针对多轴复杂应力状态下的混凝土疲劳破坏问题,进行一系列定侧压下双轴疲劳破坏试验,包括定侧压下受压疲劳、纯拉疲劳和拉-压变号疲劳试验。通过对试验资料的分析,建立各种应力状态下的混凝土疲劳S-N关系曲线和双轴疲劳破坏准则。由各侧压级别下的S-N曲线得到混凝土在相应工况下的疲劳强度折减系数,并利用其对实际工程进行疲劳验算,计算结果显示混凝土多轴疲劳破坏准则能很好地弥补现行规范在疲劳验算中的不足,计算结果令人满意。
Fatigue tests of concrete have been conducted,with constant confining stress,under compressive,tensile and alternate tension-compression fatigue loadings.Based on the results of the experiments,the equations of S-N curves under certain lateral stress are established and fatigue failure criterions for different loading cases are proposed.According to the S-N curves,the fatigue reduction coefficients for different fatigue loadings are obtained.According to the fatigue failure criterion of concrete,calculation of an existing concrete structure under fatigue loading is successfully checked.