Structural Retrofits Protect Unreinforced Masonry Buildings From Damage in Earthquakes

Unreinforced masonry buildings (URM) are more vulnerable to earthquake damage “than any other kind of construction”, according to a Federal Emergency Management Agency report.

In fact, the FEMA report “Unreinforced Masonry Buildings and Earthquakes: Developing Successful Risk Reduction Programs,” states, “More than any other kind of construction, [this type of building] can be singled out as being seismically vulnerable.”

Owners of URM buildings are responsible to ensure damage to their structures, as well as death and injury to tenants, employees and pedestrians is minimized. This can be accomplished by having an earthquake retrofit engineered and constructed by Optimum Seismic to enhance the structural safety of your historic or heritage building.

URM have masonry lacking reinforcement within. The masonry is made of earthen materials, such as stone, brick, hollow-concrete brick, clay tile or adobe. Many URM buildings also feature heavy timber columns and beams within the interior. Heavy and typically weak walls of these structures contribute to their instability during earthquakes, as they often lack horizontal force resistance. Additionally, many include parapets, chimneys or other heavy ornamentation. Overall, URM buildings provide very little or no ductility – the toughness, flexibility or energy absorption capacity – to withstand a significant earthquake.

Optimum Seismic’s team of structural engineers and construction experts have many years of experience in retrofitting URM style historic and heritage buildings to help prevent collapse and injury in earthquakes.

Each historic preservation project is unique and requires extensive knowledge of structural engineering, building codes, and city ordinances. Properly restoring these structures comes with unique challenges, not the least of which is limited access to original documentation and complications arising from the original construction techniques.

Despite the difficulties, protecting these extraordinary buildings with earthquake retrofits helps preserve the legacy and character of our cities and protects the community surrounding them. Earthquake retrofits of these buildings also provide financial and practical benefits for building owners and businesses operating within them. These benefits include:

• Reduced risk of personal injury and death
• Reduced risk of property damage
• Reduced risk of litigation and liability
• Reduced insurance costs
• Improves the value and marketability of the building

Unreinforced masonry buildings suffer from multiple structural weaknesses that become especially problematic during earthquakes. Built long before building codes addressed seismic s