Preparing your commercial buildings for the next earthquake isn’t just a theoretical exercise in California. We know earthquakes can hobble businesses, damage the economy and injure or kill people in our buildings. Even “newer” buildings constructed as late as the 1990s have elements known to fail during major earthquakes. This guide describes how seismic retrofitting can minimize these risks, and improve the earthquake preparedness California businesses urgently need.
Earthquake Hazards of Commercial Buildings
What happens to buildings during an earthquake? Some of the most common earthquake hazards for commercial buildings include:
- Collapsed walls, ceilings, floors and masonry
- Un-anchored building contents collapsing and falling
- Damage to electrical systems that can cause fire and shock hazards
- Dangerous gas and fuel line breaks
- Water and sewer line breaks
- Hazardous materials spills and leaks
In addition to localized building damage, disruptions and damage to critical municipal infrastructures such as utilities, bridges, roads, airports, and telecommunications can hamper efforts to rescue people and begin the recovery process. Even thriving businesses can go under in the aftermath. An entire town, city or community can suffer from being unprepared for an earthquake. If your business is prepared for an earthquake, however, your business might become a welcome anchor that can help the community and provide a needed morale and economic boost during recovery. This is why your business’ part in the “earthquake preparedness California” effort is so critical.
Commercial Building Designs and Structural Damage Caused by Earthquakes
It’s important to understand your building’s unique earthquake risks and to know that with earthquake retrofitting work, even older buildings can become earthquake resilient. If your business resides in any of these types of buildings, the following specific damage risks apply. You can enhance your earthquake preparedness against these specific risks by scheduling a consultation with Optimum Seismic for an earthquake risk assessment. Then you can start making the necessary retrofits and get prepared.
1. Tilt-Up Concrete Buildings: Walls Poorly Anchored to Floors and Roofs
Recent earthquakes have demonstrated that tilt-up concrete wall buildings are susceptible to collapse because the walls are poorly anchored to the floors and the roofs. When an earthquake strikes with the side-to-side (lateral) shaking, the combination of rigid walls and flexible roofs creates a significant collapse hazard that increases with the number of floors inside the building. Throughout Northern California and Southern California, these tilt-up concrete buildings are relatively common because they are fairly inexpensive to construct, and they can go up quickly. Many strip malls, light industrial facilities, warehouses, offices and other businesses call these buildings home. Seismic retrofit work involves strongly securing the walls, roofs and floors to minimize collapse hazards.
2. Unreinforced Masonry Buildings (URM): Weak Walls and Parapets
The majority of unreinforced masonry buildings (URM) were built long before today’s current earthquake building codes. These buildings are characterized by a lack of steel reinforcements and weak mortar that causes weak walls and parapets. These deficiencies can lead to a catastrophic collapse of walls and floors during an earthquake. After the Loma Prieta and Northridge earthquakes, many of these buildings suffered significant damage, yet were insufficiently repaired, and may not be able to withstand future earthquake damage. If you own or operate a business in an unreinforced masonry building, it’s crucial to have the seismic retrofit work done. This includes securing and anchoring walls, floors, and ceilings, as well as installing or applying overlays or bracing to the masonry walls to strengthen them.
3. Non-Ductile Concrete Buildings: Poorly Reinforced Walls and Columns
Many large office buildings are non-ductile concrete buildings that have insufficiently reinforced walls and columns that will break instead of bending during lateral shaking. This can cause large structures to collapse with deadly consequences for the people inside. Earthquake dangers can be mitigated by wrapping or “jacketing” concrete columns to strengthen them. Additional interior walls can also be added to help strengthen and improve the building’s ability to resist collapse. Each of these buildings requires a thorough seismic evaluation to determine the options for an earthquake retrofit.
4. Steel Frame Buildings: Fractures in Welds and Steel Elements
Many large, steel frame buildings built before the 1990s may already have fractures within their welds or riveted joints between their columns and beams from previous earthquakes. Although some of these buildings have survived previous earthquakes, it’s the undetected damage that now leaves them vulnerable to collapse in the next earthquake. These buildings require a full seismic evaluation, and can often be retrofitted by strengthening the beam-to-column connections with chevron bracing. We can also add a lateral system or dampers to bolster the steel moment frames.
5. Soft Story Multi-Unit Residential Buildings: Weak Open Front Stories
Many multi-family apartment buildings have insufficiently-reinforced front openings on the ground floor, often used for parking. Without reinforcement, collapse in these cases is almost inevitable. Fortunately, there are a number of specific soft story retrofit options that will significantly improve earthquake resilience in these buildings.
How Do Earthquakes Affect Your Building’s Businesses and Occupants?
When an earthquake strikes, how well you, your business, your employees and your customers’ fare depends largely on how well prepared you are for the event. If your buildings are not prepared, walls, floors and other large structural elements can collapse and kill people. Those left behind will face injury and economic hardship that can spread throughout the community. This is why it’s so important for businesses in California to take earthquake preparedness seriously today.
What Can Building Owners Do to Reduce Earthquake Risks?
The most important thing to do? Contact Optimum Seismic today at (833) 978-7664 to discuss earthquake retrofitting services for commercial, civil, industrial, and multi-unit residential buildings in California. We can assess your buildings’ earthquake resilience and help you enact the best earthquake retrofitting solutions. Schedule an appointment today for a free earthquake retrofit consultation with one of our structural engineering experts.