Seismic isolation system with suspended columns

Abstract

This invention is a system for isolating a structure from earthquakes with a suspended system. These suspended columns isolate the building from earthquake vibrations. Previous isolators against horizontal earthquakes have weaknesses and strengths, which this system has tried to overcome and have a good performance against the vertical acceleration of the earthquake. Also, previous isolators had a high production cost and were not widely used. In this system, a pendulum suspension mechanism was used to provide adequate performance against horizontal and vertical acceleration. The operating process of the isolator is that two separate pieces (tripods) are made and these two tripods, which are located inside each other, are connected to each other by a strong cable between these two elements, giving the isolator a pendulum suspension. Also, U-shaped elements have been incorporated into the system to create damping. These U-shaped parts are connected to the system by screws and can be replaced in a very short time, which makes the structure more resilient.

Description

Description of the invention Title of the invention (as stated in the declaration) Seismic isolation system with suspended columns. (Seismic isolation system with suspended columns) Technical background of the relevant invention The present invention is primarily related to civil engineering and specifically to the earthquake-resistant nature of structures. This invention is directly related to improving structural performance, reducing earthquake damage, and improving the resilience of structures, infrastructure, residential, office, commercial, and bridge buildings. This method also has special advantages in terms of economy, efficiency, and ease of implementation, which will contribute to the widespread use of this isolation system on a very large scale. Technical problem and stating the objectives of the invention Earthquakes are destructive natural events that occur in a fraction of a second due to the release of energy stored in the Earth's crust. These phenomena threaten human life, destroy property, and disrupt the functioning of social life for some time after the event. Therefore, to ensure human safety and health, it is necessary to reduce the risks of earthquakes by examining the behavior and performance of structural and non-structural components, vital arteries and highway structures, how these structures damage society and the resilience of society. These damages can be reduced more effectively through various methods (dampers and isolators). Seismic design of building structures is a common practice based on increasing the resistance capacity of the structures, for example by using shear walls, braced frames or earthquake-resistant frames. However, these traditional methods often lead to increased accelerations of upper floors for rigid buildings or large inter-floor drifts for soft buildings. Therefore, building equipment and non-structural components may suffer significant damage during a large earthquake, even if the structural components are not damaged significantly. This is not acceptable for structures where the equipment is more expensive and valuable than the buildings themselves. High-tech and high-precision manufacturing plants are examples of structures that have very expensive and sensitive equipment. In addition, hospitals, police and fire stations, and telecommunications centers are examples of places that have valuable equipment and important functions after an earthquake and must perform their duties immediately after an earthquake. To minimize drift between floors and reduce floor acceleration, the concept of seismic isolation is considered as an approach to seismic design of structures. Seismic isolation is a practical design strategy that is used for seismic retrofitting of existing buildings and in the design from the beginning. Seismic isolation can be created by installing special equipment (isolators) between the structure and the foundation to reduce the accelerations transmitted from the ground to the structure. The application of seismic isolation should not be limited to the isolation of the foundation and the structure on it, but it can also isolate sensitive equipment within the structure and on the floor of the floors from undesirable and excessive floor vibrations and prevent acceleration from being applied to that equipment and its failure. Conceptually, seismic isolation reduces the response of a structure to ground motion. Conventional isolation systems reduce the seismic forces transmitted to the structure by increasing the period of the structure and adding some damping. Another aspect of the isolation is the added damping to the structure, which is an inherent feature of most isolations. In some cases, additional energy dissipation devices are used at the isolation interface to increase damping. According to previous research, under conventional conditions, the seismic isolation system reduces the drift between floors in the structure to an acceptable extent (compared to what exists in the fixed support case). The floor accelerations in the structure are also significantly reduced. Although the extent of reduction depends on the behavioral characteristics of the isolators (force-displacement) (depending on the type of isolator). Reducing the drift in the superstructure protects structural and non-structural components from earthquake damage and reduces losses. Acceleration reduction protects non-structural components that are sensitive to acceleration, such as motion-sensitive equipment, machinery, and hardware, both of which are important factors in determining structural damage indices. Another design approach to improve earthquake response and damage control performance in structures is supplementary energy dissipation systems (dampers). In these systems, mechanical devices are embedded in the structural frames to dissipate energy throughout the entire height of the structure. Some energy dissipation systems, in addition to increasing the energy dissipation capacity of the structure, also increase strength and stiffness. Such systems include: yielding, frictional, and viscoelastic systems. Energy dissipation systems that use viscous dampers generally do not increase the strength or stiffness of the structure unless the excitation frequency is very high. In general, adding an energy dissipation system (dampers) results in reduced drift and thus reduced damage, but this can be associated with an increase in the total lateral force exerted on the structure due to the increased strength or stiffness. With additional energy dissipation systems (dampers), the structure cannot effectively reduce both interstory drift and storey accelerations, but seismic isolation allows the designer to do this simultaneously. In addition, seismic isolation reduces the lateral force (base shear) transmitted to the structure from the ground due to earthquake shocks, which is less achievable with energy dissipation systems (dampers). Seismic isolation systems and associated energy dissipators (dampers) are known as passive control systems because the control of the structure's movements is not controlled by an external force, but by a device designed at the base of the structure or within the structure. In addition to the passive control system, there are active and semi-active structural control techniques that are still under research and development for seismic retrofitting and retrofitting of structures. One of the weaknesses of active and semi-active control techniques is the relatively high cost of maintenance of the control system and actuators, which must be always active to respond to large earthquakes. There are semi-active and intermediate controls that try to use the positive features of passive and active control devices. Seismic isolation is a mature technology, having been in use for a long time, and is an effective means of protecting structures and equipment attached to them. There are a number of acceptable isolation systems, the construction of which is well understood, and each has its own advantages and disadvantages, which will be discussed below. Nevertheless, the concept seems to be of great interest to inventors and researchers, and new and different systems of separators are proposed and patented every year. Many of these new systems are impractical and have very impractical features to manufacture, but the number of such designs is increasing year by year. In general, there are two general solutions to deal with the destructive effects of earthquakes and reduce damage to structures: First way: Reinforcing structures The conventional seismic design method of structures is based on strength and increasing the resistance of the structure. This approach to strengthening structures aims to create lateral load-bearing capacity in the structure by increasing its strength and ensuring its ductility, and does not look at the locations of damage and their distribution and arrangement in the structure. Implementing this method increases the structural dimensions, connections and load-bearing elements, and consequently increases the cost. Lateral bracing members such as wind braces, shear walls or other stiffening members are used. Increasing the stiffness of the structure leads to the absorption of more force resulting from the earthquake and causes the dimensions of the structural members to increase, which increases the costs of constructing the structure. In addition, due to nonlinear deformations and the occurrence of damage and failure in structural and non-structural members due to the occurrence of displacements and high accelerations, financial and human losses are inevitable. Second way: Reducers of seismic energy input to structures The idea of ​​designing a structure based on reducing the earthquake force by preventing its energy from entering the structure is one of the solutions. This idea has been used in many cases in the design and implementation of important structures in recent years. According to analytical and experimental results, structures equipped with this technology will have a lower seismic response than conventional structures, and the main period of the structure will increase with the help of equipment placed between the superstructure and its substructure. The earthquake energy reduction systems that have been produced in the world so far, despite the fact that they reduce the earthquake force transmitted to the structure, make the skeleton lighter in design and reduce the costs of skeleton construction, due to the use of special technologies and exclusive production and the need for special expertise for the design, installation, and post-installation maintenance stages, the performance of the building depends on the specific technologies of these systems, and the high cost of using these systems outweighs the savings resulting from the lighter skeleton, and they have no economic advantage over conventional methods. For these reasons, the use of seismic reduction systems has generally been in developed countries and related to important and special structures and infrastructures. In developing countries such as Iran, which is considered a region with high seismicity, the use of these mitigation systems is not cost-effective and has not been implemented except in specific cases and structures, which is one of the weaknesses of these existing tools.Elastomeric isolators do not have high capabilities due to their geometric limitations, as these isolators have limited ability to deform. This problem does not exist in pendulum isolators, but in these isolators, since a metal ball is used and the tension at the top and bottom of the ball is high, there is a possibility of crushing and high uncertainties have been seen in this type of isolators. Although these problems do not exist in rail isolators, in these isolators, permanent displacements occur after an earthquake and the structure must be returned to its original location, which causes secondary problems after the earthquake. Friction isolators and other cases are only capable of being isolated in specific directions, and in some cases, when these shortcomings are overcome, the construction and maintenance of these isolators is very difficult. Another weakness in all these isolators is the excessive transfer of vertical acceleration to the structure, which in structures near the fault causes undesirable behavior in the structure and the isolator. Since the manufacture of isolators usually requires advanced technology, they are manufactured exclusively abroad by a few companies, and this, due to sanctions and high costs, disrupts the supply and expansion of these isolators and prevents their expansion. A new isolator system has been proposed in this design, in addition to its appropriate performance in seismic isolation (reducing horizontal and vertical acceleration of earthquakes), which, while improving the performance in vibration response, also has the property of reversibility after an earthquake, has the ability to be produced in domestic workshops at a much lower cost than foreign models. The present invention, in view of having all the advantages of isolators, also causes a significant reduction in the vertical accelerations of the structure, which, considering the presence of most of the densely populated cities of the country in areas near the fault, causes a reduction in the vertical acceleration of the structure. Among other things, the lack of permanent displacement (return to the initial state) increases resilience and better performance than other isolators. A description of the state of the prior art and the history of developments related to the claimed invention. Existing passive seismic isolation systems can be classified into four main groups: (1) elastic isolators, (2) rolling-based, (3) elastomeric, and (4) sliding-based isolators. Elastic isolators provide sufficient horizontal flexibility, but are accompanied by softness in the vertical direction. In addition, they lack damping mechanisms and efficient return to the initial state (centripetal force). Rolling isolators provide unparalleled horizontal flexibility and softness, but require damping, centripetal force mechanisms, and sufficient vertical load-bearing capacity. In addition, they have no wind resistance. Elastomeric isolators offer high vertical stiffness for heavy structures, combined with horizontal flexibility and softness. However, some design constraints must be observed to avoid pi-delta and heave effects in the isolators. The slip-based isolator, called the friction pendulum system (FPS), can overcome most of the aforementioned drawbacks, but unfortunately, due to the uplift of the structure, the variable coefficient of friction, and the constant period of oscillation, it has many difficulties for seismic design, construction, and maintenance [3]. The separation systems mentioned above are based on well-known and accepted physical principles, but none of these devices is perfect and flawless because each has its own functional and structural weaknesses. These shortcomings have led to attempts to enhance existing devices or to innovate in the construction of new devices, with the aim of achieving the maximum level of protection of structural and non-structural components. Unfortunately, most of the isolation systems reported in the technical literature are patented products, which makes it difficult for researchers to obtain information on the construction, materials used, and important aspects of the construction of these devices, which is also true for most newly invented products. This has made the development and improvement of the application of each of these isolators a difficult challenge for researchers. Therefore, researchers and inventors are moving towards new methods for seismic isolation, which leads them away from practical and feasible designs that can be manufactured and have good performance. To examine the historical and past work done in the field of seismic isolation, one can look at the use of structural isolation in past centuries. According to available reports, the first signs of the use of this type of system against earthquakes were observed in Pasargadae, a city in ancient Iran, and in the sixth century BC. This system consists of a deep and wide stone foundation and smooth mortar, which is placed on another foundation of smooth and wide stone. These two foundations are connected in such a way that the structure remains intact during earthquakes. The first seismic isolation system was proposed by Kawai in 1891 and was a structure with a monolithic foundation and several rows of orthogonal rollers. In August 1909, a doctor named Kalantarintz in a northern English town called Scarborough wrote a letter to the head of the Chilean Seismological Institute in Santiago, in which he introduced a new method for constructing earthquake-resistant buildings.According to his plan, buildings built in isolation could be used with complete safety in seismic areas, because the presence of free, lubricated joints reduced the intensity of the earthquake. In another letter he sent to the British Patent Office, he claimed that buildings built on these free joints and a layer of soft sand, mica, or talc would slide during an earthquake, reducing the force of the earthquake entering the structure and preventing the structure from collapsing. According to the documents provided, the first use of rubber isolators was in 1969 in a 3-story concrete elementary school building in Skopje, Yugoslavia, which was designed and built by a Swiss engineer and isolated with a system known as Swiss 3D full base isolation. The rubber blocks used in this school, unlike modern models today, were without any reinforcement and as a result had a large lateral expansion due to the weight of the building, which caused their weakness. Since the behavior of these rubbers in shear up to strains greater than 100% is completely linear, its damping is about 2 to 3% of the critical damping, therefore they do not perform well during earthquakes and cause excessive displacements of the superstructure and instability in the superstructure. In other words, these seats can only be used as seismic isolators if an additional damping system is placed next to them to provide the necessary damping. In 1954, Reinforced Rubber, which was made using thin steel sheets between layers of rubber, was invented by French engineer Freyssinet and patented in France. Reinforced rubber combines the vertical stiffness of the steel layers with the horizontal flexibility of the rubber. Since 1980, it has been used as a seismic isolator for structures in earthquake-prone areas. Recycled Tire Isolator In 2002, a method of seismic isolation of small residential buildings for countries and regions of the United States using recycled worn automobile tires filled with crushed stone and placed under the building was proposed by Lang and patented in the United States in 2005. Soil and Tire Isolator In 2007, a seismic isolation method for developing countries using a mixture of soil and recycled automobile tires was proposed by Tsang. Despite the advantage of increasing soil damping by adding worn tires, the high thickness of the isolation layer of about 10 to 20 meters, despite regulatory restrictions and a large protrusion of 10 meters from each side of the building, has made the use of this system impractical. Several roller isolators have been proposed by various researchers, including the system proposed by Guerreiro et al. Their proposed system consists of steel balls placed on steel plates. Ismail et al. (PCT patent (WO2010 / 000897) and ES 2551182A1))) have also proposed a new roller isolator system. Although the isolator systems using rolling balls between the seating plates perform well in reducing the excitation transmitted to the isolated structure, they have a much lower load capacity and cannot be used for isolating buildings. Also, crushing and scratching of the system components are among the problems of these systems. Systems using a rolling rod placed between inclined plates have been proposed, including the separator system proposed by Tsai et al. This system consists of a rolling rod placed between U-shaped plates.The main problems of this system include the sudden impact when the rolling rod passes through the center of the base plates and the lack of continuity of the parts against the vertical forces of the earthquake. Hosseini and his colleagues have also proposed the idea of ​​separation using a pair of rolling rods placed between the curved plates. Although this system has succeeded in solving the problem of impact when the rolling rod moves on the base plates, there is still the problem of separation of the system components under the vertical force of the earthquake in this system. Various methods have been proposed to dissipate the horizontal force, including viscous, frictional or yielding dampers, which each inventor has addressed. ((CN 107327193) and CN 204224979) and (US10,443,677B2) and (US 2022 / 0106804A1)). But Dr. Robinson solved the problem by placing lead inside the supports in the form of an LRB, so that the bilinear softening behavior of the LRB shows that this isolator is initially relatively stiff and has a short effective period of oscillation, and with increasing earthquake force, the rubber isolators with a lead core become softer and increase the oscillation time. In general, the dynamic behavior of the LRB seismic isolator system is nonlinear (bilinear). In nonlinear systems, especially LRB, as the system passes the yield point and moves in the post-yield part, the area under the graph suddenly increases more, so that a lot of energy is dissipated through the hysteresis loops formed. Lead in the LRB seismic isolator system has two main functions, both of which result from the plastic deformation of the lead core. First, it causes the curve of the structure to change in a way that ultimately leads to an increase in the period of the structure, and second, the hysteretic properties and inelastic deformation of lead cause an increase in the damping value of the structure, which is a weak point that also causes permanent displacements.Changes in the force-displacement curve based on the vertical load on the LRB, which must be considered in determining the vertical load on the support, the combination of dead load, live load and seismic load. Therefore, light structures that have little vertical load face the problem of LRB performance. Also, in cases where a large vertical acceleration is applied to the structure, a large force is applied to the LRB, which causes its destruction. Therefore, paying attention to the vertical force applied to the LRB isolator is of particular importance. Considering the above-mentioned cases, since Robinson Company is the inventor and pioneer of seismic isolator technology in the world, it has considered it its duty to solve this problem as well. As a result, Robinson introduced two products called Ro-Glider in 2007, which are friction isolators. A brief overview of the general grouping of basic seismic isolators: Elastomeric separators: made of rubber or neoprene with lead core and without lead core, friction-sliding separators with a sliding surface made of Teflon or stainless steel, or a combination of them. Base seismic isolators are highly rigid in the vertical direction and fully flexible in the horizontal direction. They are made of reinforced rubber (thin layers of high-resistance rubber (HDR) reinforced with steel sheets). They are capable of withstanding the gravity loads of the building in the vertical direction and of absorbing vibrations caused by earthquakes in the horizontal direction. To ensure the proper functioning of the isolation system and maintain the safety of the structure, control, maintenance, and inspection of seismic isolation devices must be carried out sequentially by the inspection and quality control system and specialized engineers. Design and implementation problems and issues Specialized and continuous maintenance and inspections of the separation system Increasing the cost of using these systems Reduced acceleration component in the horizontal direction and low impact in the vertical direction Naeim, Farzad and JMKelly. Design of isolated seismic structures: from theory to practice. John Wiley & Sons; 1999. Skinner RI, Robinson WH, McVerry GH. An introduction to seismic isolationJohn Wiley and Sons. New York Search In 1993. Murnal P, Sinha R. Aseismic design of structure–equipment systems using variable frequency pendulum isolator. Nuclear Engineering and Design 2004;231:129–39. Botis M, Harbic C. A brief history upon seismic isolating systems. Bulletin of the Transilvania University of Brasov Engineering Sciences Series I 2012;5:93. Housner Gw, Bergman LA, Caughey TK, Chassiakos AG, Claus RO, Masri SF, et al. Structural control: past, present, and future. J Eng Mech 1997;123:897–971. Guerreiro L., Azevedo J., Muhr A.H., 2007, Seismic Tests and Numerical Modeling Of a Rolling-ball Isolation System, Journal of Earthquake Engineering . Ismail M., Rodellar J., Ikhouane F., 2009, Performance Of Structure Equipment Systems With a Novel Roll-n-Cage Isolation Bearing, Computers and Structures . Tsai M., Chang K., Wu S., 2006, Seismic Isolation of a Scaled Bridge Model Using Rolling Type Bearings, 4 th International Conference on Earthquake Engineering Hosseini M. and Kangerloo K., 2007, Investigation of a seismic isolator in the form of orthogonal rollers, Fifth International Conference on Seismology and Earthquake Engineering Frictional pendulum isolation system based on spherical concave foundations for short-range structures. Application number: 13915014000304090 Sliding-pendulum foundations with very high frequency performance for protecting various structures against earthquakes. Application number: 13915014000306979 Pendulum column as a seismic isolator Application number: 139350140003003582 Sliding pendulum isolator Google patents, KR20120128523A, pub. date: 2012-11-27 Suspended low-frequency horizontal pendulum isolator for vibration isolation systems Google patents, US5779010A, pub. date: 1998-07-14 Pendulum type vibration isolator Patent Scope, JP2022035739, pub. date: 2022-03-04 Sliding pendulum seismic isolator Patent Scope, US20100095608, pub. date: 2010-04-22 Providing a solution to an existing technical problem along with an accurate, sufficient, and integrated description of the invention Designing a structure based on reducing earthquake forces by reducing energy input to the structure is one of the solutions. According to analytical and experimental results, structures equipped with this technology will have a lower seismic response (especially drift) than conventional structures (fixed base), and the main periodic period of the structure will be increased with the help of equipment placed between the superstructure and its substructure (isolator). The use of special and exclusive technologies requires special expertise for the design, installation, and post-installation maintenance stages, and makes the building's performance dependent on special technologies. The high cost of using these systems outweighs the savings from lighter skeletons, and they have no economic advantage over conventional methods. For these reasons, the use of seismic reduction systems (isolators) has generally been in developed countries and related to important and special structures and infrastructures (hospitals and sensitive centers). In developing countries such as Iran, which is considered one of the regions with high seismicity, the use of these reduction systems has not been cost-effective and has not been implemented except in special cases and structures, which is one of the weaknesses of these existing tools. Elastomeric isolators do not have high capabilities due to their geometric limitations, because these isolators have limited ability to deform.This problem does not exist in pendulum isolators, but in these isolators, since a metal ball is used and the tension at the top and bottom of the ball is high, there is a possibility of crushing and high uncertainties have been seen in this type of isolators. Although these problems do not exist in rail isolators, in these isolators, permanent displacements occur after an earthquake and the structure must be returned to its original location, which in itself causes secondary problems after an earthquake. Friction isolators and other similar cases are only capable of being isolated in specific directions, and in some cases, when these shortcomings are overcome, the construction and maintenance of these isolators is very difficult. Another weakness that exists in all of these isolators is the very high transfer of vertical acceleration to the structure, which in structures near the fault causes undesirable behavior in the structure and the isolator.Since the manufacture of isolators usually requires advanced technology, they are manufactured exclusively abroad by a few companies, and this, due to sanctions and high costs, disrupts the supply and expansion of these isolators and prevents their expansion. A new isolator system has been proposed in this design, in addition to its proper performance in seismic isolation (reducing horizontal and vertical acceleration of earthquakes), which, while improving the performance in vibration response, also has the property of reversibility after an earthquake, has the ability to be produced in domestic workshops at a much lower cost than foreign models. The presented pendulum isolator, considering all the advantages of isolators, also causes a significant reduction in the vertical accelerations of the structure. Considering that most of the densely populated cities of the country are in areas near faults (Tehran, Mashhad, Tabriz, etc.), it causes a reduction in the horizontal acceleration of the structure. Among other things, it can be mentioned that there is no permanent displacement (return to the initial state), which increases resilience and better performance than other isolators. The overall view of the system can be seen in Figure (4), which is in three dimensions. The operating process of the separator is as follows: two separate pieces (tripods) are made (piece 2 in different views of the figures) and then placed inside each other according to figures (1) and (3) but do not touch each other. Then, the upper and lower plates are installed on the tripods (piece number 1 in the figures). For access in the next steps, holes have been made in the plates in advance. These two tripods, which are located inside each other, are connected to each other with a strong cable between these two elements (piece 4 in the figures) and give the separator a suspended state. The upper plate is installed under the building structure or the upper columns, and the lower plate is installed on the foundation of the structures (the connection of the plates to the foundation and columns is rigid). After these parts are manufactured and installed, the U-shaped elements are connected to the isolation tripods (part 3 in the figures) to deform in very severe earthquakes, damping the incoming earthquake energy. Seals are provided for the installation of these parts (parts 5 and 6). A nut (part 6) is provided for connecting the cable in the middle of the tripods.For the freedom of action of the isolator in small earthquakes, circular holes are provided inside the U-shaped elements so that the U-shaped elements are not used in small displacements of about 2 cm and do not prevent low-amplitude movements. These U-shaped elements can be replaced after severe earthquakes or smart materials such as (SMA) can be used, which after yielding with very simple processes, their residual stress is eliminated. The shear bars (piece 7 in the figures) are intended for complete and non-slip connection. Therefore, in general, the behavioral performance of the isolator has been suspended or pendulum. So in summary, according to the figures and drawings, two separate pieces are connected to each other by cables in such a way that the structure is suspended (separated) from the ground, so that due to the displacement and acceleration of the ground, this structure can easily change shape in the isolator part and transfer very little energy to the structure. It will also have much, much less maintenance problems than other isolators. The highlights of this isolator are better performance, easier construction, easier maintenance and most importantly, the very high resilience of this isolator system in earthquakes. Explanation of shapes, maps and diagrams This section briefly describes the items in the "Map" file. Part 1) Circular plate with hole Piece 2) Tripods Part 3) U-shaped element Piece 4) Strong cable Piece 5) Small bead Piece 6) Large nut Part 7) Cutter Piece 8) Foundation Piece 9) First floor beam Piece 10) Column on suspended column Piece 11) Creating holes for freedom of movement in different directions Part 1 is a steel plate made of locally available materials, with a circular hole for access and connection of the parts. Part 2 is a strong tripod made of steel to apply the forces acting on the plate to the strong cable in the middle of the tripod and to bring pendulum behavior to the isolator. Part 3, which is a U-shaped element, three at the top and three at the bottom, is connected to the tripod and the circular plate. This element creates damping by changing its shape. In the connection of the U-shaped element to the plate, a hole is created in the element to allow the structure to move up to 2 centimeters in each direction, and after 2 centimeters of movement, it creates additional damping to the system. Part 4 is a strong cable made of tow wires that are very strong in tensile stresses. This cable is placed between the two tripod elements in the form of tendons that can withstand a large tensile force. This type of material was used in this part because of its high tensile strength. Parts 5 and 6 are the small and large nuts for connecting and assembling the system.Part 7 is a rebar for shear transfer and connection of circular plates to the foundation. This element is also used for connection to the superstructure. In order to use U-shaped elements in large deformations and severe earthquakes, a hole is created in the U-shaped element to allow free movement of about 2 cm in each direction and then engages with the U-shaped element by creating a tab and increasing the damping by changing the shape of the U-shaped element to the system. (Figure 7). The above can be seen in Figure (1) front view, Figure (2) top view, Figure (3) side view, Figure (4) 3D view, Figure (5) 3D view of the tripod as a single unit, and Figure (6) the location of the suspended column system in the building, for a better understanding of the subject. A clear and precise statement of the advantages of the claimed invention over prior inventions. The main advantages of this separator can be listed as follows: 1-Reducing the energy input to the structure due to earthquakes 2- Lack of permanent displacement 3-Reducing the horizontal acceleration of the earthquake to the structure 4-High resilience compared to other separators 5- Easier to build and no need for special equipment 6- Ability to be mass produced due to its low cost Description of at least one implementation method for implementing the invention To implement this invention, like other isolators, for example, after the foundation is laid, points are considered according to calculations for the placement of the structural isolators, and the isolators are placed on them, and the structural elements are implemented on the isolators according to the plan, which adds the previously mentioned benefits to the constructed structure (less damage, greater resilience, and reduced costs). Explicit mention of the industrial application of the invention Applications of this invention include its use in the construction industry, infrastructure structures and bridges. For its implementation and according to the mentioned details according to the executive drawings prepared for the structure, the mentioned advantages of this separator can be achieved. Brief description of the invention This invention is a structural isolation system against earthquakes with a suspended system. These suspended columns isolate the building from earthquake vibrations. Previous isolators against horizontal earthquakes have weaknesses and strengths, and this system has tried to overcome these weaknesses and have a good performance against the vertical acceleration of the earthquake. Also, previous isolators had a high production cost and could not be widely used. In this system, a pendulum suspension mechanism was used to have a good performance against horizontal and vertical acceleration. The operation process of the isolator is that two separate pieces (tripods) are made and these two tripods, which are located inside each other, are connected to each other with the strong cable between these two elements, giving the isolator a pendulum suspension state. Also, U-shaped elements are embedded in the system to create damping. These U-shaped parts are connected to the system by screws and can be replaced in a very short time, which makes the structure resilient. Explanation of shapes, maps and diagrams Figure 1) Front view of the pendulum suspended column system Figure 2) Top view of the pendulum suspended column system Figure 3) Side view of the pendulum suspended column system Figure 4) 3D view of the pendulum suspended column system Figure 5) 3D view of the tripod as a single unit Figure 6) Front view of the system placement in the building Figure 7) 3D view of the hole in the U-shaped element for freedom of movement at low displacements

Claims

Claims What is claimed: Claim 1) What is claimed is a suspended column system used for buildings and infrastructure structures such as bridges. This system is described as a seismic isolation system with suspended columns. Claim 2) According to claim number 1, in the "suspended column seismic isolation system", the reduction and dissipation of earthquake input energy is achieved by using the suspended pendulum motion of the system and the nonlinear capacity of the materials (U-shaped). The cable used between the two tripods is in tension and allows equal freedom of movement in different directions. Claim 3) According to claim number 2, in the geometry of this system, due to the use of cables and the lack of bending and torsional stiffness, when acceleration is applied to the system, little acceleration is transferred to the structure. Also, due to the mass of the structure and the lack of horizontal stiffness (when replacing the U-shaped element), the system will move to the stable point of pendulum motion due to its weight and will have zero permanent displacement (centripetalism). Claim 4) According to claim number 2, the U-shaped element increases the damping of the system due to the deformation caused by large displacements under severe earthquakes. Creating a hole in the U-shaped element so that, at limited displacements (about 2 centimeters in all directions), the system does not have the initial stiffness due to the U-shaped element.

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