Comparative Study of Seismic Behavior of Multistory Reinforced Concrete Framed Structures

Abstract

A comparative study of the nonlinear behavior of reinforced concrete (RC) multistory structures is carried out on the basis of measured response of four six-story, three-bay framed structures, namely a regular bare frame, a discontinuous-column frame, a partially masonry-infilled frame, and a wall-frame system. The structures were designed for similar seismic requirements in accordance with Eurocode 8, and their 1:5.5 scaled models were subjected to similar earthquake simulation tests. Experimental observations and numerical analyses show that the distribution of the story shear overstrength is a rather stable indicator of the general inelastic behavior of frames, and hence, can be employed as a characteristic parameter to quantify the frame irregularity for design purposes. Abrupt discontinuity of the geometry or arrangement of structurally effective elements, where unavoidable, may be compensated by strength enhancement targeting a smoothed overstrength profile to allow for distributed inelastic deformation, and this principle applies as well to nonuniformly masonry infilled frames. For the wall-frame system, adequate countermeasures against rocking of the RC wall is shown to be a key to maintaining the effectiveness of the system at advanced inelastic response.