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采用钢筋网片约束局压区核心混凝土可改善其延性,提高局压承载力。以局压面积比A b/A l、约束面积比A cor/A l以及钢筋网片体积配筋率ρv为主要参数,进行钢筋网片约束预留孔道活性粉末混凝土轴心局压试验,研究局压破坏形态、裂缝发展模式、局压楔形体特征、局部荷载与局压变形关系以及局压承载力。试验结果表明:当A cor/A l不小于1时,局压区网片钢筋能达到屈服,钢筋网片对核心活性粉末混凝土的约束作用显著;试件的初裂荷载较小,开裂后至破坏前表面裂缝发展缓慢,破坏时承压面附近混凝土局部剥落,但试件相对完整;局压破坏可划分为压密、楔形体形成、楔形体滑移、破坏4个阶段。分析A cor/A l、A b/A l、ρv对局压承载力提高系数的影响,结合未配筋局压试验结果,提出钢筋网片约束活性粉末混凝土局压承载力实用计算式,计算值与实测值吻合较好。
The use of steel mesh restraint pressure zone core concrete can improve its ductility and increase the pressure bearing capacity. Taking the area pressure ratio A b / A l, the confinement area ratio A cor / A l and the volumetric reinforcement ratio ρv of the steel mesh as the main parameters, axial compression tests of preactivated activated carbon concrete The pattern of local pressure failure, the mode of fracture development, the characteristics of the wedge body under local pressure, the relationship between local load and partial pressure and the bearing capacity of partial pressure. The test results show that when A cor / Al is not less than 1, the rebars of the rebar mesh can achieve yielding, and the restraint effect of the rebar mesh on the core reactive powder concrete is remarkable. The initial cracking load of the specimen is small, Before the failure, the surface cracks develop slowly. When the concrete is damaged, the concrete spalling partially occurs near the pressure bearing surface, but the specimen is relatively intact. The partial pressure failure can be divided into four stages: compactness, wedge formation, wedge sliding and destruction. The influence of A cor / A l, A b / A l, ρv on the coefficient of increase of bearing capacity was analyzed. According to the results of partial pressure test, the practical calculation formula of bearing capacity of confined activated powder concrete with reinforced mesh was proposed. The value is in good agreement with the measured value.