Ancient temple stitched back together
A 1,250-year-old temple has been saved from collapse using "granite stitching" in southern India.
The Kailasanathar Temple in the town of Uthiramerur is more than 1,250 years old, according to studies of its inscriptions.
Uthiramerur town, which is one of the oldest settlements in the state of Tamil Nadu, was highly developed according to inscriptions found in the town, which describes a society which held elections and had a government.
The temple dedicated to the god Shiva was built during the reign of Pallava King Dantivarman with additions made by later rulers.
"The centuries-old monument is made up of a brick super-structure and a granite substructure," explains Dr Sathyamurthy of the REACH Foundation and the prime mover behind this restoration and an archaeologist with four decades' experience.
Cracks of more than three feet in width had developed in the intricately constructed temple dome made of brick and lime plaster, which is around 80ft high.
"It was about to collapse completely and there were so many conservation problems because of the growth of thick vegetation on the Vimana or dome of the temple," Dr Sathyamurthy told the BBC Tamil Service.
While the upper part of the temple was in bad shape, the basement and plinth had other serious issues with cracks at more than 20 places in the granite stones according to the archaeologist.
Faced with serious technical problems the REACH team turned for advice to the Indian Institute of Technology, Madras (IIT-M) a premier engineering institute in India.
"The conservation team was faced with a problem as to whether the stone plinth can bear the weight of the entire super structure," Dr MS Mathews of the civil engineering department at IIT-M and a consultant to the Archaeological Survey of India, told the BBC.
When the monument was examined it was found that a few stones in the sub-structure were dislodged from their original position, and there were several cracks in the plinth due to stress, strain and shock says Anu Padma, who was involved in the conservation project as a research scholar.
"In Uthiramerur the options were limited. If the broken stones are to be removed and replaced, the restoration process would have become very complicated and could have further damaged the temple dome," Dr Mathews said.
Funding for the conservation project was another huge issue since governmental support for such projects were almost nil, according to the Conserver Heritage movement.
Conservationists also point out that while numerous monuments exist in India, the government preserves only 5% of them.
So the team at IIT-M decided that "granite stitching" would be the most simple, least invasive and the necessary method to restore the temple to its original glory, Dr Mathews said.
The site observation and inspection showed that the cracks in the granite stones were "non-progressive" and laboratory tests were conducted to assess the load-bearing capacity of stitched granite beams in comparison with the solid, uncracked granite beams.
"Test results proved that the stitching would bear the desired load," Ms Anu Padma said.
In the stone stitching technique, the cracks in the plinth are strengthened with stainless steel rods and an epoxy-based chemical anchor without disturbing the original structure.
Holes are drilled on both sides of a crack in a roughly 45 degree angle. They are then cleaned and the chemical anchor filled in, Ms Anu Padma further explains.
Stainless steel rods are then inserted and finished with rock powder to cover the conservation work and provide an aesthetically pleasing appearance.
"The inserted rod starts at one side of the crack and ends at the other side of the crack, holding both sides together. This is actually like stitching seen in cloth," she said.
According to Dr Mathews, the technique itself is very simple and not very expensive. But he says that when dealing with ancient monuments, it is important that care is taken over the materials used.
"High-grade stainless steel rods with a high percentage of chromium were used so that they didn't corrode for at least another five hundred years," he says.
Both Dr Sathyamurthy and Dr Mathews say that in India there are many temples and monuments in danger of total collapse or partial collapse and that these are causes for concern.
Dr Mathews says that further research in the laboratory in stone stitching and other reversible interventions is needed. This could allow the technique to be used to conserve other monuments in future.
With the basement safely secured, the team started conserving the super-structure, including the huge dome using a newly created lime plaster based on the old formula.
The conservation team now says that a weight of around 30,000 tonnes can safely rest on the basement and the plinth of granite rocks.