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.