Aspects of the performance of different materials in earthquakes

This paper discusses the general principles of the behaviour of construction materials when exposed to earthquakes. The construction materials considered are timber, concrete, steel, soils and elastometrics. Whereas timber is used essentially for residential buildings, concrete and steel take up different structural forms, making it convenient to deal with their performance in this way. In concrete, for example, mass concrete dams, reinforced concrete buildings and bridges are examined individually. Similarly, steel buildings are considered separately from steel bridges. In resisting earthquakes, construction materials are required to exhibit properties not employed in resisting static loads, the essentials of which are resistance to two components of horizontal force and vertical force acting together and changing direction many times each second, the vertical input increasing and decreasing the normal gravity loads. Material damping and lack of brittleness are required properties, as is the absence of liquefaction potential in non-cohesive foundations. In design there is a greater need to avoid discontinuities in both elevation and plan to prevent torsional effects caused by the two horizontal components. Although wind also produces horizontal loading, its precise effects are quite different. The selected examples are drawn from visits to earthquake sites, reports of the Earthquake Engineering Field Investigation Team, and the author's contacts around the world.