Seismic performance of precast concrete column-to-column lap-splice connections

摘要

Implementation of precast construction for buildings requires connection techniques that can speed up the process by requiring only simple and easy on-site activities, while still guaranteeing satisfactory strength, stiffness and ductility. The construction method should reduce the use of formwork and temporary bracing, avoid aesthetic problems and be compatible with the lifting capacity available, but at the same time avert an increase of costs that could threaten the viability of using precast concrete. In the case of columns, the use of single story segments connected above and below the beam-column joints is an alternative that reduces the element weight and overcomes several problems that may appear when the column segments are connected at mid-height between stories. This alternative, however, requires splicing the reinforcement at a location where rotational demands may induce inelastic behavior, which is deemed inadequate by procedures stated in several design codes, unless proven otherwise. In response to this, a beam-column joint, splicing the reinforcement at the column ends, is herein proposed and tested under cyclic loading to evaluate its behavior and the possibility of using this technique to build moment resisting frame structures in seismic regions. The results from the precast column-to-column connection were compared with those from a similar cast-in-place unit with no splices. Results show that the behavior of both units are comparable, with just slight differences in the cracking, damage distribution and hysteretic behavior, so that the use of the proposed precast column-to-column connection may be considered appropriate.