Earthquake Building Safety

Earthquakes can cause severe damage to buildings with design flaws. Buildings constructed in earthquake zones that aren't properly engineered can collapse or suffer irreparable structural damage. Buildings in earthquake zones ranging in size from single family homes to skyscrapers can be built to withstand earthquakes.

Earthquake Straps

Earthquake straps are metal, cloth or plastic straps that prevent furniture, appliances, and electronics from tipping over during an earthquake. Earthquake straps attach different objects to walls, preventing them from tipping over and injuring people.

Home Foundation Retrofits

Many homes in earthquake zones built before 1980 do not meet modern earthquake safety requirements. Making your home more resistant to earthquakes involves retrofitting your home with bolts to attach the home to the foundation and straps to prevent the structure from sliding off of the foundation. In some foundations, plywood is added to increase the lateral strength of the place the walls meet the foundation.

Building Materials

The best building materials for earthquake zones are materials that will bend, and will not break or shatter. Wood bends more than masonry or concrete. If masonry is used, heavy concrete supports with adequate re-bar to allow for flexing during earthquakes is critical. Supports must have enough re-bar to prevent the concrete supports from shattering or collapsing.

Base Isolation

In new construction, the type of earthquake remediation will depend on the type of soil below the structure. In some cases, a technique like base isolation may be called for. There are a number of base isolation systems available. One technique places the structure on rubber mounts which allow the earth to move under the structure without moving the protected structure. The other technique involves using material that slides, such as a lead-bronze plate on a steel base, to allow the ground under the building to move while isolating movement of the building.

Dampers

In larger buildings, like Taipei 101 in Taiwan, a large damper is placed at the top of the building to counteract ground movement. This method uses a tuned mass, or a mass optimized for the size and weight of the building, that acts as a pendulum to stabilize the building as the ground moves underneath.

References

• Furniture Straps Disaster Preparedness
• About Earthquake Retrofit and Structural Earthquake Preparedness
• Base Isolation: Origins and Development

Resources

• Taipei 101's 730-Ton Tuned Mass Damper
• Hurricane, Flood, and Earthquake Resistant Building
• Concrete Homes: Tech Brief - Earthquakes