Optimal intensity measures for probabilistic seismic demand modeling of extended pile-shaft-supported bridges in liquefied and laterally spreading ground
Optimal intensity measures for probabilistic seismic demand modeling of extended pile-shaft-supported bridges in liquefied and laterally spreading ground
复制标题
DOI：
10.1007/s10518-017-0199-2
复制
发表时间：
2017
影响因子：
4.6
通讯作者：
Xiaowei Wang;A. Shafieezadeh;A. Ye
中科院分区：
文献类型：
--
作者：
Xiaowei Wang;A. Shafieezadeh;A. Ye
地震烈度测度在概率地震需求建模中起着关键作用。许多研究探讨了适当的IM结构不考虑土壤液化的潜力。特别是，在液化和横向扩展的地面桥梁的概率地震需求建模的最佳IM没有全面研究。本文采用桥-土-地基耦合模型，对文献中的26种最优结构模型进行了深入的研究。模型中考虑了桥梁结构和岩土材料特性以及几何参数的不确定性，以产生全面的情景。针对不同的需求参数，评估了效率、实用性、熟练性、充分性和危险可计算性等指标。此外，信息理论为基础的方法，采用评估的相对充分性研究的IM。结果表明，速度相关的IM相比，加速度，位移和时间相关的优越性。其中，Housner谱强度（HI）、2.0 s谱加速度（Sa-20）、峰值地面速度（PGV）、累积绝对速度（CAV）及其修正形式（CAV 5）是最优的IM。相反，阿里亚斯强度（Ia）和震动强度率（SIR），这是液化评价或相关的结构需求评估中经常使用的措施，表现出非常低的相关性与需求参数。此外，几何参数对最优积分方程的选择没有明显的影响。此外，信息论为基础的充分性排名的IM显示了相同的结果与相关性措施的基础上的决定系数（R2）。这意味着R2可以用来初步评估IM的相对充分性。
Seismic intensity measures (IMs) perform a pivotal role in probabilistic seismic demand modeling. Many studies investigated appropriate IMs for structures without considering soil liquefaction potential. In particular, optimal IMs for probabilistic seismic demand modeling of bridges in liquefied and laterally spreading ground are not comprehensively studied. In this paper, a coupled-bridge-soil-foundation model is adopted to perform an in-depth investigation of optimal IMs among 26 IMs found in the literature. Uncertainties in structural and geotechnical material properties and geometric parameters of bridges are considered in the model to produce comprehensive scenarios. Metrics such as efficiency, practicality, proficiency, sufficiency and hazard computability are assessed for different demand parameters. Moreover, an information theory based approach is adopted to evaluate the relative sufficiency among the studied IMs. Results indicate the superiority of velocity-related IMs compared to acceleration, displacement and time-related ones. In particular, Housner spectrum intensity (HI), spectral acceleration at 2.0 s (Sa-20), peak ground velocity (PGV), cumulative absolute velocity (CAV) and its modified version (CAV5) are the optimal IMs. Conversely, Arias intensity (Ia) and shaking intensity rate (SIR) which are measures often used in liquefaction evaluation or related structural demand assessment demonstrate very low correlations with the demand parameters. Besides, the geometric parameters do not evidently affect the choice of optimal IMs. In addition, the information theory based sufficiency ranking of IMs shows an identical result to that with the correlation measure based on coefficient of determination (R2). This means thatR2can be used to preliminarily assess the relative sufficiency of IMs.