Study On Structure Behavior And Reasonable Span Arrangement Of Multi-span Continuous Irgid Frame Bridge With Super High Piers

Because of the advantage of the structure continuous, strong crossing capacity, lessexpansion joint of the bridge and comfortable driving, the application of PC continuousrigid frame bridge is used widely in the highway and city bridge. By the restrictions oftopography, landforms, geological conditions and the route elevation, piers of the PCcontinuous rigid bridge built in the mountains are getting higher and higher. The highpiers bring many problems to the design, construction and the later-period management.In the way of design, the first of all is the problem of the reasonable layout of the piersand the span. When the height of piers reduced, the bridge span will be certainlyincreased, while the long span in existing concrete system is a difficult breakthrough. Inthe construction and service phase of the bridge, affected by the prestressing loss andthe shrinkage and creep, the deflection of the girder is increased, and the displacementsof piers are produced.Based on the project of Guizhou provincial department of transportation Designand construction key technology research of Hezhang continuous rigid frame longbridge with super high piers (2010-122-017), the follow research works were done:①The bending moment and girder corner formulas of multi-span continuous rigidframe bridge with uniform sections are derived by the displacement method of structuralmechanics, and the bridges with uniform sections divided into different numbers ofspans are compared through these formulas. Based on the Hezhang Bridge, theinfluence of the proportion between side span and middle span, the height of piers onbearing forces and deformations were studied. Then this paper put forward the relativelyreasonable span arrangement.②According to the current specification JGT D62-2004in China, prestressingloss and deflection of the girder were calculated. In addition, using Midas/Civil, thispaper analyzed the girder deformations and piers displacements of multi-spancontinuous rigid frame bridge produced by shrinkage and creep of the concrete.③This paper studied the variation regularity of stress and deflection of eachcontrol section of continuous rigid frame bridges with different bottom curves ofbox-girder respectively under conditions of the gravity, lane loads and loadscombination which contain prestress.④The spatial entity finite element model of segment No.0of Hezhang bridgemain pier was constructed in this paper, and studied the temperature field and thermal stress produced from the heat of the hydration in construction. Meanwhile, the spatialstress under construction and completion is analyzed by considering the prestressingforce and concrete’s shrinkage and creep.