Study On Shear Behavior Of RC Beams Strengthened By Carbon Textile Reinforced Concrete Plates

The Textile Reinforced Concrete(TRC)is a new kind of strengthening material,which includes fiber fabric and cement matrix.TRC has good mechanical properties of fiber fabric,and can maintain good bonding hehavior with concrete.Therefore,TRC can effectively enhance the bearing capacity of concrete structures.Prefabricated Textile Reinforced Concrete plates(CTRC plates)is a kind of prefabricated TRC material,in this paper,the prefabricated Carbon Textile Reinforced Concrete plates(CTRC plates)is used to enhance the shear capacity of concrete beams.Based on the three-point bending test,the shear capacity of CTRC plates is studied,on this basis,the shear capacity of the RC beams strengthened with CTRC plates is studied by three-point bending test,and the corresponding theoretical research is carried out.,the following results have been achieved.(1)Increasing the thickness of CTRC plate can enhance the bond performance between fiber fabric and cement matrix,which is beneficial to exerting the str ength of fiber fabric.When the thickness is 10 mm,the shear capacity increases by 25.4% with the increase of the number of layers of fiber fabrics from one to two;when the thickness is 20 mm,the corresponding increase is 50.8%.The shear capasity of CTRC plates under three point beading test is calculated,the experimental value is in good agreement with the theoretical value.(2)CTRC plates can significantly enhance the shear capacity of reinforced concrete beams.Compared with the control case,the increase of shear capacity of strengthened RC beams is ranging from 55.8% to 83.4%.In terms of failure modes,the failure mode of the control case is shear failure,while the failure modes of the strengthening cases are shear failure of the RC beams,and accompanied with debonding failure between the TRC plates and concrete beams.Additional anchorage measures can improve the strength utilization of fibre fabrics,enhance the initial stiffness of the reinforcement conditions,and reduce the extent of debonding between the TRC plates and concrete beams.Based on the test results,the strength utilization ratio and unit stiffness of CTRC plates are analyzed.The results show that the strength utilization efficiency of CTRC plates are more than 50%,and the unit stiffness of the CTRC plates is greater than that of the RC beams,which ensures the strength ultilization of CTRC plates.(3)Based on truss arch model,the theoretical formula of RC beams shear strengthened with CTRC plates is deduced.By analyzing the concept of effective strain of fibre fabrics in existing models of concrete members strengthened with FRP,the strength reduction factor of fibre fabrics in CTRC plate is proposed,the deduced formula for calculating the shear capacity is revised by this coefficient,and a more reasonable theoretical result is obtained.