The Research Of The Polymer Mortar And Prestressed Strand Flexural Strengthening

In recent years, with the rapid development of Chinese bridge construction, there are series of world-renowned bridges, Hangzhou Bay Bridge and Shantou Bay Bridge are both in the world seven famous Bridges; At the same time, some of the bridges constructed in the early years begin to age, and the trucks are overloaded, it can be a definite impact on the safe operation of the bridge, for example, Cracks exceeding limit, and excessive deflection caused by insufficient bearing capacity of bridge structure, so the department and design department need to pay attention to bridge maintenance.This paper solves the problem of insufficient bearing capacity of highway bridges and city bridges, proposed to impose the small-diameter of prestressed strand to the hollow plate girder and T-beam girder bottom. And improving the carrying capacity of the old bridge with the polymer mortar on the prestressed strand. This paper studies the new method to strengthen the old bridge which puts forward in recent years, and it’s different from other reinforcement methods, which have many advantages:Small-diameter Steel strand anchors easier, which can reliably pass prestressed; Polymer mortar can reliable bond beam with strand together. With the role of anchor and prevent corrosion of prestressing tendons, it can extend the durability of the reinforcement system; Prestress applied to cause the inverted arch of the bridge to a certain extent, and it can reduce the internal forces caused by the weight, so it can increase the safety performance of the bridge.Through the theoretical analysis combined with practice, using ANSYS software, we study the influence of the reinforcement system. And validated by experiments, we test eight beams with different number of prestressing strand, different tensioning control stress and different polymer mortar, the test played a better effect from testing the deflection, stiffness and comparing analysis with contrast beams with steel reinforcement beam; At the same time, strand reinforced method which is used on the testing bridge strengthening design, through the load test before and after reinforcement data analysis, we get the expected results. Research shows that, the polymer mortar and prestressed strand method can improve the bearing capacity of old bridge, and it can improve the original bridge mechanical performance, which can shrink the structure cracks of the bridge. Polymer mortar can extend the life of the steel strand, whose durability is better, the method has certain economic significance, the cost is only2/3of the cost of steel reinforcement method, saving our social resources.