新型铁路高墩抗震性能与设计方法研究

High piers railway bridge have been widely applied in high-intensity earthquake areas in western China. The earthquake damage of high pier bridge has great influence on the political, economic and national defense, because high pier bridge cannot be replaced in the route. Based on the concept that main components have no earthquake damage, secondary components damage can be repaired or replaced, this project presents a new type of railway high pier structure, and studies its seismic behaviors and design methods. The new high pier is mainly composed of four columns (major component) and secondary members, the secondary members are the horizontal linkages between columns. The horizontal load bearing capacity, hysteretic characteristics, skeleton curves, energy dissipation capacity and failure mode are obtained based on the pseudo static model test. The numerical analysis model is established, and the analysis model is verified or corrected based on the shaking table model test results. Failure mechanism of the new high pier is revealed by numerical analysis and mechanism of high modes is clarified. The laws between the location, numbers and the key parameters of secondary components and the seismic responses are investigated. Measures for dealing with the higher mode effects are proposed. The quantitative indicators of seismic performance for secondary components are presented, based on the finite element analysis and component testing. Seismic design methods for railway high pier are established.

高墩在我国西部高烈度地震区的铁路中被大量采用。高墩桥梁在线路中具有不可替代性，其地震破坏对政治、经济及国防有重大影响。基于主要构件在地震中基本无损伤，次要构件损伤可修复或可更换理念，本课题提出一种新型铁路高墩结构，并研究其抗震性能及设计方法。新型高墩主要由四个墩柱（主要构件）及墩柱之间的纵、横向联系（次要构件）组成。通过拟静力模型试验，获得水平荷载作用下的极限承载能力、滞回特性、骨架曲线、耗能能力及破坏形态。建立数值分析模型，基于振动台模型试验结果进行模型的验证或修正。数值分析揭示新型高墩的地震破坏机理，阐明新型高墩中高阶振型作用机制，考查次要构件的数量、布置位置及关键技术参数变化对地震反应的影响规律，提出应对高阶振型效应的措施。采用构件试验与有限元分析相结合的方法提出次要构件的抗震性能量化指标，建立新型铁路高墩的抗震设计方法。

高墩桥梁在我国西部地区被广泛应用，高墩桥梁在线路中具有不可替代性，一旦地震中遭到破坏，短期内又很难修复，对社会的政治、经济、国防会产生重大影响，也会给抢险、救灾、疏散、供应等带来极大困难。随着抗震技术的不断进步、对抗震性能要求的不断提高，确保震后桥梁结构的完整性已是世界潮流所趋。基于主要构件在地震中基本无损伤，次要构件损伤可修复或可更换理念，本课题提出一种新型铁路高墩结构，并研究了其抗震性能及设计方法。新型高墩主要由四个墩柱（主要构件）及墩柱之间的纵、横向联系（次要构件）组成。正常使用及小地震作用下时使墩柱与联结构件形成一个整体，桥梁结构保持弹性，可按构格式桥墩进行设计。强震时墩柱保持基本弹性，次要构件按耗能构件设计。课题通过拟静力模型试验，获得了水平荷载作用下的极限承载能力、滞回特性、骨架曲线、耗能能力及破坏形态。开展了新型高墩振动台模型试验，记录了模型的墩顶及墩身的水平加速度、水平位移，横向联结系杆件的应变，墩柱中钢筋的应变等重要数据，可用于验证或修正新型高墩的力学分析模型。振动台试验结果表明：新型铁路高墩的抗震性能较好，可实现强震作用下墩柱处于基本弹性状态、桁架式横向联结系杆件屈服耗能，震后墩柱基本无损伤，损伤的次要构件可更换的抗震设防目标。建立了数值分析模型，数值分析揭示新型高墩的地震破坏机理，阐明新型高墩中高阶振型作用机制，提出应对高阶振型效应的措施，建立了新型铁路高墩的抗震设计方法。新型铁路高墩具有较好的抗震性能，有较好的应用前景。