Serving as the gateway into Nashville, the Broadway Viaduct Bridge spans five railroads, 11th Avenue South, and a greenway. Motorists exit into downtown Nashville, the Music City. The Tennessee Department of Transportation (TDOT) recognized that this vital bridge was at the end of its service life and needed to be replaced.
Roughly 26,000 vehicles cross the bridge each day. The project team implemented Accelerated Bridge Construction (ABC) techniques to make sure the work was finished on time without disrupting commuters that much.
The team developed full-depth precast deck panels tied together with closure pours. They erected simple span beams without any field splices that were made continuous over the bents for live load. This reduced the construction’s effect on motorists and adjacent property owners.
The precast deck panels had windows in the panel for the shear studs on the top flange of the steel girders. This provided connectivity to the bridge slab when the windows were filled with concrete.
Crews thread horizontal reinforcing steel through holes in the web of the steel girders. The concrete diaphragm was poured over the bent cap, encapsulating the girder ends. And on the west end of the structure, the bridge was shortened and converted into a roadway.
The team ran into challenges when utility lines ran between beams for the length of the bridge.
Not wanting to relocate the utility lines because of the cost of relocation and the delays to the construction it would cause, Gresham Smith’s utility team designed temporary and permanent conduit supports to maintain the feed into downtown Nashville.
The project team faced other issues. The grade of the new bridge had to be raised over CSX rail lines for vertical clearance and come back down to meet the front entrance of the Union Station hotel.
Using subsurface utility engineering, the project team analyzed relocation plans with the roadway and bridge plans to ensure there were no conflicts.
The project team worked closely with CSX to coordinate traffic on the roadway and the rail lines. Weekly meetings were held for safety procedures and coordination with the CSX flagman and track supervisor.
Despite the challenges, the project team finished on time and the bridge opened on Halloween of this year. RB
Project: Broadway Viaduct Bridge Replacement
Location: Nashville, Tennessee
Owners: Tennessee Department of Transportation
Designer: Gresham Smith
Length: 700 feet long and 98 feet wide
Completion Date: Oct. 31, 2023