Earth Pressure Cells • Concrete Stress Cells • Load Cells
 

Photo of 4800

 

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

Photo of 4810  

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

Photo of 4820
Photo of 4820 with Hydraulic Jack
 

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

Photo of 4830  

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

Photo of 4850  

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

Photo of 4900  

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.

Photo of 3000  

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.