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http://dx.doi.org/10.7781/kjoss.2017.29.1.025

Seismic Retrofit of Welded Steel Moment Connections Considering the Presence of Composite Floor Slabs  

Lee, Cheol Ho (Dept. of Architecture and Architectural Engineering, Seoul National University)
Kim, Sung Yong (Dept. of Architecture and Architectural Engineering, Seoul National University)
Publication Information
Journal of Korean Society of Steel Construction / v.29, no.1, 2017 , pp. 25-36 More about this Journal
Abstract
In the 1994 Northridge earthquake, connection damage initiated from the beam bottom flange was prevalent. The presence of a concrete slab and resulting composite action was speculated as one of the critical causes of the prevalent bottom flange fracture. In this study, four seismic retrofit schemes are proposed in order to salvage welded steel moment connections with composite floor slabs in existing steel moment frames. Because top flange modification of existing beams is not feasible due to the presence of a concrete floor slab, three schemes of bottom flange modification by using welded triangular or straight haunches or RBS(reduced beam section), and beam web strengthening by attaching heavy shear tab were cyclically tested and analyzed. Test results of this study show that haunch and web-strengthened specimens can eliminate the detrimental effect caused by composite action and ensure excellent connection plastic rotation exceeding 5% rad. Design recommendations for each retrofit scheme together with supplemental numerical studies are also presented.
Keywords
Seismic retrofit; Welded steel moment connection; Slab effect; Heavy shear tab; Haunch; Reduced beam section(RBS);
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
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