NEESR-GC: Mitigation of Collapse Risk in Vulnerable Concrete Buildings

这一多机构奖项是NSF 06-504项目征集“小乔治·E·布朗地震工程模拟研究网络(NEESR)”竞赛的结果。美国最大的总体地震风险之一是旧混凝土建筑在城市大地震中倒塌的风险，但目前还没有以经济高效的方式解决这一问题的解决方案。政策制定者和建筑业主对翻新大量现有建筑库存的成本感到沮丧。工程师需要工具来准确评估个别建筑的风险，并区分适当的建筑和潜在的危险建筑，以便建筑所有者可以优先考虑缓解费用。监管机构需要关于区域风险程度的更好信息，以便能够制定有效的政策措施，以实现区域缓解努力。该项目将研究普遍存在的高风险的老旧非延性混凝土建筑的倒塌潜力，以改进和传播有效的工程评估和翻新工具，并确定适当的激励或政策措施来降低风险。这项研究将调查四个方面：1)暴露-将选择一个单一的城市区域作为其他地区的模型，并将开发适用于研究老式混凝土建筑区域倒塌风险的清单模型；2)构件和系统性能-将对构件、组件和土-基础-结构系统进行实验室和现场试验，以更好地了解导致倒塌的条件；3)建筑和区域模拟-模型将在对地震工程师有用的非线性动力分析软件中开发和实施，并将通过区域动态模拟扩展结果，以帮助了解建筑物在大地震中倒塌的区域分布；以及4)缓解战略-将制定有效的缓解战略，并建立包括工程师、规划者、政策专家和利益相关者在内的联盟，以促进降低风险的行动。该计划的特色是一个重要的教育组成部分，旨在增加地震工程、国际合作和向广大社区传播成果的多样性。智力上的优势在于多学科的挑战，即理解三维荷载下的坍塌条件和机制，在可用于单个建筑分析的软件中实施这一理解，并将理解扩展到区域层面，在那里，工程科学、经济学和公共政策的交叉将为推荐最佳缓解策略提供合理的基础。该项目的更广泛影响是广泛的。该研究计划解决了一个重要而具有挑战性的问题，这将促进对地震工程的发现和理解。该教育计划将使不同人群的本科生接触到该计划，并推动顶尖候选人进入研究生研究。将通过多种方式传播研究成果，包括：利用国家地震研究中心的资源分享成果，让地震专业人员和城市规划者参与进来，以及传播教育材料。结果将有助于确定适当的工程和公共政策解决方案，以解决现有危险建筑建设的问题，从而使社会受益。更好地了解建筑物在地震期间的倒塌也将有助于了解脆弱性和加强基础设施以抵御爆炸物和撞击危险的影响。本项目制定的减灾战略也可为减轻飓风等其他自然灾害的战略提供参考。该项目使用了加州大学伯克利分校、加州大学洛杉矶分校、加州大学圣巴巴拉分校和明尼苏达大学的NEES设备站点。

This multi-institution award is an outcome of the NSF 06-504 program solicitation "George E. Brown, Jr. Network for Earthquake Engineering Simulation Research (NEESR)" competition. One of the greatest overall seismic risks in the United States is the risk of collapse of older concrete buildings in a major urban earthquake, yet there are no solutions to how to address this in a cost-effective manner. Policy makers and building owners are frustrated by the costs of retrofitting large inventories of existing buildings. Engineers need tools to accurately assess the risk of individual buildings and to differentiate between adequate buildings and potentially hazardous ones, so building owners can prioritize mitigation expenses. Regulatory agencies need better information on the regional extent of the risk so that effective policy measures can be put in place to effect regional mitigation efforts. This project will study the collapse potential of older nonductile concrete buildings, which are pervasive and high risk, to improve and disseminate effective engineering assessment and retrofit tools and to define appropriate incentive or policy measures to mitigate the risk. The research will investigate four areas: 1) Exposure - a single urban region will be selected to serve as a model for other regions, and an inventory model suitable to study the regional collapse risk of older type concrete buildings will be developed; 2) Component and System Performance - laboratory and field experiments will be conducted on components, subassemblies, and soil-foundation-structure systems to better understand conditions that lead to collapse; 3) Building and Regional Simulation - models will be developed and implemented in nonlinear dynamic analysis software useful to earthquake engineers, and results will be extended through regional dynamic simulations to help understand the regional distribution of building collapses in a major earthquake; and 4) Mitigation Strategies - effective mitigation strategies and coalitions involving engineers, planners, policy experts, and stakeholders will be developed to promote action for risk reduction. The program features a significant education component aimed at increasing diversity in earthquake engineering, international collaborations, and outreach to disseminate results to a broad community.The intellectual merit lies in the multi-disciplinary challenge of understanding the conditions and mechanics of collapse under three-dimensional loading, implementing that understanding in software usable for individual building analysis, and extending the understanding to the regional level where the intersection among engineering science, economics, and public policy will provide a rational basis for recommending the best mitigation strategies.The broader impacts of the project are extensive. The research program tackles an important and challenging problem that will advance discovery and understanding of earthquake engineering. The education program will expose a diverse population of undergraduates to the program and promote top candidates into graduate research. The results of the research will be disseminated in several ways, including: by sharing results using the NEES resources, by involving earthquake professionals and urban planners, and by disseminating educational materials. The results will benefit society by helping define appropriate engineering and public policy solutions to address the problem of existing hazardous building construction. Better understanding collapse of buildings during earthquake will also contribute to knowledge on vulnerability and toughening of infrastructure against effects of explosive and impact hazards. Mitigation strategies developed in this project also can inform strategies to mitigate for other natural hazards such as hurricanes. This project uses the NEES equipment sites at the University of California, Berkeley, the University of California, Los Angeles, the University of California, Santa Barbara, and the University of Minnesota.