Why Building Codes Aren’t Enough for Seismic Activity

Why Building Codes Aren’t Enough for Seismic Activity

We all know that building codes are designed for the safety of lives. That’s obvious. However, they are not specially designed to protect your property, investment, and finances. 

That’s why building codes aren’t enough. There are limitations, and these limitations could cause huge personal issues.

What Do Building Codes Actually Guarantee?

Building codes in earthquake-prone regions (like California’s IBC/CRC seismic provisions) guarantee life safety. They are carefully designed so a building intended to such code is unlikely to collapse in a design-level earthquake. 

The Limitations of Building Codes in Seismic Zones 

While building codes are great for general building, in Seismic Zones, they’re unpredictable. Therefore, a code-based approach has several limitations. 

Risk of Collapse Still Exists

All in all, building codes don’t eliminate the risk of collapse. Really, they only reduce it to a level that regulators (those who create the codes) deem as an “acceptable” level. 

The code’s overall philosophy is to make a collapse unlikely. However, unlikely is not impossible. Therefore, even if you build a house to seismic code, it may still collapse. 

For example, a modern, code-compliant building may have a low probability of collapsing during a “maximum considered earthquake”. But what if the earthquake is more severe than what the code anticipated? Well, failure can occur. 

Without question, it’s very sobering when you realise that “code-compliant” doesn’t mean “zero chance of collapse”.

No Protection for Financial Loss or Downtime

A huge surprise to property owners is that, even if your property is code compliant, it can still collapse, causing financial loss or downtime. 

What the law cares about the most is that people survive. It doesn’t really care about whether the building is usable or cheap to fix after seismic activity. 

As a result, for non-structural features, like cladding, drywall, ceilings, mechanical/electrical systems, plumbing, etc., they have minimal to no code requirements to keep them protected. 

For example, after the 1994 Northridge earthquake, many commercial buildings structurally survived. They were, however, shut down and unable to be used due to internal damage, such as in their fire sprinkler systems. 

Alongside this, building code doesn’t account for loss of income or relocation costs if your building is unusable. If your home, apartment, or business has to close for a year for repair, that’s not a code violation; it’s an expected outcome under the “life-safety” objective. 

Codes Don’t Prepare for Worst-Case Earthquakes

Building codes use probabilistic criteria. Therefore, they prepare us for strong earthquakes but not the absolute worst-case scenario. 

Generally, structures are designed for a certain level of ground shaking. This is often measured using past data, but larger-than-ever earthquakes are possible. 

Older Buildings Are Often Exempt from Code Updates

Sometimes, older buildings are grandfathered under the codes that were in effect when they were built. As a result, they don’t get updated with “new codes”. 

This is only in some areas, though. The Greater San Francisco Bay Area and the Greater Los Angeles Area for example, push homeowners to retrofit their older homes through an incentive program. 

Still, this is only an incentive program. Though it can reduce the costs of seismic retrofitting for older homes, it isn’t mandatory. 

Example of Building Codes Not Being “Enough” 

Time after time, real earthquakes have exposed the issues between code-compliant properties and actual outcomes. 

Some of the most popular examples include: 

Northridge Earthquake (1994, M6.7) 

At the time, California’s seismic building codes were the most advanced in the world. However, in 1994 in Northridge, CA, an earthquake exposed weaknesses in the code. 

One of the key issues was non-structural and infrastructure failures. While most modern buildings didn’t collapse (which was to code), the economic losses were estimated to be around $20 to $40 billion. 

For example, many hospitals in the region were built to code. However, they still had to shut down because of many broken utilities and sprinkler flooding. 

Loma Prieta Earthquake (1989, M6.9)

Bay Area seismic building codes also failed back in 1989 in Loma Prieta. The main issue here was with pre-code buildings, which are mostly buildings built in the 1930s. 

Instead of retrofitting them to modern compliance codes (in those times), they were grandfathered to their almost codeless design. As you can imagine, the magnitude 6.9 quake hit this region during these times, and most of these buildings collapsed. 

South Napa Earthquake (2014, M6.0)

The South Napa earthquake in 2014 was looked at as a success. A lot of the modern buildings (Napa has mostly buildings built post-2000) survived. 

Despite the lack of collapses, however, there was a ton of non-structural damage. There were still ceilings that fell, sprinkler pipes that burst, and more. 

In fact, there was only one fatality in South Napa during this quake. This fatality was caused by non-structural damage. 

What is the Solution to Building Codes for Seismic Activity? 

As you have seen, relying on building codes leave us with potential collapse risk, crippling non-structural damage, and several other vulnerabilities. Because of this, we need to go beyond the code for true earthquake resilience. 

Luckily, we can do this by embracing a performance-based approach to seismic design and retrofit. This Performance-Based Design (PBD) focuses on real-world performance outcomes instead of following a “generic” recipe.

With such a design model, which follows FEMA’s P-58 methodology, you define what you want your building to achieve in an earthquake. This allows you to go beyond the “code” requirements and to actual performance-based designs. 

How Performance-Based Design (PBD) Can Help 

Focuses on Real-World Outcomes

Unlike predictive codes, PBD looks into how a building will perform during and after an earthquake. 

Therefore, instead of a one-size-fits-all type of methodology, engineers use simulations, nonlinear analyses, and historical data to predict damage to both structural and non-structural elements. 

By doing such a thing, a PBD lets you set realistic performance objectives. For example, ensuring a hospital can reopen within 24 hours or a warehouse within a week, etc. 

Alongside this, you can set clear performance goals with a PBD. This allows you to protect what matters most to help minimize potential repair costs. 

Quantifies Downtime and Financial Risk

Another huge advantage of PBD is the ability to estimate how much damage and downtime a building may experience in a real earthquake. 

Simply, traditional building codes can’t answer such questions. For example, “How long will this structure be unusable?” or “What will it cost to repair?”, etc. A PDB, however, can set probabilistic projections for repair time, cost, and so forth. 

This, as you can imagine, allows you to design more strategically. Even a slight change in design could save millions in repair costs or missed revenue. 

Enables Smarter, Site-Specific Design

Depending on where your building is located, codes can give broad assumptions across entire regions. These, however, aren’t specific enough.

A PBD, on the other hand, factors in everything. This includes soil conditions, fault proximity, tsunami risks, and various other unique variables specific to your building and location. 

Such an approach allows you to make smarter choices when it comes to design, factoring in all environmental, structural, and seismic factors. 

Building Code Vs Performance-Based Design

Feature	Building Code (Prescriptive)	Performance-Based Design (PBD)
Primary Goal	Life safety (prevent collapse in major earthquakes)	Life safety plus reduced damage, downtime, and loss
Design Approach	Follows predefined rules and minimum standards	Tailored to meet specific performance goals
Damage Expectations	Accepts significant damage as long as collapse is avoided	Seeks to minimize both structural and non-structural damage
Post-Earthquake Usability	May be unusable for weeks or months	Can be designed for immediate or rapid reoccupancy
Risk of Downtime & Repair Cost	Not addressed	Estimated and designed to reduce
Non-Structural Components Considered	Limited or optional	Fully included in performance evaluation
Customizability	One-size-fits-all based on generic site conditions	Customized for building type, location, and owner priorities
Applies to	New construction (mostly)	New and existing buildings; ideal for retrofits
Financial Protection	Offers no insight into financial loss	Quantifies potential losses and enables mitigation planning

Contact Us Today 

Understanding the gaps in building code is just the first step. The second step is contacting a seismic retrofit professional, like us, Avant-Garde, to develop a performance-based retrofit plan. 
Therefore, contact us today and ensure that your property is above code for unexpected situations. Let us give you peace of mind knowing your building is truly prepared regardless of the severity of the earthquake.