HOW TO CONSTRUCT EARTHQUAKE RESISTANT BUILDINGS
Standard and conventional buildings are built to resist the weight brought on by gravity. However, when there is an earthquake, the movement and shaking of the earth leads to the building moving in both directions horizontally. With this movement, it may result in the building collapsing on top of itself or that the structure still stands but the non-structural elements collapse such as the walls, which may harm those who are inside the building. For this reason, it is crucial to understand the construction methods to erect buildings that are resistant to earthquakes, whether it be newly constructed or reinforcing those that are existing.
How does seismology affect a building?
The most important thing to keep in mind is that earthquakes are an unavoidable natural phenomena. According to a statement made by Amadeo Benavent, A professor of structures at the Escuela Técnica Superior de Ingenieros Industrial (Technical School for Industrial Engineers) at the Universidad Politécnica de Madrid, he stated that even though it is not possible to predict when an earthquake may strike, it is proactive to construct buildings so that the damage caused can be controlled. In that way, it is at least possible to avoid people dying as a result. The inefficiencies of a building are usually produced in the following order:
- The Earthquake produces lateral movements, for which the building it not prepared.
- The damage to a building is concentrated mostly on one floor, mainly being the ground floor.
- The damage to the ground floor cannot support the vertical load of the rest of the building and it collapses as a result.
Are there any rules to regulate constructions?
It is essential to design new constructions and recondition those that are already in existence, following the current legislative order. Currently, in Europe, the existing rules are called “Eurocode 8: Design of structures for earthquake resistance”, which establishes a series of rules to design buildings that are resistant to the possible earthquakes in the zone. Eurocode 8 is a European legislation that still has not been adapted in Spain. However, there are still many loose ends to tie up because the regulation only makes reference to how new buildings should be undertaken, not to mention all of the current buildings that are already in existence.
How to make a building more resistant
One type of seismic-resistant building, more commonly known as earthquake resistant, seeks to balance out two factors: resistance and plasticity or flexibility. On one hand, these constructions aim to resist earthquakes that occur unexpectedly with a construction that is strengthened and fortified to the movements of the tectonic plates. On the other hand, they are buildings that seek plasticity or flexibility, meaning the ability to be slightly deformed without collapsing, making it possible to support the lateral movements of earthquakes.
However, it is necessary to keep in mind that the structural issues involve damages and if the structures are too flexible and there is a moderate earthquake, the damage may reach an excessive level. With that in mind, the objective is to achieve an appropriate combination between resistance and flexibility, for that reason, it is important to balance both factors.
The principal objective is for the building to be resistant to collapsing and not harm any people within the building, even though it may suffer damages that require repairs or possible demolition. For that reason it would be necessary to construct larger beams and pillars made with a larger amount of steel, as well as connect the building cement to be designed in both directions in the form of a cross. Also, to have greater flexibility, the pillars should be more resistant than the beams which should be made of flexible material and the non-structural elements such as walls should be well anchored to the structure of the building but without limiting the flexibility of the structure itself and lastly, the pillars and beams should be adequately joined together.
If the building already exists and the aim is to adapt it to an earthquake resistant system, there are a series of solutions to reinforce the resistance of a building. The following is a list of those possible solutions, among them are the more conventional and achievable and those that are more complicated (as well as more expensive).
- Conventional solutions
- Add structural walls using reinforced concrete
- Add diagonal bars
- Add side walls next to the pillars
- Reinforce pillars or beams with steel, cement or a mix of resin and fibre.
- Complicated Solutions
- Install power heatsinks
- Support the building on rubber elements
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