预应力钢纤维混凝土板弯曲疲劳挠度试验研究

抗疲劳性能是结构及构件的重要性能指标之一,本文通过弯曲疲劳试验对3种钢纤维体积率(0%、1%、2%)的预应力钢纤维混凝土板在不同应力水平(0.75、0.80、0.85)下的弯曲疲劳挠度变化规律以及疲劳损伤特性进行了研究,得到了不同钢纤维体积率及不同应力水平下预应力钢纤维混凝土板的跨中挠度曲线,揭示了预应力钢纤维混凝土板的跨中挠度在疲劳过程中呈现3阶段分布并且在循环第Ⅱ阶段呈线性,疲劳破坏时板的挠度约为其初始挠度的2.4倍的规律。在此基础之上,根据M iner线性累积损伤理论建立了疲劳寿命预测模型,用该模型预测得出的疲劳寿命与实测寿命在3倍离散范围内。

Experimental investigation of fatigue deflection of steel fiber reinforced prestressed concrete slab

Fatigue resistance is one of the important characteristics of structures and structural components.In this paper the law of fatigue deflection and the characteristics of fatigue damage of Steel Fiber Reinforced Prestressed Concrete Slab(SFRPCS)(0%、1%、2%) under different stress level(0.75、0.80、0.85) are investigated through flexural fatigue experiment.Two kinds of deflection curves are obtained.These curves show that the deflection development of SFRPCS can be divided into three stages and the second stage is nearly linear.The ultimate deflection is about 2.4 times more than the initial value.A model of fatigue-life prediction is proposed according to Miner linear cumulative damage theory.Compared with the experimental fatigue-life,the predictive-life is within three times by using the proposed model.