Structural audits on piers under construction for Delhi Metro Rail Corporation (DMRC) tracks have revealed 18 cracks on pillars. The company, however, on Monday said that there was "no need for panic".
The DMRC has begun to re-check all the piers of the metro's 190 km-long phase II, after the July 12 accident due to a crack killed six people. Independent consultant Shirish Patel and Associates were appointed to conduct the structural audits.
DMRC Managing Director E Sreedharan had asked metro engineers to inspect all the piers built on respective lines for any cracks.
"They found hairline cracks on eight piers of the Central Secretariat to Gurgaon corridor, two piers of the Noida corridor and eight piers of the Central Secretariat to Badarpur corridor. All appear to be superficial in nature," DMRC spokesperson Anuj Dayal said.
Dayal also informed that Sreedharan has asked the consultant to reassess the design of the 18 points in detail in addition to the overall checking of phase-II structures.
"DMRC will carry out further corrective action if required and take necessary remedial measures after Shirish Patel and Associates have examined these locations," Dayal added.
On July 12, an elevated stretch of the metro rail under construction in south Delhi collapsed with tonnes of concrete and steel, killing six and injuring 15 others.
Cracks noticed on pillars there were speculated by workers as the reason for the accident. However investigations so far have pointed to a design or construction material inefficiency.
While residents in Noida have expressed fear that DMRC is in a hurry to conduct trial runs on the nearly finished stretch, the company said that surface cracks in concrete structures are not uncommon and trials are likely to continue along with the investigation.
"There is no need for panic in the matter. In fact, Indian standard codes for design of reinforced concrete structures allows and permits tension cracks within limits," a DMRC statement said.
To further investigation, ultrasonic and rebound hammer testing will carried out to check the integrity and quality of the concrete. In addition,
"DMRC will get load testing done wherever considered necessary," Dayal said. "Similar testing was done during phase I of the construction also as a precautionary measure whenever required."