Construction Control Analysis Of PC Cable-stayed Bridge With United Twin-tower

The cable-stayed bridge is widely used in our country with the development of traffic construction. The structure updates constantly and a new kind of cable-stayed bridge with united twin-tower is developed in recent years. Compared with ordinary cable-stayed bridge, the two towers are rigidly connected, which contributes to the stability of the whole structure. Based on the practical engineering of a united twin-tower cable-stayed bridge, focusing on the characteristic of the unsimultaneous construction, this paper studied the construction of the united twin-tower cable-stayed bridge.The whole unsimultaneous period was simulated through finite element method and the cable force and the template elevation are obtained. The cable force obtained from calculation conformed well to the cable force provided by the design institution, with an error less than 5% and outline satisfied well to the design requirements. Parameter analysis was conducted based on least-squares method and the elasticity modulus as the sensitivity parameter and the beam volume-weight were finally determined. The new theoretical elevation extracted from the model modified using the identified parameter conformed well to the elevation measured from the real bridge.The pre-camber was modified after the analysis of the influence of the different construction process. The results showed that the unsimultaneous construction had some effects on the elevation and cable force of the previous 5 segments before closure. Besides, the displacement of the lagged beam in closure reached 40 mm and the corresponding cable force of completed bridge reached 5.9% compared to simultaneous construction beam.Analysis of the effects of unsymmetric construction of the suspended beam(one-sided pouring segments and one-sided tensioned cables) was conducted. The results showed that the displacement of the suspended beam on the other side reached 27 mm under the condition of unsymmetric pouring. At the same time, one-sided tensioning would lead to a maximum displacement of 114 m on the other side. Therefore, unsimultaneous construction, especially near closure, should be avoided.The positive results acquired in this paper may provide reference for the construction control of united twin-tower cable-stayed bridge.