Experimental proof is provided of an unconventional seismic design concept, which is based on deliberately underdesigning shallow foundations to promote intense rocking oscillations and thereby to dramatically improve the seismic resilience of structures. Termed rocking isolation, this new seismic design philosophy is investigated through a series of dynamic centrifuge experiments on properly scaled models of a modern reinforced concrete (RC) bridge pier. The experimental method reproduces the nonlinear and inelastic response of both the soil-footing interface and the structure. To this end, a novel scale model RC (1:50 scale) that simulates reasonably well the elastic response and the failure of prototype RC elements is utilized, along with realistic representation of the soil behavior in a geotechnical centrifuge. A variety of seismic ground motions are considered as excitations. They result in consistent demonstrably beneficial performance of the rocking-isolated pier in comparison with the one designed conventionally. Seismic demand is reduced in terms of both inertial load and deck drift. Furthermore, foundation uplifting has a self-centering potential, whereas soil yielding is shown to provide a particularly effective energy dissipation mechanism, exhibiting significant resistance to cumulative damage. Thanks to such mechanisms, the rocking pier survived, with no signs of structural distress, a deleterious sequence of seismic motions that caused collapse of the conventionally designed pier. © 2014 The Authors Earthquake Engineering & Structural Dynamics Published by John Wiley & Sons Ltd.

中文翻译：

---

隔振非弹性 RC 桥墩的离心机建模


实验证明了一种非常规抗震设计理念，该理念基于故意设计不足的浅基础，以促进强烈的摇摆振荡，从而显着提高结构的抗震能力。这种新的抗震设计理念被称为“摇摆隔离”，是通过对现代钢筋混凝土 (RC) 桥墩的适当比例模型进行一系列动态离心实验来研究的。该实验方法再现了土基界面和结构的非线性和非弹性响应。为此，采用了一种新颖的比例模型 RC（1:50 比例），可以很好地模拟原型 RC 元件的弹性响应和失效，并真实地表示土工离心机中的土壤行为。各种地震地面运动被视为激励。与传统设计的码头相比，它们使隔振码头具有一致且明显有益的性能。惯性载荷和甲板漂移方面的地震需求都减少了。此外，地基隆起具有自定心潜力，而土壤屈服被证明可以提供特别有效的能量耗散机制，表现出对累积损伤的显着抵抗力。多亏了这样的机制，摇晃的桥墩才得以幸存，没有出现结构损坏的迹象，而一系列有害的地震运动导致了传统设计的桥墩倒塌。 © 2014 作者《地震工程与结构动力学》由 John Wiley & Sons Ltd 出版。