In general, guide rails shall be corrugated-beam
or cable-type construction. Box beam guide rails may be required and
approved for specific cases. All materials and installation procedures
shall comply with the standards of the New York State Department of
Transportation unless specifically waived by the Town Highway Superintendent.
Retaining walls shall be concrete gravity walls,
reinforced concrete cantilever walls, concrete crib walls or steel-bin-type
walls. Applicable New York State Department of Transportation standards
shall be followed. The use of gabion construction shall be specifically
approved by the Planning Board. When approved, applicable manufacturer's
construction standards shall be followed. All walls or structures
designed to retain earth fills shall be proportioned to withstand
pressure as given by Rankine's formula; but no structure shall be
designed for less than an equivalent fluid pressure of 30 pounds per
cubic foot. When highway traffic can come within a distance from the
top of the structure equal to 1/2 its height, the pressure shall have
added to it a live load surcharge pressure equal to not less than
two feet of earth.
Plain and reinforced concrete shall comply with
the Building Code Requirements for Reinforced Concrete (ACI 318) using
air-entraining Portland cement. Concrete shall develop a minimum twenty-eight-day
compressive strength of 3,000 pounds per square inch.
