Schnabel is a subconsultant on a National Park Service multi-disciplinary Architect Engineer design services IDIQ contract for projects throughout the Northeast and National Capital Regions. Completed tasks help to restore, maintain, or renovate historical and recreational sites through services that include pavement and subsurface investigations, soil sampling and laboratory testing, and geotechnical engineering.

Fredericksburg and Spotsylvania National Military Park in Spotsylvania County, Virginia – We performed a visual assessment of battlefield pavement conditions and targeted subsurface explorations to document the existing roadway conditions. We provided recommendations for pavement preservation treatments or rehabilitation based on the roadway condition. Our evaluations were conducted in accordance with the 1993 AASHTO Pavement Design Guide and Virginia Department of Transportation design requirements.

Delaware Water Gap Recreation Area, Route 209 from East Stroudsburg to Dingmans Ferry, Pennsylvania – We evaluated 7 miles of roadway by performing a visual condition assessment and a subsurface exploration to document the existing pavement conditions. Recommendations were provided for mill and overlay in areas exhibiting low to medium distress. Complete asphalt replacement was recommended for a section where we observed medium to high severity distress.

Flight 93 Memorial in Stoystown, Pennsylvania – We evaluated the roadways by performing a visual pavement condition assessment and a targeted subsurface exploration to document the existing pavement condition. We recommended resurfacing the majority of the park roadways and suggested pavement preservation treatments. For specific sections of the memorial roadways that exhibited slippage cracking, we provided recommendations for performing a deep mill and overlay to correct the poorly bonded pavement surface layer.

Gateway National Recreation Area in Sandy Hook, New Jersey – We provided geotechnical engineering services to relocate maintenance and storage facilities damaged by Hurricane Sandy. The project scope included a subsurface investigation, laboratory testing, classifying soil and determining engineering properties, and preparing a geotechnical report for each site utilizing test borings, infiltration tests, and bulk samples for testing. Our recommendations included the evaluation of allowable bearing pressures for shallow foundations, slabs on grade, pavement designs, and construction considerations. We were responsible for oversight and preparation of calculations for foundations and pavement designs and also provided construction phase services for the foundations, pavement, and earthwork. On a separate project, we provided horticultural soil sampling services in the woodlands. After our field investigation, sampling, and subsurface investigations, we prepared a findings report summarizing the subsurface and surface conditions encountered during the field investigations.

Charles Young Buffalo Soldiers National Monument in Xenia, Ohio – We provided geotechnical engineering design services for a renovation and rehabilitation project at this monument, which commemorates the life of an escaped slave who rose to become a respected military officer. The scope included a geotechnical investigation with borings and test pits to provide recommendations for the installation of a proposed elevator pit, underpinning of existing perimeter foundations in areas of full-height basement and shallow foundations with crawlspaces, and design support of a perimeter drainage system. The monument’s current footprint includes the existing structure and two additions. The structure is supported on several types of shallow foundations, including a shallow stone wall and concrete footings.

National Mall in Washington, DC – We’re serving as the geotechnical engineer on a team to rehabilitate gravel walkways in several locations throughout the park as well as upgrade buried electrical and telecommunication systems. We performed a desk study to review the existing geotechnical data at the National Mall and evaluated the potential geotechnical risks to the project. We reviewed the existing National Mall Plans, WMATA tunnel plans, existing and abandoned utility plans, stormwater management plans, and existing geotechnical reports and provided a summary of our findings to be incorporated in the pre-design phase documents.

Little Round Top visitor center in Gettysburg National Military Park, Pennsylvania – We performed a subsurface investigation, laboratory testing, and geotechnical engineering analyses. The proposed upgrades will enhance pedestrian circulation, eliminate numerous safety concerns, and preserve and protect the existing site features. The Little Round Top visitor parking area and Sykes Avenue will be widened to increase vehicle and pedestrian access by incorporating embankment fill and a new retaining wall. The two-phase investigation included test borings at the retaining wall and a visual site reconnaissance to evaluate the stability of existing masonry walls, monuments, and rubble-masonry walls. The project design phase is ongoing, and we’re assisting in stormwater management design and pavement design of surrounding roadways.

Saratoga National Historical Park visitor center in New York – The visitor center required an upgrade to their in-ground septic system due to the system’s age as well as increased visitor traffic and events. We designed and implemented a comprehensive boring, percolation testing, and test pit plan to gather infiltration data over a proposed new septic field, in accordance with NYDEC 2014 Standards for Soil Evaluation Part B and local health department guidelines. The plan included 12 borings and 4 test pits. Our engineers logged the borings and test pit soils and performed percolation testing on all of the borings. We included our findings in a final report along with recommendations for the final configuration and placement of the leach field.

Photo: James Steakley, Wikimedia Commons