Fatigue Testing and Finite Element Analysis of Bridge Welds Retrofitted by Ultrasonic Impact Treatment

Ultrasonic impact treatment (UIT) offers a promising means for addressing detected or anticipated fatigue problems in steel highway bridges. Although the beneficial effects of UIT are well documented, a number of issues have slowed its adoption by authorities responsible for highway bridge maintenance. Among the more important of these is the need for simple, quantitative ways to independently verify the quality of the treatment after it is applied. This paper presents the latest results of a research project currently underway with the primary goal of addressing this issue. The scope of this project includes: 1) fatigue tests on welds treated by UIT, 2) experimentation with possible quality control (QC) procedures, and 3) finite element (FE) analysis and fracture mechanics studies conducted with the goal of relating the fatigue test and QC results. This paper discusses the latest fatigue test and FE analysis results, focusing on how characteristics of the treated weld toe, such as the radius or notch depth, can be measured and related to fatigue performance.