Study On Mechanical Performance Of Continuous Rigid Frame Bridge Of Single Track Railway

The rigid frame bridge is widely used in highway and railway in China and abroad.Because of structural rigidity and stability,the span of the rigid frame bridge of single-line railway is usually used in less than 168 m,It is rarely to see for the main span of 192 m with different heights of piers.Therefore,it is necessary to study the mechanical properties of the rigid frame bridge with high and low piers in the single-line railway.1.The control factors of the stiffness design of high and low piers were proposed.The influence of various factors on stiffness is analyzed.The design parameters and dimension of the main girder and pier are proposed.Major conclusions: The size of pier is the main control factor of stiffness,and its effect on stiffness is much greater than that of the main beam;Amount of masonry of the pier concentrated in the bottom of the pier(by lateral transverse slope rate),which can effectively improve the structure stiffness(especially the transverse stiffness),lower center of gravity structure,improve the comfortableness of traveling.2.The whole bridge finite element model is established,the main girder stiffness,strength and durability,and transverse mechanical properties is analysed,the strength and stability of the pier and foundation is studied.Major conclusions: the main beam vertical and lateral stiffness are excellent with the proposed value of the structure design dimension.The structure and strength of the upper and lower parts meet the requirements,and have certain safety reserves.3.Based on the structural dynamic numerical model,the analysis is based on the dynamic characteristics of the engineering.The seismic performance is analyzed by using three levels anti-seismic targets.Major conclusions: In the frequent earthquakes,the main bridge pier and the pile foundation are elastic;In the rare earthquake,the main pier enters elastic-plastic state,ductility design meets the specification requirement,The structure with damage but not whole collapse.The research results of this thesis have been applied in the main bridge of WuJiang bridge successfully and it provide a design reference of similar bridge.