Construction Control For Wide Box And Space-twisting Cable-stayed Bridge

Cable-stayed bridge is composed of pylon, beam and cable, which is higher statically indeterminate structure. It has big across capacity, beautiful appearance and flexible combination. Wide box girder and space-twisting cable plane is a special combination of cable-stayed bridge. Wide box girder has big width. The distance between two cables in transverse is biger than in longitudinal. Space-twisting is different from parallel and sector type. The longest cable is anchored the lowest position in the tower. In recent years, with the development of the urban landscape bridge, wide box and space-twisting cable-stayed bridge becomes more and more.This paper analyzed and studied the construction control of wide space-twisting cable-stayed bridge based on a practical engineering, aimed at exploring the very method of construction control for the cable-stayed bridge which has wide steel box girder and space-twisting cable, and finding out the adapted theory of computation, and providing reference and accumulating experience in construction control of the cable-stayed bridge. First of all, this paper introduced the origin and development of cable-stayed bridge and the construction control method of cable-stayed bridge and its development status. After that, the construction control method of cable-stayed bridge was elaborated in the paper. In the transverse camber calculation, we used the method of the separated section of cable support beam unit, and achieved good results. We used a variety of methods to calculation the reasonable cable force, and achieved the desired results. Specific construction control program is developed according to the construction program of the bridge, which including the working conditions of pre-assembled monitoring for steel box girder, pushing monitoring and the temporary pier monitoring etc. At last, we test the bridge state and properties of itself through load test, and inspect the construction control of the bridge.Construction control method used in this paper belongs to the adaptive control law. First, we get the calculated values of deformation, internal forces and other parameters of the structure for each construction stage by theoretical calculations, Sensors were arranged in the key position of the structure to collecting the corresponding parameters. Through comparing the measured and calculated values to judge the security of the structure and guide the construction. When the measured value is quite different from the calculated value, re-adjust the calculation model by taking the measured parameters of materials and structures into the model, repeatedly adjust the model until the two agree with each other. Then they can accurately predict the structure deformation and internal force of next construction phase. According to the results of calculation, construction control unit guides the next step of construction and predicts the effect of the construction. So they can make the construction toward a predetermined target, and ultimately achieve the design and construction control purposes.From the monitoring data and load test results, we know that cable force and the main beam linear are in line with the expectations, and the goal of construction control was achieved.