Ground Vibration can be caused by construction, equipment or blasting, etc. Seismographs can be used to measure and record ground vibration. It is measured in terms of Peak Particle Velocity (PPV) and the units are mm/s. PPV refers to the movement within the ground of molecular particles and not surface movement. Ground vibration on a building or structure should be measured outside the structure and at ground level. The displacement value in mm refers to the movement of particles at the surface.
The mathematical formula for this is: PPV = 2πfa
Π = 3.142 f = frequency in (cycles per second) Hz a = displacement in mm
This formula is only true for sine waves.
The British Standards which provide guidance for measurement are: 1) BS:7385 Evaluation & Measurement for Vibration in Buildings
2) BS:5228-2:2009+A1:2014 Code of Practice for Noise & Vibration Control on Construction and Open Sites – Part 2: Vibration
3) BS:6472 Evaluation of Human Exposure to Vibration in Buildings
BS:7385 and BS:5228 concern levels of vibration which may cause damage, whereas BS:6472 provides a guide for nuisance levels.
There are a few reasons why it is important to measure vibration, including: