SGER: Sensitivity Analysis of Concrete Gravity Dams Subjected to Non-Uniform Seismic Excitations

文摘：混凝土重力坝的地震反应评估需要特别关注这些结构的独特特点：(1)它们是位于复杂场地的长结构，因此，地震动场的空间变异性起着重要作用；(2)坝-库基础(岩石)相互作用是结构反应的一个重要组成部分；(3)由于混凝土中存在相当大的断裂过程区，特别是在这些结构的施工中使用的大骨料混凝土，其非线性本构模型尚未完全量化。虽然人们已经清楚地认识到地震动场的空间变异性在大坝地震反应分析中不能被忽略，但对混凝土重力坝的这种影响还没有进行评估。这一探索性的SGER建议首次解决了将地震地面运动的空间变异性纳入混凝土重力坝响应评估的问题，并对空间变异性对这些巨型结构响应的影响进行了敏感性分析。它提出了精确建模和计算之间的折衷，初步尝试评估混凝土重力坝在大范围非均匀地震激励下的反应，并量化空间变异性的影响。建模近似将考虑在更简单的地形环境中的更复杂的结构或在更复杂的地形环境中的更简单的结构。地震地面运动将是深度记录的数据(代表8.0级以下地震的记录)，将作为“参考”地面运动，由此产生空间可变的地面运动。这项工作的结果可以作为未来研究的种子，用于选择关键的非均匀输入运动特征，用于复杂环境下混凝土重力坝详细模型的响应评估。

Abstract:The seismic response evaluation of concrete gravity dams requires special attention due to the unique characteristics of these massive structures: (i) they are long structures located at complex sites, and hence, the spatial variability of seismic ground motions plays a significant role; (ii) dam-reservoir foundation (rock) interaction is an important component of the structural response; and (iii) due to the sizable fracture process zone in concrete, and, especially, the large aggregate concrete used in the construction of these structures, their non-linear constitutive modeling is not yet fully quantified. Even though it has been clearly recognized that the spatial variation of seismic ground motions cannot be neglected in the seismic response analysis of dams, no evaluation of this effect on concrete gravity dams has been conducted. This exploratory SGER proposal addresses, for the first time, the issue of incorporating the spatial variation of seismic ground motions in the response evaluation of concrete gravity dams, and conducting sensitivity analyses of the effect of spatial variability on the response of these massive structures. It proposes a compromise between accurate modeling and computational effort in an initial attempt to evaluate the response of concrete gravity dams subjected to a wide range of non-uniform seismic excitations and to quantify the effect of spatial variability. The modeling approximations will consider either a more complex structure in a simpler topographic setting or a simpler structure in a more complex topographic setting. The seismic ground motions will be recorded data at depth (representative of recordings of earthquakes with magnitudes up to 8.0) that will serve as the "reference" ground motions, from which spatially variable ones will be generated. The results of this effort can then be used as "seed" in future studies for the selection of critical non-uniform input motion features for the response evaluation of detailed models of concrete gravity dams in complex settings.