For bridges that pass over and through bodies of water, conducting routine underwater inspections are mandatory to ensure the safety of the public. Besides the hands-on inspections that certified diving bridge experts do, they also use specialized equipment to find every possible damage.
Some states require underwater bridge inspections every 60 months, but regulations may differ from one state to another. To make sure that inspectors see and foresee any damages until the next examination, they use reliable visual and sonar equipment for the job.
Below are the advantages and disadvantages of these equipment:
Sonar Scanning Equipment
Sonar scanning is one of the most effective ways to detect cracks, honeycombs, spalls, and others. They are able to detect targets that are two inches in size.
An example of such equipment is an underwater gage, which measures thickness. It can provide accurate measurements up to 300 meters in depth.
However, some inspectors say that the downside of sonar equipment is that wave motions of the water may affect the findings.
Since sonars provide sound wave images, they do not provide the same visuals as cameras do. Inspectors can have a different view of the underwater structure as well as the conditions it is immersed in. The equipment may be carried by hand, or attached to the helmet of the certified diver.
The disadvantage of cameras is that the state of the water can affect what is visible and not. If the water is too murky or too turbulent, the camera might be ineffective.
Depending on the hired company, the equipment used and methodologies may differ on the type of bridge being inspected. To know which companies offer the best service, it is suggested to ask about their equipment and their effectiveness in finding damages. Though the divers are certified and knowledgeable, their findings are mainly based on what their equipment could detect.