‘Floating’ bricks, sandbox tech: Engineering skill behind 13th C Telangana temple’s UNESCO tag
It’s not just the exquisite craftsmanship that adorns the Kakatiya Rudreswara Temple, also known as the Ramappa temple, that makes it an architectural marvel.
Experts have been puzzled at the “engineering skill” behind the construction of the 13th-century temple, which has been intact for nearly 800 years.
Last week, the temple, tucked away at Palampet in the hinterlands of Telangana, was inscribed as a UNESCO World Heritage Site, the 39th in India. It is the first and only monument from Andhra Pradesh and Telangana to make it to the list.
Monuments that make it to the list, according to UNESCO, need to have an “outstanding universal value”.
They must meet at least one of the 10 selection criteria, some of which include representing a masterpiece of human creative genius and exhibiting an important interchange of human values over a span of time or within a cultural area of the world. According to Prof Pandu Ranga Rao of the Kakatiya Heritage Trust, what really sets the temple apart is its ‘floating bricks’ that were used to build the ‘Shikara’ roof of the temple.
Rao, a retired professor of the National Institute of Technology (NIT) in Warangal, said the bricks are so light that they can float on water. The density of the bricks is between 0.85 to 0.9 grams per cubic centimetre, whereas the density of water is 1 g/cc. Any usual brick has a density around 2.2 g/cc, he added.
The bricks were made of clay mixed with acacia wood, chaff, and myrobalan (a tree), making it sponge-like and allowing it to float on water. No other monument, at least in India, has the history of such floating bricks, Rao said, adding that they are one of the reasons for the temple’s longevity, as their weight or lack of it meant that there was little pressure on the foundation.
Another key feature that highlights the geotechnical aspects of the temple is its ‘sandbox technology’, which has helped it sustain despite being in a seismic zone, Rao said. The temple is known for its exquisite work and engineering | Photo: Rishika Sadam/ThePrintAccording to him, the entire temple has been built using this technology wherein a certain area is dug up, filled with sand, and then the structure is constructed on top of it. Structures built on these ‘sandboxes’ have a robust foundation as the seismic waves generated due to earthquakes are absorbed by the sand, Rao added. According to him, the temple survived earthquakes in the 17th and 18th centuries even as the houses around it collapsed. The temple’s pillars have sunk into the ground but despite this, the structure remains intact.
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