Rocking Isolation of Frames on Isolated Footings: Design Insights and Limitations
Rocking Isolation of Frames on Isolated Footings: Design Insights and Limitations
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独立基础上框架的摇摆隔离：设计见解和局限性
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
I. Anastasopoulos
中科院分区：
文献类型：
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作者：
R. Kourkoulis;F. Gelagoti;I. Anastasopoulos
到目前为止，一个重要的研究工作已经致力于试图引入新的地震保护计划，利用非弹性基础响应的动员。根据这种新兴的抗震设计概念，称为“摇摆隔离”，而不是过度设计框架的基脚（如在传统的能力设计），他们是故意设计不足，以促进提升和通过摇摆强烈的地震震动，从而限制传递到上部结构的惯性力。最近的研究已经证明了摇摆隔离的框架结构的抗震保护的潜在有效性，使用一个简单的单跨框架作为说明性的例子。这篇文章：（a）揭示了摇摆隔离可能存在的局限性，特别是考虑到土壤特性估计方面不可避免的不确定性;（B）研究了地面运动特性的潜在有害影响;（c）评估摇摆隔离对更复杂结构的有效性。结果表明，这一概念可以推广到2-bay框架，即使基础摇摆是有限的，积极的影响，基础设计仍然存在，特别是当它涉及到非常强烈的地震震动。相反，当框架受到水平和同步垂直加速度分量的组合时，其有效性可能受到限制-这是冲积盆地表面上的一种可能情况。
To date, a significant research effort has been devoted attempting to introduce novel seismic protection schemes, taking advantage of mobilization of inelastic foundation response. According to such an emerging seismic design concept, termed “rocking isolation,” instead of over-designing the footings of a frame (as in conventional capacity design), they are intentionally under-designed to promote uplifting and respond to strong seismic shaking through rocking, thus bounding the inertia forces transmitted to the superstructure. Recent research has demonstrated the potential effectiveness of rocking isolation for the seismic protection of frame structures, using a simple 1-bay frame as an illustrative example. This article: (a) sheds light in the possible limitations of rocking isolation, especially in view of the unavoidable uncertainties regarding the estimation of soil properties; (b) investigates the potential detrimental effects of ground motion characteristics; and (c) assesses the effectiveness of rocking isolation to more complex structures. It is shown that the concept may be generalized to 2-bay frames, and that even when foundation rocking is limited, the positive effect of foundation under-design remains, especially when it comes to very strong seismic shaking. In contrast, its effectiveness may be limited when the frame is subjected to combined horizontal and synchronous vertical acceleration components — a possible scenario on the surface of alluvial basins.