Title:
Shear Behavior of Precast Concrete Box Culverts Reinforced with Glass Fiber-Reinforced Polymer Bars under Concentrated Load
Author(s):
Ahmed Elnady, Salaheldin Mousa, and Brahim Benmokrane
Publication:
Structural Journal
Volume:
121
Issue:
3
Appears on pages(s):
173-186
Keywords:
design codes; experimental and analytical studies; failure mode and cracking pattern; glass fiber-reinforced polymer (GFRP) reinforcement; load-deflection behavior; precast concrete box culverts (PCBCs); punching- shear resistance; reinforced concrete; st
DOI:
10.14359/51740488
Date:
5/1/2024
Abstract:
This research evaluated the structural behavior of precast concrete
box culverts (PCBCs) reinforced with glass fiber-reinforced
polymer (GFRP) bars, both experimentally and theoretically. Four
full-scale specimens with a span of 1500 mm (59.06 in.), a rise
of 1500 mm (59.06 in.), and a joint length of 1219 mm (48 in.)
were prepared, along with one specimen with a span of 1800 mm
(70.87 in.). Four specimens were reinforced with GFRP bars, and
one specimen with steel bars as a reference. The PCBCs were tested
up to failure under a concentrated load over a contact area of 250 x
600 mm (9.8 x 23.6 in.) on the top slab. The load plate simulated the
footprint of the truck wheel load (87.5 kN [19.67 kip] CL-625 truck)
according to the Canadian Highway Bridge Design Code. The
investigated test parameters were the longitudinal reinforcement
stiffness (GFRP versus steel), the longitudinal GFRP reinforcement
ratios, specimen clear span, and slab thickness. Two-way shear
failure was observed in all the tested specimens as a result of the
concentrated load acting on the top slab. The test results revealed
that increasing the longitudinal reinforcement ratio, as well as
increasing the top-slab thickness, resulted in higher load-carrying
capacity, lower deflection, and lower concrete and reinforcement
strains. The experimental shear strengths were compared to the
values predicted using current code provisions for two-way shear
resistance equations. The results show that the punching-shear
resistance equation in CSA S806-12 provided good yet conservative
predictions of the shear capacity of the PCBCs’ top slab. The Canadian
Highway Bridge Design Code does not provide an equation
for two-way shear design of FRP-reinforced concrete members.
The two-way shear equation available for steel-reinforced concrete
members was modified to take into account the characteristics of
FRP bars. The modified equation produced predictions consistent
with the experimental results. Moreover, the findings of this study
demonstrate the feasibility and effectiveness of using GFRP bars as
internal reinforcement for PCBCs as an alternative to steel bars.