A Deformation Based Methodology for the Evaluation and Upgrading of Existing Structures

9319434 Krawinkler该项目涉及制定评估和加固现有结构的形变方法所需的基本概念和基本信息。这一方法的目的是：(1)评估现有结构的预期抗震性能并确定基本加固需求；(2)促进制定有效的加固方案，并提供加固方案各组成部分所需强度和变形能力的目标值；(3)核查加固结构的抗震性能，并为加固方案各要素的微调提供信息；(4)提供有关变形需求的信息，这些信息将支配对加固方案各要素的详细规定。在反映控制抗震性能的物理现象的形变基础评估/加固方面一直存在知识空白，这项研究旨在填补大部分空白。对以下三个问题进行了研究：(1)单自由度和多自由度体系地震强度和位移需求的量化；(2)作为评估/验证过程一部分的“推覆”分析的执行和评估程序和标准的制定；(3)形变法概念的形式化，使其成为工程专业的一种可行和有吸引力的工具。这项研究的成功完成将使人们有可能采取一种办法来修复和加固易受地震影响的结构。这是推进实践状态并将变形控制作为设计过程中被接受的一部分的独特机会。这是美国国家科学基金会“结构抗震修复与恢复研究”的一个奖项。*

9319434 Krawinkler This project is concerned with the development of basic concepts and fundamental information needed to formalize a deformation based methodology for the evaluation and strengthening of existing structures. This methodology is intended to (1) permit an assessment of the expected seismic performance of existing structures and the identification of basic strengthening needs, (2) facilitate the development of an effective strengthening scheme and provide target values for the required strength and deformation capacities of the components of the strengthening scheme, (3) permit a verification of the seismic performance of the strengthened structure and provide information for fine-tuning of the elements of the strengthening scheme, and (4) provide information on the deformation demands that will govern requirements for detailing of the elements of the strengthening scheme. There have been knowledge gaps in deformation base evaluation/strengthening which reflects the physical phenomena that control seismic performance and this research is intended to fill most of these gaps. Research is conducted on the following three topics: (1) Quantification of seismic strength and displacement demands for Single- Degree-of-Freedom and Multiple-Degree-Of-Freedom systems, (2) development of procedures and criteria for the execution and evaluation of a "push-over" analysis that is to be employed as part of the evaluation/verification process, and (3) formalization of the concepts of the deformation method to the extent that it can become a feasible and attractive tool for the engineering profession. A successful completion of this research will make it possible to implement an approach to repairing and strengthening of seismically vulnerable structures. It represents a unique opportunity to advance the state of the practice and introduce deformation control as an accepted part of the design process. This is an award under NSF-Initiative "Repair and Rehabilitation Research for Seismic Resistance of Structures." ***