Producing and paving 9,000 tons of asphalt over the course of a weekend is no easy feat. Doing it for eight weekends in a row is impressive. Maintaining quality, achieving a smoothness bonus, and receiving an “Excellence in Program Delivery” award from the Colorado Asphalt Pavement Association (CAPA) for such a project is astounding.

But that’s exactly what Kraemer North America and Martin Marietta, as general contractor and paving subcontractor, did on an 8-mile job along E-470.

Located in the southeast Denver metro area, the project extended from around mile marker 5 to mile marker 13, between Parker Road and Quincy Avenue.

Although the end result of this project was the addition of a third travel lane in each direction, Kraemer and its subcontractors also performed the grading, earthwork and drainage needed to eventually add a fourth lane of travel in each direction for a total width of eight lanes. The project also included widening 11 bridges and three overpasses.

“For those 8 miles, we’ve done all of the work for those additional lanes except the paving,” said Jim Brady, Construction Manager for the E-470 Public Highway Authority. “Right now, we’ve got that projected for 2032 in our master plan.”

The genesis of the project was a traffic and revenue study the E-470 Public Highway Authority performed to track current traffic trends and projected traffic growth. Last year, traffic on the highway increased around 5 percent, and for the three years prior, traffic growth percentages were increasing in the double digits.

“The study determined that we’d start to see our level of service drop to a D by 2018 for that stretch of the highway,” Brady said, “and we’d start to lose service due to traffic volumes.”

The Authority made plans to rectify the issue.

Felsburg Holt & Ullevig began designing the project in early 2015, and construction began in spring 2016 with Kraemer as the general contractor and Martin Marietta performing the asphalt production and paving.

Kraemer’s Project Manager Michael Fay complimented Martin Marietta, with whom they’ve worked before, on their performance on the job.

“They were right there for the planning, scheduling and getting things done in large volumes week to week,” Fay said. “We were able to complete the job early because of what they brought to the table in terms of the amount of asphalt they could provide and the crew, equipment and resources they had available.”

Paving E-470

Martin Marietta’s West Plant in Golden, Colorado, produced more than 200,000 tons of asphalt for the E-470 job, including 130,400 tons of hot mix asphalt (HMA) and 76,000 tons of stone mastic asphalt (SMA).

The HMA used was S 64-22 with 20 percent RAP and was paved in three lifts of 3 inches each, for a total of 9 inches, placed on top of cement-treated subgrade.

“Our entire roadway is built on full depth asphalt on cement treated subgrade,” Brady said. “It was a business decision we made when we first started construction so we didn’t have to work around having a mix of concrete and asphalt. Asphalt gives us more latitude to keep the road surface in good condition.”

On top of the 9 inches of HMA, Martin Marietta placed two inches of SMA. Having used SMA on E-470 overlays for years, it made sense for the expansion.

“We started using stone matrix asphalt back in 2004 and it’s proven to be a hardy wearing surface,” Brady said. In fact, the section of roadway they just widened was the first section the Authority had ever used SMA on. “That’s going on 14 years and the existing wearing surface was still in good shape.”

Ever forward-thinking, though, the Authority did decide to overlay the existing roadway with a new lift of SMA.

The 2-inch SMA surface course was paved in a single lift with two Caterpillar 1055F pavers working in tandem to pave 24- to 26-foot-wide passes.

Instead of paving the surface course at night, as it was bid, Martin Marietta suggested employing echelon paving on weekends to improve safety, speed up the project and reduce visible joints on the project. In fact, there are only two joints across the entire six-lane highway.

Bid as a construction manager/general contractor, or CM/GC, project, the contractor and subcontractors were able to bring new ideas like this one to the table early in the design process.

Why CM/GC?

Although the CM/GC delivery model is gaining popularity–in fact, Kraemer will be doing a CM/GC job for CDOT on I-25 later this year–this was the first time the E-470 Public Highway Authority has ever bid a project in this way.

“CM/GC is a method of project delivery that’s getting some traction,” Brady said, adding that CDOT has used it numerous times over the last six years, as have other state agencies. Kraemer has quite a history with CM/GC projects, Fay said, adding that they performed their first CM/GC project in 2004 for Vail Resorts.

For this project, the E-470 Public Highway Authority hired the design firm Felsburg Holt & Ullevig to complete around 30 percent of the design before advertising the job for bids from general contractors. The Authority then selected Kraemer North America as the general contractor for the project based on merit, with a cost element. From then onward, Kraemer worked alongside the design firm to finish the plans.

“A design firm knows how to put things on paper that will work, but they don’t always know if that’s the best way out inp the real world,” Brady said. “If we have the contractor involved at that part of process, they bring a different set of eyes early on and can help save money and to accelerate the project.”

And accelerate they did. Brady credits finishing the project a few months early to the ability to get started without a 100 percent complete design.

“If we tried to fully design the project and then advertise it, we’d have been waiting a long time to get the full bid package out,” Brady said. Instead, they broke the project into phases and were able to complete everything a few months early, in October 2017.

By dividing the project into multiple packages, Kraemer was able to begin work in May of 2016 and get a third travel lane open for a portion of the project by the fall and alleviate some of the anticipated construction congestion the overlays would cause.

With Kraemer coming in under the initial budget for the job, the Authority was also able to add another bridge widening, two ramp reconstructions, retaining walls, and enhanced aesthetic features to soften the effects on nearby residents and businesses.

One specific example of the CM/GC process in action was when Kraemer’s subcontractor for the cement treated subgrade noticed that some areas were below the strength requirement of 200 pounds per square inch.

According to Kraemer Project Manager Michael Fay, the subcontractor started increasing the amount of cement to try to increase the strength of those areas, without a significant increase in the strength despite the added cost and effort.

“That was during the early work in package one, so we continued with the added effort and cement in order to meet our milestone,” Fay said. But then, over the winter of 2016 into 2017, Fay and his team researched cement treated subgrade and met with industry experts to come up with a new game plan that met E-470’s goals, but offered the contractors more flexibility. E-470 would allow for more range within its strength requirements and would pay for the additional cement itself.

In this way, the CM/GC process also reduced risk.

“If you let a project, all that risk is on the contractor and he has to price his work almost assuming a worst-case scenario,” Brady said. “This way, we made those risks separate pay items so if, for example, we don’t get a lot of rain holding up work, the Authority gets to keep those dollars.”

CM/GC identifies all risk elements and allows the team to discuss how to allocate and share the identified risks.

“I think E-470 appreciated the open-book nature of the CM/GC environment,” Fay said. “Kraemer and our subcontractors share pricing and we’re always open to a better way to do things. You’re truly getting the best value at the end of the day.”

“The concern with CM/GC is that you lose the competitive pricing,” Brady said. However, that wasn’t the case for this project.

“Competitive bidding was maintained through getting numerous quotes on all disciplines of work outside of the bridge structures,” Fay said. “Kraemer used an open-book approach for the bridges and compared this pricing against the independent cost estimator and the engineer’s estimate.” Kraemer also received multiple bids for all sub-contracted work, allowing E-470 to make “best value” decisions on all elements of work.

However, Brady realizes CM/GC might not be right for every project. For example, he said, a simple project might be better-suited to put out a set of plans and receive competitive bids.

“[For this project], we wanted to be more in control of the risk elements, construction phasing, and traffic management for the project,” Brady said, which made this job a good candidate for CM/GC.

“For some people, it’s a bit of a mental shift on how to handle problems when they come up,” Fay added. But, for the right job and the right team, CM/GC might be well worth the mental shift.

Keep Traffic Going and Customers Happy

According to Ryan Yoch, General Manager of Martin Marietta’s Rocky Mountain Division, all the bottom lift paving was performed mainly on weekdays behind barrier, with minimal impediment to traffic. Two lanes of traffic in both directions were kept open during weekday morning and evening rush hours. The speed limit was only reduced to 65 mph rather than 75 through the construction zone.

However, Yoch said, paving the surface course would impede traffic to a larger degree, so a new plan of action had to be established.

E-470 is composed of eight local member governments: Adams, Arapahoe and Douglas counties, and the municipalities of Aurora, Brighton, Commerce City, Parker and Thornton. As a separate entity from CDOT, the E-470 Public Highway Authority receives no state or federal funds. Instead, the Authority is entirely self-funded through tolls. As such, they were very concerned about drivability throughout construction.

“We’re a toll road, so our drivers are our customers and our customers generate our revenue, so customer service is a constant theme of the project,” Brady said. “Allowing them to do tandem paving on the weekends was a bit of a struggle for us because it did create more congestion, but it also allowed us to get done much quicker. A big benefit of doing CM/GC was making traffic management a team effort.”

“E-470 is always very concerned about their customers—the driving public,” Yoch said. “But you also have to make sure it’s still safe for your employees to be on the road.”

Fay considers the cooperation of the various stakeholders to be one of the major successes of the project, making coordination and traffic management as frictionless as possible. “They saw we were doing all we could to minimize impacts to them and were great partners to help move things quickly and safely,” he said.

The Authority ultimately allowed Martin Marietta to close down to a single lane on Saturdays and Sundays to pave the surface course.

In addition to the increased safety of paving on the weekends versus at night, this also helped Martin Marietta more easily bring two crews to the job.

“We could be safer and faster and get rid of two cold joints on the project,” Yoch said. “It was a win all around.”

Martin Marietta was able to pave the surface course of the third lane and the overlays—a total of 64 lane miles (including 12-foot shoulders)—over the course of eight weekends. Their average paving speed was 25 feet per minute, paving eight lane miles each weekend or 2 miles per weekend in one direction, covering one 12-foot shoulder and three 12-foot driving lanes.

Maintaining this pace wasn’t only a challenge on the job site, but also at the asphalt plant.

“We’ve worked with Kraemer on a few jobs over the past couple of years,” Yoch said. “I think they knew our potential, but they really saw a lot more of it when we got fired up on this project.”

In fact, Martin Marietta nearly doubled the production they committed to Kraemer upon award of the project, completing around 9,000 tons over each weekend they paved SMA.

“Even some of our competitors called and complimented us on a job well done,” Yoch said.

To hit those numbers, Martin Marietta used its 750 ton-per-hour Astec double drum plant—the largest double barrell plant in the world, according to Yoch.

“It’s nice to open her up and let her run,” Yoch said, “but it was a grueling two days to get that volume at a high quality without many issues.”

However, Yoch adds, it’s less about the iron than it is about the people.

“Of course you need the equipment, but it’s really our employees who make it happen, from scheduling the trucks to loading them to the guy running the plant and the guy running the paver,” Yoch said. “It took everyone’s hands to make this project a success.”

Although it was challenging to maintain smoothness and quality at those volumes, in the end Martin Marietta was able to hit its smoothness bonus for around 85 percent of the money available. “If there had been a quality bonus, they would have been writing us another big check,” Yoch said.

To help achieve smoothness and quality, Martin Marietta used its Roadtec shuttle buggy to remix asphalt on the job and prevent trucks from bumping the paver for maximum smoothness. To load the second paver, they rented a Weiler E1250. The crew ran three CAT 534 double drum vibratory steel wheel rollers and two CAT 634 vibratory steel wheel rollers to get compaction.

Another challenge to obtain smoothness was that Martin Marietta didn’t do any milling on the old highway before paving the SMA overlay. Instead, they identified some of the larger bumps or dips and performed some bump grind milling to maximize the smoothness E470 expects.

“At the end of the day, that’s why they like us because we go the extra mile,” Yoch said.

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What is CM/GC?

Construction Manager/General Contractor, or CM/GC, is a project delivery method where the contractor acts as a consultant during the initial procurement phase of the project.

“It’s kind of like an arranged marriage,” said Colorado Department of Transportation Innovative Contracting Program Manager Nabil Haddad. “The contract is between the owner and the contractor and the owner and the consultant. There’s no contract between the contractor and the designer.”

The owner or agency hires the contractor, who works alongside the internal design team of design consultants, to help with the design, look at the risks, assist with scheduling, identify opportunities for innovation, and work through constructability issues.

“Consultants and designers usually appreciate having someone with construction experience help with design,” Haddad said.

CDOT has utilized CM/GC on 14 projects since it began using the project delivery method in 2011. In fact, CDOT just selected Kraemer North America for a CM/GC project on I-25 between Castle Rock and Monument.

How CM/GC Works

Haddad recommends hiring the contractor as early in the design process as possible. For their last handful of projects, CDOT brought in the designer and contractor at the same time.

“We’ve done it both ways, but the earlier you hire the contractor, the better,” Haddad said.

For example, in the case of the project on E-470, the E-470 Public Highway Authority hired the design firm Felsburg Holt & Ullevig in March of 2015. After the firm completed around 30 percent of the design, the authority began advertising the job for bids from general contractors before selecting Kraemer North America based on merit with a cost element. That way, Kraemer could offer its expertise throughout most of the design process–like, suggesting that the design firm divide the project into multiple phases to allow Kraemer to begin work in May of 2016 and finish the project a few months ahead of schedule, in the fall of 2017.

Haddad said that once the design approaches 90 percent completion, the contractor gives a price for the project. Then, the owner or agency negotiates on that price until it falls within a pre-agreed percentage of the cost estimate–usually 5 percent. “It looks more like design-bid-build after that,” Haddad said.

According to E-470 Public Highway Authority Construction Manager Jim Brady, one concern with CM/GC is that agencies will lose out on competitive bidding. However, to ensure that cost remains competitive, Haddad said the costs provided by the contractor are checked against CDOT’s own estimates, as well as those of a third party independent cost estimator, or ICE.

“We compare three estimates, from the contractor, CDOT and ICE,” Haddad said. “Everything is open and we publish those numbers at the end of the project.”

“There are some contractors in town who are leary about CM/GC because they aren’t used to it,” Haddad said. “We’ve been talking to them and engaging with them, and, little by little, they’re realizing the value of this delivery method and how beneficial it is.”

Additionally, CM/GC can save money in some cases by reducing risk. The CM/GC process allows everyone involved to discuss potential issues, identify ways to mitigate risks, and assign financial responsibility for those risks, should they arise.

“If you look at CM/GC nationwide, all the agencies who’ve used it see reduced overall risk,” Haddad said, adding that you can break down risk into different categories: owner risk, contractor risk, and overall risk. With design-build, the risk is usually transferred from the owner to the design-build team, Haddad said, and with design-bid-build, the risk is normally on the owner. “CM/GC typically lowers overall risk because the owner, designer and contractor work collaboratively to reduce risk from the start.”

In the event of unforeseen issues, the CM/GC project delivery method also allows for risk pools.

“For example, we might put $200,000 into a risk pool in case we run into soft soil,” Haddad said. “If we run into those issues, we can share that cost. And, if we don’t experience those risks, we can split the balance of the risk pool. Contractors love it because they can find innovative ways to save money.”

When to Use CM/GC

To decide which projects to utilize CM/GC on, CDOT uses a risk-based matrix to determine the best delivery method for each project. Although there are a lot of factors to consider, Haddad said, most of the projects for which CDOT uses CM/GC are high dollar value projects. “$90 or $130 million,” Haddad said. “A couple have been $20 or $25 million.”

In addition to cost, CDOT looks at several other factors, including project schedule, innovation opportunities, third party agreements, risk, and level of design.

“If the level of design is too high, say 80 to 90 percent designed, CM/GC probably won’t work since there isn’t enough flexibility to change the design,” Haddad said. Oversight is an additional consideration. “Do we want to let them run with it, or do we want to have more say as an owner? If we aren’t ready to relinquish a lot of control, CM/GC is a better method.”

“We also use CM/GC if there is a lack of experience at the department,” Haddad said. “For example, we had a tunneling project and the last time we’d done that was in 1972 with the Eisenhower Tunnel.” So, the project team brought in a contractor from Japan with tunneling experience and employed CM/GC on that project, as well.

“You have to have the right project, the right personnel and the right reasons to use this method,” Haddad said.

The Future of CM/GC

Despite its benefits for some projects, the CM/GC concept is fairly new to the U.S., with Utah being an early adopter of this project delivery method around a decade ago. According to Haddad, CM/GC began picking up momentum three or four years ago.

“There’s definitely interest in it,” Haddad said, adding that he’s received calls from DOTs in Nevada, Massachusetts, Maine and Louisiana. “It’s not declining. It’s still a tool in the toolbox and it’s not going away.”