Constructional Monitoring And Shear Lag Effects Of Large Span Continuous Girder Bridge

In recent years, with the rapid development of transport, pre-stressed concrete continuous girder bridge has grown up to one of the primary bridges with its predominance of riding comfort and long span, and cantilever construction has already became the main method in long span bridge construction. Concrete volume-weight, pre-stress load, temperature, construction loads and so on makes a cantilever beam constantly change. In order to ensure the normal bridge closure and the ideal alignment of structure, it is necessary to analyze the upper part of the structure construction mechanical features and control the construction process.In this paper, we take the Liu yang river bridge of north road as engineering background, combined with design requirements and construction features, using finite element analysis software to precisely simulate the construction process, analyzing the internal force and deformation of each cantilever casting phase. During the process of monitoring, we test a number of sensitive factors, research these sensitive parameters effects the linear of the main beam. The comparative analysis result indicates that the sunshine temperature obviously effects on the structural properties. construction control and deflection measurements are required to avoid this temperature effect.Monitor the deformation of various parts of the bridge structure is important way to ensure a smooth close up as well as the linear of bridge structure meet the design requirements. With the conduction of the construction segment, the error occurred on the construction beams have been almost impossible to eliminate, and with the elongation of the cantilever, the accumulated error of a variety of factors have become increasingly evident, so the projections for the next phase of the state appear to be particularly important. In this paper, stating implementation of the Liu yang river bridge deformation monitors, and specifically using the gray control theory in the construction monitoring. As a result, the closure error is high precision, smooth linear, indicating the grey theory in continuous bridge construction control has a strong practical."Shear lag effect" has always been a great concern issue in bridge engineering. First, this paper studies the 3-bar simulation method in solving the variable cross-section continuous beam shear lag coefficient, and then, for the characteristics of variable cross-section of liu yang river bridge, discuss the factors of web and bottom effects the shear lag.The end, take the greatest cantilever construction state as the research object, using the APDL language of ANSYS, developing a prestressed structural analysis program to study the effect of pre-stress on the shear lag effects. prestress has a great influence on the structure properties, spatial finite element analysis is needed for complex cross-section, and pre-stressed cables should be optimized,making uniform cross-section stress.