Our customer wanted to measure the amount of rebound from pile-driving through a pier with a Sampling Moire Camera, as described below.
Pile-driving is the act of driving a pile into the round in order to support the load of a building, bridge, etc., on solid ground. The amount of rebound is the amount of return. It can be calculated by subtracting the amount of settlement when the pile comes into a stationary state from the maximum amount of settlement momentarily caused by a single impact at the time of pile-driving. The reason why a measurement of the amount of rebound is required is because, in pile and other driving work, the amount of rebound is necessary to make a judgment in relation to acceptable penetration. The traditional, conventional method of measuring the amount of rebound, a sheet of section paper is attached to the pile, and an operator directly pushes a writing tool against the pile to obtain a manual recording. This was considered dangerous and was not a reliable measurement method. We conducted the measurement of this amount of rebound using the Sampling Moire Camera.
This graph confirms that the pile reached the supporting layer of a solid foundation and is in a safe condition, while the vertical axis represents displacement (in millimeters), the horizontal axis is time (in hours).