When District 3 engineers needed more personnel to meet state and federal government requirements for National Bridge Inspection Standards (NBIS), they turned to Fehr Graham. Mary Coombe Bloxdorf, a structural engineer with Fehr Graham, has performed NBIS inspections for Livingston and Grundy counties since 1996. Several counties and the Illinois Department of Transportation (IDOT) tapped Fehr Graham as a qualified firm to help.
Fehr Graham can inspect 12 bridges per day, depending upon location, bridge conditions, channel geometry, water depth and weather condition.
The IDOT Structural Services Manual outlines inspection requirements. The routine form in the manual identifies which items must be addressed during inspection. The Illinois Highway Information System Structure Information and Procedures Manual provides the inspector with condition rating guides, which the inspector uses to code each item’s condition. The codes range from a 9 (for new structures) to a 2 (bridges in critical condition).
When an item is deemed critical, the inspector immediately reports to the Bureau of Bridges and Structures and makes the decision to divert traffic from the problem area or close the structure, if necessary. The Bureau then confirms the inspector’s findings and recommendations. The forms are sent to the District and entered into their database.
Inspection personnel must be certified with IDOT as an NBIS Team Leader or Program Manager. Coombe Bloxdorf, Tim Souther and Keith Brandau are Fehr Graham’s certified bridge inspectors.
Inspections of the Iroquois County bridges started in July.