About seismic constructions
Reinforced concrete buildings constitute the majority of structures studied and built in Greece at least until the late 1970s. A significant number of these buildings, during earthquakes that have occurred in the period from their construction until today, have suffered more or less extensive damage. The physical damage that a structure suffers over time, if there is no provision for proper maintenance and possibly reinforcement, reduces the strength of the structure to withstand seismic loads. As a result, a progressively increasing number of existing structures are found to be in need of seismic loads.
A large number of constructions and technical infrastructure projects worldwide are approaching the limit of their conventional lifespan and therefore need control and possibly intervention in order to restore their static adequacy. The rapid aging, especially of structures in unfavorable, highly corrosive environments, makes the need for surgery even more urgent. Apart from the natural causes, other factors that contribute significantly to the decision to intervene are the change of use of a structure, as well as the increase of the seismic requirement imposed by the new seismic regulations, especially for structures located in areas of increased seismic risk. The most efficient application of the available methods for the repair and reinforcement of structures presupposes the use of materials and technologies through which the static adequacy of the structure can be restored or at least improved in an economical and efficient way. The materials used mainly for this purpose are concrete and steel.
Comparative advantage of steel (metal construction) over concrete (concrete):
- Architectural flexibility compared to conventional constructions that do not have the capacity for large openings. It allows the housing of buildings with large openings (ie without intermediate columns) with the construction of relatively low beams, which is often impossible in reinforced concrete structures.
- Superiority in the degree of seismicity – The structural elements of metal structures are produced in industrial units that fully meet the required specifications. In all other constructions (concrete, stone, wood, etc.) the strength is checked at the construction site or in a laboratory. Therefore only structural steel has a specific strength, uniform and stable, ie it is a more reliable material. This is also taken into account by the regulations on safety factors. Due to its superstructure, ie the many points – nodes that connect the frame, it is provided more security statically and this because even if there is a failure at one point (which practically does not happen), the building is hardly affected at all. Unlike a conventional building, collapse would be inevitable. The elements of the prefabricated building are made in a special covered space and then transported to the construction site for installation and welding. metal structures are lighter than conventional ones. This has the following advantage. The action of an earthquake in a building depends on a seismic factor and the mass of the building, therefore its weight. Therefore, the lighter a structure is, the less stress it exerts during an earthquake and the less permanent deformation it receives.
- In a composite structure, even in the event of damage after an earthquake, replacing a member (Metal column-Metal beam, etc.) is a process of a few days, compared to conventional structures where when a member (Kolona – Dokari) is damaged by the earthquake, it is destroyed and there the restoration of damages is impossible.
- Because they are light constructions they are suitable for use in additions to existing buildings which is impossible in prefabricated buildings (Prefabricated houses). In most cases, reinforcement of the existing building is not required due to the low weight of the metal frame and the construction materials (YTONG masonry, dry construction, etc.)
- Smart Building after years of experience and research in the field of construction and in collaboration with the National Technical University of Athens (NTUA) has established in its construction the external thermal insulation. External thermal insulation achieves excellent energy indicators based on the restrictions established by KENAK in recent years on building permits. The Thermal Facade embraces the building from the outside so that changes in the outside temperature find an obstacle and do not pass to the building materials, which have no thermal insulation properties by themselves, something that happens in prefabricated houses where the insulation is in the middle of the masonry.
- Provides a reduced contribution to IKA stamps (50% less than the conventional one).
- High construction standards – In composite construction, metal components are manufactured in the factory under the supervision of human resources as well as computer programs. The steel production criteria follow international standards, bearing certifications (ISO) and are also controlled by state bodies. Otherwise in conventional construction the strength is checked at the construction site or in a laboratory. Therefore only structural steel has a specific strength, uniform and stable, ie it is a more reliable material.
Types of damage to reinforced concrete (concrete) buildings:
The method chosen to repair a component that has lost its strength due to seismic action is directly related to the size of the damage, as this determines both the remaining bearing capacity and the available safety margins of the damaged element. Reinforced concrete load-bearing elements can have three typical degrees of earthquake damage:
- Simple cracking: The component shows either single small cracks of small width (& lt; 2 mm) due to minor reasons and local weaknesses (eg concrete break joints).
- Partial disorganization: There is intense cracking of large width, as well as local disorganization of the concrete by compression or shear. The remaining deformations are very small.
- Continuous interruption due to complete disorganization of concrete or reinforcement damage .
In the way of construction with metal construction, the above earthquake damages that a building can suffer, are reduced or eliminated due to the high strength and flexibility of steel. Steel structures have been used successfully in Europe since 1950. Today’s steel structures represent many years of research, testing, and structural improvements. Metal structures are excellent mechanically and do not forget that steel has been used for many years in large buildings with durability (commercial buildings, skyscrapers, stadiums, etc.).
The structural elements of the metal structures are produced in industrial units that fully meet the required specifications. In all other constructions (concrete, stone, wood, etc.) the strength is checked at the construction site or in a laboratory. Therefore only structural steel has a specific strength, uniform and stable, ie it is a more reliable material.
This is also taken into account by the regulations on safety factors.
Metal constructions are lighter than conventional ones. This has the following advantage. The action of an earthquake in a building depends on a seismic factor and the mass of the building, therefore its weight. Therefore, the lighter a structure is, the less stress it exerts during an earthquake and the less permanent deformation it receives.
What does Smartbuilding offer to choose it for an earthquake construction:
Smartbuilding is the ONLY company in Greece that offers design and construction for 100% anti-seismic houses according to the latest anti-seismic regulation. In each new building study, an inspection of this building is performed in earthquake situations with state-of-the-art computer programs owned by the company and they simulate the model of each building in each possible scenario of natural disaster. So your construction is stable and safe before it is even implemented and built.
Smartbuilding also offers seismic adequacy prevention, ie pre-seismic reinforcement of existing buildings that have been studied with old seismic regulations, in order to reduce the possibility of damage and prevent collapse in a future earthquake. Due to the regular review of the Greek Earthquake Regulation (EAK) almost every 4 years, it is considered necessary to upgrade the projects completed by the company.
Finally, Smartbuilding undertakes the reinforcement of buildings that have been damaged either due to earthquakes or due to natural damage or age. The method of Non-Destructive Tests determines the strength and density of the reinforced iron as well as the concrete of the old construction in order to study its model and to strengthen the respective columns or beams that need reinforcement. A similar procedure is followed by our company for the reinforcement of buildings that have been affected by an earthquake. The excellent training of our engineers, as well as their experience, make our company as a key partner for every citizen who wants to strengthen the space, to expand his residence or a combination of them. The metal construction is suitable for the extension in height or horizontally of houses. In addition to the reinforcement and construction of newly built buildings, our company undertakes due to the flexibility and technological superiority of the metal frame and the innovations it has introduced after years of research, height-added constructions (floors) and horizontally (rooms on the same level) in existing homes.
Below you will see a sample of our projects as well as in the building systems repairs-reinforcements-additions to existing ones.