Investigating the nonlinear dynamic response of reinforced concrete (RC) structures is of significant importance in understanding the expected behavior of these structures under dynamic loading. This becomes more crucial during the design of new or the assessment of the existing RC structures that are located in seismically active areas. The numerical simulation of this problem through the use of detailed 3D modeling is still a subject that has not been investigated thoroughly due to the significant challenges related to numerical instabilities and excessive computational demand, especially when the soil–structure interaction (SSI) phenomenon is accounted for. This study aims at presenting a nonlinear simulation tool to investigate this numerically cumbersome problem in order to provide further inside into the SSI effect on RC structures under nonlinear dynamic loading conditions. A detailed 3D numerical model of full-scale RC structures considering the SSI effect through modeling the nonlinear frame and soil domain is performed and discussed herein. The constructed models are subjected to dynamic loading conditions and an elaborate investigation is presented considering different type of structures, material properties of soil domains and depths. The RC structures and the soil domains are modeled through 8-noded hexahedral isoparametric elements, where the steel bar reinforcement of concrete is modeled as embedded beam and truss finite elements. The Ramberg–Osgood constitutive law was used for modeling the soil domain. It was shown that the SSI effect can significantly increase the flexibility of the system, altering the nonlinear dynamic response of the RC frames causing local damages that are not observed when the fixed-base model is analyzed. Furthermore, it was found that the structures founded on soft soil developed larger base-shear compared to the fixed-base model which is attributed to resonance phenomena connected to the SSI effect and the imposed accelerograms.

中文翻译：

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土-结构相互作用对钢筋混凝土结构非线性动力响应的影响

研究钢筋混凝土 (RC) 结构的非线性动态响应对于了解这些结构在动态载荷下的预期行为具有重要意义。这在设计新的或评估位于地震活跃地区的现有 RC 结构时变得更加重要。由于与数值不稳定性和过多的计算需求相关的重大挑战，特别是考虑到土壤-结构相互作用 (SSI) 现象时，通过使用详细的 3D 建模对该问题进行数值模拟仍然是一个尚未彻底研究的主题为了。本研究旨在提供一种非线性仿真工具来研究这个数值繁琐的问题，以便进一步深入了解非线性动态加载条件下 RC 结构的 SSI 效应。本文通过对非线性框架和土壤域建模来执行和讨论考虑 SSI 效应的全尺寸 RC 结构的详细 3D 数值模型。构建的模型受到动态加载条件的影响，并考虑到不同类型的结构、土壤域的材料特性和深度，进行了详细的研究。RC 结构和土域通过 8 节点六面体等参数单元进行建模，其中混凝土钢筋建模为嵌入梁和桁架有限元。Ramberg-Osgood 本构法用于模拟土壤域。结果表明，SSI 效应可以显着提高系统的灵活性，改变 RC 框架的非线性动态响应，从而导致在分析固定基础模型时未观察到的局部损坏。此外，发现与固定基础模型相比，建立在软土上的结构产生了更大的基础剪切，这归因于与 SSI 效应和施加的加速度图相关的共振现象。