Experimental and Analytical Seismic Studies of MRF's and MRF-CBF Dual Systems with Concrete Filled Tube Members

建筑物的组合结构为抵抗非地震(如重力和风)荷载提供了一种有效的系统。钢管混凝土柱是组合结构的一种形式。到目前为止，在美日地震工程合作研究计划下进行的钢管混凝土相关研究已经调查了单个构件和连接在地震荷载条件下的性能。然而，由于目前对钢管混凝土框架及相关节点的抗震性能缺乏了解，本课题将重点研究钢管混凝土结构框架体系的抗震性能。该项目将：(1)研究钢管混凝土柱宽翼缘梁式磁流变框架的抗震性能；(2)研究钢管混凝土柱和钢管混凝土支撑组合框架体系的抗震性能；(3)评估钢管混凝土柱宽翼缘梁式组合框架和钢管混凝土柱组合框架体系的分析建模和分析方法；(4)审查和改进钢管混凝土构件结构框架体系的设计准则和方法。分析研究将集中在磁流变液和磁流变液-CBF双重系统的非线性时程分析上。利用改进后的设计准则，设计了三个钢管混凝土试件。每个测试框架将是为美日合作计划主题结构设计的两舱六层框架中较低三层的5/6比例模型。这三种框架包括：(1)方钢管混凝土柱和宽翼梁的MRF-CBF双重体系；(2)方钢管混凝土柱和无粘结支撑的MRF-CBF双重体系；以及(3)方钢管混凝土柱和有粘结支撑的MRF-CBF双重体系。试验研究将在每个试验框架上进行一系列拟静力试验，使用模拟地震荷载，该荷载包括施加在第一、第二和第三层楼层的横向位移历史。该项目将获得从孤立构件和连接研究中无法获得的关于钢管混凝土构件结构体系抗震性能的新知识，并将产生设计专业人员用于组合结构体系抗震设计所需的技术信息。该项目得到了NSF94-154“美日合作复合材料和混合结构研究”倡议的支持。

Composite construction for buildings provides an effective system for resisting non-seismic (e.g., gravity and wind) loads. Concrete filled steel tube (CFT) columns are one form of composite construction. CFT-related research studies to date under the U.S.-Japan Cooperative Research Program on Earthquake Engineering have investigated the performance of individual members and connections under seismic loading conditions. However, there currently is a lack of knowledge of the seismic performance of complete structural frames with CFT members and related connections.This project will focus on the seismic performance of CFT structural frame systems. The project will: (1) investigate the seismic performance of CFT column-wide flange beam MRF; (2) investigate the seismic performance of MRF-CBF dual frame systems with CFT columns and CFT braces; (3) evaluate analytical modeling and analysis procedures for CFT column-wide flange beam MRFs and MRF-CBF dual frame systems with CFT columns and CFT braces; and (4) review and improve design criteria and methodologies for structural frame systems with CFT members.The objectives of the project will be achieved through integrated analytical and experimental investigations. The analytical investigation will focus on nonlinear time history analysis of MRFs and MRF-CBF dual systems. Using the improved design criteria, three CFT test frames will be designed. Each test frame will be a 5/6 scale model of the lower three stories of a two-bay six-story frame designed for the theme structure of the U.S. Japan Cooperative Program. The three frames include: (1) and MRF with square CFT columns and wide flange beams; (2) an MRF-CBF dual system with square CFT columns and CFT unbonded braces; and (3) a MRF-CBF dual system with square CFT columns and CFT bonded braces. The experimental investigation will execute a series of pseudo-static tests on each test frame using a simulated seismic loading that consists of imposed lateral displacement histories at the first, second, and third floor levels. The project will acquire new knowledge of the seismic performance of structural systems with CFT members that cannot be obtained from studies of isolated members and connections, and will generate technical information needed by design professionals for the seismic resistant design of composite structural systems. This project is supported under initiative NSF94-154 "US-Japan-Cooperative Research in Composite and Hybrid Structures."