Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Retrofit of Pre-Northridge Moment-Resisting Connections



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


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.
Journal of Structural Engineering-ASCE
No. 4


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


Civjan, S. , Engelhardt, M. and Gross, J. (2000), Retrofit of Pre-Northridge Moment-Resisting Connections, Journal of Structural Engineering-ASCE, [online], (Accessed July 23, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created March 31, 2000, Updated October 12, 2021