Statnamic load test
Statnamic is a combination of static and dynamic and also aims to determine the geotechnical capacity associated with the load subsidence behaviour of a foundation pile.
When using the Statnamic method a reaction mass is launched by means of a rapid combustion of a specific fuel in the pressure chamber between the ballast and the pile head, causing the pile to be briefly (heavily) loaded. The launched reaction mass is than being captured by a hydraulic system in a frame so it does not fall back on the pile head. During the launch the force in the pile head is measured with an electronical pressure meter as a function of time and the displacement of the pile head is automatically measured with an optical measuring device.
The advantage of dynamic test compared to a static load test is the fact that with a relatively small (falling) weight a relatively large force can be generated, so that transport and building up a frame with ballast is not necessary. The major disadvantage is that the measuring results can be 'polluted' by dynamic inertia effects and any creep effects can not be detected. Strictly speaking, one speaks of a dynamic test if the length of time that the load is present (the pile driving blow), is shorter than the travel time of the resulting shockwave introduced into the pile towards the pile tip and back to the pile head.
With a Statnamic test the load is quasi-static: the load (the launch of the reaction mass) is only briefly present, but considerabily longer that the above mentioned travel time of the wave. In this manner Statnamic on one hand eliminates the main disadvantage (pollution by inertia effects) while on the other hand the main advantage of a dynamic test (with relatively little weight relatively high loads can be generated) is being maintained. The latter makes it possible to carry out relatively a large number of tests in a short time. Depending on the circumstances 4 to 8 tests a day.
Elaboration and interpretation of the test results are carried out with specially developed software according to the "unloading point method". In comparison with various static load testsperformed for inspection it shows that the accuracy of the therefor predicted collapse load capacity is highly decent.
APTS can mobilize the necessary equipment for the statnamic test and the implementation and formulation of the test guide. Naturally, the reporting and its interpretation will be taken care off.
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