高烈度不对称深切峡谷区铁路桥梁桥式方案研究  

Research on Types of Railway Bridges in High-Intensity Seismic Zones with Asymmetric Deep-Cut Valleys

作　　者：陈银灯 CHEN Yindeng(China Railway First Survey and Design Institute Group Co.,Ltd.,Xi'an 710043,China)

机构地区：[1]中铁第一勘察设计院集团有限公司,西安710043

出　　处：《铁道标准设计》2024年第10期83-90,共8页Railway Standard Design

基　　金：中铁第一勘察设计院集团有限公司科研课题(院科20-12)。

摘　　要：某铁路桥梁位于近断层高烈度地震区、不对称深切峡谷,为确定该铁路桥梁桥式方案,综合考虑气候条件、地形地貌、地质条件等因素提出(95+160+95+59)m预应力混凝土连续刚构、(60+200+106+50)m部分斜拉桥和(253+145)m连续钢桁柔性拱3个桥式方案,并详细介绍了各方案桥梁结构尺寸和施工方案。采用BSAS和Midas Civil有限元软件建立桥梁结构分析模型,对主梁、桥塔、桥墩、桩基、动力特性等进行计算分析,并从结构刚度、施工难度、施工周期、抗震性能、维修养护、工程造价等方面对3个方案进行比较。结果表明:(1)静活载作用下,连续刚构竖向位移为38 mm,挠跨比为1/4210;部分斜拉桥竖向位移为135.4 mm,挠跨比为1/1477;连续钢桁柔性拱竖向位移为78 mm,挠跨比为1/3231。(2)连续刚构桥一阶周期2.02 s,部分斜拉桥一阶周期2.4 s,钢桁柔性拱一阶周期2.58 s。(3)3个桥式方案均能满足规范要求,方案均安全可行,但连续刚构桥造价远低于部分斜拉桥和连续钢桁柔性拱。(4)预应力混凝土连续刚构桥刚度大、施工技术成熟、抗震效果良好、工程造价低、后期维修养护工作量小,方案最优。A railway bridge is located in a high-intensity seismic zone near a fault,with asymmetric deep-cut valleys.To determine the optimal bridge design,three types of bridge structures were proposed,taking into account climatic,topographical,geological conditions,and other relevant factors.The proposed schemes included a(95+160+95+59)m prestressed concrete continuous rigid-frame bridge,a(60+200+106+50)m partial cable-stayed bridge and a(253+145)m continuous steel truss flexible arch.Each schemes structural dimensions and construction methods were introduced in detail.Finite element analysis models for the bridges were established using BSAS and Midas Civil software,and analyses were conducted on the main beams,pylons,piers,pile foundations and dynamic characteristics.Comparisons of the three schemes were performed based on structural stiffness,construction difficulty,construction period,seismic performance,maintenance requirements and engineering cost.The results showed that:(1)Under static load,the continuous rigid-frame bridge exhibited a vertical displacement of 38 mm,with a span-to-deflection ratio of 1/4210;the partial cable-stayed bridge had a vertical displacement of 135.4 mm,with a span-to-deflection ratio of 1/1477;and the continuous steel truss flexible arch showed a vertical displacement of 78 mm,with a span-to-deflection ratio of 1/3231.(2)The first-order period of the continuous rigid-frame bridge was 2.02 s;the partial cable-stayed bridge was 2.4 s;and the steel truss flexible arch was 2.58 s.(3)All three bridge schemes met the design specifications and were proven to be safe and feasible,but the continuous rigid-frame bridge was significantly more cost-effective than the other two options.(4)Prestressed concrete continuous rigid-frame bridge,with its large stiffness,mature construction technology,superior seismic performance,low engineering cost and minimal maintenance requirements,was considered the optimal scheme.

关 键 词：铁路桥梁 桥式方案 高烈度 深切峡谷 连续刚构桥 部分斜拉桥 连续钢桁柔性拱 

分 类 号：U24[交通运输工程—道路与铁道工程] U448.13[建筑科学—桥梁与隧道工程] U442.5