预应力混凝土梁疲劳可靠性及尺寸效应试验研究

为研究预应力混凝土梁在承受疲劳荷载后的可靠性变化及尺寸效应产生的影响,现对3根不同尺寸的预应力混凝土简支梁开展疲劳试验,采集试验数据并运用已有的可靠性计算方法对试验梁的可靠性进行初步的验算,通过对比不同尺寸试验梁的疲劳数据得到尺寸效应对试件承载力等性能的影响,计算试件在不同疲劳次数后的可靠度并对比计算结果分析其可靠性变化。分析试验结果发现,随着疲劳次数的增加,试件的可靠性逐渐降低;受拉区混凝土和受拉钢筋的疲劳可靠性均低于受压区混凝土和受压钢筋;在相同的疲劳循环次数下,尺寸较小构件在相同疲劳次数下的可靠性更低。

Experimental Study on Fatigue Reliability and Size Effect of Prestressed Concrete Beams

In order to study fatigue reliability of prestressed concrete beams and the effect of size effect on it,fatigue test of two prestressed concrete beams were carried out,where sizes of the beams were different.The tests data were collected,and the fatigue reliability of the test beams by existing calculate methods.By comparing the test data of different prestressed concrete beams with different size,the effect of size effect on performance of the beams can be found.At the same time,the reliability of the beams after different fatigue times was calculated,and change of the fatigue reliability by comparing the results.Based on calculation and analysis of the fatigue test data,it can be found that with the increase of the number of fatigue process,the reliability of the test pieces were reduced.The reliability of the stretched area is lower than the compression area.Under the same fatigue cycles,the reliability of smaller test pieces is lower than the bigger ones.