Analysis of the Behaviour of Buildings During Earthquakes
Earthquakes are vibrations of the earth’s surface caused by sudden movements of the earth’s crust which consists of a number of thick rock plates that float on the earth’s molten mantle. The plates drift on convection currents generated by hot spots deep within the earth, and deform as they move, owing to interlocking at plate boundaries. As a result, stress builds up and when the shear stress exceeds the strength of the rock, a rupture occurs along the fault line in the rock and energy is released in the form of seismic waves. The origin of the fracture is known as the focus of the earthquake (Fig. 5.1). Two kinds of body waves are propagated from the focus. The first is the compressional or P wave, which is propagated as an expanding sphere of disturbance. The second is the S wave which is characterized by shearing distortion without any volumetric change. The point on the surface directly above the focus is called the epicentre of the earthquake. When body waves strike the free surface, they give rise to two kinds of surface wave. The first are called Love waves, and consist of a horizontal motion of the surface transverse to the direction of propagation.
KeywordsClay Convection Ductility Gravel Summing
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- 5.1.Goodman L E, Rosenblueth E and Newmark N M, Aseismic design of firmly founded elastic structures, Transactions ASCE 1955; 120: 782–802.Google Scholar
- 5.3.NBC: National Building Code of Canada, National Research Council of Canada, Ottawa, Canada, 1985.Google Scholar
- 5.4.Seed H B, Ugas H and Lysmer J, Site dependent spectra for earthquake resistant design, Bulletin of the Seismological Society of America 1976; 66: 221–243.Google Scholar
- 5.6.Applied Technology Council, Tentative Provisions for the Development of Seismic Regulations for Buildings, ATC 3–06, National Bureau of Standards, SP 510, 1978.Google Scholar
- 5.8.Smith J W, Vibration of Structures: Application in Civil Engineering Design, Chapman and Hall, London/New York, 1988.Google Scholar
- 5.9.Clough R W and Johnston S B, Effect of stiffness degradation on earthquake ductility requirements, Proceedings of the Second Japan Earthquake Engineering Symposium, Tokyo, 1966, pp 227–232.Google Scholar
- 5.10.Takeda T, Sozen M A and Nielson N N, Reinforced concrete response to simulated earthquakes, Journal of Structural Division, ASCE 1970: 2557–2573.Google Scholar