Sustainable infrastructure initiatives take off

The Port Authority of New York and New Jersey (PANYNJ) oversees some of the largest and busiest transportation facilities in the country. The aviation network carries approximately 107 million passengers, ships 1.3 million tons of air cargo, and includes 1.3 million flights on an annual basis. The five-airport system covers about 11,000 acres and includes approximately 20 miles of runway, 50 miles of taxiway, and 70 acres of apron pavement. The port facilities include six container terminals covering more than 1,300 acres. The tunnel and bridge system includes four interstate bridges and two tunnels, which carry approximately a quarter billion vehicles each year. For instance, the George Washington Bridge carried more than 100 million vehicles in 2009 and almost 10 percent of these vehicles were trucks.

As these facilities age and the need for rehabilitation increases, it is critical that the designs developed consider facility disruption and life-cycle cost to minimize wherever possible the impact on the public both within the region and beyond. The agency continually strives to deliver engineering designs for infrastructure projects that reflect the latest industry standards and are cost effective and sustainable. As the industry moves toward greater adoption of sustainable civil engineering practices, the PANYNJ has implemented practices described in this article that minimize environmental impacts, including stormwater management, reuse of materials and onsite recycling, trenchless technologies, pavement management, and wetland mitigation.

Stormwater management
The PANYNJ has implemented numerous best practices in stormwater management at its facilities throughout the agency. These include extensive use of manufactured treatment devices, infiltration trenches, underground detention, and the use of pervious pavement. Each project is evaluated based on regulatory requirements, environmental impacts, and potential impacts on cost and schedule before the decision is made on which systems to utilize.

At Stewart International Airport (SWF) in Orange County, N.Y., a fast-track design and construction project was initiated in August 2007 to complete a new parking lot within a three-month window. To expedite the permit process, the parking lot was designed using a pervious asphalt pavement system resulting in 100 percent of all stormwater infiltrating onsite. The 3-acre parking lot was completed on schedule in November 2007.

A second SWF project involved a 6-acre expansion of the main terminal parking lot. This lot also used a pervious asphalt pavement system and had an extensive subsurface stormwater drainage collection system. This system consisted of infiltration trenches, a sub-base with large voids, extensive use of rain tanks with filter fabric, as well as an extensive sub-drain system. This system infiltrated 100 percent of all stormwater at the site with no connection to the existing storm drainage system. The irrigation system uses collected rainwater from a central cistern and is equipped with solar-powered irrigation pumps.

Warm-mix asphalt
The PANYNJ initiated the use of warm-mix asphalt on a recent parking lot and roadway rehabilitation project. The environmental benefits of warm-mix asphalt include less energy consumption and fewer emissions during production; fewer emissions during construction; less equipment required and, consequently, fewer emissions during pavement construction; and potential enhanced durability. Recent warm-mix contracts were a parking lot rehabilitation at Newark Liberty International Airport and rehabilitation of the main restricted vehicle service road at John F. Kennedy International Airport (JFK).

Trenchless technology
The PANYNJ has used trenchless technology since 1991 on various projects. Trenchless technology reduces the amount of material removed and displaced, which reduces the energy required to construct compared with open-cut methods. Additionally, this technology reduces disruption to the site, which minimizes traffic congestion and air pollution during construction. At JFK, microtunneling was used to install power, water, and sanitary sewer lines both in the central terminal area and on the airfield. At Newark Liberty International Airport (EWR), a major microtunnelling project involved installing a new 20-inch water main to provide a redundant supply to the airport. This project was located under a major thoroughfare in New Jersey, Route 1 & 9, and crossed under 10 lanes of traffic.

At SWF, the sanitary sewer system had a significant infiltration problem, which was overloading the local town treatment facility. The PANYNJ Engineering Department evaluated the system and looked at various repair and replacement options. Two trenchless technologies were chosen as the final design solution. Pipe bursting was used to replace the main trunk lines and a cured-in-place pipe (CIPP) was used for a 700-foot section that was adjacent to building foundations. The use of these technologies minimized the need for excavation and had the added benefit of minimizing disruption to the airport. Approximately 4,000 feet of 6- and 8-inch pipe were replaced or lined using these technologies.

Wetland mitigation
The PANYNJ initiated a major project to improve rail access to the Port Newark and the Elizabeth Port Authority Marine Terminal. This included providing support track to accommodate 2-mile-long trains and to integrate the rail traffic to and from the PANYNJ’s three ExpressRail facilities. As part of the environmental permit required for the project, a stormwater management system needed to be installed and a wetland mitigation area needed to be developed. An underground detention system was designed using five 48-inch concrete pipes, 250 feet in length. The water then went to a stormwater filtration device before discharging into the wetlands. A wetland mitigation area was also constructed in an adjacent area to comply with all permit requirements. This mitigation area included planting areas for Baccharis Halimifolia and Spartina Alerniflora.

Onsite material recycling
In preparation for the arrival of the A380 airplane, the centerline of one of the main taxiways at JFK needed to be shifted 16 feet for a total length of approximately 4 miles. A detailed study was conducted to evaluate the potential reuse of existing asphalt, lime cement fly ash pavements, and sandy subgrade soil. It was determined that the existing pavements could be reused onsite as a base course for the new pavement. The pavement was removed, crushed, treated with portland cement, and remixed onsite, and a rigorous testing program was followed to ensure all specification requirements were met. This eliminated the need for approximately 25,000 cubic yards of virgin material, and saved approximately $2 million in construction costs as well as significantly reduced truck traffic for aggregate delivery.

Construction debris recycling
Since January 2009, all PANYNJ contracts require the contractor to submit a Construction Debris Recycling Plan. This plan requires the contractor to provide documentation that 75 percent (by weight) of all steel, asphalt, concrete, and clean soil is recycled on a project-by-project basis. This goal has been met since the contract specification was introduced.

Pavement management
The PANYNJ has a comprehensive pavement management system that is used to manage rehabilitation and replacement of all PANYNJ pavements. Pavements are inspected on a regular cycle and pavement condition indices are developed. This information is combined with repair history and original construction documents to develop the type and recommended year for rehabilitation. This system ensures that pavements are rehabilitated at the correct time and funds are properly expended. Preventive maintenance such as sealcoats and thin overlays are also recommended where appropriate to extend pavement life and enhance pavement life cycle. Utility systems are also evaluated and replaced where appropriate to eliminate having to disrupt the area prior to the next pavement rehabilitation.

At the George Washington Bridge, all truck traffic has been required to use the upper level roadway since Sept. 11, 2001. The pavement consists of a 2-inch asphalt wearing course over a steel orthotropic deck. This additional truck traffic resulted in a reduced pavement life and required additional facility maintenance resulting in additional facility disruption. A study was undertaken to evaluate the potential for a high-performance, low-maintenance, more durable pavement system. After extensive testing, an asphalt mix was developed that included an additive — Rosphalt 50, as manufactured by Pittsburgh-based Chase Specialty Coatings. This mix was included in a major rehabilitation of the eastbound upper level in 2008. Since that time, it has also been included on the New Jersey approach to the Lincoln Tunnel and is currently being placed on the westbound lower level of the George Washington Bridge. This pavement has low air voids and also inhibits moisture from reaching the steel deck.

Sustainable infrastructure guidelines
Although there were many sustainable infrastructure initiatives under way throughout the agency, there was no central tracking mechanism to document their use. In addition, there was no centralized standard or reference document of these strategies for staff and consultants to use. To ensure that all potential sustainable infrastructure initiatives were evaluated on a project-by-project basis and to document these initiatives, the PANYNJ initiated an effort in 2009 to establish sustainable infrastructure guidelines for the agency. An interdepartmental team was established to spearhead this effort. Existing infrastructure guidelines in use by other agencies were evaluated for potential use by the PANYNJ. Because of the variety of facility types and the nature of the contracts at the PANYNJ, it was determined that we would need to develop a guideline specific for the agency. It was also determined that the guidelines needed to be flexible to reflect the variation in the type of work that is done from basic rehabilitation to major capital construction.