Designing Buildings To Withstand Earthquakes

Japan and the United States are two of the world’s most technologically advanced countries. Geographically, they also have something in common: significant earthquake fault lines are found within their borders. They both have a problem of protecting people and infrastructure from earthquakes but they have responded in different ways.

The Use Of Base Isolators

A building shakes with the ground during an earthquake. If it shakes too much, this can cause structural damage to walls, beams, columns, and braces. Even if a building remains standing, damage to these structural elements means it is no longer safe.

Base isolators act like shock absorbers and reduce the amount of sway and tremor during an earthquake. They sit between the building and the ground and allow the building to slide back and forth. Buildings that use base isolation are more likely to survive a strong earthquake. The anchor bolts, beams, and braces remain undamaged and the building stays functional.

Japan’s Preparedness For Earthquakes

Large earthquakes have caused severe devastation in Japan in the past and this has led to a great demand for more robust buildings.

The engineering industry and government mandates have led to the building of stronger structures that can withstand earthquakes and be used as though nothing had occurred. Thousands of buildings in Japan have been fitted with devices that can absorb shock, reduce damage, and prevent collapse.

Consumers are willing to pay a premium for the latest earthquake safety technologies. One company has even developed inflatable airbags to use under wooden homes in event of an earthquake.

A Different Philosophy In the United States

In the United States, the philosophy is rather different. In a severe earthquake, the idea in the U.S. is to preserve lives, rather than buildings. Of course, the U.S. does have far fewer earthquakes than in Japan.

Rather than government mandated, resilient buildings are an individual choice. Many engineers believe buildings have a relatively slim chance of being hit by a large earthquake during their lifetime of about 50 years. Making buildings more resilient also costs money and people who already have to pay a high price for construction are unlikely to be happy if costs become even higher.

In the United States, new high rises are usually built around a reinforced concrete core, and use the highest quality nuts and bolts. In Japan, tall buildings are almost always built with steel. This is because Japanese engineers say reinforced concrete behaves unpredictability during an earthquake.

A notable exception in the U.S. is the design of Apple’s headquarters in Silicon Valley. The building is not attached to the ground. Stainless steel pucks found at the base of the support columns sit on top of huge steel saucers. When an earthquake hits and the ground shakes, the pucks slide across the saucers.

Cities such as San Francisco are considering implementing rules requiring buildings to be more rigid, like those in Japan. Earthquake-proof construction simply does not exist, but experts say buildings in the U.S. could be made more resilient without a drastic cost increase. Seismic safety advocates believe that Americans are missing out on the opportunity to save billions of dollars in reconstruction costs after a large earthquake strikes. Hopefully, the developers and city planners will be more proactive when it comes to future construction projects