Study On Analysis Method For The Rational Finished State Of Pedestrian Suspension Bridge With Wind Cable

Pedestrian suspension bridge is widely used for its advantages of long-span,beautiful bridge type and convenient construction.However,the wide-span ratio and height-span ratio of stiffening girder are smaller than those of highway suspension bridge,for its narrow width.In order to improve the stability of wind resistance of bridge,wind cables are often needed with large tension,which makes it complicated to determine its rational finished state than the traditional suspension bridge.Meanwhile,the influence of the inclination angle,rise-span ratio and the internal tension of the wind cable on the whole bridge is different.Considering the problems above,this paper has done the following studies based on the pedestrian suspension bridge of Daqingshan Forest Park in Zhangjiakou.This paper states the parabola and the catenary theory for shape finding of cable,giving an effective method for the calculation of the segmented catenary.The method is realized by MATLAB programming and used in the calculation of shape and internal forces of main cable of suspension bridge.The nonlinear FEM for calculating shape and internal forces of main cable is described..The iterative computation can be realized automatically when the allowable error is given.This method is efficient automatic and simple.It is convenient and effective for the calculation of suspension bridges.Adopting the unstrained cable length as control parameters,a iteration method of wind cable is proposed to calculate it’s shape.When the anchoring points coordinates and the total unstrained length of wind cable are specified,a control coefficient should be introduced in the iterative calculation to ensure that the total unstrained length of wind cable is constant.This method can calculate automatically by nonlinear finite element software,avoiding the problem of poor convergence caused by appointing the shape of wind cable to converge to a specified point.Step wise iteration method for the rational state of a pedestrian suspension bridge with a wind cable is proposed.This method iterative calculate successively,using the calculation of main cable and wind cable as two sub modules,outputting results until the finished state is rational.This method is used to calculate the pedestrian suspension bridge of Daqingshan Forest Park in Zhangjiakou The studies show that this method is,efficient automatic and simple,can consider the interactive influence between main cable and wind cable.It is superior to the multistep FEM iterative method by artificial operation.A lager number of finite element models are set up through the method above.The influence of wind cable with different inclination angles,rise-span ratio and internal force on the whole bridge is studied.The design principles of pedestrian suspension bridge with wind cable are given in this paper.