Pennsylvania Turnpike Southern Beltway, Southwestern Pennsylvania
Overview: Since 2013, GeoStructures has teamed with the Mechanicsburg, Pennsylvania office of Stantec to provide geotechnical design services for a new 3-mile section of the $700-million, 13-mile tollway of the Pennsylvania Turnpike Southern Beltway. Construction for Section 55B of the Southern Beltway began in January of 2017.
Major components of Section 55B included a 5-span bridge (170-ft high), cuts and fills (160-ft high), an MSE wall, a 1.5:1 steepened rock embankment, 2 culverts, 1 mile of side road improvements & relocations, and 15 stormwater basins. The field exploration portion of this project involved 158 test borings (maximum depth of 200 ft), inclinometers, stormwater infiltration tests, and pavement cores with DCP testing along existing side roads. The following research and design measures were also implemented during the project:
- Research of historical coal & strip mine records
- Interpretation of coal mine boring data to develop composite foundation for the 5-span bridge
- Research of ancient landslides and detailed risk assessment of 14 closed-form landslide features mapped by USGS
- Use of LIDAR data and exploration data from test borings, inclinometers, and residual direct shear testing to identify 5 high-risk landslides containing colluvial soils, active shear zones with friction angles as low as 10°, and artesian groundwater conditions
- Design of a drainage blanket and rock buttress mitigation plan to stabilize landslides as large as 75,000 CY below the main line, as well as along several high-risk basin side cuts
GeoStructures is now approved as a PennDOT Prequalified Geotechnical Drilling Contractor. ...
GeoStructures is the proud recipient of the Delaware Valley Geo-Institute 2021 Project of the...
GeoStructures is the proud recipient of the American Society of Civil Engineers 2019 Project of...
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