Portsmouth, NH Mechanic Street Seawall Replacement Underway
Contractor ACK Marine recently began to mobilize for replacement of the historic Mechanic Street Seawall (also known as the LaCava Wharf) in Portsmouth, New Hampshire.
The Mechanic Street Seawall is a former bridge abutment with a history of deterioration, displacement, and interim repairs. This replacement project, which was designed by Tighe & Bond, was initiated by a City-wide evaluation of municipal seawalls. Our team provided inspections and assessments of the existing conditions to develop a basis of design. The geotechnical borings indicated that the Mechanic Street site was underlain by deep soft clay and organic fill soils and the decision was made to reconstruct the new seawall on an H-pile supported foundation.
In addition to the H-pile foundation, the new seawall includes an exterior granite block face with reinforced cast-in-place concrete support. The exterior granite facing will incorporate the reuse of existing stone, to the extent possible, to replicate the historic appearance while meeting modern load capacity needs.
AKC Marine was awarded the $1.15M contract for demolition and reconstruction of the seawall with construction expected to be completed by December of 2021.