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.
West Street Reconstruction
Project started with an alternatives analysis to determine the best option for reconstruction or relocation of a 1.3-mile portion of West Street, which was partially destroyed by flooding. Alternatives included closing the road permanently, reconstructing on the existing alignment, and relocating on one of three different alignments. D&K engineers proceeded to developed preliminary engineering, final design, and contract documents for the preferred alternative, which was to reconstruct the road on the existing alignment. The scope of services included field survey, development of line and grade, partial relocation of the adjacent stream, streambank stabilization, coordination with VT ANR and USACOE, design of a new precast concrete box culvert, and quantity and cost estimates. The project was considered an emergency action and was cost-shared between the Towns, the State, and FEMA. Services included:
Alternatives analysis
Hydraulic and hydrologic study
Preliminary engineering
Bridge culvert design
Topographic survey
Conceptual, preliminary, and final design
Stream relocation/stabilization
Construction observation
Permitting
Final design
Bid phase services
Contract documents
West Street Culvert Replacement
Evaluation, design, and construction-phase services for the replacement of an undersized stream culvert designed to promote aquatic organism passage and sediment transport. The existing 3-ft diameter culvert had inadequate hydraulic capacity, which led to significant sediment deposition upstream and scour downstream. Downstream scour left the outlet perched above the channel, forming an obstacle to aquatic organism passage. Following a geomorphic assessment to determine natural channel dimensions, D&K engineers identified and evaluated several alternatives. The selected option was a 14-ft-wide precast concrete box culvert with bed retention sills. Services included:
Coordinating and meeting with State regulators
Conducting a stream geomorphic assessment
Completing a topographic site survey
Computing peak stream flows and simulating flows with HEC-RAS
Designing a replacement culvert with bed retention sills
Preparing plans and specifications
Providing bid-phase and construction inspection services
West Danville Powerplant Repair
A failed penstock disabled the powerplant, eroded the site, and destabilized and destroyed sections of the powerhouse at Green Mountain Power’s West Danville hydroelectric facility. DuBois & King conducted an inspection of the failed penstock, power station, and project area; reviewed technical specifications of the penstock pipe; coordinated with the engineers associated with the original project; and provided design for the repairs. Project deliverables included:
An analysis of conditions leading to the failure
Design for stabilization of the site and foundation
Design for reconstruction of the powerhouse superstructure
Design incorporated a removable roof section for maintenance
Weirs Beach Boardwalk Rehabilitation
A severe flood event washed out 120 ft of the boardwalk, undermined the adjacent scenic railroad track, and caused the boardwalk embankment slope to fail. The original boardwalk was constructed in 1848 as a passenger platform for New England tourists arriving by train to Lake Winnipesaukee.
The City retained DuBois & King to design the repair for the damaged Weirs Beach Boardwalk section and to design upgrades and improvements to the entire 960 ft boardwalk to protect against future surface and high groundwater impacts after soil borings indicated that the entire boardwalk and railroad embankment was unstable.
DuBois & King engineered a design sufficient to handle the live load of the railroad that could be built during winter conditions within funding limits and schedule constraints. The design and construction was completed within 7 months, during winter conditions, and within the $1.13 million budget.
The design addressed the unstable slope, high ground water potential during flooding events, and provided a Cooper E-80 live loading for the railroad with sheet piling retaining walls with deadman anchors. The new underdrain/closed drainage system directs stormwater to a 200 ft treatment swale/retaining wall to create water quality improvements. Design features included new railings, stairways, crosswalks, and lighting. Reduced project cost by salvaging steel from the damaged boardwalk, utilizing recycled composite decking material, and specifying light fixtures that minimize light pollution.
Improved boardwalk is an economic centerpiece providing a safe link between the City beach, City docks, railroad station, restaurants, businesses, and shops.