Research On Cable Force Determination And Optimization Of Long Span Basket Type Arch Bridge

At the same time as the times continue to progress and develop,the bridge type of the tied arch bridge has also been widely used in the construction of bridges in China.It is the key to find a reasonable set of cable force for the tied arch bridge.Especially the sudden break of the short boom directly affects the safety of the bridge.The optimization of the cable force of the boom has always been a hot topic in the engineering field.Therefore,the research on the cable force of the tie rod arch bridge is very far-reaching in theory and practice.In order to carry out a more in-depth analysis of the theme,this paper takes the project of “130m basket arch bridge of Qinshui River Bridge” as an example,and determines and optimizes the cable force of the bridge boom of the basket arch bridge and determines the initial tension of the boom.the study.main tasks as follows.(1)Based on the 130 m basket arch bridge of the Qinshui River Bridge,based on Midas/Civil,a relatively scientific and perfect finite element model was established.For the determination of the cable force of the bridge of the Qinshui River Bridge,the method of rigid boom method and zero displacement method is mainly adopted.When the rigid support continuous beam method is applied,the mid-span deflection of the tie beam is 8.59 cm,and the bending moment of the tie beam is not in the form of positive and negative alternating,so the rigid support continuous beam method is not suitable for this example.The zero displacement method used in this example is more discrete and has a larger value.The cable force calculated by the minimum bending energy method is smaller than that calculated by other methods.The analysis shows that the bridge cable force determined by the minimum bending energy method is more reasonable.(2)Select the minimum cable energy method to calculate the initial cable force of the bridge,and use the Midas/Civil program to optimize the cable force of the group;fully consider the current situation of the short boom and analyze the influencing factors,the equal frequency.This idea was effectively utilized to successfully obtain the bridge boom force,and then optimized with the Midas Civil program to determine the final bridge boom force.The analysis shows that the internal force of the arch rib and the tie beam is closely related to the size of the cable force of the boom.The optimization of the cable force of the arch rib and the tie beam and the distribution of the cable force of the sling are considered.Uniform or not,the last choice is to make the cable force of the boom with better full-bridge strength as the target boom force.(3)The initial tension of the boom of the basket arch bridge can be determined by various methods,such as the inverted method,the dressing iterative method,the stress-free state method,etc.As for the cable force change of the boom,it must be special in the actual construction process.Pay attention to it and examine it in detail.It can be seen from the data obtained by the three methods that the initial tension values of the booms determined by the three methods of the bridge are similar,and the change trend of the cable forces during the construction process is similar.Through analysis,it is found that the method is different and the control parameters are different,but it can solve the problem.In essence,it is the search for the tension of each boom or the length of the stresslessness during the construction process.From the theoretical level,the cable force of the tie rod arch bridge of the Qinshui River Bridge is clarified and made better.Overall,the research results and reference values are very obvious.