15 August 2002
Cover. Minimum concrete protection for reinforcement is as follows:
152.4 mm (6 in) where face of concrete will be in contact with soil.
76.2 mm (3 in) for formed or finished surfaces not in contact with soil.
50.8 mm (2 in) over bearing pile tops.
At piles intended as holddowns, and having a considerable length of
embedment in the concrete, place the reinforcement as in the first bullet
Reinforcing Bars. Reinforcement should have a minimum yield strength
of 275,790 kPa (40,000 psi), and conform to ASTM Specification A 615, Deformed and
Plain Billet-Steel Bars for Concrete Reinforcement, Grade 40. High strength, or special
large size reinforcement should conform to Grades 60 and 75. Consider use of epoxy
coated, stainless steel, cladded stainless steel, or galvanized reinforcement.
Foundations. Evaluate safe soil bearing capacity by methods set forth in
DM-7.01 Soil Mechanics and DM 7.02 Foundations and Earth Structures. Where the
safe capacity of the soil is exceeded, provide structural support. Types of structural
supports applicable to the foundation of drydock proper and to supplemental structures
are: timber piles, concrete piles, steel H-piles, pipe piles with open or closed ends, and
caissons. For pile capacities, analytical treatment, information on range of capacities
for various types of piles, and capacity of caissons, refer to DM-7.02 Foundations and
Load and Strength Reduction Factors. In design of reinforced concrete
structures, proportion members for adequate strength in accordance with provisions of
the latest edition of ACI 318, Building Code Requirements for Reinforced Concrete,
using load factors and strength reduction factors (phi) specified.
Service Load Stresses. Alternatively, nonprestressed reinforced
concrete members may be designed using service loads and permissible service load
stresses in accordance with provisions of ACI 318, Appendix B, Alternative Design
Buoyant Condition Increases. For a buoyant condition of a continuous
U cross section, which might be produced in a relieved or partially relieved dock
resulting from failure of the pressure relief system, or for construction stages, the
ordinary working design criteria may be increased 50 percent.
METHODS OF ANALYSIS