The typical lifespan for a runway at a major U.S. airport is less than 20 years. But Hartsfield-Jackson Atlanta International Airport’s Runway 8R-26L
The typical lifespan for a runway at a major U.S. airport is less than 20 years. But Hartsfield-Jackson Atlanta International Airport’s Runway 8R-26L was recently removed and repoured after 37 years of supporting airport operations. Originally constructed in 40 days, the 10,000-ft.-long, 150-ft.-wide stretch defied engineers’ predictions and withstood decades of being a part of one of the world’s busiest international airports.
Earlier this year, the runway was identified in pavement evaluation as being the most distressed on the airfield. As a result, a three-phase, $90 million plan of action was organized that involved removing more than three miles of concrete, replacing underdrains and base material, and repaving the entire length of the runway ranging in thickness from 20 to 25 inches. In addition, the City of Atlanta Department of Aviation took the opportunity to add a new 4,500-ft. taxiway to the five-runway operation, eliminating the need for aircraft to cross over active runways to get to and from 8R. The entire project required about 150,000 yd. of concrete.
The added challenge for this project was the narrow 60-day timeline to get 8R open for full-scale operations. For each day over the deadline, lead contractor The Kiewit Company of Omaha faced penalties of as much as $225,000/day, so it’s no surprise the operation ran 24/7 until paving was complete.
Still the 60-day timeline is somewhat misleading, according to DOA Senior Project Manager Quintin Watkins. The first phase of the job actually took place in the 90 days leading up to the runway closure, he explains. We had to set up our batch plants; build the two-mile-long, 40-ft.-wide haul road from the plant to the runway; and, install a security fence so that when the runway was closed, the job site was contained from the rest of the airport. Extra security guards were placed at the crossing point of active taxiways.
We also took time to make small repairs and slab replacements of runways and taxiways that weren’t part of the main work.
Watkins estimates that during this phase 14, 25- _ 25-ft., 16-in.-thick replacement slabs were poured by George L. Throop Co. of California. We made these repairs overnight, replacing one slab per night during a 10-hour runway closure window, adds Watkins. For the first time in our history, we actually managed to do two in one night.
The defective slabs were saw cut by Kiewit the night before placement, dowel bars were installed, and a mobile mixer was brought on site to pour an accelerated-set mix that hardened in two hours.
The closing of the 8R runway on September 8 (the day after Labor Day) marked the beginning of Phase 2. Crews worked 24/7 to close down the main runway, as well as an existing 3,000-ft. taxiway, with concrete placement reaching about 5,000 yd. per day. Two crossing locations along 8R were required to remain open at all times to allow vehicle and plane traffic. When it came time to replace the crossings, they could only be shut down for a maximum of eight days.
According to Watkins, an average of 60 loads of low-alkali cement from Cemex’s Clinchfield, Ga., facility arrived on site every day, with 20 to 25 loads of fly ash coming from SEFA in Cumberland City, Tenn. Watkins explains that the mixes were 25 percent fly ash to control potential alkali-silica reactivity. As an added measure, engineers specified a lithium nitrate admixture. The aggregate in this region has been reactive in the past, he says. We did some testing beforehand, and after 14 days with this mixture we got no reaction. But after two years, who knows what will happen; the test doesn’t tell you that.
Kiewit was responsible for processing the runway’s subgrade, installing drainage, replacing electrical for runway and taxiway lights, laying a 3-in. layer of asphalt bond-breaker and slipform paving the runway surface. To keep things on schedule, the contractor used a double- and single-drum paving plant for high volume output. Three Terex Roadbuilding MTP4004B transfer/placers conveyed mixes to three slipform pavers.
Because of the around-the-clock schedule and the high demand for cement, the contractor realized that Cemex could not dedicate enough material to keep up with estimated daily requirements. As a result, the company investigated several cement storage alternatives for stockpiling material before work began. Ultimately the contractor purchased 14 new Terex M4700 silos for the job. Thirteen were dedicated to the double-drum paving plant, while the 14th was added to the company’s four existing silos for the single-drum plant. The silos offered a combined 16,800-bbl. capacity in a relatively small (105-sq.-ft. per silo) footprint.
Three Cyclonaire HC-150 conveyors (one for fly ash, two for cement) were used to vacuum load and transfer material from the silos to the Erie Strayer Co. 1,700 yd./hour batch plant. Air for the conveyors was supplied via two 2,000-scfm blowers. The configuration allowed one conveyor to draw material from any of two sets of five group cement silos and any of four fly ash silos. Powder needed to be conveyed at nearly 130 tons per hour during peak demand times.
Cement and fly ash was hauled by South Carolina fleet operator StarTrans Inc. About 2,300 loads (or 60,000 tons) of powder were required for the project, along with 961 loads of fly ash (or 25,000 tons). Each truck would back up to one of three designated unloading areas and hook up to the Cyclonaire turbo inductor to fill the silos. Discharge time was typically 20 minutes.
By mid-October, the 8R runway was completed, with joint sealing work done by T.L. Smith. Phase 3 of the operation was building the new taxiway, with a slightly less stringent deadline given to the work since reopening 8R was not dependent on its completion. Still, the job took only 15 days and required 2,000 to 3,000 yds. per day, with all work completed on November 6.
To understand the impact of closing a single runway at one of the world’s busiest airports for 60 days, Hartsfield-Jackson Atlanta International Airport and its top three airlines Û Delta, AirTran and Atlantic Southeast Û fell to the bottom of the industry’s on-time performance in September when 8R was shut down. The airport was 31st out of 31 airports in on-time performance for the month, according to a report in The Atlanta Journal-Constitution, with slightly less than 61 percent of flights arriving within 15 minutes of schedule.
For a time after its reopening, runway 8R was limited for daytime use only while lighting issues were addressed.