The Construction Control Of Zhangjiakou Jianshe Bridge

The main cable of Self-anchored suspension bridges is anchored at the end of the main girder. The horizontal component of main cable is counteracted through make main girder become pressured, so self-anchored suspension bridges eliminates of the need of huge anchorage by this way. So the self-anchored suspension bridges have good economic benefits. ZhangJiaKou JianShe Bridge is a twin tower three span self-anchored suspension bridges. Its main tower is reinforced concrete structure; the main girder of the bridge is separate steel box girder, so the cross-section of the main cable is smaller. Based on ZhangJiaKou JianShe Bridge, this paper studies the theory and method of self-anchored suspension bridges construction control. The main contents cover the following aspects:1) We studies and introduce the calculation theory and method of suspension bridges, including elastic theory, deflection and finite displacement theory at present. The main shape is neither parabola nor catenaries. Main cable configuration of complete is segmental catenaries. Using the analytic modal based on segmental catenaries theory, we calculated the free length of each main cable, the hanger length, free cable configuration, the saddle pre-offset are also calculated and the position of each rope is determined. The influence of error factors such as cable length change, temperature change to the main cable erection configuration, this work offers theoretical guarantee to erection of main cable.2) The construction control method is determined by considering many various factors. Excellent method can not only assure the structure safe during system conversion, but also can shorten the duration. The construction control of self-anchored suspension bridges should assure the security force of main girder an main tower, and make sure that the there is not relatively slip between main cable and saddle. In addition, excellent method requests that the less tension rounds the better.3) This paper introduces free stress state control method, and builds a closure modal. The modal simulate tension by change the free stress length of hanger. And we propose two options based on ZhangJiaKou JianShe Bridge. By comparing these two options we find that the second option is much better.