【摘要】 研究目的:我国高速铁路桥梁广泛采用少筋混凝土重力式桥墩,但现行震规对这种结构在多遇地震作用下如何验算缺少相应的研究。本文以32 m简支梁桥圆端型桥墩为研究对象,针对此问题讨论如何利用偏心及应力指标进行验算,讨论少量纵向主筋对提高重力式桥墩承载能力及稳定性的作用。研究结论:(1)对少筋混凝土重力式桥墩,可采用容许应力法或偏心进行验算;(2)采用容许应力法验算可保证墩身的截面强度及整体倾覆稳定性;(3)采用偏心验算少筋混凝土桥墩时,容许偏心值随配筋率不同而不同;(4)对于配筋率为0.1%、0.2%、0.3%及0.4%的圆端型桥墩,容许偏心可分别放宽至0.90S、1.0S、1.1S、1.2S;(5)本研究结果可为多遇地震下少筋混凝土重力式桥墩的验算方法提供理论依据。更多还原

【Abstract】 Research purposes:Concrete gravity type piers with low longitudinal reinforcement ratio are extensively used in high- speed railway in China.However,how to check such structures is not specified in current technical codes.With the round end pier of 32 m simply- supported girder bridge as research subject,how to check the structures by eccentricity and stress indexes is studied.The effect of longitudinal reinforcement on improving the bearing capacity and stability of the pier is discussed.Research conclusions:(1) The allowable stress approach or section eccentricity could be used to check concrete gravity type piers with low longitudinal reinforcement ratio.Strength and stability of the pier can be ensured when the allowable stress approach is used.(2) When section eccentricity is used as checking index,the restriction values may vary from longitudinal reinforcement ratio.(3) For the round end piers with longitudinal reinforcement ratio of 0.1%,0.2%,0.3%and 0.4%,permissible eccentricity can be magnified to corresponding values for 0.90 S,1.0S,1.1S,1.2S.(4) The results can provide a theoretical basis for calculation method of the concrete gravity type pier with low longitudinal reinforcement ratio under low- level earthquakes.更多还原