NEESR-CR: Design of Soil and Structure Compatible Yielding to Improve System Performance

NEESR-CR：土壤和结构兼容产量设计以提高系统性能

• 批准号: 0936503
• 负责人: Bruce Kutter
• 金额: $ 78.2万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0936503&HistoricalAwards=false
• 关键词: NEESR; CR; Design; Soil; Structure

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This award is an outcome of the NSF 09-524 program solicitation ''George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Research (NEESR)'' competition and includes the University of California, Davis (lead institution) and Santa Clara University (subaward), and the University of California, San Diego (subaward). This project will utilize the NEES equipment site at the University of California, Davis.Hundreds of billions of dollars and thousands of lives are at risk when a major earthquake shakes a metropolitan area. Building damage or collapse is one of the primary contributors to the risk. Huge investments are being made to improve performance of new and old structures by including structural or mechanical energy dissipation devices such as dampers (huge shock absorbers) and even complex computer controlled actuators to counteract effects of earthquake shaking. Geotechnical and structural engineers, however, generally understand that a lot of the damaging shaking energy can be effectively dissipated just by allowing the foundations to absorb the energy. Energy that would otherwise damage a building can be dissipated through friction at the soil-foundation interface as well as by radiation back into the ground. Civil engineers understand this today, but they are reluctant to design buildings with foundations that rock (just a little) due to: (i) the understandable perception that geotechnical material properties are less certain than structural material properties and (ii) the partition between structural and geotechnical responsibility in our traditional engineering design process. (Presently, structural engineers design the part of the building above the ground and geotechnical engineers design the foundations, and there is minimal interaction between the two.)While it is clear that the bearing capacity of shallow foundations is very sensitive to uncertain soil properties, the moment capacity of typical shallow foundations is much more predictable than the bearing capacity. Rocking has the added benefit of introducing a natural self-centering tendency; imagine tilting a refrigerator a few degrees, and then letting go ? the refrigerator will rock back and forth a little, but it will eventually end up standing vertical (this is what we mean by ?self-centering?. Geotechnical and structural engineers would need to work together to ensure that rocking movement of a foundation, for example, is compatible with the movement of the rest of the building. This work will bring together leaders in structural and geotechnical engineering from universities and private engineering firms to figure out how to perform the collaborative holistic building design that allows us to design buildings that can move with a rocking foundation and hence allow us to take advantage of cost effective energy dissipation in the foundation. A strong technology transfer team that includes practicing engineers will work with the academics in this project to help ensure that innovative concepts are not impractical. Teaming with construction and practicing engineers actively involved in building code revision will also help speed our results toward adoption by the profession.Avoiding over-designed, over-conservative footings and reducing requirements for energy dissipation mechanisms within the superstructure will save construction costs and can improve performance. There is almost no experimental data available to indicate how rocking foundations will dynamically interact with a yielding structural system. This proposal will fill this gap by performing experiments on a NEES centrifuge facility. Computer simulations validated by experiments will be used to generalize findings over a larger range of prototype situations. Although our work focuses on buildings, the use of inelastic soil-foundation behavior incorporating energy dissipating and self-centering is applicable to a large array of bridges, towers, and taller buildings. Improved performance will lead to a reduction in economic and human losses associated with earthquakes. An effort to recruit new engineers by inviting groups of students in MESA (an organization that helps educationally disadvantaged students succeed in Math, Engineering, and Science) programs at local community colleges learn about civil engineering will help grow a diverse engineering workforce. Data from this project will be archived and made available to the public through the NEES data repository.

该奖项是根据2009年的《美国复苏与再投资法》（公法111-5）资助的。该奖项是NSF 09-524计划的结果。 （subaward）。 该项目将利用加州大学戴维斯分校的NEES设备网站。当大地震席卷大都市地区时，数十亿美元和数千人的生命正处于危险之中。 建造损害或崩溃是风险的主要因素之一。 通过包括结构性或机械能量耗散设备，例如阻尼器（巨大的减震器），甚至复杂的计算机控制的执行器，以抵消地震震动的影响，从而提高了新旧结构的性能，以提高新旧结构的性能。 然而，岩土工程师通常了解，仅通过允许基础吸收能量，就可以有效地消散许多有害的摇动能量。 否则会损坏建筑物的能量可以通过土壤发现界面以及辐射回到地面的摩擦来消散。 土木工程师今天了解这一点，但由于以下基础，他们不愿意设计建筑物，因为：（i）可以理解的是，可以理解的是，岩土技术材料的特性不如结构材料属性确定，并且（ii）在我们传统的工程设计过程中结构性和地理位置责任之间的分区。 （目前，结构工程师设计了建筑物的一部分，岩土工程师设计了基础，并且两者之间的相互作用最少。）虽然很明显，浅基础的轴承能力对不确定的土壤特性非常敏感，但典型的浅基础的矩量比轴承能力更为可预测。 摇摆具有引入​​自然自我居中趋势的额外好处；想象一下，将冰箱倾斜几个度，然后放开？冰箱会来回摇摆，但最终将最终垂直站立（这是我们的意思吗？自我居中？岩土和结构工程师需要共同努力，以确保基金会的摇摆动作，例如，例如，建筑物的其余工作与私人工程领导者的努力相兼容。我们可以设计建筑物，使我们能够在基础上利用成本有效的能源耗散，其中包括实践工程师的强大技术转移团队将在该项目中与学者合作，以确保创新的概念与我们的构建代码相比，可以通过速度促进我们的成果，以确保构建工程师的努力。上层建筑内的基础和减少对耗能机制的要求将节省建筑成本并可以提高性能。 几乎没有可用的实验数据来指示摇摆基础将如何与屈服结构系统动态相互作用。 该提案将通过在NEES离心设施上进行实验来填补这一空白。 通过实验验证的计算机模拟将用于在更大范围的原型情况下概括发现。尽管我们的工作集中在建筑物上，但使用非弹性土壤发现的行为，包括消散和自我居中的能量，适用于大量的桥梁，塔楼和更高的建筑物。 提高的绩效将导致与地震相关的经济和人类损失减少。 通过邀请梅萨（Mesa）的一群学生（一个帮助教育不利的学生在数学，工程和科学上取得成功的组织）计划来招募新工程师的努力。 该项目的数据将通过NEES数据存储库进行存档并提供给公众。