Model 4800
Earth Pressure Cell
The Model 4800 Earth Pressure Cells are designed to measure
total pressure in earth fills and embankments. All cells consist of
two circular stainless steel plates welded together around their periphery
and spaced apart by a narrow cavity filled with de-aired oil. Changing
earth pressure squeezes the two plates together causing a corresponding
increase of fluid pressure inside the cell. The vibrating wire pressure
transducer converts this pressure into an electrical signal which is
transmitted as a frequency via cable to the readout location.*
| Specifications | |
| Standard Ranges | 0.35, 0.7, 1.7, 3.5, 5 MPa |
| Over Range Capacity | 150% F.S. (maximum) |
| Sensitivity | 0.025% F.S. |
| Accuracy¹ | ±0.1% F.S. |
| Temperature Range | –20°C to +80°C |
| Height x Diameter² | 6 x 230 mm |
| ¹Calibrated accuracy of the pressure sensor. ²Other sizes available on request |
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Model 4810
“Fat Back” Pressure Cell
The Model 4810 “Fat Back” Pressure Cell is
intended to measure contact earth pressures on the surface of concrete
or steel structures. The cell has an extra thick backplate to minimize
any point loading effects. ‘Ears’ on the cell assist in holding
the cell to concrete forms or to retaining walls during installation.*
| Specifications | |
| Standard Ranges | 0.35, 0.7, 1.7, 3.5, 5 MPa |
| Over Range Capacity | 150% F.S. (maximum) |
| Sensitivity | 0.025% F.S. |
| Accuracy¹ | ±0.1% F.S. |
| Temperature Range | –20°C to +80°C |
| Height x Diameter² | 12 x 230 mm |
| ¹Calibrated accuracy of the pressure sensor. ²Other sizes available on request |
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Model 4820
Jackout Pressure Cell
The Model 4820 Jackout Pressure Cells are used
to measure earth pressures on slurry walls. They are designed to fit
inside a plate which is pressed against the side of a slurry wall excavation
using a hydraulic jack arrangement. This method of installation ensures that
the jack out cell is located with its sensitive face in contact with
the adjacent soil. (Photo at left shows the Jackout Pressure Cell separately,
as removed from the assembly. Photo at lower left
shows Jackout Pressure
Cell Hydraulic Jack Assembly (with VW Piezometer installed).*
| Specifications | |
| Standard Ranges | 0.35, 0.7, 1.7, 3.5, 5 MPa |
| Over Range Capacity | 150% F.S. (maximum) |
| Sensitivity | 0.025% F.S. |
| Accuracy | ±0.1% F.S. |
| Temperature Range | –20°C to +80°C |
| Height x Diameter¹ | 12 x 150 mm |
| ²Other sizes available on request | |
Model 4830
Push-In Pressure Cell
The Model 4830 Push-In Pressure Cell is designed
to be pushed in place for the measurement of total pressures in soils
and earth fills. Where effective stress is required, the cell is fitted
with an integral piezometer. A thread is provided on the end of the
cell to allow for installation using lengths of pipe or drill rods.*
| Specifications | |
| Standard Ranges | 0.35, 0.7, 1.7, 3.5, 5 MPa |
| Over Range Capacity | 150% F.S. (maximum) |
| Sensitivity | 0.025% F.S. |
| Accuracy | ±0.1% F.S. |
| Temperature Range | –20°C to +80°C |
| Length x Diameter¹ | 600 x 50 mm |
| ¹Other sizes available on request | |
Model 4850
Concrete Stress Cell (NATM Style)
The Model 4850 NATM Style Concrete Stress Cells
are designed for the measurement of tangential (4850-1) and radial (4850-2)
stresses in shotcrete tunnel linings. The cells consist of two rectangular
steel plates welded together around the periphery with a de-aired fluid
occupying the space between the plates. A short tube connects the cell
to a vibrating wire pressure transducer. For environmental protection,
no mercury is used in these cells. A prestressing tube is provided for
expanding the cell after the concrete has cured. Cells of this type
are also used for measurements of stress in mass concrete.
| Specifications | 4850-1 | 4850-2 |
| Standard Ranges¹ | 7, 20 MPa |
2, 3, 5 MPa |
| Over Range Capacity | 200% F.S. | 200% F.S. |
| Sensitivity | ±0.025% F.S. | ±0.025% F.S. |
| Accuracy | ±0.1% F.S. | ±0.1% F.S. |
| Temperature Range | –20°C to +80°C | –20°C to +80°C |
| L x W x H² | 100 x 200 x 6 mm | 150 x 250 x 6 mm |
| ¹Other pressure ranges available on request. ² Other sizes available on request |
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Model 4900
Load Cell
The Model 4900 Vibrating Wire Load Cell consists of a cylinder
of high-strength, heat treated steel with 3, 4 or 6 vibrating wire strain
gages located around the circumference of the cell. Loads applied to
the cell are measured by the vibrating wire strain gages. The effects
of uneven and eccentric loading are minimized by averaging the output
of all 3, 4 or 6 individual readings.
| Specifications | |
| Rated Capacities¹ | 1 to 10,000 KN |
| Over Range Capacity | 150% F.S. |
| Approximate Sensitivity | 0.025% F.S. |
| Accuracy | ±0.25% F.S. to ±0.5% F.S. |
| Temperature Range | –20°C to +80°C |
| Internal Diameters¹ | solid, 25, 50, 75, 100, 125, 150, 200, 250 mm |
| ¹Other capacities and diameters available on request. | |
Model 3000
Load Cell
The Model 3000 Load Cell is made from an annulus of high-strength
steel or aluminum on which several electrical resistance strain gages
are located. The load cell is designed primarily for use on tiebacks
and rockbolts although they may be used during pile load tests and for
monitoring loads in crosslot struts and tunnel supports, etc. In most
cases, the load cells are used in conjunction with a hydraulic jack
and bearing plates.
| Specifications | |
| Rated Capacities¹ | 100, 150, 200, 300, 500, 600, 1000, 1500, 2000 kips |
| Over-Range Capacity | 200% F.S. for aluminum 300% - 400% for steel |
| Linearity | 0.5% F.S.R. |
| Accuracy | 0.5% F.S.R. 0.1% with polynomial expression |
| Input Resistance | 350 or 700 ohms |
| Temperature Range | –20°C to +80°C |
| Internal Diameters¹ | solid, 25, 50, 75, 100, 125, 150, 200, 250 mm |
| ¹Other capacities and diameters available on request. | |