Construction Control Technology Of Long-Span Half-Through Arch Bridge

Half-through arch bridges not only retain the basic mechanical characteristics of overhead arch bridges,but also have simple and lightweight components that give people a sense of beauty.When the rise-span ratio is too small,this type of bridge can also meet the requirements of clearance under the bridge.Therefore,it is widely used in bridge construction in China.However,because of multiple system transformation throughout construction process,the construction control of half-through arch bridges has become an important part of the bridge construction process in order to ensure the construction safety of the bridge and make the maximum possible internal force and deformation of the structure close to the ideal design state.Based on the engineering background of the Quanhe Bridge on North Jiefang Road in Fuyang,this paper combines the mechanical characteristics of the half-through tied arch bridge and its development and research in the world to study and summarize the key technical issues of the entire construction control process.In this paper,the main researchs on the construction control of the mid-span arch bridge are as follows:(1)This paper briefly analyzes the mechanical characteristics of half through arch bridge,and briefly describes the development and research status of half through arch bridge at home and abroad;(2)The professional finite element software Ansys is used to establish the finite element model of the cap and tube cooling.Based on the basic principle of stress control,by analyzing the influence of cement hydration heat and concrete shrinkage deformation on stress during bearing platform pouring,the layout scheme of three-layer pouring and pipe cooling is determined;(3)The professional finite element software MIDAS Civil is used to establish the finite element model of Quanhe Bridge.According to the construction scheme,the formal installation analysis and simulation are carried out,and the structural checking calculation in the use stage is carried out,so as to obtain the variation rules of the displacement,internal force and stress of the structure in each working condition,so as to guide and optimize the construction scheme.The precamber and the precamber of the bridge are set according to the displacement of the bridge under constant load and vertical deformation under live load.(4)Through the monitoring of the internal force,stress,suspender force and linear shape of the structure during the whole construction process of Quanhe Bridge,it can be seen that after the suspender is stretched according to the optimized tension plan,the sections of the steel main girder and steel arch ribs will be The measured and theoretical values of stress are in good agreement.The errors of the measured and theoretical lines of each section of the main girder are all within 20 mm,and the deformation of the arch ribs is also within a reasonable range.The measured errors of the bridge suspender force and theoretical suspender force No more than 10%.During the whole construction process,the stress,alignment control and boom force of the structure are all within a reasonable range,and the control effect is good.It can provide basis and reference for the subsequent construction control of half-through tied arch bridge.