疲劳荷载下钢纤维高强混凝土梁裂缝宽度的计算方法

Calculating method for crack width of steel fiber reinforced high-strength concrete beams under fatigue loads

通过8根钢纤维高强混凝土梁的疲劳试验,分析钢纤维体积率、钢纤维类型和钢纤维掺入层厚对钢纤维高强混凝土梁裂缝宽度和裂缝间距的影响。结果表明,在高强混凝土梁中掺加钢纤维能有效限制裂缝的发展,静载作用下,掺入钢纤维的高强混凝土梁裂缝宽度减小39%～133%;疲劳荷载作用下,裂缝宽度减小35%～121%,裂缝间距减小28%～67%。最后探讨静载及疲劳荷载作用下钢纤维高强混凝土梁裂缝宽度的计算方法,结合试验数据提出疲劳荷载作用下钢纤维高强混凝土梁裂缝宽度的计算公式。

Abstract： Based on the fatigue test results of 8 steel fiber reinforced high-strength concrete beams, the influencing factors, such as the steel fiber volume ratio, steel fiber type and depth of the steel fiber covering in the beams on crack width and crack spacing are studied. The results show that steel fibers added into the high-strength concrete beams can prevent the development of the fatigue crack and to reduce crack width and crack spacing effectively. Compared with those non fiber reinforced beams crack widths of steel fiber reinforced high-strength concrete beams decrease 39% 133% under static load. Fatigue crack widths decrease 35% - 121% and the crack spacings decrease 28% -67%. Finally, the crack width evaluation method under static and fatigue loads is discussed, and the formulas of crack width of steel fiber reinforced high-strength concrete beams under fatigue loads are proposed.