Determination Of Reasonable Completion Cable Force And Construction Cable Force Of Asymmetric Single-Pylon Cable-stayed Bridge

Cable-stayed bridges have become the first choice for long-span bridges due to their large spanning capacity,beautiful bridge shape,and good economic benefits.At the same time,the long-span PC cable-stayed bridge is also a bridge type that is more difficult to design and construct.In its design work,it is an extremely critical step to determine the reasonable completion and construction status of the bridge.Based on the existing cable force optimization research,this paper takes a single-tower asymmetrical prestressed concrete cable-stayed bridge as the engineering background,and focuses on three aspects:reasonable calculation of bridge cable force,reasonable construction cable force calculation,and auxiliary pier construction process force.The main research contents are as follows:1)The finite element software Midas/Civil was used as the platform to build a simulation model,and the initial bridge completion state was obtained according to the minimum bending energy method.Then the unknown load coefficient method based on the influence matrix was used to optimize the bridge cable force,and the reasonable bridge completion state was obtained.The feasible region of the dead load moment of the main girder was obtained by the stress balance method,and the bending moment of the main girder,the stress of the main tower of the main girder and the stress of the cable under the optimized completed bridge were checked.The feasibility of this method for determining the reasonable completed bridge state was verified.2)With the reasonable completion state of the bridge as the goal,the construction stage of the formal installation is analyzed,and the formal iteration method and the formal installation difference method are respectively used to calculate the reasonable construction cable force.By analyzing the convergence rate of the cable force,the cable force error,the bending moment after iteration and the deflection of the main girder after iteration,it is proved that the formal iteration method is more reasonable than the difference iteration method to simulate the construction state.According to the construction state obtained by formal assembly iteration,the stress of bridge tower and main girder is checked from the maximum double cantilever state,maximum single cantilever state and completed bridge state,and the validity of solving reasonable construction state by formal assembly iteration method is verified.3)Under the guidance of reducing the amount of weight concrete and on the premise of maintaining the pressure of the supporting force of the auxiliary pier,two improved construction schemes are put forward according to the construction process.The counterforce at the auxiliary pier,the stress of the main beam of the side span cast-in-place section and the maximum compressive stress of the support column are compared and analyzed between the two improved schemes and the original design scheme.