为验证明挖车站主体结构装配式钢筋笼模块纵向分布钢筋U形、V形连接节点力学性能，制作足尺试验模块，通过单点弯剪及双点纯弯室内试验，获得弯矩、应变、裂缝发育等试验结果。系统研究明挖车站装配式钢筋笼分布筋U形与V形搭接接头在纯弯及弯剪耦合工况下的力学性能，并以分布筋通长连接构件为基准开展对比分析。试验重点揭示不同连接方式的裂缝发展规律、材料应变响应及承载特性。结果表明： 1)在纯弯工况下，分布筋通长连接构件呈现典型延性特征，其弯矩承载力从开裂阶段（675
kN·m）至极限状态（1 224 kN·m）提升81.3%，极限挠度达12.1
mm。V形搭接构件极限承载力为分布筋通长连接的80.2%（982 kN·m），极限挠度达11.94
mm； 而U形搭接构件表现为脆性破坏模式，性能增幅仅31.7%（由575 kN·m提升至757 kN·m），破坏前无显著变形。2）在弯剪复合工况下，通长连接构件保持最高极限弯矩（1 275 kN·m）与刚度控制能力（挠度7.5 mm）； V形搭接构件完成完整变形历程（极限挠度13.17 mm），极限弯矩为通长连接的77.3%； U形搭接构件则因早期开裂（775 kN·m）导致承载力停滞，最终挠度（6.8 mm）仅为通长连接的54.7%。3）综合对比显示，V形搭接在极限承载力（通长连接的82%）、延性系数（通长连接的85%）及破坏可控性方面，较U形搭接具有显著优势，被推荐作为装配式钢筋笼分布筋纵向连接优先方案。
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.
