A Treatise On The Principles And Practice Of Dock Engineering

CHAPTER III. CONSTRUCTIVE APPLIANCES. Classification—Positive, Negative, and Auxiliary Appliances—Piling Apparatus —Hand, Steam, Electric, and Hydraulic Machines— Ram and Fall— Quiescence — Limit of Driving — Supporting Power of Piles — Concbete Mixers—Messent, Taylob, Carey-Latham, Sutcliffe, and Gravity Machines — Concbete Moulds—Block-setting Appliances—Excavators—French and German Machines—Ruston, Simpson-Porter, and Whitaker Steam Navvies— Hydraulic Navvy—Drilling Appliances—Hand and Machine Drills— Blasting Agents—Haulage and Traction—Dredgers and Hoppers—Suction, Ladder, Dipper, and Grab Dredgers—Buckets—Shoots—Tumblers—Power —Cost—Dams of Eabth, Timber, Stone, Concbete, and Ibon—Coffebdams— StEENGTH and StABILITY—PcMFS AND PuMPING—CRANES—OvERHEAD TrAVEL- LERS-Skips—Lewis Bars and Clips—List of Constructive Plant at Keyham Dock Works. The speediest and, at the same time, the most economical methods of carry- ing out projected works are points of the utmost importance to the engineer. Time and capital are alike too valuable to be utilised to any but their fullest extent. Hence some consideration of the various types of appliances used in dock construction, especially in regard to their capabilities, efficiency, and cost, will not be without both interest and advantage. Classification. -—A chapter which has to deal with a number of cliscon- nected items must perforce exhibit some break of continuity, and in order to minimise this effect and, at the same time, to link together the different sections, the following classification is proposed :—Positive appliances will include all those employed in definite constructive operations—that is to say, piling machines, concrète mixers, setting machines, and the like. Negative appliances will be understood to mean those engaged in the removal of existing obstacles and superfluous material, such as excavators and dredgers, boring apparatus and blasting agents. A third class, designated Auxiliary appliances, will include all those used in conjunction with each of the fore- going, indifferently and for either object, as dams, pumps, waggons, skips, and locomotives. The classification is, of course, purely artificial, but it will serve a useful purpose if it admits of the systematic treatment of a hetero- geneous subject. POSITIVE APPLIANCES. Pile Drivers and Driving. —The process of driving a pile generally con- sists in causing a heavy weight, called a ram or monkey, to fall from some height, in a series of blows, upon the head of the pile. For this purpose a