ICR treatment experiment for fatigue cracks of orthotropic steel bridge deck

WANG Qiudong;JI Bohai;YUANZHOU Zhiyuan;YE Zhi;FU Zhongqiu;College of Civil and Transportation Engineering,Hohai University;

orthotropic steel bridge deck;;fatigue crack;;impact crack-closure retrofit;;extension section;;extension life;;plastic deformation

Three local full-scale specimens with fatigue cracks on weld root of ICR-1,ICR-2 and DB-1 were investigated for the deck-U rib weld of orthotropic steel bridge deck. The fatigue loading after impact crack-closure retrofit treatment(ICR treatment) was conducted on ICR-1 and ICR-2. The half fatigue cracks were processed by ICR treatment,and the specimen was cut along the direction vertical to crack propagation to obtain the initial crack section and the section after treatment. The treatment depth and the superficial tissue were analyzed by the metalloscope. The results show that the propagation life of initial cracks is sharply increased after ICR processing. New fatigue cracks generate in both sides of areas processed by ICR,and the propagation life of new cracks is greater than that of initial cracks. The initial cracks are closed well and bear force with base metal as a whole structure after ICR treatment. The ICR treatment can lead to apparent plastic flow of superficial base metal,where the compression generates towards the weld root and deck thickness.