The geotechnical challenges of designing structures at former landfill sites were highlighted at Geo-Chicago 2016 by two leading geotechnical engineers from PBS. Ryan White, PE, GE, and Arlan H. Rippe, PE, GE, D.GE were attendees and presenters at the annual conference focused on the latest advances in characterization, modeling, design, construction, and field performance in the rapidly expanding geotechnical fields of sustainability, energy, and the geo-environment.
The two senior engineers presented their work on the Astoria Athletic Field Project, a 12.5 acre former landfill developed for use as a recreational field complex for the local community. Development was planned through a partnership between Columbia Memorial Hospital, Astoria School District, the City of Astoria, and the local transfer station.
PBS provided geotechnical engineering services to support the design of structural foundations. “The biggest geotechnical hurdle was characterizing the unknown content of the landfill – the same area on which the structures would be founded,” stated White. “A number of design challenges were addressed – settlement of the landfill debris, foundation support of the grandstands, and developing economical alternatives for foundation support of the elevated field lights and scoreboard.”
The presentation outlined how PBS’ engineers responded to these challenges with a combination of surcharging, deep foundations, soil improvement, and special foundations designed using both engineering analyses and existing data.
“Based on our research and analyses, we found that structures on and around the landfill could be safe without being overly conservative, and could also be economical without being unsafe. In this case, it was possible to take an area of formerly unusable land and create a functional space to the benefit of the entire community.”