Finite Element Analysis And Construction Monitoring Of Railway Concrete-filled Steel Tubular Tied Arch Bridge

This paper takes the newly-built Heshun-Xingtai Railway Xucun tied arch bridge as the engineering background,and systematically analyzes the mechanical performance of the main components in the construction process of this kind of bridge.The main contents of the analysis are as follows:(1)The overall model of the tied arch bridge is established by Midas Civil software,and the force analysis performance of the bridge is analyzed in detail by the method of formal analysis;(2)The influence of stress on the arch rib is analyzed by changing the pouring sequence of the arch rib concrete during construction and adopting different shrinkage and creep modes,and focused analysis of the bridged state determined by different methods;(3)The finite element model of the abutment entity was established by Midas FEA software,and the stress distribution of the abutment during the construction and operation phases was studied;(4)By testing the stress and deformation of the main beam and arch rib at each construction stage,as well as the internal force of the boom,and comparing it with the finite element model to guide the construction of the bridge.The main results are as follows:(1)When constructing the ribbed concrete,the construction method of firstly symmetrically pouring the upper pipe concrete and then symmetrically pouring the lower pipe concrete causes the force and deformation of the arch rib to be more stable.(2)For the four different shrinkage and creep modes in this study,the stress of the arch ribs is the largest according to JTG D62-2004,and the results are similar according to CEB-FIP(1990)and CEB-FIP(2010).The revised JTG D62-2004 calculates the smallest results.According to relevant engineering experience and related literature,CEB-FIP(2010)is recommended to calculate the shrinkage and creep of concrete filled steel tube.(3)Through the study of the bridging state of the Xucun tied arch bridge,it can be seen that the optimization result obtained by " Zero-displacement method" is the worst.The arch rib bending moment and the bridge boom force calculated by “Rigid-suspender method”,“Moment minimum method” and “Minimum bending strain energy method” are similar,but the bending moment calculated by the minimum bending strain energy method is the most uniform.(4)During the construction phase and operation phase,the abutment is mainly subjected to compression.Different stress concentrations will occur at the bearing position and the sudden change of the main beam stiffness.The construction quality of the area should be paid attention to during construction to ensure the dispersion of stress.(5)During the construction process,the line shape,stress and boom force are monitored in real time.The monitoring results show that the stress and deformation of each part in the construction process are in compliance with relevant specifications,and the bridge boom force is also reasonable.