The one kind of surprise you want when you have gone to great lengths to plan the moving of an entire bridge section is when things slip and slide along even more smoothly than expected.
That’s what happened last weekend in Cleveland. It is a story of planning, good luck, checked calculations and final success.
Using a painstakingly coordinated cast of hydraulic rams and jacks, crews performed a memorable 4-in. westward realignment of 10,000 lbs of the Innerbelt Bridge over the Memorial Day weekend. The feat frees up an expansion joint on the bridge’s west section, previously blocked by the eastward shift of the truss due to a slope’s slow slide on the western end of the Cuyahoga River.
The 5,078-ft-long crossing, consisting of multiple cantilevered steel truss spans, carries Interstate 90 over the Cuyahoga River into downtown Cleveland. Pier 1 at the west end of the bridge sits on friction piles in a slope with slip plains. “The slope wants to move into the river,” says Tom Hyland, area engineer for District 12 of the Ohio Dept. of Transportation. “The bridge moves with the slope. That is what closed up the expansion joint.” In 1999 ODOT installed a tieback system with drilled shafts 150 ft deep in the slope to mitigate movement.
Working under a $892,000 contract, Ruhlin Co., Sharon Center, Ohio, and a cast of 20 ironworkers gathered early May 23 to close the bridge to traffic. The first step was to vertically jack the truss up four inches and install an 80 in. x 74 in. composite steel plate underneath the bolster, the fixed piece that connects the pier cap to the superstructure, says Chuck Fisher, Ruhlin structural group general manager. The 2-inch-thick plate, its top layer of stainless steel, had two sheets of Teflon bonded to it, he says. Crews removed the anchor bolts from the bolster, jacked it up 4 in., slid the steel plate underneath, and lowered it back down.
Crews then prepared to push the 525-ft-long section of bridge westward with four 250-ton hydraulic rams, attached to the east side of the pier, says Fisher. There were also 150-ton jacks installed in the deck west of Pier 1, 100-ton rams attached to the bottom chords at the east end of the truss, and 100-ton rams at six locations along the stuck expansion joint, says Fisher.
“We had to monitor the pressure at each pump,” he says. “We had four steps to follow to gradually bring up pressure on the bridge.” Consulting engineer Richland Engineering Ltd., Mansfield, Ohio, had calculated that the bridge would begin moving near the end of step 2, but “the bridge started to move almost immediately,” with less than 100 tons of force applied, he recalls. “We stopped because Richland wanted to go through more calculations.”
Hyland says that based on a similar realignment 10 years ago, “we thought we’d have more rust and friction to overcome. But it moved better than we thought. The plates worked very well. We’re very happy we didn’t have to get up to the pressures we’d calculated.”
With crew members in constant communication, the bridge push commenced for 2 inches, then only the rams on the bottom chord were utilized, says Fisher. The moved bridge section actually includes a truss over the west slope and 300 ft of a truss over the river. That latter section didn’t travel as far as the westernmost section, so hydraulic rams located on its chords “gave it a nudge to catch up,” says Hyland. “Once we started applying force just to the bottom chord...there was quite a bit of noise,” adds Fisher. “..loud banging and shaking.” State wildlife officials stood by to ensure that the nest of a peregrine falcon couple on the bridge stayed intact.
Ruhlin had to reopen the bridge for downtown holiday events and come back early Sunday morning to complete the job. “ To close the bridge during a weekend with so many events was the most challenging thing about scheduling the project,” says ODOT spokesperson Jocelynn Clemings. But the following weekend would have been even more difficult, because the Yankees are in town playing the Cleveland Indians, adds Hyland. Steel braces locked the bridge in place for Saturday traffic.
On Sunday, the crews jacked up the bolster again to remove the steel plate, lowered it and installed new anchor bolts. By June’s end, the contractor will have removed all temporary steel and cleared the site.
The Federal Highway Administration mandated that the bridge realignment occur before May 31, due to concerns about thermal expansion. “We put plans together in February and got them out on the street late March,” says Hyland. “A traditional project—we’re talking 16 weeks of advertising, getting signatures. The review process would be 6-8 weeks.”
Bidders had a week and half, recalls Fisher. Ruhlin left $250,000 on the table, thanks in part to consultation with ironworkers, he says. “We sat for six hours and talked the job through...then determined our final price.” The ironworkers fabricated 90,000 lbs of temporary steel needed to support the jacking on site in 30 days, finishing two weeks ahead of schedule, notes Hyland.
Overall work is far from over. “We still have an additional $10-million steel repair job coming this summer,” says Hyland. And stimulus funds will help ODOT plan for a new westbound structure in the next 18 months or so, he adds. “Once that structure is completed, we’d like to build a new eastbound structure if funding allows, or rehabilitation.”