Earthquakes are scary natural disasters. Even a small tremble will set the heart to racing, wondering if it will ever stop. Thoughts of “The Big One” comes to mind. In some areas, that big one is over nine points on the Richter scale. Most, however, think of the San Andreas Fault line that runs from near the U.S./Mexico border to San Francisco.
Building codes in earthquake country have changed dramatically, especially since the 1904 San Francisco quake. As steel became more available and a cheaper building material, it was incorporated into buildings. It took a while for folks to learn this, but it is actually one of the best building materials in an earthquake zone.
In the 1994 Northridge Earthquake, several freeway overpasses collapsed. This collapse resulted in a lot of problems, including the death of a highway patrol officer on his way to work. When they were rebuilt, they had steel reinforcements.
Steel is good for several other aspects of building safety in an earthquake zone. Like wood, steel can give in an earthquake. Not a lot, just enough to keep from breaking apart. Masonry and concrete, unless it is steel reinforced, can’t. Even then, parts of the building are likely to fail.
The other aspect of steel in earthquake-safe buildings is base isolation. Depending on where a home is built, it may be just stuck on top of a concrete slab. Safer buildings are anchored to the foundation with steel bolts. This helps to prevent the home from sliding off of the foundation during a temblor.
This sliding has red-tagged many homes, even when the homeowners thought that the building had been anchored. Those who survived the Northridge Quake relatively unscathed were instructed to check to see if anchor bolts were there. They were also strongly advised to add them if they were missing.
Larger buildings, such as hospitals, use base isolation. Some of them have had to be retrofitted with them, but they did prove their worth during that earthquake. They are a combination of bearings, springs and padded cylinders that the building more or less rides while the ground is shaking.
Active mass damping is another invention that is helping in earthquake situations. It was originally designed by the Japanese to help high rise buildings handle the sustained winds of super typhoons. However, that isn’t the only thing that shakes buildings on that island nation.
In September of 2011, an earthquake shook Tokyo. A steel constructed active mass damper had been installed in a building and it managed to reduce the intensity of the shaking. In part, this was due to a type of brakes installed. However, none of it would have worked without steel.
When choosing a building material, there are a lot of benefits to going with steel. It is fire-resistant, earthquake resistant and wind-resistant. Steel can keep a building on its foundation and prevent bridges from collapsing. It requires little upkeep and outlasts many other building materials.
