Ryegate Design-Build Culvert Replacement

Ryegate, Vermont

D&K is the lead engineer for the $15.2 million dollar VTrans Ryegate STP CULV (10) design-build project, which replaces a deteriorated culvert conveying the Manchester Brook under US Route 5 and the Washington County Railroad. The existing undersized culvert has contributed to flooding of US Route 5 and the backwater jeopardizes the integrity of the roadway and rail embankments. The existing culvert is a deeply buried structure (over 60 ft under the railroad embankment) with steep embankments on both sides of the roadway and rail line. Partnering with the contractor, D&K has developed a solution that provides savings in initial construction costs, safer conditions for future inspections, better access for maintenance, improved aquatic habitat, and improved service life and constructability.

The structure consists of two 32-ft-wide, cast-in-place, reinforced concrete arch culverts beneath the roadway and rail line. The culverts are 141 ft and 128 ft in length and will have a 100-year service life, eliminate flooding potential, and greatly improve aquatic organism passage. The project includes a temporary rail bridge to allow culvert excavation below, and temporary track realignment and superelevation removal to minimize lateral forces of trains on bridge throughout construction. Complex design issues include designing a culvert to meet better than a 100-year service life; design of support for temporary roadway and rail bridges; design for significant slope stability issues; protection of the brook throughout construction; and limiting settlement between footings to 1 inch or less.