The Kolkata Municipal Corporation (KMC) on Saturday formed an inquiry committee to probe the collapse of the Garden Reach building.
Its mandate is to determine the load-bearing capacity of the soil on which the building came up, the quality of materials used and the involvement or negligence of officials of the KMC.
The eight-member committee will also find out the ownership of the plot and its nature — whether it was a water body or land where construction can be allowed.
Many local residents had alleged that the plot where the building came up was a water body that was filled up.
In its first meeting on Saturday, the committee discussed the need to appoint someone from an engineering college to help in the probe.
“We have thought about involving Jadavpur University in our probe. We do not have a laboratory to analyse the quality of materials used or test the soil’s load-bearing capacity. Teaching institutions will have such laboratories,” said an official of the KMC.
No one from the KMC’s building department has been included in the team for the sake of fairness, though an engineer heading another department who had worked in the building department for many years is part of the team.
Sources told The Telegraph that samples of soil, concrete and reinforcements have to be collected from the site of collapse and analysed to determine their quality.
The load-bearing capacity of the soil determines the height of a building that can come up on the plot of land.
“It has to be seen whether the soil had the capacity to hold the load of a five-storeyed structure. Columns and beams hold together a building by transferring the load down to the soil,” said an engineer.
Before issuing permits for the construction of a building, the KMC, or any government body granting the permission, checks the soil test report.
“This building was illegal but that was not the reason why it collapsed. There are many illegal buildings in the city that are still standing. The collapse might be because the foundation was not strong, or the soil did not have the capacity to bear the load of a five-storeyed structure or very poor quality of the materials were used,” said an official.
Some KMC officials who had visited the collapse site said iron rods used for reinforcements were thinner than what was required for a five-storeyed structure.
Determining the nature of the plot — water body or land — is also an important part of the probe.
KMC officials said an aerial survey of Kolkata was conducted by the National Remote Sensing Agency in 2003. The map of this aerial survey is available with the KMC and it will show whether the plot was originally a water body or not.
The land and land reforms department of the state government will also be asked to provide information about the details of this plot that are available with them.
Death toll rises
The death toll in the Garden Reach collapse went up to 12 with Mariam Bibi, 85, succumbing to her injuries at SSKM Hospital on Saturday night. Doctors said she had been battling multiple injuries.
