Extending Fatigue Life of Cracked Out-of-Plane Gusset by Icr Treatment

Abstract

(Former student of Nagoya University) (7-3-1 Hongo, Japan) Various types of fatigue cracks have been found in steel bridges. To maintain steel bridges, repair and retrofit methods of such fatigue cracks have been developed. The authors developed a technique which generates plastic deformation of steel surface near the crack in order to close crack opening by an impact air tool. This method is called Impact Crack Closure Retrofit treatment (ICR treatment). Plate bending fatigue tests of out-of-plane gusset specimens were carried out. Fatigue cracks at turn-around welds and those which have propagated 10 and 20 mm were ICR-treated. Fatigue test results showed significant improvement in the fatigue life of specimens due to ICR treatment.

The efficiency of HFMI treatment and TIG remelting for extending the fatigue life of existing welded structures

“…2. Moreover, test results of treated virgin specimens were extracted from [4], [6], [9], [12], [17] and [19]- [25] and included in the same figures (denoted by the black and orange data points).…”

Local stress variation in welded joints by ICR treatment

“…To date, several fatigue tests have been performed, which show better the fatigue performance improvement after ICR treatment [12][13][14]. However, the detail effects of ICR treatment are still not clear, especially the improvement to the local stress condition.…”