About this Project

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The US 11/15 Rock Slope Safety Improvement Project was divided into two sections approximately seven miles apart. The southernmost section, the Marysville Section, consisted of four primary rock cuts and was located north of the US 11/15 Interstate 81 interchange in East Pennsboro Township. The northern section, the Duncannon Section, consisted of one rock cut and was located in Penn Township, and was located approximately 0.8 miles south of the Borough of Duncannon. The project aimed to increase motorists’ safety by implementing a multi-faceted approach to reduce the risk of future falling rocks.

AEG provided preliminary engineering, final design, and construction consultation for the rock slope protection systems installed at each location. AEG was responsible for investigating the existing condition of the cut slopes, providing a comprehensive analysis of rockfall hazards, developing and recommending slope protection measures, and completing the preliminary and final design for the recommended actions.

Our analysis included the following:

• Performing detailed geologic mapping of the slopes
• Analyzing existing low altitude black and white and infrared aerial photography
• Colorado Rockfall Simulation Program (CRSP) modeling
• RockPack III computer-based analysis of the rock slopes
• Identification of potential failure mechanisms
• Producing digital photographs
• Determining rock shear and compressive strength

Recognizing the unique traffic impacts involved in each project area, traffic management was critical. Road widening and road closure options were evaluated. The project team coordinated with representatives of all state, county, and municipal emergency management services organizations that were affected, particularly during the Marysville Section detour. AEG provided expedited reviews of construction submittals and fast field responses to construction matters. The effort put forth by the design team assisted the Contractor in opening the roadway nearly one month ahead of schedule.