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使用超高韧性水泥基复合材料(Ultra High Toughness Cementitious Composite,简称UHTCC)取代普通混凝土可以有效控制裂缝宽度,阻止外界不利因素进入混凝土和钢筋,极大降低钢筋腐蚀的可能性,从而可以显著提高钢筋混凝土结构耐久性。UHTCC是在单轴拉伸状态下具有应变硬化特性的超高韧性材料,能够稳定地分担部分拉力。为了对钢筋增强超高韧性水泥基复合材料受弯结构构件进行更加合理的设计以节约钢材,在设计中应该考虑受拉区UHTCC拉伸承载能力。开展了钢筋增强超高韧性水泥基复合材料受弯构件的研究工作,先后完成了受弯理论分析、无腹筋长梁实验研究、试验研究与理论分析验证对比、裂缝控制分析、承载力简化计算方法等方面研究。该文依据UHTCC单轴拉伸状态下的应变硬化特性、单轴压缩状态的双直线模型以及平截面假定,进行了钢筋增强超高韧性水泥基复合材料受弯构件的理论分析,包括正截面受弯各阶段内力分析、界限配筋梁受压区高度的确定、加载至破坏整个过程的弯矩-曲率关系的确定以及跨中挠度的计算。
Replacing common concrete with ultra-high toughness cementitious composite (UHTCC) can effectively control the width of cracks and prevent external unfavorable factors from entering concrete and reinforcing steel bars, and greatly reduce the possibility of corrosion of reinforcing steel bars, thereby significantly increasing the reinforcing steel bar Concrete structure durability. UHTCC is an ultra-tough material with strain hardening properties in a uniaxially stretched state, and can stably share part of the tension. In order to make more reasonable design of the flexural structural members reinforced with ultra-high toughness reinforced steel to save the steel, the tensile bearing capacity of the UHTCC in the tensioned zone should be considered in the design. Carried out research on flexural members reinforced with ultra-high toughness reinforced cement-based composites, and completed the bending theory analysis, the experimental study without web reinforcement beams, the contrast between experimental and theoretical analysis, the analysis of crack control and the simplified calculation method of bearing capacity Other aspects of research. According to the strain hardening characteristics under uniaxial tension of UHTCC, the bilinear model of uniaxial compression and the assumption of flat section, the theoretical analysis of flexural members reinforced with ultra-high toughness reinforced cement-based composites is carried out, The internal force analysis of each stage of the bend, the determination of the height of the compression zone of the bounding reinforcement beam, the determination of the moment-curvature relationship from loading to failure of the entire process, and the calculation of the mid-span deflection.