Rail Analysis India March 2018 Digital Magazine | Page 66

How to protect the residents of the buildings overlying metro tunnel
against train induced vibration & noise ??
Metro Projects
66 | Exclusive Interview
Train induced vibration from metro traffic transfers from soil through overlying building foundation to building
floors and then amplified by resonance within the buildings. Train induced vibration frequencies between 30
and 80 Hz are the primary cause of high vibration in buildings. These forces fluctuate in response to wheel and
rail roughness. As building floors usually have natural frequencies around 30 to 50Hz, train emission without
Mass Spring System will be able to excite the natural frequencies of the building into resonance which would
be then felt by human in addition to rumbling noise that radiates from walls and floors of the building.
Recommended criteria for Ground
Ground-borne-Vibration
Vibration (GBV) & Ground-borne-
Ground
Noise (GBN) as per RDSO Guideline for Noise & Vibration, September 2015 are
derived according to the Threshold values of human annoyance e.g; 72 VdB
(GB
(GBV)
V) and 35 dBA (GBN) for the residences and buildings.
buildings
In order to realise the above criteria, metro operators in India have chosen
Mass Spring System (MSS) so that metro tracks can safely run through highly
sensitive areas invol
involving
ving residential buildings, hospitals and structures of
historical Heritages.
Discrete bearing MSS system is the most accepted MSS worldwide due to its
replaceabilty within night maintenance hours, specially fo