15 August 2002
of National Oceanic and Atmospheric Administration (NOAA), and to the local historical
Storm Potentialities. Ascertain potentialities of a site. These data have
a bearing on the determination of the freeboard height of a drydock and also on the
design of temporary construction work. Consider designing for at least a 100-year-
Wind Effects. Include a study of prevailing winds and their velocities,
fetch of water involved, and the length and height of waves. When these data are
combined with tide records, they indicate the expected probable high water conditions.
Wind Records. The wind effects may influence the design of fenders or
moorings contiguous to a drydock. Refer to NOAA wind records for areas of the United
Water and Air Temperatures. Approach body of water temperature
ranges are important in designing heating and ventilating systems, coolers, cathodic
protection systems, and any systems utilizing the water. Air temperature data are
required for similar reasons. Obtain water and air temperature in the vicinity from
NOAA and the local historical records.
Water Chemical Content. The chemical content of water is subject to
pollution when a drydock is located on a river. When water is supplied by wells or well
points from soil layers permeated by other than seawater, the chemical content is not
known. The corrosiveness of the water must be determined for design of pipes,
coolers, any equipment utilizing the water, pumping equipment, and drydock pressure
relief systems. Refer to MIL-HDBK-1005/7A Water Supply Systems.
Features. Drydocks generally have diverse and varied types of
foundation designs, which encompass the whole gamut of soil and foundation
engineering. Designs are found in the complete range of such engineering, from the
simplest spread footing to a complex elastic mat. Consequently, soil investigations
must be especially thorough and complete in the determination of a great variety of soil
Borings. Examine all available records of borings in the vicinity of a
proposed site. The scope of previous borings will help determine the program extent for
additional borings. For soil investigation procedures, refer to DM-7.01, Soil Mechanics.
Depths of Borings. Overall or mean soil pressures under drydocks are
not great; therefore, for areas under the main body of a dock, borings need not be as
deep as for other structures where load concentrations are severe. Where a drydock is
likely to be the relieved type, the depths of borings should be sufficient to allow proper
analyses of percolation problems. Where piles, either the bearing or holddown types,
might be used, boring depths should adequately indicate the soils to be penetrated.