Seismic Building Retrofits

The goal of seismic building retrofits is public safety, first and foremost. Different levels of seismic retrofitting balance safety and economic considerations. Bridges are often reinforced to a point that will allow any vehicles on them to exit safely, though the bridge then will need extensive repair. Buildings can be retrofitted with the goal of letting people exit safely, even if the structure itself needs to be replaced. A higher level of retrofitting allows as little damage as possible, so that continued use of the building is possible. In a historic building, preservation of the original construction and materials is also important.

Different types of structures need different types of seismic retrofits. Buildings that are about ten stories high often need the most extensive retrofitting. They react to an earthquake in ways that are likely to cause maximum damage. Less tall buildings are stiffer and lighter, and move more freely in accordance with the ground motion. If they are constructed of poorly reinforced concrete or masonry, however, the damage can be significant. Buildings with more than ten stories usually have ductile steel frames, "ductile" indicating that the steel frame moves with the earthquake motion. This causes less damage to the structure.

What Are the Types of Seismic Building Retrofits?
Different methods of seismic retrofits can be applied to the individual needs of a particular structure. Isolation involves separating a building from its foundation and inserting rubber and metal isolating pads. Dampers convert earthquake motion to heat. Shock absorbers and slosh tanks are two other methods. Simple reinforcement is often effective in smaller buildings.

A careful seismic analysis followed by seismic retrofits can enhance safety and reduce the cost of repair after an earthquake. Saving lives and saving money can both be accomplished. For more information, contact The KPA Group at www.thekpagroup.com.