(Continued)
Construction and Rehabilitation History
1964-
The jetties underwent major rehabilitation using the
1966
The new seaward ends of the
4,950- and 3,550-ft-long repair sections terminated 790 and 1,135 ft
from the original seaward ends of the north and south jetties,
respectively. The south jetty repairs consisted of a rebuilt gulf
side slope, a 200-ft-long head section, and a 250-ft channel side
spur located 550
landward of the head. The north jetty repair
section had the landward 2,410-ft channel side and adjacent (seaward)
2,250-ft gulf side slopes rebuilt. The final 300 ft were rebuilt as
a transition and 200-ft head section. The head sections had a crown
a 32-ft crown width and
side slopes.
elevation of
The 16- to 18-ton cover stone was placed as a double layer on the
side slopes and single layer on the crown. The 200- to 4,000-lb core
stone was partially supplemented with 0.5- to
filler stone (in
a section extending beneath the crown at
side slopes) for the
purpose of decreasing structure permeability. The 0.5-in. to 200-lb
blanket stone was placed in a 5-ft-thick layer and extended 50 ft
beyond the toe of the cover layer. The jetty trunk sections were
side slope. The crown extended
rebuilt to
mlt and a
two cover stones in width from the existing 12-ft-wide concrete cap
sections or 14 ft from the center line of the north jetty grouted cap
(1,800-ft section). The single layer of cover stone varied from a
minimum of 2 to tons at the south jetty landward end to a maximum
of 1 to 1 tons at the jetty seaward ends. The blanket layer was
6
8
placed in 3 - , 4-, or 5-ft thicknesses and extended 1
beyond the
0
toe of the cover layer. Prior to placing the core stone the existing
void spaces were chinked with filler stone. The filler, blanket, and
core stone size ranges were the same throughout the repair sections
(see above). The south jetty groin consisted of core stone placed to
ft mlt, a 10-ft crown width, and
side slopes. The core
stone was placed on a 5-ft layer of blanket stone which extended
1 ft beyond the toe of the core stone, The total cost of rehabili-
0
tation was ,367,000 and required 410,250 tons of stone. The jetty
design was based on Hudson's slope stability formula, depth- and
fetch-limited wave heights, and a maximum storm surge level of +13
mlt. The 18-ton maximum cover stone was inadequate for maximum
design conditions but was selected for practical and economic
reasons.
1967
Hurricane Beulah's passage in October displaced cover stone at
several locations, with an estimated 1 0 pieces missing or displaced
0
from each jetty. Near the landward ends of the jetties sand was
washing or piping under the concrete caps and into the ship channel.
It is not known whether this piping was due to the storm or if it had
been a previous problem. These sections were located from
to sta
on the north jetty and from sta
to sta
on
the south jetty (landward ends at sta
(Continued)
41
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