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首页> 外文学位 >Seismic performance of shallow-founded structures on liquefiable ground: An experimental and numerical study.
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Seismic performance of shallow-founded structures on liquefiable ground: An experimental and numerical study.

机译：可液化地面上浅层结构的抗震性能：一项实验和数值研究。

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摘要

Recent earthquakes have shown that even buildings designed according to local seismic regulations may suffer damage due to liquefaction. This is because the mechanisms that lead to a loss of building serviceability due to liquefaction are not well understood and considered in the design of structures. The current state-of-practice for estimating liquefaction-induced building settlement is primarily based on procedures that assume free-field conditions and are known to be unreliable, because they do not account for changes in stress distribution, flow patterns, and soil-foundation-structure interaction.;In this research, results from centrifuge experiments are used to: 1) gain insight into the underlying mechanisms of deformation near structures on softened ground; and 2) validate and evaluate the capabilities and shortcoming of an advanced numerical tool, which are then employed in a parametric study.;Solid-fluid, fully-coupled, nonlinear, effective stress, 3D, finite element analyses are performed in the OpenSees platform. The key Engineering Demand Parameters (EDPs) of interest that quantify the performance of the soil-foundation-structure system (e.g., excess pore pressures, accelerations, and settlements, foundation tilt, and transient inter-story drift) were compared numerically and experimentally. For the cases considered, numerical predictions compared fairly well with experimental results, with the exception of free-field settlement and permanent foundation tilt.;A numerical parametric study, validated against experiments was then performed, in which different soil, structural, and ground motion Input Parameters (IPs) were systematically varied to investigate the influence and relative importance of different IPs, and to search for and identify optimum Intensity Measures (IMs) that minimized the variability and uncertainty in estimating different EDPs. The extent of excess pore pressure generation (EDP = r u,peak) in the free-field and near the structure was significantly influenced by relative density and thickness of the liquefiable layer. These factors along with the foundation contact pressure and area were shown to significantly influence building settlements. Spectral acceleration at the initial period of the site as well as Arias Intensity were identified as optimum IMs for predicting ru,peak and foundation settlement, respectively. Additional simulations validated against case histories will be necessary to develop a probabilistic method for predicting the performance of structures on softened ground.
机译：最近的地震表明，即使按照当地地震法规设计的建筑物也可能由于液化而遭受损坏。这是因为在结构设计中没有充分理解和考虑由于液化导致建筑物使用性丧失的机理。当前估算液化引起的建筑物沉降的实践状态主要是基于假定自由场条件且已知不可靠的程序，因为它们未考虑应力分布，流动模式和土壤基础的变化-结构相互作用。;在这项研究中，离心试验的结果用于：1）洞察软化地面上结构附近变形的潜在机理； 2）验证和评估先进的数值工具的功能和缺点，然后将其用于参数研究中；在OpenSees平台中进行固液，全耦合，非线性，有效应力，3D和有限元分析。在数值上和实验上比较了感兴趣的关键工程需求参数（EDP），这些参数量化了土壤-基础-结构系统的性能（例如，多余的孔隙压力，加速度和沉降，地基倾角和过渡层间漂移）。对于所考虑的情况，除了自由场沉降和永久性地基倾斜之外，数值预测与实验结果相当吻合；然后进行了数值实验，并针对不同的土壤，结构和地震动对实验进行了验证系统地改变了输入参数（IP），以调查不同IP的影响和相对重要性，并搜索和确定最佳强度测度（IM），该测度可最大程度地减少估计不同EDP时的可变性和不确定性。自由场和结构附近的过大孔隙压力产生的程度（EDP = r u，peak）受到可液化层的相对密度和厚度的显着影响。这些因素以及地基接触压力和面积显示出对建筑物沉降的显着影响。现场初始阶段的光谱加速度以及Arias强度被确定为分别预测钌，峰和基础沉降的最佳IM。针对案例历史进行验证的其他模拟对于开发一种概率方法来预测软土地基上结构的性能将是必要的。

著录项

  • 作者

    Karimi, Zana.;

  • 作者单位

    University of Colorado at Boulder.;

  • 授予单位 University of Colorado at Boulder.;
  • 学科 Civil engineering.;Architectural engineering.
  • 学位 Ph.D.
  • 年度 2016
  • 页码 203 p.
  • 总页数 203
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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