Impact of Falling Debris in Structural Collapse Progression

该奖项将提高建筑物的安全性和弹性，使工程界能够更好地了解由于地震、风、碰撞、退化、设计不良和施工错误等各种原因造成的建筑物倒塌过程。 结构倒塌可能是由于建筑物构件的局部失效而发生的。虽然潜在的局部破坏几乎是不可能消除的，倒塌的进展下降的结构构件的影响可以是有限的。 然而，目前的工程分析方法缺乏预测下落碎片的速度和形状、撞击能量损失以及结构元件对碎片撞击的反应的能力。因此，没有合适的方法来预测坠落的碎片是否会导致坍塌的进展。了解坠落的碎片如何导致进一步的倒塌，可以帮助我们找到阻止建筑物倒塌和防止死亡的技术。该奖项中开发的改进分析工具将有助于通过未来改进的规范规定和详细的标准来促进国家繁荣和福利，这些标准将为结构倒塌提供额外的抵抗力。 此外，该项目将向不同的高中生提供外联服务，并教育大学本科生和研究生。 该奖项有助于国家科学基金会（NSF）在国家地震灾害减少计划（NEHRP）和国家风暴影响减少计划（NWIRP）中的作用。该项目的目标是通过实验和分析研究，对坠落的结构碎片载荷有一个基本的了解。将开发改进的分析工具（建模方法和简化分析），以改进坍塌预测，并导致未来的设计，可以有效地限制坍塌的进展。该研究将产生关键的实验数据和分析模型，为三个基本的撞击问题提供答案：（1）坠落碎片的速度，形状和条件，（2）能量损失的数量和如何分析撞击，以及（3）撞击梁的动态响应（强度和延展性）。该项目将通过以下方式实现其目标：（1）分析以前的倒塌试验，以确定坠落碎片的速度、形状和条件;（2）实验落梁冲击试验，以评估冲击和强度的能量传递;以及（3）对下部结构和原型建筑进行详细的有限元法数值分析，以分析坠落碎片的影响，并提供经验证的建模方法。研究结果将用于开发详细和简化的分析工具，可以分析坠落的碎片，以预测崩溃的进展。 该项目的数据将存档在NSF支持的自然灾害工程研究基础设施（NHERI）数据库（https：//www.example.com）中。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。www.DesignSafe-ci.org

This award will lead to improved safety and resiliency of buildings by enabling the engineering community to better understand the collapse process of buildings due to various causes, such as earthquakes, wind, collision, deterioration, poor design, and construction errors. Structural collapse can occur due to local failures that progress throughout the building’s members. While the potential local failure is nearly impossible to eliminate, the progression of collapse by the impact of falling structural members can be limited. However, current engineering analysis methods are lacking in the ability to predict the velocity and shape of the falling debris, the loss of energy on impact, and the response of the structural elements to the debris impact. Therefore, there is no suitable way to predict if the falling debris will cause a progression of collapse. Understanding how falling debris can lead to further collapse can lead to techniques to halt collapse in buildings and prevent fatalities. The improved analysis tools developed in this award will serve to advance national prosperity and welfare through future improved code provisions and detailing standards that will provide additional resistance to structural collapse. In addition, this project will provide outreach to diverse high school students and educate college undergraduate and graduate students. This award contributes to the National Science Foundation (NSF) role in the National Earthquake Hazards Reduction Program (NEHRP) and the National Windstorm Impact Reduction Program (NWIRP). The goal of this project is to achieve a fundamental understanding, through experimental and analytical studies, of falling structural debris loading. Improved analysis tools (modeling methods and simplified analysis) will be developed to improve collapse prediction and lead to future designs that can efficiently limit collapse progression. The research will generate critical experimental data and analytical models to provide answers to three fundamental impact questions: (1) velocity, shape, and condition of the falling debris, (2) amount of energy lost and how to analyze the impact, and (3) dynamic response (strength and ductility) of the impacted beam. The project will achieve its goal through (1) analysis of previous collapse tests to determine the velocity, shape, and condition of falling debris, (2) experimental drop beam impact tests to evaluate energy transfer on impact and strength, and (3) detailed finite element method numerical analysis of substructure and prototype buildings to analyze the effects of falling debris and provide validated modeling approaches. The results will be used to develop detailed and simplified analytical tools that can analyze falling debris for prediction of collapse progression. Data from this project will be archived in the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) Data Depot (https://www.DesignSafe-ci.org).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.