The Theory, Practice, and Architecture of Bridges of Stone, Iron, Timber, and Wire (Volume 1-2); With Examples on the Principle of Suspension - Softcover
Synopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1856. Excerpt: ... DESCRIPTION OF THE PLATES. CENTERING FOR BALLATER BRIDGE, ACROSS THE DEE, ABERDEENSHIRE. Plate 1. The centering here shown is that used for the middle arch of Ballater Bridge. This bridge occupies the place of a former structure which was swept away by a flood in 1799. The present bridge was erected by the late Mr. Telford, and opened for the passage of carriages in the year 1809. The bridge is situate on the Dee, and is distant 40 miles from Aberdeen: it has five arches, the centre one being 60 feet in span. The bridge is of granite, and the contract price was £3300, but the work is said to have entailed a heavy loss upon the contractor. As a design, this centering presents no peculiarity worthy of notice, except that in order to guard against damage from ice, and to avoid obstructing any floating object in the river, which at this place has a very rapid current, the main horizontal beams of the centering are elevated 6 feet above the springing of the arch. The surface of the water in this, as in most of Mr. Telford's bridges, nearly coincides with the level of the springing, so that the timber of the centering thus disposed would be out of reach of the water. The principal parts of this centering are the two main rafters extending from the springings of the arch to the top of the king-post; the vertical king-post into which the two rafters are framed and to which they are strongly secured by bolts passing through an iron plate with radiating arms; and the main tie beam secured to the king-post by an iron strap, and bolted to the rafters at the crossing. From the foot of the king-post proceed two struts inclined to the horizon at an angle of 40. These struts are framed into the curved timbers which support the covering boards. Two additional struts ...
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