Airports are important components of transportation systems and economies. As such, seismic safety for airports cannot be overstated. In seismically hazardous areas, airport infrastructures undergo meticulous planning and work in order to be as prepared as possible. Downtime following a seismic event can be decreased with appropriate measures, while the life safety of the infrastructure is improved.

Here is an overview of crucial seismic concerns an airport may face, the impacts earthquakes can have on an airport, and how seismic risk can be mitigated.

Seismic Concerns For Airports

There are many seismic concerns airports face, from soil liquefaction under runways to structural and nonstructural damage. Knowledge, management, and mitigation of risk are key to minimizing potential damage, maintaining functionality, and resuming operations sooner than later after seismic events. 

Following earthquakes of significant magnitudes, the soil can liquify and settle, which can result in runways cracking. This can cause them to be unusable for aircraft. Structures may sustain damage and collapse. Nonstructural systems may fall down without appropriate bracing, resulting in more extensive and expensive damage. 

Loss of airport functionality would not only impact the local economy and transportation, but can have national and international implications, as well. 

How Earthquakes Can Affect Airports

The consequences of a seismic event would depend on what part of the infrastructure is affected. When an earthquake strikes, airports evacuate terminals and close down until it is deemed safe to reopen and resume operations. While airplanes in flight are not physically impacted by earthquake activity, air traffic can be dependent on what happens on earth. When an earthquake happens, flights can be delayed, canceled, or redirected. 

Depending on the magnitude of the earthquake and how prepared the structures are, the airport may experience no damage, maintaining full operationality. It may maintain life safety while having experienced moderate damage with no collapse. In the worst case scenario, it may be a total loss, with complete collapse. Significant damage can result from unrestrained MEP systems, beyond loss of system functionality.

Airports in seismic zones must take appropriate measures to meet seismic codes. With proper preparation, potential damage in the event of an earthquake can be mitigated. This helps maintain functionality and reduces the downtime following a seismic event. 

Implementing Seismic Safety For Airports

Earthquake risk assessment is necessary for any airport in seismically hazardous areas. With proper risk assessment, appropriate measures can be taken to implement appropriate safety measures for airports. This extends from runways construction to the materials used in construction of terminals to seismic bracing of nonstructural systems, such as the mechanical, electrical, and plumbing (MEP) systems. 

Structural engineers of record (SEOR) and mechanical and electrical design engineers work together to meet performance delegations on a project. With coordination between the SEOR, MEP design firm, and bracing design firms, performance specifications can be met, even in congested areas of facilities. 

Improve Seismic Safety For Airports With VIE

VIE provides innovative seismic solutions to help clients mitigate hazards in their facilities. Among the hundreds of clients VIE has done work for over the past 40+ years are aircraft facilities. VIE is very familiar with the challenges such highly congested areas can present for nonstructural bracing, and is here to offer effective solutions to improve the seismic safety of airports. Our solutions have been tested by seismic events with success. 

VIE has been continuously doing work for the $4.5 billion Salt Lake City International Airport Terminal Replacement Project since 2019. The first phase of VIE’s work was put to the test when a 5.7 earthquake struck the Salt Lake City area in March 2020. The airport experienced minimal downtime in general, and no downtime for these non structural systems. To learn more about our work on the Salt Lake City International Airport, head over to our project page here: Seismic Bracing for the Salt Lake City International Airport.

To learn more about VIE’s seismic engineering services, please don’t hesitate to contact us today. 

While no one can predict exactly when the next earthquake will strike, taking measures to protect buildings with seismic bracing is always beneficial. It’s far more economical to mitigate damage than try to repair it after an earthquake. However, the financial impact of meeting seismic requirements often isn’t realized until after project budgets have been set and contractors are doing the work. Many teams are caught by surprise by new variables and their associated cost implications. 

VIE empowers clients to achieve cutting-edge bracing solutions while also reducing seismic bracing costs through innovative techniques. Our code-compliant designs provide clients with the least cost, most technically effective bracing that improve the safety of structures, reduce seismic damage, and limit downtime following a seismic event.

Factors Involved In Seismic Bracing Costs

There are many factors involved in seismic bracing costs. Some of which are as follows:

• Seismic bracing must meet code requirements. Code requirements vary from the state level to more stringent county levels. Code regulations safeguard life safety. Changes and adoptions of code and their related cost implications can catch project teams by surprise. 
• Concrete anchor attachment values have been reduced per the ASCE 7-16.
• Seismic bracing can be reduced or eliminated through in-depth understanding of requirements and effective design. Seismic code allows for exclusion of items if suspended tightly to the structure.
• Labor significantly impacts seismic bracing costs. Cheaper quotes do not always equal less expensive solutions. The more brace locations there are, the more labor is required to install the braces.

A Very Important Difference Between Higher And Lower Costs

Labor costs are a significant part of seismic bracing costs. When bidding on a project, there can be drastic differences between quotes. While companies may opt for (apparently) cheaper quotes in an effort to reduce seismic bracing costs, this is not always a less expensive solution. This is because the number of brace locations can drive up labor costs. 

More Locations = Higher Costs

To reduce seismic bracing costs, look to a reduction in bracing locations. VIE reduces the total number of brace installation through using actual loads, rather than conservative, upper-bound loads. Our use of advanced procedures can significantly reduce the load percentage.

For example, VIE’s designs show specific brace locations, rather than conservative designs that just call out very conservative bracing spacings. For most projects, VIE’s approach reduces the number of braces required by 30% or more than commonly used simplified methods. VIE’s engineers utilize more sophisticated analysis, such as to avoid bracing every tier of multi-tier trapezes. The use of specific brace locations reduces the total number of braces, which ergo reduces your seismic bracing costs. 

Avoid Over-Engineering And Increasing Project Costs

Meeting seismic requirements is more than simply meeting building code. Overly conservative designs meant just to meet code and that lack an in-depth understanding of code and its requirements can drive up project costs. While over-engineering may seem like the safe option, it is unnecessary and expensive. 

Working with engineering firms that understand code requirements and what is and isn’t necessary increases the preparedness of your structure for seismic events while also providing you with enhanced value. Effective seismic design necessitates practical understanding of seismicity and how structural and non-structural components respond. Such designs specify exactly where braces need to go, which prevents unnecessary bracing, and thus, prevents higher costs. 

Sophisticated Analysis And More Advanced Procedures To Reduce Seismic Bracing Costs

VIE Engineers compute actual loads and take into account dynamic properties of non-structural systems. This typically results in a reduction of 30% or more in brace locations in comparison to conservative designs. This reduces the overall cost of the project by reducing the amount of braces required, and more significantly, by reducing contractor labor costs required for brace installation. 

Our project-specific designs provide significantly enhanced value compared to the use of static design methods. Beyond the design itself, we understand design reviews may be needed. Our engineers provide field support throughout projects, including training contractors in brace installation at no additional cost. We eliminate confusion by specifying precisely which brace types are needed. 

We work with Connectors for Construction to provide seismic bracing kits, and specifically size and label them for specific locations on our drawings. Through working with professional engineers who understand project-specifics and actual load levels, you can reduce seismic bracing costs while ensuring your structure is as safe as possible. 

Contact VIE Engineers for more information about our seismic engineering services and the projects we’ve completed.

Earthquakes are one of the most destructive natural phenomena. FEMA estimates earthquake losses to be over $6 billion a year in the United States. While earthquake hazards cannot be controlled, the level of preparedness and effort devoted to developing, implementing, and enforcing building codes can be.

There’s a well-known saying: “Earthquakes don’t kill people – buildings do.” Expanded, it is: “Earthquakes do not injure or kill people. Inadequately built man-made structures can and do injure and kill people.” 

Building codes aim to mitigate the risk structures present. Seismic code development continues as better ways to enhance life safety conditions are uncovered, enabling the construction of safer structures.

About Seismic Codes

Seismic bracing is a crucial component of building design in areas prone to seismic activity. Proper bracing mitigates structural and non-structural damage in a seismic event, improving the safety of buildings and their occupants. Seismic codes set forth minimum design and construction requirements. 

Structures that meet minimum requirements should be capable of resisting earthquake loads without serious structural damage. Non-structural and architectural damages can be reduced with additional precautions. In addition to setting minimum requirements, building codes restrict or prohibit certain vulnerable types of buildings in seismically hazardous areas.

Seismic Requirements Can Vary

Seismic code requirements vary depending on the region and its local building codes, regulations, and guidelines. Most states and local jurisdictions adopt the building codes maintained by the International Code Council (ICC). They include: the International Building Code (IBC), the International Residential Code (IRC), and the International Existing Building Code (IEBC). New editions of the International Codes are published every 3 years. 

Who Sets Code Requirements?

In the United States, the International Building Code (IBC) sets minimum design and construction requirements. The American Society of Structural Engineers (ASCE-7) provides earthquake specific requirements. Some noteworthy seismic code requirements include:

• Plain masonry and plain concrete buildings without steel reinforcement are not permitted in moderate-to-high seismic hazard regions.
• Major mechanical, electrical, and plumbing (MEP) components are braced to resist earthquake loads and motion. 
• Buildings like hospitals, hazardous material storage facilities, and emergency structures are designed for at least 50% more seismic load than common buildings.
• And much more.

It is essential to understand and adhere to seismic requirements to enhance the safety and stability of buildings during seismic events. 

The History Behind Seismic Code Development

Building codes did not have earthquake design requirements prior to the 1906 San Francisco earthquake. Earthquakes were not mentioned in building codes until the Palo Alto Code in 1927. The Santa Barbara earthquake in 1925 was the turning point for seismic codes, due to the damage observed in buildings. In 1925, Congress gave the United States Coast and Geodetic Survey responsibility to investigate and report on seismology. This had significant effects on seismic code development. 

In 1933, the first mandatory seismic codes in the United States were published, following the Long Beach earthquake that same year, after extensive damage to school buildings. Since then, codes have been revised as new knowledge emerges in order to improve on the safety of buildings and reduce losses from earthquakes. 

Since these early earthquake events, code revisions have become much more organized. Every time a major seismic event occurs, findings from these events can lead to code changes. For example, the 1971 San Fernando Earthquake illustrated the vulnerability of “soft-story” concrete buildings and non-ductile concrete buildings. The 1994 Northridge earthquake illustrated that welded steel connections that were previously thought to be ductile were not and major code changes resulted. In these earthquakes and many others, the vulnerability of nonstructural items such as MEP systems and architectural items was apparent. Modern codes include measures to protect these items during seismic events.

Seismic Code Continues To Advance

Changes and additions to seismic codes continue to develop with new research and documentation of performance in past earthquakes. Even well-designed buildings can be damaged during an earthquake, depending on its severity. As such, seismic code development is crucial to provide higher protection and damage reduction, especially for critical facilities, such as hospitals. 

The Only Firm In Utah With Someone Nonstructural the Code Committees that Developed MEP Seismic Design Requirements

VIE Engineers doesn’t just read seismic codes – we also participate in seismic code development. We are the only engineering firm in the state of Utah that currently has someone on code committees. Through our direct involvement, this helps take advantage of code provisions for your benefits.

Our engineers use dynamic analysis and take advantage of methods in building code that most people aren’t even aware of. Our senior engineer, Mr. Masek, has been an active member of the ASCE 7 code committee, in addition to other professional activities for professional engineering organizations, such as the American Society of Civil Engineers, the Structural Engineering Institute, and the Earthquake Engineering Research Institute. He has developed seismic criteria for both new facilities and retrofits of existing structures. 

Contact us to learn more about our seismic engineering services and what we can do for you.