The Illinois Department of Transportation has finally given the go-ahead for a plan to cut a trench through the bed of Salt Creek in order to reroute a 16-inch water main, which will allow the Brookfield Avenue bridge reconstruction to continue.
The village received notice on Dec. 7 that the approximately $470,000 operation had gotten IDOT’s blessing. Demolition operations had ceased at the site on Sept. 3 after two attempts to bore a hole under Salt Creek failed when the drills hit unknown obstructions about 10 feet under the riverbed.
No work has taken place at the site since that time and village officials have been waiting for IDOT to review and sign off on plans submitted by their general contractor, Lorig Construction.
IDOT’s approval was necessary because 80 percent of the cost for the work – initially pegged at about $3.5 million — is coming via a federal grant, and such an expensive operation was subject to formal review. Brookfield is responsible for paying 20 percent of the project’s total cost.
The final cost of the project will be closer to $4.5 million, based on change orders already approved by IDOT. Including the cost for trench cutting, IDOT had OK’d additional costs amounting to about $835,000, according to a change order authorization document obtained by the Landmark in a public records request.
While Village Manager Timothy Wiberg had hoped the trench cutting operation could take place prior to the end of 2021, those hopes have fizzled. It’s not clear exactly when that work will begin, but Wiberg said his expectation was that it would take place in January.
Village officials believed when the Brookfield Avenue bridge construction contract was approved in April that the new structure would be in place by the end of the year. The water main relocation, needed to accommodate the superstructure of the new, wider bridge, doused those hopes this fall.
An unexpected benefit from the need to cut a trench for the water main is that ComEd will now relocate an overhead power line that last summer was the cause of some consternation and held up work for two weeks.
The power line will now run through a conduit that will be placed alongside the water main in the new trench. The move will eliminate the need for utility poles and overhead power lines west of Salt Creek. ComEd has agreed to pay a portion of the $470,000 cost for the trench-cutting operation.
Brookfield’s village engineer, Derek Treichel told the Landmark that the trench-cutting/water main/Com Ed installation would take about a week to complete, with the entire project to tie in the rerouted water main taking two to three weeks.
Depending on weather, Lorig could decide to resume demolition prior to spring. Officials expect to provide an updated work schedule in early 2022.
Given the series of problems that have held up demolition and construction of a new bridge, Wiberg said he wouldn’t hazard a guess on when in 2022 the project will be completed.
“All I know is that it is my hope, my expectation, that we get the water main work done over the winter so that, as soon as spring comes, Lorig can get back out there,” Wiberg said. “After that it shouldn’t take that long to complete, but I wouldn’t venture a guess on when that’s going to be.”
The trench-cutting operation itself will be fairly elaborate, according to a site plan obtained by the Landmark through a public records request. The initial phase of the operation would involve sinking two sheet-pile cofferdams into the riverbed north of the Burlington Northern-Santa Fe Railroad right-of-way. Water will be pumped out of the area between the two dams to expose the riverbed for cutting the trench.
In order to keep the river flowing downstream with the dams in place, six 18-inch diesel-powered, end-suction pumps will be placed on the east bank of Salt Creek north of the upstream cofferdam.
The pumps will be designed to move 50,000 gallons of water per minute through three 24-inch high-density polyethylene lines that will run up the riverbank and then south across the village hall parking lot before heading west back into the river south of the downstream cofferdam.
When the new bridge is in place it will be wider than its predecessor, a 1986 bridge deck set atop three concrete piers dating from 1916. There will be no central pier supporting the new bridge, allowing the river to flow freely beneath it.
Pedestrians won’t have to squeeze by one another crossing the river along the north side of the bridge, which will sport a 10-foot-wide walkway in addition to a semicircular bump-out creating a small plaza overlooking the river.
Traffic will be separated from the walkway by a short wall, and the bridge will also be equipped with decorative lighting.