A Treatise On The Principles And Practice Of Dock Engineering

WHARFS AT GREENOCK. 299 details. The length of the pier is 2,844 feet, the width is 35 feet for three- fourths of this length and 41 feet for the remainder. The top of the pier is 9 feet above high water, and there is a parapet wall, 9 feet high by 9 feet wide, inainly, but 14 feet wide at the outer end, running along its entire length. The weight of the blocks used on this pier was 15 tons ; they were set on a bagwork foundation by a 20-ton block-setting crane worked by a gas engine. The crane revolved completely, and could set a 20-ton block 64 feet in advance of its leading wheel. The foundation was constructed in the same manner as that at Roker Pier. Wharfs at Greenock. The wharfs constructed along the frontage of the River Clyde, at Greenock,* between the eutrances to the East and West Harbours and westward of the West Harbour, in order to obtain a greater depth of water than existed at the old quays, are known as the Steamboat Quay and the West Quay respectively. These wharfs were erected parallel to and 25 feet back from an improved channel way, adding about 5,380 super- ficial yards to the old irregular quays—which are much used for coasting traffic—and a depth of 28 feet at high water has been provided in front of them. Borings, taken along the line of the new work, showed that a firm stratum, fit for quay wall foundations, was only reached at great depths, attaining 70 feet below high water in one or two places, and therefore timber work was adopted. A trench was first dredged along the front line of the new work, and, after driving the piles, a bank of whinstone rubble was deposited, to serve as a toe to the filling between the new and the old work. To increase the resistance of the main piles to outward thrust, wrought-iron shields, 5 feet by 31 feet, were bolted to the faces of the front piles before driving, and then driven down so that their tops were 2.1 feet below the level of the finished dredged bottom. Sheet- ing piles and horizontal planking were placed along the line of the front piles to retain the bank of rubble stone, and for the retention of the filling behind the back line of main piles, a double row of sheeting piles was driven, the lower ends of which extended about 4 feet into the rubble bank, and between the sheeting piles, a wall of 8 to 1 concrete was brought up to the deck planking. The greenheart front and back piles, 14 to 16 inches square, 8 feet apart, and driven into the hard clay, are joined by half-timber ties, and wliole-timber struts were inserted between the piles, and the ties and struts bolted together. The quay surface is planked with 3-inch Gardnerised fir planking, with whinstone pitching laid thereon, on a bed of Portland cement mortar. The face of the quay is protected by segmental rubbing irons. * Kinipple on “ Greenock Harbour,” Min. Proc. Inst. C.E., vol. cxxx.