Shake table tests on prestressed concrete frames

Results from small scale models of prestressed concrete frames, tested by a shake table simulating earthquake forces are presented. The primary curves (horizontal force-displacement relationships) and the hysteretic loops are determined experimentally. Concrete strength is approximately between 32 a nd 84 MPa, and two types of effective prestresses are used, namely, 40 and 80 percent of the yielding stress of the prestressing bars. It is found tha t the effects of concrete strength and effective prestress on the ductility are significant because the ductility increases with increasing concrete s trength and with decreasing effective prestress, and the prestressed concre te frames may have at least a ductility factor of 8.0.