Title: Flexural strengthening of large-scale
reinforced concrete beams using
near-surface-mounted self-prestressed
iron-based shape-memory alloy strips
Date Published: November - December 2018
Volume: 63
Issue: 6
Page Numbers: 55 - 65
Authors: Raafat El-Hacha and Hothifa Rojob
https://doi.org/10.15554/pcij63.6-03
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Abstract
An experimental program was conducted to investigate
the performance of large-scale reinforced concrete
beams strengthened with near-surface-mounted
iron-based shape-memory alloy (Fe-SMA) strips.
Shape-memory alloys are a unique class of alloys
with the ability to undergo large deformations and
return to their original shape through stress removal by
unloading or heating. Four beams were tested in total,
including a control beam and three beams strengthened
with near-surface-mounted Fe-SMA strips. One beam
was strengthened with five nonactivated strips, and two
beams were strengthened with five and seven activated
Fe-SMA strips, respectively.
The results revealed the effectiveness of the strengthening
technique in enhancing the flexural performance
of the strengthened beams at the service and ultimate
load conditions. Furthermore, the strengthened beams
failed in a ductile failure mode by crushing of concrete
after yielding of the steel reinforcements and the
Fe-SMA strips, similar to the behavior of an underreinforced
concrete beam. The performance of the
strengthened beams was compared with similar beams
strengthened with prestressed, near-surface-mounted
carbon-fiber-reinforced polymer (CFRP) bars with
comparable prestressing forces. The comparison
revealed the superiority of the near-surface-mounted
Fe-SMA in maintaining the ductile behavior of the
beams compared with the brittle failure of near-surface-mounted
CFRP-strengthened beams.