砂土中桥梁高桩承台基础的抗震延性能力参数分析  

Parametric study on seismic ductility capacity of bridge elevated pile-cap foundation in sand

作　　者：王晓伟[1] Guillermo Blanco 叶爱君[1] 赫中营 Wang Xiaowei;Guillermo Blanco;Ye Aijun;He Zhongying(State Key Laboratory of Disaster Reduction in Civil Engineering, Shanghai 200092, China;MC2 Structure Design Company, Madrid 28016, Spain;Henan University, Kaifeng 475001, China)

机构地区：[1]同济大学土木工程防灾国家重点实验室,上海200092 [2]西班牙马德里MC2结构设计公司,西班牙马德里28016 [3]河南大学,河南开封475001

出　　处：《土木工程学报》2018年第5期112-121,共10页China Civil Engineering Journal

基　　金：土木工程防灾国家重点实验室(SLDRCE15-B-05)、973计划(2013CB036302)

摘　　要：尽管现行的各国抗震规范对桩基础优先按照能力保护构件进行设计,但以往震害和相关分析表明,桩基础进入非线性对于桥梁的抗震性能并非一定不利。基于此出发点,本文采用Pushover方法对2×3高桩承台基础的延性能力进行了参数分析,探究其延性抗震的潜力。数值模型通过某高桩承台基础的拟静力试验进行了验证。参数分析考虑了桩基础、上部结构和土体三方面参数变化的影响,包括桩径、配筋率、配箍率、恒载轴压比、承台底附加弯矩、自由段长度和土体相对密实度。提出了基于不同性能状态的高桩承台基础延性能力指标:"易修位移延性系数"和"极限位移延性系数",揭示了指标随各参数的变化规律;结果表明,易修、极限位移延性系数基本符合对数正态分布,中位值分别为2.66、3.82,延性能力可观;另外,建立了位移延性系数和截面曲率延性系数的定量关系。Although current seismic design codes in different countries give priority to obey the philosophy of capacity design for piles, limited structural yielding of piles may not be always detrimental. In this regard, the ductile behavior of 2×3 Elevated Pile-cap Foundations （EPFs） is investigated using Pushover analysis to explore their potentials for seismic ductility design. The numerical model is calibrated by a quasi-static test. Parametric studies are performed considering the structural and soil properties, including pile diameter, longitudinal reinforcing ratio, transverse reinforcing ratio, initial axial compressive ratio, superstructure inertia induced bending moment, aboveground height and soil relative density. Ductility indices called Reparable Displacement Ductility Factor （RDDF） and Ultimate Displacement Ductility Factor （UDDF） are proposed and the effects of different variables on the ductile properties of EPFs are revealed. Median values for the RDDF and UDDF （2.66 and 3.82, respectively） are derived and the quantitative relationships between the RDDF, UDDF and curvature ductility factor are established.

关 键 词：高桩承台基础 有限元方法 拟静力试验 PUSHOVER 延性能力 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]