Analysis of Improved Ground and Reinforced Soil Systems Performance during the 1999 Turkey and 2001 Nisqually Earthquakes - Part 1 Reinforced Soil Structures

0201508，詹姆斯·R·马丁，弗吉尼亚理工学院，《1999年土耳其和2001年尼斯奎利地震中改进的地基和加筋土系统性能的分析：加筋土结构》加筋土结构，如土钉墙和机械稳定路堤，已被证明是传统挡土结构的可行替代方案。它们正变得越来越受欢迎，设计也变得更具挑战性，因为墙更高，加固和饰面材料的种类也更多。静力条件下的设计方法已经相当成熟；然而，缺乏关于抗震性能的知识，并且相应地缺乏全面的抗震设计程序。由于记录在案的地震现场性能数据的稀缺，目前的指导方针非常有限，而且是基于概括性的假设。此外，没有可以用来预测永久墙体位移的简化方法--通常是控制使用性能的标准。虽然已经进行了一些离心机和振动台模型实验来模拟地震载荷，但这些实验并不是为了帮助改进设计程序的发展。为了全面了解加筋土结构的地震行为并制定改进的抗震设计指南，需要进行实例分析、参数数值研究和额外的模型试验。土耳其1999年7级以上地震影响区内的16个以上加筋土结构以及与台湾和华盛顿州西雅图大地震有关的4面墙提供了一个独特的机会来评估这些系统在不同地面震动水平和不同土壤条件和性能水平下的行为。通过现场勘察研究，首席调查员收集了所需的性能数据、施工细节和地基数据，提供了一个全面的墙体性能数据库。对已确定的最有希望和可能具有指导意义的加固土系统进行详细的案例分析，并将发现记录在案；使用现场案例来校准和/或评估数值模式的预测能力；进行动态参数数值分析，以建立行为趋势，并有效扩展地震荷载下墙性能的数据库；以及，4.)该项目是弗吉尼亚理工大学与土耳其博加齐奇大学和泽塔斯公司的研究人员之间的合作，并与土耳其的一个合作项目相衔接，该项目涉及弗吉尼亚理工大学、瑞士联邦理工学院、博加齐西大学和横滨国立大学。它还解决了联邦公路管理局在第82号示范项目(1999年)中确定的加筋土系统现行抗震设计方法的局限性。

0201508, James R. Martin, Virginia Polytechnic Institute"Analysis of Improved Ground and Reinforced Soil System Performance During the 1999 Turkey and 2001 Nisqually Earthquakes: Reinforced Soil Structures"Reinforced soil structures, such as soil-nailed walls and mechanically-stabilized embankments, have been shown to be feasible alternatives to conventional earth retaining structures. They are becoming increasingly popular, and designs are becoming more challenging with taller walls and a wider variety of reinforcing and facing materials. Design methods for static conditions are fairly well established; however there is a lack of knowledge regarding seismic performance, and a corresponding lack of comprehensive seismic design procedures. Current guidelines are very limited and are based on generalized assumptions due to the scarcity of documented seismic field performance data. Also, there are no simplified methods that can be used to predict permanent wall displacement - often the controlling serviceability criterion. Although some centrifuge and shake table model experiments have been performed to simulate seismic loadings, these experiments were not designed to assist in the development of improved design procedures. There is a need for case history analysis, parametric numerical study, and additional model experiments to fully understand the seismic behavior of reinforced soil structures and to develop improved seismic design guidelines.A unique opportunity to evaluate the behavior of these systems under a range of ground shaking levels and for a variety of soil conditions and performance levels is provided by the more than sixteen reinforced-soil structures located within the affected region of the M (7+) 1999 earthquakes in Turkey, and four walls associated with large earthquakes in Taiwan and Seattle, WA. Through field reconnaissance studies, the principal investigator collected required performance data, construction details, and subsoil data, providing a comprehensive database of wall performance.The objective of this research project is to: 1.) perform a detailed case history analysis of the most promising and potentially instructive reinforced soil systems identified, and document the findings; 2.) use the field cases to calibrate and/or assess the predictive capability of the numerical models; 3.) perform dynamic parametric numerical analyses to establish behavioral trends and effectively extend the database of wall performance under seismic loading; and, 4.) use this data to develop improved seismic design guidelines for reinforced soil structures.The project ivolves a collaboration between Virginia Tech and Turkish researchers at Bogazici University and Zetas, Inc, and interfaces with a collaborative microzonation project in Turkey involving Virginia Tech, the Swiss Federal Institute of Technology, Bogazici University, and Yokohama National University. It also addresses limitations in current seismic design methods for reinforced-soil systems that have been identified by the Federal Highway Administration in Demonstration Project No. 82 (1999).