Scientists predict 2018 may be a tumultuous year for earthquakes. (Source: Take Two)

As structural damage is the leading cause of injury and deaths during an earthquake, architects, engineers and builders need to make sure buildings are built with the right materials and design.  

SEE ALSO: What it Takes to Build a Natural-Disaster-Proof House

The Materials

The most dangerous type of earthquakes are ones that trigger horizontal movements, because tall buildings are better at resisting vertical loads than horizontal ones. These ground motions can damage building foundations in a matter of minutes, causing severe injuries and deaths. Building a structure to withstand seismic waves starts with the right materials with the right properties, and steel is by far the most widely used material for building earthquake-resistant buildings.

According to the World Steel Association, ductile buildings are safer as they dissipate energy from seismic waves. A building will typically have ductile parts that can undergo plastic deformations without complete structural failure during an earthquake. Steel is the most common type of material for such parts.

Moreover, due to the law of inertia, the lighter the building, the less force seismic waves will exert on the building. That’s why it’s important, especially for taller buildings, to be made of light and flexible materials such as steel that can “bend” with the movement of earthquakes. On average, multi-story steel buildings are 60 to 70 percent lighter and 10 times stronger than concrete-framed buildings of the same size.

The Design

With steel, builders can add vital designs and reinforcements to keep the structure standing through an earthquake. Here’s some of the most widely-used measures.

Cross braces transfer the force of an earthquake to the ground. (Source: Earthquakes in India)

The structural integrity of buildings can be reinforced with steel cross braces that frame the exterior of a building in an x-shape. Ultimately cross braces can transfer the force of seismic waves back down to the ground, instead of letting the building take the hit. Builders can also reinforce the walls of buildings with additional vertical walls, or shear walls, that add stiffness to the frame of the building, allowing it to resist swaying or horizontal movements.

Base isolators absorb much of the shock of seismic waves. (Source: Embelton)

Base isolation involves separating the building from the foundation so that the isolators to absorb shock from the earthquake. The isolators allow the building to move at a slower pace because they dissolve a large part of the shock. Moment-resisting frames also effectively dissipate energy from floors and roofs to the building’s foundation and the stiff yet flexible frames can change shape during an earthquake. Although more costly, moment-resisting frames enable buildings to withstand an earthquake with excessive horizontal movement.

Putting it into practice with POSCO’s Steel House

In September 2017, Young Bae Kim’s home in Gyeongju province, Korea was hit with a 5.8 magnitude earthquake, just 8.9 km from where the earthquake started. Surprisingly, Kim’s home was unscathed. “I could feel the ground shake, but the house was completely under control.” Kim expressed.

Kim lives in one of the Steel Houses built by POSCO employees who volunteer to build homes and bridges for communities in need. Each Steel House is made with POSCO’s lightweight structural steel known for its durability, fire resistance and vibration resistance. The homes also incorporate PosMAC, a specialized galvanized steel that is 5 to 10 times more corrosion-resistant than standard steel and is more durable and affordable.

POSCO Employees volunteer their time to build steel houses in rural communities.

Because all the Steel Houses survived the Gyeongju earthquake while other homes were damaged, more and more people in Korea are choosing steel for their homes over traditional building materials such as wood and concrete. The same trend can be observed in Japan, where earthquakes are much more frequent. In order to build more earthquake-resistant buildings, steel is still the best solution available.

Cover photo courtesy of CNN.

SDGs are common goals of prosperity and development adopted by the UN in 2015 for the international society to achieve by 2030. There is a total of 17 goals, including eradicating poverty, quality education, good health and well-being, human rights and climate action.

The organization commended POSCO’s initiatives for tackling the housing crisis in its overseas and affiliate communities, and its commitment to improving the quality of life of local residents. Details of the POSCO Steel Village Project will be posted on the UN SDG official website, and if selected as the exemplary case of SDGs at the UN ministerial meetings, the project will be recorded in a permanent document of the UN as an example for other companies and organizations.

POSCO CEO Kwon Ohjoon said, “POSCO will carry out social contribution activities to help realize a better world in the best way we know how. As a global corporate citizen, we will fulfill our social responsibilities by aligning our goals with those of the UN SDGs.”

The POSCO Steel Village Project is a part of the POSCO 1% Foundation which uses POSCO’s materials and construction techniques to build houses, bridges and welfare facilities for people living in poverty. Over the years, POSCO has built steel houses, indoor playgrounds for children and steel bridges for the underprivileged living near its business operations in Korea and abroad.

Cover photo courtesy of the UN.

Weather Events of 2017

2017 saw some of the worst natural disasters across the globe. The Atlantic hurricane season hit hard, and Hurricanes Harvey, Irma and Maria were especially devastating. Hurricane Harvey caused 82 direct deaths, and an estimated USD 180 billion worth of damage. Hurricane Irma swept across 9 U.S. states leaving 75 people dead and damage costs of USD 50 to 100 billion. Hurricane Maria is the worst natural disaster on record in Dominica with the official death toll at 51, but over 900 cremations have taken place in Puerto Rico following the storm.

The aftermath of Hurricane Harvey shows the importance of resistant housing. (Source: CNN)

In addition, typhoons, tornados and other weather events wreaked havoc on communities around the globe raising awareness for the need for better emergency and disaster relief systems and stronger shelters to withstand natural disasters.

Natural-Disaster-Resistant Homes

For people living in areas prone to natural disasters, a resistant home can make the difference between total property loss and a safe haven. Worldwide, home builders and buyers alike are prioritizing the home’s ability to withstand natural disasters, leading to innovative architectural feats.

The Tsunami House was built to withstand natural disasters. (Source: My Fancy House)

On Camano Island in Washington State, the “Tsunami House” is made to be a safe waterfront home, able to withstand stormy waters. The main living level was built five feet above ground, and the foundations are built on pilings capable of withstanding high-velocity waves. The lower home area was designed with breakaway walls. For both strength and aesthetic purposes, this house contains steel inside and out, with composite and galvanized exterior siding, aluminum windows, and milled finish steel materials indoors. A steel staircase structure ensures safe passage.

The SURVIV(AL) House is sustainable and has a safe room in case of hurricanes or tornadoes. (Source: Inhabitat)

Another example of a home built to survive natural disasters is the SURVIV(AL) hurricane proof house is a solar-powered home with a steel-encased safe room built to withstand the effects of extreme weather like hurricanes and tornadoes. Students from the University of Alabama created this home with a safe room that can withstand a two-by-four plank landing at 200 mph.

The Ophir home sits on a hillside with exposed steel frames to withstand earthquakes. (Source: Inhabitat)

The Ophir home was built in 2010 by a couple in New Zealand following a 6.3 magnitude earthquake that forced many people from their homes and community. The couple, however, built their home back up from scratch, but this time, made sure it would not collapse under any circumstances. Not only can the home withstand earthquakes, it is designed to maximize exposure to sunlight for sustainable living as well. A distinctive feature of the home is its exposed steel frames that support the concrete walls.

The Benefits of Building with Steel    

Steel is one of the most popular materials for construction, but its properties make it especially valuable for natural-disaster-resistant homes. Steel has a high strength to weight ratio for durability, without the heft and its associated transport costs. It requires very little maintenance, even when used as an exterior surface, and will withstand the effects of time. It is also an eco-friendly, cost-efficient material for construction.

Steel Frames are ideal for the construction of natural disaster resistant homes. (Source: Stratco)

In fact, steel can withstand forces up to 150 mph as an exterior material, without becoming damaged. Steel is also an excellent reinforcement when used with concrete, offering the stiffness, strength and ductility needed to help a building withstand damage from events like earthquakes. As part of a building’s foundation structure, steel reinforcements help anchor the foundation, and the entire home, keeping it where it belongs through wind, waves, quakes and rain.

The damage left behind by natural disasters this year show that the effects last well beyond the initial onset. While there is no such thing as a completely weather-proof building, steel can offer a great deal of security and help minimize the destructive outcomes of Mother Nature.

Cover photo courtesy of CENHS.