Abstract
The aim of this paper is to know the nonlinear behaviors of reinforced concrete panels subjected to cyclic shear forces, which can be used for the analysis of reinforced concrete structures like shear walls. Here the authors performed many tests of RC panels with parameters of reinforcement ratios and loading patterns. The panels were loaded with monotonic or cyclic in-plane shear forces by using a newly developed testing facility with automatically controlled 24 closed loop hydraulic actuators and a network of links. From the measured data of deformations and forces average stress-strain relationships of cracked concrete were calculated referring the Collins and Vecchio's study. The obtained results were investigated concerning the differences of nonlinear behaviours of cracked concrete between monotonic loading and cyclic loading. The main results are as follows. 1) Shear capacities in cyclic loads were reduced a little, compared with monotonically loaded cases. 2) The tension stiffening characteristics of concrete are dependent on reinforcement ratios and loading patterns. 3) Cyclic behaviours of cracked concrete are estimated such as residual stress and strain, slip stiffness in low stress states and the accumulation of residual strains caused by the expansion of panels, or dilatancy. When modelling the compressive state of concrete, such characteristics should be evaluated. These results are the fundamental features which will be used for proposing analytical models.
