高性能混凝土简支梁正截面的抗弯疲劳性能

Bending Fatigue Behavior of High-performance Concrete Simply-supported Beams

通过10根三分点加载方式下的简支梁抗弯静力和疲劳试验,研究了不同混凝土强度等级、不同钢筋类型和不同荷载水平对高性能混凝土梁正截面疲劳性能的影响。通过分析梁跨中挠度、压区混凝土应变和拉区钢筋应变以及梁裂缝的发展规律,考察了高性能混凝土梁在弯曲重复荷载作用下的疲劳损伤过程。结合高性能混凝土和钢筋的材料疲劳损伤分析,提出了高性能混凝土梁疲劳寿命方程和疲劳后梁挠度的计算公式,并将理论计算的疲劳寿命、挠度与试验结果进行了比较,最后对比分析了高性能混凝土梁与普通混凝土梁抗弯疲劳性能的差异。

Based on the static and fatigue bending tests of 10 simply-supported beams under threepoint loading, the strength grade of concrete, two types of steel bars and different load levels were studied for the fatigue behavior of high-performance concrete beams. Through analyzing the mid-span deflection of beams, strains of concrete in compressive zone and strains of steel bars in tensile zone, as well as crack development regularity of the beams, the fatigue damage process of high-performance concrete beams under flexural repeated loading were observed. The equation of fatigue life and deflection calculation formula of beams after fatigue loading of high-performance concrete beams were put forward by combining the fatigue damage analysis of materials both for high-performance concrete and steel bars. Meanwhile, theoretical fatigue life and deflection were compared with test ones. Finally, the difference between bending fatigue behavior of high-performance concrete beams and that of normal strength concrete beams was comparatively analyzed.