COLUMBUS, Ohio – Burgess & Niple (B&N), one of the nation’s leading engineering and architecture firms, recently sent an emergency response team to perform a post-earthquake inspection on an Alaska Department of Transportation and Public Facilities’ (Alaska DOT&PF) bridge that sustained damage following the November 3, 2002, earthquake near Fairbanks, Alaska.
The team was dispatched in response to Alaska DOT&PF’s concern that the Tanana River Bridge near Tok, Alaska, had shifted on its bearings and was out of alignment. The bridge, located on the Alaskan Highway, is a 946-ft.-long, three-span cantilevered through truss structure.
The response team used B&N’s adapted rock climbing techniques to gain access to all portions of the structure. Due to the remote locations of the site and the lack of mechanical access equipment in the area, these techniques provided a timely and cost-effective access solution for Alaska DOT&PF. In addition to the remote site location, the team was faced with freezing temperatures, wind gusts, aftershocks and snow-covered bridge members.
The team completed a detailed visual inspection of all superstructure members, an alignment survey of the truss centerline, and documented the bearing and abutment conditions. It was determined that earthquake damage was sustained at one abutment and one pier of the bridge, but the bridge remains safe for traffic.
B&N is currently working with Alaska DOT&PF to develop repairs for the damaged section of the bridge.
B&N’s response team consisted of four engineers from the firm’s Columbus, Ohio, Bridge Inspection and Bridge Design divisions. Team members were: Mark Bernhardt, PE, Facility Inspection Director; Ed Cinadr, PE, Bridge Design and Review Engineer; Patrice Grenier, PE, Facility Inspection Team Leader; and Dale Poorman, PE, Facility Inspection Chief Engineer.
The earthquake struck 75 miles south of Fairbanks, Alaska, at 1:12 PM, with a magnitude at 7.9 along the Denali fault line. According to the U.S. Geological Survey, the Nov. 3 shock is the largest earthquake on the Denali fault since 1912.