Major Excavation In North Aurora

By Larry Trojak | September 28, 2010

Many people harbor the misconception that all development projects are alike — that is, simply level it, clear it and build it. For those who do, a look at the area that will soon be home to the North Aurora Town Centre should convince them otherwise.

The 330-acre site contains 100 acres of wetlands that have to be relocated before construction can begin. However, doing so in accordance with environmental mandates set forth by the U.S. Army Corps of Engineers has proven to be one of the most challenging — but rewarding — aspects of any project undertaken by Rubloff Excavation, LLC.

Unique Development

Located about 45 miles west of Chicago on Interstate 88, North Aurora is the next logical extension of a metropolitan area that continues to expand outward in every possible direction. As people relocate, sites like the North Aurora Town Centre with its nearly 600,000 square feet of available rental space will provide for their needs. According to Bob Marsh, president of Rubloff Excavation, the firm charged with making the site construction-ready, getting to that point has been anything but routine.

"Not only is the largest excavation project we have ever undertaken, it has also been the most complex because of the 100 acres of corps-approved wetlands that has to be created," he says. "And it has to be created in a planned, sequential order which will ensure the least possible amount of environmental impact, with regular inspections by Army Corps, soil and water, and conservation officials along the way."

The need to create the wetlands area stems from past construction of an auto mall located adjacent to the site. That location was initially designed to retain an area as wetlands. By the time it was completed, however, the wetlands concept had become little more than a pond. Marsh says when Rubloff Development Group negotiated to buy the property, a clause in the agreement said that in exchange for relocating the streams that ran through the center of the property the firm would create 100 acres of new viable wetlands.

Slow Beginnings

It's hard to say if any contractor is really equipped to tackle a project with the constraints and demands present at the North Aurora site, but Rubloff's resources and willingness to work with the Corps of Engineers kept the project moving along, even during some taxing early periods.

"The early part of the project was held up for about 2-1/2 months, again mostly due to sequencing constraints," says Marsh. "With the right equipment on a job like this, we can easily move 1.5 million yards of dirt in 40 to 60 days; having the entire site available to you makes that possible. But this is not like any other job. Here we had to first dig diversion channels, stabilize them, plant them, and then reroute the creeds on-site."

With that done, Marsh says they created a number of wetland areas, mindful of strict adherence to elevation, outfall elevations and so on, to maintain appropriate water levels. Different plant communities have been designed into each of the levels of wetland elevation. A 40-acre basin, for example, might have five different plant communities designed into it.

Sculpted mounds can have 6 inches of water covering one part, then be tapered down and terraced to a depth of 1 foot, then 18 inches, then back up to just damp and again to dry, with a different plant species and community on each of those levels.

"We even had to put dead trees into several areas, making us one of the few projects with line items in their budgets to buy dead trees to be strategically placed in the bottoms of ponds," Marsh says.

Bringing In The Iron

To handle issues related to wetland plantings and the like, Rubloff hired both a wetland consultant and a landscaping firm, both of whom specialize in that area. To do the actual earthmoving and development, the company called upon its own strengths: an impressive fleet of Terex equipment, utilizing everything from an HR-18 mini excavator to a TXC-470 excavator and almost everything in between.

Removing The Spoils

Rubloff got to utilize the largest piece of equipment in its fleet — the TXC-470 — in the early stages of the project when a berm left over from the auto mall's construction had to be removed.

"This mound was probably in excess of 200,000 yards of dirt that had to be hauled out before work could proceed on that area," says Steve Full, Rubloff's project superintendent. "We had a steady stream of 18-yard TA-40 haul trucks being fed by the 470 with a 4.5-yard bucket, and they were staging and leaving every minute or so. The 470 really set the pace; it had that berm down and the dirt redistributed to low areas throughout the site in no time."

Marsh says they initially mobilized more equipment than was necessary during the early stages of the project — nearly 40 pieces of Terex equipment alone — but knew that once the creek diversion channels were cut, stabilized and inspected, things would open up.

"Once we got to that point, it opened up nearly two-thirds of the site for us," he says. "Things were also complicated by the wide range of material we've encountered — everything from a gumbo-like clay to sand and cobbles — and the area's high water. So, creating several basins on-site — some of which have 200,000 yards to 300,000 yards of fill excavated and used to build beds in areas in the creek bottom — took a wide variety of equipment based on what layer of soil we were in. Tractors pulling Ashland scraper pans worked great in the topsoil and in the clay where it was dry. However, as soon as they got into the sand and wetter material they bogged down and we had to switch to the Terex 14G scrapers. We ran those until we got to a point where traction became impossible, then set the TXC-470 out there feeding the 40-ton off-road trucks."

Additional Benefits

Rubloff has 14 trucks committed to the North Aurora project. Should they still need additional capacity, however, or if haul distances get too long, they are prepared to top-load the scraper pans and the 14G scrapers for additional volume.

As challenging as the project has been, Marsh is quick to add that it has also proven beneficial from a number of standpoints. "A project like this tends to scare some contractors," he says. "Over the course of this job, we will have monitored the design, done the entire permitting process, handled the budgeting, and done all the earthmoving, site utilities and wetlands before turning it over for construction to begin. So it really will have been a turnkey, full-service operation, and that, coupled with the equipment we can bring to bear, allows us to compete in areas in which many others simply aren't equipped to operate."

He adds, "The development arm of our company has projects ready to go throughout Illinois and elsewhere in the country; North Aurora has us better prepared for anything those projects have to offer."