BOLT-Tester measures the waveform of impact force that obtained by tapping a bolt or nut with an accelerometer installed on the hammer. Soundness of a bolt or nut is evaluated by its reaction.
Soundness test of an anchor bolt, wheel bolt, bolt and nut on steel girder bridge.
When an anchor bolt is correctly installed, the bolt behaves elastically and back to original position after the impact by the hammer. The more a bolt is firmly installed, the more the impedance (modulus of elasticity) becomes large. On the other hand, in case the bolt is not firmly installed, modulus of elasticity becomes lower and measured waveform will be disturbed. Moreover, adhesion becomes more lower, the bolt moves and strikes concrete, and measured waveform becomes two peaks. BOLT-Tester evaluates soundness of an anchor bolts by analyzing the measured waveform.
Example of the waveform
Waveform of stable anchor bolt
Measured waveform becomes most likely symmetry. Shape of the waveform becomes slightly disturbed depending on the condition of target bolt, number of peak is only one.
Waveform of a bit deformed anchor bolt
Peak of the waveform becomes wider as a response from the bolt is delayed.
Waveform of loose anchor bolt
Peak of the waveform becomes two due to the delay in a response from the bolt.