A mechanical fault seems to be the cause of the collapse of an underconstruction bridge of the Delhi Metro here, the DMRC said on Sunday, as it ordered a technical inquiry into the mishap by a high-level committee.
The accident took place at Vikas Marg in Lakshmi Nagar area of east Delhi when workers were lifting concrete segments of the bridge using a "launcher".
"It was the 11th segment in the stretch which collapsed while being lifted...Prima facie, it appears that the some mechanical item of the launcher might have given way," DMRC spokesperson Anuj Dayal told reporters.
He said the launcher belonged to Afcons, the private firm which was executing the work on contract. The company has been working with the Metro for the last one year doing similar jobs.
Safety checks are made while the launcher moves from one pier to another and "probably" there were some problems regarding safety inspection by the contractor, Dayal said.
The DMRC has seized all records of Afcons and sealed its site inspection office. "We will go through the records to find out there was any lapse," Dayal said.
Afcons officials were not immediately available for comment.
Dayal said a three-member high-level technical committee will probe the incident and fix responsibility.
"The Chief Engineer (Design) of DMRC and a foreign consultant would be the members. We will ask the IIT Director to nominate an IIT structural engineering professor to the panel," he said.
DMRC said 22 such launchers were working all over Delhi at present for lifting concrete segments to elevated spans.
"We have stopped work on all the launchers and will carry out a full safety inspection over the next two-three days before restarting work," DMRC Director (Works) Mangu Singh said.
The officials said site supervision is the responsibility of the contractor. However, Dayal added, "We are not washing our hands off. Ultimately the responsibility is ours. The incident is unfortunate and a big shock to us."
Asked whether there is extra pressure on the contractors to meet deadlines in view of the 2010 Commonwealth Games, Singh said "the contractors are working according to their programme. There is no pressure to expedite".
He said the Metro may consider deploying additional traffic marshals to alert passers-by near its construction sites.