Monitoring Of Construction And Test Under Vehicle Load For Large Boxed Girder With Cantilever Assembled Spines

In recent years, Highway solves the increasingly high traffic jam in most domestic major cities, which is a leading form of achieving three-dimensional rapid transportation system. As to the 1470 meters long traffic bottleneck on 4th Xingang Road in Tanggu district of Tianjin, it is located on the cetral line of Hebei Road in the east then crosses Kangzhen Road, Center Road and Northern Fujian Road, at last falls to the ground 100 meters to the east of Northern Road Xianzhuang Station Crossroad. For solving the latitudinal traffic conflict among Tientsin, Tianjin Economic Development Area, Protective Tariff Area, Tientsin harbor and the longitudinal traffic conflict in TangGu district, on the bridge structure's sculpt, this paper systemically compares their excellence and disadvantage of various routine bridge structure. In order to effectively ensure traffic capacity of accomplished roads, the author puts forward the idea of assembling post-tension prestress large-scale continuous spine box girder with some 5.8-meter-long cantilevers. During the cantilever assembling stage, because the structural geometrical speciality, material characteristic, construction load carried and boundary condition often unevenly change, structure system usually converts. Furthermore, due to the influence of the mechanism of concrete shrinkage and creep, internal force and distortion of each stage are unconventionally complex. For the sake of actualizing the effective control during the construction, and by the construction monitoring and track test of the finished dead load state of three spans post-tension prestress concrete large-scale continuous spine box girder, this paper provides the tracing and monitoring of each pivotal sectional box girder's stress,deflection and crack throughout the Constructing and dead load Stage of Construction Project. So we can gain the actual stress distributing of the girder , behavior of the girder and the bearing capacity of the spine beam bridge, then compare and analyze these results with correlative criterion and designal premise which the bridge follows. Accordingly, correctness and advancement about the bridge's design, dependability and security of the bridge's construction are validated. In the end, to improve the design and construction, some advice on the problem that appeared during the construction are given.