Mechanical couplings for dissipation of seismic energy

Abstract

Mechanical couplings (and braces including such couplings) are provided for seismic energy dissipation. The couplings may be integrated into building / structure construction to avoid irreparable damage due to major seismic events that would otherwise warrant total replacement of buildings / structures. The couplings include interconnected coupling members that are operable as a mechanical coupling to dissipate seismic energy by relative movement of the members due to friction therebetween. In certain embodiments, the coupling members are joined to form a rotational element that operates like a hinge. Fasteners are used to apply compression and adjust friction characteristics. Multiple dissipative braces may be arranged to a structural element, such as a column of a rocking column system of a structure or a frame of a moment-braced frame, to form a dissipative brace system. In a seismic event, the coupling acts as a mechanical fuse to dissipate energy via friction and protecting the structure.

Description

ATTORNEY DOCKET NO. 10859.051 W01-GSBMECHANICAL COUPLINGS FOR DISSIPATION OF SEISMIC ENERGYCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority, under 35 U.S.C. §119(e), of U.S. Provisional Patent Application No. 63 / 750,647, filed January 28, 2025, the entire disclosure of which is hereby incorporated herein by reference.FIELD OF THE INVENTION

[0002] The present invention relates generally to construction of buildings and other structures, and more particularly, to mechanical coupling elements that may be incorporated into buildings or other structures for seismic bracing purposes, and that are configured to dissipate seismic energy during a seismic event.DISCUSSION OF RELATED ART

[0003] In geographic regions with high seismic activity, buildings and other structures (e.g., bridges, etc.) are at risk of damage due to seism ic / earthquake activity. In the event of damage to such structures, the structures must often be replaced or repaired. Repairs can be extensive and very expensive, and are nonstandard tasks involving assessment of unique damage conditions, development of plan, and application-tailored development of solutions and installation plans.

[0004] Techniques and structural systems have been developed to minimize damage or even fully protect structures during extreme seismic events. Such technologies include seismic isolation, passive and semi-active damping devices, rocking / self-centering systems, viscous and friction dampers, and advanced bracing systems. However, their use in buildings is limited due to their high cost and proprietary nature. Therefore, the majority of buildings and structures are designed as ordinary, intermediate, or special seismic force-resisting systems based on desired ductility levels. Ordinary systems are designed for higher force demands and to exhibit limited inelastic deformation (limited ductility) without total collapse, whereas special systems exhibit inelastic deformation (nonlinear deformation) thatATTORNEY DOCKET NO. 10859.051 W01-GSB enables seismic energy dissipation without strength loss. Examples of these special systems include special moment frames and special concentric braced frames (CBFs). Such special systems are economical, meet both serviceability and strength limit states, fit performance-based design approaches, and attain sufficient ductility to prevent collapses; however, they suffer irreparable damage that warrants extensive and expensive repairs or a total replacement of buildings / structures. These damage states include extensive yielding, inelastic buckling, and brace rupture from low-cycle fatigue due to the seismic activity.

[0005] Accordingly, seismic force-resisting systems represent critical infrastructure components designed to mitigate structural damage during extreme earthquake events. In certain applications, contemporary rocking structures with external energy dissipators offer promising solutions for achieving performancebased earthquake engineering objectives, addressing fundamental challenges of ductility, energy absorption, and structural resilience.

[0006] As a result of the ductility-based seismic design approach, concrete bridge columns and building walls can experience large residual displacement under seismic events. Large residual drifts can result in significant damage, making it difficult to repair or requiring total structure replacement. To address large residual drifts, columns and walls can be designed as low-damage structures to “rock” during seismic events and return to their original position after the earthquake through self-centering mechanisms. Rocking systems can range from rigid body rocking columns, where the self-weight of the column and supported structure enable a certain degree of self-centering, to dissipative controlled rocking (DCR) systems. DCR systems are hybrid systems that integrate self-centering posttensioned or pre-tensioned stands or shape memory alloys with energy dissipation devices to significantly reduce residual deformations and enhance energy dissipation. Internal dissipation devices were utilized in the DCR systems, where reinforcing steel bars improved the post-yield stiffness of the structure while reducing the residual displacement. However, while internal energy dissipation (ED) devices have proven to be effective and easy to install in the rocking columns, the reinforcing bars inside of the column would often be damaged due to buckling and low-cycle fatigue. Because the reinforcing bars are placed internally, inspection and repair could be difficult due to the absence of concrete damage at the rocking interfaces.ATTORNEY DOCKET NO. 10859.051 W01-GSB

[0007] Concentric braced frames (CBFs) are a common type of braced frame that are commonly used in the construction of structures in geographic regions with high seismic activity. Figs. 1 and 2 illustrate exemplary conventional CBF brace systems 100 including a frame 110 made up of multiple frame members 112, 114, 116 including a structural brace member 120. Examples of CBF systems include diagonal bracing (e.g., as in the example of Fig. 1), X-bracing, multi X-bracing, V-bracing and inverted V-bracing (as shown in the example of Fig. 2), among others. The braces 120 are typically arranged in a concentric configuration through the alignment of the bracing elements’ axes with vertical columns and horizontal beam axes. This may be achieved by way of mounting of brackets / flanges / plates 130 and mechanical fasteners (such as nuts / bolts / rivets, etc.) or welds for mechanically interconnecting and coupling the braces 120 with other members 112, 114, 116 of the frame 110 of the brace system 100.

[0008] CBFs can dissipate seismic energy and tend to be more economical than moment-resisting frames and eccentric braced frames (EBFs). As above, ordinary CBFs provide limited inelastic deformation capacity in their members and connections, and their primary function is to provide sufficient stiffness and resist lateral forces through their tensile and compressive strength. With low inelastic deformation, they are designed using a higher seismic force level (lower value of response modification factor, R) to account for their limited system ductility. With their relatively simple design and construction procedures, they can be an attractive choice for smaller buildings and nonbuilding structures but are less desirable in larger buildings or with a higher seismic performance objective.

[0009] Special CBFs provide significant inelastic deformation capacity primarily through brace buckling in compression and yielding in tension. The term “special” refers to a specific seismic design category established by the American Society of Civil Engineers (ASCE7-22). They are the most-used braced frame systems for seismic design today because their strength and stiffness economically satisfy serviceability design limit states. Special concentric braced frames (SCBFs) are economical, meet both serviceability and strength limit states, fit performancebased design approaches, and attain sufficient ductility to prevent collapses.However, SCBFs sustain extensive damage following major seismic events that is irreparable and that warrants a total replacement of the associated building or other structures.ATTORNEY DOCKET NO. 10859.051 W01-GSB

[0010] What is needed is a novel approach to seismic energy dissipation and building / structure construction that avoids irreparable extensive damage warranting total replacement of the buildings / structures in response to major seismic events, such as earthquakes.SUMMARY

[0011] The present invention provides a novel approach to seismic energy dissipation and building / structure construction that avoids irreparable extensive damage to the structure warranting total replacement of the buildings / structures in response to major seismic events. More particularly, the present invention provides a mechanical coupling, and a dissipative brace and brace system comprising a mechanical linkage including a mechanical coupling, and structures including dissipative braces and / or brace systems, that are operable to dissipate seismic energy due to loading during a seismic event, to avoid irreparable damage due to major seismic events that would otherwise warrant total replacement of buildings / structures. The mechanical couplings, and dissipative braces and brace systems, are configured to include coupling members that are mechanically interconnected to form a mechanical coupling that is operable to dissipate seismic energy by relative movement of the coupling members due to friction therebetween. Accordingly, these elements are configured to have mechanical couplings that are operable to dissipate energy and avoid permanent deformation / buckling / damage that would otherwise result in permanent deformation / buckling and permanent damage in a conventional structure or bracing system.

[0012] In certain embodiments, the coupling members are mechanically interconnected by a mechanical fastener, such as a bolt, to form a pivotable mechanical coupling, such that the coupling members may exhibit relatively rotational motion therebetween, somewhat like a hinge. Torque on the bolt / nut and / or tension on the mechanical fastener may be applied to modify the force resisting characteristics of the mechanical coupling - e.g., to cause resistance relative motion up to a certain threshold, and to permit relative motion above the threshold, the relative motion dissipating seismic energy due to friction between the coupling members. As desired, the coupling members may have modified surfaces to increase or decrease friction due to relative motion therebetween, and / or may haveATTORNEY DOCKET NO. 10859.051 W01-GSB supplemental structures / materials designed to augment or otherwise modify energy dissipation resulting from relative motion therebetween.

[0013] Accordingly, the present invention provides bracing elements configured to permit damage-free buckling, during compression and / or tension cycles, at deliberately designed hinges, e.g., when the bracing elements exceed their breaking load in compression, without affecting their ability to resist tension forces. This damage-free buckling / buckling permissibility concept applied to steel has multiple advantages over conventional SCBFs, namely, elimination of inelastic buckling deformation in steel members; reduction of adverse effects of low-cycle fatigue by eliminating loading cycles in compression; and repairability for both new construction and existing SCBFs by means of replacement of bracing elements. For example, individual coupling elements may be replaced without replacing the entire structure or bracing system and / or seismic energy dissipation capacity may be restored after a seismic event by retightened fasteners loosened during a seismic event. Bracing elements providing such buckling permissibility are applied not only in SCBFs but also in structural systems such as bridge braces and external dissipation devices in self-centering structures, as discussed further herein.

[0014] In this manner, the mechanical couplings, and dissipative braces and brace systems, act somewhat like a mechanical fuse, as an intended point of energy dissipation in the event of seismic activity, thereby protecting the remainder of the brace systems and / or structures.BRIEF DESCRIPTION OF THE FIGURES

[0015] An understanding of the following description will be facilitated by reference to the attached drawings, in which:

[0016] Fig. 1 is a perspective view of an exemplary conventional CBF brace system including a conventional CBF brace member representative of the prior art;

[0017] Fig. 2 is a perspective view of an alternative exemplary conventional CBF brace system including a conventional CBF brace member representative of the prior art;

[0018] Fig. 3 is a perspective view of an exemplary dissipative brace system in the nature of a resilient dissipative bracing system (RDBS) in accordanceATTORNEY DOCKET NO. 10859.051 W01-GSB with the present invention, including an exemplary mechanical coupling and mechanical linkage;

[0019] Fig. 4A and 4B are plan and perspective views, respectively, of an exemplary mechanical linkage in accordance with an exemplary embodiment of the present invention, shown in a generally-linear orientation;

[0020] Figs. 4C and 4D are plan and perspective views, respectively, of the exemplary mechanical linkage of Figs. 4A and 4B, shown in an angled orientation;

[0021] Fig. 5A is a plan view of another mechanical linkage in accordance with an alternative embodiment of the present invention;

[0022] Fig. 5B is a partial side view of the mechanical linkage of Fig. 4A, showing a portion removed for clarity to illustrate an exemplary mechanical fastener;

[0023] Figs. 6A-6C show a stress distribution on an exemplary coupling in a longitudinal direction, a stress distribution as a function of cross-section at different radii, and a shear stress distribution on the surface at rc.

[0024] Figs. 7A and 7B are perspective views of an exemplary rocking column structural element of an exemplary structure, showing exemplary dissipative brace systems in a generally-linear configuration and angled configuration, respectively;

[0025] Figs. 8A-8C are elevational views showing the exemplary generally-linear configuration dissipative brace system of Fig. 7A in multiple rocking states;

[0026] Figs. 9A-9C are elevational views showing the exemplary angled configuration dissipative brace system of Fig. 7B in multiple rocking states;

[0027] Figs. 10A-10B illustrate theoretical hysteresis of the exemplary dissipative systems of Figs. 21 A and 21 B, respectively;

[0028] Figs. 11 A-11 B show exemplary structures incorporating exemplary dissipative brace systems in an angled configuration;

[0029] Figs. 11 C-11 D show exemplary structures incorporating exemplary dissipative brace systems in a generally-linear configuration;

[0030] Figs. 12A-15 show exemplary structures incorporating exemplary dissipative brace systems in an angled configuration;

[0031] Fig. 16 shows exemplary dissipative braces in angled configurations in braced frame dissipative brace systems;ATTORNEY DOCKET NO. 10859.051 W01-GSB

[0032] Fig. 17 shows exemplary dissipative braces in generally-linear configurations in braced frame dissipative brace systems;

[0033] Figs. 18-19 show exemplary dissipative braces in generally-liner and angled configurations in rocking-type dissipative brace systems, respectively;

[0034] Figs. 20-21 show exemplary mounting components of the rockingtype dissipative brace systems of Figs. 18 and 19;

[0035] Figs. 22A-22D show an exemplary dissipative brace including a mechanical linkage comprised of mechanical couplings in accordance with the present invention, and exemplary force-displacement data as a function of bolt torque;

[0036] Fig. 23 shows an exemplary dissipative brace system used for exemplary testing purposes;

[0037] Fig. 24 illustrates an exemplary load cycle data for an exemplary dissipative brace including a mechanical linkage comprised of mechanical couplings in accordance with the present invention;

[0038] Fig. 25 is a graph illustrating exemplary experimental forcedisplacement data for an exemplary dissipative brace including a mechanical linkage comprised of mechanical couplings as a function of bolt torque in accordance with the present invention;

[0039] Fig. 26 illustrates a specimen naming convention for dissipative brace specimens;

[0040] Fig. 27 is illustrates friction energy of an exemplary brace under different torque levels, highlighting a relationship between applied torque and friction energy;

[0041] Figs. 28A and 28B illustrate an exemplary model of rotational friction behavior as a function of axial force and axial displacement for an exemplary dissipative brace including a mechanical linkage comprised of mechanical couplings in accordance with the present invention for various mechanical linkage configurations;

[0042] Figs. 29A-29D illustrate a comparison between the theoretical force-displacement bounds of Figs. 22A-22D and actual experimental force displacement of Fig. 25 as a function of bolt torque.ATTORNEY DOCKET NO. 10859.051 W01-GSB

[0043] Figs. 30A-31 C illustrate exemplary force-displacement data for exemplary cyclic loading of exemplary mechanical linkages comprised of mechanical couplings in accordance with the present invention;

[0044] Fig. 32 illustrates exemplary cyclic force-displacement data for an exemplary mechanical linkage comprised of mechanical couplings in accordance with the present invention;

[0045] Fig. 33 illustrates exemplary energy dissipation data for an exemplary mechanical linkage comprised of mechanical couplings in accordance with the present invention; and

[0046] Figs. 34A-34C are partial, exploded, and assembled perspective views, respectively, of an exemplary mechanical coupling including a supplementary dissipative mechanism in accordance with an alternative embodiment of the present invention.DETAILED DESCRIPTION

[0047] The present invention provides a novel approach to seismic energy dissipation and building / structure construction that avoids irreparable extensive damage to the structure warranting total replacement of the buildings / structures in response to major seismic events. More particularly, the present invention provides a mechanical coupling, and a dissipative brace and brace system comprising a mechanical linkage including a mechanical coupling, and structures including dissipative braces and / or brace systems, that are operable to dissipate seismic energy due to loading during a seismic event, to avoid irreparable damage due to major seismic events that would otherwise warrant total replacement of buildings / structures. The mechanical couplings, and dissipative braces and brace systems, are configured to include coupling members that are mechanically interconnected to form a mechanical coupling that is operable to dissipate seismic energy by relative movement of the coupling members due to friction therebetween. Accordingly, these elements are configured to have mechanical couplings that are operable to dissipate energy and avoid permanent deformation / buckling / damage that would otherwise result in permanent deformation / buckling and permanent damage in a conventional structure or bracing system.

[0048] In certain embodiments, the coupling members are mechanically interconnected by a mechanical fastener, such as a bolt, to form a pivotableATTORNEY DOCKET NO. 10859.051 W01-GSB mechanical coupling, such that the coupling members may exhibit relatively rotational motion therebetween, somewhat like a hinge. Torque on the bolt / nut and / or tension on the mechanical fastener may be applied to modify the force resisting characteristics of the mechanical coupling - e.g., to cause resistance relative motion up to a certain threshold, and to permit relative motion above the threshold, the relative motion dissipating seismic energy due to friction between the coupling members. As desired, the coupling members may have modified surfaces to increase or decrease friction due to relative motion therebetween, and / or may have supplemental structures / materials designed to augment or otherwise modify energy dissipation resulting from relative motion therebetween.

[0049] Accordingly, the present invention provides bracing elements configured to permit damage-free buckling, during compression and / or tension cycles, at deliberately designed hinges, e.g., when the bracing elements exceed their buckling load in compression, without affecting their ability to resist tension forces. This damage-free buckling / buckling permissibility concept applied to steel has multiple advantages over conventional moment-braced frames (MBFs) (e.g., SCBFs), namely, elimination of inelastic buckling deformation in steel members; reduction of adverse effects of low-cycle fatigue by eliminating loading cycles in compression; and repairability for both new construction and existing MBFs by means of replacement of bracing elements. For example, individual coupling elements may be replaced without replacing the entire structure or bracing system and / or seismic energy dissipation capacity may be restored after a seismic event by retightened fasteners loosened during a seismic event.

[0050] Bracing elements providing such buckling permissibility can be applied not only in MBFs but also in structural systems such as bridge braces and external dissipation devices in self-centering structures, as discussed further herein. For example, dissipative bracing elements in accordance with the present invention may be integrated with rocking columns of structures (e.g., bridges, buildings, etc.). Such rocking columns have internal reinforcements that face challenges such as inelastic buckling, fracture due to low-cycle fatigue, and complex repair processes, which can compromise their resiliency after seismic events. Accordingly, a rockingtype dissipative brace system including dissipative braces (including mechanical couplings and linkages such as a resilient rotational friction element (RRFE)) is provided to overcome inherent limitations in the conventional rocking columns. ByATTORNEY DOCKET NO. 10859.051 W01-GSB integrating controlled friction mechanisms (e.g., rotational friction) and self-centering prestressed strands, as generally known in the art, the dissipative bracing system allows for damage-free seismic energy dissipation with superior structural resilience.

[0051] In this manner, the mechanical couplings, and dissipative braces and brace systems, act somewhat like a mechanical fuse, as an intended point of energy dissipation in the event of seismic activity, thereby protecting the remainder of the brace systems and / or structures.

[0052] Accordingly, the present invention provides alternatives to conventional braces and brace systems that are designed to dissipate seismic energy in a way that emulates or substitutes for the behavior of comparable braces / brace systems, but with easily replaceable and / or reconfigurable elements so that seismic energy dissipation capacity can be quickly and readily restored after a seismic event, to provide advantages over convention bracing systems and / or approaches.

[0053] An exemplary dissipative brace system 100, also referred to as a resilient dissipative bracing system (RDBS), in the form of a concentric-braced frame (CBF) in accordance with the present invention is shown in Fig. 3. As will be appreciated from Fig. 3, the exemplary dissipative brace system 100 includes an exemplary structural frame 150. The structural frame 150 includes a plurality of interconnected frame members 150a, 150b, 150c, and may be of a type and construction similar to frames of conventional CBF / SCBF members.

[0054] Further, in accordance with the present invention, the dissipative brace system 100 includes a dissipative brace 300. The dissipative brace 300 includes a mechanical linkage 310 including at least a first coupling member 320 and a second coupling member 330 mechanically interconnected to form a mechanical coupling 200 operable to dissipate seismic energy by relative movement of the first and second coupling members 320, 330 due to friction therebetween. By way of example, the dissipative brace and the brace frame may be constructed of hollowsection high-strength steel (HSS), as is known in the art for relevant applications.

[0055] The dissipative brace 300 and / or dissipative brace system 100 may be designed to have at least the same load characteristics (carry the same predefined load) as a conventional brace member / system that it will replace, for example, to have the same or greater tensile load capacity and compression loadATTORNEY DOCKET NO. 10859.051 W01-GSB capacity (and the same energy dissipation characteristics) (i.e. , a predefined load) as the original brace / brace system.

[0056] Consistent with the present invention, the dissipative brace and / or dissipative brace system may be designed as a whole such that it will act as a buckling-controlled brace to fail in a defined manner, such that the mechanical coupling will be caused to be operated to dissipate seismic energy by relative movement of / motion between the first and second coupling members, e.g., due to friction therebetween. In this manner, the dissipative brace and / or brace system is designed to limit / localize / concentrate seismic energy dissipation to operation of the mechanical coupling to cause relative motion between the coupling members, e.g., by overcoming friction between them. In the event of seismic activity and damage, the dissipative brace / brace system and / or components thereof may be removed and replaced, or otherwise have its energy dissipation capacity restored, while any persistent portions of the brace(s) / brace system (s) / structure(s) may be retained in use, to restore structural integrity to the building / structure.

[0057] Accordingly, for example, the dissipative brace 300 / brace system 100 (e.g., Resilient Dissipative Bracing System (RDBS)) allows steel members to “deform” (e.g., buckle) at deliberately designed mechanical couplings (e.g., acting as hinges) when the brace members exceed their buckling / breakaway load in compression, without affecting their ability to resist tension forces. In this approach, friction surfaces are used to achieve desired energy dissipation levels, which may be similar to those obtained from the conventional permanent deformation / buckling of conventional hollow-steel section bracing members. Byway of example, a rotational-type mechanical coupling, in which coupling members rotate relative to one another about a shared pivot point, allows rotation after a designed level of compression force on the associated coupling members. This design approach, which permits buckling in a defined and controlled fashion, has multiple advantages over conventional MBFs: elimination of inelastic buckling deformation in steel members; reduction of adverse effects of low-cycle fatigue by eliminating loading cycles in compression; and repairability for both new construction and existing CBFs by means of replacement of bracing elements. As discussed below, this design approach, which permits buckling in a defined and controlled fashion, is applicable not only in CBFs but also in structural systems such as bridge braces and external dissipation devices in self-centering structures, as discussed further herein.ATTORNEY DOCKET NO. 10859.051 W01-GSB

[0058] Referring again to Fig. 3, the exemplary dissipative brace system 100 incorporates mechanical couplings 200, in the exemplary form of resilient rotational friction element (RRFE)-based hinges, so that, under large compressive loading, the first and second coupling members 320, 330 of each mechanical coupling 200 can rotate relative to one another (i.e. , the mechanical coupling is operating in a hinge-like motion) to accommodate the load and deformation demand, rather than developing permanent / inelastic buckling damage in a primary steel member, as would be the case in a conventional braced frame.

[0059] Further, as shown in the example of Fig. 3, the first coupling member 320 supports a first bearing plate 322 defining a first opening 324, and the second coupling member 330 supports a second bearing plate 332 defining a second opening 334.

[0060] Further, in this exemplary embodiment, the first bearing plate 322 comprises a pair of spaced flanges 321a, 321b, and the second bearing plate 332 defines at least a first respective flange 331 dimensioned to be received between the flanges 321a, 321 b of the pair of spaced flanges of the first bearing plate 322.

[0061] Further still, the first and second coupling members 320, 330 are mechanically interconnected / fastened by a mechanical fastener 340. In this example, the mechanical fastener 340 includes a bolt 342 and a nut 344. The mechanical fastener 340 acts as a pivot point for the coupling members, and is positioned to pass through the first opening 324 of the first bearing plate 322 / coupling member 320 and the second opening 334 of the second bearing plate 332 / coupling member 330 to secure the first and second coupling members 320, 330 to one another in a position in which the first bearing plate 322 abuts the second bearing plate 332. More particularly, the mechanical fastener 340 is tensioned (e.g., the nut is tightened onto the bolt by applying a desired rotation torque force) to apply a compressive force causing contact surfaces of the first and second coupling members to abut one another (more particularly, contact surfaces 326a and 326b of the first bearing plate 322 to abut contact surfaces 336a, 336b of the second bearing plate 332, in this example).

[0062] Applying an increased compressive force to the first bearing plate 322 and the second bearing plate 332 will cause increased friction between the contact surfaces 326a, 326b of the first bearing plate 322 and the contact surfaces 336a, 336b of the second bearing plate 332 during relative rotational motion of theATTORNEY DOCKET NO. 10859.051 W01-GSB first and second bearing plates about the mechanical fastener 340. Accordingly, the mechanical fastener 340 may be tensioned as desired to cause the first and second coupling members / bearing plates to resist relative rotational motion below a predefined rotational force threshold to provide a desired brace / coupling energy dissipation performance profile.

[0063] Further, in certain embodiments, one or both of abutting contact surfaces (e.g., first contact surface 326a of the first bearing plate 322 and second contact surface 336a of the second bearing plate 332 in this example) is textured to cause increased friction between the abutting contact surfaces, and therefore between the first and second bearing plates, during relative rotational motion of the first and second bearing plates about the mechanical fastener. By way of example, the contact surfaces may be textured to have an irregular granular surface detail, to have ridges, grooves, e.g., via sandblasting or deposition of metal particles through manufacturing processes such as cold spray additive manufacturing etc.

[0064] Accordingly, relative rotational motion of the first and second coupling members 320, 330, and therefore the component bearing plates 322, 332, etc., about the mechanical fastener 340, in a hinge-like motion, will dissipate via friction seismic energy applied to the mechanical coupling 200 and dissipative brace 300.

[0065] In the example of Fig.3, the dissipative brace 300 further includes first and second mounts 350, 360. Each mount 350, 360 is mechanically interconnected to one of the first and second coupling members 320, 330 to form additional mechanical couplings 200b, 200c operable to dissipate seismic energy by relative movement of the first mount and a portion of the mechanical linkage due to friction therebetween. Accordingly, the mechanically interconnected first and second coupling members 320, 330 together form a mechanical linkage 310, and the first and second mounts 350, 360 in this example also form part of the mechanical linkage 310. Each mount is adapted to be mounted to a corresponding structure, such as a frame member 150, 150, 150c of the resilient dissipative bracing system (RDBS)Zbracing system, or another structural element of a structure (e.g., a bridge column, etc.). By way of example, the mounts may be adapted for clamping, provided with holes / openings for fastening with mechanical fasteners such as nuts and bolts, etc., as will be appreciated by those skilled in the artATTORNEY DOCKET NO. 10859.051 W01-GSB

[0066] In this embodiment, each additional mechanical coupling 200b 200c is mechanically interconnected by a mechanical fastener, such as a bolt and nut, similarly to the primary mechanical coupling 220a. Accordingly, in a manner similar to that described above, the respective mechanical fasteners of these additional mechanical couplings 200b, 200c may be tensioned to apply increased compressive force to associated bearing plates and contact surfaces, which may similarly be textured to provide for increased friction, to resist relative rotational motion below a predefined rotational force threshold, and cause dissipation of seismic energy via friction during relative rotational motion about the mechanical fasteners. Accordingly, multiple couplings of a dissipative brace may be used to dissipate seismic energy via friction between coupling members (or portions thereof).

[0067] Referring now to Figs. 4A-4D, 5A and 5B, exemplary mechanical couplings / linkages in accordance with another exemplary embodiment of the present invention are shown. These mechanical linkages 310 include first and second coupling members 320, 330, mechanical fasteners 340, etc. but in these examples, the coupling members 320, 330 are constructed of flat steel (as contrasted with the hollow-section steel members in the example of Fig. 3) and have a dog bone-like shape, each including a central body 328, 338 and opposed end lobes 329a, 329b, 339a, 339b.

[0068] By way of example, Figs. 4A and 4B show the mechanical linkage 310 in a generally-linear configuration. In the generally-linear configuration the first and second coupling members 320, 330 are aligned generally-linearly. In other words, angle a formed between first coupling member 320 and second coupling member 330 may be 180 degrees (which is a linear configuration) or nearly 180 degrees, which is a generally-linear configuration, e.g. within about 1 degree or less of 180 degrees, and preferably within about 0.5 degrees or less. As used herein, a generally-linear configurations means a configuration within about 1 degree or less of a linear configuration, sufficient to promote operation of the coupling (e.g., relative rotation of the coupling members) and discourage out-of-plane buckling of the coupling members in the event that a compression load is applied to the opposite ends of the relevant coupling members. In other words, the first and second coupling members are aligned generally-linearly but are slightly misaligned to discourage jamming in a linear direction and buckling out of plane, and to promote instead relative rotational motion, in response to a compressive load. This generally-ATTORNEY DOCKET NO. 10859.051 W01-GSB linear configuration may be used to advantage in MBF / concentric braced frame-type applications, and in other instances in which exclusively or primarily compression loads are expected to be applied to the ends of the mechanical linkage during a seismic event, such that the braces / couplings will resist and carry primarily loads due to compression. In such generally-linear configurations, the brace may carry tensile loads by yielding (e.g., in the central body portions) of the coupling members 320, 330.

[0069] Figs. 4C and 4D show the mechanical linkage 310 in an angled orientation. In other words, angle a formed between first coupling member 320 and second coupling member 330 may be less than 180 degrees, as may be determined according to the needs of each application. Any suitable angle of configuration may be used, according to each individual application. In certain embodiments, an angle in the range of about 80 to about 175 degrees, such as an obtuse angle, may be used. In other words, the first and second coupling members are disposed to form an angle (e.g., an obtuse angle) to promote relative rotational motion in response to a compressive or a tensile load. This angled configuration may be used to advantage in multi-linkage structure bracing applications, and in other instances in which both compression loads and tensile loads are expected to be applied to the ends of the mechanical linkage during a seismic event, such that the coupling will resist and carry primarily loads due to both compression and tension on the mechanical linkage (e.g., due to relative rotational motion about the mechanical fastener in both clockwise and counterclockwise directions). For example, an angled orientation coupling can be mounted to a rocking system (e.g., a rocking system column) of a structure such that it will engage / undergo relative rotational motion after a certain rocking angle as a backup system (for large forces). The energy dissipation is mainly obtained from the friction at each coupling / joint, and the more torque that is used to tighten the bolt / nut / mechanical fastener, the more friction is available to dissipate seismic force.

[0070] Accordingly, each exemplary mechanical coupling serves as a rotational-friction-based element capable of engaging in rotational motion in response to deformation demands and dissipating energy, primarily through friction at its joint / hinge.

[0071] In certain embodiments, the central body 328, 338 of each of the first and second coupling members is configured to yield and deform in a regionATTORNEY DOCKET NO. 10859.051 W01-GSB other than in the regions of the opposed end lobes 329a, 329b, 339a, 339b (which house the bearing plates and contact surfaces). This allows for a measure of yielding, e.g., in tension above a predetermined threshold (e.g., after tensile forces have caused the coupling / brace to assume a linear configuration, and further cause yielding), in the region of the central body portion without permanent damage to the opposed end lobes and / or without damaging the ability of the mechanical couplings to operate to dissipate seismic energy via friction as contemplated herein. In other words, the coupling members may be designed to yield for loads above a predefined threshold, and in the event of such yielding, such coupling members may later be easily replaced (e.g., by unbolting them and replacing them with new coupling members) to restore structural integrity and load capacity to the brace / brace system and structure.

[0072] Figs. 5A and 5B illustrate an exemplary mechanical coupling 200 of another exemplary mechanical linkage (not shown) in accordance with the present invention. In this exemplary embodiment, the mechanical linkage 310 / mechanical coupling 200 includes first and second coupling members 320, 330 that are again constructed of flat steel and have a dog bone-like shape including a central body 328, 338 and opposed end lobes 329a, 329b, 339a, 339b, similar to that of Figs. 4A-4D. In this embodiment, the first bearing plate 322 comprises a pair of spaced flanges 321a, 321b, and the second bearing plate 332 defines at least a first respective flange 331 dimensioned to be received between the flanges 321a, 321b of the pair of spaced flanges of the first bearing plate 322. The first and second coupling members 320, 330 are mechanically interconnected / fastened by a mechanical fastener 340 that, in this example, includes a bolt 342 and a nut 344. The mechanical fastener 340 is positioned to pass through the first opening 324 of the first bearing plate 322 / coupling member 320 and the second opening 334 of the second bearing plate 332 / coupling member 330 to secure the first and second coupling members 320, 330 to one another in a position in which the first bearing plate 322 abuts the second bearing plate 332. More particularly, the mechanical fastener 340 is tensioned (e.g., the nut is tightened onto the bolt by applying a desired rotation torque force) to apply a compressive force causing contact surfaces of the first and second coupling members to abut one another (more particularly, contact surfaces 326a and 326b of the first bearing plate 322 to abut contact surfaces 336a, 336b of the second bearing plate 332, in this example).ATTORNEY DOCKET NO. 10859.051 W01-GSB

[0073] A theoretical analysis of the mechanical coupling / RRFE of Figs. 5A and 5B shows that the mechanical coupling / RRFE significantly enhances energy dissipation by utilizing rotational friction at the designated hinges. Here, a simplified theoretical analysis is presented.

[0074] By applying fundamental engineering mechanics principles, a theoretical equation for the initial slip moment / force or free-rotation moment can be derived. Figs. 5A and 5B illustrate the analyzed joint, where the contact surfaces are defined between an inner radius rhand an outer radius r0, according to Coulomb’s friction law Eq. (1 ), the shear stress r(r) that develops at the surface prior to slip is given by the product of the normal stress <j(r) and the coefficient of static friction / z.

[0075] x(r) = |i ■ cr(r) (1)

[0076] Consequently, the free rotation moment MRcan be calculated by integrating the differential circumferential force resulting from the shear stress distribution over the contact area, extending from the inner radius to the outer radius. The derivation follows the sequence of equations:

[0077] MR= f r ■ x(r)cM (2)

[0078] By substituting the differential area with the circumference:

[0082] Figs. 6A-6C illustrate the stress distribution induced by pretensioning the bolt. The applied pre-tension load generates a pressure (normal stress) distribution, which exhibits distinct behaviors in both the longitudinal and transverse directions. In the longitudinal direction (Fig. 6A), the normal stress follows a linear distribution along the bolt axis. However, in the transverse direction (Fig. 6B), the stress distribution is non-uniform, with the highest normal stress occurring near the inner radius and progressively decreasing toward the outer radius. Fig. 6C presents the shear stress distribution at a radial distance rc, where the conical shape of pressure intersects with the frictional interface of the interconnected plates.

[0083] A mathematical representation is provided as follows to describe the stress distribution induced by bolt pre-tensioning by employing polynomial equations of third-order and fourth-order. The normal stress <j(r) is often assumed to be uniformly distributed across the contact area, as expressed in Eq. (5). ThisATTORNEY DOCKET NO. 10859.051 W01-GSB assumption facilitates analytical modeling while maintaining reasonable accuracy in practical engineering applications.

[0084] cr(r) = oav= Pp / Ac(5)

[0085] By performing the integration in Eq. (4), substituting oavin Eq. (5), and replacing the outer radius r0by the contact radius rc, the following expression for rotational moment MRis obtained in Eq. (6).

[0087] where rhrepresents the bolt hole radius, rcdenotes the radius at which the friction surface intersects with the conical stress distribution, Acis the contact area of the interconnected plates, npis the number of interconnected friction plates, and Ppcorresponds to the pre-tensioning load applied to the bolt.

[0088] The radius rcis dependent on the conical envelope angle a as per Eq. (7). The angle a linearly decreases as the bolt size increases and increases with increases in the grip lengthHowever, it remains constant regardless of the applied pre-tensioning force.

[0090] where the dwis the washer diameter, and t is the plate thickness.

[0091] The relation between the torque and pretension force is presented through Eq. (8).

[0093] where T is the input torque, Ppis the achieved pretension load, dbis the nominal diameter of the thread, and k is a non-dimensional torque coefficient that ranges from 0.09 to 0.62, influenced by friction and the contact conditions between the plates.

[0094] Eq. (9) is used to transform between the applied axial force P and the rotational moment

[0096] where <5 is the lateral displacement at the middle of the member, and P is the applied axial compression force.

[0097] Figs. 7A and 7B shows an exemplary rocking column-type dissipative brace system 500 including a plurality of dissipative braces 300 (eachATTORNEY DOCKET NO. 10859.051 W01-GSB including mechanical couplings 200 / RRFEs) in accordance with an exemplary embodiment of the present invention.

[0098] The dissipative brace / mechanical coupling / RRFE mitigates damage in a structural member (e.g., column base) of a structure (e.g., a bridge) connections during seismic events by allowing for controlled rocking deformation within a specified range. A detailed schematic of the dissipative brace system 500 including dissipative braces 300 integrated with a reinforced concrete (RC) column and foundation is presented in Figs 7A and 7B. The rocking column could be precast RC, a concrete-filled steel tube, or steel columns with internal unbonded prestressed tendons, as known in the art. At the base of the column, a hollow steel section capped with an end plate protects the column edges from damage during rocking. A pre-embedded steel plate in the foundation forms a contact surface, preventing localized concrete crushing and other potential damage during the rocking motion. Post-tensioned unbonded prestressed tendons provide efficient self-centering forces, ensuring the system returns to its initial position after seismic events. These tendons are designed to remain elastic during severe earthquakes. More particularly, Figs. 7A and 7B show schematic detail of mechanical couplings / RRFE’s integrated into rocking columns and an RC foundation for a generally-linear configuration and an angled configuration, respectively.

[0099] Each exemplary dissipative brace 300 incorporates three mechanical couplings 200 designed to operate as hinges that dissipate seismic energy through rotational friction under compression forces and tension forces, if assembled in an angled configuration, facilitated by rotational surfaces, pretensioned bolts, specialized washers, and mechanisms enhancing post-buckling residual strength. In a generally-linear configuration, each dissipative brace 300 responds through each coupling member yielding in tension (e.g., in a central region) and rotational friction in compression, as will be appreciated from Figs. 8A-8C. In an angled configuration (Figs. 9A-9C), each dissipative brace 300 and associated mechanical coupling / RRFE dissipates seismic energy in both tension and compression modes through the rotational friction between coupling members, up to a specified rocking angle; after that, tensile yielding of coupling members will occur, preventing risking undesired rotational angles during the rocking motion at higher earthquake excitations.ATTORNEY DOCKET NO. 10859.051 W01-GSB

[0100] Accordingly, each dissipative brace 300 serves as a repairable / replaceable seismic energy dissipator, allowing for easy replacement after severe seismic events by simply unbolting and replacing the damaged components.

[0101] Figs. 7A-8B illustrate the dissipative braces 300 and dissipative bracing (rocking) system 500 in generally-linear and angled configurations. During rocking motion of the structure during a seismic event, the stress distribution at the column base evolves as the horizontal load increases. Initially, the contact stress is evenly distributed across the base. Under lateral forces, compressive stress on the tension side diminishes and eventually reduces to zero (overcoming decompression), while the compression side’s stress increases. As loading continues, stress concentration shifts entirely to the compression side. When the contact surface reaches its ultimate state, the column exhibits rocking behavior while maintaining anti-overturning capacity. However, if deformation exceeds the critical state where the gravitational action and strands’ force line passes through the support point, the system risks overturning and structural failure.

[0102] Elastic restoring forces may be provided by prestressed tendons and the column's supporting weight to ensure the system reverts to its central position after deformation, in the nature of a self-centering mechanism. This self-centering capability is critical for achieving the resilient functionality of the system. Higher prestressing forces, achieved through increased prestressing levels or larger tendon cross-sectional areas, enhance self-centering performance. However, a balance must be maintained between energy dissipation and self-centering capacity, as excessive energy dissipation may hinder self-centering efficiency. A careful selection of design parameters is essential to optimize both attributes, thereby improving the overall resilience of the mechanical coupling / RRFE system.

[0103] In conventional RC (reinforced concrete) column systems, seismic energy dissipation occurs primarily through mechanisms such as concrete cracking, concrete spalling, slippage between steel reinforcement and concrete, and reinforcing bar buckling and fracture, which provide limited energy dissipation capacity. The dissipative braces and bracing systems of the present invention provide for improved energy dissipation by concentrating deformation at designated couplings, which function as hinges to dissipate energy via friction. Figs. 10A and 10B show the theoretical hysteresis of mechanical coupling / RRFE within rocking columns in generally-linear and angled configurations, respectively. As shown inATTORNEY DOCKET NO. 10859.051 W01-GSB Fig. 10A, for the generally-linear configuration, energy dissipation is achieved through rotational friction on the compressed side and member yielding on the tensioned side. In contrast, for the angled configuration, energy dissipation is achieved through rotational friction on both sides up to a specified rocking angle, as shown in Fig. 10B. Beyond this angle, the straight brace dissipates energy primarily through yielding while at the same time controlling the column's inclination.

[0104] Preferably, braces 300 may be provided on opposite sides of a column or other structures element (e.g., separated by 180 degrees about an axis of a column, for example), e.g., as shown in Figs. 7A-9C. This allows pairs of opposed dissipative braces to work in concert.

[0105] The dissipative brace system 500 dissipates seismic energy within the dissipative braces 300, minimizing the impact on the primary structural elements. This design helps to ensure that damage is controlled and localized and does not compromise the integrity of the main structure. After an earthquake, damaged braces or components thereof can be quickly replaced, restoring the system's resilience with minimal downtime.

[0106] The rocking-type dissipative brace system with RRFE mechanical couplings / dissipative braces can be used in existing and new structural systems (reinforced concrete structures, wood structures, and steel structures) and has multiple benefits over conventional ones: (1) elimination of damage associated with inelastic buckling deformation; (2) reduced adverse effects from low-cycle fatigue by eliminating strain cycles in compression; (3) repairability for both new and existing rocking structures through re-setting or replacement of devices; and (4) feasibility and affordability by simplifying constructability and providing adequate tolerance compared to commonly used energy dissipative devices.

[0107] Further exemplary placements of the dissipative brace / mechanical couplings in structural systems are presented in Figs. 11A--17. For example, Fig. 11 A shows a single column with angled configuration braces at top and bottom connections. Fig. 11 B shows a double column with angled configuration braces at top and bottom connections. Fig. 11C shows a single column with a generally-linear configuration brace at top and bottom connections. Fig. 11 D shows a double column with generally-linear braces at top and bottom connections.

[0108] In a steel bent (e.g., steel or concrete-filled steel tube) application, Figs. 13A and 13B show that an angled configuration dissipative brace can beATTORNEY DOCKET NO. 10859.051 W01-GSB engaged with a fixed wall / column after a certain rotation angle of the plastic hinge as a backup system (for large forces), and the other side can deform more, and reiterates that the dissipative energy mainly comes from the friction from each joint and the more torque to tie the bolt, the more friction / energy to dissipate the force. An angled configuration dissipative brace can be engaged within the top or bottom of the wall / column after a certain rotation angle of the plastic hinge as a backup system (for large forces), and the other side will deform more, with the same emphasis on friction at joints and increased dissipation with higher bolt torque (Figs 12A and 12B.

[0109] For bridge applications, Figs. 12A and 12B show engagement of the angled dissipative brace as a backup system after a certain rotation angle (with energy dissipation primarily from friction at each joint and increased dissipation with increased bolt torque), and includes both a single-column and a multi-column type placement arrangement (Fig. 12A and 12B). In another bridge-related placement, the angled dissipative brace can be engaged after a certain elongation of the bridge girder, and the other side can deform more, with dissipative energy mainly coming from the friction from each joint, and again that the more torque to tighten the bolt, the more friction / energy to dissipate the force, as shown in Fig. 14 Fig. 15 depicts a building-grid schematic and repeated text describing engagement of the angled configuration dissipative brace with a fixed wall / column after a certain rotation angle of the plastic hinge as a backup system, with the same friction / torque relationship; the bottom of the page shows repeated placements consistent with a “steel moment resisting connection” use case.

[0110] A dissipative brace system example in the nature of a moment resisting frame (MRF) is shown in Fig. 16. In this depiction, an angled configuration brace is shown at connection regions, and a “PH zone” is indicated (consistent with a plastic hinge zone labeling in the figure). The angled configuration dissipative brace will be engaged with the MRF after a certain rotation angle of the plastic hinge as a backup system (for large forces), and the other side will deform more, and again that the dissipative energy mainly comes from the friction from each joint and that increased bolt torque increases friction / energy dissipation. Fig 17 shows exemplary configurations of the dissipative braces in V-brace, inverted-V, diagonal (left), eccentric braced frame (middle), and horizontal members in SCBR (right)applications.ATTORNEY DOCKET NO. 10859.051 W01-GSB

[0111] The performance of an exemplary brace within an exemplary rocking-type brace system under monotonic and cyclic axial loading conditions was tested. A scaled rocking column component test featured a circular cross-sectional dimension of 10 in. in diameter and a height of 40 in. To protect the base of the column during rocking and provide a connection point for the dissipative brace, the column was equipped with a steel hollow section at its base, measuring 3 / 16-inch in thickness, which also facilitates the welding of the widening bracket connecting the coupling’s / RRFE’s gusset plate to the column through two bolts. The foundation is a reinforced concrete block with sectional dimensions of 50 x 50 in. and a height of 12 in. Embedded within the foundation are %-inch diameter connecting bolts or anchors with an embedded length of 9 in., designed to secure the mounting plate. Additionally, the precast concrete column can be equipped with four longitudinal PVC tubes to accommodate post-tensioned unbonded prestressed tendons, ensuring optimal structural performance. The overall rocking system geometry proportionally scales the dissipative brace specimen within a practical and representative rocking system, ensuring accurate performance evaluation and structural applicability.

[0112] The exemplary dissipative brace includes three mechanical couplings functioning as hinges: two located at the ends and one positioned at the center, as shown in a sequence of schematic deformation shapes in Figs. 18 and 19. Each coupling member’s shape / configuration can be optimized to localize yielding at the midsection by introducing a reduced cross-section, while the enlarged extremities ensure structural integrity against all potential joint failure modes, resulting in a dog-bone configuration. For large-scale applications, the specimen dimensions, material strength, and number of layers / plates can be decided based on structural demands. Each mechanical coupling / hinge can incorporate at least two friction surfaces, as well as mechanical fasteners including shoulder bolts, washers, and nuts. To optimize functionality, the end couplings / hinges can be snugly tightened to minimize friction and facilitate rotation, while the central hinge can be tightened with exemplary torques of 0 (snug tightened), 20, 30, and 40 lb. ft to evaluate its influence on performance. The specimens can be fabricated from A36 steel, and the structural steel plates can be machined using water jetting and sandblasted before welding. An exemplary specimen comprised three dog-bone elements: one with an exemplary thickness of 0.25 in. and two with exemplary thicknesses of 0.125 in.,ATTORNEY DOCKET NO. 10859.051 W01-GSB each having a narrow width of 1.5 in. The bolt diameter can be % inch, classified as Group 120 as per AISC 360-22. This configuration provides a nominal tensile capacity of up to 13.5 kips, while the nominal compression capacity, accounting for out-of-plane buckling in the absence of the middle hinge, is 3.1 kips, according to AISC 360-22.

[0113] Exemplary structural components of the rocking column are presented in Figs. 18-21. As will be appreciated from Figs. 20 and 21 , each dissipative brace 300 may be connected to the column C through horizontal widening brackets 370 (welded to a hollow steel section 380). Each widening bracket 370 defines slotted openings 372 to decouple the rocking columns from the dissipative braces 300 when the column rocks in any direction rather than the axial direction of the dissipative braces. The mount 350 may be configured with mounting flanges 352 defining openings 354 for carrying bolts passed through the slotted openings 372 of the widening brackets 370 to form a mechanical interconnection that allows for translation of the bolts within the slots to provide such decoupling / loose coupling. The dissipative brace 300 may further be connected to the foundation through an opposing mount 360 and concrete anchor fasteners, as best shown in Figs. 18-21. Additionally, all connections, including the one in the enlarged section of the dog-bone and the connection to the column / footing, are designed as capacity-protected elements. This ensures that these components remain elastic during seismic excitation, effectively confining failure to the replaceable element.

[0114] Figs. 22A-22D illustrates the theoretical force-displacement response of an exemplary dissipative brace 300, considering variations in the applied bolt torque and the non-dimensional torque coefficient (fc). The analysis encompasses exemplary torque levels of 20, 30, and 40 Ib.ft, with k values ranging from 0.09 to 0.62, an exemplary friction factor ( / z) of 0.3, and an exemplary conical envelope angle (a) of 30°. The region between the two boundary curves represents the full spectrum of possible force-displacement behaviors due to variations in k. Specifically, Fig. 22A depicts the specimen configuration, while Figs. 22B, 22C and 22D present the corresponding theoretical force-displacement curves for bolt torques of 20, 30, and 40 Ib.ft, respectively.

[0115] As part of an experimental test, a loading test was conducted using a 100-kN capacity actuator to apply controlled loads to exemplary dissipative braceATTORNEY DOCKET NO. 10859.051 W01-GSB specimens, allowing for a precise evaluation of their structural performance under specified conditions and configurations. Two categories were tested: monotonic loading and cyclic loading. The monotonic loading tests can determine the compression capacity of the dissipative brace specimens, while the cyclic loading tests focus on examining the post-buckling behavior and the energy absorption capacity of the dissipative brace. An experimental setup is illustrated in Fig. 23, and the cyclic loading schemes are shown in Fig. 24. The cyclic loading schemes may consist of Cyclic Loading-1 , with an exemplary six cycles ranging from 0 to -0.5 in.; Cyclic Loading-2, with an exemplary six cycles ranging from 0 to -1.0 in.; Cyclic Loading-3, with an exemplary six cycles ranging from 0 to -1.5 in.; and Cyclic Loading-4, with an exemplary eight cycles including both positive and negative amplitudes, where the maximum tension amplitude was 0.5 in., and the maximum compression amplitude was -0.5 in. All loading protocols were applied at a constant frequency of 0.5 Hz, and tests can be designed to terminate immediately upon reaching the out-of-plane buckling capacity of one segment.

[0116] During the loading program, static load was first performed with different fastener torque at the central coupling / hinge and hand tightening of the distal couplings / hinges. From this procedure, a torque level was selected for a dynamic loading protocol. The static load (pushover compression) protocol was performed with different torque levels (0, 20, 30, and 40 ft- lb) at the middle coupling / hinge. The dynamic load protocol was performed considering hand-tightened distal couplings / hinges and a 30 ft- lb tightened bolt at the central coupling / hinge; there were four dynamic load tests as presented in Fig. 25, which plots the different dynamic displacement-time histones (Dynamic-test-1 through Dynamic-test-4).

[0117] The test case design and corresponding loading conditions are summarized in Table 2, detailing an exemplary 17 test cases designed to evaluate the dissipative brace performance under varying influencing factors, including applied torque levels and loading conditions. Specimens were subjected to monotonic compression loading, while remaining specimens underwent cyclic loading. Among these, two exemplary specimens are of particular interest: the first specimen (Spc.1) features a hole diameter exceeding the bolt diameter by 1 / 8 in., while the second specimen (Spc.2) has a hole diameter larger by 1 / 16 in. The labeling format for the specimens in each test case is explained in Fig. 26.ATTORNEY DOCKET NO. 10859.051 WO1-GSB

[0118] Testing was conducted with two specimens: the first (Spc.1 ) had a hole diameter larger than the bolt diameter by 1 / 8 in, and the second (Spc.2) by 1 / 16 in. The test setup is shown in Fig. 23. which includes figure-incorporated labels identifying a Supporting Column, the Specimen, a Horizontal Actuator, Clamps, and a Supporting beam (Fig. 23).

[0119] Table 2. Specimens’ notation and description.

[0120] For the monotonic loading condition, experimental observations for the first four specimens in Table 2 demonstrate typical and consistent characteristics regarding their structural performance. However, variations in peak values and post-ATTORNEY DOCKET NO. 10859.051 W01-GSB buckling behavior were observed, attributed to the different clamping forces applied to the middle hinge through torque. Fig. 25 illustrates the force-displacement curves for Spc.1 under monotonic compression loading with varying torque levels (0, 20, 30, and 40 lb. ft). The fluctuations in the plotted graph are attributed to the static nature of the test and the steady loading rate.

[0121] A torque level of 30 lb. ft was selected for cyclic tests. Although this torque level has 60% of the energy obtained from torque 40 Ib.ft, it provides stable and predictable behavior under cyclic loading. Fig. 27 presents the friction energy of Spc.1 under different torque levels, highlighting the relationship between applied torque and friction energy.

[0122] A mechanistic model was developed based on experimental results obtained from monotonic static loading. Fig. 28A illustrates a model for tested dissipative brace specimens, which is adapted to describe the rotational friction behavior as a function of axial force (P) and axial displacement (4). The corresponding deformed shapes of the dissipative brace specimens at key labeled points within the mechanistic model are shown in Fig. 28B. Furthermore, the key parameters influencing the mechanistic model are summarized in Table 3, highlighting their significance in determining the model's predictive capability.

[0123] Table 3. Mechanistic model parameters for the tested specimens in Figs. 28A-28B.

[0124] Figs. 29A-29D present a comparison between the theoretical (obtained from (1), (2), (3), (4), (5), (6), (7), (8), (9)) and experimental results, considering a friction factor ( / z) of 0.3, and a conical envelope angle (a) of 30°. The theoretical results are adjusted by incorporating the slippage distance specified in Table 3 for each specimen. Fig. 29A illustrates the force-displacement response ofATTORNEY DOCKET NO. 10859.051 W01-GSB the first specimen (Spc.1-S-0-0), where a torque of approximately 2 lb. ft is assumed in the theoretical model to introduce a pretension load on the bolts representing a snug-tightened bolt, thereby generating a rotational moment (MR).

[0125] Figs. 29B, 29C, and 29D depict the results for the remaining dissipative brace specimens (for cyclic loading with snug-tightened bolts for (a) Cyclic Load-1 , (b) Cyclic Load-2, and (c) Cyclic Load-3), which are subjected to exemplary bolt torques of 20, 30, and 40 lb. ft, respectively. These specimens exhibit different rotational moments at the middle hinges compared to the end hinges. The rotational moment at the end hinges (MR-E) corresponds to a torque of 2.0 lb. ft, whereas the middle rotational moment (MR-M) is derived from the torque values provided in Table 2. All experimental data points lie within the bounds defined by the upper and lower theoretical curves where k ranges from 0.09 to 0.62, demonstrating consistency between the experimental and theoretical models.

[0126] The experimental observations for cyclic loading conditions of the exemplary dissipative brace specimens, as outlined in Table 2, subjected to cyclic loading, which was previously shown in Fig. 24, demonstrate consistent resilient performance across all tests, with variations in peak values and post-buckling behavior attributed to differences in pretension forces. The results from forcedisplacement curves (Figs. 32A-32C) provide insights into the structural response of the dissipative brace specimens under varying cyclic loading conditions, hole size, configurations, and torque levels.

[0127] Figs. 30A-30C and Fig. 31A-31C compare Spc.1 and Spc.2 under cyclic loading schemes 1 , 2, and 3 with both specimens tested in a straight configuration and using a snug hand-tightened bolt and a torque level of 30 Ib.ft, respectively. Energy dissipation occurs on both the tension and compression sides, even though the applied loading cycles were in compression only. In hand-tightened dissipative brace specimens, no significant resistance was observed, whereas 30 Ib.ft torque-tightened dissipative brace specimens exhibited substantial resistance, with variations in peak tension and compression responses. Spc.1, having a larger hole diameter (1 / 8 in. larger than the bolt diameter), consistently exhibited greater horizontal slippage compared to Spc.2 (1 / 16-inch clearance); this is clear in Figs 31A-31C, however, in Fig. 32 the specimens’ bolts lack sufficient torque to generate pre-tension, leading to rotational friction resistance that closely matchesATTORNEY DOCKET NO. 10859.051 W01-GSB sliding friction resistance. The force-displacement curves further reveal differences in breakaway forces and dissipated energy. For instance, in Cyclic Loading-1, Spc.1 rotated at approximately -1.0 kips without notable changes in the sequential cycles. Spc.2 rotated at -1.2 kips during the initial cycle and degraded to -0.55 kips in subsequent cycles. In Cyclic Loading-2 and Cyclic Loading-3, Spc.2 demonstrated higher breakaway forces (-2.6 kips and -2.4 kips, respectively) and larger hysteresis compared to Spc.1 , indicating better energy dissipation capacity.

[0128] Fig. 33 shows energy dissipation for cyclic loadings with different torque levels. The dissipative brace is an energy-dissipating device designed to enhance the seismic resilience of rocking column systems by reducing damage in column base connections through controlled rocking deformation and energy dissipation at specific hinges. Features include rotational friction-based energy dissipation, replaceable components for quick restoration, and self-centering mechanisms driven by unbonded prestressed tendons, which minimize damage to primary structural components and improve repairability compared to traditional systems.

[0129] Figs. 34A-34C are partial, exploded, and assembled perspective views, respectively, of an exemplary mechanical coupling 200 including a supplementary dissipative mechanism in accordance with an alternative embodiment of the present invention. In this embodiment, at least one of the first and second coupling members (particularly, in this example, each of spaced flanges 321 , 321 b), defines at least one additional opening 329, and another of the first and second coupling members (particularly, in this example, flange 331) defines at least one arcuate slot 339 positioned to align with the at least one additional opening, and the first and second coupling members are joined by at least one mechanical fastener 340 via the first and second openings 324, 334. In this example, the dissipative brace further comprises a deformable element 355 disposed within each arcuate slot 339, and at least one pin 345 (e.g., a pin or bolt), each extending through the first and second coupling members / flanges via the at least one additional opening 329 and a respective arcuate slot 339. In this manner, relative rotational motion of the first and second coupling members 320, 330 cause each pin 345 to traverse each respective arcuate slot 339 and correspondingly deform the deformable element 355 disposed therein. In this manner, additional seismic energy is dissipated by deformation of the deformable element, such that this arrangement provides aATTORNEY DOCKET NO. 10859.051 W01-GSB supplementary dissipative mechanism that dissipates additional seismic energy, in addition to the seismic energy dissipated due to friction between the bearing plates / contact surfaces of the coupling members

[0130] Accordingly, the dissipative brace and associate mechanical couplings represent an advancement in seismic-resistant design, offering enhanced energy dissipation, repairability, and self-centering functionality. The rocking-type dissipative brace system concentrates seismic energy dissipation within dissipative brace, a replaceable component, preserving the integrity of the main structure. The dissipative brace’s superior performance has been validated under both monotonic and cyclic loads, showcasing its energy dissipation and post-buckling capabilities without exhibiting damages. With different levels of torque, the friction energy increased from 0.10 to 1.11 kips. in reflecting 11 times more when going from snug-tightened to torque level 40 Ib.ft. A mechanistic model based on monotonic loading experiments was developed to guide friction energy design, with key parameters identified to enhance predictive accuracy. The theoretical equations successfully captured the behavior of the dissipative brace, providing a reliable tool for predicting performance and optimizing design parameters. The devices are activated in rotational friction instead of jamming at the middle hinge, so that no buckling occurs in the straight segment.

[0131] An exemplary critical commercial problem is damage of steel members under compression loading cycles in seismic prone zones. Current practice for seismic protective systems includes the use of expensive devices such as viscous dampers, wall dampers, seismic isolation, and other rocking systems. In an exemplary implementation, the dissipative braces are relatively inexpensive and easy for local steel fabricators to manufacture, providing very cost-efficient and repairable options to existing counterparts. Additional advantages include one or more of the following: no additional cost to steel members resisting seismic forces; damage free steel members; limiting damages in fuses which are replaceable and repairable; ability to extend the manufacture to additive manufacture of the fuses; and suitability for new construction and upgrading substandard buildings in seismic zones.

[0132] Possible exemplary uses of the dissipative braces include in steel braced frames (concentric, eccentric, X braces, V braces, etc.); steel braces inATTORNEY DOCKET NO. 10859.051 W01-GSB bridges; introducing steel substructure systems for bridges; and external components for other systems such as rocking and self-centering systems.The present invention also provides a method for providing a seismic-energy resistant structure. More particularly, the method comprises mechanically coupling a mechanical linkage configured to carry a desired load without plastic deformation to the structure, the mechanical linkage comprising at least a first coupling member and a second coupling member mechanically interconnected to form a mechanical coupling operable to dissipate seismic energy by relative movement of the first and second coupling members due to friction therebetween. Such mechanical coupling of the mechanical linkage to the structure may involve securing ends of the mechanical couplings to members of a frame, securing a first end of the mechanical couplings to a first member of a frame comprising a plurality of frame members; and securing a second end of the mechanical couplings to a second member of the frame. Further, such mechanical coupling may involve tensioning a mechanical fastener that to apply a compressive force causing surfaces of the first and second coupling members to abut one another, e.g., by applying a rotational torque force to a nut on a bolt. This may involve securing ends of the mechanical couplings to at least one structural element configured to exhibit rocking motion during a seismic event, and may involve securing ends of the mechanical couplings to the at least one structural element at a first location, and further mechanically coupling a second mechanical linkage to the at least one structural element at a second location opposite the first location, to provide a rocking-type dissipative brace system.

[0133] After a seismic event, any damaged elements may be replaced while other elements are retained, and in some cases, seismic dissipation capacity may be restored simply by re-tensioning / re-torquing the mechanical fasteners / bolts of the mechanical couplings of the dissipative braces, without a need for replacement of any elements.

[0134] While there have been described herein the principles of the invention, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation to the scope of the invention. Accordingly, it is intended by the appended claims, to cover all modifications of the invention which fall within the true spirit and scope of the invention.

Claims

ATTORNEY DOCKET NO. 10859.051 W01-GSB What is claimed is:

1. A dissipative brace operable to dissipate seismic energy, the dissipative brace being configured to carry a predefined load applied to a structure, the dissipative brace comprising:a mechanical linkage comprising at least a first coupling member and a second coupling member mechanically interconnected to form a mechanical coupling operable to dissipate seismic energy by relative motion of the first and second coupling members due to friction therebetween.

2. The dissipative brace of claim 1 , wherein the first and second coupling members are mechanically interconnected by a mechanical fastener.

3. The dissipative brace of claim 2, wherein the first and second coupling members are mechanically interconnected by a mechanical fastener that is tensioned to apply a compressive force causing surfaces of the first and second coupling members to abut one another.

4. The dissipative brace of claim 3, wherein the mechanical fastener comprises a bolt and a nut, and wherein the mechanical fastener is tensioned to apply the compressive force by applying a rotational torque force to the nut on the bolt.

5. The dissipative brace of claim 1 , wherein the first coupling member supports a first bearing plate defining a first opening, and the second coupling member supports a second bearing plate defining a second opening; and wherein the first and second coupling members are mechanically fastened by a mechanical fastener passing through the first opening of the first coupling member and the second opening of the second coupling member to secure the first and second coupling members to one another in a position in which the first bearing plate abuts the second bearing plate, the mechanical fastener being tensioned to apply a compressive force to the first bearing plate and the second bearing plate to cause increased friction between said first bearing plate and said second bearing plate during relative rotational motion of the first and second bearing plates about theATTORNEY DOCKET NO. 10859.051 W01-GSB mechanical fastener to dissipate via friction any seismic energy applied to the mechanical coupling to cause relative rotational motion of the first and second bearing plates.

6. The dissipative brace of claim 5, wherein the first bearing plate comprises a pair of spaced flanges, and there the second bearing plate defines at least a first respective flange dimensioned to be received between flanges of the pair of spaced flanges of the first bearing plate.

7. The dissipative brace of claim 5, wherein the first bearing plate defines a first contact surface and the second bearing plate defines a second contact surface positioned to abut the first contact surface, and wherein at least one of the first contact surface and the second contact surface is textured to cause increased friction between the first and second contact surfaces, and therefore between the first and second bearing plates, during relative rotational motion of the first and second bearing plates about the mechanical fastener.

8. The dissipative brace of claim 5, wherein the mechanical fastener is tensioned to apply a compressive force to the first bearing plate and the second bearing plate to cause increased friction between the first bearing plate and the second bearing plate during relative rotational motion of the first and second bearing plates about the mechanical fastener.

9. The dissipative brace of claim 5, wherein the mechanical fastener comprises a bolt and nut, and wherein the mechanical fastener is tensioned to apply the compressive force by applying a rotational torque force to the nut on the bolt.

10. The dissipative brace of claim 1 , wherein at least one of the first and second coupling members defines at least one additional opening, and wherein another of the first and second coupling members defines at least one arcuate slot positioned to align with the at least one additional opening, and the first and second coupling members are joined by a mechanical fastener via the first and second openings, wherein the dissipative brace further comprises a deformable element disposed within each arcuate slot, and at least one pin, each pin extending throughATTORNEY DOCKET NO. 10859.051 W01-GSB the first and second members via the at least one additional opening and a respective arcuate slot, whereby relative rotational motion of the first and second coupling members cause each pin to traverse each respective arcuate slot and correspondingly deform the deformable element disposed therein, whereby additional seismic energy is dissipated by deformation of the deformable element.

11. The dissipative brace of claim 1 , further comprising:a first mount configured to be mounted to the structure, the first mount being mechanically interconnected to a first end of the mechanical linkage to form another mechanical coupling operable to dissipate seismic energy by relative movement of the first mount and a portion of the mechanical linkage due to friction therebetween; anda second mount configured to be mounted to the structure, the second mount being mechanically interconnected to a second end of the mechanical linkage to form yet another mechanical coupling operable to dissipate seismic energy by relative motion of the second mount and another portion of the mechanical linkage due to friction therebetween.

12. A mechanical coupling operable to dissipate seismic energy, the mechanical coupling comprising:a first coupling member supporting a first bearing plate defining a first opening;a second coupling member supporting a second bearing plate defining a second opening; anda mechanical fastener passing through the first opening of the first coupling member and the second opening of the second coupling member to secure the first and second coupling members to one another in a position in which the first bearing plate abuts the second bearing plate, the mechanical fastener being tensioned to apply a compressive force to the first bearing plate and the second bearing plate to cause increased friction between said first bearing plate and said second bearing plate during relative rotational motion of the first and second bearing plates about the mechanical fastener to dissipate via friction any seismic energy applied to the mechanical coupling to cause relative rotational motion of the first and second bearing plates.ATTORNEY DOCKET NO. 10859.051 W01-GSB13. The mechanical coupling of claim 12, wherein the first bearing plate comprises a pair of spaced flanges, and there the second bearing plate defines at least a first respective flange dimensioned to be received between flanges of the pair of spaced flanges of the first bearing plate.

14. The mechanical coupling of claim 12, wherein the first bearing plate defines a first contact surface and the second bearing plate defines a second contact surface positioned to abut the first contact surface, and wherein at least one of the first contact surface and the second contact surface is textured to cause increased friction between the first and second contact surfaces, and therefore between the first and second bearing plates, during relative rotational motion of the first and second bearing plates about the mechanical fastener.

15. The mechanical coupling of claim 12, wherein the mechanical fastener is tensioned to apply a compressive force to the first bearing plate and the second bearing plate to cause increased friction between the first bearing plate and the second bearing plate during relative rotational motion of the first and second bearing plates about the mechanical fastener.

16. The mechanical coupling of claim 12, wherein the mechanical fastener comprises a bolt and nut, and wherein the mechanical fastener is tensioned to apply the compressive force by applying a rotational torque force to the nut on the bolt.

17. The mechanical coupling of claim 12, wherein the mechanical fastener comprises a bolt and nut, and wherein the mechanical fastener is tensioned to cause the first and second bearing plates to resist relative rotation motion below a predefined rotational force threshold.

18. The mechanical coupling of claim 12, wherein at least one of the first and second coupling members defines at least one additional opening, and wherein another of the first and second coupling members defines at least one arcuate slot positioned to align with the at least on additional opening then the first and second coupling members are joined by a mechanical fastener via the first and secondATTORNEY DOCKET NO. 10859.051 W01-GSB openings, the mechanical coupling further comprises a deformable element disposed within each arcuate slot, and at least one pin, each extending through the first and second members via the at least one additional opening and a respective arcuate slot, whereby relative rotational motion of the first and second coupling members cause each pin to traverse each respective arcuate slot and correspondingly deform the deformable element disposed therein, whereby additional seismic energy is dissipated by deformation of the deformable element.

19. A dissipative brace operable to dissipate seismic energy, the dissipative brace being configured to carry a predefined load applied to a structure, the dissipative brace comprising:a first mounting plate configured for mounting to the structure, the first mounting plate supporting a first bearing plate defining a first opening;a first coupling member having a pair of opposed ends, first end of the first coupling member supporting a second bearing plate defining a second opening, a second end of the first coupling member supporting a third bearing plate defining a third opening;a second coupling member having a respective pair of opposed ends, a respective first end of the second coupling member supporting a fourth bearing plate defining a fourth opening, a respective second end of the second coupling member supporting a fifth bearing plate defining a fifth opening;a second mounting plate configured for mounting to the structure, the second mounting plate supporting a sixth bearing plate defining a sixth opening; anda plurality of mechanical fasteners securing selected ones of the coupling members and mounting plates to one another in positions in which respective bearing plates abut one another, a first mechanical fastener of the plurality of mechanical fasteners passing through the first opening of the first mounting plate and the second opening of the first coupling member, a second mechanical fastener of the plurality of mechanical fasteners passing through the third opening of the first coupling member and the fourth opening of the second coupling member, a third mechanical fastener of the plurality of mechanical fasteners passing through the fifth opening of the second coupling member and the sixth opening of the second mounting plate,ATTORNEY DOCKET NO. 10859.051 W01-GSB each of the plurality of mechanical fasteners being tensioned to apply a compressive force to respective bearing plates to cause increased friction between the respective bearing plates during relative rotational motion thereof to dissipate via friction any seismic energy applied to the mechanical coupling to cause relative rotational motion between abutting bearing plates.

20. The dissipative brace of claim 19, wherein the mechanical fasteners are fastened to secure the first and second coupling members in a linear orientation in which the first and second coupling members are aligned generally-linearly but slightly misaligned to promote relative rotational motion in response to a compressive load.

21. The dissipative brace of claim 19, wherein each of the first and second coupling members are configured to yield and deform in a region other than the first and second bearing plates in response to a tensile load above a predetermined threshold.

22. The dissipative brace of claim 19, wherein the mechanical fasteners are fastened to secure the first and second coupling members in an angled orientation in which the first and second coupling members are disposed to form an obtuse angle therebetween to promote relative rotational motion in response to both a compressive load and a tensile load.

23. A dissipative brace operable to dissipate seismic energy, the dissipative brace being configured to carry a predefined load applied to a structure, the dissipative brace comprising:a mechanical linkage comprising at least a first coupling member and a second coupling member mechanically interconnected to form a mechanical coupling operable to dissipate seismic energy by relative movement of the first and second coupling members due to friction therebetween;a first mounting plate configured for mounting a first end of the mechanical linkage to the structure; anda second mounting plate configured for mounting a second end of the mechanical linkage to the structure.ATTORNEY DOCKET NO. 10859.051 W01-GSB 24. The dissipative brace of claim 23, wherein first and second coupling members are mechanically interconnected by a mechanical fastener.

25. The dissipative brace of claim 23, wherein each pair of adjacent coupling members of the mechanical linkage are mechanically interconnected by a mechanical fastener.

26. The dissipative brace of claim 23, wherein each of the first mounting plate and the second mounting plate are interconnected to the mechanical linkage by a respective mechanical fastener.

27. The dissipative brace of claim 23, wherein the first and second coupling members are mechanically interconnected by a mechanical fastener that is tensioned to apply a compressive force causing surfaces of the first and second coupling members to abut one another.

28. The dissipative brace of claim 27, wherein the mechanical fastener comprises a bolt and a nut, and wherein the mechanical fastener is tensioned to apply the compressive force by applying a rotational torque force to the nut on the bolt.

29. The dissipative brace of claim 23, wherein mechanical fasteners are fastened to secure the first and second coupling members in a linear orientation in which the first and second coupling members are aligned generally-linearly but slightly misaligned to promote relative rotational motion in response to a compressive load.

30. The dissipative brace of claim 23, wherein mechanical fasteners are fastened to secure the first and second coupling members in an angled orientation in which the first and second coupling members are disposed to form an obtuse angle therebetween to promote relative rotational in response to both a compressive load and a tensile load.ATTORNEY DOCKET NO. 10859.051 W01-GSB 31. A dissipative brace system operable to dissipate seismic energy, the dissipative brace being configured to carry a predefined load, the dissipative brace comprising:a structural member of a structure; anda dissipative brace comprising:a mechanical linkage comprising at least a first coupling member and a second coupling member mechanically interconnected to form a mechanical coupling operable to dissipate seismic energy by relative movement of the first and second coupling members due to friction therebetween;a first mounting plate configured for mounting a first end of the mechanical linkage to the structure; anda second mounting plate configured for mounting a second end of the mechanical linkage to the structure.

32. The dissipative brace system of claim 31 , wherein the structural member comprises a frame comprising a plurality of frame members, and wherein each of the first and second mounting plates is mounted to a selected one of the plurality of frame members.

33. The dissipative brace system of claim 31 , further comprising a mount secured to the structural member at a first position, wherein at least one of the first mounting plate and the second mounting plate is adapted for mounting to the mount.

34. The dissipative brace system of claim 33, further comprising a second mount secured to the structural member at a second position opposite the first position, wherein one of the first mounting plate and the second mounting plate is adapted for mounting to the mount and another of the first mounting plate and the second mounting plate is adapted for mounting to the second mount.

35. The dissipative brace system of claim 31 , wherein the mount and the at least one of the first mounting plate and the second mounting plate are adapted for mounting to the mount to permit relative translational motion between the mounting and the respective mounting plate.ATTORNEY DOCKET NO. 10859.051 W01-GSB 36. A structure comprising a dissipative brace system operable to dissipate seismic energy during a seismic event, the structure comprising:at least one structural element configured to exhibit rocking motion during a seismic event;a dissipative brace system joined to each structural element, each dissipative brace system comprising:a first dissipative brace secured to the structural element in a first position; a second dissipative brace secured to the structural element in a second position opposite the first position relative to the structural element, each of the first dissipative brace and the second dissipative brace comprising a respective:first mounting plate configured for mounting to the structure, the first mounting plate supporting a first bearing plate defining a first opening;first coupling member having a pair of opposed ends, first end of the first coupling member supporting a second bearing plate defining a second opening, a second end of the first coupling member supporting a third bearing plate defining a third opening;second coupling member having a respective pair of opposed ends, a respective first end of the second coupling member supporting a fourth bearing plate defining a fourth opening, a respective second end of the second coupling member supporting a fifth bearing plate defining a fifth opening;second mounting plate configured for mounting to the structure, the second mounting plate supporting a sixth bearing plate defining a sixth opening; and plurality of mechanical fasteners securing selected ones of the coupling members and mounting plates to one another in positions in which respective bearing plates abut one another, a first mechanical fastener of the plurality of mechanical fasteners passing through the first opening of the first mounting plate and the second opening of the first coupling member, a second mechanical fastener of the plurality of mechanical fasteners passing through the third opening of the first coupling member and the fourth opening of the second coupling member, a third mechanical fastener of the plurality of mechanical fasteners passing through the fifth opening of the second coupling member and the sixth opening of the second mounting plate,each of the plurality of mechanical fasteners being tensioned to apply a compressive force to respective bearing plates to cause increased friction betweenATTORNEY DOCKET NO. 10859.051 W01-GSB the respective bearing plates during relative rotational motion thereof to dissipate via friction any seismic energy applied to the mechanical coupling to cause relative rotational motion between abutting bearing plates.

37. The structure of claim 36, wherein each mechanical fastener comprises a bolt and a nut, and wherein the mechanical fastener is tensioned to apply the compressive force by applying a rotational torque force to the nut on the bolt.

38. The structure of claim 36, wherein the first bearing plate comprises a pair of spaced flanges, and wherein the second bearing plate defines at least a first respective flange dimensioned to be received between flanges of the pair of spaced flanges of the first bearing plate.

39. The structure of claim 36, wherein the first bearing plate defines a first contact surface and the second bearing plate defines a second contact surface positioned to abut the first contact surface, and wherein at least one of the first contact surface and the second contact surface is textured to cause increased friction between the first and second contact surfaces, and therefore between the first and second bearing plates, during relative rotational motion of the first and second bearing plates about the mechanical fastener.

40. The structure of claim 36, wherein at least one of the first and second coupling members defines at least one additional opening, and wherein another of the first and second coupling members defines at least one arcuate slot positioned to align with the at least one additional opening, and the first and second coupling members are joined by a mechanical fastener via the first and second openings, wherein the dissipative brace further comprises a deformable element disposed within each arcuate slot, and at least one pin, each pin extending through the first and second members via the at least one additional opening and a respective arcuate slot, whereby relative rotational motion of the first and second coupling members cause each pin to traverse each respective arcuate slot and correspondingly deform the deformable element disposed therein, whereby additional seismic energy is dissipated by deformation of the deformable element.ATTORNEY DOCKET NO. 10859.051 W01-GSB41. A structure comprising a dissipative brace system operable to dissipate seismic energy during a seismic event, the structure comprising:at least one structural element configured to exhibit rocking motion during a seismic event;a dissipative brace system joined to each structural element, each dissipative brace system comprising:a first dissipative brace secured to the structural element in a first position;a second dissipative brace secured to the structural element in a second position opposite the first position relative to the structural element, each of the first dissipative brace and the second dissipative brace comprising a respective:first mounting plate configured for mounting to the structure, the first mounting plate supporting a first bearing plate defining a first opening;first coupling member having a pair of opposed ends, first end of the first coupling member supporting a second bearing plate defining a second opening, a second end of the first coupling member supporting a third bearing plate defining a third opening;second coupling member having a respective pair of opposed ends, a respective first end of the second coupling member supporting a fourth bearing plate defining a fourth opening, a respective second end of the second coupling member supporting a fifth bearing plate defining a fifth opening;second mounting plate configured for mounting to the structure, the second mounting plate supporting a sixth bearing plate defining a sixth opening; andplurality of mechanical fasteners securing selected ones of the coupling members and mounting plates to one another in positions in which respective bearing plates abut one another, a first mechanical fastener of the plurality of mechanical fasteners passing through the first opening of the first mounting plate and the second opening of the first coupling member, a second mechanical fastener of the plurality of mechanical fasteners passing through the third opening of the first coupling member and the fourth opening of theATTORNEY DOCKET NO. 10859.051 W01-GSB second coupling member, a third mechanical fastener of the plurality of mechanical fasteners passing through the fifth opening of the second coupling member and the sixth opening of the second mounting plate,each of the plurality of mechanical fasteners being tensioned to apply a compressive force to respective bearing plates to cause increased friction between the respective bearing plates during relative rotational motion thereof to dissipate via friction any seismic energy applied to the mechanical coupling to cause relative rotational motion between abutting bearing plates.

42. The structure of claim 41 , wherein each mechanical fastener comprises a bolt and a nut, and wherein the mechanical fastener is tensioned to apply the compressive force by applying a rotational torque force to the nut on the bolt.

43. The structure of claim 41 , wherein the first bearing plate comprises a pair of spaced flanges, and wherein the second bearing plate defines at least a first respective flange dimensioned to be received between flanges of the pair of spaced flanges of the first bearing plate.

44. The structure of claim 41 , wherein the first bearing plate defines a first contact surface and the second bearing plate defines a second contact surface positioned to abut the first contact surface, and wherein at least one of the first contact surface and the second contact surface is textured to cause increased friction between the first and second contact surfaces, and therefore between the first and second bearing plates, during relative rotational motion of the first and second bearing plates about the mechanical fastener.

45. The structure of claim 41 , wherein at least one of the first and second coupling members defines at least one additional opening, and wherein another of the first and second coupling members defines at least one arcuate slot positioned to align with the at least one additional opening, and the first and second coupling members are joined by a mechanical fastener via the first and second openings, wherein the dissipative brace further comprises a deformable element disposed within each arcuate slot, and at least one pin, each pin extending through the first and second members via the at least one additional opening and a respectiveATTORNEY DOCKET NO. 10859.051 W01-GSB arcuate slot, whereby relative rotational motion of the first and second coupling members cause each pin to traverse each respective arcuate slot and correspondingly deform the deformable element disposed therein, whereby additional seismic energy is dissipated by deformation of the deformable element.

46. A method for providing a seismic-energy resistant structure, the method comprising:mechanically coupling a mechanical linkage configured to carry a desired load without plastic deformation to the structure, the mechanical linkage comprising at least a first coupling member and a second coupling member mechanically interconnected to form a mechanical coupling operable to dissipate seismic energy by relative movement of the first and second coupling members due to friction therebetween.

47. The method of claim 46, wherein said mechanically coupling the mechanical linkage to the structure comprises:securing ends of the mechanical couplings to members of a frame.

48. The method of claim 46, wherein said mechanically coupling the mechanical linkage to the structure comprises:securing a first end of the mechanical couplings to a first member of a frame comprising a plurality of frame members; andsecuring a second end of the mechanical couplings to a second member of the frame.

49. The method of claim 46, wherein said mechanically coupling the mechanical linkage to the structure comprises tensioning a mechanical fastener that to apply a compressive force causing surfaces of the first and second coupling members to abut one another.

50. The method of claim 46, wherein said mechanically coupling the mechanical linkage to the structure comprises tensioning a mechanical fastener by applying a rotational torque force to a nut on a bolt.ATTORNEY DOCKET NO. 10859.051 WO1-GSB 51. The method of claim 46, wherein said mechanically coupling the mechanical linkage to the structure comprises securing ends of the mechanical couplings to at least one structural element configured to exhibit rocking motion during a seismic event.

52. The method of claim 51 , wherein said mechanically coupling the mechanical linkage to the structure comprises securing ends of the mechanical couplings to the at least one structural element at a first location, the method further comprising mechanically coupling a second mechanical linkage to the at least one structural element at a second location opposite the first location, the second mechanical linkage comprising at least a third coupling member and a fourth coupling member mechanically interconnected to form a second mechanical coupling operable to dissipate seismic energy by relative movement of the third and fourth coupling members due to friction therebetween.

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