Pouring it on

Michigan contractors unite to conduct record-breaking tunnel project

Paving Article December 28, 2000
Printer-friendly version

If they had wings they could fly. The airport was there, and at times the speed was certainly worthy of a takeoff.

But for hundreds of truck drivers, supervisors, operators and flagmen conducting the largest continuous one-day concrete pour in American history at Detroit Metro Airport, the whole idea was to get the job done underground, not above ground.

Executing a year’s worth of preparation, the crew was able to pour 21,000 cu yd of concrete to form the foundation of the 950-ft long North Tunnel along the airport’s new South Access Road on May 15. Amazingly, the mammoth project was completed in less than 24 hours—22 hours and 57 minutes to be exact. The job is expected to set a record for the most amount of yards pumped daily for a continuous concrete pour. General contractor Walbridge Aldinger sent a tape to the Guiness Book of World Records to make it official. The Hoover Dam averaged approximately 10,000 yd daily.

“Originally we figured to do it in 16 pours, and decided we wanted to do it in one,” Ken Beaudoin, vice president of the concrete division at Walbridge Aldinger, Detroit, told ROADS & BRIDGES. “We’ve poured a lot of large volume jobs before. . . you can only do the largest ever once, and it took a lot of planning but we were successful. I started dreaming this up about a year and two months ago.

“My intention was to set the record. It was just something internally, it’s just the challenge. But, as the man says, failure is no option. Once we committed to it we were going to do it, no matter what it took.”

In order to get approval from Wayne County, the airport and the Federal Aviation Administration, Beaudoin had to convince officials on the convenience of doing it all in one shot.

Once the pour got under way, a team of 40 inspectors from Wayne County’s field engineering office supervised the action to assure quality control. Aside from a minor problem with a concrete plant getting on line at the start, the operation went without a hitch, according to Wayne County’s Director of Engineering Kevin Maillard.

“By doing it once, and only once, they only had to live with it for 24 hours and that was it,” said Beaudoin. “And because we’ve done it in the past with them, we’ve done all the tunnel work from day one over there, they were convinced because we said we could do it. So with (the FAA’s final approval) we accepted the challenge and went for it.”

The team, however, wasn’t expecting another hurdle to be added to the race. The project was supposed to take place early in the year, when the demand for equipment and personnel is low. But sewer crossings had to be installed in the midfield terminal, pushing the start date back to May and the beginning of the busy construction season. Despite the delay, necessary resources were pulled together, which impressed Maillard.

“It was an incredible display of the coordination by the contractor and the concrete supplier,” he told ROADS & BRIDGES. “They had come up with a plan that they wanted to do, and they felt they could do it.”

The base of the tunnel, which is 150 ft wide and 4 ft thick and contains 1,700 tons of reinforced steel, is actually the first phase of the project which is part of a $144 million package. Pumping for concrete walls and a cover is scheduled for a later date. The 4-mile long South Access Road project will bring travelers into the airport from the south for the first time via Eureka Road and I-275 and take them beneath two active runways and several taxiways. The addition, which is expected to be completed in 2001, is expected to reduce congestion on the airport’s only existing public entrance, Rogell Drive, and aid Wayne County’s efforts to encourage new development south of the airport.

The pour presented new situations everywhere, but perhaps the one that stands out the most was how construction traffic was going to maneuver around airplanes coming and going. The record-breaking move began at noon on Saturday, May 15, and was completed at 10:57 Sunday morning. Air congestion during that time block was lighter than normal and one of the runways was closed for the operation, but there was still a heavy concern for safety, calling for hours and hours of planning and several dry runs.

On top of the countless number of meetings, Beaudoin also held a dinner for 300 workers, where he talked for about 2 1/2 hours telling everybody their job responsibilities.

“Safety was a major concern, and it was all done without any accidents,” he said. “We had flagmen, but everybody was totally safety conscious and we were careful.”

“We were smack dab in the middle of the airport,” John Formentin, vice president of Michigan Foundation Co., Trenton, Mich., told ROADS & BRIDGES. Michigan Foundation supplied the concrete. “You could see the passengers right through the windows. We were about 150 ft away from the wing tips of 757s.”

A fleet of flagmen were used to direct 150 concrete trucks (Oshkosh front discharge and International MTM mixers), which had to yield to air traffic, to and from the pour. The transportation process rumbled through without incident, and Formentin credits the flagmen, some of which were high-ranking executives.

“They could’ve made the wrong turn easily if they weren’t skilled,” said Formentin. “It wasn’t like we were pouring smack dab in the middle of the desert, this was an airport. The flagmen played very important roles to make sure everybody was on the right road.”

Six concrete plants—three at the airport and three off-site—were used to produce the concrete. The trio located about two miles from the pour consisted of an Erie-Strayer Combo 12, Erie-Strayer and a Coneco SLP. The Erie-Strayer Combo 12 was a dry mix plant, while the other two were central mix plants. There was a Ross-Johnson central mix plant and a Coneco PLP 12 dry mix plant located 4 miles off-site, and a 12-yd McNeilus dry mix plant located in Trenton 12 miles away. A seventh plant in Detroit was put on standby.

The mix contained a hefty total of 18,000 tons of aggregate, 15,750 tons of sand and 7,078 tons of Blue Circle cement. The pour, measured at a 6-in. slump, also contained 6,000 gal of an admixture called Euclid MR from Euclid Chemical. The admixture is a mid-range water reducer and allowed for a more fluid, pumpable mix. And because it was a non-air entrained mix trucks were not assigned a specific pump, which allowed the pour to go a lot smoother and faster than normal.

“When we’ve done mass pours like this before we could only have concrete trucks from a given plant go to one pump so we could control the mix,” said Maillard. “The fact that we had no air in the mix helped out. It allows you to pour a much more consistent mix and you could intermix the trucks a lot more easier because you weren’t adjusting admixture rates at various plants.”

The production capacity of the plants averaged out to a little under 1,000 yd an hour, according to Formentin, with peaks reaching 1,200 yd.

“Planning was the big thing, and we developed a team concept,” said Formentin. “We had constant dialogue with the contractor and the pumping outfit and it was a lot of fun. It was really done well.”

The curve thrown at the pump supplier, Cross Enterprises Inc., Melvindale, Mich., was how to reach a side of the placement which was being used by the airport. Booms could not reach all the way across the 150-ft wide placement, so delivery line and hoses were hooked up to some of the pumping machines.

A total of 13 Schwing pumps mounted on Mack 688S trucks delivered a pumping capacity average of 100 yd an hour. Three were Schwing 32 meters, one was a 36 meter, four were 42 meters, one was a 45 meter, two were 47 meters and one was a Schwing 52-meter pump.

“We work hard and this is something all the men who were involved are very proud of,” Cross Enterprises Executive Vice President Frank Feretti told ROADS & BRIDGES. “The placement isn’t anything, it’s the preparation prior to starting the placement to get all these people lined up. A lot of thought went into this prior to going up and putting it in there, so I give those people at Walbridge Aldinger a lot of credit. It made our job easy.”

“It has made us a lot better as a whole,” insisted Formentin. “We don’t have to brag, the project speaks for itself. This is definitely a badge of honor.”

About the author: 
Overlay Init