EXPERIMENTAL STUDY ON RESTORING FORCE MODEL OF CIRCULAR RC PIERS STRENGTHENED WITH PRE-STRESSED CFRP BELTS
To study seismic behavior of circular RC piers strengthened with pre-stressed CFRP belts,seven circular RC piers were tested with the main experimental parameters being lateral pre-stress level of CFRP belts and axial load ratio.Test results show that the diagonal shear cracks of piers can be effectively confined with the active lateral confined stress provided by pre-stressed CFRP belts,and the failure mechanism of the piers may be changed from shear to flexure with satisfactory ductility.By analyzing the effect on the hysteretic characteristics of the piers strengthened under different conditions,a series of hysteretic rules for piers strengthened are suggested;Using theoretical analysis and statistic regression analysis,the formula for flexural capacity is presented,and the methods to calculate characteristic parameters of skeleton curves are proposed,as well as a series of hysteretic rules for piers.The three-line restoring force model of circular RC piers strengthened with lateral pre-stressed CFRP belts is set up,which is capable of considering lateral pre-stress level of CFRP belts and axial load ratio.The result of the model shows good agreement with the test result.