【摘要】 通过6片无粘结部分预应力混凝土梁和1片普通钢筋混凝土梁的疲劳试验,研究了这种结构的疲劳破坏形态以及刚度、钢筋应变、混凝土应变随着重复荷载次数的变化规律。研究表明:无粘结部分预应力混凝土梁的疲劳破坏主要是梁内受拉普通钢筋的疲劳断裂引起的,预应力钢筋和受压区混凝土的应力幅较低,一般不会发生疲劳破坏;荷载重复200×104次后,无粘结部分预应力混凝土梁刚度退化明显。文中还给出了无粘结部分预应力混凝土梁疲劳寿命的计算方法,所得计算值与试验值吻合较好。更多还原

【Abstract】 Based on the test of a total of 7 concrete model beams,either RC or UPC,the development of failure patterns,the beam rigidity and the strain variation of reinforce and concrete with the cycle frequency of increasing fatigue were studied.Test results indicate that the fatigue failure is caused mainly by the fatigue fracture of non-prestressed steel bar.There was no fatigue failure found in the prestressed steel bar and compressive zone concrete because of the low stress amplitudes in them.After 2 million fatigue circles,the stiffness of UPC beams degenerated obviously.Calculated from the method of the predicting fatigue life of UPC beams proposed in the paper are in good agreement with the test results.更多还原