Pile Driving Inspection Flashcards
7 cards from real CTQP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Pile Driving Inspection flashcards as text
What information must be verified on the pile driving equipment submittal before driving begins?
Answer: Hammer type, rated energy, stroke, and cushion material specifications
The equipment submittal must confirm hammer type, rated energy, operating stroke, and cushion specifications to ensure compatibility with the pile type and driving requirements.
A diesel hammer is operating with very short strokes and low blow counts. What does this likely indicate?
Answer: The hammer is not developing full rated energy due to light resistance
A diesel hammer requires sufficient resistance from the pile to compress fuel and fire properly; light soil resistance causes short strokes and low energy transfer.
What is the significance of the 'elastic compression' (C1 or Ec) value in the Engineering News (EN) formula?
Answer: It accounts for the energy lost in compressing the pile cap and cushions
Elastic compression in the EN formula accounts for temporary elastic shortening of the pile, cap, and cushion system, distinguishing it from permanent set of the soil.
Which condition requires the inspector to immediately halt pile driving and notify the engineer?
Answer: Driving deviation exceeds maximum allowable tolerance limits
Exceeding maximum allowable pile deviation (out-of-plumb or out-of-position tolerance) requires stopping work and engineer notification to evaluate structural and design impacts.
What is the primary purpose of PDA (Pile Driving Analyzer) testing during construction?
Answer: To measure driving stresses and evaluate pile capacity using wave equation analysis
PDA testing uses strain gauges and accelerometers to measure force and velocity during driving, enabling CAPWAP analysis to evaluate pile capacity and driving stresses in real time.
When inspecting a timber pile, what visible defect would be cause for rejection before driving?
Answer: Knots that reduce the cross-sectional area by more than 33% at any section
Knots or defects that reduce the net cross-sectional area by more than one-third at any point compromise structural capacity and are grounds for rejection.
What does 'driving criteria' for a pile project typically specify?
Answer: The minimum blow count per foot or required tip elevation, whichever is more restrictive
Driving criteria establish the minimum blow count per unit penetration and/or the required tip elevation, and piles must satisfy the more restrictive of the two conditions to be accepted.