Missouri and Illinois Departments of Transportation photo
Crews connect the conduit to the driving surface.
A huge project involving the Mississippi River Bridge is headed toward completion next year. While the project owners are the Missouri and Illinois Departments of Transportation, the lead is the Missouri Department of Transportation (MoDOT), under project director Gregory Horn. The project is actually made up of nearly 40 smaller projects.
“This helps us to manage the overall cost of construction and allows us to schedule construction around the main span [the bridge],” said Andrew Gates, customer relations representative of the MoDOT St. Louis District.
The full dollar amount of the overall construction project is reportedly about $700 million. The cost of the main span is $239 million. Construction began in Feb. 2010, and the bridge and associated construction is scheduled to be open to traffic by early 2014.
The main span contractor is a joint venture between Massman of Kansas City, Mo., Traylor Brothers of Evansville, Ind., and Alberici of St. Louis, Mo.
The project includes a cable stayed bridge between St. Clair County, Ill., and St. Louis, Mo., and the realignment and reconstruction of Interstate 70 and numerous local roads on both sides of the state line.
According to Gate, the project includes the following key components: Missouri North I-70 Interchange; a roadway connection between the existing I-70 and the new bridge, with further connections to the local street system at Cass Avenue at St. Louis; an Illinois I-70 connection; a roadway connection between the existing I-55/64/70 Tri-Level Interchange and the main span; an Illinois Tri-Level Interchange; and improvements at the I-55/64/70 Tri-Level Interchange in East St. Louis, which will connect to the I-70 connection leading to the main span.
“Working on a river bridge, especially a river bridge over the Mississippi River, is always challenging,” said Horn.
“Early in the project, we lost several months of construction because the river was flowing at or above flood stage. We couldn’t safely stage our construction equipment for the initial foundation work. Now, less than four years later, we are experiencing exceptionally low water levels. That means that our contractor has to continually adjust their process to complete installing sections of the deck and the superstructure.”
Challenging projects often also have some unique aspects, as well.
“One unique element is building an iconic landmark about a mile away from another St. Louis iconic landmark, the Gateway Arch,” Horn said.
“This meant that as we went through the design process, we had to make sure that the new bridge’s design complemented, and in no way overshadowed, the Arch. Another unique element we had to deal with was the rock strength under the river bed. Our contractor suggested an alternate method of constructing the drilled shaft foundation for the bridge, based on special equipment they had. Our contractor proposed to install a test shaft to prove that their design would meet the strength requirements for our foundation. The test shaft maxed out the test equipment, and set a world record for drilled shaft strength.”
The main span construction includes 12,152,790 lbs. (5,512,413 kg) of reinforcing steel in the entire job. Each tower, including footing and shafts, contains 4,442,530 lbs. (2,015,098 kg) of reinforcing steel. There is a total of 16,367,840 lbs. (7,424,327 kg) of structural steel.
The tower height is 400 ft. (122 m), and each tower contains 7,768 cu. yds. (5,939 cu m) of concrete. In addition, each footing has nearly two million lbs. of reinforcing steel, and required 3,600 cu. yds. (2,753 cu m) of concrete. This required 400 trucks to pour continuously over a day and a half.
With a main span of 1,500 ft. (457 m), the bridge will be the third largest cable stayed bridge in the United States. It will require 600 mi. (966 km) of cables, which is enough to stretch between St. Louis and Kansas City and back.
Currently, large equipment on site for the main span construction includes a Manitowoc 7000 ringer barge mounted crane; two Manitowoc 2250 track cranes, one on a barge and one on land; one Leibherr LR1300 track crane on land; two Manitowoc 4100 track cranes on barges, two grove rubber tire cranes, two FabCo tower cranes (one on each tower), and two tugboats.
Throughout the job, additional Manitowoc cranes were used for short durations. This included a 4100 Ringer, a 3900, a 4,000, and two additional 2250s.
Contractors on associated projects include Millstone Bangert, Fred Weber, Keeley and Sons, Kilian, Baxmeyer, Hanks Excavating and Landscaping, Petroff Trucking Company Inc., Insituform Technologies, Hayden Wrecking, Moniger Excavation, Halverson, and Mason Landscaping.