460

HISTORY OF ENGINEERING.

Book I.

The arches are light and elegant, and remarkable for their boldness and little rise; thevoussoirs are admirably proportioned, increasing in depth towards the abutments, where

Fig . 4G0.

tSECTION OF PIER.

greater strength becomes necessary ; the abutments are admirably constructed, the severalcourses which receive the thrust or pressure of the arches being made to radiate to the centreof the circle, from whence the segment of the arch is struck.

The section through the arch exhibits the foundations, sheet piling, and manner that thecrown supports the roadway, which has a footway on each side, and paved channel to col-lect the water which falls upon the bridge, and which is conducted into pipes and carriedoft' below. The piles are shod with iron, and driven till they come into a hard bed ofgravel, and the cofferdams were securely tied together with iron bars, which could bescrewed tighter, when necessary, by means of the nuts at their ends.

Hyde Park Bridge , erected from the designs and under the superintendence of Mr. GeorgeRennie, is a beautiful structure of three arches, each 40 feet span, with a versed sine of

ELEVATION OF PART OF HYDE PARK BRIDGE,

4 feet 10 inches; the radius from which the arches are struck was 45 feet,and the round ofthe segment is 42 feet. It was commenced in 1824. The construction does not materiallydiffer from the bridge last described.

Fig.462.

SECTION.