钢筋钢纤维混凝土裂缝宽度影响系数研究

【作者】 徐海岩； 王志杰； 周平； 赵启超； 李志业；

【机构】 西南交通大学交通隧道工程教育部重点实验室；

【摘要】 通过构件试验、数值试验及室内模型试验,得到钢筋钢纤维混凝土裂缝宽度影响系数随裂缝宽度的变化曲线,结合可靠度及概率论、通过数据分析得到钢筋钢纤维混凝土裂缝宽度影响系数值,进而求得钢筋钢纤维混凝土衬砌管片偏心受压状态下最大裂缝宽度,对其正常使用极限状态下的抗裂性进行分析。结果表明:①纯弯梁及偏压柱构件试验中,分别在构件开裂相对稳定的荷载区间45~80kN、150~235kN,相对于钢筋混凝土,钢筋钢纤维混凝土构件裂缝宽度降低比率分别由29.22%降至13.11%、由43.72%降至19.40%,计算得到钢筋钢纤维混凝土裂缝宽度影响系数均为0.42;②通过数值试验,分别建立5个模型,得到裂缝宽度影响系数随构件横截面宽度、高度及裂缝宽度的变化曲线,得出其随宽度及高度的增大而增大、随裂缝宽度的增大而减小,且减小至某一定值而不再变化;③通过钢筋钢纤维混凝土衬砌管片偏心受压足尺模型试验,将构件试验中所得裂缝宽度影响系数代入公式,在实测裂缝宽度0.2mm及0.3mm下计算得到衬砌管片的裂缝宽度,分析得出钢筋钢纤维混凝土衬砌管片在正常使用极限状态下抗裂性具有38.4%的安全储备。对比现行《纤维混凝土结构技术规程》CECS 38-2004中钢纤维混凝土裂缝宽度影响系数的取值0.35,本文所得结果对其进行了修正,研究结果可为钢筋钢纤维混凝土裂缝宽度影响系数的进一步研究提供借鉴。更多还原

【Abstract】 By means of the component test,numerical test and model test,getting curves of the influence factor of crack width of steel fiber reinforced concrete varying with crack width,combining the theory of reliability and probability,receiving the value of influence factor of crack width of steel fiber reinforced concrete through data analysis,calculating the maximum crack width of steel fiber reinforced concrete lining segments under eccentric compression,analyzing the crack resistance of steel fiber reinforced concrete lining segments under serviceability limit state.The result shows:(1) In the test of pure bending beam and bias short column,in the relatively stable load interval of 45~80 kN and 150~235 kN of component cracking,the crack width reduction ratio of reinforced steel fiber reinforced concrete members respectively decrease from 29.22%to 13.11%,from 43.72%to19.40%;Both of the values of crack width factor of steel fiber reinforced concrete are calculated to be 0.42;(2) Through the numerical experimentation,establishing 5 models respectively,getting curves of the influence factor of crack width of steel fiber reinforced concrete varying with the width and height of cross section and crack width,showing that it increases with the increase of width and height and decreases with the increase of crack width to a certain value without change;(3) Through the full-scale model test of steel fiber reinforced concrete lining segmentsunder eccentric compression,substituting the influence factor of crack width obtained in component test into formula,calculating the crack width of lining segments under the measured crack widths of 0.2 mm and 0.3 mm,concluding that the crack resistance of steel fiber reinforced concrete lining segments has 38.4%safety stock under serviceability limitstate.Compared with the existing technical specifications for fiber reinforced concrete structures CECS 38-2004,of which the influence factor of crack width of steel fiber reinforced concrete is determined by 0.35,the results obtained in this paper revise it and can provide references for further study on the influence factor of crack width of steel fiber reinforced concrete.更多还原