Buildings need to withstand not only the weight of occupants and support frames, but also horizontal waves of force that can damage walls and collapse structures. To prevent such damage, shear walls, cross bracing, diaphragms and moment-resisting frames redistribute forces throughout the building.
Steel and metal buildings with strong construction joints have a better capacity to resist the destructive forces of an earthquake. But other materials can help too.
Architectural Metals
Architectural metal is used in buildings for ventilation and heating systems, but it can also be a key element in making a building more resilient to earthquakes. It is not subject to the same wear and tear that other building parts experience, so it is less likely to cause damage during an earthquake. It is also typically attached to the structural frame of a building using fasteners that are resistant to seismic activity.
To resist collapse, buildings must redistribute forces that travel through them during an earthquake. Shear walls, cross bracing, and diaphragms are all useful in this endeavor. In addition, damping systems can help absorb and dissipate seismic energy to minimize the force that is transmitted up through the structure.
Another way to increase the resilience of a building is to conduct regular inspections. This can help identify potential problems and repair them before an earthquake occurs. It is also a good idea to choose a building material that will protect against earthquakes, such as steel or bamboo. Building safety is a critical aspect of any home or office.
Bamboo
Bamboo is a versatile, affordable building material that can be used for framing, flooring, and thatch cladding. Its resilience in earthquakes is due to its wide-ranging roots that penetrate deep into the soil, the flexibility of bamboo canes and branches, and the narrow leaf blades that intercept wind better than timber.
Its ductility, or ability to absorb energy and return to its original shape, makes it a sustainable alternative to metals in seismic design. Using bamboo in building structures also promotes local economic development and can prevent the need for foreign imports, thereby protecting currency reserves.
However, despite these positive effects, bamboo must be properly designed and constructed to achieve maximum benefit in earthquake-prone regions. As a result, it is important to work with specialists in sustainable construction and earthquake engineering to ensure that buildings are safe. In addition, some eco-friendly materials may have higher upfront costs than traditional building materials, but the long-term savings often offset this initial investment. The use of sustainable materials can also help reduce carbon footprints and contribute to a healthier living environment.
Recycled Steel
While conventional wisdom is that the heavier a building is, the safer it will be in an earthquake, recent seismic studies have shown that buildings with less weight are actually better at resisting damage and collapse. As the earth shakes, tectonic plates slam against buildings, their own weight creating a force that stresses foundations, walls, and connections. Buildings made of concrete have high compressive strength but low tensile strength, so they are reinforced with steel to handle this force.
Buildings constructed from steel and other metals have greater flexibility than concrete, allowing them to bend rather than break during an earthquake. This makes them easier to pass seismic tests and meet building codes in earthquake-prone areas.
In addition to their ductility, wood buildings also weigh less than buildings made from concrete or steel, decreasing the inertial forces an earthquake generates. Plus, the many nail- or other metal-connections in wood construction provide redundant load paths for extreme forces, reducing the chance of a building failure if one connection fails.
Shear Walls
During an earthquake, the ground moves and slams against buildings, creating force that can tear or uplift them. In order to withstand these forces, shear walls are used to resist lateral and uplift forces.
Shear walls are made of wood, concrete, or steel, and can be solid or lattice. They also have different configurations based on their load-bearing capacity. Solid shear walls have no openings, while lattice shear walls have multiple entrances. Concrete shear walls have high load-bearing capacities and are often used in large buildings.
A shear wall can be reinforced with diagonal cross bracing. These cross braces connect shear walls and a building’s frame to keep it from collapsing during an earthquake. Steel is a common material for these cross braces, which can withstand compression and uplift forces. In addition, they’re able to dissipate the energy of an earthquake. This is because they’re ductile, meaning they can be bent or deformed without causing complete structural failure. In contrast, other materials like concrete can be brittle and break under these forces.
Cross Braces
Buildings are designed to withstand the weight of occupants and above-ground forces, but they also need to withstand underground vibrations and horizontal waves of force that can damage walls, support frames and foundations. The conventional wisdom was that the heavier a building, the safer it would be in an earthquake, but research has shown that buildings made with light materials are more resilient to these forces.
Steel is an excellent material for building structures that can withstand earthquakes, due to its combination of strength and flexibility. It’s particularly effective in buildings with a diaphragm, which is an essential design feature for resisting horizontal loads and pushing them to vertical structural elements like columns and beams. Another important structural feature is moment-resisting frames, which add flexibility to a structure by allowing columns and beams to bend while keeping their joints rigid.
Finally, seismic dampers, which are similar to shock absorbers found in cars, help reduce the impact of earthquakes by dissipating energy. These devices have piston heads inside a cylinder filled with silicone oil that move up and down, converting the seismic energy into heat to protect the building.