Empirical Evaluation of Soil-Structure Interaction Effects

作者：Clifford Astill castill@nsf.gov 注释 日期：3/22/98 6:21 PM 优先级：正常 收件人：acoles at nsf18 主题：摘要：CMS-9733113，Jonathan Stewart，UCLA ------------------------------ 消息内容 ----------------- -------------- 摘要：CMS-9733113，Jonathan Stewart，UCLA 地震震源建模的最新改进，在分析行进路径效应以及表征强烈地面震动对当地场地的影响方面，已经在基于代码和更先进的地震地面运动评估程序方面取得了重大进展。 同时，抗震结构设计实践正在朝着考虑基于性能的标准发展，这些标准提供了地震期间结构行为的更可靠的表示。然而，缺少的一环是经过经验验证的设计程序，用于评估土壤-结构相互作用（SSI）对传递到结构的强运动以及对这些运动的结构响应的影响。 幸运的是，在过去十年中已经获得了大量的强运动数据，这为获得这种经验验证提供了机会。 这是这个职业项目的目标。 该项目的研究部分利用系统识别分析中的强运动数据，通过更基本的 SSI 表示来评估惯性和运动相互作用对建筑物地震响应的影响；即阻抗和传递函数。这些经验结果是根据对具有结构和自由场强运动记录的适当组合的数据的分析而编制的。从强运动数据得出的经验结果与结构受迫振动测试的数据和数值分析的结果相结合，开发了一个框架来理解影响阻抗和传递函数的因素。这些结果将阐明 SSI 分析程序中不确定性的几个重要来源，例如非均匀场地条件的建模，以及地基埋置和/或深地基元素（即桩和桥墩）对地基性能的影响。 该项目的教育部分旨在改善加州大学洛杉矶分校的地震工程教学，加强向执业工程师的知识转移，并鼓励大学预科学生从事科学和技术职业。通过课程改革（包括增加新课程）以及采用将基础理论与“现场”数据和实际设计问题相结合的教学风格，加州大学洛杉矶分校的地震和岩土工程教学在本科和研究生阶段得到了改善。 通过继续教育研讨会和专业委员会的服务，促进了向执业工程师的知识转移。 对大学预科学生的宣传包括在当地初中和高中科学课程中进行讲座和演示。该研究计划通过提供可用于课堂教学的“现场”数据来补充这些教育目标。 这些统一的教育和研究计划反映了这样的理念：复杂地震和岩土现象的研究和教学必须将合理的物理原理与有据可查的现场性能数据相结合，以便深入了解问题。 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Clifford J. Astill 电话：703-306-1362 传真：703-306-0291castill@nsf.gov Nat'l Science Fdn 4201 Wilson Blvd., Rm545 Arlington, VA 22230 www.eng.nsf.gov/cms/castill.htm

Author: Clifford Astill castill@nsf.gov at NOTE Date: 3/22/98 6:21 PM Priority: Normal TO: acoles at nsf18 Subject: Abstract: CMS-9733113, Jonathan Stewart, UCLA ------------------------------- Message Contents ----------------- -------------- Abstract: CMS-9733113, Jonathan Stewart, UCLA Recent improvements in seismological source modeling, in the analysis of travel path effects, and in the characterization of local site effects on strong ground shaking, have led to significant advances in both code-based and more advanced procedures for evaluating earthquake ground motions. Concurrently, seismic structural design practice is evolving towards consideration of performance-based criteria, which provide more reliable representations of structural behavior during earthquakes. A missing link, however, is empirically verified design procedures for assessing the effects of soil-structure interaction (SSI) on both the strong motions transmitted to structures and the structural response to these motions. Fortuitously, a significant amount of strong motion data has become available over the last decade which affords the opportunity to obtain this empirical verification. This is the objective of this CAREER project. The research component of this project utilizes strong motion data in system identification analyses to evaluate the effects of inertial and kinematic interaction on the seismic response of buildings through more fundamental representations of SSI; namely impedance and transfer functions. These empirical results are compiled from analyses of data having suitable combinations of structural and free-field strong motion recordings. Empirical results derived from strong motion data are combined with data from forced vibration testing of structures and results of numerical analyses to develop a framework for understanding the factors influencing impedance and transfer functions. These results will elucidate several important sources o f uncertainty in SSI analysis procedures, such as the modeling of non-uniform site conditions, and the effects of foundation embedment and/or deep foundation elements (i.e. piles and piers) on foundation performance. The educational component of this project seeks to improve the teaching of earthquake engineering at UCLA, to enhance knowledge transfer to practicing engineers, and to encourage pre-college students to pursue careers in science and technology. The teaching of earthquake- and geotechnical-engineering at UCLA is improved at the undergraduate and graduate levels through curriculum reform (including the addition of new courses), and the utilization of an instructional style which blends fundamental theory with "field" data and practical design problems. Knowledge transfer to practicing engineers is facilitated through continuing education workshops and service on professional committees. Outreach to pre-college students consists of lectures and demonstrations in local middle- and high-school science classes. The research plan compliments these educational objectives by providing "field" data that can be utilized in classroom instruction. These unified educational and research plans reflect the philosophy that research and teaching of complex seismic and geotechnical phenomena must blend sound physical principles with well documented field performance data in order to gain insight into a problem. +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+= + Clifford J. Astill Ph:703-306-1362 Fax:703-306-0291 castill@nsf.gov Nat'l Science Fdn 4201 Wilson Blvd., Rm545 Arlington, VA 22230 www.eng.nsf.gov/cms/castill.htm