The W. 7th Street bridge is a gateway between downtown Fort Worth and its cultural district. TxDOT designed the bridge with six arch spans across the Trinity River to improve safety, pedestrian access and add to the architectural redevelopment under way in this corridor. The project will widen and reconstruct the four-lane bridge with 10-foot sidewalks. It is the world’s first pre-cast network arch bridge.
ENR had an article in early June about the unique bridge (requires subscription to ENR):
Very carefully, of course! (You knew that was coming!)
DBA has had the pleasure of consulting with Sundt Construction on their effort to replace the West 7th Street Bridge over the Trinity River in Fort Worth, Texas. Our role has been to provide geotechnical consulting for the heavy lifts of the arches, as well as a VE design on a secant wall.
The aging Seventh Street Bridge, a popular east-west thoroughfare that connects downtown to the Cultural District, is due to be reconstructed.
The original span was built in 1913 and was expanded in 1953 when the Trinity River was rerouted and the surrounding levees were built. Although the bridge has been determined safe to use, beams, girders and the deck of the 1913 section are deteriorating.
To reduce the impact of closing the bridge, Sundt has installed new drilled shaft foundations on either side of the existing bridge. The twelve, 163-foot long, 300-ton concrete arches were fabricated off-site on the west side of the river. Large trailer dollies with 120 wheels move the arches from the yard to the site. Large cranes from Burkhalter (heavy lift and transport specialist) pick the arches from the dollies on the existing bridge and set them on the new foundations. The bridge is closed or partially closed during each lift. Once all of the arches are in place, the bridge will be closed to demolish the existing structure and build the new deck between the pairs of arches. The compete closure is supposed to last only 150 days.
Here is a time lapse video of the first arch being set:
The first arches were set over the weekend of May 11-12. Here are some links to video and articles: