E&B Paving Builds Heavy-Duty, 292-Foot Tunnel in 92 Days at Louisville International Airport
To minimize disruptions at the Louisville International Airport during the $18.8 million Runway 11-29 Safety Area Improvement Project, prime contractor E&B Paving, Inc., of Anderson, Indiana, completed most of the job in a tight 92-day window last summer. The work included the first blasting at the airport in decades, a 292-foot tunnel with 53 arches weighing over 27 tons each, strict security measures from the Transportation Security Administration (TSA), and many other challenges.
By the end of the project, crews excavated 56,736 cubic yards of material and replaced it with 65,119 tons of aggregate, 17,181 tons of bituminous asphalt, and 18,473 yards of Portland cement concrete pavement. In addition, E&B oversaw specialty subcontractors placing over 2,000 blocks for a unique Engineered Materials Arresting System (EMAS) at the end of the runway.
The Louisville International Airport offers three runways. Most commercial aircraft use the two that run north/south. Runway 11-29, one of the few remaining features of the original airfield, is shorter than the other two and used less frequently (when winds shift east to west). This project ensured that the Runway Safety Area (RSA) at the end of Runway 11-29 complies with federal standards for safety if an aircraft overshoots the main runway.
Because there wasn't enough space between the end of Runway 11-29 and the airfield security fence to add the standard 1,000-foot RSA, the airport opted for the EMAS alternative. "It's like a LEGO block run-off area," said Bob Sallee, E&B's Project Manager. "Its goal is to be non-destructive to the aircraft yet arrest its motion."
Similar to runaway truck ramps made of gravel or sand, aircraft tires sink into the crushable EMAS blocks to smoothly decelerate, keeping passengers safe and minimizing damage to the plane. Zodiac Arresting Systems America in Logan Township, New Jersey, engineered the blocks. Made of lightweight cellular cement, each block measures approximately 4 feet square and weighs up to one ton.
Boland's North Inc. from Conklin, New York, installed more than 2,000 EMAS blocks in a graduating stepped bed. Forklifts maneuvered the blocks into position while crews placed spacers, hot poured a bituminous mastic, then secured each block in place.
Rare Blasts and Heavy Arches
Since the new RSA extends over the airport's existing Perimeter Road for service vehicles, project engineer HNTB, with collaboration between their Louisville and Chicago offices, designed a tunnel to run underneath the EMAS and reroute the road.
To reach the desired depth for the tunnel, crews blasted through approximately 9 feet of solid rock. "In the 40 years I've been in construction, I can't recall a time the airport allowed blasting on-premises," Sallee said.
Crews used a controlled, small-charge blasting process. To muffle noise and contain debris, they covered the charges with dirt and explosion-suppression blankets.
Before blasting began, the airport warned tenants in the terminals and private hangars, as well as surrounding businesses. "They wanted to let them know that if they heard a little rumble at the airport, there was no need to worry," Sallee said. To further minimize concerns, "We tried to blast at the same times every day."
The airport invited local utilities and other interested parties to observe the blasting. "We had quite the group the first time, but it was really a non-event," Sallee said. "Once the first blast was completed, successive blasts received little attention."
After the excavation, crews poured 10-foot-tall cast-in-place walls on spread footings. To form the roof of the 292-foot-long, 30-foot-wide tunnel, Contech Engineered Solutions in Louisville supplied 53 precast concrete arches, each weighing 27.6 tons.
Extensive engineering collaboration ensured structural strength. "The EMAS block system is right over the top of the tunnel," Sallee explained. "If an airplane comes through there, when it comes to a stop it'll be right over the tunnel. These precast concrete arches are designed to support an aircraft."
To ensure the tunnel remains passable no matter the weather, E&B's subcontractor, TSI Paving of New Albany, Indiana, constructed a 26-foot-deep wet well with 24-inch thick walls. Three pumps work in succession to route water into the airport's main drainage system. The back-up Kohler generator includes numerous automatic controls to sense any power disruptions.
92 Days to Takeoff
Construction of the tunnel, as well as runway pavement replacement in several of the aircraft-affected areas, occurred within the 92-day window. "Historically they experience the least amount of crosswind issues in June, July, and August, so that was the least likely period that Runway 11-29 would be called into service," Sallee said.
The project team met schedule targets for the various construction phases thanks to extensive planning and the Louisville Regional Airport Authority's partnering effort, Sallee said. Had they missed those deadlines, they would have faced severe penalties. "For instance, we were subject to a penalty of $5,000 per day on most phases of construction with some sub-phases penalized at $5,000 per hour if we didn't get them completed and open."
Phase 2 of the project, at an intersection in the center of the runway, presented one of the toughest challenges. "It was the only portion of 11-29 still in asphalt," Sallee said. "Even though they worked on other areas of the runway over the last 20 years, because that intersection is so critical to UPS and other aircraft operations, they were reluctant to take it out of service for anything more than asphalt repairs."
In this project, "That was a 30-day wonder," Sallee added. "They shut the runway down in June and we performed a remove and replace. We had to excavate several layers of improvements they had done over the years. In that intersection alone, 8,775 square yards of asphalt came out and the same amount of concrete went back."
During Phase 2, E&B also added 35-foot paved shoulders with edge lighting on both sides of over 4,000 feet of the runway.
Meticulously Safe and Secure
To access the Phase 2 work, crews had to travel across active aircraft movement areas, which required official airport escorts. "The escorts met us at one of the security gates," Sallee explained. "We traveled on the Perimeter Road, then when we reached an active aircraft movement area, they'd hold for a moment and call the tower. When they received permission, we all promptly moved forward and proceeded straight to the construction area. That threw a little curveballyou couldn't just come and go as you pleased."
For pavement replacement on the east end of the runway, the airport closed portions of a taxiway so contractors could directly access the work area. At the west end, "Portions of runways were closed at times to facilitate the construction," Sallee said. "The airport authorized closures with the understanding that with 24 hours' notice, we'd give it back if needed."
To maintain security, E&B subcontracted with Kentuckiana Off-Duty Police & Surveillance, Inc., of Bardstown, Kentucky, an MBE and WBE company, to make sure only authorized personnel entered through the construction gates.
The TSA required most project personnel-including laborers, operators, drivers, superintendents, and foremen-to go through an extensive process for security badges. That included a digital fingerprint checked by the FBI, a detailed background check, special training, and a test over airport policies and procedures. Anyone without a badge required an official escort.
Bigger Than Any Difficulty
To complete the work within the short timeframe, E&B supplemented their equipment inventory with rented excavators and bulldozers from Louisville-based Brandeis Machinery and other local dealers. L.L. Brown in Scottsburg, Indiana, supplied the 110-ton Link-Belt crane to set the heavy precast tunnel arches.
Sallee praised the teamwork that kept the job running smoothly. "It was a total team effort with the airport management, engineering team, suppliers, and contractors. Everybody realized that the overall project was bigger than any individual detail or difficulty. There was a lot of work to get done in a very short period, so we all focused on any problems that came up and resolved them quickly."
Most of the project is already complete; work on the RSA pavement and EMAS installation will continue as scheduled until November 1st.