The general safety and seismic vulnerability of Parliament House are suddenly subjects of anxious concern. Meira Kumar, the Speaker, observed that the building, with its cracks and absence of emergency measures, was ‘silently weeping’. Lok Sabha Secretary-General T.K. Visvanathan has said CPWD has asked the Central Building Research Institute in Roorkee to do a survey of the building. “We want to make sure that the 85-year-old building is able to withstand a major earthquake, given the fact that the national capital is quake-prone,” he is reported to have said. There is much talk that the government is planning to construct a new Parliament House.
> Download graphic: Circle of Strength
It took six years to construct the Lutyens-Baker designed Parliament House. Inaugurated by Lord Irwin on January 18, 1927 — originally known as Council House, and after independence as Sansad Bhavan — the building is majestically spread over six acres. Pink and red Dholpur sandstone were used in the construction. It has 144 pillars and the diameter of the building is 170 metres.
According to the Bureau of Indian Standards, the National Capital Region (NCR) lies in Seismic Zone IV. Two types of seismic experience are possible in Delhi. The first one is from quakes of magnitude less than 6.0 with epicentres within 70 km of Delhi. These do not cause major damage to engineered structures. An earthquake of magnitude around 5.75 occurred in Delhi on August 27, 1960. The epicentre was about 40 km from Delhi, near Gurgaon. It caused minor damage to buildings in the Delhi Cantonment area near Dhaula Kuan and other buildings.
The second is from a large magnitude earthquake in the Himalayas. If an earthquake of more than 7.5 magnitude occurs in Himachal, Uttarakhand or in J&K, the damage in the NCR would be of a different order. The distance of the Himalayan fault line from the NCR is about 270 to 350 km depending on location of the earthquake epicentre. At this distance, Rayleigh seismic waves are dangerous.
Within a 40 to 70 km radius of the epicentre, the damage from an earthquake in the Himalayas will be caused by shear waves (also known as S wave). These waves force on the foundations of structures, which could result in partial or full collapse of the building. As the depth of focus of a Himalayan earthquake would be of the order of 20 to 30 km, the effect of shear waves is negligible beyond 100 to 150 km from the epicentre.
Beyond this distance, a quake travels as seismic surface waves known as Rayleigh waves. These can adversely affect tall structures, typically more than 17 metres high, located at considerable distance from the epicentre. The effect of Rayleigh Waves was notably observed at Ahmedabad during the January 2001 earthquake (magnitude 8.0). In the city, at a distance of 320 km from the epicentre in Bhuj, only tall structures suffered heavily while two or three storey buildings escaped. Similar damage was also observed at Mexico City, located at distance of about 500 km from the epicentre, during a magnitude 8 earthquake in 1986. In the NCR, likely damage from a large magnitude earthquake in the Himalayas would be due to Rayleigh waves.
S waves cause damage by creating stress on sharp corners. Structures without sharp corners usually suffer less or no damage because the stress gets distributed almost evenly. This specific principle of even distribution of seismic stress has been effectively used in past constructions. These constructions have been standing for the last few centuries and have withstood the agony of severe seismic shaking. Kamakhay Mandir in Guwahati built in 1565 A.D. lies in the highest seismic zone, V. During the last 447 years, it has withstood three major earthquakes of magnitude 8.0 or more. The temple is still intact. There are no marks of any historical seismic damage the temple’s circular structure and the dome-type upper section.
Another such example is in Kangra, Himachal Pradesh, where the Bajura Mahadev Mandir, said to be 1,100 years old, is still standing, despite at least six or seven earthquakes of magnitude more than 7.5. This temple is not exactly circular. But it has four heavy flanges projecting in four directions, which gives it the character of a circular construction. There are reports that during the April 1905 Kangra earthquake (magnitude 8.25) several houses collapsed but the Bajura Mahadev Mandir did not suffer any damage.
Some historical records mention that the design of Sansad Bhavan is based on the design of a temple at Mitwali (Mitaoli) in the Morena district of Madhya Pradesh. This temple is known as Chausat Yogini temple, the word chausat referring to the 64 temples within the big circular temple. The temple was constructed in the 8th century A.D. It lies in Seismic Zone III. It can thus be seen that circular cross section constructions are standing in good condition at Mitwali (Zone III) for 1300 years, Manali (Zone V) for 1100 years and. Guwahati (Zone V) for 447 years,
Additions, alterations, modifications, and periodic repairs are natural in any old structure. The Capitol and White House buildings in the U.S are almost 200 years old. Without any major external change, these buildings have got by very well with just proper maintenance. The stadium of the University of California in Berkeley was built in 1923, and is located in the highest seismic zone in California. It has required major repairs due to ageing. Pulling it down was rejected as it was recorded in the National Historic Register. It has undergone total strengthening and now, it is claimed that it can withstand a major earthquake.
Advances in engineering and technology could be effectively used for the preservation, protection and conservation of Parliament House. Considering its height and circular design, the effect of an earthquake in the vicinity of Delhi or a large magnitude earthquake in North-west Himalayan region would be nil or minimum. The earthquake bogey must not be raised to justify any plans to build a new house for Parliament.
(Arun Bapat is a research seismologist. E-mail: arun_bapat@vsnl.com)
