The Chennai Corporation has requested Chennai Metro Rail Limited (CMRL) to install additional equipment to measure the impact of vibrations on heritage buildings.
According to sources in the Corporation, the reluctance of CMRL to share data pertaining to building settlement, ground settlement, tilt, vibration measurement and water level has been allegedly due to the failure of the contractor to “install equipment to measure vibration on the heritage building.”
CMRL has been carrying out collection of such data through their agency. The structural condition of Ripon Buildings and Victoria Public Hall, for instance, were assessed. However, officials say that even after several months of collection of the data, CMRL has not shared it with the Corporation’s engineers in charge of renovation and maintenance of Ripon Buildings.
“We have requested CMRL to install an accelerometer along the height of the heritage building,” said an official of the Corporation. The equipment will be used to generate data on vibrations caused to heritage buildings, such as Ripon Buildings, and for proper monitoring of structural vibrations caused during construction and operation of the metro rail.
The manual of environmental management arrangements of CMRL reads: “During the construction period, archaeological or historic resources may potentially be affected by direct or indirect construction activity. Prior to the initiation of construction, general consultant intends to review a resource protection plan for historic structures. The plan will identify sensitive resources as well as specify monitoring requirements. These requirements may include ground vibration monitoring and recording any components inadvertently subjected to impact. In the event the project affects a previously unidentified historic property, work in the area shall cease until actions that will take into account the effect of the undertaking on the property can be determined.”
“We are cautious as heritage buildings are delicate structures. We do not have Indian standard codes for such data. However, the upper limit of peak particle velocity of 5 mm per second seems to be acceptable for such heritage buildings,” said Arun Menon, general heritage consultant for Ripon Buildings from IIT-Madras.