MXPA00003897A - Method and apparatus to control seismic forces, accelerations, and displacements of structures - Google Patents

Abstract

A seismic energy dissipation system for use with structures such as buildings, bridges and the like. The system includes a gravity frame (40), at least one reaction frame (41), and connection apparatus for connecting the gravity frame and the reaction frame. The connection apparatus includes springs (30) for setting a period of response and energy dissipation units (31) for dissipating energy within the structure (20), thus controlling the response of a structure with respect to internal forces, accelerations and deformations due to external excitations such as wind or earthquake.

Description

METHOD AND APPARATUS FOR CONTROLLING SEISMIC FORCES, ACCELERATIONS AND DISPLACEMENTS OF STRUCTURES BACKGROUND OF THE INVENTION 1. Technical Field This invention relates to a system for damping and limiting internal forces, accelerations, displacements, etc. caused by external excitations such as earthquakes and wind in structures such as buildings and bridges, and more particularly, to a structural system in which the response periods, deflection patterns and damping capabilities of the structure are adjusted by the invention in order to dissipate seismic energy and control internal forces, displacements and accelerations.

Description of the Previous Technique In order to protect a structure such as a building or bridge, as well as people who can occupy or be in the vicinity of such REF .: 119754 structures, have been considered systems that resist seismic forces. These systems occasionally include active and / or passive seismic energy dissipation devices. These systems try to protect the structure of the total collapse and control the damage in response to the seismic forces created by earthquakes or tremors. Typically a local building code establishes minimum equivalent seismic forces that must be resisted by the structure, based on various parameters. The magnitude and distribution of these forces are generally determined as a function of the mass of the structure, its vibrational properties (response periods), regional seismicity, local soil conditions, the type of seismic system, and the importance of the structure. For conventional structures that include a system that resists earthquakes, such as a seismic reinforcement system, predominant response periods and damping capabilities are effectively "integrated into" the system as determined by its mass and the configuration and properties of the system. material of the elements that comprise the seismic reinforcement system.

These elements usually consist of various types of structural networks and / or frameworks. The response period of the structure and its damping capabilities affect the internal forces, accelerations, and displacements of the structure in response to a given earthquake or tremor. With conventional reinforcement systems, the elastic, lateral seismic response of a structure is affected by the rigidity of the seismic system in relation to the shaking characteristics of the earthquake and the damping properties of the system. In general, moderate to large earthquakes, at moderate to large distances from one site of the structure, produce larger forces in stiffer structures and smaller forces in softer structures when the floors under the structure are at least moderately rigid. Under the conditions described above, the relative deflections are smaller for stiffer structures and larger for softer structures. These general relationships may not be valid if the - .. structure is located very close to a seismic fault that is separated or if the structure is placed on extremely soft soils. In general, a stiffer structure must be made stronger than a softer structure to elastically resist larger seismic forces. The stiffer structure produces higher internal accelerations that can adversely affect its contents. When a rigid structure is not made strong enough to resist elastic seismic forces, they sustain structural damage. By sustaining the damage, the structure dissipates the seismic energy. The internal forces are limited to the elastic resistance of the structure. The structure effectively softens and undergoes larger displacements. These larger displacements are internal elastic deformations that can increase structural damage. On the other hand, a softer structure can in general be made relatively weaker than the stiffer structure and still resist elastically the seismic forces coming from a given earthquake. As with a rigid structure, when the soft structure is not made strong enough to resist elastic seismic forces, it also dissipates seismic energy by sustaining structural damage. The soft structure can undergo large deformations that can adversely affect non-structural elements by subjecting them to structural deformations. The ability of a structure to sustain significant structural damage without significant loss of strength, (eg, structures with high ductility) is explained in the local building code. Structures with high ductility can be designed to be weaker than those with lower ductility. The supplementary damping can be provided by the addition of Energy Dissipating Units (EDU) within the reinforcement elements of a conventional system for seismic reinforcement. The added damping improves the seismic performance of the structure by reducing deflections, accelerations and structural and non-structural damage. Figure 20 graphically illustrates the general relationships between acceleration, response period and damping, for a simplified model that can be used to understand complex structures. There are several basic relationships of resistance, rigidity and ductility of the structural systems that affect the current design practice. Some of these relationships include: For a given size and type of structure, an increase in strength usually results in an increase in stiffness; An increase in stiffness usually results in an increase in seismic forces, internal accelerations (and potential damage to the content), and a decrease in deformation; A decrease in strength usually results in an increase in the demand for ductility or the demand for damping; An increase in supplemental damping usually results in a decrease in forces, deformations, internal accelerations, and structural and non-structural damage; and Relative improvements in resistance, ductility and damping of a system usually result in added costs. A typical arrangement of supplemental damping within a frame structure for the moment is illustrated in Figure 1. All or part of the lateral static stiffness of the system is a result of the flexural stiffness of the beams 13 and the columns 14 that are connected with a rigid or semi-rigid joint also known as a moment joint 15. The reinforcements or clamps 10 are added to the structure or framework between each level, in order to couple the levels with an Energy Dissipation Unit (EDU) 11. The energy dissipation devices can work by using various mechanisms such as friction, elastic metals, energy absorbing plastics, rubbers, etc., and forced fluids through holes. These devices (EDUs) can be activated by the relative displacement between each level, by the relative speed between each level, or by the active control methods. The EDUs can also provide additional static rigidity to the structure by means of clamps or reinforcements. In a second common arrangement illustrated in Figure 2, a reinforcement 10 extends diagonally between the portions of a structure with an EDU 11 in the intermediate part. Supplementary damping devices can add substantial costs to conventional seismic reinforcement systems. To date, the costs associated with the installation of these devices has been a factor in their limited use. Another prior art system illustrated in Figure 3 also has an insulation layer under the entire building and is commonly referred to as a base insulation system. The insulation layer uses insulators 16, generally in the form of bearings, and controls the accelerations imparted and deformations, in two ways: by affecting the response period of the structure, since the bearings are relatively soft when fastened to lateral land accelerations; and by providing damping. The optional supplementary damping devices 11 can be added. The damping devices (those integral with the bearings and supplementary) help control the deformations, accelerations and forces of the structure. The structural system above the insulators tends to be similar to that of a conventional seismic reinforcement system; however, the isolated structure would tend to sustain less damage during a large earthquake. Since the insulation layer is soft, the structure experiences large movements or horizontal "displacements" (even with optional damping devices). These displacements, which are generally between thirty and sixty centimeters (one and two feet), must be accommodated by the various building systems, such as elevators, pipelines, power lines, etc. In addition, the building must be separated from and left to deform in relation to the surrounding degree by means of a special covered joint or seismic joint. Base insulation buildings tend to perform better than those with conventional seismic reinforcement systems during earthquakes. However, there are significant aggregate costs associated with the installation of a base insulation system that are attributed to the insulators, to the joint, and to the special details of the construction system, necessary to accommodate the large deformations.

These costs, to date, have limited the use of the base asylee systems. Consequently, a seismic system is needed to control loads, internal accelerations, deformations, and structural and non-structural damage that is economical and non-invasive to the function of the building.

BRIEF DESCRIPTION OF THE INVENTION A cushioned, synchronized or adjusted structural system, according to the present invention, as well as a method of use for the same, faces the drawbacks of the prior art. According to one aspect of the present invention, a system for use with a structure such as a building or a bridge to dampen internal forces, limit accelerations and displacements caused by external excitations, such as, for example, earthquakes , explosions, wind, etc., includes a structure or gravity framework, at least one reaction framework and the connecting apparatus for connecting the gravity framework and the reaction framework. The connecting apparatus includes at least one spring to establish a response period and at least one damping device to dissipate seismic or wind energy within the structure, caused by external excitations. According to yet another aspect of the present invention, the system includes at least four reaction frames. Each reaction framework is contained within a different vertical plane of the structure. According to yet another aspect of the present invention, the structure is a building that extends over one or more floors or floors vertically. The system includes multiple springs and multiple damping devices in the form of energy dissipation units. Each plant includes at least one spring and at least one energy dissipation unit for connecting the reaction framework to the gravity framework. According to yet another aspect of the present invention, the gravity frame comprises multiple beams and columns, and the columns of the first level of the gravity frame include rotationally low rigidity connections at the top and bottom, to minimize rigidity of the frame, and to minimize the internal forces in the columns of the first level. According to a further aspect of the present invention, the reaction framework is connected to the floor via rotationally flexible connections, in order to minimize internal forces due to the departure from the flexure of the plane. According to yet another aspect of the present invention, the columns of the first level of the gravity frame are connected to the rollers of the base insulation which are connected to the ground. According to a further aspect of the present invention, the base insulation rolls are low friction pads. According to yet another aspect of the present invention, the system further includes wind fuses between the gravity frame and the reaction frame, to rigidly connect the frames during low level winds and earthquakes, the wind fuses are decoupled during large external excitations. According to an alternative embodiment of the present invention, the reaction framework is rigidly linked to the gravity framework.

According to one aspect of the alternative embodiment, the system is configured such that it includes at least one fitted-cushioned frame that includes a pair of clamps or diagonally extending reinforcements, located between two columns and two beams and defining a vertex. , at least one spring connecting the pair of rigidly linked gravity and reaction frames, and at least one damping device connecting the pair to the rigidly linked gravity and reaction frames. According to yet another aspect of the alternative embodiment, the system comprises at least four aj-damped frames. Each used-damped frame is contained within a different vertical plane defined by the structure. According to another aspect of the alternative modality, the structure is a multi-storey building and each floor has at least four cushioned-cushioned frames. Each used-damped frame of each floor is contained within a different vertical plane defined by the building.

According to another aspect of the alternative modality, the system is comprised of two columns with rotationally low rigidity connections in their bases, and beams that are structured within these columns with rotationally low rigidity connections to minimize rigidity to the frame. gravity and rigidly joined reaction and minimize internal forces in the system. According to yet another aspect of the present invention, a method for damping internal forces, limiting accelerations and shifts within a structure such as a building or a bridge, caused by external excitations, including the structure a gravity frame and a reaction framework, includes connecting springs between the reaction framework of the structure and the gravity framework of the structure, and the connection of the energy dissipation units between the reaction framework of the structure and the gravity framework of the structure. According to yet another aspect of the present invention, the method further includes the selection of a desired period of response of the structure to the external excitations, configuring the springs based on the desired response period, selecting a desired level of damping in order to limit the accelerations and displacements within the structure, caused by the external excitations, and configuring the energy dissipation units based on the desired level. Accordingly, an aj-damped structural system according to the present invention, for use in buildings, bridges and the like, includes energy dissipation devices, springs, a gravity framework, and accommodating reaction frames to independently establish the response period of the structure, the deformation patterns of the structure, the strength of the structure and the damping capacity of the structure. With the preferred embodiment of the present invention, the coupling of the frame carrying the gravity load and the seismic load reaction frames, in the case of buildings, occurs at the level of the floor diaphragm. As with the practice of traditional seismic engineering, the distributed mass of the building can be approximated as concentrated masses in each floor diaphragm. The design of the frame carrying the gravity load can be detailed such that its lateral stiffness can be analytically neglected. The seismic load reaction framework can be designed with a very high stiffness and a very small mass, resulting in very small response times. As such, the response of the reaction framework will approach that of the movement of the ground. Since the seismic reaction frames are essentially rigid, and the frame carrying the gravity load is essentially flexible, the full lateral stiffness of the building is determined by the plurality of springs. In addition, the complete damping capabilities of the construction are determined by the plurality of energy dissipating devices. In addition, the building can be mathematically modeled as a series of independent structures of simple degree of freedom, in which parameters such as mass, stiffness, and damping are assigned for each plant. As such, the response of a building to a given earthquake can be analytically determined and characterized by periods of response, accelerations, forces and deformations. Other features and advantages of the present invention will be understood after reading and understanding the detailed description of the preferred exemplary embodiments, found hereinafter, in conjunction with reference to the drawings, in which similar numbers represent similar elements.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a seismic energy dissipation system of the prior art; Figure 2 is a schematic illustration of a second seismic energy dissipation system, of the prior art; Figure 3 is a schematic illustration of a third seismic energy dissipation system, of the prior art; Figure 4 is a schematic illustration of a structural damped, adjusted system according to the present invention; Figure 5 is a schematic illustration of the snug, tight structural system illustrated in Figure 4, where the gravity frame is connected to the floor via low friction pads; Figure 6 is a schematic plan view of a floor structuring plane for a steel frame building illustrating an arrangement of gravity frames and reaction frames of a cushioned and adjusted structural system, in accordance with the present invention; Figure 7 is an elevation view of a first level column of the gravity frame having spigot connections; Figure 8a is an enlarged view of a connection within a first level column of the gravity framework, of a structural damped and adjusted system, according to the present invention; Figure 8b is a plan view of the connection illustrated in Figure 8a; Figure 9 is an enlarged view of a first level column of the gravity framework illustrated in Figure 5; Figure 10 is an elevation view illustrating a possible arrangement of a reaction framework of the steel construction; FIG. 1a is an enlarged, front elevational view of a possible connection of a column of the reaction frame, illustrating a hinged connection that could minimize the internal stresses due to the deflection output of the plane; Figure 11b is an enlarged, side elevational view of the connection illustrated in Figure Ia; Figure 11c is an enlarged, front elevational view of an alternative connection of a column of the reaction frame, illustrating a hinged connection that could minimize the internal stresses due to the bending output of the plane; Figure 1 is an enlarged side elevational view of the connection illustrated in Figure 5; Figure 12a is an enlarged elevation view of a meeting point of the diagonal reinforcements and the base of a reaction frame; Figure 12b is an enlarged sectional view of the meeting point illustrated in Figure 12a; Figure 13 is an enlarged, elevational view of a meeting point between a gravity frame and a reaction frame, of a cushioned and adjusted structural system, according to the present invention; Figure 14 is a plan view of a possible arrangement of springs and dampers interconnecting the gravity frame and the reaction frame of a cushioned, adjusted structural system according to the present invention, as indicated by the line Figure 14 -Figure 14 in Figure 10; Figure 15a is a sectional view of the damping connection to the reaction frame, as indicated by the line Figure 15a-Figure 15a in Figure 14; Figure 15b is a sectional view of the damping connection to the gravity frame, as indicated by the line Figure 15b-Figure 15b in Figure 14; Figure 16a is a sectional view of the damping connection to the gravity frame, as indicated by the line Figure 16a-Figure 16a in Figure 14; Figure 16b is a sectional view of the damping connection to the reaction frame, as indicated by the line Figure 16b-Figure 16b in Figure 14; Figure 17 is an elevation view of an alternative configuration according to the present invention, using a viscoelastic spring / buffer combination; Figure 18a is a plan view illustrating another arrangement of springs and dampers as indicated by the line Figure 18a-Figure 18a in Figure 10; Figures 18b and 18c are partial elevation views illustrating the arrangement of springs and dampers illustrated in Figure 18a; Figure 19 is a schematic illustration of an alternative embodiment according to the present invention; and Figure 20 is a graph illustrating the relationship between the response period, damping and acceleration.

DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY MODALITIES The present invention can be used with structures, such as, for example, buildings, bridges, elevated roads, and elevated railway tracks. For simplicity and clarity, it will be described with reference to the use of it with a building. Returning to Figure 4, a system for dampening or limiting internal forces caused by external forces, such as earthquakes, is schematically illustrated in accordance with the present invention. With this arrangement, a snug, cushioned structure 20 comprises a gravity frame 40 and at least one reaction frame 41. In this embodiment, the gravity frame 40 comprises the columns 21a and the beams 22a, while the reaction frame 41 it comprises the columns 21b and the beams 22b. As can be seen in the Figure 10, the reaction frame also includes the clamps or reinforcements 23 accommodated in a substantially inverted V shape, which could be in a V-shaped, X-shaped, etc., with a pair of reinforcements present on each floor . The reinforcements, the columns and the beams are joined in various places with the joints 24. In addition, in this embodiment, the gravity and reaction frames are connected to the floor by means of joints 50 and 70 at a base of the structure that uses the system . The reaction framework 41 may consist of various materials and configurations such as, for example, reinforced concrete walls, reinforced masonry, wood, steel, etc .; abutments of rock or soil; reinforced steel frames, or reinforced concrete, steel moment frames, reinforced concrete, etc; or similar. The reaction frame 41 needs to be clearly connected rigidly to the floor. In the preferred embodiment, the gravity frame and the reaction frame are connected via a plurality of springs 30 and dampers or the power dissipation unit (EDU) 31. The springs are configured in order to adjust the response period for the building through the stiffness of the spring. The response period is established by adjusting the stiffness of springs 30. A stiffer spring creates a stiffer structure with a lower response period, while a "softer" spring creates a softer structure with a longer period Highest response In conjunction with the stiffness of the springs, which have established the response period, the energy dissipation units will be adjusted to size and configured in order to establish a level of damping to dissipate the energy caused by external excitations. In a preferred embodiment, a minimum of a spring and a shock absorber or EDU connect each reaction frame to the gravity frame. However, springs and dampers are generally additive and therefore multiple small springs can be used to create the full spring effect of a large spring. Similarly, multiple small shock absorbers can be used to create the full effect of a large shock absorber. Finally, it is also true that springs have their own inherent damping effect and EDUs have their own inherent spring effect. These cushioning and spring effects are additive for full cushioning and rigidity.

The mass (weight) associated with the complete structure 20 carried on each floor is represented by blocks 24 in Figures 4 and 5. In order to explain the total load within the building, sufficient reaction frames are used when creating the complete structure 20. Figure 6 illustrates a possible floor structuring plane for a steel frame building using the system according to the present invention. Four reaction frames 41 are interleaved within the gravity frame 40 to create the snug, cushioned structure. In order to comply with most local building codes, four reaction frames 41 are typically required, with each reaction frame 41 being in a different vertical plane. The reaction frames are not required to be through each other. More or less reaction frames 41 can be used depending on the shape or size of the building. With the damped, adjusted structure 20, the forces within the buffers and springs are not additive from floor to floor and the forces are approximately the same on each floor when the plants have masses, springs and similar power dissipation units. The mass is coupled to the stiffness of the spring but decoupled from the stiffness of the reaction frame 41, and the masses in each plant can be effectively decoupled from one another. The effect of gravity on the mass is effectively carried by the gravity frame 40. The reaction frame 41 is effectively rigidly connected to the base of the building 57. Consequently, the individual floors of the building do not interfere with each other and the system of passive seismic energy dissipation within the adjusted, cushioned structure isolates floor by floor and therefore each floor acts basically as a single-floor structure. This is much less disruptive to the function of the building as opposed to other seismic energy dissipation systems that isolate the entire structure together from the seismic forces. In addition, compared to the seismic energy dissipation systems of the prior art, such as the base isolation system, the passive, seismic energy dissipation system according to the present invention is estimated to cost significantly less.

Figures 7, 8a and 8b illustrate how the columns 21a within the gravity frame are preferably connected to a first level. The first level may be at ground level or below ground, depending on the building, for example, whether the building extends below the ground or not. A lower column 49a is joined to an upper column 49b by joints of low rotational rigidity, commonly referred to as spigot joints 50. A spigot joint 50 is also used to connect the lower column 49a to the base 57 of the building or floor. These spigot joints allow the gravity frame 40 to be "soft" to contribute this only to the marginal stiffness for the system. As can be seen in Figures 8a and 8b, the spigot joints 50 comprise a circular bearing 51 which is placed between two adjacent columns 49a and 49b. Four bolts 52 are used to connect the adjacent column sections with the Belleville spring washers 53. Figures 5 and 9 illustrate an embodiment in which the gravity frame 40 is supported by rollers 60 at a first level. The rollers 60 make the gravity frame 50 even softer and replace the first level of the spigot joints 50 to thereby connect the column sections 49a to the base 57. As can be seen in Figure 9, the rollers 60 are preferably in the form of low friction pads. An example of such a pad comprises the PTFE fabric, available from Merriman, Inc., located at 100 Industrial Park Road, Hingham, Massachusets 02043, and having a coefficient of friction of about 0.04. The rollers 60 are placed on plates 61 that are on the bases 62. The bases 62 are bolted to the base 57 of the building with bolts 63. FIGS. 11 and 11b illustrate a possible way in which a column 21b in the reaction frame 41 You can be connected to the base 57 of the building or the ground. A flexible joint 70 which is rotationally flexible is used, which includes a base 71 and a body 72. The base 71 and the body 72 each include multiple fingers 73 projecting therefrom and intertwining. A bolt 74 connects the base 71 and the body 72. The base 7.1 is embedded within the base 57 of the building, surely with head studs 75. Because the reaction shell 41 is extremely rigid, the flexible joint 70 allows the columns move in response to the out-of-plane forces without experiencing large internal stresses. Figures 11c and lid illustrate an alternative example of how a column 21b in the reaction frame 41 can be connected to the base 57 of the building or to the ground. A flexible joint 70 is used, which includes a base 71 and a body 72. The base and the body are connected by bolts 74. The Belleville spring washers 53 are used as flexible spacers. Figures 12a and 12b illustrate a manner in which reinforcements 23 within an - > Reaction frames can be connected to the base of the building with a flexible joint that allows the reinforcements to move out of the plane without experiencing large external stresses. A beam 76 is sunk into the ground or the base of the building. The double angles 77 are bolted to the beam 76 and the plate 78. The Belleville spring washers 53 are provided between the double angles 77 and the plate 78. A clearance is provided between the bracket 78 and the floor 79 of the first level to allow flexion. Figure 13 illustrates how a reaction frame 41 and a section 40 of the adjacent gravity frame can be physically interconnected. The section 40a of the gravity frame "shares" the column 21b with the reaction frame 41. The floor beam 80 is connected to the column 21b by means of a sliding connection 81. A clearance G is provided between the beam 80 of floor and floor slab 82 and column 21b. In the same way, a free space G is provided between floor slab 83 and column 21b. Preferably, the free space G is approximately 5 cm (2 inches), but may be larger or smaller, depending on the design requirements. A beam 84 is also connected to the column 21b with a sliding connection. Figures 14-16 illustrate an example of an arrangement for connecting the springs 30 and the EDUs 31 to the gravity frame and the reaction frame. Obviously there are numerous such arrangements. In the exemplary arrangement illustrated in Figures 14-16, the springs 30 are connected to the beams 91a and 91b of the gravity frame via the bracket 92 and the rod 95, and are connected to the beam 90 of the reaction frame by means of the bracket 96 and the rods 95. Two EDUs 31 are connected to the beams 91a and 91b of the gravity frame via the bracket 93 and are connected to the beam 90 of the reaction frame by means of the bracket 9. The springs 30 used to establish a response period can be of a variety of materials and configurations, and can be accommodated to show a variety of variable stiffness characteristics, to control the loads developed by a structure and the deformations of the structure. The springs 30 are preferably large heavy-duty springs and can be of a variety of shapes. Excellent results have been obtained with arrangements of conical steel plates known as Belleville Springs or Disc Springs, which can be obtained from Solo Manufacturing Company, 425 Center Street, Chardon, Ohio 44024-2027, and other manufacturers. Another spring that has provided satisfactory results is MARSH MELLO manufactured by Firestone, 1700 Firestone Blvd., Noblesville, IN 46060. As previously stated, multiple springs can be used to provide the required "spring effect". The added effect of the springs can be created by combining various linear and non-linear springs in series and / or in parallel and with clearances to delay the coupling of a particular spring. The aggregate effect of the plurality of springs can be described as a simple spring with linear or non-linear elastic characteristics. Energy dissipating units or buffers 31 connected to the frames, or to a wall or other reaction structure in a certain arrangement, establish the damping characteristics of the entire structure. A plurality of energy dissipating devices, such as, but not limited to, fluid shock absorbers, energy absorbing plastics, rubbers, etc., friction devices, and elastic steel devices, may also be used. These devices can respond passively due to displacements or relative frame speeds or they can be actively controlled.

Accordingly, during an earthquake, for example, the rigid reaction frame 41 will move with the ground while the gravity frame 40 will swing, and / or move on the optional rollers 60. The springs 30 will control the response period and the EDUs 31 will dissipate the energy during the response, dampening and limiting the movement of the gravity frame. The free spaces G allow the movement of the floors in relation to the reaction framework. In general, the design of the reaction frameworks and the gravity framework will be based on local construction codes and construction specifications, which will require springs and EDUs to be configured such that G free spaces will allow movement from 5 to 7.5 centimeters (two to three inches) during an extremely strong earthquake. However, if an unusually strong earthquake would cause the movement to exceed the free spaces G, the reaction frame 41 will serve as a "backup" by preventing further movement. The direct coupling of the two frames allows the full utilization of the force and energy dissipation capacity of the seismic reaction framework beyond the resistance of the plurality of springs and beyond the energy dissipation capacity of the plurality of springs. energy dissipation devices. Accordingly, the present invention reduces the roll and movement of the building during earthquakes when compared to the prior art systems, thereby reducing damage. Figure 17 illustrates an alternative modality where a viscoelastic EDU 100 is used. The viscoelastic EDU 100 is placed on a beam 22b of the reaction frame. A smaller beam 101 is placed on the viscoelastic EDU and under the floor 102. A lens 103 of viscoelastic material is joined between the steel plates 104a and 104b, and the assembly is placed between the reaction and gravity frameworks. The viscoelastic lens of material creates the spring effect and the damping effect when it is distorted in the cut by the relative movement of the frames. The spring effect and the damping effect is controlled by the thickness, the surface area of the lens, and the type of material specified. The material is currently used to make EDUs and is manufactured by 3M in the Division of Industrial and Specialty Tapes, 3M Center, Building 220-8E-04, St. Paul, Minnesota, 55144-1000. Supplementary springs and supplementary power dissipation units can be added to further fine-tune the system setting. The advantage of this configuration of this energy and spring dissipation device, is the simplicity of its mechanism. Figures 18a, 18b and 18c illustrate an alternative arrangement of the springs 30 and shock absorbers 31. A bracket 97 connects the springs 30 to the beam 91 of the gravity frame and also connects the EDUs 31 to the beam 91 of the gravity frame. A bracket 98 connects the EDUs 31 to the beam 90 of the reaction frame. The springs 30 are also connected to the column 21b of the reaction frame. As previously mentioned, a soft building tends to be susceptible to movement or "rocking" during high winds. In order to explain such a situation, the wind fuses 45 can be provided within the adjusted, damped structure, as illustrated in Figure 4. These wind fuses make the building more rigid, so that the rolling is reduced during strong winds, but have spikes in these that are cut during extremely high forces, such as those created by large earthquakes, to make the building less rigid or more "soft" and thereby allow relative movement between the reaction framework and the gravity frame to activate the energy dissipation units. Figure 19 illustrates schematically an alternative embodiment in which the gravity frame and the reaction frame are rigidly connected as schematically represented by 26. Typically, the rigid connection 26 is a bolted joint. Such an arrangement is termed as a tight, cushioned frame. A snug, cushioned frame 110 of a multi-story building is constituted of individual columns 21 and beam 22. The first level columns are generally connected to the base of the building rigidly, or with a flexible joint, as previously described. The reinforcements 23 are provided in a general form of inverted V (.but they could be arranged in a V-shape or -. _ in a form of X). The columns, beams and reinforcements are joined together at various sites with low rotational rigidity or with spigot joints 24. In general, beams 22 correspond to a floor or floor of the multi-storey building. Block 25 on the various beams represents the mass supported on each floor of the multi-storey building. A construction frame utilizing the snug, cushioned frame arrangement illustrated in Figure 19 would typically have four or more snug-cushion frames for each floor, arranged as shown in Figure 6. Two out of each group of four would be vertical planes generally opposite, but not necessarily directly opposite each other. Of course, additional or fewer frames could be used depending on the shape and size of the building and the local requirements of the building codes. With the frame adjusted, cushioned, in order to adequately cushion the structure, the buffer forces are generally larger in the bottom floor and progressively decrease to higher floors. The spring forces are generally additive between the floors and, as with the frames, the maximum force of the springs is located on the lower floor. It can be understood therefore that by the use of the present invention, the control of seismic loads, structural deformations and structural and non-structural damage can be achieved in originally constructed structures and in certain existing structures. A method according to the present invention comprises adjusting the desired response period of the frame carrying the gravity load through the selection of the plurality of springs. The response period can be chosen with consideration of the local characteristics of soil agitation in response to various earthquakes or earthquakes. The desired damping characteristics of the load carrying frame can be adjusted by the selection of the plurality of energy dissipating devices, and the seismic load reaction frame can be designed based on an analysis of the structure as it is subject to a earthquake given. The coupling and uncoupling of the frame systems via the coupling of the plurality of springs and the plurality of energy dissipating devices can be controlled by the use of fusible connections or links, controlled by force, and the limiting free spaces of displacement. A design process can be undertaken using the present invention, to produce structures that are highly effective in resisting the effects of earthquakes and wind. Although the invention has been described with reference to the specific exemplary embodiments, it will be appreciated that it is intended to cover all equivalent modifications within the scope of the appended claims.

It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention is that it is clear from the present description of the invention.

Claims (22)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A system for use with a structure such as a building or a bridge to dampen internal forces, and limit accelerations and displacements caused by external excitations, the system is characterized in that it comprises: a. a gravity frame; b. a reaction framework; and c. connecting means for connecting the gravity frame and the reaction frame, connecting means including spring means for adjusting a response period and the damping means to dissipate the energy, and limiting the forces, accelerations and displacements within of the structure.

2. The system according to claim 1, characterized in that the system comprises at least four reaction frames, each reaction frame is connected to the gravity frame via the connection means, each reaction frame is contained within a different vertical plane of the structure.

3. The system according to claim 2, characterized in that the structure is a building that extends over one or more floors vertically, the spring means comprises multiple springs and the damping means comprises multiple energy dissipation units, and wherein each The plant includes at least one spring and at least one energy dissipation unit for connecting the reaction framework to the gravity framework.

4. The system according to claim 1, characterized in that the gravity framework comprises multiple beams and columns, a first level of the columns includes a spigot connection in an upper part and a bottom.

5. The system according to claim 1, characterized in that the reaction framework comprises multiple beams and columns and a first level of columns are connected to the ground via rotationally flexible connections.

6. The system according to claim 1, characterized in that the gravity frame comprises multiple beams and columns, a first level of columns that is connected to the insulation rollers of the base.

7. The system according to claim 6, characterized in that the insulation rollers of the base are low friction pads.

8. The system according to claim 1, characterized in that it also comprises wind fuses between the gravity framework and the reaction framework.

9. The system according to claim 1, characterized in that the reaction framework comprises a wall comprised of at least one of a group consisting of reinforced concrete, reinforced masonry, steel and wood.

10. The system according to claim 1, characterized in that the reaction framework comprises a buttress of at least one of a group consisting of rock and soil.

11. The system according to claim 1, characterized in that at least one reaction frame is rigidly connected to sections of the gravity frame to form at least one frame used as a shock absorber.

12. The system according to claim 11, characterized in that at least one used-damped frame includes: a. a pair of reinforcements that extend diagonally, located between two columns and two beams that define a vertex; b. at least one spring connecting the torque to the rigidly connected gravity and reaction frames; and c. at least one damping device connecting two adjacent floors of the gravity and reaction frames rigidly connected via the reinforcements.

13. The system according to claim 12, characterized in that the system comprises at least four adjusted-cushioned frames, each adjusted-cushioned frame is contained within a different vertical plane, defined by the structure.

14. The system according to claim 12, characterized in that the structure is a multi-storey building and each floor has at least four aj-buffered frames, each adjusted-cushioned frame of each floor is contained within a different vertical plane defined by building .

15. The system according to claim 12, characterized in that the reaction framework comprises multiple beams and columns, and a first level of columns are connected to the ground via rotationally flexible connections.

16. A system for the use of a multi-plant structure, such as a building or a bridge, to cushion internal forces caused by external forces, the system is characterized in that it comprises: a. a gravity framework comprising multiple beams and columns; b. at least four reaction frames comprising multiple beams and columns; c. a plurality of springs, each plant of each section of the reaction frame is connected to the gravity frame with at least one spring; and d. a plurality of energy dissipation units, each plant of each reaction frame is connected to the gravity frame with at least one energy dissipation unit.

17. The system according to claim 16, characterized in that a first level of the columns of the gravity frame includes a connection of dowels in an upper part and a bottom.

18. The system according to claim 16, characterized in that a first level of the columns of the reaction frame are connected to the ground by means of rotationally flexible connections.

19. The system according to claim 16, characterized in that a first level of the columns of the gravity frame are connected to the base isolation rolls.

20. The system according to claim 16, characterized in that it also comprises wind fuses between the gravity framework and the reaction framework.

21. A method for dampening the internal force within a structure such as a building or a bridge, caused by external force, the structure includes a gravity framework and at least one reaction framework, the method is characterized in that it comprises: the connection of springs between the reaction framework of the structure and the gravity framework of the structure; and the connection of energy dissipation units between the reaction framework of the structure and the gravity framework of the structure.

22. The method according to claim 21, further characterized in that it comprises: the selection of a desired period of response of the structure to the external force; the configuration of the springs based on the desired response period; the selection of a desired level of damping within the structure, caused by external force; and the configuration of the energy dissipation units based on the desired level of damping, ACCELERATIONS AND STRUCTURE DISPLACEMENTS SUMMARY OF THE INVENTION A seismic energy dissipation system is described for use with structures such as buildings, bridges and the like. The system includes a gravity frame (40), at least one reaction frame (41), and the connecting apparatus for connecting the gravity frame and the reaction frame. The connection apparatus includes the springs (30) to adjust a response period and the energy dissipation units (31) to dissipate the energy within the structure (20), thereby controlling the response of a structure with respect to internal forces, accelerations and deformations due to external excitations such as wind or earthquakes.