Stability Analysis Of Large Slope High And Low Tower Cable-stayed Bridge With Inter-tower Cables

The large-slope high and low tower cable-stayed bridge with inter-tower cables had unique structures and novel shapes,and it had the characteristics of large inclination of bridge tower,self-importance,and asymmetric cable between two towers.Whether it can meet the stability requirements during construction and use had become a question worthy of careful analysis,especially in the construction stage,its stability was not only related to the bridge structure itself,but also closely related to the construction load and temporary support.If the construction plan was not handled properly,the bridge may be unstable.Shou Chun West Road Bridge was the first largeslope high and low tower cable-stayed bridge with inter-tower cables in China.In order to ensure the safety of the construction and use of the bridge and prevent damage due to instability,this dissertation combined the actual problems that occurred during the construction of the bridge,the finite element software was used to analyze the stability during construction and used in detail.The main research contents and conclusions were as follows:(1)The finite element software was used to establish the simulation model of the construction phase to determine a reasonable construction plan,and the stability of the entire construction phase was analyzed.According to the construction characteristics of the bridge,the overall stability of the four typical construction phases(the completion phase of the hanging rope,the closing phase of the main tower,the closing phase of the auxiliary tower,and the second stage of constant load)were studied.The results showed that the stability of the bridge during the construction stage generally decreases with the continuous advancement of the construction process.The stability of the structure was the lowest at the completion of the cable suspension,and the minimum stability coefficient was 13.10.During the closing phase of the main and auxiliary towers,the stability of the structure was greatly improved.During the secondphase dead load phase,the stability of the structure was decreased.(2)According to the construction characteristics of the bridge,the impact of temporary support,construction load,and construction procedures on the stability of the construction stage was analyzed,and the effect of the structural parameters of the bridge itself(stiffness of the tower,dead load of the tower,cable force between towers,cable area between towers,stiffness of main beam)on the stability of the construction phase was analyzed.The results showed that temporary support and construction procedures had a significant impact on the stability of the construction phase.Reasonable temporary support and construction procedures were conducive to improving the construction stability of the structure.Construction load and main beam stiffness fine-tuning within a reasonable range had little effect on the stability of the construction stage.The stability coefficient during the construction phase was positively related to the stiffness of the tower and the area of the cable between the towers.The stability coefficient during the construction phase was negatively related to the dead load of the tower and the cable force between the towers.(3)The finite element software was used to establish the simulation model of the bridge-forming stage.According to the change trend of the stability coefficient of the bridge-forming stage under different load combinations,and the effects of live load and across-wind load on the stability of the bridge formation were analyzed.The influence of structural parameters on the stability of the bridge-forming stage was analyzed.The results showed that the live load had less influence on the stability of the structure.The across-wind load had little effect on the stability of the structure.The stability factor at the bridge completion stage was positively related to the stiffness of the tower,the area of the cable between the towers,and the stiffness of the main beam.The stability factor at the bridge completion stage was negatively related to the dead load of the tower and the cable force between the towers.