Research On Construction Control And Simulation Of Prestressed Concrete Railway Continuous Beam Bridge

The prestressed concrete continuous box-girder bridge which is built with the method of cantilever cast-in-place construction is widely used in public transportation system such as urban road, highway, railroad and high speed railway. It has become one of the most important construction style in bridge engineering. In order to insure the structural safety, construction quality and the line shape smoothly in the construction process and the operation time, the beam deflection, main section stress should be predicted and predominated. Application of soft-computing and monitored control system are applied to insure the construction quality.First of all, some construction control analysis theory and method are briefly introduced, then a finite element cantilever construction model is built using beam element. The modeling procedure is presented in detail, and the girder nodes' displacement and section stress are formulated right after.Secondly, the main influence factors such as volume weight of concrete, elastic modulus, prestressed load and cradle load are analyzed to find out which is the key factor to elevation control. And then the key parameters of the finite element model are modified according to the analysis and the field experiment. After the nodes' displacement is recaculated, the initialize heights of girder during construction is obtained respectively. Then, the gray prediction model is introduced to forecast new elevation height.Thirdly, the section stress is measrued by the strain sensor laid in the concrete during the construction stage, the stress development curved lines are plotted subsequently. Then Comparative Analysis on the Theoretic calculation and the measure results. The stress safety in construction process can be observed by this method, meanwhile, measurement and theoretic calculation error analysis can also be performed. The basis of the stress monitor is provided by this method.Finally, the pressure sensor is designed for the experiment on the friction loss of prestressed dust with Ansys statical analysis. The actual friction coefficient and deviation factor are caculated according to the experiment data using the method of least square. Compared with the specifications and the prestressing force tension procedure can be controlled through the experiment data.Overall, the simulation of the construction process is basically in agreement with the experimentally measured results and the bridge building construction is steadily controlled by this mixing method.