GAI provided preliminary design and design management services during construction to PennDOT District 4-0 for the design-build of a retaining wall along the eastern side of SR 0191 between the roadway and the Delaware River in Wayne County. A slope of approximately 1.25:1 along the existing, two-lane roadway had caused substantial differential cracking in the pavement, creating a potentially hazardous driving situation for motorists.

Geotechnical investigation—including test borings and installation and monitoring of inclinometers to obtain deep-seated slope movement data—determined that the installation of a retaining wall was the optimal solution to correct the slope stability issue. The District required maintenance of one traffic lane during construction due to extremely long detour length; this resulted in the use of a combination of reinforced soil slopes (RSS) and soil nail wall. The project also involved reconstruction of a 430-ft segment of SR 0191 to repair damage to the roadway. The lane adjacent to the new retaining wall was a full depth reconstruction, while the interior lane was milled and overlaid. New guide rail was also installed throughout the project limits.

GAI’s design services included survey, right-of-way investigations, geotechnical investigations, utility investigations, preliminary plans, preliminary retaining wall designs, and plans, specifications, and estimates (PS&E) package. During the construction phase, GAI provided construction consultation, shop drawing reviews, final plans review, and structure design and plan reviews.