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具有超高韧性新型随机PVA短纤维增强的水泥基复合材料(UHTCC)代替传统的具有准脆性应力软化特征的混凝土或纤维混凝土材料制作的钢筋(RUHTCC)受弯梁,可提高承载力,改善构件的延性,并具有良好的损伤演变能力,被认为是一种抗震性能较好的新型构件形式。除了配筋率和UHTCC拉压材料性能外,截面几何尺寸是影响其弯曲性能的一个重要因素。基于受弯理论分析和试验验证,采用该理论公式对截面几何尺寸(截面高度、宽度以及面积)的影响规律进行了系列分析。结果发现:对承载力,梁高度比宽度影响明显,而对承载力提高幅度和变形而言,随梁高的增加而减小,梁宽没有影响;对裂缝控制来说,只要梁下边缘的极限拉应变小于UHTCC材料的极限拉应变,截面尺寸的变化几乎不影响裂缝宽度的大小。并进一步针对RUHTCC梁的受弯设计提出了一些设计建议。
Reinforcing bars (RUHTCC) made of concrete or fiber reinforced concrete (SRHTCC) with traditional ultra-brittle stress-softening properties with ultra-high toughness, new random PVA short fiber reinforced cementitious matrix composites (UHTCC) increase bearing capacity and improve the performance of components Of the ductility, and has a good ability to damage evolution, is considered a better seismic performance of a new component form. In addition to the reinforcement ratio and the tensile properties of UHTCC materials, the cross-sectional geometry is an important factor affecting the flexural properties. Based on the theoretical analysis and experimental verification of bending, the influence of the theoretical formula on the geometric dimensions (section height, width and area) was analyzed serially. The results show that: the bearing capacity, the beam height significantly affected the width, while the bearing capacity of the increase and deformation, with the increase of the beam height decreases, the beam width has no effect; for the crack control, as long as the lower edge of the beam The ultimate tensile strain is less than the ultimate tensile strain of the UHTCC material and the change in cross-sectional dimension has little effect on the width of the crack. And some design suggestions are put forward for the bending design of RUHTCC beams.