Guo architectural designs and construction Ltd.

29/06/2026

29/06/2026

29/06/2026

Another day in the life of an architect

29/06/2026

Proposed Bawork Cultural mesurm 🇨🇲🇨🇲🇨🇲

02/12/2025

18/10/2025

Footing Design Basic (Isolated, Combined, Raft)

Footings are structural elements that transfer building loads safely to the soil. The type of
footing used depends on the load of the structure and the soil’s bearing capacity. Properdesign ensures stability, safety, and prevents settlement.

1.Isolated Footing

Used when individual columns are spaced far apart. Each column has its own footing.

Types: Square, Rectangular, Circular.

Design Steps:

• Calculate column load.

• Determine footing area (Load / SBC).

• Check for bending, shear, and bearing capacity.

• Provide reinforcement in both directions.

2.Combined Footing

Used when two or more columns are close or when one column is near the property line.

Types: Rectangular, Trapezoidal.

Design Steps:

• Combine loads from both columns.
• Determine centroid and shape.
• Design for uniform soil pressure.
• Reinforce for bending and shear forces.

3.Raft or Mat Footing

Used when loads are heavy or soil bearing capacity is low, covering almost the entire area
under the structure.

Types: Flat plate, Beam and Slab, Cellular raft.

Design Steps:

• Compute total load and soil area.
• Analyze slab using plate theory.
• Provide reinforcement top and bottom.
• Check punching shear around columns.

4.Design Considerations (as per IS 456 & ACI Code)

• Safe Bearing Capacity of Soil (SBC)

• Minimum thickness (150–300 mm)

• Clear cover (50–75 mm)

• Reinforcement spacing and development length

• Settlement and differential settlement control

■ Conclusion:

Footing design ensures stability and prevents structural failure. Selection of proper
type—isolated, combined, or raft—depends on soil strength, column spacing, and load
magnitude.

Related Hasgtag: