ENGINEERS SHOULD follow some of the principles of car design when faced with the challenge of designing earthquake-proof buildings, said a top earthquake specialist at the ICE's 7th Mallet-Milne Lecture at the ICE recently.
Professor of Seismology at the National University of Mexico Cinna Lomnitz said in his lecture - The road to earthquake safety - 'inexpensive safe structures exist today: they are called automobiles'.
Cars, he said, can withstand several g's of acceleration due to superior design and high levels of damping from shock absorbers.
Lomnitz noted that large amounts of reliable damping can be essential to suppress earthquake-induced resonant vibration in buildings, as was proven in the devastating 1985 earthquake in Mexico City where many tall buildings collapsed as they resonated with the long ground motions of the city's soft soils.
Lomnitz explained that 'trains' of earthquake waves can create a coupled mode of vibration which propagates in plane strains along the interfaces between the layers of soft saturated mud and layers of firm soil (akin to a rock thrown into a pond).
Lomnitz cited an example of a 120-storey building under construction in Mexico City using large fluid viscous shock absorbers which were originally developed in the Cold-War era for shock isolation of US nuclear submarines.
He said the pioneering spirit of the British earthquake scientists Robert Mallet (1818-1883) and John Milne (1850-1913) is continued today by some of Britain's leading universities, manufacturers and consultancies which are developing and implementing high-tech seismic solutions.
Lomnitz asserts that engineers, 'as the high priests of technology should be impatient with low-tech solutions to a high-tech problem, or with driving a high-tech car to their low-tech home.'
There is a saying in seismic engineering that earthquakes are not natural disasters, but man-made disasters caused by natural phenomena. Lomnitz said: 'We should strive for a future in which people will seek shelter in the next building in case of an earthquake.'
The biennially held lecture was organised by the Society for Earthquake and Civil Engineering Dynamics (SECED).
The lecture is commemorated in a book published by Balkema available through SECED at (0171) 665 2324.