15 August 2002
Paved Road Network. This network provides access to the entire dock
area and should be capable of carrying trailer trucks, flatbed trucks, mobile track
cranes, truck cranes, and other heavy traffic.
Parking Facilities. Provide parking as space permits clear of the graving
dock operating areas.
Standard Gage Railroad Track. Where material for the graving dock
operations is delivered to the yard by rail, a standard gage track may be provided on
either side of the dock. At the dock, locate this track between the portal crane rails
nearest to the dock. This standard gage track may also be used for the operation of
locomotive cranes. At some yards, materials may be handled by heavy truck cranes
instead of locomotive cranes, and railroad tracks may not be required.
Use MIL-HDBK-1025/1 Piers and Wharves for track support design.
Portal Crane Track
Location. To minimize the required reach of drydock cranes over a
graving dock, locate crane rails as close to the edge of the coping as possible, but not
nearer than about 1.5 m (5 ft). Because they must withstand high weight concentrations
and shock loads, crane rails, unless supported directly on the dock walls, are usually
supported by concrete beams on closely spaced piles, or by continuous spread footings
generally tied in at intervals with the graving dock sidewalls. There are some locations
where trackage may be supported by ties and ballast. Portal cranes may be designed
to operate on either a two-rail track or a four-rail track. Space tracks far enough apart to
allow passage of railroad and truck traffic between outer rails of pairs of rails.