Seismic behavior and numerical modelling method of RC beams subjected to freezing-thawing damage

To analyze the seismic response of reinforced concrete（RC）beams under frost environment，a series of accelerated freeze-thaw cycle tests were conducted on four RC beams in the artificial environment laboratory，and then pseudo static tests were carried out on all the specimens. The experimental results showed that the pinching effect of hysteretic curves was more evident and the ductility as well as the energy dissipation capacity of specimens degraded with increasing number of freeze-thaw cycles. In the meantime，the bond stress-slip model under freeze-thaw cycles was established through theoretical derivation. Then，the zero LengthSection of finite element software OpenSEES was used to in the numerical modeling of the seismic breaking process of RC frame beams，which was based on the fiber model incorporating the effects of freezing-thawing damage. According to the comparison results of numerical modeling and experimental investigation，the hysteretic curves obtained from finite element modelling was basically consistent with the test results；the differences between feature points of skeleton curves were relatively small；the pinching effect caused by freezing-thawing damage was well reflected in the modelling. Therefore，the proposed modeling method is accurate，which provides theoretical support for the research on the seismic performance of existing RC structures under freezing-and thawing environm