The STATNAMIC load test has been developed to meet the construction industry's demand for an accurate and cost effective method of determining the load bearing capacity of caissons and high capacity piles. Developed jointly by Berminghammer Corporation of Canada and TNO Building & Construction Research of the Netherlands, STATNAMIC can be used on any pile type with minimum pile preparation. Loading is perfectly axial and the relatively slow application and release of compressive forces eliminates tensile stresses, compressing the pile and the soil as a single unit. As a result, static load-displacement behaviour can be obtained.

Conventional static load testing methods for deep foundations are expensive, time consuming, and cumbersome. Dynamic load testing methods do not provide direct measurements, induce high accelerations, and load-displacement behaviour is controlled by the action of stress waves. STATNAMIC testing overcomes the practical difficulties of both static and dynamic load tests.

In STATNAMIC testing, solid fuel is burnt within a pressure chamber. As the pressure increases, an upward force is exerted on a set of reaction masses while an equal and opposite force pushes downward on the pile. Loading increases to a maximum before unloading by a controlled venting of the pressure. Built in instrumentation (load cell and laser sensor) record load and displacement during the entire STATNAMIC test.

STATNAMIC assembly is straightforward. All components are handled with a small hoisting machine. Reaction masses are sectional (2400 kg for the 5 MN device) and made of concrete, lead, steel, etc. Concrete reaction masses can be cast on-site and reused.

During a STATNAMIC test, measured signals from the load cell and laser sensor are digitally recorded by TNO's Foundation Pile Diagnostic System (FPDS). Over 2000 values of load and displacement are recorded. Load versus displacement results are presented immediately on-site, as well as graphs of load, displacement, velocity, and accelerations versus time. Straightforward methods of analysis are provided through easy to use software to determine any damping or inertial effects. Load-deflection behavoiur and the ultimate capacity of the foundation are clearly presented to the user.

In the example above, the STATNAMIC test mobilized the full capacity of the pile, providing 1.2mm of net settlement.

Today's taller buildings, heavier loads, and increased construction costs require the use of large-diameter, drilled pier foundation systems. As such, the demand for high capacity piles over 5.0 MN has increased dramatically.

Traditionally, static pile loading tests (to failure or twice design load) have been used to verify the geotechnical design parameters, pile load capacity, and, in some cases, the integrity of the pile. However, static pile loading test methods are expensive, time consuming, and cumbersome. Dynamic load test have been used, as well as, to predict static capacity and load-displacement behaviour. The dynamic response of a pile, however, is controlled by stress waves; the analysis of which requires highly experienced engineers. Dynamic load testing also creates tensile stresses which can cause pile damage in concrete piles.

STATNAMIC testing overcomes the practical difficulties of both static loading and dynamic load tests. STATNAMIC is capable of producing a given force using only 10% of the mass in an equivalent static test. During STATNAMIC loading, a perfectly axial load is applied for a duration of 120 milliseconds; long enough to compress the entire pile. Pile behaviour is not dominated by stress wave propagation and pile accelerations are on the order of 1 g. Load duration and loading rate are controlled by the vent height, amount of fuel, and reaction mass.