Earthquake Engng Struct Dyn. 2019;1–21. Summary This paper presents results of one‐g shake‐table tests on scoured pile‐group‐ supported bridge models in saturated (liquefiable) and dry (nonliquefiable) sands. The primary objective is to reveal the influence of liquefaction on seismic demands and failure mechanism of scoured bridges. To this end, two identical models, each consisting of a 2 × 2 reinforced concrete pile‐ group with a center‐to‐center spacing of 3 times pile diameter, a cap and a single pier with a lumped iron block, were constructed and embedded into saturated and dry sands, respectively, with the same scour depth of 4 times pile diameter. Typical test results, including excess pore pressure, acceleration and displacement demands are interpreted first, followed by the focus on curvature demands and associated seismic failure mechanism identification. Finally, inertial and kinematic effects on pile curvature demands are estimated using cross‐correlation analyses. Results show that near‐pile liquefied soils exhibit more remarkable dilation tendency as compared to far field. For bridges under the given scour depth, soil liquefaction tends to significantly affect the failure modes via transferring damage positions from pier bottom to pile head and meanwhile from underground pile to pile head. In addition, pile group effects appear to be significant in nonliquefiable soils while to be relatively inessential in liquefied soils. Moreover, the inertial effect is more prominent in nonliquefiable soils, while the kinematic effect itself generally appears to be more significant in liquefiable soils. The test results can be used to validate numerical models for future studies.

中文翻译：

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可液化和不可液化土壤中冲刷RC桩组支桥的振动台研究

地震工程结构动态。2019 年；1-21。总结 本文介绍了在饱和（可液化）和干燥（不可液化）砂土中冲刷桩组支撑桥梁模型的 1 g 振动台试验结果。主要目的是揭示液化对冲刷桥梁抗震要求和破坏机制的影响。为此，建造并嵌入了两个相同的模型，每个模型由中心距为桩径 3 倍的 2 × 2 钢筋混凝土桩组、帽和带有集总铁块的单墩组成。分别冲入饱和砂和干砂，冲刷深度相同，为桩径的 4 倍。首先解释典型的测试结果，包括超孔隙压力、加速度和位移要求，其次是关注曲率需求和相关的地震破坏机制识别。最后，使用互相关分析估计惯性和运动学对桩曲率需求的影响。结果表明，与远场相比，近桩液化土表现出更显着的膨胀趋势。对于给定冲刷深度下的桥梁，土壤液化往往通过将破坏位置从桥墩底部转移到桩头，同时从地下桩转移到桩头来显着影响破坏模式。此外，桩群效应在非液化土壤中似乎很显着，而在液化土壤中则相对无关紧要。此外，惯性效应在不可液化土壤中更为突出，而运动学效应本身在可液化土壤中通常显得更为显着。