How does a dynamic pile load test work?

A free-fall weight generates a stress wave in the pile. Strain and acceleration are measured at the pile head. Bearing capacity is derived from the wave curve and the pile impedance.

What is the difference between CASE and CAPWAP?

CASE delivers a quick estimate directly on site. CAPWAP fits a pile model mathematically to the measured signal and separates shaft friction and base resistance. CAPWAP is more precise, CASE is available immediately.

How large must the drop mass be?

As a guide value, one to two percent of the expected pile resistance. That is why we keep weights from 7 t to 14 t available.

Can bored piles be tested dynamically?

Yes, if the concrete has hardened sufficiently and the pile head is prepared for the impact load. For high verification requirements, we recommend calibration against a static load test in the same ground.

How long does the construction schedule stand still?

Usually a few hours. Several piles in one day are the normal case, not the exception.

Service

Dynamic load test

Drop weight up to 14 t, measurement at the pile head, model analysis per CAPWAP. Bearing capacity in hours instead of days, with no compromise on the standard.

The principle

A stress wave says more than an assumption.

A free-fall driving weight hits the pile head and generates a stress wave. Strain and acceleration are measured at the pile head, the pile impedance Z = E · A / c connects both.

The pile is treated as an elastic rod with one-dimensional wave propagation. Strain gauges deliver the force from the deformation, accelerometers deliver the velocity curve through integration. By comparing both independent measurements we separate the downward travelling force wave from the one reflected by shaft friction and base resistance.

Bearing capacity, integrity and pile length result from the signal. For a reliable statement, we recalculate every measurement in the CAPWAP model.

CASE method

Directly on site: range of the static ultimate load, integrity, pile length, rough distribution of shaft friction.

Result on site

CAPWAP analysis

Signal matching in the model: static ultimate load for compression and tension, load-displacement curve, shaft friction and base resistance separated, cross-section changes.

Model analysis

Driving monitoring

Measurement during driving. Driving energy, stresses in the pile, bearing capacity development over depth.

PDA in operation

Ductile piles (modular piles)

Driven piles made of ductile cast iron tubes, extended module by module via plug-in sockets. The length follows from the driving resistance. The dynamic test records bearing capacity and driving stresses on the finished pile.

modular system

Further pile types

Precast reinforced concrete driven piles, steel tube and steel section piles, full displacement and bored piles as well as micropiles. Drop weight and pile head preparation are matched to the pile type.

drop weight by pile type

Our service

Equipment, measurement, analysis, report.

Provision of the special free-fall device as a driving rig
Two own special free-fall weights, 7 t to 14 t, matched to the expected pile resistance
Preparation of the pile head and application of the sensors
Measurement of strain and acceleration, wireless transmission
Evaluation per CASE directly on site
CAPWAP model analysis in the office, documented and traceable
Test report per EA-Pfähle and DIN EN ISO 22477-4