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Bi-directional static load testing

Bi-directional static load testing by James Fisher Testing Services is a truly innovative load testing technique that delivers rapid and accurate data.

The stability of a building or structure starts with a strong foundation and bi-directional static load tests (BDSLT) offer an essential calculation to certify that the design load can be supported by the piles.

Using a hydraulically driven, high capacity, sacrificial pressure cell, pre-installed into the test pile; the speed and accuracy of the testing method has made BDSLT an increasingly valued engineering tool.

Bi-directional static load test methodology

A hydraulic cell is attached to the reinforced steel cage to ensure its location and depth is located precisely. After the concrete reaches a minimum required strength, the test may be started.

Separation of the pile into two elements is induced by applying hydraulic pressure to the cell. As the load is applied the hydraulic cell begins working in two directions - upward against upper skin friction and downward against lower skin friction and base resistance.

Testing is typically performed until the ultimate capacity in either shear or end bearing is reached in order to determine the maximum pile capacity. The addition of strain gauges within the shaft can help to determine the distribution of the load throughout the shaft length.