Strain Sensors installed on the St. Joseph Church

Strain sensor — This a strain sensor being welded to a #6 bar.

Strain sensor — This a strain sensor being welded to a #6 bar. (Michael South)

Welding equipment — We use special welding equipment that is specifically designed for strain sensors.

Welding equipment — We use special welding equipment that is specifically designed for strain sensors. (Michael South)

Welding gun — This welding gun has a very fine tip. The welds are done by making multiple spot welds along the sides of the sensor.

Welding gun — This welding gun has a very fine tip. The welds are done by making multiple spot welds along the sides of the sensor. (Michael South)

Completed Weld — The weld is now done, ready for testing.

Completed Weld — The weld is now done, ready for testing. (Michael South)

Prep for concrete — These sensors are going to be installed in a dome, then concrete sprayed around it. We have to change to a reinforced wire so that its not damaged during concrete spraying.

Prep for concrete — These sensors are going to be installed in a dome, then concrete sprayed around it. We have to change to a reinforced wire so that its not damaged during concrete spraying. (Michael South)

Node — This is showing the strain recorder. Its a wireless device that records the data from the strain sensor. We install an access box for this node, then when the dome construction is complete, we remove it.

Node — This is showing the strain recorder. Its a wireless device that records the data from the strain sensor. We install an access box for this node, then when the dome construction is complete, we remove it. (Michael South)

Testing sensor — Here we test the sensor before we go to install it.

Testing sensor — Here we test the sensor before we go to install it. (Michael South)

Live stream — These sensors are so sensitive, they can measure the strain you can create on the sensor by just pulling on both sides. In other words, it can measure how much you can stretch rebar with your bare hands.

Live stream — These sensors are so sensitive, they can measure the strain you can create on the sensor by just pulling on both sides. In other words, it can measure how much you can stretch rebar with your bare hands. (Michael South)

Ready for installation — Now the sensors are installed, we wrap them with a rubber glue patch. The rubber protects the sensor from the humidity and harsh conditions of shotcrete spraying.

Ready for installation — Now the sensors are installed, we wrap them with a rubber glue patch. The rubber protects the sensor from the humidity and harsh conditions of shotcrete spraying. (Michael South)