Table 20
Bar Breakwater
Gloucester Harbor, Mass.
Date(
Construction and Rehabilitation History
The 2,250-ft-long Dog Bar breakwater, consisting of a rubble stone
1906
substructure below mlw and a stone-block superstructure, was con-
structed to protect Gloucester Harbor from sea and heavy swells from
the south (Figure 23, plan view). The rubble-mound substructure was
built to an elevation of 0 ft mlw, where the mound width was 31 ft,
and a composite sea-side slope of
a harbor side slope of
and
below and above -12 ft mlw, respectively. The
to tons, except on the
substructure stone sizes ranged from 500
seaward side slope where the stone weighed to tons. The super-
structure was built up at
side slopes to an elevation of
+17 ft mlw where the crown width was 10 ft. The stone blocks were
placed horizontally, in overlapping stair-step fashion, with their
lengths perpendicular to the breakwater axis. The blocks were 2 to
3 ft high, 2 to 6 ft wide, to 10 ft long, and weighed to 12 tons
each. A row of rubble stone, weighing about 5 tons each, was placed
along the superstructure seaward toe. A total of 231,760 tons of
stone was placed for a total cost of 8,000.
Minor repairs were made to the superstructure in 1931,
1940
1939, and 1940. The work (approximate totals in parentheses) in-
cluded resetting (2,000 tons) and replacing (1,000tons) stone
blocks, placing rubble stone (7,000tons) on the seaward face
stone blocks to act as buttressing for the upper courses of stone.
The total repair costs were ,700.
A breakwater inspection showed the stone block superstructure was in
1962
good condition with only localized areas needing repair. The sea-
side armor stone, placed during 1931-40, was in poor condition with
several large cavities and a general subsidence along the entire
breakwater length.
Repairs were made to the breakwater superstructure, and 10,920 tons
of 6- to 12-ton armor stone were placed on the sea side between
1966
Displaced stone blocks were reset from
(landward end) and
to
and
to
Total cost of the repairs was
,400.
Breakwater inspections, taken over this period, showed a gradual
deterioration of the sea-side armor stone at several locations. Most
1978
of the damage was on the outer half of the breakwater.
(Continued)
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