NEESR Planning/Collaborative Research: Simulation and Design Tools for Tsunami Bridge Engineering

该项目的技术目标是为桥梁制定海啸荷载和设计建议，以解决必须区别对待桥梁和建筑物的问题。这些问题包括：(1)桥面形状、斜度和路堤等三维桥梁几何形状，其水力特性可导致沟道化、钻孔卡住和屏蔽；(2)泥石流冲击和泥石坝筑坝，在海啸波的初始冲击期间和流出期间，都可能极大地增加对桥梁的作用力；(3)流固相互作用效应，对于特定类型的桥梁和翻新战略，例如部署护板或在具有灵活结构的情况下，流固结构相互作用可能非常重要。还将探讨针对桥梁的翻新战略。并行处理软件发展的最新进展和强大的计算平台的可用性使模拟这些复杂的效应成为可能。计算流体动力学(CFD)建模将解决三维水力几何形状的影响。物质点法(MPM)将通过对碎片进行显式建模来处理碎片撞击场和筑坝的影响。OpenSees中实现的粒子有限元方法(PFEM)将允许研究人员考虑流固耦合、前一次地震震动的影响以及不确定因素的影响。作为这项规划赠款的一部分，将充分制定模拟战略，以指导2015财年初NEES2设施中关键实验的详细设计。在过去十年中，海啸造成了数十万人死亡和数千亿美元的损失。关键生命线结构的丧失延误了应急努力和灾后经济复苏，加剧了这些灾难。大海啸还威胁到美国至少五个州和许多美国领土。几乎所有过去的海啸研究都集中在启动模型、疏散策略的制定，以及最近的建筑物抵抗海啸的设计上。相比之下，很少有研究涉及桥梁的海啸性能，也没有指导方针来设计安全、经济的抗海啸桥梁或制定改造战略。为此，拟议的研究将改变抗海啸桥梁的设计，从而极大地改善灾后反应和恢复工作。该项目的数据将被存档，并通过NEES数据库向公众提供。该奖项是国家减少地震灾害计划(NEHRP)的一部分。

The technical objective of this project is to develop tsunami loading and design recommendations for bridges that address issues that must be treated differently for bridges than for buildings. These issues include (1) three-dimensional bridge geometries such as deck shape, skew and embankments, whose hydraulic characteristics can lead to channelization, bore entrapment, and shielding; (2) debris impact and debris damming that can greatly increase the forces on a bridge, both during the initial impact of the tsunami waves and during the outflows; and (3) fluid-structure interaction effects that can be significant for particular types of bridges and retrofit strategies, such as the deployment of fenders or in cases with flexible structures. Bridge-specific retrofit strategies will also be explored. Recent advances in the development of parallel processing software and the availability of powerful computational platforms make it possible to simulate these complex effects. Computational fluid dynamics (CFD) modeling will address the effects of three-dimensional hydraulic geometries. The Material Point Method (MPM) will address the effects of debris impact fields and damming by modeling debris explicitly. The Particle Finite Element Method (PFEM), as implemented in OpenSees, will allow researchers to consider the fluid-structure interaction, the effects of the preceding earthquake shaking and the effect of uncertainties. As part of this planning grant, the simulation strategies will be developed sufficiently to guide the detailed design of critical experiments in a NEES2 facility early in FY2015. Over the past decade, tsunamis have caused hundreds of thousands of deaths and hundreds of billions of dollars of damage. The loss of critical lifeline structures has exacerbated these catastrophes by delaying emergency response efforts and post-event economic recovery. Large tsunamis also threaten at least five U.S. states and numerous U.S. territories. Nearly all past tsunami research has focused on run-up modeling, the development of evacuation strategies, and more recently, on the design of buildings to resist tsunamis. In comparison, little research has addressed the tsunami performance of bridges, and no guidelines are available to design safe and economical tsunami-resistant bridges or to develop retrofit strategies. To these ends, the proposed research will transform the design of tsunami-resistant bridges, and consequently, greatly improve post-event response and recovery efforts. Data from this project will be archived and made available to the public through the NEES data repository. This award is part of the National Earthquake Hazards Reduction Program (NEHRP).