Railway Pier, Large Span, Long Associated Cwr Girders Bridge Pier Longitudinal Horizontal Stiffness Optimization

The longitudinal linear stiffness in a horizontal direction of pier has become the main parameters in the design of railway bridge and jointless track, and both the addiction force and fast relative displacements of jointless track on bridge largely depend on it,so our country has provided clearly defined longitudinal linear stiffness in a horizontal direction for simple-supported beam bridge under 48m.Simple-supported beam bridge has been applied in pratice, but theoretical research relatively lags behind.Recently, researches on longitudinal linear stiffness of long, tall pier and long multi-spanned simple beam have rarely done, especially literatures of pier size optimization. Experiences are the main reference when deciding pier size and it always turn out to be conservative as no standard can be consulted in longitudinal linear stiffness design of simple beam pier above 48m. Taking economy and normal usage into consideration, it is important and realistic significant to strengthen design of longitudinal linear stiffness in a horizontal direction of simple beam pier.Based on the research results in the past, the author has completed the fellow works:(1)Analysis choices of various parameters of jointless track on bridge theoretically including the vertical and longitudinal stiffness on ballast layer, force coefficient and temperature coefficient and so on.(2)Based on the APDL language which is re-development by ANSYS and develop the finite element parameterized model. Calculate and analysis addition force of steel rail, and combine engineering practice with determining reasonable loading method of flexibility-addiction force, when calculating, by analysising influence line of rail buckle force.(3)In order to build optimization model, concret dosage is setted as the targe function, and allowable longitudinal addiction tension, compressive stress, fast relative displacements of track, horizontal displacement of pier, allowable tension and compressive stress of pier are setted as constraint condition.(4)Constitute the model with APDL language and optimize longitudinal linear stiffness of each pier of the whole bridge.(5)Compare the former result with the latter one, and work out the reasonable limit of longitudinal linear stiffness for pier of simple beam bridge pier at 64m.