A Treatise On The Principles And Practice Of Dock Engineering

BRIDGE PIVOT AT VELSEN. 429 materially interféré with the working of the bridge. Further, owing to its slender proportions, it is very liable to fracture from shocks or impact due to abrupt stoppages and passing vessels. Accordingly, it must be weil protected. The advantage of the design lies in the faet that a high pivot identifies the point of support more nearly with the centre of gravity of the bridge, or even places the support above it, and so conduces to steadiness Æ^Ç.C f234ss?sa ipfest Fig. 405.—Bridge Pivot at Velsen. of movement and absence of surging. This type of pivot can, of course, only be adopted when the plane of the roadway is some distance above the lower flanges of the bridge girders. Sometimes the conical form of the pivot is more accentuated, as in fig. 406, which is the pivot of a bridge at Rotterdam. A is the socket on which the pivot rests after passing through the cast-iron bearing girder, B.