问题的提出及国内外概况“PC~*梁正截面疲劳开裂的试验研究”是在制定规范中提出的课题,目的是要从试验和理论上搞清疲劳开裂的问题,为工程设计提供依据。目前,国内外有关规范都按经典的弹性公式计算疲劳开裂。至于真正的疲劳开裂极限状态并不很清楚。国内没有专门的试验。国外由于试验简单, The introduction of the problem and the domestic and international survey “PC~* Experimental Research on the Fatigue Cracking of Liangzheng Section” is a topic proposed in the formulation of the specification. The purpose is to find out the problem of fatigue cracking both experimentally and theoretically and provide a basis for engineering design. At present, fatigue cracking is calculated according to the classical elastic formulae at home and abroad. As for the true fatigue cracking limit state, it is not very clear. There is no special test in the country. Due to the simple test abroad,