Seismic retrofit of shear walls with headed bars and carbon fiber wrap

A series of four shear wall specimens was tested in order to evaluate the seismic retrofit that had been proposed for the core wall of an existing building. The core wall had nonductile reinforcing details, including lap splices in the longitudinal reinforcement in potential plastic hinging regions, inadequate confinement of boundary regions, and inadequate anchorage of the transverse reinforcement. The seismic retrofit involved the use of headed reinforcement, carbon fiber wrap, and reinforced concrete collars at the base of the wall. The four shear wall specimens were tested under reversed cyclic loading. Two of these walls had a lap splice in the longitudinal steel at the base of the wall, and the other two had a lap splice 600 mm from the base of the wall. One of each of these specimens was tested in the as-built condition and the other two were retrofit prior to testing. The test results show that the retrofit strategies were successful in improving the ductility and energy dissipation of the shear walls.