ESC-30V is used to monitor the radial and tangential stresses in the shotcrete of tunnels, particularly where the New Austrian Tunnelling Method and underground works are being implemented. Measurement of radial and tangential stresses within shotcrete lining is a vital feature of this type of stress cell. The stress cell has a rectangular pressure pad which is constructed with two stainless steel plates, welded around the periphery. The pressure pad and the electron beam welded vibrating wire pressure sensor are connected together by a 6 mm Φ x 165 mm long stainless steel tube. The cavity inside the pressure sensor and the pressure pad is filled with de-aired fluid. A pinch tube ECS-30V or regroutable arrangement ESC-30V-R is provided to inflate the pressure pad after concrete around it has fully cured, to ensure proper contact between pressure pad and surrounding concrete.
|Range (MPa)||1.0, 2.0, 3.5, 5.0, 10.0, 20.0, 30.0, specify|
|Accuracy*||± 0.5 % fs standard | ± 0.1 % fs optional|
|Over range limit||150 % fs of range|
|Temperature limit||-20° to 80°C|
|Thermistor||YSI 44005 or equivalent|
|Pressure pad sizes l x b (mm)||100 x 200 | 150 x 250 | 200 x 300 | 300 x 300|
|Other sizes also available on request | *Calibrated accuracy of pressure sensor|