Specifications include, but are not limited to: The purpose of this Geotechnical Design Report is to present subsurface information and make geotechnical recommendations for the replacement of an existing large culvert (#47113) on Route 27 in New Sharon, Maine. A subsurface investigation has been completed at the site to evaluate subsurface conditions and to develop geotechnical design and construction recommendations for the replacement structure. This report presents the subsurface information obtained during the subsurface investigation and soil laboratory testing programs and provides design and construction recommendations and geotechnical design parameters for the culvert replacement. The existing structure consists of an approximately 6-foot span by 7-foot rise by 30-foot long concrete box culvert. The culvert is in poor condition, with deteriorating concrete, exposed rebar, and failing wingwalls. Route 27 is a Highway Corridor Priority 2 road. The proposed replacement structure will be an 18-foot span by 10-foot rise by 148-foot-long precast concrete box culvert on a skew of approximately 42 degrees to the roadway centerline. To facilitate fish passage, Habitat Connectivity Design elements will be used inside the proposed precast concrete box culvert as shown on the Culvert Streambed Details Sheet in the Plans. The invert of the proposed culvert is approximately 12.2 feet below the existing road grade and 16.2 feet below the proposed road grade at the roadway centerline. The roadway embankment slopes at the proposed culvert inlet and outlet shall be no steeper than 2H:1V to protect against erosion.
