Humans are sensitive to vibration and there is a wide range of sensitivity to vibration, with some people able to feel low levels of vibration.
Contributing factors to the human perception of vibration include the length of time of the vibration event, the vibration duration, the frequency spectrum of vibration, the number of occurrences per day, the time they occur and the magnitude.
The threshold of human perception to vibration is low (vibration level of 0.3 mm/s or lower). It should also be noted vibration levels as low as 1mm/s can result in movement of small objects, like ornaments, hanging photographs, trinkets etc. on hard surfaces and this can often exacerbate how vibration levels are perceived. The vibration levels which would be required to cause building damage are much higher than this.
When vibration effects occur, and we feel vibration or hear windows rattle, attention can be drawn to existing cracks in walls and construction works can be thought to be the cause.
The vibration standards we use to manage construction vibration are conservative in their proposed limits to ensure vibration levels do not go above ‘safe’ vibration levels (typically set at 5mm/s) for the control of building cosmetic damage. It is impracticable to devise a set of vibration guidelines that account for the condition of a property, the mode of construction, the workmanship, the type of construction, age, number of floors etc. Rather, the standards propose a lower permissible level of vibration which considers each of these factors, effectively introducing a large factor of safety for most properties, and importantly, an acceptable value for all properties, irrespective of their condition.
Vibration effects from high vibration generating activities such as piling, rock breaking and compaction have the potential to exceed the ‘safe’ vibration levels if not appropriately assessed and managed. To ensure activities are appropriately managed, the Transport Agency require projects to implement a Construction Noise and Vibration Management Plan. For further information go to State highway construction and maintenance noise and vibration guide.