A bridge inspector is a civil engineer construction specialist. Inspectors are familiar with the load rating analysis system required for designing bridges, parking garages, and other transportation-related structures. In addition, they are able to perform condition assessments on aging bridge structures and often add input into the rehabilitation design for public highway construction. A bridge inspector is also generally part of a team that participates in the business development of new roadway infrastructure from its inception.
At the very minimum, in the US, a bridge inspector holds a Bachelor’s Degree in civil engineering and must continually be educated and seek certification. Their work requires the understanding of a broad range of the history and precedents in bridge design and maintenance. Typically in the US, he or she will be a citizen who works under the guidelines established by both the federal and state governments, and is responsible for applying National Bridge Inspection Standards (NBIS) to his work.
As a novice team player, a bridge inspector gains experience in bridge structure, construction and how those elements operate under various stress factors towards a comprehensive understanding of structural behavior. For all practical purposes, he will learn how to construct a sound bridge that meets various code and environmental requirements and passes safety measures allowable for public use. It is not unusual for him to need some years of apprenticeship before he can work with an experienced crew.
Often an experienced bridge inspector will be called upon to do damage inspections. These examinations are meant to assess the structural damage that result from environmental or human actions over time. There is an expression used in federal inspections called “hands-on inspection of the critical fracture,” which means the worker must physically place his hands on the fracture (also referred to as a tension area) no matter where it is found. Whether high up in the air or underwater, a bridge inspector can be found performing any and all tests as determined by the program manager.
Load capacity and steel column strength are just two of the mathematical calculations bridge inspectors deal with daily. Due to structures being vulnerable after a flood event or other type of catastrophe (from collisions to fire) they are often found traveling. Once on-site, a bridge inspector will look for fatigue cracking, corrosion, and sometimes don underwater gear to study construction below water's surface to monitor for “scour,” a harmful sediment.
New assessment techniques such as magnetic particle and ultrasonic inspection are being used with greater frequency, helping to augment the standard visual inspection in practice. Some bridges are being outfitted with acoustic emission monitoring devices that detect the sounds produced when a crack grows.