Which element creates a mechanical interlock between footing and foundation wall to resist movement?

Which element creates a mechanical interlock between footing and foundation wall to resist movement?

• A. Dowel
• B. Groove
• C. Keyway
• D. Tie

Answer: (C)

The idea being tested is how to lock two concrete parts together so they can’t slide apart under load. A keyway does this by creating a mechanical interlock: a groove in the footing (or a matching projection in the wall) that fits with a corresponding shape, so the wall and footing act as a single unit. That interlock increases resistance to movement and helps transfer forces across the joint, making the connection much stronger than a flat, unkeyed surface. Dowels are pins used for alignment or to transfer shear, but they don’t provide the locking interlock between the wall and footing. A plain groove wouldn’t lock by itself without a matching protrusion to form the key. A tie serves to hold pieces together but doesn’t establish the locking joint at the footing-wall interface.

The idea being tested is how to lock two concrete parts together so they can’t slide apart under load. A keyway does this by creating a mechanical interlock: a groove in the footing (or a matching projection in the wall) that fits with a corresponding shape, so the wall and footing act as a single unit. That interlock increases resistance to movement and helps transfer forces across the joint, making the connection much stronger than a flat, unkeyed surface.

Dowels are pins used for alignment or to transfer shear, but they don’t provide the locking interlock between the wall and footing. A plain groove wouldn’t lock by itself without a matching protrusion to form the key. A tie serves to hold pieces together but doesn’t establish the locking joint at the footing-wall interface.