What is the main advantage of shallow foundations?
They use the bearing strength of upper soil layers and are generally less expensive.
What is the main disadvantage of shallow foundations?
They depend on adequate strength near the surface and may not work well where weak soils are present near grade.
What is the main advantage of deep foundations?
They can transfer loads to deeper high-strength soil or bedrock, making them suitable where upper soils are weak.
What is the main disadvantage of deep foundations?
They are more expensive than shallow foundations.
What is a slab-on-grade foundation typically used for?
Light construction.
What is a mat foundation?
A structural slab that extends under essentially the entire building footprint to spread loads over a large area.
What is a raft foundation?
A hollow structural slab under the building footprint.
How do slab, mat, and raft foundations compare in cost and use?
Slab-on-grade is usually the simplest and least expensive for light construction; mat foundations cost more but spread heavy loads over weak soils; raft foundations are more complex and used where a structural hollow slab is beneficial.
What are the two main load transfer approaches for piles and piers?
End bearing and friction.
What is the difference between friction piles and bearing piles?
Friction piles transfer load by skin friction along the pile surface, while bearing piles transfer load to a strong layer or bedrock at the tip.
What materials can piles be made from according to the slides?
Wood, steel, and concrete.
What is a pile cap?
A concrete cap cast over a group of piles to support and distribute a column load.
What is a pier, and how can its bearing area be increased?
A pier is a drilled deep foundation element, and its bearing area can be increased with a belled base.
Why is differential settlement a problem?
Because uneven settlement can damage the building, unlike uniform settlement which many buildings can tolerate.
What is the purpose of foundation drainage?
To manage surface and subsurface water around foundations.
