A renewable energy storage system is being proposed through a multi-disciplinary research project. This system utilizes reinforced concrete pile foundations to store renewable energy generated from solar panels attached to building structures. The renewable energy can be stored in the form of compressed air inside the pile foundation with a hollowed section. The pile foundation should resist complex combined actions including structural loads, soil effects, and pressures induced from the compressed air, and thus it requires a careful analysis and design considerations to secure a sufficient structural safety. This paper presents analytical investigation results on the structural responses of the energy piles under these combined loadings. The pile foundations were designed based on the current design practices for various building geometries including the number of stories and column spacing. The magnitude of air pressure was determined from the thermodynamic cycles for the available renewable energy for storage considering building and pile foundation geometries. Finite element analyses were conducted using an elastic 3D model to determine critical tensile stresses of the pile foundation. These critical tensile stresses were used to identify required reinforcement in the pile section. On this basis, several nonlinear finite element analyses were then conducted using inelastic constitutive models of materials to investigate the crack patterns of the hollowed concrete section. Recommendations were finally presented for proper practical designs of the pile foundation serving as the renewable energy storage medium.

中文翻译：

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压缩空气压力作用下钢筋混凝土桩基础的结构响应用于可再生能源储存

正在通过多学科研究项目提出可再生能源存储系统。该系统利用钢筋混凝土桩基础储存太阳能电池板产生的可再生能源，这些能源连接到建筑结构上。可再生能源可以以压缩空气的形式储存在具有中空截面的桩基内。桩基应抵抗复杂的组合作用，包括结构载荷、土壤效应和压缩空气引起的压力，因此需要仔细分析和设计考虑，以确保足够的结构安全。本文介绍了在这些组合载荷下能量桩的结构响应的分析研究结果。桩基的设计基于当前各种建筑几何形状的设计实践，包括层数和柱间距。考虑到建筑物和桩基几何形状，空气压力的大小由可用于存储的可再生能源的热力学循环确定。使用弹性 3D 模型进行有限元分析，以确定桩基的临界拉伸应力。这些临界拉伸应力用于确定桩截面所需的钢筋。在此基础上，使用非弹性材料本构模型进行了多项非线性有限元分析，以研究空心混凝土截面的裂缝模式。