Experimental Study On Bending Fatigue Behavior Of Prestressed Concrete Girders With Box-type Section Used In High-speed Railway

In recent years, High-speed railway construction has become the main trends in the development of our railway. In order to meet High-speed railway's stabilization and speediness, its form is complicated and special. However, the fatigue problem of prestressed concrete is also quite defective in comparison with conventional reinforced or prestressed concrete members.Based on a prestressed concrete girder with complex box-type section of 36m span, four models of 1/6 scale were made, and one of them was mixed with a kind of polymer latex. 1st models is tested by static test to determine the model of the cracking load and extreme load; 3rd is tested by low amplitude fatigue load(0.03Mu~0.3Mu),2 million later, loaded by the high amplitude load(0.07Mu~0.5Mu); 2nd and 4th models is tested by the high amplitude fatigue load(0.07Mu~0.5Mu).According to tests, fatigue failure pattern of flexural member is analyzed by experimental research on fatigue behavior of concrete girders with box-type section used in high-speed railway, and reinforcement strain and fatigue deformation are also mainly analyzed; the cracks development of concrete girders with box-type section used in high-speed railway is analyzed on the basis of these experimental results, and the influencing factors are discussed.The results shows that, in simulation of the train normal operation under the low amplitude fatigue load, the fatigue performance is satisfactory and the fatigue behavior under a subsequent larger cyclic load is similar with that one under the same big cyclic load. The polymer has no negative effect on fatigue behavior of the model.