing, with a mass loss of up to 22% in the longitudinal steel reinforcement over the mid-span or full-span regions. A companion set of two beams was tested under quasi-static four-point bending. The results from the static tests show that corrosion of the longitudinal reinforcement decreased the strength and ductility, and ultimately changed the failure mode from ductile to brittle. Under blast loading, the steel corrosion increased maximum displacements and support rotations, reduced blast capacity, increased damage and fragmentation, and led to more brittle failure as the % mass loss increased. The effects of corrosion on blast response were moderate when the steel was corroded over the full-span region. Furthermore, the blast response of the beams was predicted using dynamic inelastic single-degree-of-freedom (SDOF) analysis, with the resistance functions developed using 2D finite element modeling, while accounting for the reduction in steel stress-strain properties and corrosion-induced cracking. The SDOF analysis showed acceptable results in terms of ability to predict maximum displacements of the flexural-governed beams (corroded and un-corroded).