Study Of Crack Width Of Slabs In Through Steel Truss Composite Bridges

Through steel truss composite bridge is a type of bridge structure, which deck system, main truss and concrete slabs bear the loads together though shear connector. Because of this, it can improve the strained condition of girder, strengthen the stiffness of the structure, and lower the building height. Through steel truss composite bridge is very suitable for high-speed railway.With the development of Chinese high-speed railway, it has wider usefulness. Compare with the RC constructure, through steel truss composite bridge has its feature because the cracks in the slabs are stricted by the shear connectors. Through steel truss composite bridge has applied on the high-speed railway in Japan, Germany and other countries. But the public information is extremely limited. In this paper, the impact factors of cracks are analysised Theoretically. The main works been done as follows:1. The mechanical characteristics of the through steel truss composite bridge is analyzed in the thesis by utilizing the large universal finite element software, ANSYS.2. From the cracking mechianism and cracking state in negative moment area,the documents about the widths of cracks are discoursed.3. According to the test data of, cracks on the traditional theory and finite element model are introducted. The impact factors of the cracks in the concrete slabs are discussed.4. The calculation of the crack width is analyzed, and a 64m through steel truss composite bridge is a example to compare.5. According to above-mentioned, the paper derived from the minimum ratio of reinforcement, and cracking moment considering the impact of shrinkage,and gives the the basic principles of the control of the cracks on design stage.