Full-scale test modules are prepared to examine the mechanical
performance of U- and V-shaped
connection nodes of longitudinally distributed reinforcement in prefabricated
reinforcement cage modules used in open-cut station
structures. Indoor tests on bending-shear and double-point bending provide data on bending moment, strain, and crack
development. The mechanical performance of U- and V-shaped lapped joints in prefabricated reinforcement cages of open-cut metro stations under pure bending and combined bending-shear loading conditions is investigated and compared with
continuous reinforcement joints as a benchmark. The experimental results reveal
the crack propagation patterns, material strain responses, and load-bearing characteristics of the different joint types. Key findings
are as follows: (1) Under the pure bending condition, continuous reinforcement
joints display ductile behavior, with a bending moment capacity increasing by
81.3% from crack onset (675 kN·m) to the ultimate state
(1 224 kN·m), accompanied by an ultimate deflection of
12.1 mm. V-shaped lapped joints reach 80.2% (982 kN·m) of the ultimate bending capacity of continuous joints and show a
comparable ultimate deflection of 11.94 mm. U-shaped
lapped joints exhibit brittle failure behavior, with only a 31.7% strength
increase (from 575 to 757 kN·m) and minimal deformation
prior to failure. (2) Under the combined bending-shear
loading condition, continuous joints maintain the highest ultimate bending
moment (1 275 kN·m) and stiffness control, with a
deflection of 7.5 mm. V-shaped joints complete full
deformation cycles, reaching an ultimate deflection of 13.17 mm and 77.3% of
the ultimate bending capacity of continuous joints. U-shaped joints experience early cracking at
775 kN·m, followed by strength stagnation, resulting in
a final deflection of 6.8 mm, equivalent to 54.7% of the continuous joints′ capacity. (3) Comprehensive comparative analysis demonstrates that
the V-shaped lapped joints exhibit significant
performance advantages over U-shaped joints, achieving
82% of the ultimate load-bearing capacity, 85% of the
ductility coefficient, and better failure control when compared to continuous
joints. Therefore, V-shaped lapped joints are
recommended as the preferred solution for connecting longitudinally distributed
bars in prefabricated reinforcement cages.
ZHANG Jianwei
,
ZHANG Peng
,
WANG Jiaqing
,
CUI Tao
,
CHEN Jian
,
XING Jianjun
,
XIE Tingwei
,
NIU Yuzhe
. Experimental Study on
Mechanical Properties of Lapped Joints for Distributed Reinforcement Bars in Prefabricated Steel Cages Used in Open-Cut Station[J]. Tunnel Construction, 2025
, 45(3)
: 521
-531
.
DOI: 10.3973/j.issn.2096-4498.2025.03.007
