Pile Driving Inspection Flashcards

What is the primary purpose of a 'driving criterion' or 'refusal' specification for pile driving?

Answer: To define the blow count per inch that indicates adequate bearing capacity has been reached

The driving criterion specifies the blow count (blows per inch or per foot) that indicates the pile has reached the required bearing capacity in the soil.

What does 'set' mean in pile driving terminology?

Answer: The penetration of the pile per blow of the hammer

Set is the penetration of the pile per hammer blow, typically measured in inches per blow or blows per inch, and is used to assess pile capacity during driving.

What information must be recorded on a pile driving log for each pile?

Answer: Hammer type, blow counts, driving time, tip and cutoff elevations, and any splices or interruptions

A complete pile driving log must record hammer identification, blow counts at regular intervals, driving interruptions, tip elevation, cutoff elevation, splice locations, and any anomalies.

What is a 'pile splice' and when is it required?

Answer: A connection joining two pile sections when the required length exceeds a single pile section

A pile splice joins two pile segments when the required pile length exceeds the available single-piece length, and must be made using approved methods (welding for steel, mechanical connectors for concrete).

What is the purpose of a 'follower' in pile driving?

Answer: An extension piece used to drive a pile when the hammer cannot reach the pile head

A follower is an extension piece placed between the hammer and the pile head to allow driving when the pile head is below the reach of the hammer, such as in water or after cutoff.

What is 'pile heave' and why is it a concern?

Answer: The upward movement of previously driven piles caused by driving adjacent piles

Pile heave occurs when driving adjacent piles causes previously driven piles to move upward, potentially reducing their capacity and requiring re-driving.