Trimble GPS machine control used on subbase improves final rideability

When talking highways in America, everyone knows that the capital letter “I” preceding a number stands for “Interstate.” There's I-94, which runs from Montana to Michigan. There's I-80 that runs from New Jersey to California. And there's I-96, which... well, starts in Norton Shores, Mich. and ends in Detroit, Mich. One can say, it connects Lake Michigan to Lake Huron. The “I” should probably stand for Intrastate, but it doesn't. Every mile of Interstate-96 is within the state of Michigan.

A little more than six miles of the 192-mile-long, well-traveled, I-96 highway is currently undergoing major reconstruction. The Michigan Department of Transportation (MDOT) project was initiated in August 2009 and is scheduled to be completed by the end of November 2010. With a $10,000 per day late penalty, bets are that the project will be done on time.

Interstate Highway Construction, Inc., with its Midwest office in Owosso, Mich., is the general contractor on the project. The I-96 freeway reconstruction project includes widening the shoulders, updating a rest area parking lot and its exit, and reconstructing six ramps, including the two connected with the rest area.

Kalin Construction, Sodus, Mich., won the dirt portion of the total $25 million contract. The company will tear out the old road down to its sandy sub base and then establish new courses up to the concrete paved surface, which Interstate Construction will lay.

“We removed eight inches of continuous-reinforced concrete, which had a four-inch asphalt overlay,” states Mark Bruzek, project manager, for Kalin Construction. “The removed concrete was crushed in our portable crushing plant and then reused on the site.” The reinforcing wire mesh and the asphalt that was milled off with the company's Wirtgen W 2000 cold milling machine was trucked off-site to be recycled.

“The plan called for widening the shoulder from five feet inside, seven feet outside to 12 feet inside and 12 feet for the outside shoulder,” Bruzek says. “To undercut and widen the highway shoulders we used Cat D6N and D6K dozers equipped with Trimble^® GCS900 Grade Control Systems.” A total of 269,000 cubic yards of soil was moved over the entire I-96 reconstruction.

According to Bruzek, Trimble technology has been instrumental in helping Kalin maintain the tight schedule, even with the atypical wet weather conditions.

“With Trimble GPS, we cut the on-site surveyor's time in half and eliminated most of the staking and string lines,” Bruzek states. “We reduced the survey team from three to two-a survey chief and a grade-rod person.”

Kalin Construction has been leveraging GPS and construction total station technologies since 2005, working with its local Trimble construction technology provider, SITECH Michigan, Novi, Mich-one of Trimble's independent SITECH technology dealerships around the world.. Before the company moved onto the site in force, Bruzek took the paper site plan prepared by MDOT and built a digital 3D model using Trimble Terramodel^® office software. “The digital plan allows for greater detail and quality control of our work on the site.”

Topo data for the plan was confirmed and progress was monitored through Trimble site positioning system portable rovers-SPS880 and SPS882 Smart GPS Antennas that are paired up with TSC2^TM Controllers, hand-held-sized computers that measure, compute volumes, and use the digital 3D model that Bruzek created.

Kalin Construction had five pieces of heavy equipment working on the site-all of them equipped with Trimble GCS900 Grade Control Systems. Two motor graders and three dozers-two with fully-automatic GPS systems and two with indicate systems.

“Using the Trimble systems allows the operator to get to grade faster than ever, even with the complex I-96 designs,” states Bruzek. “The on-board Trimble CB430 Control Box determines the position of each tip of the motor grader or dozer blade and compares it to the design elevation to compute cut or fill to grade. The cut/fill data is used to drive the valves for automatic blade control or is passed to in-cab light bars that provide visual guidance to the operator when using the indicate-only systems.”

“One of our biggest challenges was to make sure we achieved the mandated grade with the 12-inch sand base,” Bruzek states. “We were moving 176,000 cubic yards of sand, so to achieve the expected +/- 1/2 inch we relied on our Trimble total stations to achieve the fine-grade accuracy.”

Kalin used both its SPS730 and SPS930 Universal Total Stations that feature Trimble MultiTrack technology that locks-on and tracks passive prisms for applications such as monitoring or controlling measurements, and active prism targets for dynamic measurements required for grade control.

After the sand base, Kalin Construction placed a six-inch open-graded drainage course using 4G-grade gravel, created on site from the company's crushing plant recycling the old concrete. The company had used its Impact Roller Technology Impactor 2000 for breaking up the concrete into 18-inch pieces, which were small enough to feed the crushing plant.

With the Michigan I-96 project's finish line in sight, Bruzek reflects: “We've worked for Interstate Highway Construction on other projects so we intend to achieve the same quality results on the I-96 project as we have in the past. We want to hear them tell us again that 'The quality of your grade is so good that it improves the ride ability of our concrete surface.' It can't get better than that.”