Research On Structural Parameters Of The Double Cable Suspension Bridge

Due to the double cable suspension bridge in the aspect of dynamic performance is better than that of single cable suspension bridge, combined with the development and construction of double cable suspension bridge is slower and the single cable, this paper targeted research with double cable suspension bridge structure parameters on its static characteristics and dynamic effects.This paper based on Guantou Dam double cable suspension bridge, used the finite element analysis software Midas/Civil to construct the engineering example of the model. By adjusting the parameters of the bridge, we found the data of static and dynamic characteristics which under the controlling parameter. Induction and analysis of the data, the conclusions listed as following.Static features:(1) from the perspective of main tower internal force influence, the generally link way between tower and beam is the most advantageous way;(2) under the condition of consolidation link between beam and tower, the stiffening girder can get the minimum value at its middle span position;(3) under the condition of the cable tower consolidation, bottom of tower will produce huge hogging moment that is much larger than the slip link one;(4) the increase of suspension Bridges span ratio can effectively reduce the cable side span stress, and also can reduce the anchoring end bearing reaction force;(5) increasing the rise-span ratio of the double cable suspension bridge can obviously reduce the internal force of bridge tower, cable’s stress, and improve the bridge tower stress, but its overall vertical stiffness is smaller, and the value of middle span will increase.Dynamic features:(1) as the rise-span ratio decreases, the vibration frequency of double cable suspension bridges’lateral bending, vertical bending and twist will increase, as soon as it beyond one rise-span ratio, its rising velocity will decrease;(2) under the condition of keeping other parameters constant, in order to modify the double cable suspension bridge tower beam constraints can be found that different ways of constraints on its natural frequency of vibration has a great influence, generally the freedom degrees of tower beam is inversely proportional to stiffness and the frequency,(3) under the condition of different constraint of cable and tower, keeping other parameters constant, the natural frequency of vibration of double cable suspension did not changed anymore;(4) span ratio on the double cable suspension bridges had no effect on the natural frequencies of vibration, as well as its stiffness;(5) as the increase of the vertical stiffness of the stiffening girder longitudinal beam, the vibration frequency of double cable suspension bridges’lateral bending, vertical bending and twist will obviously increased. Combining research and analysis, we can drew the conclusion that the link way between tower and beam, the link way between cable and tower, the rise-span ratio of the practical engineering are relatively reasonable.