Shaken & stirred: walls of history

Pranesh Sarkar, TT: The temblor on Tuesday has inflicted more damage on Calcutta than the stronger one on April 25 that left Nepal devastated.

Engineers reported cracks on two iconic structures, Writers' Buildings and the Shahid Minar, after the 12.36pm earthquake that was followed by an aftershock at 1.06pm.

Officials of the public works department said a hairline crack that had appeared on a pillar of the Shahid Minar on April 25 was found to have "widened significantly" following Tuesday's jolt. A second crack was noticed on the outer surface of the monument that is part of the heritage zone in the heart of the city.

At Writers', cracks appeared on a pillar on the top floor of Block B, opposite the Calcutta Stock Exchange. A second crack was spotted on a wall of the same block.

The top floor used to house the office of the agriculture department before it was shifted to Jessop Building.

"The cracks in both the structures are signs of structural damage... As far as the Shahid Minar is concerned, immediate renovation would be taken up. At Writers', the entire block is to be demolished anyway as part of the ongoing renovation," a PWD engineer said.

Designed by Thomas Lyon in 1777, Writers' Buildings has added several blocks over the decades. According to senior government officials, Block B came up after Independence..

A crack on the outer surface of the Shahid Minar after the earthquake on Tuesday
afternoon. (Right) A damaged wall of Block B at Writers’ Buildings, which is to be
demolished as part of the renovation project  (Amit Datta)

The renovation of Writers' started in October 2013 and the state secretariat shifted to Nabanna, across the Hooghly. The project had been long overdue, especially in the light of warnings from engineers that Bengal's seat of power had turned into a tinderbox because of blocks being added to the main structure post-Independence.

The inspection report also mentioned that the superstructure had become vulnerable to earthquakes because of additional load being put on it in the form of extensions.

"It is now clear that the decision to renovate Writers' Buildings was the right one.... Had there been offices at Writers' now, the earthquake-inflicted damage to the structure might have been severe because more the number of offices, greater the load," an expert in structural safety said.

According to the renovation plan, finalised during a recent meeting chaired by home secretary Basudeb Banerjee, all blocks added to the structure post-1945 will be pulled down. "It means blocks A, B, C, D, E, F, G and CGA are to be demolished. This will help the structure shed the extra load put on it in the name of creating more office space," a senior government official said.

While nothing extra needs to be done at Writers' as of now, the PWD is worried about the hairline crack on a pillar of the Shahid Minar. "This pillar is crucial to the stability of the staircase within the 48-metre-tall structure. This is seen to be considerable structural damage and we have to renovate it at the earliest. A report has already been prepared and renovation will be taken up soon," the official said.

The monument, built in 1828 in memory of Major General Sir David Ochterlony, commander of the British East India Company, had undergone renovation in 2012. Entry into the Shahid Minar was restricted after a tourist jumped from the top in 1997. Since 2012, when the last round of renovation was carried out, nobody is allowed inside.

One of the keys to the interior of the structure is with the PWD and the other with Lalbazar, the city police headquarters.

"We visited the structure after Tuesday's tremor and found that the crack that had developed during the April 25 earthquake had grown wider. A fresh crack has appeared on the outer wall and that is cause for concern. We have sent a report to the government," said an engineer in the inspection team.

There had been rumours of damage to several vital installations in Calcutta after the earthquake last month, prompting the PWD to carry out a series of inspections.

At Nabanna, Tuesday's tremor did not cause any harm except causing panic as the 15-storey building swayed for several seconds.

Finance minister Amit Mitra and agriculture minister Purnendu Basu were among the first to exit their offices on the 12th and 3rd floors respectively.

Senior officials followed suit and stayed put in the courtyard for nearly 40 minutes after the earthquake, which measured 7.3 on the Richter scale at its epicentre in Nepal.