Development of Link-to-Column Connections for Steel Eccentrically Braced Frames

本研究项目的目标是开发和验证用于钢偏心支撑框架的安全和经济的链柱连接。1994年的北岭地震和1995年的神户地震暴露了美国在钢弯矩框架连接的设计、细节和焊接实践方面的根本缺陷。然而，最近在这两个国家进行的研究在了解与钢结构弯矩连接相关的问题方面取得了重大进展。偏心支撑框架(EBF)为钢结构建筑提供了一种替代弯矩框架的抗侧力体系。EBF提供的更高的刚度可以提供比弯矩框架更重要的优点，EBF的使用自北岭地震以来就开始使用，许多使用EBF连接到柱的配置。这种体系中的链柱节点对框架的抗震性能和安全性起着至关重要的作用。在北岭地震中，导致弯矩框架节点性能不佳的许多焊接和设计条件也存在于EBF链柱节点中。同时，杆柱节点的受力和弹塑性变形要求明显大于弯矩框架节点。然而，到目前为止，几乎没有任何研究针对EBF中的链接到列的连接。然而，在西海岸的主要建筑项目中，EBF的施工正在进行中，使用的连接细节有问题，尚未经过试验验证。将对抗震钢EBF的链柱连接进行分析和大规模试验研究相结合的计划。将使用非弹性有限元研究来研究和改进各种有希望的连接细节。然后，将使用全尺寸循环载荷试验来评估连接性能，然后制定设计建议。该项目将与日本京都大学的研究人员密切合作进行。计划中的合作包括美国和日本双方之间的协调实验调查，京都大学的一名博士生参与美国方面的研究，京都大学使用美国没有的加载设备对在美国制造的标本进行动态测试。这个项目还将包括与台湾国家地震工程研究中心的额外合作。这个项目是在NSF 98-36下的第三年竞争中得到支持的。《美日城市防震减灾合作研究》

0000031EngelhardtThe objective of this research project is to develop and validate safe and economical link-to-column connections for use in steel eccentrically braced frames.The 1994 Northridge and 1995 Kobe earthquake exposed fundamental deficiencies in US design, detailing and welding practices for connections in steel moment frames. Recent research conducted in both countries, however, has lead to major strides in understanding the problems associated with steel moment connections.Eccentrically braced frames (EBFs) provide an alternative to moment frame as a lateral force resisting system in steel buildings. The higher stiffness provided by an EBF could offer important advantages over a moment frame, and the use of EBFs have been constructed since the Northridge Earthquake, many using a configuration where the EBF link is attached to the column. The link-to-column connection in such systems plays a critical role in the seismic performance and safety of the frame.Many of the welding and design conditions responsible for the poor performance of moment frame connections in the Northridge Earthquake are also present in EBF link-to-column connections. At the same time, the force and inelastic deformation demands at link-to-column connections are substantially greater than at moment frame connections. However, virtually no research effort has been directed towards link-to-column connections in EBF to date. Nonetheless, EBF construction is proceeding on he West Coast for major building projects using questionable connection details that have not been verified by testing.A program of combined analytical and large-scale experimental studies will be conducted on link-to-column connections for seismic-resistant steel EBFs. A variety of promising connection details will be investigated and refined using inelastic finite element studies. Connection performance will then be evaluated using full-scale cyclic loading tests, followed by the development of design recommendations.This project will be conducted in close collaboration with investigators at Kyoto University in Japan. The planned collaboration includes coordinated experimental investigations between the US and Japanese sides, participation of a doctoral student from Kyoto University in the US side research, an dynamic testing of specimens fabricated in the US at Kyoto University using loading equipment not available in the US. This project will also include additional collaboration with the National Center for Research in Earthquake Engineering in Taiwan.This project is supported under the 3rd-year competition under NSF 98-36. "US Japan Cooperative Research in Urban Earthquake Disaster Mitigation."