Pad footing are the foundation structures that are mostly made for the foundation of the column construction system. Pad footings transmit point loads from the columns into the ground. The ground plan of pad footings is mostly square, less often rectangular or circular. Square pad footings are designed especially for the centre load. The pad footings are economically and productively advantageous if their side is not more than half the axle spacing of the columns, otherwise grid, slab or pile foundations are more useful.

Vertical constructions such as partition walls, perimeter structures, or staircase walls are based on foundation lintels or foundation thresholds that carry the load on individual pad footings.

The shape, material and dimensional design of the pad footings depends on the anchorages of the columns or other structures mounted on the feet. pad footings can be one-stage or two-step.

Classification of pad footings according to the technology implementation:

• Monolithic pad footings
  • Pad footings made of plain concrete
  • Pad footings made of reinforced concrete
  • Pad footings interspersed with stones
• Prefabricated pad footings
  • Hollow (calyx) pad footings
  • Full pad footings

Monolithic pads are made of plain concrete or reinforced concrete, optionally as combined:

• Pads made of plain concrete are used only for small layout plan dimensions (up to 2 m of side size), for centrifugal loads and for bottom footing with permissible load capacities above 2 MPa. Surface of the pad is defined by the load and permissible bearing capacity of the foundation soil. The height of the monolithic pad is determined by the size of the lining and the displacement angle. If the pad height is greater than 1 meter, the pads are designed to be stepped. The concrete foot can be concreted directly into the formwork. Pads made of plain concrete can be concreted directly into the formwork.
• Pads made of reinforced concrete are designed for larger layout plan dimensions, eccentric loads and base soil with accessible stresses up to 0.15 MPa. Reinforced concrete pads are relatively low because the displacement angle tgα is 0.5 - 1. The top surface of the pads is most often skewed. If the angle of inclination of the upper surface is less than 35 °, the top of the pads can be concreted without formwork. At a higher slope, formwork is required. The pads are concreted into ready formwork, for which the excavation on each side needs to be extended by the necessary handling space. Below the reinforced concrete pads, it is necessary to make a concrete foundation layer with a thickness of 50 to 100 mm to protect the reinforcement against corrosion.

Pre-cast pad footings made of reinforced concrete or pre-stressed concrete are used for assembled skeleton structures. Prefabricated pad footings may have different ground planes (rectangular, circular, polygonal, star-shaped, etc.). The most widespread are the pads with rectangular cross sections. These pads are manufactured in two basic design variants:

• Hollow (calyx) pads footings or nesting pads have a recess into which a prefabricated column is mounted on a cement mortar bed, and after locking they are concreted.
• Full pads footings are manufactured as one-stage or multi-stage. Column connection with pad provides reinforcement anchor inserted into the opening in the pads and potting cement mortar. The reinforcement is welded to the shod foot of column.

Pre-cast pad footings are laid on the base panels or on monolithic load distribution slab. The dimensions are determined by calculating the column load and bearing capacity of the foundation soil. The bottom footing must be aligned with a layer of sand or base concrete at a thickness of 100 and 150 mm. The foundation lintels can be supported by the pad footings.

Lightweight continuous structures (walls of non-cellar light buildings, perimeter walls, etc.) can be based on a foundation lintel which load is transferred to the foundation block to the bottom footing in frost-free depth.

Strip footings are used to support both load-bearing and non-load-bearing walls from 6 N/m² - i.e. approximately 150 mm thick and 3 m high. Lightweight partitions and structures are placed directly on reinforced concrete. The minimum size of the strip footing is 300 x 300 mm. Columns are based on strip footings in cases where the pads are too large or in the case of the skeletons with unevenly laid ceilings.

Strip footing forms a continuous beam, which may be rectangular, stepped, plate or ribbed in cross-section. Depending on the material used, we can distinguish strip footings made of quarry stone, plane concrete and reinforced concrete.  Concrete and reinforced concrete structures may be monolithic or prefabricated.

The width of the strip footing (b) is determined by the load and admissible bearing capacity of the subsoil. The height of the base (h) is derived from the size of the foundation extension (a) and the size of the displacement angle and the permissible load of the suboil. For the calculation of the height of the strip footing, the relation can be used: h = a.tgα, where tgα is for the stone 2 - 3, for plain concrete 1,5 - 2 and for reinforced concrete 0,5 - 1.

Strip footings made of quarry stone are used only rarely. The most commonly used stone is marlite. Strip footings can be used for low-load walls. Strip footings can be made one or two steps.

Strip footings made of plain concrete are used for wall constructions. They can be single-stage (rectangular cross section) or graded at higher base heights. The plain concrete strips have a minimum size of 300 x 300 mm

Strip footings made of reinforced concrete are used for heavy loads transmitted to the foundations with less bearing and non-homogeneous subsoil. The shape of the reinforced concrete strips may be rectangular, with a sloping upper surface or a cross-section of the inverted T. Strip footings made of reinforced concrete are concreted either in longitudinal or transverse alignment with the supporting beams of the skeleton. The stiffness of the strips for large buildings can be increased by stiffening strip footings located perpendicular to the main strip footings. Below the reinforced concrete strip footings, it is necessary to make a base layer.

Strip footings assembled buildings can be made of prefabricated panels. Prefabricated strip footings are used when loading the foundation soil is from 0.2 MPa to 0.35 MPa. The prefabricated parts are made of concrete or reinforced concrete with dimensions graduated for different loads and up to 3 meters. The parts have a rectangular or trapezoidal cross-section. The pre-cast strip footings are put into a sand bed of 100-150 mm thickness, which equalizes the bottom of the excavation.

Grid fottings re formed by strip footings, generally perpendicular to each other. Footing grid are used for heavily loaded skeletal structures designed in non-homogeneous subsoil in soils with high compressibility, undermining or seismically unstable areas.

The foundation slabs distribute the load on the entire surface of the ground plan of the building so that the bottom footing is stressed more evenly than other types of foundations. Foundation slabs are used in inhomogeneous, low-load-bearing and extensively compressible base soil. The slabs are designed if the calculated width of the strip footing is so large that there is little soil between the concurrent strips. The slabs are used for the construction of high-rise buildings and for extremely heavy-load structures. The foundation slabs can also be used for groundwater foundation.

It is always necessary to consider the use of the foundation slab, since it is rather expensive and demanding for mass consumption and, especially in the case of insufficient reinforcement, is subject to failure due to the uneven settlement of the building.

The foundation slabs are made of reinforced concrete as straight, ribbed, grate, headed, shell or gable. Straight slabs have a constant height of 400 and 1200 m across the floor plan and are used at distances of supporting walls or columns up to 4 m. With the greater axial spacing of vertical structures or greater load on the slabs, it is preferable to reinforce the slabs with ribs that are better resistant to deformations. The rib can be placed above or below the slab. The advantage of a top ribbed slab is that it allows positioning between the ribs. The disadvantage is the need to create a formwork ribs and separate floor construction. The slabs with the lower ribs are not suitable for foundation below the water due to the complicated implementation excavation and waterproofing. Heavily loaded skeletal structures can be based on head or grate foundation slabs. The head slab is very advantageous both in terms of production and economy and is also the most commonly used. The only disadvantage is the protruding feet above the floor level. Instead of a slab, a monastery vault or slab reinforced with a beam system can be designed, which is more rigid than a simple slab.