Seismic rehabilitation using precast infill walls

Many existing reinforced concrete moment-resisting frames located in seismic zones lack strength and ductility. One approach for correcting these deficiencies is the construction of infill walls to strengthen and stiffen the structure. Cast-in-place construction is often used; however, there are conditions where cost, time constraints, or limiting disruptions to building operations may dictate other solutions. One possible modification is the use of infill walls constructed of precast concrete panels.; A precast infill wall system eliminates the need for large formwork during construction. Elimination or reduction of connection hardware between precast panels or between panels and the existing frame element can provide additional efficiency. Problems associated with casting large quantities of concrete in an existing building are eliminated. Construction time and inconvenience to occupants may be reduced along with the costs.; Three phases of experimental research were conducted. The first phase was investigation of the precast panel to panel connection. In the second phase, the precast panel to existing frame connection was studied. In both phases, direct cyclic shear tests were conducted to determine minimum details for satisfactory connection performance. The third phase consisted of testing a large-scale model specimen. The test specimen, a two-story nonductile frame infilled with precast panels was used to evaluate the overall system behavior, verify performance of connection details, and investigate the performance of post-tensioning used to provide column tensile capacity at the boundary elements of the wall.; Design and detailing guidelines were developed to enable designers to use the precast infill wall system as an alternative to cast-in-place construction. The precast system has the potential of reducing the overall costs of rehabilitating existing structures.