Research On Construction Technology Of Long Span Reinforced Concrete Slab Arch Bridge Support

Arch bridge is a bridge type widely used in bridge engineering.The solid slab arch bridge with concrete and reinforcement as the main building materials is called reinforced concrete slab arch bridge.In the construction technology of slab arch bridge,bracket construction is a common construction method in China and has been widely used.However,the support structure of reinforced concrete slab arch bridge with large structural span,high support height and large bearing weight are not common in China.The bearing capacity,stiffness and overall stability of the support structure are the key to achieve the goal of building a slab arch bridge.Therefore,it is necessary to ensure that the support is in a stable state in the process of concrete construction,and the construction control such as support preloading and settlement observation is in a controlled state.Taking a deck type reinforced concrete slab arch bridge in Donghe District of Baotou City as the engineering background,combined with the main arch ring with a span of 75 m,solid slab arch with slab thickness of 1 250 mm and support erection height of 23 m,this paper makes a qualitative comparative analysis on different support forms suitable for the engineering characteristics,including the bearing capacity,stiffness,overall stability and support foundation The design checking calculation is carried out,the preloading program of the support is designed,and the settlement observation is carried out according to the specifications and design requirements in the actual preloading process,and the construction technical procedures such as concrete pouring,crack control,and scaffold unloading in the construction stage are designed.Through the research and analysis of these contents,the following conclusions are drawn.1)Through the qualitative comparison and analysis of braced thick steel pipe arch,steel arch and full hall steel pipe arch,combined with the construction site and geological conditions of the project,the bowl buckle full steel pipe arch is determined as the support structure of plate arch.2)Through the bearing capacity,stiffness and overall stability of bowl buckle type full-length steel pipe support,the stress analysis and design calculation of the support foundation are carried out.The check results meet the requirements of the specification,which provides a reliable theoretical basis for the safety of subsequent slab arch construction.3)Through the design of three-level loading program for the arch,the settlement observation was carried out for 14 days according to the design requirements after the completion of all load loading.The settlement,total settlement,elastic deformation and inelastic deformation of each observation point were counted.The accumulated maximum settlement of each observation point was 5mm.According to this,it can be judged that the arch frame designed is safe and reliable,which provides an effective theoretical basis for the construction of arch ring,and eliminates the unsafe factors in the construction process of arch ring concrete.4)The checking calculation of the side pressure of the arch ring side formwork ensures that the deformation of the formwork is relatively small in the concrete construction;the reasonable design of the pouring procedure of the arch ring concrete can avoid the adverse influence on the arch frame during the construction;the safety standard demolition of the arch frame ensures the safety of the construction.