CBP Structural Systems and Foundations

Question 1

What is the most common foundation type used for single-family residential construction in the United States?

Accepted Answer

Poured concrete footing and foundation wall

Answer

Pile foundation

Answer

Mat or raft foundation

Answer

Caisson foundation

Question 2

What is the primary purpose of a vapor barrier installed under a concrete slab-on-grade?

Accepted Answer

To prevent ground moisture from migrating up through the slab

Answer

To insulate the slab from cold ground temperatures

Answer

To improve the compressive strength of the concrete

Answer

To act as a termite barrier under the foundation

Question 3

Why must footings be placed below the frost depth in cold US climates?

Accepted Answer

To prevent frost heave from shifting the foundation when soil freezes and expands

Answer

To keep the concrete from cracking in cold weather

Answer

To avoid disturbing frozen soil during excavation

Answer

To maintain consistent soil temperature around the footing

Question 4

What does 'soil bearing capacity' refer to in foundation design?

Accepted Answer

The maximum load per unit area that soil can support without excessive settlement or failure

Answer

The ability of soil to drain water away from the foundation

Answer

The depth to which soil must be compacted before pouring footings

Answer

The resistance of soil to erosion during construction

Question 5

What is a grade beam foundation?

Accepted Answer

A reinforced concrete beam at or near grade that transfers structural loads to piers or piles below

Answer

A concrete beam used to level sloped building sites

Answer

A horizontal beam installed at the top of a foundation wall

Answer

A pre-cast beam used in modular home foundations

Question 6

What is the structural role of reinforcing steel (rebar) in concrete foundations?

Accepted Answer

To resist tensile forces that plain concrete cannot withstand on its own

Answer

To increase the compressive strength of the concrete mix

Answer

To speed up the curing process by conducting heat

Answer

To provide a bonding surface for waterproofing membranes