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Isolated Footing Reinforcement & Its Detailing

A structure is constructed on top of its foundations, which lay in the soil. The foundation is the base of a building or any such structure.

Concrete reinforcements pour inside, and these are placed in a ditch or conduit excavated by excavators. Soil bearing capacity tests before the foundation is constructed to determine what type of foundation should be built.

Structural design for footings begins with reinforcement detailing. Detailed footings provide structural support and ensure structural stability. It is important to properly detail reinforcement to cover topics like addressing durability issues at the cover, bar diameters, and the proper dimensioning of footings. Both plan and elevation drawings should include information about the foundation.

Minimum Reinforcement & Bar Diameter

There must be at least 0.12 percent reinforcement in each cross section. It is recommended that the main reinforcement have a minimum diameter of 10 mm./p>

Reinforcement Distribution in Footing

The reinforcement in RCC footings is distributed uniformly across the full width of the foundation. A two-way square footing offers uniform reinforcement across the width of the footing in both directions. Nevertheless, rectangular footings using two-way reinforcement installs in a long direction across the entire width of the footing.

The reinforcement, however, is distributed in the central band for short direction calculations. On both sides of the central band, the rest reinforcement is distributed equally in a short direction.

Concrete Cover of Reinforcement

For a footing that is in direct contact with the ground, the minimum reinforcement thickness should not be less than 50mm, and for a PCC for surface leveling, the minimum thickness should be 40mm. The excavation surface must cover with 75mm if surface leveling is not used.

Lap Splice

You should clearly show the length of the dowels and columns. Both the flexural reinforcement for the footing and the dowel reinforcement for the columns should be checked to prevent bond failures of the dowels and prevent failures of the lap splices that join the dowels to the column bars.

Dowel Reinforcement

The footing is reinforced with dowels so that it can be connected to the above column. It is recommended that in the design drawings, the development length of the dowel bars into the columns, as well as the isolated footing, be clearly specified.

Soil Bearing Capacity

Soil bearing capacity determines the size of a footing. Soil should be able to bear more weight than the unit area below footing to prevent settlement.

Gross bearing capacity refers to the total force acting at the base of the footing, which includes the footings self-weight, the weight of the column, and the pressure of any overburden around the footing. Taking into account the weight of excavated soil, the net pressure at the base of the footing can be calculated.

Detailing

Structural design for isolated footings begins with the reinforcement detailing. Detailed Isolated footings provide structural support and ensure structural stability.

In a good reinforcement detailing, the living cover is considered, the reinforcement should be based on the environment, the reinforcement diameters should be at a minimum, and isolated footings should be sized properly.

Wrapping it Up

An isolated foundation is preferred when the soil is sufficiently strong. Residential buildings generally use combined and isolated footings. For foundations and columns with overlapping footings, there is a small distance between them. The combined footing is preferred in these cases as it makes the structure more stable and economically viable.

It is indivisible from the construction of a foundation that footings are necessary. Using concrete and rebar reinforcement, they engineers. In footing, the aim is to provide the muse with adequate support while preventing settlement. There's a particular necessity for feet in poor soil conditions.

To get more details, watch the following video tutorial.

Video Source: Civilknowhow Tutorials

Isolated Footing Reinforcement & Its Detailing