| With the rapid development of China’s infrastructure strength,China’s bridge construction level is also increasing.In the construction of tied arch bridge,the arch rib which is made of concrete-filled steel tube is common,but the arch rib which is made of the reinforced concrete is rare.The paper is based on a 108-meter prestreessed reinforced concrete tied arch bridge with lower bearing in Xingquan Railway,which is located in Fujian Province along the southeast coast.The tie beam is prestressed concrete and the arch rib is reinforced concrete.The cast-in-place model is adopted for both the tie beam and the arch rib,and the construction steps are complicated.The arch foot part is one-time pouring of mass concrete,the stress condition of the arch foot is complicated.The suspender is a flexible suspender,and the determination of bridge tension and construction tension is very important.In view of the above problems,through reading a large number of references and learning bridge model calculation,this paper mainly does the following work and research:(1)we take the finite element software which named Midas·Civil as the tool to create the bridge model,through the use of construction drawings to carry out a calculation analysis of comprehensive construction phase.The vertical displacement,bending moment value and stress value of arch rib and tie beam are extracted from each construction stage,and discussing the bridge performance which is in the operational status after completion of the bridge.And summarizing the conclusion in order to compare with actual construction,which hopes to play a guiding role in construction site.(2)Based on the construction drawing,the finite element model of the bridge is taken as reference,and the construction situation on is taken as the core.The site elevation and stress of the bridge are monitored at each construction stage,and the measured data are compared with the theoretical data which is calculated by the model.In order to find out the common and difference between them,we can summarize and refine the results to provide reference for the same type of bridge construction in the future.(3)Combining the construction drawings and the actual construction situation of the site,we can make use of the finite element software which named Midas·FEA to create a solid model of arch foot.Considering the vertical and transverse prestressed reinforcement,the stress variation of arch foot in different construction process and operation process is studied and analyzed.The unfavorable stress position of arch foot is marked.Where the arch foot has edges and corners,there is stress concentration in the intersection of straining beam and arch rib,so it is reasonable to adopt arc transition section at the intersection of arch rib and tie beam in the design.The overall mechanical performance of arch foot is good in the whole construction process.(4)By using finite element software Midas·Civil to calculate suspension force of this bridge,the ultimate cable force and construction cable force of the bridge are calculated respectively.The force of the suspender of the bridge is calculated by the method of elastic support continuous beam,unknown load coefficient and minimum bending energy,the minimum bending energy method is more suitable.The advantages and disadvantages of these three calculation methods are compared.We have final suspender force as the purpose,the construction period of the bridge is analyzed by the finite element software,and the construction cable force of the bridge is calculated by using the unclosed force method and the sequential iterative method respectively.The theoretical suspender force is compared with the field measured suspender force,the sequential iterative method is more suitable. |
