Home Articles Seismically Defficient Structures: Engineering Lessons

Seismically Defficient Structures: Engineering Lessons

C.V.R.Murty, Umesh Dayal, Jaswant N. Arlekar, Sailendar K. Chaubey and Sudhir K. Jain

The performance of the structures in the Kachchh area serves as an excellent test of the efficacy of Indian building codes and construction practices

A powerful earthquake of magnitude 7.9 struck western Gujarat at 8:46 am on 26 January 2001; over 20,000 persons are reported dead and about 1.7 lakh persons injured. The quake caused widespread damage and destruction to both rural constructions and urban buildings and industrial facilities. This event is very significant from the point of view of earthquake disaster mitigation in India. While the five moderate earthquakes that struck India since 1988 consistently demonstrated the vulnerability of the rural constructions of India, this event pointed out that even some of the engineering structures built with the traditional wisdom of design and construction prevalent in this country, are vulnerable.

The earthquake provided numerous examples of geotechnical and structural failures. These include collapse of modern reinforced concrete (RC) frame buildings and damage to earthen dams, bridges and other industrial facilities. Detailed studies are required to investigate into the exact cause of failures. However, it seems that the general practice of design and constructions do not incorporate earthquake resistant features in them. Therefore, the performances of these seismically deficient structures offer important lessons for immediate corrections in the time ahead. Interestingly, the deficiencies now recorded after the 2001 Bhuj earthquake were already known and well documented after the past earthquakes across the world.

This photo presentation is a brief graphical summary of the salient structural and geotechnical damages recorded during a reconnaissance survey conducted by a team of 15 investigators (consisting of geologists, seismologists, geotechnical engineers, structural engineers and emergency managers) jointly headed by Professor Sudhir K. Jain of IIT Kanpur, and Dr. William Lettis of William Lettis & Associates, Inc, USA. The Earthquake Engineering Research Institute (EERI), USA, and the Department of Science and Technology (Government of India), New Delhi, supported the investigation to document the important lessons learnt from the earthquake.n

  • With several weeks gone by after the earthquake, as the people of Gujurat are trying to rebuild their life together brick by brick there is a severe shortage of trained structural engineers in the region who can assess the damages and suggest measures for repair/seismic retrofit of the damaged buildings. Initiatives, both short term and long term, are required to build capacity in the technical community to tide over this earthquake disaster as well as to develop preparedness for upcoming earthquakes in the country.

  • The Great Runn of Kutch, the Arabian Sea and the Little Runn of Kutch lock the affected area on its three sides causing large-scale liquefaction and embankment failures as it is near the sea level. 245 small and medium dams were damaged during the earthquake. The earthen embankments of the railroad and highways, the industrial warehouses and the control tower buildings at the port of Kandla suffered major damages owing to both structural inadequacies as well as liquefaction of the ground.

Photo Gallery

Common man learns: even RC frame buildings can break apart!!

Cracks along the crest and vertical settlement of the Suvi dam.

Pancake collapse of 4-storey L-shaped RC framed school building in Ahmedabad.

Collapse of ground storey of a two-storey RC frame building in Manfara village.

Common man learns: even RC frame buildings can break apart!!

Collapse of random rubble stone masonry constructions along a street in Morbi town.

Partally collapse pagoda at the palace at Morbi

A common site of destruction of the villages in the meizoseismal area

Collapse of upper storey of buildings at Gandhidham. It is suspected that this may have been caused by inadequate lap lengths in the column reinforcement.

A number of railway stations suffered extensive damages. Fortunately, at this location, no one was killed since at the time all the railway staff had gathered elsewhere for the Republic day flag hoisting ceremony.

Massive slope failure of the rail-road embankment near Navlakhi port resulting in fracture of rails, and damage to prestressed concrete sleepers and panroll clips.

This rail embankment at Vaka Nala of about 5 meters height suffered extensive damage. The rails were hanging by about 1.0 to 1.5 meters after the earthquake. Ground liquefaction was observed at the base of the embankment.
 
 

Failure of the upstream slope of the Fatehgadh dam

Cracks along the crest of the Tappar Dam

A number of old masonry arch bridges for Indian railways sustained extensive damage. This bridge is about 88 years old.

This pier at the RC bridge near Vondh was found to have a tilt. Considerable liquefaction was observed at the site.

Collapse of the temple pagodas made of large block stone masonry at Halvad near Ahmedabad

Insufficient connection between the RC elevator core and rest of the building lead to the underutilization of the lateral strength and stiffness of the elevator core

Massive cracks in the upstream embankment near the toe of the Fatehgadh dam

Damage to kerb of highway pavement due to lateral spreading of soil.

Unsymmetrical failure of stone masonry arch railway bridge.

 

Collapse of the random rubble masonry intake tower at the Tappar Dam.
 
Total collapse of a portion of a 10-storey residential building in Ahmedabad.

Collapse of one-half of the 14-storey RC frame residential apartment building in Ahmedabad; the collapsed portion had a swimming pool on the roof, unlike the other half that is standing.