Foundations with a connecting cantilever (strap) beam: which type of foundation uses a cantilever beam to join two individual footings to balance eccentric loads?

Introduction / Context:When a column is close to a property line, its isolated footing may experience large eccentricity. A strap (cantilever) beam can connect this footing to an interior footing, transferring moment and balancing soil pressure. Identifying this system is a fundamental foundation engineering task.

Given Data / Assumptions:

• Two separate pad footings supporting two columns.
• A connecting beam carries bending to equilibrate eccentricity.
• Soil pressure under both pads intended to be uniform/non-negative.

Concept / Approach:A strap footing (cantilever footing) consists of two isolated footings joined by a rigid beam (strap). The strap does not bear on soil; it transmits moment and shear between the pads to keep resultant loads within kerns. A combined footing is a single enlarged footing under both columns. A raft is a large mat supporting multiple columns. A strip footing supports a continuous wall, not individual columns.

Step-by-Step Solution:Recognize the cantilever beam between footings → strap beam.Confirm that pads remain separate; hence not a combined/raft footing.Therefore, the correct term is “strap footing.”

Verification / Alternative check:Textbook diagrams show property-line column connected to interior column via a strap to realign resultants.

Why Other Options Are Wrong:

• Combined footing: a single slab under both columns.
• Raft: large mat under many columns.
• Strip footing: for walls, not isolated columns.

Common Pitfalls:

• Confusing strap with combined footing due to plan similarity; the presence of a rigid beam between distinct pads is the key.

Final Answer:strap footing