PTC MP 214-220 Total Reconstruction

Pennsylvania Turnpike Commission | Cumberland County, PA

The reconstruction of the Pennsylvania Turnpike Mainline from Milepost 214 to 227 in Cumberland County included replacement of the Mainline and overhead structures and the expansion of the roadway to six lanes. The project was divided into multiple sections that consisted of five to seven mile long segments with Early Action contracts for the overhead structures. Thirteen mainline structures and thirteen overhead structures were replaced during the project.

AEG provided geotechnical, survey, and Right-of-Way support during Preliminary and Final Design for the entire roadway alignment and all the proposed replacement structures. Due to Right-of-Way and environmental constraints, multiple sound barriers and retaining walls were also proposed and designed throughout the alignment.

The geology of nearly the entire project consisted of limestone bedrock formations. The calcareous bedrock of the region coincided with karst features including pinnacled bedrock surfaces, sinkholes, caves and voids, and other solution features. These surface and subsurface features required evaluation of remedial treatments such as over-excavation and replacement, pressure and compaction grouting, and micropile foundation designs.

Critical aspects of this project included the presence of karst conditions beneath at least three proposed bridge structures. A 30-foot-deep void was encountered directly beneath a proposed bridge abutment. AEG provided recommendations to remediate the karst conditions for foundation designs to minimize the risk of potential subsidence throughout the design life of the structures.

AEG provided on-site inspection of compaction grouting operations along with additional construction-phase consultation.

AEG managed several subsurface investigations, including the boring, sampling, and testing program for the roadway and structures. AEG prepared reconnaissance reports and boring layouts for the roadway alignment and proposed structures along with Geotechnical Engineering Reports and Structure Foundation Geotechnical Reports for proposed bridges, culverts, sound barriers, retaining walls and sign structures. AEG was also involved with the Infiltration Testing program and geophysical studies related to stormwater management.