Foundations for Bridges and Buildings (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1914 edition. Excerpt: ...erected in lo-foot sections. The working chamber was 25 feet high, and had a roof consisting of a 2-foot oak diaphragm made of four thicknesses of timber, with a circular hole 2 feet in diameter closed by a cast-iron door. In the piers of the Glasgow bridge, which were sunk by the pneumatic process the diameter of the outer shell was 15 feet, the thickness of the shell at the base being inch and at the top T5, inch. The shaft.which was 3 feet 7 inches in diameter formed the inner cylinder, and this was removed before filling the working chamber and air-shaft. Almost no records exist of the use of the reinforced-concrete pneumatic cylinder caisson. In Art. 102 there is given an example of this type, in which the first part of the sinking was done by the open-caisson method and the latter part by the pneumatic process. Art. 102. Combination Cylinder Caissons With the cylinder caisson it is a simple matter to construct the cylinder to be used either as an open or a pneumatic caisson. This makes it possible to utilize the advantages of both methods of sinking, the open caisson being used for that part of the sinking in which the material can be dredged or pumped out, and the pneumatic process for that part where boulders or compact material is met with, and in finally preparing the foundation bed and placing the concrete filling in the working chamber. The caissons for the Merrimac River bridge, between Salisbury and Newburyport, Mass., were of this type. Each caisson consisted of an 8-foot diameter cast-iron shell, the metal being 1f inches thick and cast in 8-foot sections. These sections had inside flanges bolted together and a mixture of red lead and linseed oil was placed between the joints. The cylinders were sunk by inside dredging to...