Research On Big-span Steel Box Girder Mechanical Characteristics And Construction Monitoring

In our country,incremental launching construction was mostly applied to build large-scale bridge.This method has advantages of not affecting traffic, reducing construction equipments, being helpful for production organization,reliable and shortening the construction period etc, But the stress of the main girder is more complex than other conventional construction methods in the process of incremental launching .Therefore, it is necessary to simulate the construction process.In this paper, we adopt the ANSYS software establish full-bridge model. simulating the steel box girder,steel guide girder,launching platform and temporary pier constraints and so on . And analyzing the whole process of steel box girder incremental launching, making analysis for the stress and the displacement of the steel box girder in the process of launching , which will become a reference for similar project construction.According to the structure of big span steel box girder,mechanical and construction characteristics and difficulties,Put forward the construction key technology of the steel box girder pushing control. The main work accomplished in this paper are as follows:⑴This paper summarizes the principle,characteristic and classification of the construction technolog,and intruduces the research situation of pushing method in domestic and abroad. Also summarizes the problems of steel box girder pushing construction.⑵T he mechanical characteristics and analysis method of long-span steel box girder was descripted in detail,and put forward the shortages of the simulation calculation software,which will be the basis of the stress of steel box girder. Combined with the characteristics of wuhan erqi bridge to introduce the process of the steel box girder pushing construction.And according to the characteristics of constructions todetermine the key points of monitoring and control.⑶Using the universal finite element software ANSYS to establish 3d simulation model of each working condtion of steel box girder launching,and according to the basic engineering material, identify the model parameters and select the reasonable unit.Then analyze the mechanical characteristics,stress,deformations and the reverse force of each pier.⑷Analyzing the results of finite element calculation to determine the factors of force of steel box girder in the process of pushing.⑸According to the actual construction process of pushing to put forward several monitoring measures,which are linear control, geometric monitoring and physical monitoring. And combined with the results of pushing simulation to get several precautions of erqi bridge pushing construction, which will be a firm foundation for subsequent construction.