INELASTIC SEISMIC RESPONSE OF PRECAST CONCRETE FRAMES WITH CONSTRUCTED PLASTIC HINGES

A modified seismic design concept is introduced for precast concrete f rames in which beam plastic hinges with reduced yield capacities are c onstructed away from the precast beam-column connections arranged at t he column faces. Plastic hinge location and yield capacity are employe d as the basic parameters of an analytical survey in which the inelast ic dynamic responses of a conventional precast frame and its modified counterparts are calculated and compared under two earthquake excitati ons by using a general purpose computer program for dynamic analysis o f inelastic frames [1, 2]. An optimum design is obtained by providing plastic hinges on precast beams located at one depth away from the bea m ends, in which primary (negative) bending moment yield capacities ar e reduced between one-third and one-quarter of the beam design end mom ents. With such plastic hinge configurations, precast beam-column conn ections at the column faces can be designed to remain elastic under st rong earthquake excitations.