江阴大桥节段式钢箱梁的疲劳性能研究

Study on the Fatigue Properties of Sectional Steel Box Girder in JiangYin Bridge

针对一些现役钢箱梁桥梁上发现的病害,以江阴大桥钢箱梁焊接细节为研究对象,设计了节段式钢箱梁焊接细节模拟试件,研究了该试件在疲劳荷载作用下的疲劳性能。研究显示,在疲劳试验开始前,试件上的测点a^f在25kN静荷载作用下的应力值分别为255.57、261.50、221.34、224.39、167.11和177.71MPa;在加载上/下限值为25kN/5kN、频率为3Hz的疲劳荷载后,试件从产生肉眼可见的裂纹到破坏需要0.57万次;基于残余应变的累计损伤公式可以较好地反映该试件的损失发展过程。

Owning to some disease found in the active steel box girder bridge, this paper takes the JiangYin bridge steel box girder welding details as sample, and designs the specimen about the details welding of sectional steel box girder, which is studied with the fatigue properties in the fatigue load level 5 kN/25 kN and fatigue frequency 3 Hz. The results show that the stress of the measuring point a in 25 kN is 255.57 MPa before the fatigue test, so b is 261.50 MPa, c is 221.34 MPa, d is 224.39 MPa, e is 167.11 MPa and f is 177.71 MPa; The steel box girder specimens producing visible cracks to destroy needs 5 700 times; Formula which is based on the cumulative damage can better reflect the test steel box girder damage development process of specimen.