PERFORMANCE OF A SOIL-STRUCTURE SYSTEM UNDER NEAR-SOURCE EARTHQUAKES

本研究的目的是研究近源地震的特征及其对结构-基础-土壤系统反应的影响，以及对次级结构的影响。为了减少近源强烈地震的影响，建议采用由钢弹簧和粘滞阻尼器组成的方法。研究表明：在某些结构位置，仅考虑水平地震动将导致不切实际的反应。当竖向地震动产生最大反应时，水平地震动不产生反应。结构中塑性铰的发展不会改变这一发现。水平地震动和竖向地震动的后续峰值的时间重合可以引起比水平地震动产生的反应大得多的反应。因此，应考虑地面同时激励，特别是在柔性结构的情况下。土壤对…有轻微的减小作用更具结构性的回应。对于二次结构的竖向响应，可以观察到高达100%的反应放大。因此，在设计中应考虑软土地基与结构的相互作用，即使支撑二次结构的结构构件在设置与不设置二次结构时的振动基本相同，二次结构与结构构件之间的相互作用也会导致二次结构的反应增大。对于敏感的二次结构，二次结构与结构构件之间的相互作用是非常重要的，所提出的折减方法不仅可以激发结构响应中的刚体运动，还可以激发结构在竖向和水平方向上的运动。粘性阻尼器减少了这些运动。这些主动刚体运动减小了结构构件的相对变形，在结构中产生较小的激发力，也可以减小二次结构的反应。较少

The objective of this study is to investigate the characteristics of near-source earthquakes and their effect on the response of a structure-foundation-soil system as well as on the secondary structures. To reduce the effect of strong near-source earthquakes an approach consisting of steel springs and viscous dampers is recommended.The investigations reveal:At certain structure locations a consideration of horizontal ground motions alone will lead to an unrealistic response. While the vertical ground motions produces the maximum response, the horizontal ground motions produces no response.The development of plastic hinges in the structure does not change this finding.The time coincidence of subsequent peaks of the horizontal and vertical ground motions can cause much larger response than that produced by the horizontal ground motions. A simultaneous ground excitation should be therefore considered, especially in case of flexible structures.The soil has a slight reduction effect on the … More structural response. For the vertical response of the secondary structure, however, response amplification up to 100% can be observed. Consequently, in the design the soft ground-structure interaction should be considered.The effect of the interaction between secondary structure and structural member (SsSI) can cause an increase of the response of secondary structures, even though the vibration of the structural member, which supports the secondary structure, with and without SsSI are almost the same. For the design of a sensitive secondary structure the interaction between secondary structure and structural member is important.The introduced reduction approach can activate rigid body motions in the structural response, not only in the horizontal but also in vertical direction. The viscous dampers reduce these motions. These activated rigid body motions reduce the relative deformation of the structural members, and cause smaller activated forces in the structure.A reduction of the response of secondary structures can also be achieved. Less