Текст A
SHALLOW FOUNDATIONS
FIGURE 1
Shallow foundation is the term usually used when the type of foundation that transfers vertical loads by direct bearing on soil strata close to the bottom of the building and a relatively short distance below the ground surface is described. There are three basic forms of shallow foundations: the continuous, strip, wall footing; the individual column or pier footing; and the mat or raft foundation. Figure 1 shows a number of elements generally used in bearing foundation systems.
Foundation walls are typically built of concrete or masonry. The structural and architectural functions of foundation walls vary, depending on the type of foundation, the size of the building, climate and soil conditions, and whether or not they form a basement.
With no basement the walls are not actually walls. A principal difference relates to the construction of the building floor, whether it consists of a framed structure elevated above the ground, or concrete placed directly on the ground.
When a basement is required foundation walls are usually quite high. In a half-basement the basement floor is only a short distance below grade and the part of the basement wall above ground may be of different construction than that extending into the ground. If the basement floor is a significant distance below grade, major soil pressure will be exerted horizontally against the outside of the wall. In such a case the wall will function as a spanning element supported laterally by the footing or the basement floor at its lower end and by the building floor at its top. For buildings with multilevel basements, walls may become quite massive due to the accumulation of vertical load and the potential for considerable lateral soil pressure.
Notes:
accumulation n. накопление
continuous footing ленточный фундамент
half-basement n. полуподвал
multilevel adj. многоуровневый, многоэтажный
pier footing столбчатый фундамент