Study On Mechanical Properties And Construction Optimization Of Arch Foot Of Unequal Span Tied Arch Bridge

Tied arch bridge is widely used in China because of its beautiful shape and good stress performance.In the tied arch bridge structure,the arch foot structure is complex and the stress is concentrated,which is one of the key parts to determine the span and bearing capacity of the whole bridge structure.In particular,the arch foot of unequal span tied arch bridge is often irregular in shape,which is subject to constraints and loads in multiple directions,resulting in unclear mechanical properties and stress state of the arch foot position.Therefore,the research on the mechanical properties and construction optimization of the arch foot position has important engineering significance.Supported by the key project "Sihe bridge-Research on key construction technology of unequal span tied arch bridge" of Zhongjiao Road Bridge Construction Co.,Ltd.,relying on the Sihe bridge project in the project,based on the local finite element analysis of the whole bridge structure and arch foot,combined with the field measurement,this paper systematically studies the mechanical properties and stress state of unequal span tied arch bridge and arch foot in each key stage of the whole bridge structure construction process.The main contents are as follows:(1)Based on the finite element software MIDAS civil,the finite element model of the whole bridge structure is established according to the structural characteristics of unequal span multi arch half through tied arch bridge;By comparing the measured and theoretical values of suspender cable force and vertical displacement of control section in the completion stage,the reliability of the finite element model of the whole bridge structure is verified.On this basis,the internal force and stress state of the whole bridge structure in each key stage in the construction process are analyzed,and the stress state of the arch foot in the construction process is preliminarily explored.(2)Based on the structural analysis of the whole bridge,and then based on the finite element software MIDAS FEA,the local solid model of the arch foot of unequal span tied arch bridge is established.According to the local boundary load conditions of the arch foot extracted from the structural analysis results of the whole bridge,the local stress state of the arch foot in each key construction stage is analyzed,and the stress distribution of the arch foot in each key stage is defined;The strength performance of the local constituent materials of the arch foot is tested,and the areas of stress concentration and poor stress in the local position of the arch foot are obtained.(3)By arranging strain sensors at the key positions of the arch foot and carrying out field tests,the stress changes of the arch foot during the construction of the whole bridge are tracked and monitored.By analyzing the measured stress change value,the construction stage which has a great influence on the local stress state of the arch foot is obtained;By comparing and analyzing the measured and theoretical values,the stress change mechanism of each part of the arch foot in the construction process is clarified;Based on the analysis results,the local optimization suggestions for the arch foot are put forward,and the construction of the arch foot position is optimized.The research results of this paper can provide some reference and suggestions for the design and construction of the arch foot position of unequal span tied arch bridge.