D&K’s Laconia Main Street Bridge Rehabilitation Project was announced as the “Overall Winner” of the 2016 ACEC-NH Engineering Excellence Awards, also recognized as the Category Winner for Structural Systems, signifying the year’s most outstanding engineering achievement. The announcement was made at the EEA Awards luncheon held on Thursday, March 17^th in Manchester. D&K also received the Water Resources Category Winner for the Robin Hood Dam Rehabilitation.

Laconia Main Street Bridge
Investigation, evaluation of alternatives, and design for rehabilitation of three independent concrete deck and steel stringer multi-span bridge structures that serve as a crossing of the Winnipesaukee River and support a complex intersection in the center of Laconia. As the predominant access in and out of the downtown area, the heavily traveled bridge is an essential component of the area’s infrastructure with traffic volumes of 10,000 vehicles a day. The design strategy was to merge the three separate bridge structures to function and move as one structure. The project reconfigured the intersection to improve traffic calming and pedestrian amenities. Construction phasing was developed to maintain travel for vehicles and pedestrians at all times.

Robin Hood Dam Rehabilitation
The Robin Hood Dam is a 120-year-old structure that impounds a 6-acre pond within Keene’s Robin Hood Park, a 130-acre woodland and recreational area. The dam did not meet current dam safety standards, and the NHDES Dam Bureau issued a letter of deficiency (LOD) requiring the City make a number of immediate and long-term improvements to the dam. A major issue was inadequate hydraulic capacity. DuBois & King implemented a first-of-its-kind technique (in New Hampshire) of armoring the dam embankment with articulated concrete blocks (ACBs), allowing the strengthened embankment to pass 2 ½ times the 100-year storm event, rather than increasing the height of the dam and redesigning the outlet structure. This approach achieved the hydraulic capacity requirement, reduced construction costs, maintained the current water level, and minimized unwanted changes or modifications to the park.

This month’s edition of Civil Engineering Magazine highlights the world’s first accelerated testing facility for full-scale bridges: the Bridge Evaluation and Accelerated Structural Testing Lab (BEAST).

The BEAST was designed by a team of Rutgers engineers and other bridge experts, with assistance from Applied Research Associates, Inc. (ARA). ARA constructed some of the massive components of the BEAST, especially a set of parallel steel I beams 120 ft long by 7 ft deep, at its plant in Randolph, VT. DuBois & King supported ARA with civil/site design, permitting, and structural engineering services including design of concrete abutments and foundation design for the environmental simulation enclosure. Site engineering included utility relocations, coordination of electrical design for 1200 KVA and as-built survey of the rail system. Click on the article link below to read more about the design and the future of testing for America’s bridges.

Read the article in: Civil Engineering Magazine (Feb. 2016)

D&K designed repairs for the Waitsfield Covered Bridge which have been completed. Improvements included:

• removal of the former sidewalk and replacement with a new self-supporting sidewalk on widened abutments
• replacement of rotting floor beams
• replacement of the timber wearing deck
• repairs to the abutments
• repairs to the roof
• improvements to approach railings and signing

The project also included the complete reconstruction of Bridge Street between Main Street and the Covered Bridge. This work included:

• new pavement and subbase
• replacement of the sidewalks
• new curbing
• new drainage pipes
• the installation of decorative benches, bricks, and street lights

With the widening of the abutments on the downstream side of the bridge, the Town of Waitsfield is going to be installing decorative railings so the public can use the areas behind the wingwalls as scenic overlooks.