Title:
Seismic Retrofitting of Corroded Reinforced Concrete Columns Using Ultra-High-Performance Concrete Jacketing
Author(s):
Nicolas El-Joukhadar and S. J. Pantazopoulou
Publication:
Structural Journal
Volume:
121
Issue:
4
Appears on pages(s):
87-99
Keywords:
corrosion damage; durability; old construction; rehabilitation; reinforcement corrosion; seismic retrofit; ultra-high-performance concrete (UHPC) jacketing.
DOI:
10.14359/51740572
Date:
7/1/2024
Abstract:
This paper investigates the efficacy of ultra-high-performance
concrete (UHPC) jacketing as an option for seismic retrofit
(repair or strengthening) of structural components that have been
damaged by reinforcement corrosion. Previous work has illustrated
that UHPC cover fully mitigates corrosion in the absence
of service cracks and significantly reduces the corrosion rate in the
case of preexisting cracks. In the present experimental study, cover
replacement by UHPC is used to repair and strengthen corroded
columns. Six lap-spliced columns designed based on pre-1970s
design standards were constructed and subjected to artificial corrosion. Parameters of the investigation were: a) the aspect ratio of the specimens; b) the bar size (to account for the effect of bar diameter loss on bond); and c) the condition of the specimen (repair or strengthening after damage due to application of simulated seismic load to assess the effectiveness of retrofitting corroded components, even after having endured earthquake damage). The results show that thin UHPC jackets replacing conventional concrete cover suffice to impart a significant increase in strength and ductility of the columns. The jackets also endow the corroded and unconfined
lap splices with significant force and deformation development
capacity, thus alleviating a source of excessive column flexibility
in existing construction.