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Gainesville, FL, United States

Sinnreich J.,Loadtest , Inc.
Geotechnical Testing Journal | Year: 2012

Interpreting strain gage data from deep foundation (pile) axial load tests is usually assumed to be a simple calculation. The measured strain at any point in the test is multiplied by the computed Young's modulus E of the pile to obtain stress. The stress is then multiplied by the cross-sectional area A to derive the load carried by the pile at the elevation of the strain gage. However, if the product of A and E (the axial pile stiffness) is nonlinear, the load-strain path must be considered and an incremental approach taken in order to approximate the true load value. Concrete cast-in-place piles may develop transverse tensile cracks, either due to soil restraint during curing or as a result of applied tensile loads. As such cracks open and close, the resultant axial pile stiffness will change significantly and abruptly, and the assumption of a constant stiffness can lead to significant error when computing loads from strain gages. This paper presents the mathematical derivation of the incremental load-strain calculation and case histories to illustrate the method. Copyright © 2012 ASTM International.


Patent
Loadtest , Inc. | Date: 2013-05-20

In an embodiment, a hydraulic jack is provided having a first portion and a second portion. The first portion attached to a first section of a structure and the second portion attached to a second section of the structure. When a pressurized fluid is forced between the first portion and the second portion, a load is transferred to the first section and the second section by the pressure of the fluid on the first portion and the second portion. The first section and the second section are forced apart by the load, thus creating or enlarging at least one void in the structure. The pressurized fluid fills or partially fills one or more of the at least one void, thereby increasing the surface area effectively normal to the direction of the load in contact with the pressurized fluid.


An annular assembly, or ring cell, is provided for testing the load bearing capacity of piles. The ring cell walls of the annular assembly can be made of stamped material. The ring cell walls can be an outer ring wall and an inner ring wall. Alternately, the ring cell walls can have a U-type shape cross-section including an outer ring wall, an inner ring wall, and a top wall. Fluid can be provided to the annular assembly through fluid supply lines into an expansion zone. The expansion zone can be a space having a bladder for filling with fluid. In another embodiment, the expansion zone can be a space between a filler material capable of withstanding high pressure separated with a membrane. The pressure of the fluid in the expansion zone can be monitored during testing.


Patent
Loadtest , Inc. | Date: 2011-12-07

In an embodiment, a hydraulic jack is provided having a first portion and a second portion. The first portion attached to a first section of a structure and the second portion attached to a second section of the structure. When a pressurized fluid is forced between the first portion and the second portion, a load is transferred to the first section and the second section by the pressure of the fluid on the first portion and the second portion. The first section and the second section are forced apart by the load, thus creating or enlarging at least one void in the structure. The pressurized fluid fills or partially fills one or more of the at least one void, thereby increasing the surface area effectively normal to the direction of the load in contact with the pressurized fluid.


An annular assembly, or ring cell, is provided for testing the load bearing capacity of piles. The ring cell walls of the annular assembly can be made of stamped material. The ring cell walls can be an outer ring wall and an inner ring wall. Alternately, the ring cell walls can have a U-type shape cross-section including an outer ring wall, an inner ring wall, and a top wall. Fluid can be provided to the annular assembly through fluid supply lines into an expansion zone. The expansion zone can be a space having a bladder for filling with fluid. In another embodiment, the expansion zone can be a space between a filler material capable of withstanding high pressure separated with a membrane. The pressure of the fluid in the expansion zone can be monitored during testing.

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