Buildings must be designed to withstand the powerful forces that come with seismic movement. Ductile materials like steel are favored, allowing buildings to bend rather than break.
Innovative technologies like shear walls, cross braces and diaphragms redistribute the forces that travel through a building during shaking. Other technology such as moment-resisting frames allow columns and beams to flex while their joints remain rigid, providing flexibility to absorb seismic energy.
Enhancing Structural Integrity in Seismic Zones
When building structures in seismic zones, flexibility is a key consideration. Wood, steel and concrete all have greater flexibility than brick or unreinforced masonry walls, which tend to crack under stress and are not suited for earthquake resistant buildings. Lightweight roof structures can also reduce the stress placed on a building during an earthquake.
Earthquake-resistant buildings can be further strengthened using various design techniques and innovative materials. These include cross bracing that transfers seismic waves to the ground instead of letting them strike and shake walls or floors. Damping systems or energy dissipation devices are inserted between a building’s foundation and the ground to isolate the structure from vibrational forces.
Scientists are working on new types of materials that can further enhance seismic resistance in buildings, including shape memory metal alloys that retain their shapes under stress and carbon-fiber wraps that strengthen structural elements. Engineers at the University of British Columbia recently developed an eco-friendly, fiber-reinforced cementitious composite that can dramatically improve the strength and ductility of existing brick and concrete structures when applied as a thin coating on their surfaces.
Common Materials for Earthquake-Resistant Buildings
When building in seismic zones, engineers and architects recommend using construction materials that are innately earthquake resistant. This can be achieved with the proper design and materials in a new structure or by retrofitting older structures.
The most common recommendation is to build with concrete and steel. The ductility of these materials allows them to bend and absorb the energy caused by an earthquake, rather than letting it break the structure and possibly crushing those inside.
Other materials such as wood and foam can also provide a building with great seismic resistance. These materials gia da hoc are often used in a system known as “base isolation,” which separates the building from its foundation by use of springs or runners to allow the building to move but not impose stress on the base of the building. Other techniques for enhancing seismic resistance include shear walls, cross braces and diaphragms that redistribute the force of shaking throughout the building’s structure.
Strategies for Seismic Resilience in Construction
In addition to constructing buildings with more resilient materials, engineers also incorporate other techniques into the design of seismic-resistant buildings and homes. For example, diaphragms, which are built into floors and roofs to distribute sideways forces, help absorb seismic energy.
Another recommendation is to build structures with ductile parts that can undergo plastic deformations without structural failure during an earthquake. These parts, which are typically made from steel, dissipate seismic waves by absorbing and redistributing their energy.
Engineers are also experimenting with sustainable building materials such as the sticky yet rigid fibers of mussels and bamboo, as well as 3D printed shapes that can interlock and provide a flexible structure for earthquake resistance. Researchers at the University of British Columbia have developed a fibre-reinforced concrete called eco-friendly ductile cementitious composite (EDCC), which is more malleable and ductile than traditional reinforced concrete. The material is able to change shape under stress and can be used to make seismic-resistant walls, floors and ceilings.
Importance of Seismic-Resistant Building Materials
Earthquakes are a major risk to people living in earthquake-prone regions, but building structures can be made stronger and safer from this disaster. Many techniques for earthquake proof buildings involve reducing or redirecting the force of seismic waves. A ductile cementitious composite, for example, can strengthen concrete and even make bricks better at resisting horizontal stress.
Other methods include using shear walls to transfer vibrations, cross bracing to resist lateral forces and designing floors as diaphragms to absorb energy and disperse it into strong vertical elements. Moment-resisting frames are another crucial part of reinforcing a building to keep it from collapsing in an earthquake.
While the conventional wisdom was once that the heavier the building, the more it would withstand an earthquake, new construction methods have shown this isn’t necessarily true. Lighter materials, such as steel, can withstand more than traditional concrete and bricks. They can also be more flexible and change shape during an earthquake.