SEISMIC DESIGN OF FOUNDATIONS AND SOIL–STRUCTURE INTERACTION

SEISMIC DESIGN OF FOUNDATIONS AND SOIL–STRUCTURE INTERACTION
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地基抗震设计和土壤-结构相互作用

DOI:
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发表时间:
2006
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影响因子:
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通讯作者:
G. Gazetas
G. Gazetas
中科院分区:
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文献类型:
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作者:
G. Gazetas

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讨论了两个具有实际意义的主题:(a)广泛持有的看法,反映在大多数抗震规范中,土-结构相互作用(SSI)总是起着有益的作用(因此在设计中可以忽略,以确保安全)被证明是一个误解的结果,从目前的设计反应加速度谱的形状软/深土壤条件。在对记录的响应谱值进行统计处理之前,通过运动的主导周期对结构周期进行适当归一化,会产生完全不同的形状和谱坐标大小;因此,由于SSI而增加的周期可能会导致更高的响应。(b)近年来的分析、实验和现场证据已经开始表明,浅基础的抗震设计可以克服所谓的“承载力设计”的严格限制,允许发生显著的滑动、抬升甚至承载力失效机制的移动。结果表明,在地震条件下,这种动态非弹性-非线性响应可能只会导致可接受的永久水平和旋转变形。
Two topics of practical significance are discussed : (a) The widely-held perception, reflected in most seismic codes, that soil-structure interaction (SSI) plays invariably a beneficial role ( and thus can be ignored in design to be on the safe side) is shown to be the result of a misconception stemming from the shape of current design response acceleration spectra for soft/deep soil conditions. Properly normalising the structural period by a dominant period of motion before statistically processing recorded response spectral values, produces completely different shape and size of spectral ordinates ; thus an increased period due to SSI may lead to higher response. (b) Analytical, experimental and field evidence in recent years has started revealing that seismic design of shallow foundations could overcome the strict limitations of the so-called “capacity design”, by allowing significant sliding, uplifting, and even mobilisation of bearing–capacity failure mechanisms to occur. It is shown that under seismic conditions such dynamic inelastic– nonlinear response may merely lead to acceptable permanent horizontal and rotational deformations.