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The Department of Transportation for the State of California (Caltrans) abides by the regulations of the Federal Highway Administration's National Bridge Inspection Standards section 650.305 that states that bridges are to be inspected at regular intervals not to exceed two years. The Division of Structures, Office of Structures Maintenance and Investigations is responsible for the inspection of approximately 26,000 bridges in California. Approximately 3,100 of these are steel bridges and of these, 1,000 have fracture critical members. Fracture critical members are tension members of a bridge whose failure will probably cause a portion of, or the entire bridge, to collapse. In 1980, the Division of Structures established a category 'A' inspection program which identified what fracture critical features were on the steel structures. All of the 'ingredients' are present for steel structures to develop cracks. The age of the structures has increased along with the average daily truck traffic and their loads. The material properties required in the 1950s and 1960s did not have requirements for fracture toughness. Proper welding procedures/quality remain a challenge to achieve today, and those structures that are 30 to 40 years old were not immune to this problem. Caltrans has 12 districts in the state with at least two area bridge maintenance engineers (ABME) per districts. Caltrans requires that the ABME be a licensed civil engineer. The ABME faces a heavy responsibility when inspecting fracture critical members. The ABME is not trained in different methods of nondestructive evaluation (NDE), which is not unusual for an engineer graduating from a four-year engineering curriculum. Beginning in 1985, the Welding and Metals Technology Branch of the Transportation Laboratory assisted the Division of Structures in the inspection of these fracture critical features using NDE methods. As of 1990, the Welding and Metals Technology Branch's Fracture Critical Inspection Team accompanies AMBEs on their scheduled category 'A' inspections.
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