Non-destructive evaluation techniques for steel bridges inspection

Bridges, roadways, transit, water and sewer networks are main components of a civil infrastructure system. Billions of dollars are invested annually on infrastructure assets in Canada and the United States to cope up with growing population and to maintain serviceability and safety. Civil infrastructure systems contribute to social and economic welfare through serving large number of population and businesses. Thus, evaluating these systems' condition and performance is a necessity. One in four Canadian roads is operating above capacity, highlighting a real challenge to moving goods and people within our communities in the short and medium term. Steel bridges deterioration has been one of the problem in North America for the last years. Steel bridges deterioration mainly attributed to the difficult weather conditions. This paper review the steel bridges defects and the current practices for steel bridges inspection. Visual inspection is the most common technique for steel bridges inspection but it depends on the inspector experience and conditions. So many NDE models have been developed use Nondestructive technologies to be more accurate and non-human dependent. Nondestructive techniques such as The Eddy Current Method, The Radiographic Method (RT), Ultra-Sonic Method (UT), Infra-red thermography and Laser technology have been used. Through this paper these NDT will be reviewed with the advantages and disadvantages of each technique. Then recommended improvements will be presented to enhance the current practices and overcome their drawbacks and limitations.