In many multistory buildings, basement levels are used as parking spaces. However, dimensions of reinforced concrete columns at these levels cause them to be unideal parking spaces. An alternative is to replace the RC columns in middle frames with steel columns that are not a part of seismic force resisting system and only support vertical loads, therefore have smaller sections. Using simply supported steel columns under the base level is beneficial not only because they have smaller cross-sections which lead to increasing the parking space but also these steel columns are easier to be replaced after any possible damages and can be considered as convenient alternatives compared to ordinary RC columns in construction. In this research, seismic performance of structures implementing the suggested alternative is evaluated using nonlinear static and dynamic analyses and compared to that of regular counterparts. Results show that these structures pass the acceptability tests proposed by FEMA P695 methodology. Moreover, seismic performance factors of these two structural systems have been calculated and proposed.

中文翻译：

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基准面下重力钢柱专用RC框架的抗震性能评估

在许多多层建筑物中，地下一层用作停车位。但是，钢筋混凝土柱在这些高度上的尺寸导致它们成为不理想的停车位。一种替代方法是用钢柱代替中间框架中的RC柱，这些钢柱不是抗震力系统的一部分，仅支撑垂直载荷，因此截面较小。在基础高度下使用简单支撑的钢柱不仅有好处，因为它们的横截面较小，从而导致增加了停车位，而且这些钢柱在遭受任何可能的损坏后更易于更换，并且与普通钢筋混凝土柱。在这项研究中 使用非线性静态和动态分析评估了采用建议替代方法的结构的抗震性能，并将其与常规对应结构进行了比较。结果表明，这些结构通过了FEMA P695方法论提出的可接受性测试。此外，已经计算并提出了这两个结构系统的抗震性能因子。