No.0 Block's Spatial Stress Analysis Of PC Continuous Box-girder Bridge With Cantilever Casting Construction

The cantilever construction method is commonly used in long-span PC continuous box-girder bridge. As the initial beam segment of the box-girder poured by cantilever,the structure and stress of the NO.0 block are very complex.Especially,the volume of the NO.0block is much bigger than other.In general,the model of beam element is often not able to reflect its true three-dimensional stress state. And the NO.0 block is the foundation of the cantilever casting construction of each beam segment in the future. The construction quality of the NO.0 block is related to the quality of the whole bridge. So it is very important to analyze the spatial stress accurately in the construction and completion stage. In this paper,the following work have been done:(1) The engineering situation of Sioma bridge and the emulation process of construction stage are introduced. The beam-column element of the main beam is established by the finite element analysis software Midas Civil. The stress is calculated and analyzed under different working conditions of the structure of the box-girder bridge.(2) The NO.0 block's spatial analysis model of the box-girder bridge is established by Midas FEA. The process of establishing the structure and the management of boundary conditions are described in detail.Then analyze the spatial stress stage of the NO.0 block in the process of cantilever casting construction and completion stage. Finally,according to“Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts”JTG D62-2004 on the relevant requirements of crack check.The normal and diagonal section of the NO.0 block are carried out crack check.(3) Simulate the exothermic process of hydration of cement after pouring the NO.0 block of the box-girder bridge by the general finite element analysis software ANSYS. The temperature field and thermal stress of the NO.0 block are analyzed after pouring.The temperature stress and the concrete's early tensile strength are compared to verify whether temperature are produced or not.