The Nonlinear Analysis Of Cables Broken Accident And Recovery State Of A Cable-stayed Bridge

After carried out reform and open policy, the Chinese economic aggregate increased year by year, and our highway construction industry has been developing rapidly. The development of cable-stayed bridge, which is most often used to across the sea and river, made a significant contribution to our highway construction. Nearly three decades, because of unique and beautiful shape and the superior crossing ability and other characteristics, the cable-stayed bridge has been rapidly expanded in China.The long span cable-stayed bridge is high indeterminate structure system. When applied the load in general form, the cable-stayed bridge will produce larger displacement, and the structural geometry position will also be obviously changed, so the mechanical characteristics of cable-stayed bridge is flexible, and it has significant geometric nonlinear behavior. This paper, taking the cable broken accident in the construction phase of a long-span cable-stayed bridge as engineering background and using the finite element software——abaqus, analysed geometric nonlinear behavior of the cable broken process and the recovery process. After the cable broken accident, the concrete occurred a wide range of cracking, so this paper also involves analysis of the corresponding concrete material nonlinearity. Through the above calculation and analysis, this paper discussed the mechanical state of this cable-stayed bridge after the accident and the restoration effect in the recovery process of tensioning temporary cable.By numerical simulation, this paper found that, after the broken of some left side cable in the big mileage direction, the force of cable in the big mileage direction sharply increased, and the left side cable faring away from tower has a trend to be broken; the main beam in the big mileage direction appeared large subsidence, and the middle section of this beam appeared serious contortion, thus the subsidence of left side main beam is larger than right side, and the contortion produce a wide range of brittle cracking of the concrete in this region; the tower present counterclockwise rotating(viewed from above to bottom). After the rescue of tensioning temporary cables, the cable-stayed bridge has been basically out of dangerous, and the cable force of the cable-stayed, displacement of main beam, deviation of the main tower and so on has been greatly recovered. After full-recovery of the force of temporary cable, the internal force and deformation is different with the bridge state of before the cable broken accident, but the difference is small, and compared to the bridge state after the cable broken, the cable force of the cable-stayed, displacement of main beam, deviation of the main tower and so on has been further greatly recovered.By comparing the calculation results with the actual measurement, this paper found that, the calculation results after the accident is close to the actual measurement results, but there are non-ignorable differences between the calculation results in the recovery process and the actual measurement results, and the reason of the differences is that this paper used the plastic damage of concrete to simulate actual brittle cracking of concrete, applying reverse load, the plastic damage deformation can not be recvered, but the actual cracks can be closed. So there are differences between the cable-stayed bridge state in the recovery process of calculations and the actual state.