Failure mechanism of RC beam under reversed cyclic loading after flexural yielding caused by lateral strain accumulation in plastic-hinging region

摘要

The purpose of this paper is to show the existence of a new shear failure mode which is caused by reversed cyclic loading after flexural yielding. Under reversed cyclic loading, shear-resisting system in the plastic-hinging region repeats temporary disappearance and rebuilding. The temporary disappearance is caused by temporary opening of all the cracks just after changing loading direction. The temporary disappearance generates residual lateral strain in the plastic-hinging region. The increase in the residual lateral strain expands the temporary disappearance and the expanded temporary disappearance generates more lateral strain. This failure mode is caused by the abnormal expansion of the temporary disappearance condition due to rapid increase in the accumulated lateral strain. The occurrence of this failure mode is considered to be defined by a divergence condition of the lateral strain accumulation under reversed cyclic loading.