NCCCO Dedicated Pile Driver flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Batter pile

A pile driven at a planned angle from vertical. The specified batter is verified in two directions before driving, and the leads are adjusted to match the angle.

Cut-off elevation

The finished top elevation of a driven pile after the excess length is cut away. It is set by the project drawings and confirmed by survey before cutting.

Single-acting diesel hammer

A diesel hammer that fires once per cycle, lifting the ram with combustion gas and letting gravity return it. Rated by ram weight and stroke.

Vibratory driver

A driver using rotating eccentric counterweights to create vertical vibration. Driving force depends on eccentric moment and frequency, and it works best in granular soils.

Pile driving analyzer

An instrument measuring force and velocity at the pile head during driving. The case method estimates capacity and integrity from those records, not from static testing.

Follower

A section that transmits hammer energy to a pile whose top is below the reach of the leads. Its added mass changes the energy delivered, so criteria are adjusted.

Pile gate

A hinged or sliding guide in the leads that holds the pile plumb and aligned with the hammer before and during driving.

Pile pick points

Locations on a pile designated by the manufacturer for lifting. Lifting at other points can crack concrete piles, so the handling diagram is followed.

Refusal

A condition where the pile stops penetrating under the specified blows per inch. It is verified with the engineer before cut-off, since it may indicate an obstruction.

Load radius

The horizontal distance from the rig's center of rotation to the center of gravity of the load. It sets the chart capacity and grows as a long pile is stood up.

Gross versus allowable load

Gross capacity comes from the chart at the working radius. Allowable pile load is gross capacity minus the weight of leads, hammer, pile, and attachments.

Outrigger float

The pad or float under an outrigger beam that spreads load into the ground. Its position and bearing area must match the configuration used in the load chart.

Wind sail area

The exposed area of a standing pile that catches wind. As the pile is raised, sail area grows, and manufacturer wind limits determine when driving stops.

Rated capacity limiter

A device that warns and limits the rig when the load approaches the charted capacity. It is tested before work and never used as a substitute for the chart.

Anti-two-block device

A device that prevents the hook block from contacting the boom tip. It is tested each shift, and a failure stops operations until repaired.

Wire rope inspection

A pre-shift check for broken wires, kinks, bird-caging, corrosion, and diameter loss. Rope is removed when it meets the rigging standard's removal criteria.

Sling angle tension

Leg tension equals load divided by the number of legs times the sine of the angle from horizontal. Shallow angles sharply increase tension in each leg.

Hydraulic injection hazard

Fluid escaping under pressure can pierce skin. Pressure is released before opening a fitting, and a suspected injection is a medical emergency.

Lockout during maintenance

The hammer is lowered, blocked, and its energy source locked out before service. The rig is never serviced with a suspended load.

Designated signal person

The single crew member who directs the operator by agreed hand signals or radio. The operator stops on a stop signal from anyone, then resumes only on this person's signal.

Exclusion zone

The area around the driving location kept clear of all but the working crew. It is sized from hammer, leads, and pile radius plus a margin for breakage.

Tag line

A rope used to control pile rotation from outside the swing radius. Personnel never steady a suspended pile by hand.

Lost radio signal

Loss of communication between signal person and operator. The operation stops until communication is restored, since the operator may not move on voice alone.

Utility locate limits

A locate ticket marks approximate buried facilities. Pile locations are verified by hand digging or vacuum excavation, since the ticket alone does not clear the driving area.

Ground bearing check

Verification that the soil under outriggers or crawlers can carry the rig's load. Soft fill and backfilled excavations require mats or cribbing sized by calculation.

Geotechnical report

The soil borings and bearing stratum data that set planned pile length and hammer energy. Pile length and driving criteria are matched to it before the first set.

Approach distance to lines

The required minimum separation from energized overhead lines. The utility confirms de-energizing, or the rig maintains the distance for the line's voltage.

Rig leveling

Setting the rig level on stable ground with outriggers fully extended or crawlers fully bearing. An out-of-level rig changes radius and invalidates the chart.

Boom configuration check

Confirmation that boom length, angle, and counterweight match the chart being used. Changing any of these requires re-evaluating capacity before the next lift.

Power line contact response

The operator stays in the cab and warns others away until the utility confirms de-energizing. The crew does not touch the rig during contact.

Instability response

If an outrigger sinks or the rig tips, lower the load and stop the swing before correcting the ground. Leveling is never attempted under a suspended load.

Stop-work condition

An unexpected event such as refusal, lost hammer stroke, or a pile moving off line. Work stops until the cause is evaluated and corrected.