Smriti Kak Ramachandran
NEW DELHI: The probe team set up by the Delhi Metro Rail Corporation (DMRC) has attributed the July 12 accident at Jamrudpur that claimed six lives to “deficiency in design” and “lack of adequate curing of concrete.”
Making public the findings on Tuesday, DMRC Managing Director E. Sreedharan pinned the blame on the design team, and held the incorrect advice of structural consultants as responsible for the accident.
“The report of the committee, comprising A.K. Nagpal of IIT Delhi, B.R. Bose of the Delhi College of Engineering, and Stephen Lowry of General Consultants, was examined by our Board of Directors and has been accepted in toto. The findings reveal a major deficiency in design of the cantilever arm. The second fault was that the concrete used did not have adequate strength, probably due to lack of adequate curing.” Explaining the fault in design, Mr. Sreedharan said: “The reinforcement steel was not provided at critical places. A cantilever must have reinforcement steel at critical places. At certain tension points it was not properly distributed.”
The committee concluded that the concrete was well compacted, that there was no visual evidence of voids or irregularities, and that the reinforcement spacing and lapping was generally in accordance with the design drawings.
However, based on tests carried out on cores taken from the pier and cantilever, it was found that the concrete failed to meet the strength criterion by a wide margin. The committee said the cement content was only marginally lower than required in the design mix, and the reinforcement steel was of the required quality. “The committee feels the lack of curing might be the reason for the low concrete strength.”
Blaming Tandon Consultants for misleading the DMRC about the cracks on pier 67, designed by Arch Consultancy Services, Mr. Sreedharan said these were “first noticed on April 1, and on April 3, Tandon Consultants were asked for advice. In their report submitted on April 15, they said the cracks could not be attributed to inadequacies in design or material. They said the cracks were due to the settlement of concrete and misled us into carrying on with civil works.”
Referring to action being taken by the DMRC against the erring officials and the design and structural consultants, he said: “We have decided to blacklist Arch Consultancy Service for five years, Tandon Consultants will be debarred for two years, and Gammon India, the contractor for the line, will be issued a show cause notice as to why they should not be blacklisted for two years.”
The DMRC has suspended deputy chief engineers V.P. Srivastava and Mukesh Thakur, who were responsible for the design and site supervision. Chief engineer (Design) Rajan Kataria will be served with a major penalty charge sheet. The Corporation has also decided to demobilise and replace the expatriate consultant of General Consultants, C. Mallonga, who was directly responsible for ensuring the quality of work.
The DMRC has begun rechecking all cantilever piers to assess the quality of work at the rest of Phase II constructions.
“There are 87 cantilever piers, of which 38 are along the airport line. They will be rechecked by Sirish Patel and Associates. Based on their advice, necessary action will be taken to ensure that all cantilever piers are safe,” Mr. Sreedharan said. Sirish Patel and Associates will examine the 18 cantilever piers that have been found with hairline cracks. “Each and every pier will now be examined minutely and meticulously. The DMRC will not rely entirely on its own design team; there will now be checking at two levels. First, independent consultants will check the design and then the DMRC design office will check them.”Related news: