(Continued)
Construction and Rehabilitation History
Repairs were made at a total cost of 6,700 using 16,940 and
1950-
13,570 tons of stone on the north and south jetties, respectively,
1951
The jetties were repaired, and three spurs were constructed on the
channel side of the south jetty. The majority (80 percent) of the
1957
jetty repairs used 8- to 13-ton cover stone; the remainder was mostly
25 to 2,000
and the spurs were built using 25-lb to 10-ton
(quarry-run) stone. The spurs were placed about 1,000
apart with
the outermost approximately 2,400
from the jetty's seaward end.
Each spur was about 200
long and extended seaward, offset from the
jetty axis at a 30- or 60-deg angle. The spurs were needed to reduce
scour and undermining of the jetty caused by tidal flows. Stone
quantities were 19,300, 52,640, and 72,870 tons for the spurs, north
and south jetties, respectively. The total repair and construction
costs were ,145,500.
Sections of the north and south jetties (2,150 and 355
long, re-
1958-
1959
spectively) were capped with concrete. These sections extended sea-
ward from the existing caps, and it appears they terminated at the
jetties' existing seaward ends. The condition of the outer 640- and
1,100-ftsections of the north and south jetties could not be de-
termined from information at hand. The concrete was grouted through-
out the cover stone void spaces lying between 0 and
ft mlt (the
existing crest elevation). Prior to placing concrete, large voids
were filled with 5- to 50-lb chinking stone. A total of 7,290 cu yd
of concrete and 2,800 tons of stone was placed at a total cost of
7,
1961-
The passage of Hurricane Carla in September 1961 caused significant
1962
damage to the seaward ends of the jetties. The outer 300 ft of the
north jetty, including the outermost 250 ft of concrete cap, essen-
tially was destroyed. In 1962 the jetties were surveyed and in-
spected in preparation for planned rehabilitation. The concrete caps
essentially were intact, although numerous cracks and sections of the
caps had subsided. However, this was not a true indication of their
general condition. There was significant subsidence of the side
slope armor and underlayer core stone creating void spaces beneath
the caps and exposing core stone on the steepened side slopes. The
rehabilitation was recommended based on expected failure of several
jetty sections, under storm conditions, leading to a loss of channel
protection and increased shoaling. Scour and undermining were con-
sidered major sources of jetty deterioration. Center-line elevations
varied from -10 to -35 ft mlt and from -10 to -20
mlt on seaward
8 0 and 1,000-ft sections of the north and south jetties, respec-
0
tively. Scour holes were evident at their extreme seaward ends.
(Continued)
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