2QÔ
DOCK ENGINEERING.
bands, each consisting of eight curved plates, 16 feet 6 indies long and
4 feet in height. Both sides and bottom were strengthened with ribs of
lattice girders. Across the bottom, eaoh along the centre of a row of plates,
ten girders, 2 feet in height, were placed, 3 feet 9^ inches apart from
centre to centre. The sides were supported by fifteen circular girders
placed horizontally, and varying in breadth from 1 foot 9 inches to 1 foot
6 inches, and also by twelve vertical girders from 2 feet to 1 foot 9 inches
Seale, 21 feet to 1 inch.
Figs. 242 and 243.—Pierhead at Madras.
in width. The vertical girders were set at equal distances apart, and only
their inner flanges were continuous throughout the height of the caisson, the
outer flanges being arranged in sections between the horizontal girders.
The inner flange consisted of a 3-inch by 3-inch by g-inch angle iron,
connected at a single joint by a bar cover. To these girders the side
plating was fixed by j-inch rivets at 5-inch pitch, the tiers being rivetted
together with f-inch rivets at 2J-inch pitch and arranged telescopically,