The City of Dover, New Hampshire owns Central Falls Dam in downtown Dover, originally built for powering the mills. Subsidence at Fish Ladder Park was the first sign the southern wingwall had issues and the park behind the wall was fenced off for public safety concerns. Tighe & Bond was selected as the consultant to evaluate the historic granite wall, which quickly transitioned to fast-tracked replacement design, environment & historical permitting, bidding and construction phase services.
A gravity wall design utilizing ReCon blocks was selected due to the large size of the blocks and the ability to build the block portion of the wall as high as 32 feet with vehicular live load surcharges. Footings for the block wall were cast-in-place concrete on the irregular bedrock surfaces. This gravity wall design and rockfill backfill was well suited to the challenging restricted site, irregular bedrock and winter construction adjacent to a waterfall with icing conditions.