Study On Real-time Control Technology Of Arch Rib Alignment Of Cantilever Assembled Arch Bridge

Cantilever assembly method is one of the common construction methods in arch bridge construction in china.For the long-span arch bridges,the main arch segment hoisting and cantilever assembly is a dynamic and complex process,which is easily disturbed by external factors.If not controlled,the error will accumulate gradually,which makes it difficult for the main arch ring to successfully install.Therefore,it is necessary to control the construction of the main arch segment hoisting.In recent years,for the arch bridge constructed by cantilever assembly method,a series of studies have been carried out on its alignment and stress control by relevant scholars,and fruitful results have been achieved.However,the law of error transmission and the degree of error influence on the alignment of arch ribs still need to be study further,and the alignment control of arch ribs tend to controlled by a given error limit,which makes the discrimination efficiency is low and inaccurate.Therefore,this paper takes Jiangkai River Bridge as the research object,and carries out the following work:(1)In view of the complexity and inaccuracy of the current calculation method of cable force of cantilever assembled arch bridges,an optimization algorithm for cablestayed buckling construction based on stress-free state method is proposed.In view of the inaccurate alignment control and inefficient discrimination of arch rib segments,the "pre-elevation method of feasible region",i.e."the pre-elevation feasible region" and the "safety zone of buckling force",is proposed to carry out the dual control study of pre-elevation and buckling force of segment hoisting.(2)Around the arch rib alignment error in the construction control of cantilever assembled arch bridge,the error transfer rule is studied,and the influence of typical error factors on the arch rib alignment is analyzed.The main design parameters affecting the alignment of arch ribs are sensitively analyzed,and the error parameters are identified and corrected.(3)By comparing the two methods of adjusting arch rib alignment in construction,i.e."Intersection cushion steel plate" and "adjusting cable force",studies the internal force state of arch rib under different schemes,and considers that the arch rib joint should avoid filling steel gasket to adjust the installation elevation of arch rib as far as possible.(4)The method of "pre-elevation in feasible region" is applied to construction control and proposed that the alignment of arch rib is reasonable when the pre-elevation of segment and the cable force are respectively controlled in the feasible region,and vice versa.After that the real-time identification of the alignment of arch rib installation can be realized.At the same time,the safety of the cable is guaranteed by calculating the adjustment range of the buckling force in the safety zone of the cable force.Then combined with grey system theory,the prediction mechanism of arch rib installation alignment is studied.