Earthquake-proof structures

Particularly the horizontal forces released during earthquakes endanger the stability of structures.

The use of steel beams in construction work in earthquake hazard regions has distinct ad­vantages. However, complete protection from earthquakes does not exist. Nevertheless, suitable construction measures help to considerably reduce the danger of a structure col­lapsing, even in the event of strong earthquakes. There are no worldwide standards, but at least for Europe the requirements on the design of earthquake-resistant structures have been summarised (EUROCODE 8). Safety standards have been defined for high-rise build­ings, bridges, pipelines, towers and stacks.

In regions threatened by earthquakes, steel beams should be used in construction work in­stead of stone or concrete. Steel has a certain elasticity and therefore even compensates clearly perceptible earth movements. Moreover, the design of structures must be symmetri­cal and not compartmentalised or staggered, and all floors must have a uniform resistance. The use of continuous steel beams and cross-struts in each, not every second floor, is ad­vantageous.

In regions at particular risk, subsurface parts of buildings are ideally protected from earth movements by soft rubber blocks or springs. If such insulation is not used, the foundation of the structure would be made to vibrate via the foundation by an earthquake. Also a steel plate supported on springs in the top floor of a high-rise building reduces structural vibration, as vibration is likewise induced in the plate by the earthquake, producing a countermove­ment. A structure of this kind is also referred to as a vibration damper.

If building regulations are not observed in order to save costs, or do not even exist, com­paratively weak earthquakes can cause major damage and fatalities. The Mw 7.1 quake on Haiti on January 12, 2010 was violent, but suitable construction measures could presumably have minimised the number of deaths (300,000), as collapsing buildings in particular were responsible for this disaster.

text, eskp.de CC BY;photographs and graphics, if there are no conflicts with other licences as well: eskp.de CC BY

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