Demolition moves into new phase on old Interstate 74 bridge 

The arduous process of dismantling the old Interstate 74 bridge quietly hit a milestone on Monday, Jan. 9, as the last chunk of concrete pavement was removed from the twin spans by a demolition crew. “As of 9 a.m. today we finished removing all the decking on the bridge,” Tom Schebler, a project engineer for […]

The arduous process of dismantling the old Interstate 74 bridge quietly hit a milestone on Monday, Jan. 9, as the last chunk of concrete pavement was removed from the twin spans by a demolition crew. “As of 9 a.m. today we finished removing all the decking on the bridge,” Tom Schebler, a project engineer for Helm Civil, told a crowd of nearly 50 gathered for the Moline Rotary Club’s meeting. To date, he said crews have removed about 5,000 cubic yards of concrete and 4 million pounds of steel – “with about 12 million more to go in the river and another few million on land.”   Joining I-74 Corridor Manager George Ryan as a guest speaker, Mr. Schebler provided a detailed update on the demolition work and the progress of the $23 million contract awarded to Helm Civil, the former Civil Constructors in East Moline. The project is being led by the Iowa Department of Transportation (DOT) in coordination with the Illinois DOT.  While concrete deck removal began in September on the Moline side, Mr. Schebler said demolition planning actually began in early 2022.  The engineer, a 2020 Iowa State University graduate, described how crews used diamond blade saws to cut 4-foot by 12-foot sections of the former roadway. “Those 4 by 12 slabs weighed 7,000 pounds apiece,” he said. He showed photographs of the slabs being picked up by an excavator, which then passed it back to a loader that drove it off the bridge to be crushed into rock. Metal rebar was also recycled from the old roadway.  “This is a rather difficult bridge to demo because of the way they were built and put together, they’re pretty massive structures,” said Mr. Ryan, who spent the past five years in the QC coordinating the project’s public communications. “You’ve got environmental issues, especially the slough on the Illinois side … so there were a lot of things that really made the construction of the new I-74 bridge as well as demolition of this a little more difficult than your everyday bridges.”  Mr. Ryan continues to lead communications for the project for the Peoria, Illinois-based Wood Environment & Infrastructure Solutions but also has assumed a new position as vice president - construction services for Terra Engineering LTD., also in Peoria. During his 34-year career with the Illinois DOT career, he oversaw numerous infrastructure projects including the $500 million reconstruction of I-74 through Peoria.  “(The I-74 bridge project) went remarkably smooth given the magnitude of the work we did and the timeframe in which we did it,” he said of the $1 billion I-74 bridge that opened in December 2021.

Focusing on the demolition work, Mr. Schebler told the Rotarians that the old suspended span measures 740-foot-long with about a 60-65-foot channel clearance depending on the Mississippi River – and 87 feet from the roadway height to the top of the suspension towers.  Helm’s total demolition project from Ramp A in Bettendorf to Moline bank measures one mile, he said.   Mr. Schebler, who has shared the bridge demolition story many times over the past few years, had the crowd laughing when he said, “When are we going to blast it? When are we going to blow it up?”  In the original plans, he said a major explosive component was suggested. “In our pre-engineering, we decided that was not the best option that suited what we wanted to do. Just due to the schedule restrictions with a blast like that, the environmental restrictions and the navigation restrictions.   “While we’re not going to have a big blast of all that deck steel, we still are planning to blast the cables and towers and drop them into the water and recover them,” he said, estimating that will occur in late spring or early summer for one bridge and a few months later for the other.  By using river scanning technology, Mr. Schebler said crews can determine any materials that go into the river – which must be retrieved per the contract. A post-scan will be done after the work is completed to ensure all materials are recovered, he added.  The pair estimated the entire demolition would be completed in 2024 but stressed that many more components of the demolition still are being engineered and await review and approval by a multitude of agencies.  “We still have a lot of work ahead of us but things are going well right now, which is good to report,” Mr. Schebler said.  However, he told the QCBJ following the Rotary club’s lunchtime program at Trinity Lutheran Church that “The heavy lifting is still to come – removing the towers and steel removal is pretty difficult work.”  As work shifts toward steel removal, he said Helm will bring in a 300-ton crane to join the equipment already on site including four cranes, 11 excavators, eight manlifts, crew boats, push boats, and equipment barges.    In addition to demolition, the former Civil Constructors also had been involved in new bridge’s construction – building the two Iowa viaducts. “We’re usually on the building (side of the business),” he said, adding the demolition is the “largest magnitude project” now underway for Helm.  With the driving surface removed as of Monday, Mr. Ryan said the next step will be to take the actual steel decking off and removal of the Bettendorf ramp, which had allowed demolition crews access to the span. Then demolition will move toward removing the suspension spans.  “They’ve been very lucky (weatherwise),” Mr. Ryan said, adding “... Mid-November I thought we were going to have one of those kinds of winter.”   He credited Helm and its team with “really engineering this” and finding options that have saved taxpayers money. “They put the money up front in engineering and it’s really saved money and time in the processes they are doing.”