The Viaduct Works' Handbook
Forfatter: Henry N. Maynard
År: 1868
Forlag: E. And F. N. Spon
Sted: London
Sider: 108
UDK: 624.3
Being A Collection Of Examples From Actual Practice Of Viaducts, Bridges, Roofs, And Other Structures In Iron; Together With Tables Of Prices, Weights, And Other Information Useful To Engineers In Design And Estimating Wrought And Cast-Iron Work
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58
the floor girders, vertical bracings formed of T iron, placed diagonally,
one end of each being fastened to the upper or floor girders, whilst
the other end is made fast to the lower or bracing girders; there are
two bars in this manner crossing each other in each space between
the piles, both transversely and longitudinally. The floor is com-
posed of wood joists, 13 inches by 6 inches, placed 3 feet 1 inch
apart, and bolted to the girders, over which is nailed 4-inch wood
planking. The total weight of iron in this portion of the work is
about 478 tons of cast and 133 tons wrought-iron, or about 4 tons
per square of 100 superficial feet. The jetty portion is composed of
11 main girders, each 35 feet long, placed transversely about 15 feet
apart, each girder being supported by four cast-iron screw piles, of
12 inches diameter, screwed 20 feet into the ground. Lighter longi-
tudinal girders, and bracing with floor, &c. ; the same as described
above. The iron in this portion of the work is about 130 tons cast
and 65 tons wrought, or nearly 25 cwt. per foot run.
IRON ROOFS.
In the general acceptation of the term “iron roof” it in-
cludes all roofs in which the framing is of iron. They may be
covered with slates, tiles, zinc, galvanized iron, &c., with or without
woodwork interposed. The most durable coverings are those of
slates and tiles. “Duchess ” slates are generally employed with
iron framing. They are each 24 inches by 12 inches. 1000 of
them covers ten squares of 100 superficial feet, and the weight
of 1000 is about 60 cwts. They are attached by copper bands
to angle-iron laths; and the tiles called “pantiles.” These are re-
tained in place by small projections moulded on their under sur-
faces, and by the weight with which they overlap each other. They
are about double the weight of slates, but are preferred in some
cases. In respect of ventilation, they are convenient for many
manufactories, the numerous interstices between them affording, as
they do, apertures for the egress of heat and vapour, and they
are less liable to be broken by heat from below, and hence are