‘Honeycomb’ slows down Namma Metro, HDK sounds caution

‘Honeycomb’ slows down Namma Metro, HDK sounds caution

A Metro train moves slowly as work to fix pillar No. 155 is in progress near the Trinity Station in Bengaluru on Wednesday. DH Photo/Janardhan B K

Passengers travelling on the Purple Line of Namma Metro were slightly inconvenienced on Wednesday after a delay slowed down services near the Trinity Metro station, owing to ongoing work on a Metro pillar.

During a routine inspection, the Bengaluru Metro Rail Corporation (BMRCL) maintenance team had found a ‘honeycomb’ (coarse and rocky appearance on the outer foundation with a close resemblance to a honeycomb) on a concrete beam near the Trinity Station. Some speed restrictions were imposed on trains at this location, as repair work was being carried out by engineers. The trains ran 15 minutes late.

Chief Minister H D Kumaraswamy, from Belagavi, had initially directed the authorities to halt Metro services on the line where the problem was identified. Later, he said technical experts had okayed plying trains at slow speeds.

“Somewhere near Miller’s Road, one column has collapsed. This came to my notice two days ago itself. Yesterday (Tuesday), the experts did a check and said that it’s okay to run trains at slow speeds and that the problem can be rectified. Still, I’ve asked them to cross-check,” he told reporters in Belagavi.

Honeycomb in concrete is caused due to various factors. One is poor cement-to-water ratio, which can reduce the concrete’s workability.

“While regular inspections were carried out by our maintenance team, a honeycomb under the concrete beam was found, and soon the BMRCL engineers were alerted. The restoration work is in progress now,” said Yeshwanth Chavan, PRO of Bangalore Metro Rail Corporation Limited. He said the repair work will go on for three more days.

When DH visited the spot, a raised steel platform was erected, blocking a part of the road near the Metro station where engineers were engaged in their tests at the pillar. A concrete slab supported by the pillar was found slightly displaced from its original position and hence a metal jack has been placed next to the pillar to support the slider until the repair work is done.

“A more detailed inspection of concrete is required through non-destructive method to ensure it is strong,” said Chavan. He said the affected portion is very small and may not affect the overall safety of the structure as the tests are conducted with necessary precautions.

By Wednesday evening, a WhatsApp message was being circulated: “Metro pillar in MG road got twisted, better avoid the road and metro through that route.” However, the PRO clarified that the message was misleading and wrong. “It is clarified there is no twisting of any pillars. We have raised a steel platform to do corrective action. Tests are being conducted by the engineers and no harm is suspected from this,” he said.