Statnamic Load Test - Typical Equipment

Typical Equipment

The most common form of Statnamic rigs typically have testing capacities of 3 to 4MN. These devices are self-contained and may be transported using a single articulated lorry. Whilst on site they require the use of a mobile crane with a typical capacity of 70 tonne, with mobilisation in less than 2 hours. In addition to these typical capacities, devices have been produced which can apply maximum loads ranging from 0.3 to 60MN. To achieve greater loads the major components of the device including the piston, silencer-weight hanger and reaction mass must be scaled up in size.

The Statnamic weight packs usually consist of steel or concrete rings placed over the Statnamic silencer. As the device does not rely on gravity to apply loads as in static or drop weight testing it can be used vertically, horizontally and inclined to test raked piles. The ability to test horizontally has led to the method being used for lateral load testing of piles and simulation of ship impacts on mooring bodies (Middendorp, 2000). In order to improve the flexibility of the device and minimise transportation costs for offshore works a device has also been tested that can apply up to 14MN using water as a reaction mass. This is achieved in an over water pile tests by connected the Statnamic device to a vessel full of water below the water bodies surface (Middendorp, 2000), thus removing the need for heavy reaction weights.

The only significant difference between the smaller and larger testing devices is the method of catching the reaction mass. The catching method for larger tests uses gravel. This is achieved by placing the Statnamic device on the test pile and lowering the reaction mass onto its hanger. A large containing container is then placed around the assembly and filled with gravel. As the Statnamic weights move upwards the gravel moves to fill the void left and support the weights once movement has ceased. Due to the time required to place and remove the gravel after testing this method is reserved for tests above 16MN. Smaller rigs utilise a hydraulic catching mechanism that allows the mass to be caught within the frame of the device. This allows up to ten individual piles to be tested in a day or multiple cycles on a single pile at 15 minute intervals. Further description of the hydraulic catching mechanism is given by Middendorp (2000). The most recent development is the mounting of a 1MN Statnamic device on a 360° tracked excavator which allows rapid deployment (1 hour) and increased production.