NIST logo

Publication Citation: Retrofit of Pre-Northridge Moment-Resisting Connections

NIST Authors in Bold

Author(s): S A. Civjan; M D. Engelhardt; John L. Gross;
Title: Retrofit of Pre-Northridge Moment-Resisting Connections
Published: April 01, 2000
Abstract: An experimental program was undertaken to evaluate methods to retrofit existing steel moment connections for improved seismic performance. Six full-scale subassemblages were tested under cyclic loading. Typical pre-Northridge connections were retrofit by the addition of either a bottom flange dogbone or a welded bottom flange haunch. Retrofitted specimens were tested both with and without a composite floor slab. The tests showed poor performance of the bottom flange dogbone retrofit when the existing low toughness welds were left in place. Somewhat improved performance was observed when the bottom flange dogbone was combined with replacement of beam flange groove welds with higher toughness welds. The welded bottom haunch retrofit showed excellent performance on specimens with a composite slab, even though the existing low toughness beam flange groove welds were left in place. The presence of the composite slab appeared to help prevent fracture of the existing top flange weld in the haunch retrofit. This paper provides a summary of the complete experimental program.
Citation: Journal of Structural Engineering-ASCE
Volume: 126
Issue: No. 4
Pages: pp. 445 - 452
Keywords: building technology;seismic rehabilitation;steel moment connection;steel moment connection retrofit;welded bottom haunch
Research Areas: Building and Fire Research
PDF version: PDF Document Click here to retrieve PDF version of paper (480KB)