pressure strain gauge sensor

We build embedment gauges with a composite sealing system that handles long-term water immersion at typical civil engineering depths. The cable entry is epoxy-sealed and the body is stainless steel, so corrosion isn’t a fast problem. For pressures over 2 MPa, we add an extra O-ring seal. If you need it to work at 100 meters underwater, that’s custom but doable—just tell us the depth and we’ll spec the housing accordingly.

Arc-weldable gauges use a small flange that you weld around the gauge’s perimeter, which works on thick steel members in heavy civil structures. Spot-weldable ones are thinner and attach with a portable spot welder, better for sheet piles or lighter steel where you can’t use a big arc welder. Both types isolate the gauge from the welding heat through a standoff, so the sensor itself doesn’t get cooked. We include a mounting block to keep alignment during installation.

It depends on the expected strain. For concrete, strain rarely exceeds 2000 microstrain before cracking, so a ±3000 microstrain range is common. Steel can go higher, maybe ±5000 microstrain. If you’re monitoring a rock bolt, you might need ±2000 microstrain. We’ve got standard ranges, but can tweak the sensing element if your engineer gives us the maximum anticipated strain. Better to have a bit of headroom than to max out the sensor during proof testing.

The gauge factor and zero offset are set at the factory, and you shouldn’t need to recalibrate unless the cable is damaged or the installation altered the gauge’s state. What you do need is a good shunt calibration at the data logger end to check the whole measurement chain. We supply a shunt resistor value that simulates a known strain, so you can verify the system without loading the structure. If the readings drift later, it’s usually a moisture ingress or cable damage issue, not a sensor fault.

Yes. The spot-weldable gauges can be fixed to a radius as small as 300mm without affecting the gauge’s performance, as long as the curvature is smooth. For tighter curves, we bond the gauge to a thin curved shim first, then weld that shim to the surface. Embedment gauges are cast into concrete, so the surface shape doesn’t matter as much—they just need proper positioning before the pour. If you send us a drawing, we can advise on the best type.