pile

In building construction, a postlike foundation member used from prehistoric times. Piles transfer building loads down to a suitable bearing stratum when the soil mass immediately below a construction is unsuitable for the direct bearing of footings (see foundation). Piles support loads either by bearing directly on rock or suitable soil or by developing friction along their very ample length. In modern civil engineering, piles of timber, steel, or concrete are driven into the ground to support a structure; bridge piers and building foundations may be supported on groups of piles.