摘要
为了解决斜拉桥低矮边墩的横向抗震难题,提出了采用X形钢挡块+活动球钢支座的准隔震约束体系。首先采用实体有限元对X形钢挡块的力学性能进行了仿真分析,并将试验和解析结果进行对比验证,为准隔震约束体系的参数优化奠定了基础;然后根据推倒分析提出了低矮边墩的位移损伤指标;最后基于非线性时程分析,对比研究了固定、活动和准隔震3种体系对斜拉桥横向抗震性能的影响,并对X形钢挡块进行了参数优化。研究表明:低矮排架墩的位移延性能力介于1.0~2.0之间,宜作为弹性构件进行抗震设计;横向固定体系会导致低矮边墩出现3.0以上的位移延性需求,横向活动体系则会导致支座因位移超限而损坏,而准隔震约束体系可将边墩位移延性需求降至1.0以下,将支座位移控制在安全范围内,还可大幅降低主塔内力响应(降幅超过38%)。为了使准隔震约束体系发挥最佳抗震效果,X形钢挡块的强度和刚度应在合理范围内取值,文中桥例的X形钢挡块建议按8片钢板来进行设计。
In order to solve the problem of lateral seismic design of cable-stayed bridge with short side piers,a quasi-isolation restraint system was proposed by application of X-shaped steel retainers and movable spherical steel bearings.Firstly,the mechanical properties of the X-shaped steel retainers were simulated by using the solid finite element method,and validated against the experimental and analytical results,which facilitated the subsequent parameter optimization for the quasi-isolation restraint system.Then,the displacement damage indexes were developed for the short side piers based on pushover analyses.Finally,the nonlinear time history analyses were conducted to compare the effects of three transverse restraint systems,including a fixed system,a free system and a quasi-isolated system,on the lateral seismic performance of cable-stayed bridge.And the parameters were optimized for the X-shaped steel retainers.The results showed that the displacement ductility capacities of short bent piers range between 1.0~2.0,and therefore should be designed as elastic members.The fixed system leads to displacement ductility demands of more than 3.0 on the short side piers,while the free system leads to damage of bearings due to excessive displacement excursions.The quasi-isolation system can reduce the displacement ductility demands of side piers to less than 1.0,and control the bearing displacements within the safe range.Moreover,the quasi-isolation system is able to reduce significantly the internal force responses of the pylon by more than 38%.To bring out the best anti-seismic efficacy of the quasi-isolation system,the X-shaped steel retainers were designed within a reasonable range of yielding capacities and initial stiffnesses.It is suggested that the X-shaped steel retainers of the illustrative bridge studied in this paper should be designed using 8 X-shaped steel plates.
作者
徐略勤
赵洋
徐意宏
XU Lueqin;ZHAO Yang;XU Yihong(School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University,Chongqing 400074,China)
出处
《自然灾害学报》
CSCD
北大核心
2021年第6期97-107,共11页
Journal of Natural Disasters
基金
国家自然科学基金项目(51978113)
重庆市自然科学基金项目(CSTC2019JCYJ-MSXMX0691)。
关键词
斜拉桥
准隔震约束体系
低矮边墩
X形钢挡块
参数优化
cable-stayed bridge
quasi-isolation restraint system
short side piers
X-shaped steel retainers
parameter optimization
