Research On Construction Monitor And Control Technology For Pre-stressed Concrete Curved Continuous Rigid-Framed Bridge With Long Spans And High Piers

In recent years,with the expressway construction spread to mountain areas,lots of prestressed concrete(PC) curved continuous rigid-framed bridge with long spans and high piers need to be constructed.The bridge integrated with the characteristics of high pier, long span and curve,its construction technique is difficult, its internal force and deformation in construction are more complex than the straight bridge, monitoring and effective controlling in construction are important conditions of ensuring construction safety and quality.Meanwhile, there are many differences between the construction monitoring and controlling of the bridge and the straight bridge.Based on Guan-Shi river bridge in Macheng-Wuhan expressway in Hubei, this paper research on the technology of construction monitoring and controlling for PC curved continuous rigid-framed bridge with long spans and high piers, and to provide reference for construction monitoring and controlling for the bridge. The major contents of this paper contain:(1) Summarized the development of long spans PC continuous rigid-framed bridge, curved girder bridge and research situation of construction monitoring and controlling for PC curved continuous rigid-framed bridge with long spans and high piers at home and abroad, expounded the structural and mechanical characteristic of PC curved continuous rigid-framed bridge with long spans and high piers,and introduced the basic theories of construction controlling for long spans bridge.(2) Applied structural finite element analysis software MIDAS/Civil to simulate and analyse the construction process of Guan-Shi river bridge, changed the curvature radius and analysed the construction process of continuous rigid-framed bridges of different radius, comparativly analysed the influencing factors to internal force and deformation of curved continuous rigid-framed bridge with long spans and high piers,such as height of pier, circle angle, the dead load, prestressing force, temperature effection, concrete shrinkage and creep.(3) Elaborated the corresponding method for alignment controlling combined with the deformation characteristic in construction of PC curved continuous rigid-framed bridge with long spans and high piers. The bridge not only need to install vertical pre-camber to control vertical alignment,but also should install horizontal pre-camber from pier construction according to horizontal displacement of high pier, axis alignment control and distortion control for curved box girders should be strengthened,horizontal pre-camber and torsional pre-camber should be setted up during the cantilever constrruction.(4) Measuring point of stress monitoring in construction of PC curved continuous rigid-framed bridge with long spans and high piers should be arranged according to the stress on section of curved box girder. Analyse the main factor of influencing stress testing.The correcting methods for eliminating temperature effect and concrete shrinkage and creep are applied in practice, and achieved good results. The measures to control prestress tension for the bridges are proposed.