Seismic Behavior of Unanchored Liquid Storage Tanks

近二十年来，地基储液罐在水平和垂直荷载作用下的抗震性能受到了广泛的关注。然而，这些研究大多只涉及锚定储罐的行为。很少有人尝试分析无锚储罐的复杂行为，所寻求的模型要么太简单而无法捕捉这种结构的基本反应，要么太复杂而无法同时模拟许多特征。一般认为，在整个系统的分析中，底板的行为是一个主导因素。此外，根据以往的实验测试，液体晃动对非锚固罐的响应比锚固罐的响应有更明显的影响。本研究将对无锚储罐的地震反应进行综合分析。本研究由理论研究和实验研究两部分组成，分为三个主要阶段：考虑罐底与基础的非线性接触、大变形、非弹性响应等因素，对罐底在升力作用下的非线性静动力响应进行了分析。它与下伏土壤的相互作用及其在冲击下的行为；2. 分析了液体的非线性响应，并计算了相应的动水压力；和3。中强地震作用下筒体、液体和底板的耦合响应分析。该研究将提供理论结果与观察到的实验数据之间的比较，以评估预测响应的准确性和可靠性。

The seismic behavior of ground-based liquid storage tanks under horizontal and vertical excitations has received considerable attention in the past two decades; however, most of these studies dealt only with the behavior of anchored tanks. Few attempts were made to analyze the complex behavior of unanchored tanks and models sought were either too simple to capture the basic response of such structures or too complicated by modeling many features at once. It is believed that the behavior of the bottom plate is a dominant factor in the analysis of the overall system. Also, based on past experimental tests, liquid sloshing has a more pronounced effect on the response of unanchored than anchored tanks. This research will conduct a comprehensive study to analyze the seismic response of unanchored tanks. The study consists of both theoretical and experimental investigations, and is divided to three major phases: 1. Nonlinear static and dynamic analyses of the response of the bottom plate of the tank under uplifting forces taking into account its nonlinear contact with the foundation, its large deformations, its inelastic response, its interaction with the underlying soil and its behavior under impact; 2. An analysis of the nonlinear response of the liquid, and an evaluation of the corresponding hydrodynamic pressures; and 3. An analysis of the coupled response of the shell, the liquid and the bottom plate under moderate to severe earthquake motions. The research will provide a comparison between theoretical results and observed experimental data to assess the accuracy and the reliability of the predicted response.