By: Bill Wilson
Paving a 16-mile drag of I-97 outside of Baltimore, P. Flanigan & Sons Inc. must not have found the room to stick a wind sock.
The Baltimore-based contractor probably considered using the aviation device, because it thought of everything else during construction of one of the most physically demanding sections of construction in the region, if not the entire U.S. With traffic funneled down to just one lane at night and the influence of recreation off the Chesapeake Bay, the local medevac helicopter service kept its blades well-oiled.
“I can’t tell you how many nights I had medevac helicopters there [at or around the jobsite],” Glenn Snyder, project manager for P. Flanigan & Sons Inc., told Roads & Bridges. “When you shut them down to one lane, then they would get past the work zone and go 90 mph. I had cars in trees.”
Accidents put a clamp on progress on I-97 at a moment’s notice, but it took a lot less to power it down most nights. The Maryland State Police always had one arm resting on this time clock. If there was a threat of a traffic backup for whatever reason, P. Flanigan & Sons was ordered out. In an extreme case, operations had to cease because of an incident on the other side of the Chesapeake Bay, which was several miles away. The threat of a backup was just too real.
“They had that in writing because of where the job was,” said Snyder. “The only thing was once we were paving we couldn’t do that because of the hot asphalt. I had to make sure we had the asphalt right there and got going before [the police] came up and started talking to me.
“When there was a holiday I didn’t even attempt to work. If I had over a five-mile backup they could tell me to get off the road, wait an hour and then get back on it.”
Flanigan was able to roll with the stoppages and other obstacles, and in the end used effective strategy and an obscene commitment to quality to punch its ticket to asphalt paving immortality by winning this year’s Sheldon G. Hayes Award.
“We had a vision,” remarked Snyder. “We all sat down before that job started and we knew that it was going to be a tough job. We all knew it.”
Knowing is one thing, but success also rides on something else—execution.
Truck trials
Traffic control was only one of many challenging faces the I-97 project showed. Because it was close to the Seven River watershed, which is the main contributory to the Chesapeake Bay, officials and area leaders were concerned that oil from the road-building machines might spill into an environmentally sensitive area. With a staging area about 14 miles away, every night Flanigan used three lowboys to haul equipment to and from the work zone.
Timing took a front seat in this operation. If the lowboys ran late, the risk of getting stuck in traffic turned great.
“I had to have the three lowboys coming up with the closure so they could start working. At 7 we would put the lane closure out and by 7:30 we would have the equipment out on site,” said Snyder on the work window, which was from 8 p.m. to 5 a.m.
Trucks hauling asphalt also had to weave with efficiency through traffic. The Cedarapids asphalt plant was 33 miles away, which did not include the 12 miles the haulers had to drive just to turn around after emptying their load on the northbound section of the project.
Snyder estimated there had to be as many as 100 trucks working at one time, which required a ton of organization as well as an ounce of humor. On heavy nights, two truck managers were onsite providing direction. Ribbons on antennas indicated if one was hauling with base or surface course materials. Action turned so intense that the primary trucking company, L&J, Baltimore, had to call in other companies to help shoulder the load. That is when trucks began to wander.
“One night we are working and I knew the time the trucks were coming and they weren’t there,” recalled Snyder. “They went down Rte. 3 and kept on going forever.
“That was asphalt we had to throw away. The problem with all of these companies coming on board [with L&J] was nobody knew where they were going.”
If the lost trucks were roped in minutes into their scenic-route trip, asphalt just may have been salvageable. The first batches of the night dropped in trucks at 340°F, whereas the actual temperature at laydown was about 310°F.
“Our first loads of the night were traditionally our hottest, and the reason why we did that for our first couple of loads was because they would have to wait and the equipment was cold,” Philip Peters, asphalt paving manager for Flanigan, told Roads & Bridges.
Smooth all over
Temperature wasn’t the only element elevating on I-97. Quality and determination were at all-time highs. Before the ink was dry on the contract Flanigan was out coring the 16-mile section. A poor-performing open-graded asphalt mix—called “popcorn mix”—had to be completely removed, but nobody was sure on the depth of the pavement. It varied between 3 and 4 in. The cores helped crews pinpoint exactly how deep they had to go. The state, however, initially wanted the contractor to grind everything in one continuous motion. After seeing the inconsistencies in the cores, Snyder suggested chewing a few thousand feet at a time.
“It was between 3 [inches] and 4, and the state did not want to eat an inch of asphalt for the whole contract,” said Snyder. “I worked out different areas, and I would grind for a certain length at 4 and I would go a certain length at 3.”
Snyder also had a certain way of executing the grinding, and at the start of the job his expectations conflicted with those of Recon, York, Pa., the subcontractor hired for the first wave of work. Flanigan shut down Recon’s machine—an SSI High-Speed Profiler—for one week because of unsatisfactory results.
“[The grinding] was rough, and there was no excuse for it to be rough,” said Snyder. “Then they got onboard, brought in the right people and did a nice job.”
Flanigan was extremely sensitive to the smoothness specification. After Recon, which was grinding at 12½-ft widths, finished for the night, Flanigan brought in its own grinding machine, a Wirtgen W2000 armed with Topcon sensors in the front and back to ensure level work, to essentially sand down transition points in the lanes. The state called for 2½-in. drop-offs, but Flanigan cited safety issues and worked them down to 2 in. The contractor also took extra smoothness precautions around bridges and aimed at ending a night’s work at a span.
“When you take a grinding machine and you come up to a bridge and you zero out, say, within 50 ft, you have 50 ft to take out,” explained Snyder. “I went back 300 ft, pulled lines, shot grades and painted it out so I may be cutting a ½ in. all the way to 3 in. at the bridge. That gave me the perfect transition. I made sure it was smooth so our paver did not have to lift up. It went straight through.” To add insurance to their approach, Flanigan rode the job after the base course was placed. If it did not feel smooth, additional work was done—all at the cost of the contractor.
“Anything that didn’t feel right or didn’t show up right we fixed. We made sure it was smooth before we put our topping on. That was the secret,” said Snyder.
Flanigan did not pinch when mixing up its topping, either. Starting with the aggregate, some of the No. 7 rock used was larger than specifications, so the contractor screened the material to make sure all of it passed at ½ in.
“No one makes a No. 8 that meets that spec and no one makes a No. 7 that meets the spec,” Thomas Norris, quality-control manager for Flanigan, told Roads & Bridges. “We tried to get the aggregate people to make one that works, but they have to change everything over and it costs them a ton of money for one order of stone. No matter how big or little it is they won’t do it.”
Despite the state’s insistence on using 10% recycled asphalt in the surface mix, Flanigan refused to take a chance on quality and used all virgin material instead.
“I refused to do that,” said Norris. “I said I would get more RAP in the base but I am not bastardizing this mix for 10% RAP.”
Flanigan also tossed 0.3% cellulose fiber into the mix, which allowed them to add more of the PG 76-22 asphalt binder. The state minimum was 6%. Flanigan averaged 6.5% and again absorbed the extra cost.
“You have the most expensive product, which is liquid asphalt, and as an owner he will sit here and preach to us that we don’t have enough liquid in the mix,” said Peters.
“It is more expensive but it gives you the quality,” said Snyder. “I had one ramp that I wasn’t satisfied with and we milled it out and replaced it. There is no pay for that.”
There also was no escaping the tight restrictions of the job, not even out on the shoulders. The state required Flanigan to use millings from mainline work to form the outer portion. The contractor also could not exceed a 4-ft footprint, so truckers full of the older material backed up to feed a shoulder machine, which laid down the new pavement.
The Cedarapids asphalt plant, which often worked at a 350-ton-per-hour capacity, delivered the asphalt mix for the traffic lanes to a Blaw Knox MC300 material transfer vehicle, which transferred it to a Blaw Knox PF3200 asphalt paver. Four steel-drum vibratory rollers—two Ingersoll Rand DD-138s, one Ingersoll Rand DD-125 and one Ingersoll Rand DD-90—cranked out 4,000-6,000 vpm to work the mat to a desired density. In case of an unexpected breakdown, two DD-90s and a Blaw Knox PF200B asphalt paver were sitting 12 miles away.
After laying down a 19-mm Superpave partial-depth patching base course for repairs, a 9.5-mm wedge-and-lift Superpave course, which contained 15% RAP, and a 9.5-mm gap-graded Superpave surface course were worked in. To prevent premature cracking in the joints, Flanigan pinched in material to form a 1-in. overlay.
“The roller would stay off about a foot forcing the material into the joint, then as he is making his second pass he is forcing all of that material down,” said Peters.
The finishing roller also was responsible for pressing in inlaid pavement marking tape on the job. A dedicated quality-control manager monitored the rolling pattern and used a Troxler 640B nuclear gauge to check densities, which ranged between 93.08 and 95.20%. Air voids came it at 3.43-3.69%.
A profilograph was used to test for smoothness. The job averaged in the low 40s.
“Winning the Hayes means you have the best paving job in the country. I think everyone who was involved in it really believes that, that this truly was the best paving job in the country because of the quality in the end,” Pierce Flanigan IV, vice president of asphalt plants for Flanigan, told Roads & Bridges. “I don’t think you can set out to win this. You just win it.”
