关键词: 简支梁桥, 无砟轨道, 无缝线路, 梁轨相互作用, 钢轨附加应力, 跨数, 墩顶刚度 

Abstract: Based on the principle of bridgetrack interaction，the formula of multispan simply supported bridgetrack interaction considering nonlinear resistance was deduced and compared with the finite element ( FE) method to research the continuously welded rail ( CWR) stress of different ballastless tracks on multispan simply supported girder bridges． Different ballastless track models on simply supported girder bridges with standard span of 32m were established，and the rail additional stress distribution and its stable maximum value were analyzed considering the coupled effect of measured temperature and brake flexural force． Meanwhile， the influences of structural parameters such as span number of simply supported bridges，pier top stiffness and fastener resistance on the stress of CWR were also discussed． The results show that for girder bridges with standard span of 32m， the rail maximum additional stress tends to remain unchanged with the increase of the number of the bridge span，and the unchanged value is less than the norm limit; for the simply supported bridge with ballastless track，its span number is not limited by the rail additional stress; for the unitslab and double-block ballastless track， the change of pier stiffness has little effect on the rail additional stress when the pier top stiffness is greater than 2000kN/cm． Small resistance fasteners

Key words: simply supported girder bridge, ballastless track, continuously welded rail, bridgetrack interaction, rail additional stress, span number, pier top stiffness．