Figure 1-10.—Types of concrete piles.Bearing PilesTimber bearing piles are usually straight tree trunkswith the limbs and bark removed. These piles, if keptcontinuously wet, will last for centuries; however, theyare used for low design loads because of theirvulnerability to damage while they are being driven intothe ground. The small end of the pile is called the tip;the larger end is called the butt. Timber piles range from16 to 90 feet in length with a tip diameter of at least 6inches. The butt diameter is seldom less than 12 inches.A steel bearing pile might be an H-pile (having anH-shaped cross section). These piles are usually used fordriving to bedrock. A steel pile can also be a pipe pilewith a circular cross section. A pipe pile can be either anopen-end pile or a closed-end pile, depending onwhether the bottom end is open or closed.Concrete piles, such as those shown in figure 1-10,may be either precast or cast in place. Most precast pilesused today are pretensioned and are manufactured inestablished plants. These piles are made in square,cylindrical, or octagonal shapes. If they are being driveninto soft or mucky soil, they are usually tapered.Cast-in-place piles are cast on the jobsite and areclassified as shell type or shell-less type. The shell typeis formed by driving a hollow steel tube (shell), with aclosed end, into the ground and filling it with concrete.The shell-less type is formed by first driving a casingand core to the required depth. The core is removed andFigure 1-11.—Steel sheetpiling.Figure 1-12.—Wood sheet piles.is thenthe casing is filled with concrete. The casingremoved, leaving the concrete in contact with the earth.Sheet PilesSheet piles, made of wood, steel, or concrete, areequipped or constructed for edge-joining, so they can bedriven edge-to-edge to form a continuous wall orbulkhead. A few common uses of sheet piles are asfollows:1. To resist lateral soil pressure as part of atemporary or permanent structure, such as a retainingwall2. To construct cofferdams or structures built toexclude water from a construction area3. To prevent slides and cave-ins in trenches orother excavationsThe edges of steel sheetpiling are called interlocks(fig. 1-11) because they are shaped for locking the pilestogether edge-to-edge. The part of the pile between theinterlocks is called the web.A wood sheet pile might consist of a single, double,or triple layer of planks, as shown in figure 1-12.Concrete sheet piles are cast with tongue-and-grooveedges for edge-joining.1-7
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