The pride of SoBo, the Chhatrapati Shivaji Maharaj Terminus (CSMT), built in 1878, is expected to have domes restored. Repair work on the architectural element closest to the station will begin after Diwali. Central Railway officials said the prestigious heritage restoration project, with an estimated cost of Rs 50 crore, was nearing completion and only the domes remained.
The conical domes, according to experts, have developed cracks due to the aging of the stones. They started to flee a few years ago and the problem has only worsened in recent monsoons. An attempt was made to seal the seams of the outer surfaces of the stone masonry a few years ago by the Central Railway (CR) but this did not offer much relief. Current restoration work will be undertaken under the direction of renowned conservation architect and structural engineer Chetan Raikar.
Raikar said on Wednesday that these neatly cut stone features started showing material cracks a few years ago. This, he said, allowed rainwater to enter the structure. âIt would be interesting to note that these cracks are found in individual stones and do not extend beyond a single piece of stone in a single location,â Raikar said, adding that they are therefore classified as a geological failure of the stone, which is related to age. and is due to inclusions at the time of stone formation.
Raikar said the restoration work requires the stone to be sewn together using non-corrosive stainless steel pins. He said the gaps would be grouted using a lime mixture to prevent rainwater from entering the structure. âThese two engineering conservation techniques, when adopted, will collectively offer a long-term solution to strengthening this heritage structure,â he said.
A CR official said that more than 140 years ago, stones were the only material used for construction. While the central dome of the CSMT supports the Statue of Progress which is approximately 7.74m high and weighs approximately five tons, the diameter of the central main dome is 12m.
In 2019, a CR drone investigation found that the cracks existed despite the repair work. It was therefore decided to carry out radar tests from inside the dome. It is a modern non-destructive testing technique used by engineers to assess heritage structures. It works on the principle of sending electromagnetic waves through the material to be tested.
A CR official said the radar test indicated that the stones developed structural cracks, which are one of the main causes of the leak. Radar tests also confirmed that the thickness of the central dome varies from around 250mm to around 500mm.
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Posted on: Wednesday November 03, 2021 10:26 PM IST