Limitations have to be determined for vibrations resulting from various construction techniques. The limits are determined such that possible damage may be avoided.
The possible danger of disturbance/settlement resulting from activities leading to vibrations needs to be evaluated. This also applies to possible damage to sensitive equipment on nearby property (e.g. computer installations, printing presses), as well as the possible inconvenience to neighbours. The limits apply to the maximum permissible peak particle velocity (given as mm/sec) which is determined based on the:
- ground conditions where the construction is located
- type of construction and the quality of building materials used
- distance from the source
- type of vibration (e.g. blasting, demolition, piling, tunnel boring machine or other tunnelling operation).
A further consideration is the issue of regenerated noise. Ground-borne (or regenerated) construction noise can be present on construction projects where vibration from activities such as rock breaking, road heading, rotary cutting, and rock drilling/sawing can be transmitted through the ground and into the habitable areas of nearby buildings. Ground-borne noise occurs when this vibration in the ground and/or building elements is regenerated as audible noise within areas of occupancy inside the building. It is typically heard as a low frequency ‘rumbling’.
Typical internal ground-borne noise goals for residential receivers are (Department of Environment and Climate Change NSW 2009):
- 40 dBA LAeq (15 minute) during the evening (6:00 pm to 10:00 pm)
- 35 dBA LAeq (15 minute) during the night time (10:00 pm to 7:00 am).
These goals are only applicable when ground-borne noise levels are higher than airborne noise levels.
Further details of vibration requirements are discussed in GRT Part 3 (Austroads 2018).