Abstract The paper revisits the notorious collapse of 18 spans of the elevated Route No. 3 of Hanshin Expressway during the 1995 Kobe earthquake. The overturned deck was monolithically connected to 3.1 m diameter piers, which failed dramatically. In stark contrast, the massive 17–pile groups survived the earthquake and are still in use, supporting the new bridge. The scope of the study is dual. Initially, the actual pile group–bridge–soil system is investigated employing the finite element (FE) method, accounting for material and geometric nonlinearities. Reinforced concrete (RC) members (pier and piles) are modelled using the Concrete Damaged Plasticity (CDP) model, while a kinematic hardening model is employed for the soil. The numerical simulation reproduces the observed shear-dominated failure at the region of reinforcement cut-off. The analysis reveals that the pile group sustains non-negligible rocking during shaking (despite being over-designed), leading to alternating tension and compression of the edge piles, combined with shear-moment loading. The resulting stiffness reduction of the cracked under tension piles leads to load redistribution towards the stiffer compressed piles, preventing plastic hinging of the weaker piles (under tension). These findings are consistent with post-earthquake in-situ testing, qualitatively verifying the numerical analysis technique. Subsequently, alternative foundation concepts are explored, starting with the pilecap of the original configuration acting as a shallow footing, provoking nonlinear rocking response. It is shown that soil yielding acts as a “fuse”, preventing collapse at the cost of increased settlements and limited residual foundation rotation. The benefits and limitations of such a shift towards nonlinear soil–foundation response are further explored, studying four intermediate foundation schemes.

中文翻译：

---

深江大桥倒塌（Kobe 1995）重温：新见解

摘要 本文回顾了 1995 年神户地震期间阪神高速 3 号线高架 18 跨度的坍塌事故。翻倒的甲板整体连接到直径为 3.1 m 的桥墩，但严重失效。与此形成鲜明对比的是，巨大的 17 桩组在地震中幸存下来并仍在使用中，支撑着新桥。研究范围是双重的。最初，使用有限元 (FE) 方法研究了实际的桩群-桥梁-土壤系统，考虑了材料和几何非线性。钢筋混凝土 (RC) 构件（桥墩和桩）使用混凝土损伤塑性 (CDP) 模型进行建模，而土壤则采用运动硬化模型。数值模拟再现了观察到的钢筋截断区域的剪切主导破坏。分析表明，桩组在震动期间承受不可忽略的摇摆（尽管过度设计），导致边缘桩的交替拉伸和压缩，以及剪切力矩载荷。受拉开裂桩的刚度降低导致载荷重新分配到较硬的压缩桩，防止较弱的桩（受拉）发生塑性铰接。这些发现与震后原位测试一致，定性地验证了数值分析技术。随后，探索替代基础概念，从原始配置的桩帽作为浅基础开始，引发非线性摇摆响应。结果表明，土壤屈服起到了“保险丝”的作用，以增加沉降和限制剩余地基旋转为代价来防止倒塌。通过研究四种中间地基方案，进一步探讨了这种向非线性土 - 地基响应转变的好处和局限性。