Nonlinear dynamic analysis of RC structures based on moment-curvature relation

Abstract

The nonlinear dynamic responses of RC frame structures under earthquake excitations are usually developed at certain critical regions, and these regions are often located at points of maximum internal forces such as the beam-column joints. This means that an accurate numerical model, which can simulate the hysteretic behavior of RC columns and beams, is necessary in order to exactly predict the nonlinear response of the frame structures. To make numerical model, the determination of influence factors which affect to the nonlinear response at a joint is essential step in the construction of an numerical model. Typically, initial stiffness, bond-slip, anchorage slip, and axial force effect are some of the influence factors which must be included in the numerical model because the major sources of deformation in RC frame structures are flexural rotation, shear deformation including shear sliding, and bond-slip. The hysteretic load-deformation behavior of frame member arises from a combination of these deformation mechanisms. Many analytical models have been proposed to date for the nonlinear analysis of RC frame structures, and these range from very refined and complex local models to simplified global models. Of these models, an numerical model based on the moment-curvature relation is popular used in the case of frame structures. Such models include cyclic stiffness degradation and further modifications to take into consideration the pinching effect due to the shear force and the strength degradation after yielding of steel. In addition, by using the bilinear hysteretic curve instead of trilinear, a more simplified model has been proposed. Nevertheless, these models still have limitations in simulating exact structural behavior of RC columns because of the exclusion of the bond-slip, fixed-end rotation effect, axial force and Bauschinger effect. This dissertation concentrates on the introduction of a moment-curvature relation of a RC section that can simulate th...