1378

THEORY AND PRACTICE OF ENGINEERING

Book II.

afterwards : the span of the arches was about 75 feet, and their rise about j ; they werecomposed of three bent timbers, the lowest being of a greater depth than the others, andwere kept together by the binding-pieces which sustained the timbers on which the plat-form for the road rested.

The Bridge over the Meuse is 60 feet span, and consists of four arches, a section oft wo of which is shown in the diagram below, having the longitudinal timbers and springing

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Fig. 2263.

BRIDGE OVER THE MECSB.

plates placed above and below the three bent timbers : the entire width of the bridge beingabout 28 feet, the distance between the arches was scarcely 8 feet.

Bridge over the Rhone is another example of supporting the roadway on timber archesheld firmly by transverse timbers bolted together above and below, into which are framedradiating binding-pieces that abut against the under side of the longitudinal timbers.

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Fig. 2269.

THE RHONE.

2270.

uJUTEJ

Fig. 2271.

The plans of the piers and section are shown, as well as the contrivance above the piersor protecting them against ice or trees that may be carried down by the river.

Bridge built over an ann of the Necker , at H'urtemberg , about 63 feet span, has the roadway