NEESR: Near Collapse Performance of Existing Reinforced Concrete Frame Buildings

在70年代中期以前修建的既有易损钢筋混凝土框架(RC)建筑中，柱的剪切轴向破坏是一种主要的地震风险。坍塌开始时与空间响应和系统负载重新分配能力相关的挑战尚未得到解决。当前地震恢复条款中的验收标准是在单元级别定义的，没有适当考虑系统的稳健性。将使用小乔治·E·布朗进行四组三维、地理分布的混合模拟(HS)。位于伊利诺伊大学厄巴纳-香槟分校的地震工程模拟网络(NEES)设施，用于获得一个典型的三维结构系统在单向和三轴地震地面运动下的倒塌响应。这项研究将调查、表征、建模和推导柱剪切轴向破坏对现有脆弱RC结构倒塌的影响的实用程序。该项目将开发系统级验收标准和分析工具，用于现有非延性RC框架结构的接近倒塌的抗震性能。该项目的数据将被存档，并通过NEES项目仓库/数据储存库向公众提供，网址为http://www.nees.org.该项目是东北大学和西密歇根大学的研究人员共同努力的成果。该项目利用NEES设施提供的独特的HS功能，通过整合大型物理实验和数值模型来模拟现有脆弱的RC建筑的接近倒塌响应。如果成功，这项研究项目将把脆弱建筑结构评估的理念从部件级评估转变为系统级评估。应用本项目中开发的系统级评估方法，可以通过识别和优先处理易受部分/全部坍塌影响的建筑物，为现有的非延性RC建筑物提供更有效和更具成本效益的修复方法。因此，可以对有限的资源进行最佳利用。一个多层次的教育和推广计划将为来自K-12、大学和代表性不足的群体的学生以及高中物理教师提供参与项目活动的机会。这将包括开发适合于小学、初中和高中学生的三个教学模块，涵盖地震工程基础知识和与倒塌分析相关的主题。该奖项是国家减少地震灾害计划(NEHRP)的一部分。

Column shear-axial failure in existing vulnerable reinforced concrete (RC) frame buildings constructed before the mid 1970's is a major seismic risk. The challenges associated with spatial response and system load redistribution capability at the onset of collapse has not been resolved yet. The acceptance criteria in current seismic rehabilitation provisions are defined at the element level with no due consideration for the system robustness. Four sets of three-dimensional, geographically distributed hybrid simulations (HS) will be conducted using the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) facility at the University of Illinois at Urbana-Champaign to obtain the response up to collapse of a representative three-dimensional structural system subjected to one-directional and tri-axial seismic ground motions. This research will investigate, characterize, model, and derive practical procedures for the consequences of column shear-axial failure on the collapse of existing vulnerable RC structures. The project will develop system-level acceptance criteria and analytical tools for near collapse seismic performance of existing non-ductile RC frame structures. Data from this project will be archived and made available to the public through the NEES Project Warehouse/data repository at http://www.nees.org. This project is a collaborative effort between researchers from Northeastern University and Western Michigan University.This project utilizes the unique HS capability provided by the NEES facility to simulate near collapse response of existing vulnerable RC buildings through the integration of large scale physical experiments and numerical models. If successful, this research project will shift the philosophy of structural assessment of vulnerable buildings from component-level to system-level evaluation. The application of system-level evaluation methods developed in this project can lead to more efficient and cost-effective rehabilitation methods for existing non-ductile RC buildings against collapse by identifying and prioritizing buildings susceptible to partial/total collapse. Thus, optimal use of limited resources can be made. A multi-level education and outreach program will provide students from K-12, college, and underrepresented groups, as well as high school physics teachers, with the opportunity to participate in project activities. This will include development of three teaching modules suitable for elementary, middle, and high school students covering the basics of earthquake engineering and topics relevant to collapse analysis. This award is part of the National Earthquake Hazards Reduction Program (NEHRP).