COUPLING MEMBER FOR BUILDINGS WITH TWO-PHASE VIBRATION DAMPING AND LOCKING.

Abstract

A building structure comprising a plurality of elements extending from a ground surface with at least a first element connected to a second element by a coupling member, the coupling member including a damping element for damping vibrations in the building structure and a means for limiting the deformation of the damping element when the relative movement exceeds a maximum displacement at which damage occurs to the damping element.

Description

COUPLING MEMBER FOR BUILDINGS WITH TWO-PHASE VIBRATION DAMPING AND LOCKING FIELD OF INVENTION The present invention relates, in general terms, to the field of building structures and, more specifically, to vibration damping mechanisms for use in building structures, preferably having two-phase damping with a locking mechanism that mitigates damage. BACKGROUND OF THE INVENTION Modern buildings, which utilize common building components such as reinforced concrete shear walls, braced structural steel frames, structural steel or reinforced concrete moment frames, or combinations thereof, have inherently low damping properties that decrease with building height. Due to this low inherent damping, high-rise buildings, in particular, tend to be susceptible to excessive vibrations caused by dynamic loads. Excessive accelerations and torsional velocities can cause discomfort to occupants, while excessive displacements can damage structural and non-structural elements. For this reason, it is advantageous to provide additional sources of damping to control these excessive vibrations and reduce the overall response of the building to dynamic loads.These dynamic loads can include both those resulting from wind loads and seismic loads. The systems currently available for controlling displacements, speeds, and accelerations in such structures consist of passive systems such as supplementary dampers and vibration absorbers, as well as active systems. Passive dampers such as hysteretic, viscous, and viscoelastic dampers are currently used in common braced configurations and are activated under axial deformations. While this can be effective for adding damping to some structural configurations where, under this common braced configuration, the bracing elements experience significant axial deformations, they are less effective for other structural systems, such as those commonly used in high-rise buildings, where the primary mode of lateral deformation does not cause sufficient axial deformation in the common bracing elements to effectively activate such dampers.In order to increase the deformations enough to activate the shock absorbers, special configurations have been used that utilize lever braces or scissor braces to amplify the displacements. Vibration absorbers such as tuned mass dampers (TMDs) and tuned liquid dampers (TLDs) are also used to reduce the deflections, velocities, and accelerations of such structures under wind loads. These typically consist of a mechanical vibration system inserted into the top floor of buildings to maximize their effectiveness. This has the disadvantage of consuming some of the most valuable real estate within the building, as well as being expensive to design and construct. They also operate within a limited frequency range since they must be tuned to a single vibration mode. Active systems require an external power source, a driving force, and extensive hardware and software control systems. As a result, they are expensive to design and implement and are susceptible to power outages or control system failures. In PCT application no. sPCT / CA2006 / 000985, filed on June 16, 2006, a solution to the problems identified above with existing systems was proposed, entitled "Fork Configuration Dampers and Method of Using Same." The system in that application presents a configuration for damping systems in buildings to interconnect two structural elements that experience relative motion. The damping system in application '985 discloses a first set of plates attached to a first structural element, generally extending vertically, designed to resist lateral loads, and a second set of plates attached to a second structural element, generally extending vertically, designed to resist lateral loads. The vertically extending structural elements could be, for example, walls, columns, frames, or other vertical elements in a building.Each of the first and second plate sets comprises a plurality of substantially parallel, separate plate elements arranged such that the plate elements of the first plate set are interlocked with the plate elements of the second plate set. A damping material is provided to couple the first plate set to the second plate set. In this way, as the vertically extending structural elements experience relative movement due to the application of lateral loads to the building, the first and second plate sets shift in a vertical shear motion and act to dampen vibrations in the structure through the energy-dissipating material that resists displacement of the plates relative to each other. In PCT application no. sPCT / CA2012 / 050013, filed on January 11, 2012, entitled "Coupling Member for Damping Vibrations in Building Structures," an improvement to the aforementioned application was proposed. This improvement provides a damage mitigation mechanism to prevent damage to the damping member. However, the fuse requires modifications to the structural element itself, which has some implementation limitations. It would also be beneficial to provide damage mitigation functionality in elements other than the main structural member. SUMMARY OF THE INVENTION In one embodiment of the invention, a building structure is described that includes a plurality of elements extending from a ground surface, with at least a first element connected to a second element by a coupling member, the coupling member including a damping element for damping vibrations in the building structure; and a means for limiting the deformation of the damping element when the relative movement exceeds a maximum displacement at which damage to the damping element occurs. In one aspect of the invention, the damping element comprises a first and a second set of two or more plates each, wherein the plates of the first set are interlocked with the plates of the second set and separated from each other in a direction substantially parallel or perpendicular to the ground surface, and a damping material disposed between each plate of the plate sets, and the means for limiting deformation includes a plurality of grooves in the damping material and a plurality of bolt holes in the plates, each bolt passing through the corresponding bolt holes and grooves, so that, during normal operation, the bolts move freely in the grooves and, when the relative movement exceeds the maximum displacement, the bolts engage with walls of the grooves to prevent further deformation of the damping material. In one aspect of the invention, the damping material comprises a viscoelastic material; the damping element dampens vibrations as the damping element undergoes shear deformation as each plate of the plate assembly moves in a vertical direction under the resistance of the damping material. In one aspect of the invention, the slots and bolts are dimensioned and otherwise sized according to the maximum displacement. In one aspect of the invention, there is a static stiffness-enhancing structural member attached to an upper surface of the damping element. In one aspect of the invention, the static stiffness-enhancing member comprises a steel plate. In one aspect of the invention, at least one of a first and a second fusible member is connected to at least one of the first and second ends of the damping element, respectively. In one aspect of the invention, the fusible member is made of a material and is otherwise dimensioned or sized to exhibit semi-rigid behavior when the damping element experiences deformation due to loads below a predetermined load limit and to experience deformation when loads reach the predetermined load limit, such that the damping element is prevented from deforming due to loads above the predetermined load limit. In one aspect of the invention, the damping element comprises a first and a second set of two or more plates each, wherein the plates of the first set are interlocked with the plates of the second set and separated from each other in a direction substantially parallel or perpendicular to the ground surface, and a damping material disposed between each plate of the plate sets, and the means for limiting deformation includes a flange cantilever of the connecting steel elements, which prevents further deformation of the damping material. In one aspect of the invention, the damping element comprises a first and a second set of two or more plates each, wherein the plates of the first set are interlocked with the plates of the second set and separated from each other in a direction substantially parallel or perpendicular to the ground surface, and a damping material disposed between each plate of the plate sets, and the means for limiting deformation includes tension-limiting straps, which prevent further deformation of the damping material. BRIEF DESCRIPTION OF THE DRAWINGS Now, some realizations will be described, solely as examples, with reference to the attached figures, where: Figure 1 is a perspective view of a prior art damping element for use in building structures. Figures 2A and 2B are front and bottom views showing, respectively, a coupling member according to an embodiment of the invention. Figure 2C is a perspective view of the coupling element of Figures 2A and 2B. Figure 2D is a front view of the coupling member of Figures 2A and 2B that includes an optional static stiffness-enhancing member. Figures 3A and 3B are front and bottom views showing, respectively, a coupling member according to another embodiment of the invention. Figures 4A and 4B are front and bottom views showing, respectively, a coupling member according to another embodiment of the invention. Figures 5A and 5B are front and bottom views showing, respectively, a coupling member according to another embodiment of the invention. Figure 6 shows a projecting building configuration to which the embodiments of the invention can be applied. Figure 7 shows a building structure in which the embodiments of the invention can be applied. Figure 8 shows a front view of the coupling member including slots and bolts before locking according to one embodiment of the invention. Figure 9 shows a front view of the coupling member including slots and bolts when locking begins due to a damage incident according to an embodiment of the invention. Figure 10 shows a front view of the coupling member including slots and bolts when both ends are locked due to a damage incident according to an embodiment of the invention. Figure 11 shows a building structure to which the embodiments of the invention can be applied. Figure 12 is a detailed view of a coupling member from Figure 11. Figure 13 shows another building structure in which the embodiments of the invention can be implemented. Figure 14 is a detailed view of a coupling member from Figure 13. DETAILED DESCRIPTION OF THE INVENTION In the applicant's earlier PCT application no. sPCT / CA2006 / 000985, filed on June 16, 2006, entitled "Fork Configuration Dampers and Method of Using Same," the contents of which are incorporated herein by reference, a damping system for use in building structures was disclosed, which included a damping element as shown in Figure 1. As illustrated, the damping element 10 comprises two assemblies 14, 16 of two or more plates 20, spaced apart in a direction substantially parallel to the ground surface, and a damping material 30 disposed between each plate 20 of the plate assemblies. In practice, the plate assemblies are interlocked, and these plates have ends 40 rigidly connected to vertical elements 50 of the building structure.The vertical elements 50 resist lateral loads applied to the building structure and move relative to each other when significant loads are applied. The plates 20, as well as the damping material 30, placed between them, undergo shear deformation as the vertical elements 50 move relative to each other and, consequently, by virtue of the damping material, provide damping in the building structure as the steel plates 20 move relative to each other. The damping material is preferably a viscoelastic material.The improvements described in this application apply, preferably, to the system described in the aforementioned PCT international patent application, but can also be applied to other damping systems used in building structures and, particularly, to tall building structures where vibrations caused by lateral loads applied to the building structure in question. The embodiments of the invention relate, in particular, to improvements in systems that dampen vibrations in building structures and, specifically, to systems that provide damping for vibrations caused by lateral loads applied to a building structure and resisted by vertical elements. Likewise, the embodiments described herein are particularly applicable to damping systems that include fail-safe mechanisms for extreme loading conditions which, in the absence of the elements disclosed herein, would result in significant damage to the damping system, for example, during a seismic event.The various embodiments of the invention, as described in detail below, provide solutions for making damping systems in building structures more robust, more easily repairable and replaceable, and for limiting the damping element from reaching its point of damage and thus avoiding permanent damage in the event of strong vibrations or catastrophic load events such as earthquakes. Other benefits and advantages of the invention described herein will also be outlined below and will be apparent to a person skilled in the art. In particular, the invention provides one or more fusible members that act as a second stage of damping and are connected to the damping element.The fusible member, as described in more detail below, is designed, sized, and otherwise dimensioned to exhibit semi-rigid behavior when the damping element experiences deformation due to lateral loads below a predetermined load limit, and to undergo deformation without a substantial increase in the loads carried by the fusible and damping elements when the lateral loads exceed that predetermined load limit, such that the damping element is prevented from deforming beyond its predefined deformation limit. In this description, the fusible member is referred to as being activated when the lateral loads exceed the predetermined load limit in this context. The fusible member represents a second stage of the structure's damping capabilities. The predetermined load limit is preferably selected at a load limit below which a damage incident occurs. In practice, lateral loads applied to the building structure are resisted by the vertical elements. These lateral loads result in deformations, particularly shear deformations, in the damping system that acts as a coupling member between the vertical elements. At a given damping system load, shear or other deformation in the damping system results in a damage incident. For the purposes of this application, a damage incident is defined as one that would cause permanent, near-permanent, or similar damage that cannot be repaired in situ to the damping element or that renders the damping system ineffective in providing damping to the structure.Preferably, the damage incident is one or more of the following: tearing of the damping material, detachment of the damping material from a plate to which the damping material is attached, failure of a plate forming part of the damping element, failure of a means for connecting elements in the damping element, failure of a weld connecting the damping element or the column element, and failure of a connecting means for the coupling member, or a combination thereof. Other damage incidents or failure modes are also considered, including, but not limited to, failure of the vertical elements to which the dampers are attached.Therefore, the fusible member as described herein undergoes deformation after a predetermined activation load is reached, without any substantial increase in the load carried by the fusible member and / or the damping element, thus protecting the coupling member from all anticipated damage incidents. In order to implement a fusible member as described herein, the applicants provide one or more parallel-connected beam members which, in combination, exhibit semi-rigid behavior when loaded below a predetermined load limit. Optionally, the beam members also include a stiffener to stabilize them under high load conditions. Having thus described the operating principles of the invention in general terms, several specific embodiments of the invention will now be described. Referring now to Figures 2A, 2B, and 2C, an embodiment of the invention is shown, comprising a cross-section of a first 205 and a second 210 vertical elements, which are two of a plurality of vertical elements extending vertically from a ground surface (not shown). For the purposes of this application, the terms "vertical" and "vertically" are understood to be used in their common sense with respect to building structures, i.e., in a direction generally perpendicular to the ground surface. Additionally, the term "horizontally," when used, refers to a direction that is generally parallel to the ground surface. A coupling member 215 connects the first vertical element 205 to the second vertical element 210.The coupling member 215, as described herein, can function to replace or be used in place of rigid coupling members traditionally used in building structures. The coupling member 215 preferably includes a damping element 225 for damping vibrations in the building structure resulting from the relative movement between the first 205 and second 210 vertical elements due to lateral loads applied to the building structure. An exemplary embodiment of a damping element 225 according to the invention is described below. Regardless of the particular implementation of the damping element, the damping element will have a defined damage threshold determined according to design constraints and the loads typically encountered during operation that result in deformation of the damping element due to the relative movement between the vertical elements 205 and 210.Once the load level on the damping element reaches a predetermined limit, due to the high loads applied to the building structure, the damping element, in the absence of the fusible members according to the invention, as described below, will be permanently deformed, damaged, or otherwise rendered unusable. This would make the damping element ineffective for subsequent load cycles. To address this problem, the applicants further provide an optional first fusible member 220 and a second fusible member 230 connected to a first end 240 and a second end 250 of the damping element 225, respectively. The fusible members 220 and 230 are selected from a material and are sized and otherwise dimensioned to exhibit semi-rigid behavior when the damping element 225 experiences deformation due to loads below a predetermined load limit, and to activate and thus experience deformation when the loads reach the predetermined load limit without any substantial increase in the load carried by the fusible member and the damping element 225, thereby preventing the damping element 225 from deforming due to loads above the predetermined load limit.As described above, the predetermined load limit is that at which a damage incident occurs that would render the damping element 225 unusable for continued use, depending on any number of factors. A first connecting member 260 is provided to connect the first fusible member 220 to the first vertical element 205 and, similarly, a second connecting member 270 is provided to connect the second fusible member 230 to the second vertical element 210. The connecting members 260, 270 preferably provide a semi-rigid connection with the vertical elements 205, 210, such that any possible movement caused by any bending moments in the connecting members 260, 270 is completely restrained before the fusible member is activated. The fuse members 220 and 230 preferably include a beam portion 280 and, optionally, a stiffener portion 290. The stiffener portion 290 is designed, sized, and otherwise dimensioned to functionally connect to the beam portion 280 and to provide stabilizing support to the beam portion 280 when the loads applied to the vertical members reach predetermined loads. Consequently, when the fuse members 220 and 230 are activated, the stiffener portion 290 acts to provide additional deformation capacity to the fuse members 220 and 230 themselves. This occurs without any substantial increase in the loads carried by the fuse and the damping element. In the illustrated embodiment, the stiffener portion 290 may be a reinforcing member 290 that is connected to the beam portion 280 and arranged parallel to the ground such that the stiffener portion 290 provides stability against buckling of the beam portion 280 while yielding in flexure when the applied lateral loads reach and / or exceed the predetermined load. For clarity, where reference is made throughout the description and claims to the applied loads reaching the predetermined load, the predetermined load is that at which loads below this value do not result in damage to the damping element or its related connections that would render the damping element unusable. The types of damage contemplated have been set out above, but are not limited to them. The damping element 225 preferably includes two plate assemblies 212, 213, each having at least two, and more preferably a plurality of, plates separated horizontally. The plate assemblies 212, 213 are interlocked and have an overlap region 214 where a portion of half the plates of the assembly overlaps. In this overlap region 214, a damping material 216, preferably a viscoelastic material, is provided and attached to each plate on each side of the plates, as illustrated. On each side of the overlap region 214, connecting means 218 are provided that hold the plate assembly together and the damping material 216 compressed in the overlap region 214. As illustrated, the connecting means 218 are preferably bolts. As shown in Figure 2D, an optional static stiffness-enhancing member 232 can be attached to a top surface 234 of the plate assemblies 212, 213. In a preferred embodiment, the stiffness-enhancing member 232 is a plate, and preferably a steel plate. Other static stiffness-enhancing members 232 are also contemplated, including, but not limited to, angle sections, U-sections, and other members that can perform the desired function as described. During operation, the plate member 232 serves to increase the static stiffness of the damping element 215. In the preferred embodiment, the plate 232 increases the static stiffness of the damper such that, under static lateral loads caused by wind pressure on the building, which are also applied in combination with dynamic lateral loads, the structure is stiffer and undergoes less deformation. The static stiffness-enhancing member 232, in any of its structural forms described herein, may be connected to the top and / or bottom of the coupling member. One side of member 232 is preferably connected to one of the connecting elements, and the other side of the structural element is connected to another connecting member. For clarity, member 232 is not connected to the plate assemblies 212 and 213, which are bonded to the viscoelastic material. In another embodiment, member 232 may be embedded directly into the vertical elements or walls, a short distance above and below, respectively, but is not connected to the damping element. During operation, this also enhances the coupling effect under static loads.Additionally, the increase in the overall stiffness of the structure caused by the installation of the static stiffness-enhancing member 232 also reduces the vibration period of the structure as a whole, which, in turn, reduces the dynamic effects of wind loading on the structure. The following section describes various other implementations of a fusible member. Elements that correspond directly to those described and illustrated with respect to Figures 2A-2D are numbered accordingly in hundreds for the respective figure number, but are not described in further detail except as necessary to describe particular aspects, variations, or embodiments of the invention. Referring below to Figures 3A-3B, fusible members 320 and 330 are shown, formed by the beam portion 380 and the stiffener portion 390. In this embodiment, the stiffener portion 390 is at least one, and preferably a plurality of, stiffener members 390 connected to the web and between the flanges of the fusible member, and arranged in parallel with the vertical elements 305, 310 such that the stiffener portion 390 provides stability against buckling in the fusible member when the applied lateral loads exceed the predetermined load. Referring now to Figures 4A-4B, fusible members 420 and 430 are shown. The fusible members 420 and 430 consist of semi-rigid plates 480, secured (or otherwise attached) to plates extending from the plate assemblies in the damper by connecting means 490. As illustrated, the connecting means 490 are bolts that prevent the plates from sliding relative to the semi-rigid plates 480. When the predetermined friction force limit is reached, the plates slide and the semi-rigid plates move relative to each other. Consequently, the fusible element, in this embodiment, is activated by the sliding of the bolted connection, and thus the bolted connection itself forms the fusible mechanism in this embodiment. Horizontal or rotational movement of the bolts can be admitted through the connection by means of an inclined connecting portion. Referring now to Figures 5A-5B, another embodiment of the invention is shown in which the fusible members 520 and 530 are formed by an axial force-limiting member 595 that runs through a conduit 590 embedded in the vertical elements 505 and 510 and connected to the end plate connector 560. During operation, the axial force-limiting members 595 limit the axial forces transmitted to the damper when the predefined load limit is reached. The axial yielding of the members 595 limits the loads imparted to the damping system. The invention provides various means for connecting the various fusible members described above to the vertical elements. Advantageously, in some embodiments, as will become evident from their respective descriptions below, the connection means are preferably provided to allow the partial or complete removal, repair, and / or replacement of the coupling members after a high-load incident in which the force-limiting members are activated upon reaching the predefined force limit. For example, referring to Figure 6, a projecting building configuration is shown, where a central building vertical 610 has a plurality of separate exterior vertical elements 605, the coupling member 615 being contiguous to each of the exterior vertical elements 605 and the central building vertical 610. Various floors 620 in the building structure are also shown. It will be evident that the coupling member 615 is only illustrated schematically and could be any of the coupling members described with respect to Figures 2A-2D to 5A-5B. Likewise, the connecting means for coupling to the verticals 605, 610 can be as described herein. Figure 7 shows a general implementation of the invention in which coupling members 725 are used to connect two verticals 705, 710 in a building structure. Referring now to Figure 8, a preferred embodiment of the invention is shown, which can be applied to any of the embodiments described above with or without the fusible element. Figure 8 shows a front view of the coupling member including slots and bolts before locking according to one embodiment of the invention. According to one embodiment of the present invention, a viscoelastic coupling damper (VCD) for a building structure includes a plurality of vertical elements extending vertically from a ground surface, at least one of said vertical elements being connected to a second of said vertical elements by means of a coupling member.The coupling member comprises: a damping element 826 for damping vibrations in the building structure resulting from relative motion between the first and second vertical elements due to lateral loads applied to the building structure, the damping element undergoing deformation due to this relative motion, at least one first end 822 being connected to at least one second end 824 of the damping element 826. Similar to Figures 2A-2D, for example, the damping element 826 preferably includes two sets of plates having at least two, and more preferably a plurality of, plates separated in the horizontal direction. The plate sets are interlocked and have an overlapping region where a portion of half the plates of the set overlaps.In this overlap region, a damping material, preferably a viscoelastic material, is provided and attached to each plate on each side, as illustrated. Connecting means are located on each side of the overlap region, holding the plate assembly together and the damping material compressed within the overlap. As illustrated, the bolt holes shown collectively as 822 and 824 provide a means of connection. Columns 810 of the building structure are shown in the typical implementation. On each side of the overlap region, connecting means 818, 820 are located, which hold the plate assembly together and the damping material compressed within the overlap region. The arrangement of slots and bolts can function to control / prevent deformation of the building structure with or without the implementation of fusible members. In an exemplary embodiment of the present invention, damage is controlled, or deformation of the damper beyond the point of permanent deformation is prevented, by a plurality of slits 818 and a plurality of bolts 820 extending through the slits. Slits 818 are provided in the viscoelastic material. Holes through which the bolts 820 pass are provided in the cover plates 816 on the front and rear sides of the overlapping regions. During normal operation, the viscoelastic member is free to deform and dampen vibrations as described herein and as described in the two PCT applications set forth in the Background. Referring now to Figures 9 and 10, the front and rear views of the coupling member are shown as extreme loads, such as those from an earthquake, are applied to the structure. The viscoelastic member experiences maximum displacement until bolt 820 moves to the point of engagement with an inner wall of the slot 820. At this point, further deformation of the damper and viscoelastic material is prevented, and the forces are transmitted from the steel plate encapsulating the viscoelastic material, through the bolts, and to the coupling member itself. In this way, the damper is limited to severe failure. In the case of a vertical arrangement of the viscoelastic coupling damper, the slot is perpendicular to the VCD, and the bolts move in the vertical direction (as illustrated in Figure 11).In the case of a horizontal arrangement of the viscoelastic coupling damper, the gap is perpendicular to the VCD, and the bolts move in the horizontal direction. Furthermore, the size of the gap can also be varied depending on the requirements of the building structure. This means that if the building structure is constructed in an area of ​​probable low-amplitude earthquakes (low risk), the size of the gap can be kept smaller. Conversely, if the building structure is constructed in an area of ​​high seismic risk, where the probability of a high-amplitude earthquake is higher, then the size of the gap can be larger. The plurality of bolts 818 moves in the vertical direction (with respect to the coupling member) in the respective gaps 820 to prevent damage to the structure. The gap 926 illustrates that some degree of deformation has occurred.As shown in Figure 10, the damping element 826 has reached its damage incident limit and, consequently, the blocking state is reached. In embodiments where a fuse is also used, the fuses 812 and 814 undergo deformation to prevent the damping element 826 from deforming further after the blocking state is reached. In the exaggerated view shown, the plates 816 in the plate assembly on each side of the damping material have been displaced to a maximum amount in the vertical direction. Although the invention, as described above, relates to a coupling member for connecting two vertical elements in a building structure, the applicant notes that the coupling member, as described herein, can be used or otherwise applied to various implementations where vibration damping due to lateral loads may be required. In this regard, the term "vertical elements," as used throughout this description, should be interpreted broadly to include any structural elements that provide support against lateral loads applied to the building structure. Building structures of various types can benefit from the vertical element as disclosed herein. EXAMPLES The behavior of a building during an earthquake depends on several factors, including adequate lateral stiffness, strength, and ductility, as well as simple and regular configurations. Viscoelastic coupling dampers were used in building structures at different locations—vertically or horizontally—depending on the building type, such as a low-rise or high-rise reinforced concrete structure. Furthermore, a blocking test was performed under different configurations. This blocking test involved applying a shear force of 1000 kN to 2000 kN using actuators. During the blocking tests, the displacement of the viscoelastic coupling damper in the building structure ranged from 50 mm to 150 mm. The hysteresis curve of the VCD indicated that as the shear forces increased, the shear displacement also increased. EXAMPLE 1 Figure 11 shows a building structure 1110 to which the embodiments of the invention can be applied in a vertical arrangement. The viscoelastic coupling member 800 is positioned between two floors. This particular arrangement is useful for low-rise building structures or reinforced concrete buildings. In the event of earthquakes or gales, the force and displacement are always perpendicular to each other. In the arrangement shown in Figure 11, the force will be parallel to the ground, and the displacement will be perpendicular to the direction of the force. Figure 12 shows a detailed two-story view of Figure 11, where the numbering is as described above with respect to Figure 8. EXAMPLE 2 In another embodiment of the present invention, as shown in Figures 13 and 14, the viscoelastic coupling member can be arranged horizontally to the building structure. In this arrangement, the viscoelastic coupling member can be arranged in a beam configuration, meaning it is positioned between two beam portions. In another arrangement, the viscoelastic coupling member can be positioned in a projecting configuration, located between the building structure and the projecting column (which supports the building structure). This particular arrangement is useful for high-rise building structures. The force will be in the direction perpendicular to the ground, and the displacement will be perpendicular to the direction of the force, meaning it will be a horizontal movement of either the building structure or the viscoelastic coupling member. The invention also provides a method of connecting vertical elements in a building structure as previously described, by providing a coupling member according to any one of the various embodiments of the invention and by rigidly connecting two vertical elements in a building structure with the coupling member. While the invention can be implemented using various damping members, surprising results have been obtained with the combination of the damping member as described in the preferred embodiments, where the risk of permanent deformation due to high shear forces or moments is most relevant. Specifically, in the damping member of Figures 2A, 2B, 20, and 8, where a plurality of plates are connected with an intervening damping material, when subjected to excessive shear or moment forces, or other stresses, forces beyond that threshold result in a damage incident. Generally speaking, a damage incident would also include one in which the failure of the coupling element itself could be catastrophic.As explained above, a damage incident is one that would cause permanent, near-permanent, or similar damage that renders the damping element ineffective. Such damage incidents include, but are not limited to, one or more rips of the damping material in the damping element, detachment of the damping material from a plate to which the damping material is attached, failure of a plate that is part of the damping element, failure of a means for connecting elements in the damping element, failure of a weld connecting the damping element or column element, failure of the vertical elements and failure of a connecting means for the coupling member, failure of the vertical elements to which the damping device is attached, or a combination thereof. As a person skilled in the art will appreciate, although the fusible element does limit the forces applied to the damping element, there is still a small increase in force as the yielding element deforms, primarily due to the strain hardening of the steel. This increase is very small and can be considered negligible for the purposes of this invention. The scope of the claims should not be limited by the preferred embodiments set out in the description of preferred embodiments or in the examples, but should be given the broadest interpretation compatible with the description as a whole.

Claims

1. A building structure comprising a plurality of elements extending from a ground surface, with at least a first of said elements connected to a second of said elements by means of a coupling member, said coupling member comprising: a damping element for damping vibrations in said building structure; and a means for limiting the deformation of said damping element when said relative movement exceeds a maximum displacement at which damage to said damping element occurs.

2. The building structure according to claim 1, wherein said damping element comprises a first and a second set of two or more plates each, wherein the plates of said first set are interlocked with the plates of said second set and separated from each other in a direction substantially parallel or perpendicular to the ground surface, and a damping material disposed between each plate of said plate sets, and said means for limiting deformation includes a plurality of grooves in said damping material and a plurality of bolt holes in said plates, each bolt passing through the corresponding bolt holes and grooves, whereby, during normal operation, the bolts move freely in said grooves;and, when said relative movement exceeds the maximum displacement, the bolts engage with the walls of the slots to prevent further deformation of said damping material.

3. The building structure according to claim 2, wherein said damping material comprises a viscoelastic material; said damping element dampening vibrations as said damping element undergoes shear deformation as each plate of said plate assembly moves in a vertical direction under the resistance of said damping material.

4. The building structure according to claim 2, wherein said slots and said bolts are dimensioned and otherwise sized according to said maximum displacement.

5. The building structure according to claim 2, further comprising a static stiffness-enhancing structural member attached to an upper surface of said damping element.

6. The building structure according to claim 7, wherein said static stiffness-enhancing member comprises a steel plate.

7. The building structure according to claim 1, wherein at least one of a first and a second fusible member is connected to at least one of the first and second ends of said damping element, respectively.

8. The building structure according to claim 7, wherein said fusible member is made from a material and is otherwise dimensioned or sized to exhibit semi-rigid behavior when said damping member experiences deformation due to loads below a predetermined load limit and to experience deformation when loads reach said predetermined load limit, such that said damping member is prevented from deforming due to loads above said predetermined load limit.

9. The building structure according to claim 1, wherein said damping element comprises a first and a second set of two or more plates each, wherein the plates of said first set are interlocked with the plates of said second set and are separated from each other in a direction substantially parallel or perpendicular to the ground surface, and a damping material disposed between each plate of said plate sets, and said means for limiting deformation includes a flange overhang of the connecting steel elements, which prevents further deformation of said damping material.

10. The building structure according to claim 1, wherein said damping element comprises a first and a second set of two or more plates each, wherein the plates of said first set are interlocked with the plates of said second set and are separated from each other in a direction substantially parallel or perpendicular to the ground surface, and a damping material disposed between each plate of said sets of plates, and said means for limiting deformation includes tension-limiting straps, which prevent further deformation of said damping material.

Images