FOUNDATIONS AND PILES

Figure 1-6.—Nomenclature of a fixed the center line. A space of approximately one-quarter inch should be provided between the planks to allow for swelling, to provide water drainage, and to permit air circulation. The minimum thickness of decking is 3 inches in all cases; however, when the required thickness of plank decking exceeds 6 inches, then a laminated type of decking should be used. FOUNDATIONS AND PILES That part of a building or structure located below the surface of the ground is called the foundation. Its purpose is to distribute the weight of the building or structure and all live loads over an area of subgrade large enough to prevent settlement and collapse. A pile is a slender structural unit driven into the ground to transmit loads to the underground strata. It transfers loads to the surrounding underground strata by friction along its surface or by direct bearing on the highway bridge superstructure. compressed soil at or near the bottom. A bearing pile sustains a downward load and may be driven vertically or otherwise; however, when a bearing pile is driven other than vertically, it is known as a batter pile. Another type of pile is the sheet pile. It is used to resist lateral soil pressure. The following discussion is intended to introduce and familiarize you with some of the common types of foundations and piles that you may be required to include in your construction drawings. FOUNDATIONS In general, all foundations consist of three essential parts: the foundation bed, which consists of the soil or rock upon which the building or structure rests; the footing, which is normally widened and rests on the foundation bed; and the foundation wall, which rises from the foundation to a location somewhere above the 1-5