Mechanism Of Strengthening RC Beams With TRM

Textile reinforced mortar(TRM)is widely used as a new kind of composite reinforcement material with high strength and corrosion resistance.The key point of TRM material application is how to accurately evaluate the bearing capacity of RC structure strengthened by TRM,and the reinforcement effect of TRM material and the failure mechanism of RC structure reinforced by TRM are closely related to the interface adhesion characteristics of TRM-concrete.Therefore,the theoretical study of the bearing capacity of TRM-reinforced RC structures was carried out based on the results of TRM-concrete interface stress analysis,providing theoretical and experimental references for the practical application of TRM-reinforced RC structures.And the main contents and conclusions of this paper are as follows:(1)The double shear test of TRM-concrete interface was carried out to study the force distribution and failure type of the bond interface.And the relative slip failure mechanism and evolution law of bond interface were analyzed.Based on the double shear test data,the relative slip relationship of the bonded interface was proposed.(2)The bonding mechanism of the interface was discussed by using elasticity.Compared with the experimental results,the interfacial shear stress at the end was greater than the actual bearing capacity,but the effective stress area of the interface was smaller than the actual value,indicating that the elastic theory analysis cannot evaluate the bond strength of the interface by the mechanical properties of the bond.Therefore,the penetration of the TRM on the concrete surface cannot be ignored.(3)On the basis of the elastic model and the relative slip relationship,the overall strength of the interface was used to quantitatively analyze the bonding layer,and the mechanism of interface failure was analyzed from the perspective of damage.It was pointed out that the bonding interface is usually composed of elastic zone,damage zone and stripping area.Besides,the interfacial stress distribution was deduced theoretically using this model,showing the calculated results were consistent with the actual values.(4)The bending process of six TRM-reinforced beams was used to analyze the failure process and morphology.And the finite element analysis of the test beams were carried out by using the concrete plastic damage model and the cohesion model,indicating that the final theoretical values were in agreement with the actual values.(5)Based on the analysis results of interfacial stress and the assumption of the section,the bending capacity and crack characteristics of the test beam were theoretically analyzed and the calculation formula was proposed.