Because Walsh Construction is new to the Indianapolis, IN, area, the Chicago, IL-based prime contractor that specializes in structural concrete work is relying heavily on subs for the I-65 project through Indianapolis. “We specialize in earthwork, sewer, retaining walls and bridges, and concrete paving,” said Project Manager Arik Quam. “But we didn’t have enough staff or confidence to do all the work ourselves this time.”
For the slipform concrete work, Walsh turned to an expert and familiar subcontractor, CRI Construction of Larwill, IN. Chris Whitehead, vice president and founder of CRI, said, “Walsh is out of Chicago and La Porte. We’ve subbed for them up there a lot. Everything just fell into place, and we followed them down here. Besides this project, we’re subbing for them on four or five other jobs right now.”
CRI Construction was founded in 1990. Located in the northeastern part of Indiana near Ft. Wayne, the company bids a lot of jobs in the northwest region of the state. “That part of the state is more industrialized,” Whitehead explained. “Plus, with Chicago and the casinos up there, the state likes to keep the roads in good shape.”
With a staff of around 30, CRI specializes in slipform work, but also performs concrete flat work and small road projects. “We slip anything,” Whitehead noted, “from sidewalk curbs to big walls. We even slipped a pad for a commuter train to Chicago.”
The I-65 project calls for some of the tallest slips recorded, and CRI is just the contractor to make it work.
Project Overview
The two-year project entails adding lanes and widening existing lanes on Interstate 65, its overpasses and on- and off-ramps. One lane will be added to I-65 in each direction from downtown Indianapolis northwest beyond the I-465 ring road. Having three lanes of traffic in each direction is expected to greatly assist rush hour traffic snarls for the rapidly expanding commuter workforce in the city.
The work also involves widening on- and off-ramps along the I-65 corridor, in conjunction with Capitol Asset and the city of Indianapolis, and making improvements to the overpasses. Erin Beikman, of the Indiana Department of Transportation (INDOT), said that a total of 19 bridges will undergo improvements.
The $88-million project is an A plus B contract, with three distinct incentive packages for early completion. Although the contract granted approval for work to take place seven days a week, 24-hours a day, Beikman stated that INDOT insisted that the construction crews get at least one day off per month, and have specified certain dates throughout the year as non-work days.
Quam said the crews are working six days a week, with little shift work. “They’re working some nights,” he explained, “due to lane closures that require hours of less volume on the highway, but there’s not much night work.”
But Quam assured, “We pursuing an aggressive schedule.”
However aggressive Walsh intends to be, the completion date is slated for more than a year away — November 2001 — due to a winter layover. Phase I extended from June 28 through Nov. 15, 2000. The stated purpose was to rehabilitate the pavement and bridge structures on northbound I-65, the outside lanes on westbound 38th Street and the inside lanes of eastbound 38th Street. The Cold Springs Road and eastbound 38th Street bridges were replaced.
Northbound traffic was crossed over to the southbound lanes of I-65 to just south of Cold Springs Rd., with a single 10-ft. (3 m) lane of traffic flowing in each direction. Quam elaborated, “All traffic was in the existing southbound lanes while we constructed the north-bound lanes. Next year, the southbound traffic will be moved to the new northbound lanes while we reconstruct the southbound lanes. But it will be easier for commuters next year because they will have two lanes in each direction.”
Winter layover began Nov. 16 and lasts through Race Day in May. Northbound traffic will have three new lanes, while southbound traffic will continue with two.
With the resumption of work under Phase II, traffic will be shifted to the northbound lanes to allow construction to progress on the southbound pavement and bridges, the inside lanes of westbound 38th Street and the outside lanes of eastbound 38th Street.
Slipping Fast
Whitehead said that even though his crews just started the first week of August, he expected to get 70 percent of their part done in 2001.
CRI crews wrapped up Phase I work in 2000. They completed about 6,400 ft. (1,951 m) according to Marvin Whitehead, Chris’ father, and will finish another 2,000 ft. (610 m) in 2001.
The younger Whitehead calculated that 800 to 1,200 ft. (244 to 366 m) of wall is about a day’s worth of “normal wall” — at a height of about 6 ft. 7 in. (2 m). But some sections of the wall top out at more than 8 ft. (2.4 m).
“We can only do about half as much with the 8-ft. wall,” Whitehead noted. This calculates to about 480 ft. (146 m) per day. About 500 yds. (139 m) of footer can be slipped per day. Of course, many factors contribute to the speed with which they can work.
“Rain stops us,” said George Dockery, operator for CRI. “Especially with the footers.”
Then there’s the issue of concrete, which is supplied by Prairie Group. Dockery explained that some mornings the drivers were waiting on them to show up, and other mornings, the crew was left tapping their collective foot, waiting on concrete.
Dockery said he goes through a truckload of concrete in about 10 minutes. “I can go about 17 ft. on the big wall, then I need a new truck,” he stated. If that next truck isn’t ready and waiting, problems can arise. “If you wait too long [before pouring], it starts to set. Then you have to jackhammer it out of the machine. The mixture has to be just right. The concrete has to be perfect or it will fall off. We like to pour thick — what we call low clump of about an inch.”
Once it arrives, Dockery said concrete is “fickle.” Impurities in the mixture cause the slip to crumble and fall, which has happened to the CRI crew at least once. That delays progress, because the concrete has to be cleaned up and the wall re-slipped.
The Process
A footer is poured and hand-formed along the path where the median wall will take shape. Six ft. (1.8 m) wide, it is about 32 in. (81 cm) tall, with a 28-in. (71 cm) groove in the middle to support the wall. Rebar struts protrude from the footer, to which more rebar is tied to form the shape of the wall. Great care is taken in the preparation, because, as Dockery said, “If the tie-wire leans, the wall has a tendency to lean, and maybe to crack.” To help ensure that the wire is straight, he fabricated an angle iron on the Gomaco GT 6300 Commander 3 to “push the wire straight.”
Measurements are taken off the footer and the constant grade stake for a guide string. That thin string will be read by the Gomaco. Steering arms front and rear, as well as grade arms front and rear, stay on the string, following its designated path. “There’s a computer on board that tells us how to pour. It’s all automatic,” Dockery noted. “It tells us how many variances there are, and where to start them.” On one side of the median wall, there are four variances.
A concrete truck follows alongside the Gomaco. Concrete is conveyed into a hopper, then released into the mold — which weighs 20,000 lbs. (9,072 kg) empty. Fifteen vibrators in the mold compact the green concrete, which takes shape along the rebar forms.
“It’s not a high-speed deal,” chuckled Dockery. “Sometimes you don’t feel like you’re moving at all.”
Right behind the Gomaco are two brothers whom Dockery calls some of the best finishers in the business. “They tell me ’don’t worry about it — you just get it to stand, we’ll take care of it,’ ” he said. They brush the wall, smooth the top and fill in if there are any air pockets, but he added that the stainless steel mold is kept so clean that the concrete slips out of it very well, rendering patch and fill work almost unnecessary.
Following at a fair distance behind the finishers, a crewman sprays the wall with white pigment to help it cure. Two to three hours later, they saw a wear crack every 30 ft. (9 m), for expansion during freeze and thaw cycles. It takes three days to fully cure, but Chris Whitehead said that within a day the wall is strong enough to do anything to it.
Tall Slips
INDOT mandates a minimum height of 46 in. (1.2 cm) for median walls through an inner city with on-coming traffic. Due to the uneven and varied level of the two directions of traffic, CRI has to slip walls more than 8 ft. (2.4 m) high along some stretches of I-65.
According to Chris Whitehead, the previous height record for slipped walls was 84 in. (213 cm). He added that it has a pyramidal base and shape, whereas the wall they are slipping “is a difficult profile. It’s vertical, up and vertical again. It’s a variable wall — higher on one side than the other, and most of it is straight up.”
CRI slipped walls on this project at a height of 103 in. or 8 ft. 7.5 in. (2.6 m). “Everyone said it couldn’t be done, even Gomaco,” said Dockery. The manufacturer sent representatives to the job site to view and record the new feat. The 8.5-ft. (2.6 m) walls even attracted the attention of a local TV news film crew.
Pride in a Job Well Done
As Dockery stated, “It’s not high-speed work. Weather, concrete supply, wet holes in the ground and other numerous obstacles can slow the work. Although CRI keeps to its schedule, it doesn’t try to rush the work to make up for time. Cleanup takes at least half an hour every night, using jackhammers to loosen set-up concrete lodged in the mold. Crewmen wipe down the inside of the mold until it shines. Footers are cleared of debris in preparation for the next day’s work. The finishers expend enough care in smoothing out the wall, you might think they were working on the drywall of their own new house.
“You’ll never know it when you’re driving down the road at 65 mph,” said Dockery. “But WE know it. We’re craftsmen, we take pride in it.
“It’s all Marvin’s ever done. There aren’t a lot of slipform specialists any more, and he’s the best at it. He cares about his work, about doing a good job. You’re not going to get called to do any more work if your wall falls down in a year or two. So even though you might not see the care and detail we put into it, it makes a difference,” he added.
Marvin Whitehead’s wife sums up the attitude of CRI and the approach the whole crew takes, “Isn’t it beautiful?” she said. “Look at them — they’re like sculptors. It’s really beautiful to watch.”
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