FEATURE ARTICLE, FEBRUARY 2005

Designing on Brownfields
Creative architecture is key to a successful brownfield development.
Philip Daly

As open green land becomes harder and harder to come by in many parts of the Northeast, developers are taking another look at brownfields. Many of these sites are located in highly desirable areas, and despite the challenges and risks of taking them on, these sites can be lucrative investments.

An example of these challenges can be seen in the recent development of a landfill site in eastern Massachusetts. The 33-acre former town dump, located just off one of the area’s busiest highways, had been an eyesore, major liability and tax drain for the town since it closed some 20 years ago.

Vendors were thrilled with the location and quality of the development, the developer realized a good return on its investment, and the town is receiving much-needed new tax revenue. But make no mistake: Getting to a win-win situation on a brownfield site is a challenge.

There are no set solutions for brownfield developments. Each development is uniquely driven by the nature of the environment, market and location. Frequently, former landfills are turned into developments like parks, playing fields or golf courses.

In the case of the eastern Massachusetts development, the location and high visibility justified a higher use for the land. Because the site was a former landfill, most of the buildings had to be supported on piles. Pile foundations are expensive and introduce an element of risk, especially when dealing with former landfills. For example, the contractor may be driving a cluster of piles, get three in, and the fourth might hit an old engine block and break, making it necessary to redesign the whole cluster immediately. The developer in this case minimized some of the risk through extensive test drilling, pre-excavation and pre-augering. But you can never eliminate all of the risk — or the cost — associated with pile driving on a landfill.

Methane gas is a major issue that developers face when developing on landfills. Sometimes the gas can be collected and turned into a useful energy source. In the Massachusetts development, studies indicated that there was insufficient gas for generating electricity. Nevertheless, a gas collection system had to be installed under the entire site and building. The gas is drawn through a network of pipes to a flare station where the gas is burned off. The gas collection system in turn created a need to install a separate, sub-surface drainage system.

On top of these two systems, the developer had to install an impermeable cap membrane that needed to be sealed as tight as a roof covering. Any penetrations through the cap layer had to be avoided or carefully detailed to maintain the seal. These penetrations obviously included the foundation piles, but also included a myriad of other items such as fence posts, sign posts, light poles and pipe bollards, to name a few. The cap layer also had to be contoured to provide corridors for the site utilities and to drain to the site perimeter without low spots. Only environmentally clean and certified fill material could be installed above the cap layer. The surface then had to be graded to meet all the surface drainage and building access requirements of a normal building project.

While the project civil engineers and geotechnical consultants were responsible for creating solutions to the problems already mentioned, designing the actual buildings and amenities that can be built on such a site posed a whole different set of challenges for the architectural team. Because the site is a former landfill, there is a high degree of anticipated settlement — as much as 24 inches in some areas. Since the building is sitting on piles, it is not going anywhere. But sidewalks leading into the buildings could settle, creating entry problems. In some cases sidewalks were installed on piles with an additional hinged slab to transition to the paved areas. In other areas, the sidewalks were cantilevered off the building.

Utility connections coming into the building are also rigid at the building line, but could settle where they run in the site material. The high degree of anticipated settlement required that each utility line had to be individually engineered with expanding flex joints. Utility lines beneath the building are suspended from the structural floor slab. Each hanger penetrating the cap membrane had to be carefully sealed and tested before the slab could be poured.

The nature of the site required that even the most mundane construction details be re-examined. One small example was the parking lot lighting poles. Placing these on pile supports was not economically feasible but the size of footing required to keep the poles from tipping over would have caused the footings to sink under their own weight. We designed some of the poles with hollow footings that would settle at the same rate as the surrounding site.

Another problem was handling the surface drainage from the parking areas. Due to the cap membrane there was little or no permeable area. Typically, a site like this will include a large retention pond to hold excess water from paved parking areas. Retention ponds are usually open depressions. Instead, one of the retention areas was located under the parking lot while another is located under one of the buildings.

Another challenge of brownfield development is the lack of precedent. Developing brownfield sites is still an evolving science and since the problems are unique to each site, there are few off-the-shelf solutions. But that is sure to change as more developers are tempted to remediate and develop brownfield sites.

Building on environmentally compromised land is not easy or cheap, but as this project has shown, it can be done to everybody’s benefit. q

Philip Daly is an associate and architectural discipline leader at Carter & Burgess in Boston. As architectural discipline leader, Daly is responsible for providing technical leadership and the development of the architectural department.


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