Martin Marietta Maximizes Million-Dollar Weekends
When the E-470 Public Highway Authority was ready to begin the second half of a major widening and overlay project last year, the success of phase one was still relatively fresh.
Performed in 2017, the first portion of the E-470 expansion, between Parker Road and Quincy Avenue, earned a Best in Colorado quality award from the Colorado Asphalt Pavement Association.
To widen and overlay E-470 from Quincy to I-70, the Authority brought together much the same team: Martin Marietta, Raleigh, N.C., as asphalt paving subcontractor and Kraemer North America, Plain, Wis., as prime contractor, this time alongside SEMA, Centennial, Col.
“We worked really well together last time, and E-470 wanted to keep the same team together for this phase,” said Martin Marietta General Manager Trevor Norton.
E-470 is a toll road circling the eastern half of Denver, an area that is experiencing significant development and population growth.
The genesis of these projects was a traffic and revenue study the E-470 Public Highway Authority performed to track current traffic trends and projected traffic growth. Forecasts from the 2020 Master Plan prepared by SEH, Denver, Colorado, show a 47 percent increase in population in the E-470 influence area between 2015 and 2040 and traffic throughout the corridor is projected to increase by 80 percent between 2018 and 2040.
Although the entire region is expected to continue its rapid growth, SEH forecasts particularly dramatic growth in the eastern part of the metro area. In fact, E-470 traffic is expected to grow at a considerably faster pace than overall area growth. The report suggests that this may be because many adjacent untolled highways and arterials are expected to reach their capacity and experience more congestion. However, E-470 “is expected to maintain adequate capacity to fully accommodate growth in travel demand.”
The E-470 Public Highway Authority’s goal is to provide a traffic level of C or better at all times, including rush hour, for its customers. “With this goal in mind, we continue to plan for widening to add capacity in advance of projected volumes,” Brady said. “Commitment to quality by the Authority, and our contractors, is crucial to this goal as well.”
The second portion of the E-470 widening project will play a major role in doing so. This phase of the project adds a third lane in each direction to an 8-mile stretch from Quincy to I-70 and overlays the entire width with SMA.
“Having basically the same team in place for this second widening project has been a benefit to the success of the project,” said Jim Brady, Construction Manager for E-470 Public Highway Authority. “Through this on-going partnership, unknowns become known, cost risk can be identified and allocated, project costs are predetermined and fixed, and change orders can be minimized.”
“We were part of the earlier phase, so we knew the owner’s expectations,” said Martin Marietta Project Manager Zach Schmidt. “With the same parties involved, there were no surprises.”
As they had done during the last portion of the project, the crews performed the widening portion of the project behind barriers. This decision meant haul trucks could utilize E-470’s on/off ramps without going in and out of live traffic, but it also minimized lane closures and allowed the crew to work longer days without impacting traffic.
Prior to paving, the job required minimal patching, as well as milling around bridge decks, toll plazas and tie-ins for ramps.
In addition to adding a new lane in each direction, Martin Marietta also expanded the shoulders so the highway will have 12-foot shoulders both inside and outside of the travel lanes. The SMA overlay across the full width of the highway was added to get the slope and drainage right for the new width, as well as cap the whole span of lanes.
“The Authority does a good job maintaining their highway, so the road is actually in pretty good condition,” Norton said. Rather, it’s a matter of preparing for the future. “By continuing to build the thickness of their pavement, they’re preparing the road for higher traffic loads in the future.”
The SMA portion of the project was paved on weekends, when the crew could close two lanes. From 6:30 a.m. until 6:30 p.m. on Saturday and Sunday, Martin Marietta ran two pavers in echelon, putting down upwards of 6000 tons of SMA per weekend. On a particularly successful weekend in the middle of August, the crew was able to place 7200 tons in two days.
“We called those million-dollar weekends,” Schmidt said, “because by Sunday afternoon they’d cost us about $1 million. Time was very precious on this job.”
Achieving such high production rates required excellent communication and coordination. Each of those weekends required two paving spreads, roughly 30 crew members, 45 haul trucks and traffic control.
Martin Marietta used Cat AP 1055F pavers and Cat CB15, CB44 and CB64 rollers, as well as Roadtec SB-2500C and Weiler E1650 shuttle buggies for the top lift of SMA.
Schmidt would talk to Paving Superintendent Justin Jordan two or three times per day leading up to those million-dollar weekends. “Jordan did a great job coordinating with the shop to make sure the equipment was ready to go, coordinating with the plant on tonnage orders, talking to QC,” Schmidt said.
They also had to contend with an intense quality control schedule. “With the sheer volumes we were doing, we had to make sure the quality assurance and quality control teams were in sync,” Norton said.
Schmidt would coordinate with Martin Marietta Quality Control Manager Jeremy Brassington after each million-dollar weekend to ensure he’d receive the results from the QA/owner by noon on Tuesday at the latest.
“Everyone on this project did a great job of holding one another accountable for communicating well and producing results,” Norton said.
The million-dollar weekends also required effective coordination with the prime contractor, to ensure they were ready for the paving crews on Saturday morning.
“Kraemer understands the production level we can achieve on a daily basis if they can ensure everything is ready for us,” Schmidt said. “That isn’t something you see on every project: the understanding of how much more work can be accomplished if everything is ready.”
Being able to have those big weekends was key to minimize impact on traffic, which was very important to the customer.
“The Authority is very concerned about keeping traffic moving on those roads, because the construction is funded by those tolls,” Norton said. “By working behind barriers on the widenings and doing the SMA paving on weekends, the traveling public wouldn’t see us on their commutes. They’d just see a big stretch of completed roadway come Monday morning.”
According to Norton, reduced traffic conditions during the height of the COVID-19 pandemic allowed Martin Marietta to increase its productivity by 15 percent since E-470 allowed for longer lane closure hours during that time.
Martin Marietta’s new asphalt plant, a 550-tph Gencor plant in Aurora, Col., also maximized production on the project. The 35,000 tons paved on the job in 2019 were produced at Martin Marietta’s asphalt plant on the west side of Denver, resulting in a 30-mile haul to E-470. The 135,000 tons paved in 2020 could be supplied by the new plant, located 5 miles from the E-470 project.
“The company invested in that plant because that part of town is growing so rapidly,” Norton said. However, he added, the E-470 job offered some immediate justification for the new plant. “The site of that plant feels like the middle of nowhere, but when we look at the jobs we are bidding and the development permits in that area, we will be right in the middle of that future growth.”
In total, the E-470 job required 165,000 tons of asphalt, including 60,000 tons of SMA. It was completed on schedule in October 2020.
Although the job does not offer a mix incentive, Martin Marietta ran a QPM to ensure the quality of the material–something they do on all large projects. “If there had been a mix incentive on phase one of the E-470 project, we would have gotten a significant incentive,” Norton said. “Although some projects don’t offer these incentives, I think it makes the customer happy to see that number and not have to pay it.”
The last phase of the project was recognized with a Best in Colorado quality award from the Colorado Asphalt Paving Association. Although it’s too early to tell, phase two could be a contender.
“Quality has been outstanding over the past two widening projects,” Brady said. “We have been getting 15 years plus from our SMA pavement, and we expect the same from the SMA placed by Martin Marietta.”
“Every project has a lot of moving parts, and it’s important to understand each other’s responsibilities,” Norton said. “Working with the same people just smooths out possible bumps that might happen when working with new people and new companies.”
He added: “Construction is all about relationships.”