Title:
Effectiveness of Carbon Fiber-Reinforced Polymer Sheets for Torsional Strengthening of Reinforced Concrete Beams
Author(s):
Yail J. Kim and Abdulaziz Alqurashi
Publication:
Structural Journal
Volume:
121
Issue:
5
Appears on pages(s):
203-215
Keywords:
carbon fiber-reinforced polymer (CFRP); rehabilitation; strengthening; torsion
DOI:
10.14359/51740867
Date:
9/1/2024
Abstract:
This paper presents the torsional behavior of reinforced concrete
beams strengthened with carbon fiber-reinforced polymer (CFRP)
sheets. Assorted retrofit schemes are implemented with variable
widths and number of single- and double-layer CFRP U-wraps.
After loading 27 beams (three unstrengthened and 24 strengthened), test data were collected to investigate the efficacy of those U-wrap configurations. The width and layer of the bonded sheets dominate the capacity of the beams, whereas the number of the U-wraps in the longitudinal direction is an insignificant attribute. Although the CFRP retrofit decreases structural ductility, the placement of the U-wraps impedes stiffness-reduction rates, reduces twist angles, and redistributes torque-induced stresses. The identified characteristic effective shear modulus of the strengthened
beams demarcates the pattern of energy drops, which are related
to the degree of brittleness in failure. As far as effective strains
are concerned, the applicability of existing equations is appraised,
and a new expression is proposed through reliability theory and
stochastic simulations.