Why steel frame buildings perform excellent against earthquakes?

19-Jul-2016 05:30 am 0

Earthquakes spell the horror like no other force of nature. This single seismic event can alter the natural landscapes as well as man-made buildings with considerable intensity. After years of research and studying the earthquake engineering techniques, it is possible to make buildings with earthquake-resistant features. Thanks to the application of steel frames in the buildings that perform excellently against earthquakes to increase the chances of survival.

What makes Steel framed structures excellent at resisting earthquakes?

Most of the steel construction is done using mild steel which is a very strong material. This helps to combat the seismic effect of earthquake much better than any other material. Research has shown that steel behaved exceptionally well against an earthquake as compared to other materials on a global scale. Steel is favored earthquake resistant material due to its following properties –

  1. Immense Strength: Steel offers an exceptional strength that is why steel building rarely gets deformed. They offer brilliant resilience to the seismic events due to their material and geometric properties.
  2. Flexibility: The key feature of steel framed buildings is contributed by the flexibility of steel. It can flex, bend sideways without cracking and deform but never collapse. There is a rare chance of failure or collapse of steel framed building that is why they are hugely favored for residential and industrial earthquake resistant structures.
  3. Stability: Steel is much stable material due to its chemical composition. Once a steel framed building is formed, it will stand tall through the natural calamities and there will be virtually little or no change in the dimensional properties. There is rarely any scope of weak spots or cracks in steel structures during earthquakes.
  4. High ductility: The high ductile property of steel contributes to extended deformation capacity of the structure. This makes the energy dissipation in steel structures better than other material making steel framed structures to have more reliable seismic behavior.
  5. Low weight: Heavier structures attract larger forces in the event of an earthquake. This causes them to fall apart. Steel is lower in weight. Since the seismic forces are linked to inertia and consequently to the mass of the structure, if we reduce the mass, it will lower the seismic force too. In case of steel structures with hall, an envelope is created over a large area and the weight per unit of the surface area becomes less. This means that the building is governed by wind forces and not the seismic ones. So as compared to heavy materials, buildings designed for wind and gravity loads with steel have better performance during an earthquake.
  6. High strength to weight ratio: Steel is known for its high strength-to-weight ratio as compared to other building materials. If compared to wood, a steel frame is one-third of its weight. During a seismic event, less weight will be required to move and also there will be less weight to stop. So whatever the damage caused due to inertia will be greatly reduced during an earthquake.
  7. Non-combustible: Since steel is non-combustible, it does not promote fire breakouts during an earthquake and if there is one, it does not help promote it any further.

Steel offers better structural integrity over other building materials. This is why it can stand the seismic forces better than others. Therefore, while designing an earthquake resistance structure, robust steel frames should be the top consideration.

Summary
Article Name
Why steel frame buildings perform excellent against earthquakes?
Description
Steel's durability and ductility make steel the best building material. It has the highest strength-to-weight ratio of any other building material, which makes it suitable for buildings both large and small.
Author
Publisher Name
SME Digest

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