摘要
通过12片预应力混凝土梁的疲劳试验,对预应力混凝土梁的疲劳破坏形态进行了研究,对疲劳加载过程中预应力混凝土梁跨中挠度和混凝土应变随重复荷载次数的变化规律进行了重点分析,建立了基于实测挠度、压应变和中和轴高度的预应力混凝土梁刚度退化模型。结果表明:疲劳上限值越大其刚度退化越明显,接近线性衰减;随着疲劳上限值的降低,刚度衰减出现明显的相对稳定过程;对于疲劳下限荷载相同的梁,动态割线刚度衰减曲线上终值基本相同,即非预应力筋发生疲劳断裂后梁体刚度还有48%～54%。
Based on fatigue tests of 12 PC beams, the evolution of fatigue failure pattern of PC beams is studied and regularities of mid-span deflection and strain of concrete of PC beams varying with times of fatigue repeated loading are emphatically analyzed, and two stiffness degradation models of PC beams based on measured deflection, compressive strain and neutral axis height of prestressed concrete are established. The results show that （1） the larger the upper limit of fatigue load, the more obvious the rigidity degradation, and the greater upper limut may lead to linear degradation; （2） there is a distinct relative stable process of stiffness degradation with the reduction of the upper limit; （3） the same lower limit of fatigue load may result in the same upper limit value in the dynamic secant stiffness attenuation curve, i. e. , the beam has a residual stiffness of 48% - 54% when the nonprestressing steel bar is fractured.
出处
《公路交通科技》
CAS
CSCD
北大核心
2013年第8期62-69,共8页
Journal of Highway and Transportation Research and Development
基金
国家高技术研究发展计划(八六三计划)项目(2009AA11Z101)
关键词
桥梁工程
刚度退化规律
疲劳重复荷载
预应力混凝土梁
挠度
中和轴
bridge engineering
stiffness degradation regularity
fatigue repeated load
PC beam
deflection
neutral axis
