5R and ATL's New Fifth Runway

$360 Million Excavation Project a Model of Innovation, Safety

by Scott Judy

Some creative thinking has enabled joint-venture contractor 5R Constructors LLC to do something pretty incredible - mine, move and place nearly 25 million cu. yds. of embankment material for Atlanta International Airport's new Fifth Runway about six months ahead of its original 30-month schedule.

With a $350 million contract, plus potential for an extra $10 million in early-completion bonuses, 5R began mobilizing a fleet of more than 85 units of all-new Caterpillar equipment in September 2002.

That fleet size is even more impressive given that 5R's main method of moving material was a 5.5-mi.-long conveyor system. This method has proven to be the best - and really only - choice, providing huge time and cost savings over other alternatives and critical environmental and safety impacts as well.

Innovative Conveyor

When the project bid in 2001, 5R Constructors - comprised of C.W. Matthews Contracting Co., APAC-Georgia and Michael Thrasher Trucking, all of Atlanta - was the only bidder. A lawsuit was filed challenging the award, but a court-appointed arbitrator reaffirmed it in early 2002 after finding the city had attempted to generate as much competition as possible.

A major factor in restricting the number of bidders may have been the city's requirement that the bidder obtain some type of control over 27 million yds. of dirt.

Frank Nichols, president with APAC Southeast and a project executive with 5R Constructors, said the site the joint venture controlled was the only one that could work well with a conveyor system, and that hauling material with trucks from other sites to the runway would have been cost- and time-prohibitive.

The conveyor concept "sold itself," Nichols said. "It was high production, no pollution, no increase in traffic, no noise and it didn't do any damage to the roadways. And it moved the material faster than you could with any other means. It made it a win-win situation for everyone."

Partly because the use of the conveyor eliminated the need for many haul trucks - trucks that would likely be driving in or near traffic from offsite - the project has been a safe one without any serious injuries. In fact, 5R Constructors has won the Mine Safety and Health Administration's annual "Sentinels of Safety" awards two years in a row for being the safest quarry site in the country.

5R planned to convey the material from the mining/quarry site to several discharge bins located around the project. In addition to the length, the conveyor is unusual in that it travels through mostly well-developed areas, such as industrial parks, and over Interstate 85 and Georgia Highway 85.

While C.W. Matthews would be more focused on placing the material, APAC took responsibility for mining and loading it onto the conveyor. Minority partner Michael Thrasher Trucking assisted throughout the project.

Nichols said the company used three scalping plants, two stationary crushers and two more portable crushers to feed multiple loading points. The use of several loading points - as well as the numerous crushing units - illustrated the quantity that was required to keep on schedule.

"The production design is about 1 yd. per second," Nichols said. "(The conveyor) moves at about 800 ft. a minute, so it's going down the line."

The contractor used three Caterpillar 5110 mining shovels to initially excavate the quarry/aggregate material and then 10 Cat 773 65-ton haul units to feed it to the crushers. The scalping plants processed soil material.

Unloading

While the concept of delivering material by conveyor was not a novel one, the speed and quantities involved on this project were unlike anything the contractors had ever encountered.

"The real question was 'What do we do when this material gets to be filled and how do we take it off (the conveyor) and how do we place it?'" said Bill Hammack, managing director of 5R and executive vice president and COO for C.W. Mathews Contracting.

Prior to bidding, Hammack and others with 5R began looking at equipment options by utilizing Caterpillar's fleet production software program. They considered belly dump trucks, articulated trucks or rigid-frame haul trucks.

The team eventually opted to use 100-ton Caterpillar 777 rigid-haul units. With the considerations of cost and schedule, the 5R team figured that it could maintain the pace needed with just six trucks - if it restricted their travel radius to no more than 750 ft. and kept them repeating through quick loading cycles.

"If we could load one of those within 20 seconds, then we didn't need but six trucks (on the placement side) to build this job," Hammack said. "The trick was, how do you load a 100-ton truck in under 20 seconds?"

For that, 5R went to Astec Industries and told the manufacturer of material processing equipment exactly what it needed - bins that could contain enough material to discharge it into the 100-ton 777s in just a few seconds.

"The trick is, when those gates open, that material's got to come out," Hammack said, adding that the first truck loaded in a much-too-fast five seconds.

"That's not a good thing," he said. "(The 777) came off the ground from the impact. So we slowed down the opening of the (bin) gates a little (and) averaged about 12 seconds in loading a truck."

From there, the 777s drove downhill no more than 750 ft. - the discharge bins were always situated on a hill - and dumped the material, where a fleet of loaders, dozers, scrapers, motor graders, rollers and other types waited to move the material into place.

Significantly, the crews used no stakes to place the material. All dozers and motor graders were equipped with GPS units that assisted in controlling the grade.

"They know exactly how to cut the grade based on that information," Hammack said. "We're actually paid off of that GPS information. Very few stakes have been put on the job."

Placing

And there was plenty of material to move. The site of the future 9,000-ft.-long runway - which will span Interstate 285 when completed - was much too low. The average fill depth for 5R's contract was 90 ft., and it reached as much as 110 ft. in spots.

To meet the project schedule, the 5R team needed to keep the material moving nearly seven days a week. The contractor was mostly able to do this - even during an exceedingly rainy 2003 - despite the material being made up of a considerable amount of Georgia red clay. The construction team was able to do that because between 25 and 30 percent of the material is rock.

"With the weather conditions, that (rock) turned out to be a real blessing for us, because we were able to adjust the percentage of rock and run when a traditional project would have to shut down," Hammack said.

During the wet and cold weather, Nichols said, "We were mixing rock and soil together the whole time to try to keep a flowable mixture. (Some days) it was like either rocky dirt or dirty rock that we were running."

The project specifications were such that 5R simply had to deliver material that was no bigger than 7 in. in size (or "minus 7-in.") and meet the moisture and density requirements. "We were able to selectively switch from say 80 percent minus-7-in. (rock aggregate) to maybe no minus-7-in. material, depending on weather conditions," Hammack said. "So we maybe wouldn't ship any rock when we had long dry periods and simply load dirt."

Nichols added that because of the versatility of the design, work could continue through the winter. "Of course, if you can run a full rock fill, you can make a wonderful product," he said. "But you have to run enough dirt to fill the voids, and that's what we were demonstrating we could do."

The top 7 ft. of the embankment will contain mostly dirt.

Innovative Equipment Monitoring

Another innovative part of this project can be found in the equipment running around the site. Made up almost entirely of new Caterpillar construction and mining units, the 5R fleet represents a capital investment of more than $30 million - and was a critical component to keeping the job on schedule. Many of these units, such as the 777s and D10 dozers, couldn't be replaced easily because they are so large that they are shipped from the plant in pieces, on several tractor/trailer loads.

To keep them up and running, 5R Constructors entered into a partnering agreement with Caterpillar and Yancey Bros., the Atlanta-based Cat distributor. Caterpillar would supply the equipment and Yancey Bros., working onsite and utilizing state-of-the-art satellite-based monitoring equipment, would manage and service the huge fleet.

Yancey Bros. was able to keep track of the most critical data about each machine.

"They could tell if we had an engine running hot, a transmission slipping - they could even tell us if we had a driver incorrectly shifting the transmission," Hammack said. "It was amazing. They really minimized the downtime of the equipment."

The bottom line, of course, is that this contract is turning into a huge success story - on time and under budget. 5R's Hammack said the team expects to conclude its work and be completely demobilized by Christmas. The original "early" completion date was June 27, 2005.

Airport officials are highly pleased with 5R's work to date.

"5R's performance has been very impressive," said Ben Decosta, airport manager. "The innovative use of the conveyor has exceeded the expectations of all associated with the project. Additionally, we have been impressed by their attention to detail, such as special maintenance programs necessary to keep the conveyor and the fleet of construction equipment operational, and their willingness to address public concerns pertaining to temporary construction impacts."