为解决地下结构侧墙-底板节点钢筋间距较小、混凝土浇筑不密实等问题，提出钢筋桁架形式的2种模块化节点优化方案。为研究钢筋模块化节点与钢筋绑扎节点的力学性能及裂缝开展情况的差异性，设计3个几何相似比为1∶3的缩尺构件来进行静力单向加载试验。试验结果表明： 1）相同荷载作用下钢筋模块化节点与传统节点在变截面处受拉主筋应力基本一致，甚至更小，采用模块化钢筋节点配筋能达到与传统节点配筋一致的力学性能； 2）随着外荷载的增加，模块化钢筋节点与钢筋绑扎节点初始裂缝位置与裂缝宽度大致相同，即侧墙外侧出现初始裂缝，位置均出现在侧墙变截面处外侧，宽度均在0.05 mm左右； 3）节点最终裂缝扩展路径基本一致，侧墙、底板外侧最大裂缝宽度均在0.25 mm左右。
To address the problems of small reinforcement spacing
and poor concrete pouring in the sidewallfloor joints of underground
structures, two optimization schemes for modular reinforced joints in the form
of steel trusses are proposed. In this paper, three scaleddown members with a geometrically similar ratio of 1∶3 are designed to perform static unidirectional loading test to
study the differences in mechanical properties and crack development between
the modular reinforced joints and the reinforced binding joints. The test
results show the following: (1) Under the same load, the tensile stress of the
main reinforcement at the variable crosssection of the
reinforced modular joints and the traditional joints is basically the same, or
even smaller. The reinforced modular joints can achieve the same mechanical
properties as the traditional joints. (2) As the external load increases, the
initial crack location and crack width of the modular reinforced joints and the
reinforced binding joints are roughly the same, which means that the initial
cracks appear on the outside of the sidewall(all cracks), and the width sizes
are approximately 0.05 mm. (3) Eventually, the joints crack expansion paths are
basically the same, and the maximum crack widths on the sidewalls and the
outside of the floor are at approximately 0.25 mm.
