Research On Some Issue Of Link-to-column Connection In Steel Eccentrically Braced Frames

As seismic-resistant steel building systems, eccentrically braced frames (EBFs) are a popular alternative to moment resisting frames (MRFs) and concentrically braced frames (CBFs), due to their ability to combine high lateral stiffness and excellent ductility. In some EBF configurations, the link located at the center of the beam, between two braces. In some EBF configurations, one end of the link is attached to a column.The widespread damage observed at welded beam-to-column moment connections in steel MRFs following the 1994 Northridge and 1995 Kobe raised broad concerns about the performance of welded steel frames in strong earthquakes, and motivated extensive research in the US, Japan, and elsewhere. However, much less attention has been given to link to column connections in EBFs. Prior to the Northridge Earthquake, EBF link-to-column connections were designed and constructed in a manner very similar to MRF moment connections, Link to column connections in EBF are therefore likely to share many of the same problems observed in Moment Frame connections. EBF link-to-column connections are experience different, and in some cases, significantly more severe forces and deformations than moment connections in MRFs. Therefore, the improved design, detailing, and construction procedures developed for moment connections since the Northridge Earthquake may not necessarily be applicable to EBF link-to-column connections. The primary content of this research were as follows:1. To summarize the new connections developed after Northridge earthquake in recent years.2. To summarizes the test of the link-to-column connections in EBFs, and evaluate the applicability of new connections developed after Northridge earthquake in EBs. Consider the end plate connections appear promising to be used in EBFs. 3. Applied nonlinear (material, geometry and contact) finite element method to analyze the behaviors of the connections for fist time by ANSYS Program .Contact problem between endplate and column flange surface, bolt nut and neighborhood plate, bolt shank and bolt hole are simulated really. To investigate influence of the thickness of the endplate on link and weld, At the same time also analysis mechanical performance of the various types of link4. Design and construction recommendations for seismic design are presented at last.