Study On Design Calculation And Construction Research Of 400m Cantilever Casting Reinforced Concrete Arch Bridge

More than a few long-span reinforced concrete arch bridge have been constructed by cable-stayed cantilever casting.The 384m under-construction Almonte Bridge in Spain is currently the largest span cable-stayed cantilever casting reinforced concrete arch bridge.However,at present,there are only 5 arch bridges built by cable-stayed cantilever casting,and the largest span is only 240m(Guizhou Shatuo Bridge in Yanhe,Guizhou Province).The span of the cantilever casting arch bridge is further expanding,which will become a favorable competitor for the large span bridge in the mountains.Therefore,the research on the technology of cable-stayed cantilever casting at long-span concrete arch bridge has a practical significance and theoretical application basis for promoting the development of bridge in our country.In light of the above background,this paper tries to design and research the 400m cable-stayed cantilever casting reinforced concrete arch bridge.Specific research work:1.This paper summarizes the development status and research status of the cable-stayed cantilever casting reinforced concrete arch bridge,and makes a technical basis for the development of the cantilever casting arch bridge in the direction of large span.2.Based on the mathematical statistics and analysis of large-span reinforced concrete arch bridge built at home and abroad,this paper puts forward the reasonable design parameters of 400m cantilever casting arch bridge.Besides,this paper determines the main arch's section used 12m wide and 6m high variable thickness of top and bottom plate of single-box space structure with twin-cells,and studies the influence of different rise-span ratio and arch-axis coefficient on the stress and displacement of bare arch to obtain the reasonable value of design parameters.3.By collecting the reference data of the building structure and arrangement form of large-span concrete arch bridge at home and abroad,comparing and analyzing the bridge calculation with different parameters of main arch and studying the influence of the self-weight and its structure on the force and displacement of the main arch of the bridge,the final program with rise-span ratio 1/6,arch-axis coefficient of 1.988 and the spandrel structure of steel-concrete composite beam is determined.4.By studying the construction technology of the cantilever casting arch bridge and combining with the actual situation of the design scheme,this paper determines the construction steps that the section 1#uses cast-in-place bracket while the rest of the section adopts the cantilever casting until the construction of the fastening frame.On this basis,this paper uses the zero-displacement method and the stress-balance method to calculate the reasonable cable force of the cantilever arch bridge and uses the forward analysis on construction process of the arch bridge to verify the feasibility of the construction.Besides,this paper makes the research on the cable tension,arch ring deformation and stress variation in the process of hanging the arch ring around the length of the cantilever and the height of the deduction,and gets:The increase of the height and the decrease of length of the cantilever can reduce the tensile stress and the cable tension of the arching.The tensile stress of the 10m section is 0.7 MPa bigger than 5m,and the cable tension is 1860kN bigger.When the tower height increases 40m,the cable force of 17#reduces 15%than the original cable-tower scheme;And when the tower height reduces 20m,the maximum tensile stress of the construction stage of arch is 2.2MPa,while the tower height increases 40m,the maximum tensile stress of arch is 1.3MPa.