Iowa Department of Transportation
North Clinton and Lansing, Iowa
B&N led the completion of fracture critical inspections for two truss bridges spanning the Mississippi River – the Iowa 9 and Iowa 136 bridges.
Both are continuous through truss bridges with main spans of 593 feet (Iowa 9) and 500 feet (Iowa 136). B&N engineers performed arm’s length inspections of fracture critical members in addition to routine inspections of all other components and approach spans.
The substructure on Iowa 136 was sounded and deterioration mapped for a future rehabilitation project. During the inspection of the Iowa 9 bridge, a critical floor beam crack was observed, requiring temporary closure of the structure while the floor beam was repaired. Inspectors accessed the bridge using rope access and climbing techniques, a pickboard, and a snooper truck.
Upon completion, the B&N engineers submitted a final report that included current conditions, repair recommendations, and CADD sheets with bridge deficiencies.