When the highway meets the runway: conditions critical for success
Large aviation expansion programmes can involve integrating new and existing infrastructure. Aviation Director Derek Holden looks at some smart ways to deliver these types of projects not only safely and sustainably, but more innovatively and efficiently.
Major airport expansions and developments are always opportunities for innovation. And when space and time are critical factors, the pressure is on to produce successful results first time.
To match the ambitious changes at airports, ambitious responses are required. This is especially the case when space is limited, leading to the requirement to build new airport infrastructure over, through or around existing roads, railways, major utilities or other structures. Along with complex technical challenges, other requirements include maintaining a business-as-usual service, maximising safety, minimising disruption to the public and passengers, reducing the carbon footprint and, of course, delivering on time and to budget.
A guide to key tools and approaches
Based on our recent experience, here are some of the key tools and approaches used to deliver major aviation projects, where new and existing assets must work together.
Contracting
Constructing a runway over existing infrastructure, such as a highway, is inevitably challenging. The driving theme behind any construction contracting strategy to deliver these types of projects efficiently and safely should be clear and appropriate allocation of risk between all parties, and development of key details prior to award of any final contract for delivery.
The intelligent use of early contractor involvement provides the perfect vehicle to identify, or at least sufficiently detail and apportion, the key risks. Ultimately the owner/operator would need to be clear on the objectives driving their contracting strategy, balancing cost, schedule and risk certainty with other less tangible aspirations which determine what successful delivery looks like to them.
Design
Creating a virtual vision of the runway before starting construction makes it easier to the trained eye to spot any design anomalies. Technologies and applications such as 3D fly-through, immersive technology, driver simulations and 4D, 5D and 6D technology can enable the design and construction teams to gain a holistic view of the proposed project which is simply not possible in two-dimensional design. In addition, the use of BIM with its potential to drill down into the smallest detail, opens up a whole new world of better coordinating design and construction, and maintaining operations and maintenance. The BIM model can be the single source of truth for even the most complex project, and its usefulness is strengthened by including input from the existing infrastructure owner, adjoining property owners and businesses and first responders in the design review process.
Using the DB delivery approach will save time by enabling the contractor to perform some work in advance of a completely accepted design, and design costs can be reduced. It is, however, crucial that DB design reviewers and selection teams are open to new ideas: the Hartsfield Jackson Atlanta International Airport Firth Runway Project runway structure procurement resulted in a design concept foreign to what the airport and Georgia Department of Transportation anticipated. The concept was novel, but was accepted after much discussion and review against the criteria, saving over US$50 million from the project budget.
Early access to materials
Large-scale aviation projects often require importing significant amounts of fill, especially where ground levels need to be raised. When building a runway over an existing railway or highway, locating, accessing and buying the rights to large quantities of fill early on in the project lifecycle is crucial to avoiding project delays and being able to place material of the right specifications in the optimal locations, maximising overall re-usage. On the Atlanta project, the amount of imported fill was significant. Gaining early access to the fill and developing an innovative means to transport it helped to mitigate what would have been a traffic and logistical nightmare. The delivery speed of fill allowed us to collaborate with the contractor to develop and quantify an approved placement method and quality acceptance protocol to keep placement of the fill in sync with material delivery. At Fort Lauderdale, an apron pavement reconfiguration project was being delivered simultaneously to the main works contributing some of the required fill. Having access to abundant amounts of fill or finding, vetting and purchasing it can save millions in contractor billings.
Innovative construction methods
Speed of delivery and increasingly tough environmental standards, such as carbon emission targets, are driving the requirement for quicker and more sustainable constructing methods. To import the required fill at Atlanta, the team used an elevated conveyor belt which moves dirt at a rate of one cubic yard per second. The 26,000-foot-long (eight-kilometre-long) conveyor, removing truck trips on Georgia’s roadway system and eliminating well over 2,6000 tonnes of polluting emissions. The conveyor crossed over five active roadways, creating safer construction conditions than a conventional truck-based soil transport system.
Meticulous site logistics
The size and volume of equipment needed to deliver major aviation projects require continuous and systematic attention to site logistics. The many contractors, utility companies and stakeholders need to be coordinated at all times. As construction manager of the Atlanta project, where we helped build a runway over 10 lanes of interstate traffic, we developed and put in place a detailed logistics plan for the project’s five-year construction programme. The ‘living document’, which was updated on a regular basis defined limits of work by package, landside access, emergency response procedure, staging, safety and security access and coordination points.
CASE STUDY Fort Lauderdale–Hollywood International Airport Expansion Program, Florida, US
To minimise flight delays and accommodate larger commercial aircraft, Fort Lauderdale-Hollywood International Airport (FLL) needed to extend its South Runway, giving the airport two parallel commercial runways, helping keep flight delays to a minimum, reduce taxi time to and from the terminals and increase safety. But limited space for the expansion meant building a 60-foot-high (18-metre-high) man-made embankment and concrete bridge structures to allow the runway and adjacent taxiway to cross over US Highway 1 and the Florida East Coast Railroad line.
As programme manager, AECOM oversaw the elevation of the runway and taxiway structure to cross the highway and railroad, extended the runway, demolished reconfigured the existing concourse buildings and relocated facilities while maintaining business as usual and minimising disruption to the traveling public.
FLL fast facts:
- The South Runway has been extended from 5,276 to 8,000 foot (1.6 to 2.4 kilometres)
- The runway elevates 65-foot (20 metres) at its eastern end
- Using recycled pavement from the old runway eliminated 1,229 trucks hauling fill to site
- The project included restoring 29 acres of wetlands and relocating over 1,300 trees
- Fill was transported via a railroad, eliminating 26,736 dump truck trips
- Six structures support the runway
- Six structures support the taxiway
- 2,648 concrete pilings installed
- 8,000,000 cubic yards of fill used — enough to fill the Louisiana Super Dome more than 1.5 times.
CASE STUDY Hartsfield Jackson Atlanta International Airport Firth Runway Project, Georgia, US
Often compared to the Golden Gate Bridge in terms of complexity, the Hartsfield Jackson Atlanta International Airport (ATL) Fifth Runway Project included the design and construction Georgia’s first runway tunnel and the world’s longest runway bridge spanning 500 foot (152 metres) and up to 18 lanes of traffic across Atlanta’s Interstate 285 Highway loop (I-285), which encircles Georgia, connecting three major interstate highways.
AECOM provided construction management services on the project and multiple other large-scale projects under the Hartsfield-Jackson Development Programme. During the relocation of Sullivan Creek underneath the runway, we encountered differing site conditions. Identifying that the original project designer’s methodology would have delayed the placement of fill on site, we presented a second designer’s opinion to mitigate the delay and allow for schedule corrections. The project was delivered early due to rigorous schedule oversight of 12 contracts and US$200 million under budget.
The Hartsfield-Jackson Development Programme is a massive programme to improve infrastructure to enable and promote growth, improve efficiency and enhance customer experience at the airport. Completed airfield projects include the US$1.2 billion Runway 10-28, the US$92 million demolition and reconstruction of ATL’s Runway 8R and its parallel taxiway within 60 days, and multiple other airfield reconstruction and enhancement projects.
Under the Fifth Runway Project five-year contract specifically, AECOM led the joint venture design-build team in the successful implementation of four interwoven contracts. The end result was delivery on time and under budget with project winning the Airports Council International-North America Environmental Achievement Award in the Large Hub category.
ATL fast facts:
- Longest airport runway highway crossing in the US
- The runway’s two bridge structures span nearly 500-foot (152 metres) of interstate
- More than 18 million yards of engineered embankment placed in 22 months using a conveyor system for soil transport.
- When the 9,000-foot (2.7-kilometre) runway opened, ATL became one of four airports in the US where three commercial airplanes can land simultaneously.
- ATL is one of the busiest passenger airports in the world