Elasto-Plastic Seismic Response of Reinforced Concrete Frame

Step-by-step numerical integration method developed and applied to determination of response to digitized record of N-S component of the 1940 El Centro earthquake of a typical New Zealand 6-story single-bay reinforced concrete rigid frame, assuming idealized elasto-plastic moment-rotation properties for beam and column members. Elasto-plastic responses are compared with extended elastic behavior. It is shown that although character of elasto-plastic responses is similar to extended elastic predictions, magnitudes of maximum displacements are significantly greater in extended elastic cases. Plastic deformations are found to concentrate in weakest members. It is shown to be possible to restrict yielding to beams and base of bottom columns by having relatively low yield moments at these sections. Member ductility requirements are shown to be quite small, only barely exceeding 6 in one case.