The Golden Gate Bridge

Developing Codes and Standards for Safer Structures


Innovative technology, such as base-isolation
devices pictured here at a museum under construction,
reduce accelerations transmitted in an earthquake.
In designing office towers, bridges, apartment blocks, single-family residences and other edifices to withstand an earthquake, Structural Engineers believe that the best offense is a good defense. In other words, the only way to beat an earthquake is to build and restore structures strong enough to withstand the forces of nature.

Today, Structural Engineers know with almost 100 percent certainty, based on the structure of various buildings, bridges and dams, how different types of structures will fare during any given size tremor. (See Studying Earthquakes.)

In small to moderate earthquakes, for example, buildings and bridges can survive virtually unscathed with the help of bracing, reinforced joints, or pads and rollers that allow the structure to move more freely when the ground starts to sway.

Consider the 1989 Loma Prieta quake which was a magnitude 6.9 temblor.

This quake was not considered by scientists or Structural Engineers to be The Big One but it made the upper floors of the Transamerica Pyramid building in downtown San Francisco 60 miles away from the epicenter sway more than a foot from side to side. Because of its earthquake-resistant construction (and, some may say, the luck of the draw), the building survived without major structural damage.