Earthquake Risks of 5 Commercial Building Types
Earthquakes don’t just shake the ground—they test the strength of every structure built upon it. For many types of commercial buildings, especially those constructed before modern safety codes, seismic events reveal dangerous vulnerabilities that could put lives and investments at risk.
From concrete tilt-ups to soft-story apartments with open ground floors, each type of commercial building faces unique challenges when it comes to withstanding seismic forces. Knowing the risks and the solutions available is crucial for property owners who want to protect their assets and ensure occupant safety.
This guide examines high-risk commercial buildings, their vulnerabilities during earthquakes, and the seismic retrofits that can make them safer, stronger, and code-compliant.
Commercial Building Types and Their Vulnerabilities
Every building tells a story—and for some, that story includes risks hidden in their design. Let’s examine the most common types of commercial buildings and the seismic challenges they face.
1. Concrete Tilt-Up Buildings
Concrete tilt-ups are staples of industrial construction. They are created by pouring walls on-site and tilting them into position. While efficient and widely used, older designs often suffer from weak roof-to-wall connections and poor continuity ties.
When earthquakes strike, the heavy concrete walls can pull away from the roof, creating significant collapse hazards. Evidence from past seismic events highlights the dangers of these structures, which are prone to severe damage or failure.
Retrofitting, including reinforcing connections and adding structural details, is essential to improving their earthquake performance.
2. Soft-Story Buildings
Soft-story buildings are defined by open ground floors that lack the rigidity of the upper levels. These spaces are often used for tuck-under parking or retail, making them common in multi-family apartments and shopping centers.
While the design allows for practical use of space, the openness of the ground floor leaves the building vulnerable to collapse during earthquakes.
Retrofitting solutions like adding shear walls, braces, or moment frames can significantly strengthen the ground floor and enhance the building’s overall stability.
3. Non-Ductile Concrete Buildings
Non-ductile concrete buildings are rigid by design, with limited flexibility—or ductility—to absorb seismic forces.
This rigidity puts them at high risk of cracking or collapsing during an earthquake. Common examples include older parking garages, office buildings, and schools.
Older buildings are especially vulnerable to seismic damage. Retrofitting these structures often involves enlarging existing footings to support new shotcrete walls, strengthening columns and walls (sometimes using fiber-reinforced polymer, or FRP), adding shear walls, and reinforcing other critical components to improve earthquake performance.
4. Steel Frame Buildings
Steel frame buildings feature a skeleton of vertical steel columns and horizontal I-beams, offering durability and ductility. However, older designs can be compromised by brittle welded joints that fracture under seismic stress.
The structure can become unstable when cracks or failures occur in the connections between beams and columns.
Retrofitting these buildings involves reinforcing existing steel connections and adding new steel frames (sometimes with dampeners) to improve their resilience and maintain their structural integrity during earthquakes.
5. URM (Unreinforced Masonry) Buildings
Unreinforced masonry (URM) buildings are constructed from materials like brick, cinderblock, and hollow clay, but they lack the steel reinforcement (rebar) needed to withstand seismic forces.
This makes them dangerously rigid and prone to crumbling when subjected to ground shaking.
URM buildings often include load-bearing and non-load-bearing walls that break apart under stress, leading to collapse. Retrofitting measures, such as wall braces, anchors, and shear walls, can transform these high-risk structures into safer, more stable spaces for occupants.
Building Types, Risks and Solutions at a Glance
Seismic Retrofit Techniques
Retrofitting isn’t just about compliance—it’s about protecting lives and investments. Common retrofit techniques include:
- Reinforcing wall and roof connections.
- Adding steel braces, shear walls, continuity ties, and anchors.
- Strengthening exterior columns and welded joints.
- Installing moment frames or shear walls to stabilize open ground floors.
- Upgrading outdated materials to meet modern seismic standards.
Property owners can reduce risks by implementing these measures and ensuring their buildings are prepared for future earthquakes.
Steps to Safeguard Your Property
Preparing your building for seismic safety doesn’t have to be overwhelming. Follow these steps to take control.
Identify Vulnerabilities
Start by evaluating your building type and its unique risks. Factors like age, design, location, and materials can reveal critical weaknesses that need attention. Understanding these risks is the first step in developing a plan to protect your property and occupants during an earthquake.
Consult Experts
Bring in seismic retrofit specialists and structural engineers to perform a detailed assessment of your building. These experts can identify specific weaknesses, such as inadequate roof-to-wall connections, brittle materials, or insufficient reinforcement.
Their expertise ensures that no critical details are overlooked in your retrofit strategy.
Plan and Execute
Develop a tailored retrofit plan based on your building’s needs and the recommendations of seismic experts.
Once the plan is finalized, hire experienced seismic contractors to implement the retrofits and ensure compliance with modern safety codes and standards designed by the engineer.
Protect Lives and Assets with Expert Seismic Retrofits
Your business doesn’t have to face earthquakes unprepared. Saunders Seismic has over 40 years of experience retrofitting a variety of commercial building types.
Our team collaborates with engineers to deliver effective retrofit solutions for concrete tilt-ups, URM structures, non-ductile concrete, steel frame buildings, and soft-story buildings.
Contact Saunders Seismic today to schedule a consultation and safeguard your property against seismic risks.