Research On Application Of Key Measurement And Control Technology In Upper Structure Construction Of Extra Large Suspension Bridges

With the continuous development of infrastructure capabilities and the actual development needs in China,currently the suspension bridge develops in the direction of increasing span,which makes it increasingly difficult to do the construction work.The construction of upper structure is a key part of the entire suspension bridge.Thus,this paper takes the monitoring survey of a super-large suspension bridge upper structure construction as an example,and get some useful conclusions through the analysis and discussion of the following aspects.(1)Relevant technologies and methods for retesting the control network of the bridge are described and summarized.In particular,the impact of instrument vertical angle measurement system error which failed to completely compensate on the elevation difference is discussed,when doing the long-distance river-crossing trigonometric leveling using an intelligent measuring robot.In response to this problem,effective solutions have been proposed from various aspects such as field observation methods and data processing,aiming at further improvement of the accuracy of river-crossing trigonometric leveling;(2)Analyzed and discussed key measurement work of upper structure before its construction,including the deformation regular pattern with temperature changes of the bare tower and the determination of its datum position.In addition,the author discussed the problem of elevation measurements of datum strand cable and other structure could only be measured with unidirectional trigonometric leveling and the unidirectional measurement range is more than 1km.Firstly,the practicability and advantages and disadvantages of several methods for measuring atmospheric vertical refractive index were analyzed.And according to the actual condition of the datum strand cable elevation measurement,determined the method to correct unidirectional elevation difference by calculating the refractive index based on precise elevation difference.Then,before actual measurement and adjustment of the datum strand cable elevation,a unidirectional trigonometric leveling correction experiment was performed according to the selected method.The experimental results show that this method can be used to measure the elevation of datum strand cable of extra-large suspension bridges;(3)Based on above preparation,takes a datum strand cable elevation measurement and adjustment of extra-large suspension bridge as an example,the author integrated the optimized measurement and data processing methods form a complete and reliable datum strand cable elevation measurement program.The measurement and stability observation results of the elevation of the datum strand cable proved that this method is stable and reliable.And the result also shown that the control precision of the datum strand cable meets the design accuracy requirements.Thus,it can provide some reference for similar projects;(4)Finally,software of data processing and management was created which used to improve the efficiency of datum strand cable absolute elevation measurements.