between abutments, and that this width should be left
quite unobstructed, for the river is subject to floods, which are
frequent, and very violent and sudden. For this latter reason an ordinary
form of arch, with the roadway above it, was inadmissible, since the
waterway would be seriously obstructed; the special form illustrated was,
therefore, carried into execution. The bridge, as will be seen from Figs.
1, 2, 3, and 7, consists of two main arched girders, with two vertical
sides in lattice work; these arches spring below the level of the roadway
and rise to a considerable height above it, in the center. The horizontal
girders carrying the roadway, are connected to the arches by verticals of
the form and section shown in the drawings. The longitudinal girders are
of double trellis, as will be seen by reference to Figs. 1, 12, and 16.
The following are the principal dimensions of the bridge:
Ft. In.
Clear opening between abutments 291 4
Rise of arch 32 93/4
Width of bridge 37 43/4
Depth of arched girders 4 7
[Illustration: BRIDGE OVER THE RIVER ADIGE, AT VERONA.
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