Hartsfield Runway Spans Interstate

Hartsfield-Jackson Atlanta International Airport's new 9,000-ft.-long 1/28 runway is part of the airport's $5.4 billion expansion plan.

by Victoria L. Tanner

Scarlett O'Hara and Rhett Butler have long reigned as Atlanta's brashest couple, but once Kathryn Masters and David Casey finish the ambitious construction project they're leading at Hartsfield-Jackson Atlanta International Airport, O'Hara's and Butler's title may well be gone with the wind.

Masters and Casey are involved in building a critical component of Hartsfield's new 9,000-ft-long 10/28 runway, the centerpiece of a $5.4-billion airport expansion. Their massive $159.5-million bridge structure will permit the runway to cross over Interstate 285, allowing planes to take off and land literally atop the busy road.

The bridge configuration is believed to be unique. It will span 10 lanes of traffic but allow for eventual expansion of the road up to 18 lanes. The bridge is so vast that the support structure will create a tunnel, although none of it is underground. The structure will be the first roadway tunnel in Georgia.

"When I first took over the project and they told me it was design-build, I thought it was going to be a disaster," said Masters, senior project manager for International Aviation Consultants, the joint venture providing program management services to the City of Atlanta and its Department of Aviation for the five-year expansion project. "The city has never done a design-build like this," Masters said. The project's intense schedule made design-build a logical choice, although she acknowledges that city officials have "found it very difficult to give up control" under the design-build paradigm. IAC is comprised of Parsons Aviation, Rosser International, H.J. Russell, Turner Associates and URS Corp.

Masters knew that the project's proximity to state roadways also would require a close working relationship with the Georgia Department of Transportation, another agency with limited knowledge of design-build project delivery. "I've always thought this job was like having two novice owners," said Masters. She worried that GDOT's internal structure was not well suited to the demands of the job's fast-track schedule, fears that so far have not materialized. Since the job's kickoff in early 2003, the team and the project have come together quickly. "It's gone very well so far," said Masters. "We're on schedule and on budget."

For the design-build team, juggling tight schedules and budgets is just part of the process. But coping with the unique design and engineering demands of the project raises the stakes considerably. The structure incorporates a main runway bridge that measures 1200 ft long and 486 ft wide, and a 450-ft-long, 450-ft-wide taxiway bridge. Casey, program manager for Archer Western Contractors Ltd., Atlanta, leads the design-build team. The Atlanta office of Parsons Brinckerhoff Quade and Douglas Inc. is the team's lead design engineer, while Heath & Lineback Engineers, Marietta, Ga., is handling the project's structural design.

advertisement

The design-build team did extensive preliminary engineering work as part of a 15-month pre-bid process in which the city conducted workshops for potential bidders to learn about the job and exchange ideas and information as the request for proposals was being developed. "I think a lot of good things came out of that process," said Casey. "The city looked for everyone to bring out the things that were going to cause significant issues later on." Masters said the process allowed bidders to "ask questions without giving away the farm."

The pre-bid process also gave the design-build team the opportunity to study the minutiae of the city's preliminary plans. "The hardest part in the pre-bid process was determining what would and would not be accepted as being responsive to the RFP," said Gary Lineback, senior structural engineer at Heath & Lineback Engineers.

The RFP featured a 35 percent design concept developed under a separate city contract. The preliminary designs were used primarily to familiarize various agency groups with the overall concept for the bridge, thus helping to pave the way for the design-build process as it moved forward. Specifics of the drawings were not expressly written into the RFP "because we felt there was no need to be so dictatorial," Masters said. However, the city did have "eight non-negotiable items," including essential criteria like the number of lanes of traffic to be accommodated. Beyond that, bidders were given a wide berth in preparing their proposals. "The RFP allowed for quite a bit of innovation," said Archer Western project manager A. Steven Hausler Jr. "And we went for it."

Load Limit

Lineback shouldered considerable technical burden. The load standard for the entire runway was set at 1.4 million lb. The bridge was required to handle loads created by aircraft, such as the Boeing 747 (at 1.04 million lb) and the Airbus A380 (at 1.33 million lb). Variations in aircraft wheel configuration also had to be factored into the design equation, as well as the impact and influence of loads and force created by shear.

Given the set of variables, Lineback realized that his design would require a unique solution. "I don't know of any place in the world to have a project like this that is as big or as high," he said. Lineback's design features 764 "T-shaped" precast concrete beams with a total length of 90,000 ft. The beams are 81 in. tall and vary in length from 94 to 133 ft for both the runway and taxiway bridges. The combined bridge decks total 725,000 sq ft and will contain approximately 37,000 cu yd of concrete. The bridge structure consists of 430,000 sq ft of cast-in-place and precast walls. The runway's interior substructure features solid concrete walls measuring 3.25 ft in thickness and varying in height from 35 to 60 ft.

Given the nature of the tunnel structure, the Archer Western team knew that the life-safety systems required for the project would be a major cost component. Turning to the design expertise of Parsons Brinckerhoff, the team undertook a comprehensive ventilation study to determine the best methods for complying with code. "Going into the bid, we were looking at ways we could make the biggest impact with innovative design," said John Durand, PB project manager. "We did extensive computer analysis, with real-time models of the ventilation and we modeled the evacuation of people in there as well."

Based on the study's findings, the team developed its proposal around a dramatic decision to eliminate a conceptual false ceiling that was in the plans. "It was in the RFP with a note that it was there for ventilation purposes only and in our ventilation analysis we decided it wasn't needed," Casey explains. The Archer Western team's proposal provided the city with documentation supporting its argument. "We saw eliminating the ceiling as a very good opportunity to save money so we attacked that pretty heavily. We were able to reduce the number of fans that were placed in the tunnel to forcibly evacuate smoke by utilizing that ceiling space," said Durand. The resulting design features a life-safety system that includes 10 jet fans, 12 egress doors, emergency power generation, 4,968 light fixtures, 120 carbon monoxide detection monitors, a fire protection system and video monitoring. Casey acknowledges that the extensive pre-bid design work came with a high price tag. "The risk is so much higher, with no chance to recoup those costs," he said.

The city prequalified five firms to participate in the two-part, technical and price, bid process. Once it reviewed the technical proposals and deemed them responsive to the RFP, bids were opened and the award was made to the low bidder. Only two teams submitted final bids and the award created considerable controversy.

Landmark

The Archer Western bid was approximately $20 million below a bid submitted by 5R Constructors LLC, Atlanta, a partnership of S.W. Matthews, APAC Georgia and Michael Thrasher Trucking. 5R Constructors already is working at the airport with a $350-million earth-moving contract that involves transporting 27 million cu yd of earth to the runway site. After losing the bid, 5R Constructors filed suit in federal court, seeking a temporary restraining order to stop work. It claimed that the winning bid was not responsive to the RFP. U.S. District Court Judge Owen Forrester denied the request and cleared the way for the city to ink its deal with Archer Western in early December 2002. No further legal action is planned, said George Wenick, an attorney with the Atlanta law firm of Smith, Currie & Hancock LLP, which represented 5R Constructors.

The Archer Western team credits its advance work in the engineering design for giving them the winning edge. "I would say our team out-engineered the other team in many ways," said Durand. "One of them was ventilation, one of them was the innovative superstructure design, and then there were a lot of smaller items." Besides besting 5R's numbers, the winning bid was $80 million below the city's initial estimate for the project.

But perhaps more importantly, the extensive advance design work allowed the Archer Western team to hit the ground running once the contract was awarded. Durand estimates that under a traditional design-bid-build approach, the tunnel's life-safety systems alone would have required approximately two years of design work. The design-build approach brought the project to 95 percent design completion in approximately seven months.

With design nearly complete, Archer Western's construction team, which is self-performing approximately 55 percent of the construction work, now bears the burden of maintaining the project's accelerated pace. Completion is scheduled for February 2006, with commissioning set for May 2006. Casey said his team is up to the challenge. "This is going to be a landmark project in this city," he said. "Everybody's going to see it and we all want to make sure that everyone knows that it was a quality project that all of us worked together to achieve."

With the busy jobsite humming behind them and 10 lanes of traffic rushing past, Masters and Casey survey the work with an unmistakably proprietary air. They know it just might be one of the highlights of their relatively young careers and they're clearly proud of what they are achieving. "After this job, there's not much more you could hope for," said Masters.

Reprinted from Design-Build, copyright the McGraw-Hill Companies Inc., December 2003. All rights reserved.

Key Players:

Owner: City of Atlanta's Department of Aviation
Program Manager: International Aviation Consultants, a joint venture of Parsons Aviation, Rosser International, H.J. Russell, Turner Associates and URS Corp.
Contractor: Archer-Western Contractors, Atlanta
Design Engineer: Parsons Brinckerhoff Quade and Douglas, Atlanta
Structural Engineer: Heath & Lineback Engineers, Marietta, Ga.