Research On Overalland Detailed Arch Foot's Stress Analysis Of Continuous Beam-arch Bridge In Large Span

As a new composite structure applied to railway,especially high-speed in railway,the continuous beam-arch bridge overcomes the shortcomings of the arch bridge's high requirement for foundation and high material index of continuous beam.It has the advantages of large structural stiffness,good dynamic stability,large span,beautiful shape and convenient construction.There are strategies such as acceleration of the railway's speeded up,continuous construction of passenger dedicated line,"One Belt One Road " and " China high-speed rail going out" continue to advance,the application of this type of bridge will be more and more extensive,so it is very necessary to carry out a comprehensive study of this type of bridge type.In this thesis,the development and history of continuous beam-arch bridge are reviewed,and its stress characteristics are summarized.Taking the continuous beam-arch bridge with a span combination of(78+168+78)m in Chengdu to Chongqing passenger dedicated line as the research background,to calculation and analyze the static and dynamic effects of the continuous beam-arch bridge in the construction and operation stages of the large span in railway and discus the stress state and optimization of the connection between the main beam and the arch rib.Firstly,the finite element software MIDAS/CIVIL2015 is used to establish the finite element model of the full bridge space based on the beam element,so as to calculate and analyze the force variation of bridge structure in each construction stage and the change law of the section of the cantilever root section with the advancement of construction stage.And the combined effect of structure under the action of dead load,train live load,temperature load,braking force,wind load and derailment load under various load conditions are studied in detail.Secondly,analyze the dynamic characteristics of the bridge state,and the self vibration period and vibration mode of the bridge are obtained,then use response spectrum method and time-history method to calculate the seismic response of the structure under different working conditions.Afterwards compare and analyze the results of response spectrum method and time history method for typical structural parts under seismic load excitation.Finally,use the large general finite element software ANSYS to establish a detailed finite element model of the joint of the joint between arch and beam,then analyze stress distribution in various parts under adverse load combination.Meanwhile,summarize the stress distribution rule of the joint between arch and beam,in order to explore the design and optimizationproposal for connection between arch and main beam in the same type of bridge.In this thesis,the static and dynamic performance of continuous beam-arch bridge in a large span has been studied.It is expected to provide a reference for the design and research of the same kind of bridge.