WO2020240260A1

WO2020240260A1 - Seesaw structural systems for seismic low-rise buildings

Info

Publication number: WO2020240260A1
Application number: PCT/IB2019/054464
Authority: WO
Inventors: Seyed Sasan ALAVI SHIRKHORSHIDI; Mahmood HOSSEINI
Original assignee: Alavi Shirkhorshidi Seyed Sasan; Hosseini Mahmood
Priority date: 2019-05-30
Filing date: 2019-05-30
Publication date: 2020-12-03

Abstract

Seesaw Structural System (SSS) is used for a-seismic low-rise buildings by using a Specific Central "Semi-Sphere and Bowl" mega support and Modified MTYPED Devices, which are, respectively, located at the center of building's foundation and the foundations of the peripheral columns of the building. By creating seesaw structural motion and reducing the force imposed by earthquake to the building, the SSS prevents serious damage to the building during the earthquake and absorbs the input energy of the earthquake. By placing the mega support, on which a relatively stiff truss for supporting the building superstructure is located, and by placing the fuses under the peripheral columns, the motion of the building is changed from the shear type during the earthquake to seesaw structural behavior. The fuses in the peripheral foundations consist of steel plates with specific trapezoidal shape (varying width).

Description

Seesaw Structural System for A-seismic Low-rise Buildings by Using Specific Central "Semi-Sphere and Bowl Mega Support" (SSBMS) and Modified MTYPED (MMTYPED) Devices

Seesaw Structural System (SSS) is used for aseismic low-rise luildings by using a Specific Central "Semi-Sphere and Bowl" mega support and Modified MTYPED Devices, which are, respectively, located at the center of building's foundation and the foundations of the peripheral columns of the building. By creating seesaw structural motion and reducing the force imposed by earthquake to the building, the SSS prevents serious damage to the building during the earthquake and absorbs the input energy of the earthquake. By placing the mega support, on which a relatively stiff truss for supporting the building superstructure is located, and by placing the fuses under the peripheral columns, the motion of the building is changed from the shear type during the earthquake to seesaw structural behavior. The fuses in the peripheral foundations consist of steel plates with specific trapezoidal shape (varying width).

The present invention relates generally to Earthquake Engineering, Structural Earthquake Engineering, Seismic Response Reduction, Innovative Seismic Design and H02B1/54 Anti-seismic devices or installations .

Description or the related art including information disclosed . examples of such assemblies are disclosed in the following pat. Nos.:

Earthquake Resistant Building Foundation, United States Patent Application 20080098670

An earthquake resistant building foundation is presented consisting of a receptacle having a series of slits each for slidably receiving a shaft, one or more springs located below the receptacle for buffering a vertical force, and a number of springs engaged with the shafts for lateral buffering purposes. A number of lateral buffering devices are connected to the shafts and each has a casing secured to the shaft, a cover slidably engaged onto the casing, and one or more springs engaged between the casing and the cover for buffering between the casing and the cover to form a two-stage compressing or buffering structure.

Structural Yielding Fuse, United States Patent 9915078

A yielding fuse to be used in a brace assembly, including a part to be connected at one end to a side of a brace member, and a second part to be connected at one end to another side of the brace member. These two parts are positioned such that to be disposed on opposite sides of the brace member along its axis. Each of these two bodies further includes a base displaced from the axis, a plurality of yielding arms extending from the base towards the axis and at least a first connecting plate, which rigidly connects the first part to the second part.

Force Limiter and Energy Dissipater, WIPO Patent Application WO/2018/150234

An earthquake force limiter and energy dissipater for using in racks or buildings. The device allows stable yielding of a flexural plate to enable controlling structures to form a stable cycling high displacement elasto-plastic mechanism against seismic ground motion. The flexural yielding of the plates limits the forces amount developed within the control structure of which the plates are part of; or within a standard structural frame. . The design reduces tensile or compressive membrane forces developing in the plate of the device; so that the plate can create a stable constant resistance while yielding to high lateral displacements.

Seismic Isolators , United States Patent 6160864

A seismic load reducing system for a nuclear reactor that decreases the seismic input to the internal components of the reactor, including the fuel is proposed. The system includes a set of seismic isolators positioned circumferentially between the reactor pedestal and a lower pedestal and a set of displacement limiters coupled to a lower pedestal skirt. The seismic isolators include a set of alternating layers of a resilient material and steel plates bonded together. Each displacement limiter includes a cantilever beam, which includes a core and two steel plates laminated on outer surfaces of the core. The steel plates are made of carbon steel having a yielding strength lower than the beam core.

Title: Earthquake-Proof Building Structure , United States Patent 3916578

An earthquake-proof building structure is consisted of a heavy, rounded base whose bottom center point rests on the special footing, and an upper hollow shell which is joined at its lower edge to the base. The weight of the base in relation to that of the shell is such that the center of gravity of the whole building structure locates within the base and beneath the shell.

Dissipator , WIPO Patent Application WO/2015/110497

A dissipater between ground and structures, which comprises a supporting base, fixed to the ground, and supports a contact base that can be associated, by a kind of kinematic connections, with a supporting structure, provided between the contact base and the supporting base and being adapted to allow the contact base motion with respect to the supporting base at least along two horizontal directions. There is also a control tool, which acts between the supporting base and the contact base, and is adapted to control the movement of the supporting base relative to the contact base. The dissipater comprises at least one rod-like energy dissipater that acts between the ground and the supporting structure.

Earthquake Isolator , United States Patent 10125510

The proposed isolator eliminate torsional effects due to earthquake forces affecting the building. It is placed between foundation and structure, and reduces the impact of earthquakes on structures. Thus, earthquake damage to load bearing elements of the building is eliminated.

Earthquake Insulating Building Structure , United States Patent 4707956

The proposed earthquake-insulating building structure includes a structure body and a supporting foundation having a plurality of earthquake-insulating piles embedded within the ground. Each of the piles has upper and lower portions. The upper portion is connected to the structure and a cylindrical casing surrounding the upper portion of the pile to create a space between the upper portion of the pile and the ground.

Earthquake-Proof Shoe for Bridges , United States Patent 4363149

A receiving plate for opposite ends of an upper shoe is placed between claws at opposite ends of a lower shoe. The rubber packings are detachably provided in the gaps between the respective claws and the receiving plate. Each packing consists of an inner plate, a first buffer rubber layer, a middle plate, a second buffer rubber layer and an outer plate. The first buffer rubber layer is made of two flat rubber plates with a plurality of rubber truss plates connected between in a zig-zag form to create a large number of voids within the first buffer rubber layer. Hence, the earthquake impact force is absorbed by the rubber packing for prevention of the receiving plate or the claws.

Earthquake Guarding System , United States Patent 4166344

An earthquake - resistant structure is proposed that permits limited displacement between the structure and the ground. It comprises support means and connecting means. The support means resists in elastic range to movement of the structure and the connecting means provides a fragile link between the structure and the ground, which breaks when the earthquake intensity reaches a specific level.

Earthquake Proof Building System , WIPO Patent Application WO/2014/092663

This invention, which is applicable to all kinds of buildings, eliminates the destructive effect of the earthquake in medium or severe intensity earthquakes by damping the earthquake forces within two foundation structures. The two foundations move independently in impact cantilevers before the earthquake forces acting on the building are transferred from the foundation to the upper floors. They comprise a fixed foundation which enables the building to hold on the ground, and a movable foundation which moves on the fixed foundation. There is also a foundation cantilever of the moving foundation, an impact cantilever, an earthquake wedge, which dampens a portion of the input energy during the impact of the foundation cantilever to the impact cantilever (4). The movement mechanism between the fixed foundation and the moving one is combined with the action of tension piles which are the structural elements, preventing the structure connected from toppling.

Earthquake-Resistant Reinforcement Assembly , United States Patent 9601220

An earthquake-resistant reinforcement assembly according to one embodiment of the present invention comprises: a rod of which one end is hinge-coupled to an upper structure; a combination pin which is formed at the other end of the rod and is extended to diametrically cross the rod; and a bracket which is provided on a partition wall of a nuclear reactor containment building and is coupled with the other end, wherein the bracket can withstand a tensile load and a torsional load by including first and second members which face each other and are extended in parallel to load the rod thereon, and groove portions which are formed at the first and second members to be coupled with the combination pin to form the shape of a double bracket.

Earthquake isolation floor , United States Patent 4402483

An earthquake isolation floor comprises a horizontal plate-like support frame having a generally circular or polygonal configuration, a support frame having a horizontal surface with a similar configuration to that of the fundamental frame in a plan view, but of relatively smaller dimensions, a number of horizontal springs disposed radially between the fundamental and support frames with each of the springs being kept in a preset state, and a number of horizontal dampers disposed radially between the fundamental and the support frames, whereby machinery and tools, etc. to be protected against vibration such as caused by an earthquake are adapted to be mounted on the support frame.

Earthquake Resistant Multi-Story Building , United States Patent 5271197

The present invention provides an earthquake resistant multi-story building which is characterized by having an energy concentration story. The energy concentration story has an elasto-plastic force-displacement relationship regarding horizontal force and displacement. The force-displacement relationship is characterized in that: (a) stiffness in elastic range (Fy /dy) is generally equal to an optimal stiffness of the same story according to an elastic design concept; (b) the yield strength Fy is generally less than 80% of an optimum yield strength; (c) stiffness in plastic range is positive and generally less than about a half of the stiffness in the elastic range; and (d) ultimate displacement is generally at least twice as large as the yield displacement. The energy concentration story is capable of entering into the plastic range while other stories are in the elastic range, and absorbing vibration energy by plastic deformations thereof so as to decrease deformations of other stories when a large external force is exerted to the building.

Earthquake Protective Column Support , United States Patent 4644714

A column support for buildings is presented which protects the building from potentially damaging earthquake ground motions. In each of these column supports the weight of the building is supported by an articulated slider that may slide translationally on an underlying concave spherical surface. The pivot point of the articulated slider is substantially near to the interface of the slider and concave surface. The slider is inherently stable for all dynamic loadings, provides reliable hysteretic friction damping, and can support high loads. A highly effective support is achieved, with small amplitude pendulum motions of the support which function to absorb severe earthquakes.

Earthquake-Proof Damper, and Earthquake-Proof System Using Same , WIPO Patent Application WO/2012/141378

The present invention relates to an earthquake-proof damper and to an earthquake-proof system using same. The earthquake-proof damper comprises: a first and second fixing member, each of which is fixed to an object to be installed; an oil damper installed between the first and second fixing members so as to absorb earthquake energy using the oil filled therein; and a spring cylinder installed between the first and second fixing members, and having a spring installed therein for absorbing earthquake energy by means of a cylinder capable of being compressed and extended. According to the present invention, it is easy to configure a system suitable for earthquake-proofing in accordance with the displacement between the stories of a building, customized design according to loads is convenient, earthquake-proofing efficiency can be increased, and economical installation and maintenance are possible as replacement and modification costs are low.

The system consists of two members that, in the event of a breakdown or fracture, a member starts to work after another member, while the proposed design is a seesaw system for low-rise buildings. Using the central support and modified MTYPED devices, it is located in the center of the building foundations and peripheral foundations of the building, respectively, and, by creating seesaw structural motion and reducing the force caused by earthquake to the building, prevents serious damage to the building during the earthquake and absorbs the input energy of the earthquake.

This summary is intended to provide an overview of the subject matter of the present disclosure, and is not intended to identify essential elements or key elements of the subject matter, nor is it intended to be used to determine the scope of the claimed implementations. The proper scope of the present disclosure may be ascertained from the claims set forth below in view of the detailed description below and the drawings.

In one general aspect, the present disclosure describes Seesaw Structural System for A-seismic Low-rise Buildings by Using Specific Central "Semi-Sphere and Bowl" Support and Modified MTYPED Devices In the technical field of FIXED CONSTRUCTIONS (E) HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL-SHIFTING .

Although seismic design codes regulations attempt to prevent the collapse of buildings, they accept heavy damages to structures in severe earthquakes. These regulations will result in undesirable consequences, especially in populated cities, including: loss of residence or work place of many people for a long time, very difficult and time consuming demolition of damaged buildings, troublesome and cost and time consuming process of the disposal of debris caused by the destruction of the heavily damaged buildings. The repairable design of buildings using the idea of "damage direction", which is meant to direct the damage caused by the earthquake to certain parts of the structure as energy absorbers (fuses), so that the main components of the structure remain intact is a very effective way for avoiding the aforementioned adverse consequences. The device is installed in structures and dissipates the energy imposed to the structure during the earthquake. Hence, by placing these fuses in the peripheral and central foundations of the building, it controls the way it moves during an earthquake and guides the destructive energy imposed by the earthquake to the building towards the fuses. Using this device, the drifts of the building’s floors during its swaying is significantly reduced. Seesaw Structural System is used for Aseismic Low-rise Buildings by Using Specific Central "Semi-Sphere and Bowl" Support and Modified MTYPED Devices is, respectively, located in the center of building's foundations and the foundations of the peripheral columns of the building, and by creating seesaw structural motion and reducing the seismic forces acting on the building, prevents serious damage to the building during the earthquake and absorbs the input energy of the earthquake. The system reduces around 80% of the damage to the structural elements as well as non-structural components of the building.

Design of buildings in such a way that they can be repaired after severe earthquakes has been taken into consideration in recent years. One of the ways to achieve this goal is the idea of damage direction by using specific structural fuses in the structure. The proposed structural fuse in this invention consists of tapered yielding steel plates, as damper or energy dissipater. The features of the proposed fuse include:

Ease of manufacturing by using simple steel shop machineries

Potential of fast and easy installation without the need to advanced equipment

Accessibility and possibility of easy replacement of yielding steel plates in case of being damaged, especially after severe earthquakes (in fact, the previous energy dissipating devices have all been used either in diagonal bracing elements or between bracings and other structural members, while the proposed device is used at the bottom of columns at the ground level.)

Possibility to adjust the stiffness and strength for different levels of loading in various structures, including multi-storey buildings, industrial towers, etc.

The variability of the number of yielding steel plates used in the fuse, as well as the geometric shapes and their positioning, depending on the requirements and needs

Much lower cost compared to other energy dissipaters in the field of structural and earthquake engineering

Although seismic design codes attempt to prevent the collapse of buildings, they accept heavy damages to structures in severe earthquakes. This regulation will result in undesirable results, especially in populated cities, including: loss of residence or work place of many people for a long time, difficult and time consuming of demolition of damaged buildings, difficult, costly and time consuming debris disposal caused by the destruction of heavily damaged buildings.

This is while by repairable design of buildings using the idea of "damage direction", which means to direct the damage caused by the earthquake to certain parts of the structure as energy absorbers (fuses), so that the main components of the structure remain intact, cathese undesirable consequences can be avoided Although the method has already been proposed for pipelines, it can lead to a new generation of earthquake resistant buildings and other earthquake-resilient structures if employed in these systems. Researchers have presented similar ideas to the idea of "damage directing" for building systems, among which the use of energy absorbing components or structural fuses can be mentioned. The idea of structural fuse was introduced in the 1970s and 1980s by Fintel and Ghosh (1981) and were developed more in recent years.

It should be noted that although the main idea of concentration of damage in fuses is similar to the mentioned studies, in those studies the building does not remain at the Immediate Occupancy (IO) performance level in reality and at least parts of it require major repairs, that will be associated with the interruption in the building’s operation . In order to make the structure easily repairable after an earthquake, it is possible to combine the use of a fuse with a specific motion mode of a structure such as rocking or seesaw motion, so that severe plastic deformations occur only in the lowest floor of the building in certain fuses and the upper floors remain elastic. Azuhata from Japan introduced the idea of rocking motion in two-dimensional frames for the first time in 1998 and demonstrated the change in the behavior of structure from shear mode to rocking mode, which caused increase in the period of structure and reduction in base shear and acceleration and relative deformation in the building’s floors. Later, rocking/seesaw motion in multi-span three-dimensional frames was studied. In the design, proposed in this invention, a particular structural fuse, which has many features, mentioned above, is used.

A sample of the MTYPED device used in this invention has been made and a test has been carried out on it to show its appropriate energy absorption behavior.

The device is installed in structures and buildings and dissipates the energy entering the structure during the earthquake. This will prevent the flow of energy in the members of the structure and damage to the building. The intense motion of land during the earthquake has led to entering destructive energy into the structure (including the buildings) and, thus, leads to large motions in them. Large seismic motions in weak structures (such as a beam or column) cause damage to them and collapse in some cases. Hence, by placing these fuses in the peripheral and central foundations of the building, it controls the way of motion during the earthquake and directs the destructive energy applied from the earthquake to the building towards the fuses. Using the device, the heavy motions of the building between the floors during the sweep are significantly reduced.

The seesaw system is assigned to low-rise buildings that, using the consisting central support and the modified MTYPED devices, it is located in the center of the building foundations and peripheral foundations of the building, respectively, and, by creating seesaw structural motion and reducing the force caused by earthquake to the building, prevents serious damage to the building during the earthquake and absorbs the input energy of the earthquake. The system reduces to about 80% of the damage to the structural skeleton, both structural and non-structural components.

The system has fuses in peripheral foundations of the building and a central fuse installed and embedded in the center of the building foundation. By placing a super joint attached to a building by a truss part and by placing the fuses under the peripheral columns, the motion of the building is converted from the shear shape during the earthquake to seesaw structural behavior. In the event of an earthquake, there will be much less force to the foundation of a seesaw building and there will be fewer problems for soil under the foundation. 4 fuses have been installed in the peripheral foundations of the building, which has an outer box attached to the building foundation. Each side of these boxes has a horizontal slit. A steel plate with a varying width of its specific shape, (trapezoid) steel shape, is passed from each horizontal slit that the narrower edge of the trapezius enters the gap formed in one of the sides of the building peripheral columns in their lower part. The remarkable feature of these fuses is that they have a steel plates with specific shape and varying width, (trapezoidal), so that there is a significant potential for dough deformation in the steel plates and uniform expansion of the dough strains in their lengths and the bending moment in these plates increases linearly from the column to the outer sheath, so the basis of the bending point of the steel plates is also linearly extending from the free end to the support. The bending stresses remained almost fixed in length of the steel plates and, by entering the steel plates into the dough area of the material, the bending stress across the entire length of steel plates almost uniformly reaches the dough stress and causes the dough deformation to extend in length of the steel plates instead of focusing at clamped end of the steel plates. The force applied to the steel plates from the column base produces a moment to the end of the steel plates, otherwise, based on the fatigue phenomenon in the low number of loading cycles, steel plate experiences an early failure after 10 to 15 cycles. The high energy absorption capacity of fuses can be shown by the hysteretic force-displacement graph. The hysteretic behavior of the sample is quite stable and has wide loops with a large surface, which indicates the high energy absorption capacity of the fuses. Apart from the square shape, these boxes can be triangle, circle, rectangle and hexagon with curved edges. Four a steel plates with specific shape and varying width, (trapezoidal) are made of steel ST 37 (conventional mild steel in steel buildings). The size and thickness of the steel plates varies depending on the types and floors of building. In general, the geometric properties of the steel plates are calculated with formula 2, as well as the geometric dimensions of the steel plates and their number are determined according to the sizes of the building. After the earthquake, a steel plates with specific shape and varying width, (trapezoidal) affected can be alternately replaced by new steel plates. To replace the steel plates, we jack the building that is tilted caused by earthquake and bring it to the initial balance. Then, a handle has been embedded at the bottom of the steel plates which can be easily pulled out from the slot by a lever and replaced.

1. This device provides a seesaw structure to the structure of the buildings during the occurrence of an earthquake that is completely new in the construction with unique technology.

2. It can be constructed and assembled using conventional tools in steel workshops.

3. There is no need for advanced technology to install it.

4. If necessary, after a major earthquake, trapezoidal steel plates, as the main sources of energy destruction, can easily be replaced by new units.

5. The cost of manufacturing the device is very low compared to other energy stimulants used in seismic protection of structures.

6. Depending on the type of building and its dimensions, trapezoidal steel plates vary in size and thickness.

7. The proposed device is used at the bottom of the columns at the ground level, giving them an axial deformation of energy discharge along with the hidden motion of the entire building.

The drawing figures depict one or more implementations in accord with the present teachings, by way of example only, not by way of limitation. In the figures, like reference numerals refer to the same or similar elements .

Fig.1

is the hysteretic force-displacement graph indicates the high energy absorption capacity of the fuses. The hysteretic behavior of the sample is quite stable and has wide loops with a large surface, which represents the high energy absorption capacity of the fuses, consistent with one or more exemplary embodiments of the present disclosure.

Fig.2

Calculating the size and thickness of the steel plates, and in general, the geometric properties of the steel plates are calculated by this formula. Depending on the types and floors of the building, the geometric dimensions of the steel plates and their number are determined according to the sizes of the building, consistent with one or more exemplary embodiments of the present disclosure.

Fig.3

It shows types of fuses, which are different depending on building and shape of column , consistent with one or more exemplary embodiments of the present disclosure.

Fig.4

View of installing fuses in the central foundation and peripheral columns’ foundations of a seesaw building , consistent with one or more exemplary embodiments of the present disclosure.

Fig.5

View of installing fuses in the central foundation and peripheral foundation of a multi-storey low-rise building , consistent with one or more exemplary embodiments of the present disclosure.

Fig.6

The upper view of the fuses, which includes the outer box and the column placed inside the box, also includes a steel plate with a varying width in the trapezoidal shape, which pass through the outer box slot to the column slot, consistent with one or more exemplary embodiments of the present disclosure.

Fig.7

Steel plates with specific shape and varying width (trapezoidal) are made of steel ST 37 (common mild steel in steel buildings) , consistent with one or more exemplary embodiments of the present disclosure.

Fig.8

General view of MTYPED fuses, consistent with one or more exemplary embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

By installing these fuses in the central foundation and peripheral foundations of low-rise buildings during the earthquake, the above system finds a seesaw state, and the fuses absorb the energy from the earthquake by the trapezoidal steel plates designed with varying width and prevent damage to the building.In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings.

The following detailed description is presented to enable a person skilled in the art to make and use the methods and devices disclosed in exemplary embodiments of the present disclosure. For purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the present disclosure. However, it will be apparent to one skilled in the art that these specific details are not required to practice the disclosed exemplary embodiments. Descriptions of specific exemplary embodiments are provided only as representative examples. Various modifications to the exemplary implementations will be readily apparent to one skilled in the art, and the general principles defined herein may be applied to other implementations and applications without departing from the scope of the present disclosure. The present disclosure is not intended to be limited to the implementations shown, but is to be accorded the widest possible scope consistent with the principles and features disclosed herein.

For purposes of reference, it should be understood that the techniques and systems disclosed herein are applicable to coupled motion in a wrist; however, the techniques and systems may be adapted to a number of other applications…

FIG. 8 illustrates General view of MTYPED fuses, according to an embodiment herein. With respect to FIG. 8, An outer box attached to the foundation of building and there is a slot on each side 1 , The building column is placed by the crane in the middle of the box and the steel plate with varying width is passed from its slots 2 , It includes handle of steel plates with specific shape and varying width (trapezoidal) that can easily be pulled out by lever for the replacement of steel plates 3 , Rods attached to the roller to facilitate the replacement of steel plates 4 , Roller attached to the rod to facilitate the replacement steel plates 5 , Handle bolts 6 .

While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that the teachings may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all applications, modifications and variations that fall within the true scope of the present teachings.

Unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. They are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain.

The scope of protection is limited solely by the claims that now follow. That scope is intended and should be interpreted to be as broad as is consistent with the ordinary meaning of the language that is used in the claims when interpreted in light of this specification and the prosecution history that follows and to encompass all structural and functional equivalents. Notwithstanding, none of the claims are intended to embrace subject matter that fails to satisfy the requirement of Sections 202, 204, or 206 of the Patent Act, nor should they be interpreted in such a way. Any unintended embracement of such subject matter is hereby disclaimed.

Except as stated immediately above, nothing that has been stated or illustrated is intended or should be interpreted to cause a dedication of any component, step, feature, object, benefit, advantage, or equivalent to the public, regardless of whether it is or is not recited in the claims.

It will be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study, except where specific meanings have otherwise been set forth herein. Relational terms such as “first” and “second” and the like may be used solely to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, as used herein and in the appended claims are intended to cover a non-exclusive inclusion, encompassing a process, method, article, or apparatus that comprises a list of elements that does not include only those elements but may include other elements not expressly listed to such process, method, article, or apparatus. An element proceeded by “a” or “an” does not, without further constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is not intended to be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various implementations. Such grouping is for purposes of streamlining this disclosure, and is not to be interpreted as reflecting an intention that the claimed implementations require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed implementation. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separately claimed subject matter.

While various implementations have been described, the description is intended to be exemplary, rather than limiting and it will be apparent to those of ordinary skill in the art that many more implementations are possible that are within the scope of the implementations. Although many possible combinations of features are shown in the accompanying figures and discussed in this detailed description, many other combinations of the disclosed features are possible. Any feature of any implementation may be used in combination with or substituted for any other feature or element in any other implementation unless specifically restricted. Therefore, it will be understood that any of the features shown and/or discussed in the present disclosure may be implemented together in any suitable combination. Accordingly, the implementations are not to be restricted except in light of the attached claims and their equivalents. Also, various modifications and changes may be made within the scope of the attached claims.

Due to the variable shape of the fuses, as well as the variable thickness and steel plate size, the system can be used in low-rise buildings. It can also be used in office buildings, hospitals, schools, and all houses.

Claims

Seesaw Structural System (SSS) for aseismic -Llow-rise buildings by using a Specific Central "Semi-Sphere and Bowl" mega support and Modified MTYPED Devices which are, respectively, located at the center of building's foundations and the foundations of the peripheral columns of the building, and by creating seesaw structural motion and reducing the force imposed by earthquake to the building, prevents serious damage to the building during the earthquake and absorbs the input energy of the earthquake.
According to claim 1, this system has fuses in the peripheral foundations of the building, and a central fuse installed and embedded in the center of the building's foundation.
According to claim 2, by placing the mega support, on which places a relatively stiff truss for supporting the building superstructure, and by placing the fuses under the peripheral columns, the motion of the building is changed from the shear type during the earthquake to seesaw structural behavior.
According to claim 3, much less force is applied in the foundation of a seesaw building during an earthquake, and less problems are encountered for the soil under foundation.
According to claim 2, each fuse has an outer box attached to the foundation of building. Each side of these boxes has at least one horizontal opening (slit) .
According to claim 5 and Graph ??, the shape of the outer box can be triangular, circular, rectangular or hexagonal, in addition to the square.
According to claim 5, a steel plate with specific shape and varying width (trapezoidal), is passed from each slit that the narrower edge of the plate enters the gap formed in one of the sides of the building peripheral columns in their lower part.
According to claim 7, the shape of the steel plates can have curved edges instead of straight edges.
According to claim 7, each column of the building is guided by the crane for installation to the center of the outer box and the tip of each trapezoidal plate is inserted into the column slit and the column is fixed in the center of the outer box, which it itself fixed on its base.
According to claim 9, the outstanding feature of these fuses is that they have steel plates with specific shape and varying width, (trapezoidal or tapered), so that there is a significant potential for plastic deformation in steel plates and uniform expansion of the plastic strains in their lengths.
According to claim 10, the reason for selecting the plates in the form of a trapezoid, or tapered, is that the bending moment in these plates increases linearly from the column outward to the outer box, so the bending strength of the steel plate is also linearly varying from its free end toward its fixed end.
According to claim 11, bending stresses remains almost constant along the length of the steel plate and, by entering the steel plate into the plastic range of the material, the bending stress across the entire length of steel plate almost uniformly reaches the yielding stress and causes the plastic deformation to extend in length of the steel plate instead of concentrating at its clamped end.
According to claim 12, the steel plates are tapered to prevent the low-cycle fatigue phenomenon due to concentration of plastic deformations at the clamped end of plates., otherwise steel plate experiences an premature failure after only 10 to 15 cycles.
According to claim 13, the high energy absorption capacity of a fuse can be observed through the hysteretic force-displacement graph. The hysteretic behavior of the tested sample is quite stable and has wide loops with a large area, which indicates the high energy absorption capacity of the fuses (Graph 1).
According to claim 14, four a steel plate with specific shape and varying width, (tapered) are made of steel ST 37 (conventional mild steel in steel buildings).
According to claim 15, the size and thickness of the steel plates can be determined depending on the dimensions and number of floors of the building. In general, the geometric properties of the steel plates are calculated with formula 2, and the geometric dimensions of the steel plates and their number are determined according to the building’s geometry.
According to claim 16, after the earthquake, each steel plate can be replaced by new steel plates.
According to claim 17, one of the advantages of the proposed fuse system is replaceability of steel plates. A handle has been installed at the back of supporting end-plate of the tapered steel plates by which the plate can be easily pulled out from the slit and be replaced by a new one.
According to claim 18, to replace the steel plates, the building that has been tilted due to earthquake is brought back to its initial balance position by using some jacks, to make easier thereplacement of the steel plates.
According to claim 1, in general, this system reduces about 80% of damage to the structural system, concerning both structural and non-structural components.