I
with the construction of rubble-mound jetties in the
Also completed
during the
were the steel sheet-pile structures (dikes) located on the
Gulf Intracoastal Waterway at Port Bolivar and Port O'Connor.
6. Concrete capping was first used in the early
at Sabine Pass,
Galveston, and Freeport but in each case was limited to placement toward the
and early
additional
landward end of a single jetty. During the
concrete capping was used on both jetties at each of these projects. The
Aransas Pass jetties were capped with concrete, and asphalt capping was placed
on the Galveston jetties. These caps were rectangular or trapezoidal in cross
section and were placed on top of the existing armor stone which itself was
repaired or chinked with stone prior to capping. In the
concrete was
placed at the Brazos Island and Aransas Pass jetties. These sections varied
from the previous caps in that the concrete was integrated directly into the
cover stone layer, forming a homogenous section of concrete and armor stone.
7. The period from 1962 to 1966 marks the era of maximum construction
of new and existing breakwater and jetty structures. Constructed at this time
were the breakwaters at Palacios and the jetties at Matagorda and Port Mans-
field. Major portions of the jetties at Sabine Pass, Point Bolivar,
ton, Port O'Connor, Aransas Pass, and Brazos Island were rehabilitated; and
the Freeport jetties received minor repairs. Subsequent efforts include the
construction of breakwaters at Port Aransas in 1973, the Colorado River
jetties (which include a rubble-mound weir section) completed in 1986, and
rehabilitation of the Brazos Island north jetty during the
8. Cross-section geometry and structure composition have been fairly
consistent since at least 1962. Crown elevations vary between
and
ft
mean low tide (mlt), and crown widths range from 8 to 20 ft. Side slopes are
typically from
to
on trunk sections and
to
on head
sections. Various sizes of granite stone are used in the section, beginning
with a bedding layer of 0.5-in. to 200-lb stone and varying from 2 to 5
in
thickness. This bedding layer has, in turn, acted as an apron by extending
it, typically 5 to 50 ft beyond the cover layer toe. Recently, toe protection
stone has been used in place of the extended bedding layer. Equal in size to
the core stone, it buttresses both the bedding and cover layers. The core
stone typically varies from 200 to 1,000 lb (but can be up to 4,000 lb on head
sections) and, to decrease permeability, is supplemented with 0.5- to
filler stone, The geometry of the combined core and filler stone extends
8
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