Development of NDE techniques for the maintenance of long-span steel bridges based on infrared measurement

摘要

Propagation of fatigue cracks from welded joints in steel bridges is one of the serious problems associated with the deterioration of ageing infrastructure. Inspection of the deterioration such as fatigue damage or corrosion is necessary for ensuring safety and estimating the remaining strength of the steel bridges. In this respect, nondestructive testing (NDT) and nondestructive evaluation (NDE) techniques play important roles. The present author has been conducting cooperative researches with Honshu-Shikoku Bridge Expressway Company Limited on the development of remote NDT- and NDE-techniques using infrared thermography for the effective maintenance of large steel structures. In this presentation, some experimental studies conducted for fatigue crack detection, estimation of fatigue crack propagation based on fracture mechanics and evaluation of strength recovering by repair work using infrared thermography are shown.