Geometric State Control For Bridges Constructed In Stages

Phased construction method of bridge structure has been widely employed in bridge construction for its high efficiency and quality,low cost,high material utilization,and tiny impact on and environment.The continuous changes in the geometric state of the components during the installation process of the bridge using staged construction are prone to errors,and may even be accompanied by a certain degree of construction risk,which in turn affects the completed state of the structure.At the same time,traditional component construction control methods are difficult to visually display the changes in the geometric state of components and check the theoretical accuracy of component construction parameters.It is not conducive to clearly grasp the precise geometric state of the component construction process.Therefore,this paper is based on the accurate calculation and analysis of the key construction parameters of the component installation process,and at the same time,it uses Revit's parametric modeling technology to quickly establish a model that simulates the precise matching of component geometry.Finally,the geometric state of the bridge structure is accurately analyzed and predicted,and the geometric state is controlled.The research is mainly carried out from the following aspects:(1)This method is based on the idea of smooth docking of the interface between the segments during installation,and the relative positional relationship between the installed segments and the to-be-installed segments is determined according to the true cumulative deformation produced by the structure.According to the relative position relationship,the matching and cutting parameters between the components at the actual interface are calculated,and the blanking parameters of the components are determined,thus realize the exact geometric matching between the components.It can calculate the geometric installation parameters of the actual construction process of the bridge rigid components constructed in stages.It is also suitable for the parameter correction of the adjacent cross-sections between the non-stressed and stressed components in the whole process of the rigid component construction.At the same time,it provides guidance for the smooth assembly and geometric state control of small and large sections.(2)This method based on the catenary curve theory,the analysis ideas and calculation methods of the anchor point coordinates,unstressed length,cable force and other control parameters of the stay cables in each construction state are sorted out,and the geometric conditions of the stay cables are further analyzed and predicted.Considering the construction errors of the anchor point coordinates,sleeve inclination angle,cable force and other structural characteristic parameters may affect the geometric state of the cable,the risk assessment of the corresponding errors is carried out to provide reliable data support for the pre-plan of the cable construction process.The control parameter analysis and error evaluation of the geometric state of the cable construction process can carry out precise two-way identification and control of the cable force and cable alignment.It can also ensure that the geometric shape and force state of the cable during the construction process are in a controllable range.(3)The research is based on Revit parametric modeling technology,and combined with the theoretical analysis method of the geometric state of the bridge component construction process.As a result,the construction process of the rigid component and the flexible component geometric state is efficiently and accurately simulated.The matching of components,structural deformation and linearity are visually displayed.The theoretical accuracy of the component parameters is checked.This makes the geometric status of the bridge's phased construction process clearer and more intuitive,ensures the smooth implementation of the construction process,and further provides a foundation for the realization of bridge digital construction.