Culverts – DuBois & King, Inc.

Converse Road Culvert

Study, design, and construction phase engineering for Bridge No. 110/141. D&K completed an alternatives evaluation and recommended replacement of the existing culvert. The firm also provided permit application assistance, prepared final engineering plans and specifications, assisted the Town during the bid phase, and provided the Town with construction administration services.

The original bridge was a 18-foot-long corrugated metal arch with stone headwalls; the culvert was suffering from corrosion, settlement and scour, and had a Federal Sufficiency Rating of 47.4%. The project received funding through the NHDOT Municipal Bridge Aid program and followed the NHDOT Local Public Agency (LPA) process.

First Crown Point Road Culvert

D&K provided study, design, and construction phase engineering for Bridge No. 069/164. D&K completed an alternatives evaluation and recommended replacement of the existing culvert. The firm also provided permit application assistance, prepared final engineering plans and specifications, assisted the Town during the bid phase, and provided the Town with construction administration services.

The original culvert was a 14-foot-long corrugated metal pipe culvert with concrete headwalls and wingwalls; the culvert was suffering from corrosion, missing bolts and sagging. The previous culvert had a Federal Sufficiency Rating of 47.9%. The project received funding through the NHDOT Municipal Bridge Aid program and followed the NHDOT Local Public Agency (LPA) process.

Archertown Road Culvert

Study, design, and construction phase engineering for Bridge No. 095/118 on Archertown Road. Services included alternatives evaluation and recommendations to replace the existing bridge, state and federal permit application assistance, preparation of final engineering plans and specifications, assisting the Town during the bid phase, and providing the Town with construction administration services.

The previous Archertown Road Culvert was a 15-foot-long metal plate arch culvert with inadequate (nonexistent) approach guardrails, substandard bridge rail, and a Federal Sufficiency Rating of 69.6%. Deficiencies included a low load carrying capacity (6-ton) weight restriction, “one lane” bridge width, and failing stone headwalls and wingwalls. This bridge was on the NHDOT Redlist.

A detailed study is has been performed that evaluated cost-effective replacement options. DuBois & King provided design and construction phase services for a new 28-foot-long, two lane, 3-sided precast rigid frame replacement structure. The project received funding through the NHDOT Municipal Bridge Aid program and followed the NHDOT Local Public Agency (LPA) process.

Ryegate Design-Build Culvert Replacement

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.

Wheelerville Road Culvert Replacement

As part of a Master Services Agreement, D&K provided project management, FEMA coordination, design, and bid document preparation for repairs to municipal infrastructure damaged by Tropical Storm Irene. For the Wheelerville Road Culvert, D&K provided design engineering services for the replacement of a double barrel culvert that was displaced by 5 ft. The new three sided 10 ft by 5 ft precast box structure provides a natural channel bottom for fish passage and meets environmental regulations.