Simulation Analysis Of System Transformation Process Of Self Anchored Suspension Bridge And Study On Mechanical Properties

In recent years,self-anchored suspension bridges are more and more popular with the government and construction units because of their beautiful linetype,novel appearance and flexible location.Up to now,dozens of self-anchored suspension bridges have been built and opened to traffic in China.The construction control of suspension cable tension and main cable saddle pushing during system transformation is very complex,and there are few construction units and monitoring units with this construction performance.In order to obtain a reasonable system transformation scheme,this paper takes a self-anchored suspension bridge in China as the engineering background,and carres out the Optimization Research on the analysis effect of the suspension tension scheme for the system transformation.The main achievements of this paper are as follows:(1)The basic theory of MIDAS/Civil 2017 calculation and analysis of self-anchored suspension bridge is introduced,and the reasonable completion state of the bridge is determined.The reasonable completion state of the bridge is the target state of the loading analysis.The finite element simulation analysis of its construction process is carried out by using this software.(2)A simulation method of suspension tension by stages,i.e.changing the temperature of cable element,is used to simulate the tension of suspension by stages.The tension process of the suspension cable is realized by changing the stress-free length of the suspension cable element and changing the internal force of the suspension cable element by applying the load of raising and lowering temperature to the suspension cable element.During the whole process of tensioning a suspension cable,if it can be tensioned to the stress-free length of the completed bridge at one time,then the unit temperature of the suspension cable need not be changed;if it can not be tensioned to the stress-free length of the completed bridge at one time,the heating load should be applied to the suspension cable at the early stage of tensioning and then at the later stage of tensioning.The suspension element gradually exerts cooling load and stretches it to the stress-free cable length of the completed bridge.(3)Three kinds of cable tension schemes for a self-anchored suspension bridge in China are made,and the analysis results of these three schemes are compared and analyzed.The third scheme is to use 8 jacks,side and mid-span slings to tension at the same time,and the main saddle to push four times.This scheme adopts the step-by-step method.In addition to 15(21),16(20),17(19),the other slings need to be tensioned only once,which improves the efficiency of sling.(4)In the background of scheme 3,the influence of cable tension and saddle pushing on the displacement of main cable joints is obtained through calculation and analysis,and the influence of cable tension on the displacement of adjacent tensioned and non-tensioned main cable joints is obtained.The influence of cable tension on the displacement of main cable joints far away from tensioned and non-tensioned main cable joints is also obtained.The influence law of saddle pushing on the displacement of main cable joints in Side-to-Middle span is also discussed.(5)In the background of scheme 3,the influence law of cable tension and main saddle push on the change of cable force is obtained through calculation and analysis,and the influence law of cable tension on the change of cable force adjacent to and far from the tensioned cable is obtained,and the influence law of main saddle push on the change of side-to-middle-span cable force is obtained.