Analysis Of Track Structure And Research On Temperature Span Of Continuous Rigid Frame Without Supports

Urban rail transit in China has been through a tremendous development. As one of the route laying mode, viaduct develops rapidly both in China and abroad, due to its low construction cost, high speed of construction, good adaptability of route line. During the construction of viaduct in China and abroad, bridges with standard span are mostly used, except for a few special control nodes. Traditionally, structures which common bridges with medium and small span use are simple supported beam and continuous beam. Continuous rigid frame is a pier-beam consolidation system developed from continuous beam, combining stressing features of continuous beam and t-shaped rigid frame. With good structural integrity, excellent seismic performance, great torsion potential, Continuous rigid frame has been wildly applied in China.This article focuses on an improved continuous rigid frame, pre-stressed concrete continuous rigid structure without supports. There are no supports in this bridge mode. Both side pier and central pier consolidate with girder, forming rigid frame. Transverse restraint of continuous rigid frame pier is weaker, and the bridge is easily twisted or displaced under the circumstance of unbalanced transverse load. When continuous rigid frame without supports is laid out continuously and compactly, unbalanced load generated by vehicle weight causes beam transverse in different directions, accelerating the horizontal distortion of rail and reducing security of train operation. Such results are caused by double-way line on the bridge and that adjacent steel units do not share piers.With the background of one-armed pier pre-stressed concrete continuous rigid structure without supports adopted by Guangzhou elevated metro line, this article stresses on the following research.1. This part introduced continuous rigid structure without supports, compared with traditional continuous rigid structure, continuous rigid structure without supports is easier to maintain, have lower maintenance cost and higher structure stress efficiency. Also, continuous rigid structure without supports shows better seismic performance and better appearance. The application situation of continuous rigid structure without supports is investigated, and the track structure rail, fasteners and construction under track of viaduct are systematically introduced.2. On the issue of the pier’s transverse rigidity impact on continuous welded rail on bridge, the evaluation standard of transverse rigidity in ballastless track structure of urban rail transit viaduct, suggesting transverse rigidity limited parameters of bridge system and fastener system are introduced.3. Using the2-4×40m one-armed pier pre-stressed concrete continuous rigid structure without supports adopted by Guangzhou elevated metro line as actual engineering background, the track structure parameter modeling’s influence on continuous welded rail on bridge is studied. Based on prior conclusion, the rule of pier’s transverse rigidity’s impact on continuous welded rail on bridge is studied, thus put forward the design requirement of pier and its logical transverse rigidity.4. Using the2-4x40m one-armed pier pre-stressed concrete continuous rigid structure without supports adopted by Guangzhou elevated metro line as actual engineering background, this part studied the varying pattern of pier’s top displacement, pier’s bottom bending movement and pier strength safety coefficient by changing continuous rigid frame span, and introduced the selection method of multi-span continuous rigid structure without supports’ temperature span and suggestion of span set.