Seismic Behavior of the Welded-Flange-Plate Moment Connection to Built-up Battened Columns

Abstract

In this paper, the seismic behavior of the welded-flange-plate (WFP) moment connection for the I-shaped beams to the built-up battened columns is numerically studied and different modifications to the connection configuration are investigated. To fulfill this goal, a comprehensive parametric study is performed on several variations of WFP connection to the built-up columns while stiffened with vertically positioned ribs. The study reveals that the connection undergoes severe states of strain/strain concentration at the beam connecting end-plate that attaches the beam’s top and bottom flange connecting plates to the flanges of the built-up column, and the cyclic behavior of the connection quite noticeably deteriorates due to undesirable out-of-plane deformation of the end-plate having low to moderate thickness. Hence, three retrofitting methods are suggested to improve the seismic behavior of the WFP connection with an end plate including (1) insertion of trimmed rectangular continuity plates inside the panel zone, (2) welding the end-plate interior face to the column flanges, and (3) fastening the end-plate to column flange with a welded T-section profile. A parametric study on the modified specimens indicates that the proposed modifications could remove observed weaknesses from the behavior of the conventional connection successfully and upgrade its seismic performance to the extent of becoming a reasonably adequate candidate for usage in the seismically resistant intermediate and special steel moment frames.