This year marks the 50th anniversary of the Great Alaskan Earthquake. As the second strongest earthquake in recorded history, it had a moment magnitude of 9.2. It lasted 4 minutes, 38 seconds and caused ground fissures, collapsed structures, and initiated a tsunami that killed 131 people. Because the epicenter was so close to Anchorage, only 75 miles away, there was a lot of structural damage. In addition, the airport control tower and the runway were both severely damaged forcing the airport to close down.
Earthquakes are especially damaging to buildings because the shaking of the ground causes movement in directions that are very difficult to predict and protect against. The magnitude and length of the earthquake are factors that contribute to the resulting damage. The longer and stronger the earthquake is, typically the greater chance for damage. The type of soil below the building may also contribute to the damage factor. If the soil is thick, soft, or wet the shaking will increase. Typically, high-rise buildings are more affected by slow shaking and smaller buildings are more affected by short and frequent shaking. Preemptive measures are taken by the government, who issues updates to seismic codes to increase strength for both compression and tension. Buildings are then upgraded and reinforced to ensure compliance.
Seismic upgrades include traditional steel and concrete reinforcement, to strengthen steel beams, widen concrete columns, and to increase in-plane and out-of-plane strength of wall slabs. A less costly solution, and one that adds virtually no weight to the building is HJ3’s Civil and Commercial carbon fiber reinforcement. One example of a seismic upgrade where HJ3’s system was used was a historical pub in Salt Lake City, Utah. The pub had several unstable floors from a previous fire and the unreinforced masonry walls needed strengthening to meet the new seismic codes. The owner wished to preserve the historic look and feel of the brink making the job a bit more difficult. To provide the correct reinforcement and preserve the historical feel, HJ3 used a translucent glass fiber strengthening system.
First, the interior surface of the wall was cleaned with a dry ice abrasive blast. The walls were then primed and the glass fiber reinforcement system was installed. The exterior of the building was abrasive blasted and power washed before being primed. HJ3’s carbon fiber reinforcement system was then used as reinforcement.
By using HJ3’s carbon and glass reinforcement systems, this historical pub was able to increase both the in-plane and out-of-plane strength of the masonry walls, meeting the new seismic codes. Any building can benefit from reinforcement if earthquakes are a concern. Both the carbon and glass reinforcement system are cost effective solutions that can exceed the seismic requirements. On average, customers who repair with HJ3’s Civil and Commercial products save over 50% compared to replacement or other repair solutions. If you have earthquake concerns or need to bring your building up to seismic code and would like to learn more about HJ3’s glass and carbon fiber reinforcement systems, contact our project managers today at email@example.com.