Richard Phené Spiers and Leveson Francis Vernon-Harcourt

“ Special provisions have to be made for the foundations of piers where the ground is soft for some depth, or loose water-bearing strata are encotmtered, and especially where the piers of large bridges crossing rivers have to be constructed under water. In soft ground, bearing piles driven down to a firm stratum, and surmounted by a planked floor or a layer of concrete, provide a convenient foundation for a pier; and in places where timber is abundant, wooden cribs filled with rubble stone or concrete have been used in the United States for raising the foundations for piers out of water. ”

“ When, however, a river-bed consists of silt, sand or other soft materials extending down to a considerable depth, brickwork wells are gradually sunk to a firm stratum by removing the material within them with grabs, and on them the piers are built out of water ”

“ Timber piles are best suited for withstanding the shocks of vessels at landing stages, at which places they are generally used, but since they are subject to the attacks of the teredo, and expose a considerable surface to the waves, iron piles are generally adopted for the main portion of these piers. ”