Engineering Controls Of Rigid Frame-Continuous Girder Bridges And Parameter Sensitivity Analysis

With the rapid development of the national economy, the cause of the bridge is undergoing enormous changes:the bridge span is getting longer and longer, the upper structure is lighter, carrying capacity is getting stronger. This profession high-speed development in this industry today. Rigid The rigid frame-continuous combination beam bridge as a popular bridge type has been widely used because it combines the advantages of the continuous rigid frame continuous beam bridge.The rigid frame-continuous bridge’s construction mainly uses the cantilever construction method. Being a statically indeterminate structure system of rigid frame-continuous girder bridge with complex forms of stress, and increased lots of difficulty to the construction of the structure. In order to guarantee the construction process is safe and smooth. construction control was introduced in the construction process, and gradually became an indispensable means of control. This article take the Xiaoxiang bridge as the project example background, introduced the rigid frame-continual system bridge development course as well as the tendency, describes the origins and the better and better process of project control in the bridge construction process. And the detailed elaboration earlier period project monitoring plan arrangement to the later period implementation process, including the construction summary analysis, formulated the corresponding monitoring program according to the construction characteristic, could well reflect the construction process the structure stress characteristic, guaranteed the structure satisfied this conditions in linear, the stress, the stability and the safety performance.Meanwhile analysis to the construction control result, including stress and deflection data comparison between theory and practice, confirmed the validity and accuracy of the construction control process.Finally carries on the sensitive analysis of parameters to the Xiaoxiang bridge, there is many factors affect the state of structure during the construction, such as elasticity modulus of the structure, volume weight of the beam section, construction loads, creep and shrinkage and the prestressed load etc. The task of structure parameters of sensitivity analysis is to ensure the parameters which greatly influencing the behavior of bridge construction. The exactly operation method is change the value of parameter in a certain range, based on the change rate of the structure linear date to distinguish main parameters and the secondary parameters. The analysis results indicate that among the design parameters which influence the linear of Xiaoxiang bridge, volume weight is the most important parameter which cause main girder’s deformation; loss of prestressing take second place; elasticity modulus of the structure is the third important parameter; ambient humidity, prestressed pipe deviation, prestressed friction coefficient construction loads, creep and shrinkage is so little that can be ignored.Because of the influence that the relative density prestressed steel layout and the change of beam section’s size, different part has different sensitive degree of influence parameters:part1/4th span which has the densest prestressed steel layout, the parameter sensitivity are the largest; part1/2span has the smallest section size, but lost some prestressed steel, so sensitive degree is decreased; because the restrictions by pier top, caused this part of the beam has the largest rigidity, the parameters of the sensitivity of the lowest. Last, Temperature load impact on bridge linear is also greatly, in the process of construction we should take tried to avoid in general.