Optimization Of Closing Scheme And Analysis Of High-Pier And Long-Span Continuous Rigid Frame Bridge

The high-pier and long-span continuous rigid frame bridge is a multi-hyperstatic and complex spatial stress system, and it has many influence factors. The formation of final structure will have a complex process of system transformation, and it has limited adjustment measures to adjust the completed structure during its construction. Therefore, it is particularly important to carry out the structural analysis of the high-pier and long-span continuous rigid frame bridge at design phase. Based on the Pingzhai Bridge in Guizhou province, which is a high-pier and long-span continuous rigid frame bridge with 235 meters'main span, the analysis and closing scheme optimization were carried out in this thesis. Some work and achievements are followed:(1) This thesis analyzed the alignment and mechanical behavior during its construction and service stages of Pingzhai Bridge under permanent action, variable action and combination for action effects.(2) This thesis analyzed the concrete shrinkage and creep action effects of PC continuous rigid frame bridge, and then some useful conclusions for design were drawn.(3) This thesis analyzed the uniform temperature action effects and gradient temperature action effects of concrete box girder. In addition, this thesis analyzed the influence of uniform temperature action effects on prejacking force scheme, and its conclusions can provide a theoretical reference for the design and construction.(4) Based on the measured temperature data, this thesis analyzed the temperature distribution of thick concrete box pier in the sunshine in Guizhou region, and then the temperature gradient mode at the time of largest thermal difference was fitted with the exponential function according to the domestic and foreign specifications and empirical formulas. Further more, this thesis analyzed the stress of a high concrete pier under measured temperature gradient, and then some useful conclusions for the design and construction were drawn.(5) Numerical simulation of plane temperature field on the concrete box pier was carried out with the finite element pragram ANSYS, and its theoretical results fit well with measured data, so it will be an effective method to study concrete temperature field on the condition of lacking measured data. (6) This thesis proposed two other common closing schemes on the basis of the original design closing scheme, and then compared the influence of different construction closing order on the alignment and stress of structure, finally a closing scheme that can make the alignment and stress of structure most rationable was determined.(7) Firstly, the necessity of measure of prejacking was studied in this thesis.Then the influence matrix methosd was proposed to optimize the prejacking force, and then a prejacking force scheme that can make the stress of structure during its construction and service stages approach rationable was calculated by combining the influence matrix method and bisection method.