Earthquake-resistant buildings

In most seismic regions, the adoption of construction techniques designed to reduce the risks associated with earthquakes appears to go back a long way. Excavations at the Taxila site in Pakistan, for example, revealed the need to reinforce foundations when the city was rebuilt after the earthquake of 25 AD. Similarly, in the Byzantine period, radical changes in construction methods were observed in several Syrian and Anatolian towns (reduction in house height, reinforcement with wooden frames, elimination of unreinforced brick walls). China and Japan also provide numerous examples of ancient buildings whose design was certainly influenced by consideration of seismic risk. The hypothesis that the very particular architecture of Inca monuments (walls made of irregular blocks fitted together with extreme care) corresponded to a concern for seismic protection has also been put forward.

Originally purely empirical, earthquake-resistant construction has gradually developed and taken its place among engineering techniques. It is multi-disciplinary in nature, calling on geologists, seismologists, architects, soil mechanics, structural engineers and calculators, whose collaboration is necessary for any major project in a seismic zone. Even if we remain within the realm of standard building design, the proper use of a seismic code by a structural engineer presupposes a sufficient grounding in seismology and an understanding of the particularities of seismic action (dynamic aspects, particularly random ones, and reasoning in terms of deformation rather than force).

The aim of this article is therefore to present an overview of earthquake-resistant construction, without limiting itself to considerations of structures and materials. It covers the essential elements of seismology, seismic design, calculation methods and the current state of regulations.

In the following, it is necessary to complete the article on the following two points:

• the significant changes since 1991 in the legislative and regulatory texts applicable in France for the prevention of seismic risk, as well as the technical documents on which they are based 4.3 ;

• the lessons learned from the major earthquakes of Northridge (California) on January 17, 1994...