396 DOCK ENGINEERING.
upper floor, supported on cast-iron columns 20 feet apart, is placed at a
height of 16 feet, and is extended so as to form an exterior gallery, 11 feet
9 inches in width. Examples of single-storey sheds are given in fig. 380.
Fig. 379. —Shed at Marseilles.
Fig. 380. —Sheds at Marseiiles.
Ihe following are stated to be the dispositions found to be most suitable
for sheds at this port :—
The shed to be enclosed on three sides; on the fourth, or dock, side to
have doorways alternating with solid panels. Sliding doors in two leaves,
with angle-iron frames, iron sheeting, and wood border. Roofs, in spåns
not exceeding 100 feet in width, carried on cast-iron columns, serving as
downspouts. Irusses, 16 feet apart, with framed iron principals and wood
purlins. Roof covering of files, with a double lantern, 12 feet wide, on each
slope, astride ridge.
Fig. 381.—Shed at Calais.
Other French Ports.
The sheds at Calais (fig. 381) are in two equal spans of 65 feet 6 inches,
with overhangs of 13 feet on each side.