| Precast frame systems represent an economic alternative for building construction in regions of high seismicity. Advantages of precast concrete over cast-in-place concrete include superior quality control, speed of erection, and aesthetic architectural form. However, this system is not widely used in the US because framing methods and connections between precast elements suitable to US construction practices have not been adequately tested, and as a result, there is a lack of comprehensive design recommendations. The primary objective of the research program described herein is to develop precast beam-column connections for use in seismic-resistant structural frame systems which (1) require minimal or no cast-in-place concrete, and (2) are economical and ductile. The different types of connections considered in this program are (1) tension/compression yielding, in which energy is dissipated through inelastic behavior of the connecting elements, (2) friction connections in which energy is dissipated through friction when slip occurs between connecting elements, and (3) nonlinear-elastic in which energy dissipation is minimal but the advantage is the small residual drift following ground movement. Four half-scale models of prototype precast beam-column connections subjected to reversed cyclic loads have been constructed and tested. Load-deformation responses for complete connections and connecting elements, load-strain response for select connecting elements, as well as comparison of energy dissipation, residual drifts, and stiffness will be presented. Based on the behavioral information collected during connection tests, analytical models were developed to investigate the behavior of complete precast frame systems. |
