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Questions About Earthquake Isolation
Earthquake isolation (also called seismic isolation, seismic isolation or base isolation) is a system that protects the structure and all components inside the structure from the destructive effects of earthquakes by creating a layer between the structure and the ground, thanks to special devices (earthquake isolation devices) placed between the structure itself and its foundation. method. Earthquake isolators (also called earthquake isolation devices, seismic isolators or base isolation devices) are placed in the structures, one for each column and more than one under the curtain walls, and the superstructure is separated from the foundation and the ground.
Earthquake insulation increases the period of the structure to which it is applied, thanks to the flexibility of the devices in the lateral direction, and meets the horizontal displacement demand that will occur in the event of an earthquake at the isolator interface (with earthquake insulation devices). In addition, the damping rate, which is accepted as 5% in normal buildings, plays an extra role in reducing the destructive effects of earthquakes by increasing 20% or more when it comes to earthquake insulation.
Earthquake insulation protects both the structural and non-structural elements of the superstructure and thus ensures that the structure survives any earthquake with zero damage and remains fully functional. Earthquake isolation is the only proven and applicable method that can simultaneously control the relative storey drifts and storey accelerations in a building. In addition, earthquake insulation is the only method that ensures that the structure and all its components (structural and non-structural elements) survive the largest earthquake expected in the region with zero damage, thus guaranteeing the uninterrupted use of the structure after any earthquake. You can access the image that compares “Earthquake Resistant Design Options” in terms of risk of loss of life, probability and duration of closure of the building after an earthquake, construction and post-earthquake repair costs HERE.
Since the structure is completely separated from the ground next to the isolator, the mechanical details (all connections such as electricity-water-waste-natural gas) should also be supported with special details to be suitable for earthquake insulation and movement in all directions. Such special applications are commercially available.
Due to the fact that the earthquake-proofed building is built in a way that it can move freely in all directions in the event of a possible earthquake, it will be completely separated from the ground and a space will remain around the structure. This gap must be crossed with all-round joints. Again, standard joints produced for such applications are easily available in the market.
Deprem yalıtım cihazlarının hiçbirinin tek başına depremin düşey bileşenine karşı bir etkisi yoktur. Düşey depreme karşı ekstra bir önlem alınmak isteniyorsa, deprem izolatörünün yanında ekstra özel sönümleyici sistemler kullanılması zorunludur. Bir diğer yandan da depremlerin düşey bileşenleri gerek yapısal gerekse yapısal olmayan elemanlar üzerindeki etkileri, yatay bileşenlere göre çok daha düşüktür. Bunu da göz önüne alarak, yapısal analizlerin sonucuna göre, düşey depreme karşı önlem alınıp alınmaması ihtiyacına karar verilir ve bunun sonucunda gerekmesi halinde ekstra özel cihazlar kullanılır.
In buildings planned to be built with earthquake isolators, the structure should be designed and modeled as insulator starting from the architecture. For example, the dimensions of the columns where the insulators will be placed should be adjusted with calculations and the general architecture should also be determined in accordance with the insulator application. Architectural approach and design in buildings with and without insulators are different from each other, and an insulator cannot be applied to an architecture that is planned and prepared without insulators. For this reason, a structure that is planned to be applied with an earthquake isolator should be solved with an appropriate architecture from the beginning. For example, in earthquake-proof buildings, it should be preferred to use square column and beamed frames instead of thin long column / curtain type carrier systems and non-beam slabs.
After the architectural solutions of the building are adjusted to be compatible with the earthquake isolator application, static calculations can be made more effectively. Similarly, static calculations should be made with structural analysis programs that have earthquake isolator models, have the capacity to perform linear and nonlinear analyzes and have proven themselves in this field.
Before starting the static calculations, the design acceleration spectra to be taken from the Turkey Earthquake Hazard Map published by AFAD, as well as site-specific earthquake hazard analyzes should be made by experts and the calculations of the structure in question should be started after that.
It is very important that the insulators are mounted to their respective places in the field by expert teams in this field. The assembly of these devices must be done very precisely and carefully. Otherwise, no matter how correct design and production is made, it is very difficult to reverse an error that will occur during assembly.
When earthquake insulation is applied to a building, it cannot be expected that a size or reinforcement savings will be achieved in the structural elements. In some cases, there may be savings such as reducing the size of the superstructure elements and reducing the amount of reinforcement, but this may vary for each structure and must be checked with calculations.
Earthquake insulation can be used not only in new constructions but also in reinforcement applications. However, beforehand, it is obligatory for an expert team to make an evaluation in order to understand whether the structure is suitable for earthquake insulation and retrofitting.
For more detailed information, you can check the "General Information" section.
Some examples for empowerment;
Marmara Başıbüyük EAH: https://www.youtube.com/watch?v=kb4myGiI5ws
Moda Apartment: https://www.youtube.com/watch?v=Zo1P-HZyyJs
There are basically 3 types of insulation devices used in the world to provide earthquake insulation: Friction pendulum type (FPB-TDP), lead core rubber type (LRB) and highly damped rubber type (HDRB).
The advantages of friction pendulum type earthquake insulation devices over their counterparts can be listed as follows.
It eliminates the torsion effect in buildings.
Smaller (thin) devices can be designed compared to alternatives.
It is suitable for design and application at very high and very low axial loads and displacements.
With theoretical calculations, its behavior in practice can be predicted very consistently.
It has high fire resistance compared to its alternatives.
It is longer lasting compared to its alternatives.
Material properties do not change during its lifetime and are maintenance-free.
You can find detailed information about our products HERE.
Earthquake insulated buildings fall into the category of “special construction”. In this context, T.C. The Ministry of Environment and Urbanization makes it mandatory to work with predetermined experts in the design and implementation stages of special buildings. According to this system called "Design Supervision (TGUA)", when it comes to an earthquake insulated structure, it is obligatory to work with design supervisors during the stages of both site-specific earthquake hazard analysis (TGUA-1) and designing the earthquake-proof structure (TGUA-5). Design supervisors are responsible for checking and approving the calculations made in the relevant areas.
Detailed information about the Design Supervision system, which has been specified as TGUA above, is available in the document titled "Communiqué on Design Supervision and Control Services to be Made within the Scope of the Turkish Building Earthquake Regulation" published in the Official Gazette dated 11.01.2019, you can find it HERE.
TDP earthquake isolators do not have a lifespan. Steel, stainless steel and Teflon-containing materials are used in TDP devices. In this way, it is maintenance-free and has a much longer life than reinforced concrete structures. The service life of TDP earthquake isolators is at least 100 years.
TDP devices do not need to be replaced after earthquakes, so they are not disposable. It will remain functional in all earthquakes that will occur during the life of the structure.
Periodic checks of earthquake isolators should be made. Control procedures determined specifically for the structure should be applied.
Earthquake isolators do not require maintenance under normal conditions.
The standard warranty period of TDP earthquake isolators is 15 years. Warranty periods may vary depending on the project.
Dimensions, dimensions and weights of TDP friction pendulum insulators are highly variable and are designed specifically for the project. The design of the insulators varies depending on many factors such as the weight of the superstructure, the vertical load on each insulator, the seismicity of the area where the building is located, the concrete class used in the building, the performance target of the building, and the architecture. Accordingly, earthquake isolators can be either 50 cm in diameter or 200 cm in diameter.
In New Buildings:
Insulator application is done in the following order in new constructions:
• Performing soil analysis.
• Site-specific earthquake hazard analysis, control and approval of the analysis by TGUA-1.
• Preparation of the architecture.
• Determination of TGUA-5 and getting approval for architecture before starting static calculations.
• Preparation of static projects with insulators and preliminary analysis.
• The isolator manufacturer's design of isolators according to preliminary static analyses, structural properties and seismicity (determination of insulator budgetary costs).
• Analyzing and checking the static project once again with the final isolator parameters, making corrections if necessary and finalizing the project. Obtaining TGUA-5 approval.
• Production and quality control tests (prototype and production tests) of insulators. With these tests, the design parameters of the insulators are verified.
• Installation of insulators on site.
• Completion of superstructure construction.
• The licensing and approval processes are also progressing at this time. This process, which was very problematic before 2018, has been facilitated by the publication of the new earthquake regulation and the earthquake insulation section in this regulation. In addition, the awareness of the systems in the sector has increased, especially with the applications that started with hospitals, and this has facilitated the approval processes.
Detailed information about the Design Supervision system, which has been specified as TGUA above, is available in the document titled "Communiqué on Design Supervision and Control Services to be Made within the Scope of the Turkish Building Earthquake Regulation" published in the Official Gazette dated 11.01.2019, you can find it HERE.
Things to consider for retrofit projects with insulators:
• It cannot be applied if the structure is adjacent or it should be applied to all adjacent structures at the same time.
• It is necessary to have an extra and empty floor where the isolator will be applied (warehouse, parking lot, etc.). Otherwise, the floor on which the insulator is placed will not be insulated.
• Although the building itself will not be touched and the occupants will not need to evacuate their belongings, the occupants of the building will not be required to be in the building while the works are being carried out on the foundation of the building (within the framework of OHS rules).
• On the floor where the insulator will be applied, it is very likely that the structural elements will need to be strengthened.
• In order to clearly understand whether the structure is suitable for reinforcement with insulators, an expert team must first see the structure, then the strength checks of the structural elements should be made and the preliminary analyzes should be carried out by creating the static model of the structure. The strength of the building, the way of sitting and its architecture affect this whole process.
• Except for these items, the processes written for the standard structure are valid.
There is no price list for TDP earthquake isolation devices. The reason for this is that insulators are specially designed for each project and their sizes vary according to many factors. The dimensions of the insulators, and therefore their prices, vary depending on many factors such as the weight of the superstructure, the vertical load on each insulator, the seismicity of the area where the building is located, the concrete class used in the building, the performance target of the building, and the architecture. After determining the seismicity of the region with the preliminary static results of the project, a budgetary cost study can be carried out and prices can be calculated.
Note: As a domestic manufacturer, after entering the market in 2016, earthquake isolators are now available in our country. Today, as TİS, we are able to carry out earthquake insulation applications on a turnkey basis and in accordance with all national/international specifications and regulations at prices that are half or even a quarter of the prices in 2015 and previous years, when we were not in the market yet. In addition, we can carry out the entire process of earthquake insulation (R&D, design, production, testing, assembly) in Turkey without any dependency on abroad. This process, whose design, production and tests were completely imported before 2015, became domestic with the establishment of our company TİS in 2015. First, the Ministry of Health published in 2013 and 2018 and «1. Earthquake insulation is important in civil engineering practices in Turkey with the circulars requiring that all hospitals with 100 beds or more be built with earthquake insulation in earthquake zones and 2nd degree earthquake zones, followed by the “Principles for the Design of Buildings Under the Impact of Earthquake” earthquake regulation that came into force in 2019. has come a long way.
At this point, the most important point to be considered is that the structures to which earthquake isolators are applied can continue to be used immediately after the earthquake. This means that the structural and non-structural damage that will occur after a possible earthquake is completely prevented and possible repair costs will not be experienced, and this is a performance that can never be achieved in a structure designed without insulators. For example, people living in a house designed with earthquake insulators and applied correctly will be able to continue to live in their homes even after the expected maximum magnitude earthquake in the region, and will not bear any repair costs or the psychological burden of the earthquake.
You can reach the effects of the earthquake insulation application during the first construction phase and after a possible design earthquake.
Earthquake insulation cannot be applied to adjacent structures.
It is not correct to apply earthquake insulation in structures that have the risk of liquefaction.
It is not correct to apply earthquake insulation alone in very high and tower type structures (12-13 floors and above). In this type of structures, applications should be done with extra damping devices.
Reinforcement projects begin with expert teams examining the existing structure and determining whether it is suitable for earthquake isolation and retrofitting.
All projects that are considered to apply earthquake insulation should start the project by consulting experts on the relevant subject beforehand.
Our company TIS Technological Isolator Systems, which was established in Ankara Kazan in 2014 and is located in a factory area with 50.000 m2 closed and 200.000 m2 open area, is the first and only domestic company that produces friction pendulum type earthquake isolator (TDP) in Turkey and is the only one in the world. is among the few companies that make this production. Starting from R&D and design, we produce turnkey projects that offer all of the after-sales services along with production, testing and field assembly.
Our company has its own patented product as well as an integrated management system consisting of ISO 9001, ISO 14001 and ISO 45001. In addition, it has CE certificate for all its products and can produce in accordance with all national / international standards and specifications. In addition, our company has the only European Technical Approval (ETA) certificate in the world for friction pendulum earthquake isolators.
You can access our Documents and Certificates HERE.
We perform the tests of our products in independent and/or accredited laboratories, which are accepted in the world and have the capacity to perform earthquake isolator tests. The laboratories we have used so far are listed below:
Eucentre Laboratory (Pavia, Italy)
Caltrans SRMD Laboratory (San Diego, USA)
Esquake Laboratory (Eskişehir Technical University, Turkey)
Politecnico di Milano (Milan, Italy)
TİCEM Advanced Construction Technologies (Ankara, Turkey)