Experimental Evaluation of Performance Criteria for Reinforced Concrete Beams under Cyclic Loading

To assess the performance criteria of the reinforced-concrete, five-storey residential buildings common in Iran, an experimental study in the structural laboratory of the University of Tehran has been conducted. The test program includes cyclic and monotonic load tests of six beams that represent three-to-five storey buildings with rigid frame structures. Using definitions given in FEMA-356 and ATC-40, stages of immediate occupancy, life safety, and collapse prevention have been identified on the drift- force curves of all specimens. Based on the test results, values of the plastic rotation, ductility, strain in concrete cover and in longitudinal bar, crack width, damage index, and length of plastic region at different levels have been determined. It was found that the recommended values of plastic rotation and ductility for reinforced concrete beams by FEMA-356 are conservative. The length of plastic hinge region in the stage of immediate occupancy is about half the plastic hinge length in the stage of life safety and it increases by 20% from life safety to collapse prevention