Inspectability of all bridge members and connections is an essential design-stage consideration.
This is especially apparent when the structure includes enclosed sections, such as box girders. Bridge service life has been impaired in the past when designers, concerned with stress distribution, either did not include access holes or made them so small it was impossible for an inspector to perform an adequate inspection. To ensure inspectability, experienced bridge inspectors should review the bridge design at an early stage of development.
Another consideration is safety of inspectors and traffic using the bridge during the inspection.
A preferred method of inspection has been use of a type of crane that allows easy access to underbridge members. But, on routes with very high traffic volumes, the presence of an inspection vehicle on the bridge creates a safety hazard to both inspection personnel and the traveling public. Other means of inspection should be provided in these instances, such as inspection ladders, walkways, catwalks, covered access holes, and provision for lighting, if necessary.