Thin Steel Sheet Wrapping on RC Columns and Steel Plate Strengthening on Beam-Column Joints for Seismic Ductility and Capacity Improvements


Two 4/5-scale reinforced concrete beam-column assemblages were tested under cyclic loading to study the limit states of bridge substructures and the performance of a new lightweight steel wrapping technology for the seismic retrofit of columns. The first specimen was unretrofitted and served as a benchmark. The circular column of the second specimen was wrapped with a thin steel sheet whose ends were connected with an interlocked nail joint. The bent cap/column joint of the second specimen was strengthened with a steel cage welded together from several steel plates. Test results indicated that the unretrofitted specimen failed in column shear at displacement ductility of 2.0-2.5. The repaired first specimen then failed in column longitudinal rebar pullout from the bent cap/column joint at displacement ductility of 3.0-4.0. The new retrofit technique has enabled the displacement ductility to increase to 6.0-8.0 before the column rebar was pulled out of the joint due to significant shear cracks.

Meeting Name

100th Anniversary Earthquake Conference


Civil, Architectural and Environmental Engineering

Keywords and Phrases

Beam-Columns; Ductility; Reinforced Concrete; Reinforcing Steels; Retrofitting; Seismic Phenomena; Sheet Metal

Document Type

Article - Conference proceedings

Document Version


File Type





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