装配整体式双向密肋空心板疲劳性能分析

在总结归纳已有结构板疲劳试验的基础上，对装配整体式双向密肋空心板的正截面疲劳性能进行了理论分析，提出了装配整体式双向密肋空心板正截面弯曲疲劳强度计算及验算公式，并通过肋梁下部钢筋疲劳应力幅计算值、实测值及规范限值来验证公式的可行性。计算了基于跨中挠度反算法的疲劳刚度，并与试验数据进行对比，分析了板件疲劳后刚度退化规律。通过对预制底板钢筋的疲劳应力幅值计算及验算结果分析，提出了多项设计加强措施。通过基于刚度退化的疲劳损伤定义，选取了符合刚度退化规律的函数形式，得到了可用于计算板件刚度退化程度的公式，给出了板件疲劳后刚度计算以及疲劳性能预测方法。结果表明:当板件疲劳后刚度退化到弹性刚度的20%时，板件即达到疲劳寿命，进入疲劳破坏阶段；当装配整体式双向密肋空心板用于需要考虑疲劳荷载作用结构时，可以保证该新型空心板结构整体疲劳性能；所得结论为该新型板在立体停车场、工业厂房楼板以及大跨组合桥面板等结构中的应用提供可靠依据。

Analysis on Fatigue Performance of Assembled Monolithic Hollow-ribbed Slabs

Based on the summarizing of existing structural slab fatigue test results, the theoretical research on normal section bending fatigue performance of traditional assembled monolithic hollow-ribbed slabs was carried out. The calculation and checking formulas for the bending fatigue strength of traditional assembled monolithic hollow-ribbed slabs were presented. The feasibility of the formulas was verified by the calculation of the fatigue stress amplitude, the measured values and the specification limits of the lower steel bars of the rib beam. The fatigue stiffness based on the inverse algorithm was calculated and compared with the test data, and the law of stiffness degradation after fatigue was analyzed. By analyzing the fatigue stress amplitude calculation of rebar in precast slab, improvement measures were proposed. Through the definition of fatigue damage based on stiffness degradation, a function form which conforms to the law of stiffness degradation was selected, and a formula could be used to calculate the degree of stiffness degradation of the plate. The calculation method of fatigue stiffness and the prediction method of the performance of fatigue based on the fatigue stiffness degradation were put forward. The results show that when the stiffness of the plate is reduced to 20% of the elastic stiffness after the fatigue of the plate, the fatigue life and the fatigue failure stage will be reached. When assembled monolithic hollow-ribbed slabs are used in structures under fatigue loading, the improvement measures can ensure the whole fatigue performances of structures. The study results provide a reliable basis for the application of the new floor in the construction of the multistory parking lot, industrial factory building and the composite bridge decks.