The new best way for testing pile load, improved method of static load tests and foundation load tests!
Bi-directional load test (or otherwise named Osterberg test or O-cell test) utilizes the hydraulically operated ‘Super Cell’ load cells, embedded within the concrete of the pile shaft for load and pile capacity testing. Before installing the foundation piles, soil investigation reports has to be done, to find the most optimal location for Super Cell installation.
The embedded Super Cells are specially designed with built-in Super-jacks. Hydraulic pressure is applied to the load cells by hydraulic pumps on the ground, through flexible hoses pre-installed along the reinforcement cages. The pressure in the load cell is measured by pressure gauges (pressure sensors); the displacements of the upper/lower parts of the pile shaft are measured by displacement transducers, which are connected to the load cell by embedded telltale rods.
When loaded, the Super Cell would expand and push the upper shaft upwards, and the lower shaft downwards. This sequence mobilizes the side resistance and base resistance of the upper and lower lengths of the pile. By analyzing the relativity between the movement and load force/time (S-lgt, s-lgQ curves, etc.) the carrying capacities of both upper and lower portions of the piles can be determined. The total carrying capacity of the pile can be found by adding up the modified side resistance of upward pile shaft, and the base resistance of downward pile shaft.
Bi-directional static load test advantages
Unlimited test load
Any desired load force may be applied to fully mobilize the piles for testing when Super Cells are installed. The test load exceeds traditional pile load tests, static load tests, and foundation load tests.
‘Super Cell’ load cells are unlike other static load tests, reaction systems are not required. Large quantities of girder beams and concrete blocks are not used to eliminate base toppling – an improved safety feature the Ougan Super Cell has.
Limited work area required
Next to existing buildings, under overpasses, highway median strips, and even offshore; much less space is required compared to traditional static load tests. Super Cells offer even more convenience for load test and pile capacity testing.
A considerable amount of time can be saved compared to static load tests with test blocks, since pile build up or strip down is not necessary. Promptly after installation, testing can be done.
Piles with deep cut-off levels
For basement piles, load test can be performed below ground, eliminating the pile extension to ground level.
Test for working piles
With advanced post-test grouting techniques, testing of working piles can also be done.