Static Analysis For Curved Extra-dosed Prestressing Continuous Rigid Frame Bridge

Continuous rigid frame bridge which possesses good integrality, excellent seismic performance, anti-torsion potential, concise bridge style, sophisticated construction technology etc, has proceed large scale construction in domestic engineering circles. However, with the growth of using time, the bridge structure shows some shortcomings, such as too large down deflection of mid-span, cracking of superstructure etc. In order to eliminate the above-mentioned drawbacks, it is adopted at present that increasing the quantity of prestressed reinforcement configuration, setting camber, and improving the method of closure segment's closure are in the the process of design and construction. It is not only increasing the construction cost but also generating other drawbacks, for example bursting crack or crushing in the bottom slab of box girder will happen when cantilever construction develops to the stretching for second stage steel tendons of bottom slab.The extra-dosed prestressing has been introduced into continuous rigid frame bridge in this paper, which considers several parameters about down deflection of mid-span caused by shrinkage and creep, including environmental average of humidity, magnitude of prestressed, flexural rigidity of girder. It is compared and analyzed that down deflection of mid-span of extra-dosed prestressing continuous rigid frame bridge and continuous rigid frame bridge has been caused by shrinkage and creep, when above-mentioned parameters change. At the same time, the maximum cantilever status of background bridge has been analysed on three-dimensional space stress, in order to obtain the distribution and transmission rules of bridge in axial direction normal stress corresponding to cross section. Finally, different structural design parameters of superstructure and substructure, including the length without cable of girder, ratio between side span and main span, central angle of girder, bending-twisting stiffness ratio of girder, and height of main pier, have been selected in order to carried out static analysis for curved extra-dosed prestressing continuous rigid frame bridge under the action of moving load, and obtain changing rule and conclusion about internal force and deformation of control section for this kind of bridge type.Hope that the results of this study could be reference for design and application in the curved extra-dosed prestressing continuous rigid frame bridge.