摘要
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 concrete which is confined by the orthogonal ties has relatively large ductility and high bearing strength. The reactive powder concrete （RPC） block reinforced by the orthogonal ties was used to simulate the anchorage zone concentratedly loaded by post-tensioned tendons. Considering three parameters, i.e. the ratio of the net area of the concrete supporting the plate to the area of the bearing plate Ah/Al , the ratio of the area of the bearing plate to the area of core concrete Acor/At , and the ratio of reinforcement Pv , twelve specimens were built and loaded monotonically to failure. The failure mode, cracking propagation, local wedge, relationship between local pressure and deformation, and local bearing capacity were investigated. The experimental results show that, the confinement effect is obvious, i.e. the ties yielded, when the ratio Acor/Al exceeded 1. The specimens crack under small load. Prior to failure, finite cracks of side surface developed slowly. Large width cracks and chip off-falling occur on the loading ends, but the specimens wholly keep entirety. The specimen failure may be divided into four stages, including consolidation, forming wedge, slippage of wedge, and failure. Three major parameters including AcoJAz, Ab/At, and Pv , which influence the local bearing strength factor, were analyzed. Combined with experimental results of RPC without reinforcement, a calculation method is proposed for the bearing strength of the reactive powder concrete reinforced with orthogonal ties. The calculation values show a good agreement with the test results.
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2013年第11期141-150,共10页
Journal of Building Structures
基金
黑龙江省自然科学基金项目(E200835)
教育部长江学者奖励计划项目(2009-37)
哈尔滨工业大学"985"工程优秀科技创新团队建设项目(2011)
黑龙江省科技计划项目(GC09C205
TC10A0101)
关键词
活性粉末混凝土
局部受压
钢筋网片
静力试验
承载力
reactive powder concrete
local pressure
orthogonal ties
static test
bearing capacity
