Earthquake-proof buildings have several important features that prevent them from undergoing severe damage or endangering occupants during seismic disturbances. The average steel or concrete building has little protection against seismic forces, so if you live in an area that experiences earthquakes, look for professional building structures designed to keep standing. Here are several signs of earthquake-ready buildings:
- Strong joints. Joints undergo great stress during an earthquake. Anywhere your building uses joints, they should be focal points of strength, connections that are stronger than the beams themselves. There is a concept called “plastic hinges,” which does not mean that your hinges are made of plastic, but that beams are attached to the framework in such a way that the hinges absorb energy and easily shift vibrations without coming apart or breaking the beams. Steel beams and hinges work best for this arrangement, but high-quality, reinforced concrete can accomplish similar feats.
- Fixed, supported foundations. If your building uses columns or similar supports, they need to exhibit especially durable characteristics at the point where they are attached to foundations. Major supporters should be solidly grounded with a series of bolts attaching them to a large foundation. A grid of steel or steel rebar in concrete can create a similar result if the grid is large enough. When possible, stay away from typical sheet-metal or modular-steel buildings, which do not come with this vital foundational support.
- Innate flexibility. Rigid materials fare poorly during earthquakes, while ductile materials tend to do well in earthquake-proof buildings. This means that materials like steel and polymer concrete will do better than traditional concrete during seismic events. Metal is especially ductile, and able to transmit and dampen seismic forces rather than be torn apart by them. This makes metal buildings better in general than concrete, but strong foundations and joints are still very important.
- Light materials up top. When designing an earthquake-ready building, a rule of thumb is to make the building heavier at the bottom and lighter at the top. The roof should be as light as possible, moving from steel rebar and similar materials to light-gauge steel, aluminum, and other alternatives that use plenty of insulation but carry little weight. A roof slope is also necessary for proper earthquake protection – flat rooftops are more subject to damage.
- Strong floor and frame connections. Floors should be attached to the building framework with the strongest brackets and connections possible, especially when it comes to structures with more than one story. Light-gauge steel joists are generally better than timber joists to support frames during an earthquake. Of course, frames also need flexibility: Typical framework is attached to the foundation using pinned feet, but these pinned feet can wrench a building apart during an earthquake. It is better to start with steel ground beams carefully installed over padding, with load-resistance features in multiple directions.