15 August 2002
Full Hydrostatic. For analysis of four basic conditions of loading, refer to
American Civil Engineering Practice, Volume II.
Fully or Partially Relieved. Where these drydocks have relatively thin
floors, concentrated ship blocking loads and wall reaction produce deflections resulting
in variations in foundation pressures and requiring methods of elastic foundation
analysis. The problem is to be treated as two-dimensional. For typical methods of
solution, refer to DM-7.02 Foundations and Earth Structures. The elastic foundation
method may be used to assist in estimating foundation pressures for the special loading
conditions discussed in section 5-6.
Computer Analysis. The Naval Facilities Engineering Service Center
has a three-dimensional computer program for analyzing or designing drydocks.
Basic Safety Standards. For general safety standards see OSHA Part
1915, Occupational Safety and Health Standards for Shipyard Employment.
Safety Features Peculiar to Drydocks. Observe the safety features
described in sections 5-9.2.1 through 5-9.2.7.
Coping Railing. It is necessary for coping railings to be removable to
avoid fouling lines when docking and undocking ships. The removal and replacement
must be accomplished with as little hazard as possible, because of the seriousness of
the accident should a person fall into an empty dock. Chain rail with removable
stanchions is often used, but maintaining adequate chain tension is a common problem.
Solid metal pipe or fiberglass railing, provided in 1.8-3.0 m (6-10 ft) sections for ease of
removal/reinstallation, is preferred.
Stairways. Use open mesh treads on all framed stairways. Use non-slip
treads for concrete stairways. Provide closing chains at top of steep, infrequently used
stairways. Preferably, stairways should have pipe handrails. Chain and stanchion
handrails may be used as an alternate.
Toe Guards. Provide toe guards at all handrails wherever possible. At
the coping edge, a curb may serve as a toe guard.
Obstructions to Mooring Lines. Keep the top of coping clear between
the edge of the coping and the line of capstans and bollards, except for luffing and
fairing line handling fittings.
Stepdowns in Tunnels and Culverts. Avoid unprotected stepdowns in
all unlighted tunnels and culverts. Use guardrails, or an arrangement of rails and
gratings, to protect personnel while still retaining the water carrying capabilities of the
tunnel or culvert.