Title:
Impact of Confinement on Bar Anchorage in Relocated Plastic Hinges
Author(s):
Taylor J. Brodbeck, Zachary A. Shurow, Rudolf Seracino, and Mervyn J. Kowalsky
Publication:
Structural Journal
Volume:
121
Issue:
3
Appears on pages(s):
57-68
Keywords:
performance-based design; reinforced concrete (RC); repair and strengthening; seismic design
DOI:
10.14359/51740459
Date:
5/1/2024
Abstract:
Bridges subjected to extreme damage from earthquakes are usually
considered unrepairable, and therefore must be replaced. One
location where damage is concentrated in reinforced concrete
bridges is in the plastic hinges that form at the ends of columns
where the moment demand is the largest, causing buckling or fracture of the reinforcement. Recent studies have shown that plastic hinge relocation can restore reinforced concrete columns to their original force and displacement capacities. In this repair, a plastic hinge damaged by a seismic event is strengthened so that in subsequent seismic events, damage will form in an undamaged section, ensuring a ductile response. The aim of this research is to improve the constructability and performance of the repair using a steel jacket. Tests were conducted on columns subjected to reversed
cyclic loading, repaired, and retested. A bolted connection simplified
construction. Research has shown that the repair’s response is
weakened when fractured bars in the original plastic hinge debond.
In these tests, anchorage and bond conditions were improved by
increasing the confining stresses by using a larger jacket thickness.
This enhanced the seismic resilience, evident by an increase in
dissipation of energy and reduction in strength degradation.