WHARVES AND WHARF CON STRUCTION. The modern methods of wharf construction vary but little (except as to minor &tails) from the methods of the ancients. The process of constructing timber piers or wharves as practised in all of the ports of the Atlantic and Pacific seaboards is as follows: Piles of the best obtainable timber (general) Y Pine or oak) are first driven to a solid foundation into the material forming the bottom of the harbor; these are designated as standard piles and are spaced from 6 to 10 feet from centres loqgi tuditially and transversely (see Fig. 1), ac cording to the desired carrying capacity of the wharf. These piles are than sawed off at the proper height above the tide level and on their Kips (and fastened thereto with drift bolts) are placed timbers, often of yellow pine about 12 inches square. These timbers are known as the caps of the wharf. On these caps are placed the stringers or floor beams. They are generally four inches thick and vary from 12 to 16 inches in depth. according to the load to be sustained. They are commonly fastened to the caps of the wharf with spikes. The stringer system is placed about two feet nit centres on this superstructure; the covering from three to six inches in thickness fastened with the ordinary commercial spike of requisite length. After this portion of the wharf is finished nothing remains but to protect the same, either with a system of piles driven along the side used for mooring vessels (usually called fender piles and which are fastened to the superstructure of the wharf) and are sometimes additiohally protected by wearing strips of timber and plank. (See Fig. 1.) A wharf projecting out from the centre longitudinally and about five feet trans versely; the outer pile in each bent is cut off one foot below the grade of the balance and iu capped with a longitudinal sub-cap 12 inches square. The balance of the standard piles in each bent are cut off to conform with a crown of four inches in a 60-foot wharf and are capped transversely with 12 X 12-inch timbers. The piles after being stayed into position are mortised into caps having tenons seven and one half inches wide longitudinally with the caps, three and one-half inches thick and three inches long; the caps are also drift bolted to each standard pile with a wrought-iron bolt one inch square. (In San .Francisco, the eats are merely drift-bolted to each pile with a one-inch round iron drift bolt; no tenons are used). The stringer system, or as they call it there, rangers, are 12 X 12-inch timbers, spaced five feet apart, or so as to come directly over each standard pile, the outside stringers being composed of two pieces. The
covering of the wharf is of two of four inches each. In place of fender piles, the outside standard piles are utilized for fenders of 8 X 12-inch white oak ti extending from the sub-caps to the line of low water ; there are also two lines of horizontal fenders of 8 X 12-inch oak ex tending the entire length of the wharf (with the exception of the four outer baits); one of these i; fastened to the sub-caps and the other to the backing block; between these vertical fenders there are placed intermediate fenders of the same material but reaching merely be tween the two longitudinal fenders. In place of mooring piles there is used a cast-iron moor ing bit. The four outer bents of the wharves are spaced about 20 feet from centre to centre. They consist of a double row of piles, each row containing the same number of piles as are rin,t itunt lune vi the harbor is generally fo-ced or braced by means of brace or batter driven on both sides of the wharf (see 1 ) at an angle of about 35 degrees with tis perpendicular and they are fastened to the csr,ide stringer as shown The above describes rOi ,rr particularly the wharves as constructed or the Pacific Coast and in use in San Francisco since 1880. These wharves are 100 fe•• in width and about 600 feet in length New York Wharves.-- III Ness' Y“rk City. in wharves of the same area, contractors use about double the number of standard or bear ing piles (with the exception of the four outer beats) as were used in those of San Francisco. Tile piles are driven 10 feet from centre to under the regular caps, or making this row of double the carrying capacity of those caps. The cud piles in each of these bents and the sheath ing are so arranged that they present a rounded edge to the current. This is covered for a dis tance of four feet with an armature of boiler steel one-half inch in thickness and six feet in height, securely fastened to piles and sheathing. The wider spacing of the outer bent, the addi tional bracing and armature plates are for pro ttction against floating ire The timber for superstructure used there is what is known as hard yellow pine. The standard piles are gen erally of spruce and vary from 50 to 60 feet in length. The wharf timbers rarely exceed 30 feet in length.