摘要
为减小地震作用下大跨度悬索桥主要构件的地震响应,降低结构地震破坏风险,在概念设计阶段确定大跨度悬索桥合理抗震结构体系,针对悬索桥特点提出了3种不同的中央扣形式和4种不同的梁端约束体系,结合某主跨640 m单跨钢桁梁悬索桥,使用有限元分析软件,通过非线性时程分析方法获得了不同约束体系下加劲梁端部、加劲梁跨中、塔顶等位置的位移响应和塔底以及关键构件的内力响应,在此基础上评估了不同约束体系对悬索桥抗震性能的影响。结果表明:设置中央扣可影响加劲梁纵漂特性,减小加劲梁纵向地震位移;柔性中央扣地震轴力超限会使中央扣失效,刚性中央扣会造成加劲梁局部应力过大;相比无中央扣的工况,在大跨度悬索桥跨中设置防屈曲支撑式中央扣可使梁端最大纵向地震位移降低35.29%,桥塔底部纵向弯矩和剪力分别降低9.47%和2.88%;防屈曲中央扣+梁端纵向黏滞阻尼器的组合布置使梁端最大纵向地震位移降低68.68%,桥塔底部纵向弯矩和剪力分别降低36.5%和23.6%;加劲梁端部与桥塔间设置横向防屈曲支撑使梁端部和跨中最大横向地震位移相比设置弹性拉索的工况分别降低73.9%和48.16%,桥塔底部横向弯矩相比设置弹性拉索的工况降低17.55%,横向剪力相比设置阻尼器的工况降低27.31%。研究结果可为同类型桥梁的抗震设计提供参考。
In order to reduce the seismic response of the main components of the long-span suspension bridge under the action of earthquake and reduce the seismic damage risk of the structure, the reasonable seismic structure system of the long-span suspension bridge was determined in the conceptual design stage, according to the characteristics of suspension bridges, 3 different forms of central buckles and 4 different restraint systems at the beam ends were proposed. For a single-span suspension bridge with a main span of 640 m, the finite element analysis software was used to obtain the displacement responses of the end of the stiffening beam, the mid-span and the top of the tower, and the internal force responses of the tower bottom and key components under different restraint systems. On this basis, the effects of different restraint systems on the seismic performance of suspension bridges were evaluated. The results show that setting the central buckle can affect the longitudinal drift characteristics of the stiffening beam, and reduce the longitudinal seismic displacement of the stiffening beam. The seismic axial force of the flexible central buckle exceeds the limit, which makes the central buckle invalid, and the rigid central buckle will cause the local stress of the stiffening beam to be too large. Compared with the case without the central buckle, the installation of the buckling restrained brace in the midspan of the long-span suspension bridge reduces the maximum longitudinal seismic displacement of the beam end by 35.29%, and the longitudinal bending moment and shear force at the bottom of the bridge tower by 9.47% and 2.88%, respectively. The combined arrangement of the buckling restrained brace and the longitudinal viscous damper at the beam end reduces the maximum longitudinal seismic displacement at the beam end by 68.68%, and the longitudinal bending moment and shear force at the bottom of the bridge tower by 36.5% and 23.6%, respectively. The transverse buckling restrained braces are arranged between the end of the stiffening beam and the bridge tower, which reduces the maximum transverse seismic displacement at the end of the beam and the mid-span by 73.9% and 48.16% respectively compared with the case where elastic cables are installed, the transverse bending moment at the bottom of the bridge tower is reduced by 17.55% compared with the case with elastic cables, and the transverse shear force is reduced by 27.31% compared with the case with dampers. The research results can provide reference for the seismic design of bridges of the same type. 5 tabs, 18 figs, 22 refs.
作者
周敉
徐梓涛
ZHOU Mi;XU Zi-tao(School of Highway,Chang’an University,Xi’an 710064,Shaanxi,China;Key Laboratory for Old Bridge Detection and Reinforcement Technology of the Ministry of Transportation,Chang’an University,Xi’an 710064,Shaanxi,China)
出处
《长安大学学报（自然科学版）》
CAS
CSCD
北大核心
2022年第6期90-100,共11页
Journal of Chang’an University(Natural Science Edition)
基金
国家重点研发计划项目(2021YFB1600300)
国家自然科学基金项目(51978062)
陕西省自然科学基础研究计划项目(2021JLM-47)
中央高校基本科研业务费专项资金项目(300102212209)。
关键词
桥梁工程
约束体系
非线性时程分析
悬索桥
抗震设计
bridge engineering
constraint system
nonlinear time history analysis
suspension bridge
aseismic design
