钢桥面沥青混合料铺装体系疲劳特性的损伤力学分析

用损伤力学原理及方法,从力学近似法角度分析了单纯的沥青混合料铺装层矩形截面梁疲劳损伤特性,推导出梁的应变场和疲劳寿命预测公式。按抗弯刚度等效简化原则,将疲劳试验复合梁模型中的实际桥面用钢板简化为沥青混合料铺装层叠加到下面的沥青混合料铺装层上,共同组成准单纯的沥青混合料铺装层矩形截面梁,应用该原理及方法推导出梁底缘的应变场,以南京长江第二大桥钢桥面环氧沥青混凝土铺装体系复合梁疲劳试验为例,进一步推导出复合梁的疲劳寿命预测公式。通过实例分析,表明损伤力学原理及方法可用于分析钢桥面沥青混合料铺装体系疲劳特性,其疲劳寿命预测结果是较为精确的,它的实际应用还需给出相应的修正,此外指出了环氧沥青混凝土铺装具有很好的抗疲劳性能。

Damage mechanics on the fatigue characteristics of asphalt mixture surfacing for steel bridge decks

The fatigue damage characteristics of beams with rectangular cross sections for simple asphalt mixture surfacing is analyzed by using the method of damage mechanics.From the method,the strain field in the beam and a formula for predicting the fatigue life of the beam are presented.According to the principle of bending-resistance stiffness equivalence,the steel bridge deck of the composite beam model for fatigue tests is simplified into an asphalt mixture surface overlay on the original asphalt mixture surfacing,and the strain in the beam for the quasi-simple asphalt mixture surfacing is derived.As an example,using the composite beam fatigue test on the steel bridge deck epoxy asphalt concrete surfacing of Nanjing Second Yangtze River Bridge,a predictive formula for the fatigue life of the beam is proposed.The results indicate that the damage mechanics principle and the associated method are useful for the analysis of the fatigue damage of steel bridge deck asphalt mixture surfacing,and the prediction of fatigue life is quite reliable.Furthermore,it is suggested that epoxy asphalt surfacing appears to provide good fatigue-resistance.