Construction Controling Technique For Yunnan Jindong Suspension Bridge

The core content of suspension bridge construction controlling technology is the alignment of the cable and main girder, suspender length and offset distance of cable saddle, etc. In this paper, based on the engineering background of a 730m span stiffening steel truss suspension bridge(Yunnan Jindong Bridge), the research on the key technique of construction controlling has been carried out.First of all, the evolution of cable erection technology and materials and the development of cable controling methodology has been reviewed in this paper. The content and process of suspension bridge construction monitoring and controling is summarized. The measuring point and adjustment scheme of the cable shape and truss stress for Yunnan Jindong Bridge is layed out.The cable is the keypoint of suspension bridge construction control, which is also the emphases of this paper. In the main cable segmental catenary method, the derived cable equation and iterative recurrence formula has been deducted combined with existing research. Considering the influence of the main cable saddle geometry, coordinate calculation formula of the existing cable saddle point is modified. The standard suspension geometry and internal force calculation process is improved, and on this basis, deductions of calculation methods of cable strand in different position for geometry parameters is done. According to this algorithm, program for the calculation of geometric parameters of the cable in finished bridge state is established by C language, and run on MATLAB. In this paper, the program results of author and the business program results are in good agreement with each other.Combined with Jindong Bridge, the construction monitoring content and calculation method of key parameters in main cable and stiffening truss and tower and constructed bridge state is given.The error tolerance for the influence parameters of suspension bridge has been analyzed. The results indicate that, elastic modulus of main cable and stiffening truss dead load error is not significant to unstressed length of main cable. As for Jindong Bridge, if the variety of Elastic Modulus is ±5%, the variety of non stress length of main cable is ±157mm. If the variety of dead load for stiffening truss is ±5%, the variety of non stress length of main cable is ±135mm. However, by setting the appropriate adjustment distance in anchor, the variety of non stress length of main cable can be accepted. The results also indicate that, environment temperature is significant to alignment of cable in the middle span, as for Jindong Bridge, the influence coefficient is -28mm/?. In side span, the influence coefficient of temperature is -3 mm/?.