A house destroyed by an earthquake.
Earthquake retrofitting is the process of making a building or similar structure more resistant to the stresses and forces that an earthquake or other seismic activity exerts on it. This can involve a number of different procedures, although it generally involves a better connection between a building and its foundation, support for paralyzed walls, improved resistance to lateral load, and other procedures designed to strengthen the structure. This work is usually done before a major seismic event to prevent damage to a structure, and is often done in areas with a history of earthquakes, such as California. Earthquake retrofitting can prevent costly or dangerous damage to a building and is typically done on older buildings.
Earthquake retrofitting is the process of strengthening structures so they can better withstand an earthquake.
Also known as seismic retrofitting, earthquake retrofitting is typically performed by multiple workers under the supervision of a general contractor or similar construction professional. As the name implies, this retrofitting is done on structures that have already been built, usually older buildings that may have been built long before modern safe building standards were established. This work can involve a number of different changes, generally based on the specific needs of individual buildings, although certain procedures are quite common during earthquake rehabilitation.
Homes can be modified and inspected to make sure they can withstand earthquake aftershocks.
The basic goal of earthquake retrofitting is to ensure that an older building is capable of handling the stresses and strains placed on it during a seismic event. Many older buildings were designed to simply stay upright and avoid a single pulling force, which is gravity, pulling them down. However, during an earthquake, forces that are horizontal to the ground can act on a building; this force is often referred to as lateral loading. Retrofitting a building attempts to ensure that these forces are not capable of causing excessive damage to the building.
One of the most common forms of retrofitting due to earthquakes is bolting a building to the building’s foundation. Many older structures will have poor connections between the bottom of the building and the concrete foundation below. Foundation bolting generally involves bolting the sill, the effective foundation of a building, to the foundation below it. During an earthquake, the bottom of a building usually begins to shake and move from side to side before the rest of the building. This means that without earthquake renovation, an old building could literally slide off its foundation.
Another common type of earthquake retrofit is stall wall support and reinforcement, often referred to as stall wall bracing. Defective walls are walls found in an area at the bottom of many buildings, often supporting a crawl space under the floorboards, which are found between the foundation and the main floor of the building. During an earthquake these walls can be damaged and this can cause a building to collapse or become uneven on its foundations. Crippled wall bracing creates supports that strengthen these walls and help ensure that a building does not shift during a seismic event.