The scales are checked regularly to examine the impact of work on structures.
Mumbai: As a part of safety precaution, the Mumbai Metro Rail Corporation (MMRC) has installed scales in the heritage buildings to monitor the widening of cracks or existing gaps. These scales are checked regularly to get an update about the impact of work on such structures. In the DN Road stretch alone, 35-40 scales have been placed. Apart from that, vibration machines are set to study the frequency of vibrations. The MMRC has already conducted a structural survey of all the heritage buildings. The implementing authority said it is well aware of the challenges and has taken all required measures to deal with old and weak buildings.
“We have installed crack meters in every columns and walls where cracks were noticed by our team. This will be monitored every day, if any day we find that the crack has widened then, our appointed geologist will suggest the necessary precaution,” said an MMRC official who is in-charge of D.N road stretch. Piling work is currently being undertaken at this stretch. Along with crack meters, vibration gauging machines are also installed in front of such structures to study the level of vibrations. “Permissible limit for vibration is 5mm per second, but the current work is not exceeding the 2mm mark,” said the official.
He added that micro level survey and testing would be done when the tunnelling process starts. The MMRC has imported a Tunnel Boring Machine (TBM) from China especially to carry out the tunnelling work for this route.