Abstract: Wisconsin Department of Transportation implemented anAnchor Bolt Inspection Program and Sign BridgeInspection Program in 1990 for cantilever & overheadsign structures, high mast light towers, interstatelight towers, and signal masts. All cantilever &overhead sign structures and high mast light towershave been inspected in-depth 'hands on' during thistime period while implementation of inspectioncontinues for interstate light towers and signal masts.The program requires an experienced inspection team anda practical inspection approach. Inspection preparationincludes review of all background information such asdesign plans, design computations, construction plans,shop plans, and maintenance history. An inspection planis developed. Special emphasis is placed on determiningtype of structure, type of material, welding details.For anchor bolts, type of material, cut or rolledthreads, type of coating, and method of placement areimportant issues. Inspection emphasis are on 'hands on'and Nondestructive evaluation. Special emphasis isplaced visual conditions of sign structures and anchorbolts (cut or rolled threads, straightness, corrosion,nut tension, etc.) along with ultrasonic inspection.This program places a strong emphasis on NonDestructive Testing (NDT), especially ultrasonic.Procedures and inspection calibrations for anchorbolts, are developed from similar anchor bolt geometryand material type. Cut notches are placed in the anchorbolts at locations of possible failure. NDT inspectioncalibrations are performed from these bolts. Reportdocumentation includes all design plans, pictorialdocumentation of structural deficiencies, sketches,nondestructive evaluation reports, conclusions, andrecommendations. This program has been successful inlocating critical cracks and failed members on existingsign structures and new sign structures less than sixmonths old. Also, failed anchor bolts and criticalcracks have been located on high mast light towers. !0
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