Foundation Contractor Exam

CA D30 Pile Driving/Pressure Foundation Contractor Exam Questions And Correct Answers (Verified Answers) Plus Rationale2026 Q&A| Instant Download Pdf

What is the primary purpose of pile driving in construction?

• To create a decorative feature
• To support heavy loads by transferring them to deeper soil layers
• To reduce soil moisture
• To improve aesthetic appeal
• To support heavy loads by transferring them to deeper soil layers

Rationale: Piles are structural elements used to transfer building loads to

stronger soil or rock layers beneath weaker surface soils.

• Which type of pile is made by driving preformed concrete, steel, or

timber elements into the ground?

• Cast-in-situ piles
• Precast driven piles
• Augered piles
• Micropiles
• Precast driven piles

Rationale: Precast piles are manufactured off-site and then driven into the

ground, unlike cast-in-situ piles which are formed in place.

• What is the function of a pile cap?
• To anchor piles to prevent lateral movement 1 / 3

• To connect pile heads and distribute loads to multiple piles
• To prevent soil erosion around piles
• To serve as a temporary support during construction
• To connect pile heads and distribute loads to multiple piles

Rationale: Pile caps are reinforced concrete elements that unify the tops of

piles and evenly transfer structural loads.

• Which factor primarily affects the load-bearing capacity of a pile?
• Color of the pile
• Soil type and properties
• Length of the construction schedule
• Weather conditions only
• Soil type and properties

Rationale: The soil’s density, composition, and bearing capacity directly

influence how much load a pile can safely carry.

• Which pile type is suitable for driving in dense clay or sandy soils

without causing excessive vibration?

• Timber piles
• Steel H-piles
• Concrete pre-cast piles
• Screw piles
• Screw piles

Rationale: Screw piles are designed to be installed with minimal vibration

and are effective in clay and sandy soils.

• What is a common problem when driving piles into very dense soil?
• Excessive moisture accumulation
• Refusal or pile bounce
• Color change in the pile
• None of the above
• Refusal or pile bounce

Rationale: Refusal occurs when a pile cannot penetrate further due to

dense soil or rock, causing bounce during driving. 2 / 3

• Which instrument is used to measure the blow count when driving a

pile?

• Theodolite
• Pile hammer
• Pile driving analyzer (PDA)
• Dynamometer
• Pile driving analyzer (PDA)

Rationale: PDA instruments measure blow counts, stresses, and pile

behavior during driving.

• What is the standard unit of pile bearing capacity?
• Newton-meter (N·m)
• Kilogram-force (kgf)
• Kilonewtons (kN)
• Liters
• Kilonewtons (kN)

Rationale: Pile bearing capacities are usually expressed in kN,

representing the force the pile can support.

• In pile driving, what does “splicing” mean?
• Cutting piles to adjust length
• Connecting two piles to extend the length
• Coating piles with protective material
• Removing damaged pile segments
• Connecting two piles to extend the length

Rationale: Splicing is necessary when the required pile length exceeds the

standard pile length.

• What is the typical purpose of using timber piles in foundations?
• For temporary scaffolding only
• For aesthetic wooden structures
• For transferring moderate loads to soft soils
• For landscaping
• / 3