Ultrasonic testing of more than 500 welded connections on the closed Interstate 40 bridge revealed nine locations requiring steel plating for additional support, the Tennessee Department of Transportation said Tuesday.
Plate design is underway and the material is being researched, the department added in its bi-weekly update on repairs to the Mississippi River crossing between West Memphis and Memphis. The manufacture of the plates will follow.
The update says the goal remains to reopen the bridge by the end of the month.[What do you want to know about the I-40 bridge closure? Ask your questions here Â» arkansasonline.com/bridgequestions]
A draft report on the inspection carried out by an external company, which the ministry received on Friday, indicated that no further deficiencies were found beyond that discovered by chance during an unrelated inspection on the 11th. may.
According to the update, the contractor “is making significant progress” on repairs related to the fracture discovered in May that affected the structural integrity of the span – also known as the Hernando De Soto bridge – including the installation of ” all structural elements and junction plates … at the site of the fracture. “
The last of the eight plates needed to replace the fractured zone was installed last week, the department said.
Work scheduled to take place this week includes minor drilling on small connection parts, final bolting, and tightening and detenting of the post-tensioning system, which is expected to be completed by Saturday. Once the post-tensioning system is relaxed, removal of the post-tensioning rods and solder / anchors will begin, the update said.
The bridge connecting Tennessee and Arkansas is an important trade corridor. Traffic was redirected to the Interstate 55 bridge, 3 miles south.
The crack on the I-40 bridge, an attached arched span, was found on a steel beam that connected strings to the arch. When the beam cracked, the load that was once carried by the beam shifted to other parts of the bridge.
The Tennessee Department of Transportation oversees repairs to the I-40 bridge, while the Arkansas Department is responsible for inspections. Kiewit Infrastructure Group of Omaha, Neb., Was engaged for the repairs.
Repair work on the bridge was carried out 24 hours a day, seven days a week. The fractured section of the I-40 bridge tie beam was removed on June 21.
The way the bridge is designed means the Arkansas Department of Transportation classifies it as a “fracture critic,” meaning that parts of the bridge are “under stress the failure of which would likely cause the bridge to collapse. part or all of the bridge “. Bridges critical for failure require frequent inspections but are not inherently dangerous.
The crack was discovered on May 11, but a 2019 photo, confirmed by transportation officials to be genuine, shows that the crack has potentially been around for years. Another photo appears to show a crack as early as 2016, but the authenticity of this image remains under investigation.
The discovery led the Arkansas Department of Transportation to fire the inspection team leader for missing the crack in at least two previous inspections, which are conducted each year.
Traffic slowed at a sustained rate in and around the I-55 bridge in the weeks following the closure of the I-40 bridge. But changes in traffic patterns and the closures of access and exit ramps put in place on both sides of the river in early June significantly reduced travel times in both directions.