Table 2 (Continued)
Construction and Rehabilitation History
Date(
seaward end of the north jetty was completed in 1961 and within the
year was undermined by wave action resulting in part of the mono-
lith breaking off. The monolith was repaired by placing rocks
side slopes and grouting the rocks
around the head section on
with concrete. The elevation of the concrete at the north jetty
mllw and at the south jetty to +26 ft mllw at
was raised to +25
the tip. The heads were protected with 12-ton stones with a cover
layer of 100-ton concrete blocks.
Winter storm waves washed away most of the newly placed 100-ton
1965
concrete blocks.
The concrete monolith at south jetty was undermined and broken.
1970
Heads of both jetties were totally destroyed.
Rehabilitation of both jetties was completed. Concrete monoliths
were reconstructed, and 42-ton dolosse were placed around the sea-
1972
ward quadrant of both jetty heads. Four unreinforced, 1,271
reinforced, and
steel-fiber-reinforced dolosse were placed on
the north jetty; and 22 unreinforced and 1,423 steel-reinforced
dolosse were placed on the south jetty head. Dolosse (43-ton) also
were placed on the shoreward transition sections o f both jetty
heads. Two layers of dolosse were placed using a concentration of
1 1 dolosse per 1,000 sq ft of
Cost of this work was
,108,764. Model testing was conducted prior to these repairs
(Davidson
South jetty repairs using concrete and stone were completed at a
1973
cost of ,400.
.
1975
the site. Inspection trips subsequent to the earthquake revealed
fresh cracks along the south jetty running along the edges of the
crest and slope for a distance of about 800
on the channel side
and 300 ft on the seaward side. Blowout holes also were observed
at several locations on the south jetty. On the north jetty, three
of the dolosse had moved about 50, 100, and 150
from the place-
ment area, respectively. Only minor settling of the remaining
dolosse had occurred, and no cracking o r unraveling of the dolos
units was apparent.
1977
South jetty repairs using concrete and rock were completed. Ap-
proximately 15,000 tons of stone ranging from 1 to 20 tons were
used for these repairs.
The jetties were subjected to severe storms combined with high
tides and winds. On occasion, waves covered both jetties over
1978
their entire lengths. Waves also were observed breaking over the
dolosse and concrete monoliths of the jetty heads. North jetty
repairs using stone were completed at a cost of 0,000.
(Continued)
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