Retrofit of Pre-Northridge Moment-Resisting Connections

Published

April 1, 2000

Author(s)

S A. Civjan, M D. Engelhardt, John L. Gross

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

Pub Type

Journals

Download Paper

Local Download

Keywords

building technology, seismic rehabilitation, steel moment connection, steel moment connection retrofit, welded bottom haunch

Citation

Civjan, S. , Engelhardt, M. and Gross, J. (2000), Retrofit of Pre-Northridge Moment-Resisting Connections, Journal of Structural Engineering-ASCE, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=860340 (Accessed October 11, 2025)