Which type of footing is most commonly used when a column is placed near a property boundary, restricting footing extension on one side?

Explanation:

• Strap footing is used when a column is close to a property line, and its footing cannot be extended symmetrically on one side.

• It connects the eccentrically loaded footing to an interior footing using a strap beam, allowing the load to be distributed evenly and avoiding tilting.

Additional Information

Isolated Footing

• Definition: A footing that supports a single column.

• Shape: Usually square, rectangular, or circular.

• Use Case: When columns are well spaced and loads are moderate.

• Limitation: Not suitable near property lines if the footing can't be placed symmetrically around the column.

Combined Footing

• Definition: A single footing supporting two or more columns.

• Shape: Usually rectangular or trapezoidal, depending on column spacing and loads.

• Use Case:

  • When one column is near a boundary and another is close enough to share the footing.

  • Useful when isolated footings would overlap.

• Advantage: Balances load and prevents eccentricity.

Mat Footing (Raft Foundation)

• Definition: A large, continuous slab supporting multiple columns or an entire structure.

• Use Case:

  • When soil bearing capacity is low.

  • When building loads are heavy and closely spaced.

• Advantage: Distributes load evenly over a large area.

• Limitation: Expensive; not typically used just for boundary restrictions.