Structural fuses, structures including the same, and methods to retrofit structures to include structural fuses

Abstract

An example structural fuse includes a first attachment region configured to be attached to a first structural element, a second attachment region configured to be attached to a second structural element, and at least one yielding region extending between the first and second attachment regions. The yielding region exhibits a geometry that is selected to allow the structural fuse to maintain a strength thereof even as the structure fuse yields (e.g, buckles). For example, the yielding region exhibits a length, a minimum width, and a thickness and one or more of the length, minimum width, or thickness of the yielding region is selected to allow the structural fuse to maintain its original strength even as the structure fuse yields and buckles.

Description

STRUCTURAL FUSES, STRUCTURES INCLUDING THE SAME, AND METHODS TO RETROFIT STRUCTURES TO INCLUDE STRUCTURAL FUSESBACKGROUND

[0001] In order to resist wind and seismic loads, steel buildings may require braced frames, shear walls, moment frames, or other structures. Braced frames and shear walls tend to interfere with architectural features (open hallways, unobstructed windows, flexible floorplans), while moment frames are more accommodating. Moment frames rely on stiff and strong connections between the beams and columns to provide overall building stiffness and strength. However, moment frames tend to be more expensive than braced frames or shear walls because they are inherently less efficient and require more steel and expensive connections. It is desirable to develop steel moment frames that are economical to produce.

[0002] In addition, most moment frames are designed such that during earthquake loading the beams will yield and absorb damaging earthquake energy. This method of absorbing energy (beam yielding) can prevent building collapse and protect occupants but makes buildings difficult or impractical to repair after an earthquake.

[0003] To address these two issues (cost and repairability), some buildings include at least one structural fuse. Examples of such structural fuses include buckling retrained structural fuses. The buckling retrained structural fuses may be configured to allow portions thereof to move relative to structural elements while including buckling restraining elements that restrain buckling of the portions of the structural fuses that move relative to the structural elements. Examples of the buckling restraining elements includes bolts (e.g, positioned in elongated bolt holes), brackets, or separate plate(s) that sandwich the structural fuse between the structural element and the separate plate(s). These types of structural fuses may make structures more complicated to construct or inspect. It is desirable to have a fuse that can function without buckling-restraint bolts.SUMMARY

[0004] Embodiments are directed to structural fuses, structures including the same, methods of using and forming the same, and methods of retrofitting existing structures to include structural fuses. In an embodiment, a structural fuse is disclosed. The structureincludes a first attachment region, a second attachment region, and at least one yielding region extending between the first attachment region and the second attachment region. The at least one yielding region exhibits a length measured from the first attachment region to the second attachment region, a minimum width measured perpendicular to the length, the minimum width less than the length, and a thickness measured perpendicular to the length and the minimum width. The thickness is less than the minimum width. A ratio of the length to the thickness (length / thickness) is about 8 or less.

[0005] In an embodiment, a structure is disclosed. The structure includes a first structural element, a second structural element spaced from the first structural element by a gap, and at least one structural fuse. The at least one structural fuse includes a first attachment region attached to the first structural element, a second attachment region attached to the second structural element, and at least one yielding region extending between the first attachment region and the second attachment region. The structural fuse extends across the gap. The at least one yielding region exhibits a length measured from the first attachment region to the second attachment region, a minimum width measured perpendicular to the length, the minimum width less than the length, and a thickness measured perpendicular to the length and the minimum width. The thickness is less than the minimum width. A ratio of the length to the thickness (length / thickness) is about 8 or less.

[0006] In an embodiment, a method to retrofit a structure is disclosed. The method includes forming a slot extending through a majority of a single, modified structural element to separate the single, modified structural into a first structural element and a second structural element. The method also includes attaching a first attachment region of a structural fuse to the first structural element and a second attachment region of the structural fuse to the second structural element. The structural fuse extends across the slot. The structural fuse includes at least one yielding region between the first attachment region and the second attachment region.

[0007] Features from any of the disclosed embodiments may be used in combination with one another, without limitation. In addition, other features and advantages of the present disclosure will become apparent to those of ordinary skill in the art through consideration of the following detailed description and the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The drawings illustrate several embodiments of the present disclosure, wherein identical reference numerals refer to identical or similar elements or features in different views or embodiments shown in the drawings.

[0009] FIGS. 1A and IB are bottom plan and side elevational views, respectively, of a structure, according to an embodiment.

[0010] FIGS. 1C and ID are bottom plan and side elevational views, respectively, of the structure when an external compressive load is applied to the structure that is sufficiently large to yield the structural fuse, according to an embodiment.

[0011] FIG. IE is a graph illustrating the compressive stress-strain curve of a yielding region exhibiting a ratio of the length L to the thickness t of about 6 or less (solid line) relative to a yielding region of a conventional structural fuse exhibiting a ratio of the length to the thickness of about 11 (dashed line).

[0012] FIG. 2 is a plan view of a structural fuse, according to an embodiment.

[0013] FIGS. 3A-3C are side elevational, bottom plan, and top plan views, respectively, of a structure, according to an embodiment.

[0014] FIGS. 4A and 4B is a side elevational and bottom views, respectively, of a structure 400, according to an embodiment.

[0015] FIGS. 5A and 5B are side elevational and bottom views, respectively, of a structure, according to an embodiment.

[0016] FIG. 6 is a side elevational view of a structure, according to an embodiment.

[0017] FIGS. 7A and 7B are a side elevational and front elevational view of a structure, according to an embodiment.

[0018] FIGS. 8A and 8B are a side elevational and bottom plan view of a retrofitted structure, according to an embodiment.DETAILED DESCRIPTION

[0019] Embodiments are directed to structural fuses, structures including the same. methods of using and forming the same, and methods of retrofitting existing structures to include structural fuses. An example structural fuse includes a first attachment region configured to be attached to a first structural element, a second attachment region configured to be attached to a second structural element, and at least one yielding region extending between the first and second attachment regions. The yielding region exhibitsa geometry that is selected to allow the structural fuse to maintain a strength thereof even as the structure fuse yields (e.g., buckles). For example, the yielding region exhibits a length, a minimum width, and a thickness and one or more of the length, minimum width, or thickness of the yielding region is selected to allow the structural fuse to maintain most of its original strength even as the structure fuse yields and buckles.

[0020] The structural fuse may form part of a structure. The structure includes a first structural element and a second structural element. The first and second structural elements may include a column, a beam, a link beam, a coupling beam, a brace, a wall, a floor, foundation, or any other structural element. The first and second structural elements may include the same structures (e.g., the first and second structural elements are beams) or different structures (e.g, the first structural elements is a beam and the second structural element is a column) The first and second attachment regions of the structural fuse may be rigidly attached (e g, using bolts, rivets, welds, nails, etc.) to the first and second structural elements, respectively. It is noted that the structure may not include one or more buckling restraining elements (e.g, bolts, straps, additional plates, etc.) adjacent to the yielding region that are configured to prevent or at least inhibit buckling of the yielding region.

[0021] During use, a load (e.g., caused by earthquakes or wind) may be applied to the structure that includes the structural fuse. During loading, the portions of the first and second structural elements may move closer together or further apart. The movement of the first and second structural elements causes the first and second attachment regions of the structural fuse to likewise move due to the rigid attachments between the first and second structural elements and the first and second attachment regions, respectively, of the structural fuse. The yielding region of the structural fuse is configured to deform responsive to the first and second attachment regions moving which, in turn, allows the yielding region to absorb some of the load. When a sufficiently large compressive load is applied to the structure, the yielding region of the structural fuse may buckle. However, unlike conventional structural fuses, the strength of the yielding region of the structural fuse may negligibly decrease when the yielding region buckles due to the unique geometry (e.g., length, minimum width, thickness, etc.) of the yielding region.

[0022] The structural fuses disclosed herein exhibit one or more improvements over conventional structural fuses (i.e., elements in conventional structures that are designed to yield in a controlled manner to accommodate movements caused by earthquakes and wind loads). In an example, buckling of conventional structural fuses can cause asignificant decrease in the strength of the conventional structural fuses which may cause premature failure of the structure. As such, at least some conventional structural fuses include one or more buckling restraining elements configured to prevent or at least inhibit buckling of the conventional structural fuses which, in turn, allows the conventional structural fuses to retain most of the conventional structural fuses strength even after yielding. Examples of the buckling restraining elements include an additional plate that sandwiches the yielding region of the structural fuse between the additional plate and a structural element. However, the structural fuses disclosed herein are able to buckle without having a significant reduction in the strength thereof. As such, the structural fuses disclosed herein do not need to include buckling restraining elements to retain most of the structural fuse's strength after yielding. The structural fuses disclosed herein that do not include any buckling restraining elements may facilitate manufacturing and reduce cost of the structures including the structural fuses by decreasing the number of components necessary to form the structure and the labor required to form the structures compared to conventional structural fuses.

[0023] FIGS. 1A and IB are a bottom plan view and a side elevational view of a structure 100, according to an embodiment. The structure 100 includes a first structural element 102 and a second structural element 104. The first and second structural elements 102, 104 are spaced from each other by a gap 106. The structure 100 also has a structural fuse 108 that is attached to the first and second structural elements 102. 104.The structural fuse 108 is configured to attach the first and second structural elements 102, 104 together. The structural fuse 108 is also configured to preferentially yield when the first and second structural elements 102, 104 move relative to each other thereby preventing or at least inhibiting yielding of the first and second structural elements 102, 104. Yielding the structural fuse 108 instead of the first and second structural elements102, 104 may make repair of the structure 100 significantly easier.

[0024] The first and second structural elements 102, 104 may include any elements that may form part of the structure 100. In an example, as illustrated, the first and second structural elements 102, 104 may be plates. In an example, the first and second structural elements 102, 104 may include an I-beam, a hollow structural section (e.g, a square, rectangular, or circular hollow structural section), a concrete wall, or other structural element(s). In an example, the first and second structural elements 102, 104 may be aligned generally parallel (as shown) or perpendicular (as shown in FIG. 7A) to each other. In an example, the first and second structural elements 102, 104 may be a column,a beam, a link beam, a coupling beam, a brace, a wall, a floor, a foundation, or any other structural element.

[0025] The structural fuse 108 includes a first attachment region 110 and a second attachment region 112. The first and second attachment regions 110, 112 are spaced from each other, for example, along a longitudinal axis 114 of the structural fuse 108. For example, the first and second attachment regions 110. 112 may be spaced from each other by a yielding region 116. The first attachment region 110 is configured to be attached to the first structural element 102. For example, as shown, the first attachment region 110 is attached to a portion of the first structural element 102 that is adjacent or proximate to a terminal end 118 of the first structural element 102. That said, in some examples, the first attachment region 110 is attached to a portion of the second structural element 102 that is spaced from the terminal end 118. The second attachment region 112 is configured to be attached to a portion of the second structural element 104 that is adjacent to, proximate to, or spaced from a terminal end 120 of the second structural element 104.

[0026] The first and second attachment regions 110, 112 may be rigidly (z.e., nonmov ably) or non-ngidly (z.e., moveably) attached to the first and second structural elements 102, 104 using any suitable technique. In an embodiment, as illustrated, the first and second attachment regions 110, 112 may be rigidly attached to the first and second structural elements 102, 104 using one or more bolts 122 (as shown) or one or more rivets. In such an embodiment, the first structural element 102. the second structural element 104, the first attachment region 110, and second attachment region 1 12 may define one or more bolt holes 124 (shown using dashed lines in FIG. IB). The bolt holes 124 of the first structural element 102 and the bolt holes 124 of the first attachment region 110 may be aligned with each other and the bolt holes 124 of the second structural element 104 and the bolt holes 124 of the second attachment region 1 12 may be aligned with each other. The bolt holes 124 of the first structural element 102, the second structural element 104, the first attachment region 110, and the second attachment region 112 may be aligned in one or more rows that are generally parallel to the longitudinal axis 114 of the structure 100. For example, as illustrated, the bolt holes 124 may be aligned in two rows which, for example, may allow each row of bolt holes 124 to go through a flange with an intersecting web therebetween when the first and second structural elements 102, 104 are I-beams. However, it is noted that the bolt holes 124 may be arranged in a single row or three or more rows. In an embodiment, the first and second attachment regions 110, 112 may define oversized bolt holes (relative to the boltsreceived thereby) that allow the first and second attachment regions 110, 112 to be non- rigidly bolted to the first and second structural elements 102, 104. For example, the oversized bolt holes of the first and second attachment regions 110, 112 allow the bolts to slip a certain amount after the bolt friction force has been overcome.

[0027] In an embodiment, at least one of the first structural element 102 and the first attachment region 110 or the second structural element 104 and the second attachment region 112 may be attached together using a technique other than or in addition to one or more bolts or one or more rivets. For example, at least one of the first structural element 102 and the first attachment region 110 or the second structural element 104 and the second attachment region 112 may be attached together using a weld, clamps, straps, or any other suitable technique.

[0028] The structural fuse 108 is configured to form a gap 106 between the first and second structural elements 102, 104 when the first and second attachment regions 110, 112 are attached to the first and second structural elements 102, 104, respectively, and substantially no external load (e.g, caused by earthquakes or wind loads) is applied to the structure 100. The gap 106 allows the first and second structural elements 102, 104 to move closer to each other without contacting each other when a compressive load is applied to the structural fuse 108. Without the gap 106, the first and second structural elements 102, 104 may need to deform to accommodate the compressive load instead of or in addition to yielding the structural fuse 108. The gap 106 may be selected to be about 0.5 cm to about 1 cm, about 0.75 cm to about 1.25 cm, about 1 cm to about 1.5 cm, about 1.25 cm to about 1.75 cm, about 1.5 cm to about 2 cm, about 1.75 cm to about 2.25 cm, about 2 cm to about 2.5 cm, about 2.25 cm to about 2.75 cm. about 2.5 cm to about 3 cm. about 2.75 cm to about 3.25 cm, about 3 cm to about 3.5 cm, about 3.25 cm to about 3.75 cm, about 3.5 cm to about 4 cm, about 3.75 cm to about 4.5 cm, about 4 cm to about5 cm, about 4.5 cm to about 5.5 cm, about 5 cm to about 6 cm, about 5.5 cm to about 6.5 cm, about 6 cm to about 7 cm, about 6.5 cm to about 8 cm, about 7 cm to about 9 cm, about 8 cm to about 10 cm, about 9 cm to about 11 cm, about 10 cm to about 12 cm, about 1 1 cm to about 13 cm. about 12 cm to about 14 cm, or about 13 cm to about 15 cm. The gap 106 may be selected based on the amount of deformation that the structure 100 is configured to accommodate during severe loading. The amount of deformation that the structure 100 is configured to accommodate during severe loading may vary based on the type of structure. In an example, a structure that includes a beam-to-column connection(as shown in FIGS. 3A-4B) may include a gap of about 0.5 cm to about 7 cm, about 1 cm to about 5 cm, or about 1.5 cm to about 3.5 cm.

[0029] The structural fuse 108 includes a yielding region 116 positioned between the first attachment region 110 and the second attachment region 112. The yielding region 116 is configured to preferentially yield when a sufficiently large load is applied to the structure 100. In particular, the yielding region 116 is configured to yield before the first structural element 102. the second structural element 104, the first attachment region 110. and the second attachment region 112 yields, thereby preventing the need to repair a yielded first or second structural element 102, 104 and preventing weakening of the attachment between the first and second structural elements 102, 104 and the structural fuse 108.

[0030] The yielding region 116 of the structural fuse 108 may include one or more weakening features that are configured to weaken the yielding region 116 thereby causing the yielding region 116 to preferentially yield before the first structural element 102, the second structural element 104. the first attachment region 110, and the second attachment region 112 yields. In an embodiment, as illustrated in FIG. IB, the weakening features of the yielding region 116 includes one or more cutouts formed in the yielding region 116. The cutouts may extend completely through a thickness of the yielding region 116 (as shown) or through a portion of the thickness (e.g., the cutouts reduce the thickness of at least a portion of the yielding region 116). In an example, the cutouts extend inwardly from an outermost peripheral edge 130 of the structural fuse 108. The cutouts cause the yielding region 116 to exhibit a width WY (z.e., minimum width) that is less than the width WF (z'.e., maximum width) of the first attachment region 110 and less than the width Ws (z.e., maximum width) of the second attachment region 112, wherein the widths WY, WF, and Ws are measured perpendicular to the longitudinal axis 114 of the structural fuse108. Assuming the thickness of the structural fuse 108 is substantially constant (e.g., the structural fuse 108 is formed from a plate), the smaller width WY causes the yielding region 116 to exhibit larger stresses than first and second attachment regions 110, 112 thereby causing the yielding region 116 to preferentially yield.

[0031] In an example, the cutouts may be configured to cause the width WY of the yielding region 116 to be smaller than at least one of the width WF of the first attachment region 110 or the width Ws of the second attachment region 112 by about 0.25 cm or more, about 0.5 cm or more, about 0.75 cm or more, about 1 cm or more, about 1.25 cm or more, about 1.5 cm or more, about 2 cm or more about 2.5 cm or more, about 3 cm ormore, about 3.5 cm or more, about 4 cm or more, about 5 cm or more, about 6 cm or more, about 7 cm or more, about 8 cm or more, about 9 cm or more, about 12.5 cm or more, about 15 cm or more, about 17.5 cm or more, about 20 cm or more, about 25 cm or more, about 30 cm or more, about 35 cm or more, about 40 cm or more, or in ranges of about 0.25 cm to about 0.75 cm, about 0.5 cm to about 1 cm, about 0.75 cm or about 1.25 cm. about 1 cm to about 1.5 cm, about 1.25 cm to about 1.75 cm, about 1.5 cm to about 2 cm. about 1.75 cm to about 2.5 cm. about 2 cm to about 3 cm. about 2.5 cm to about 3.5 cm, about 3 cm to about 4 cm, about 3.5 cm to about 5 cm, about 4 cm to about 6 cm, about 5 cm to about 7 cm, about 6 cm to about 8 cm, about 7 cm to about 9 cm, about 8 cm to about 10 cm, about 9 cm to about 12.5 cm, about 10 cm to about 15 cm, about 12.5 cm to about 17.5 cm, about 15 cm to about 20 cm. about 17.5 cm to about 25 cm, about 20 cm to about 30 cm, about 25 cm to about 35 cm, or about 30 cm to about 40 cm. The width WY may be about 0.5 cm or more, about 0.75 cm or more, about 1 cm or more, about 1.25 cm or more, about 1.5 cm or more, about 2 cm or more about 2.5 cm or more, about 3 cm or more, about 3.5 cm or more, about 4 cm or more, about 5 cm or more, about 6 cm or more, about 7 cm or more, about 8 cm or more, about 9 cm or more, about12.5 cm or more, about 15 cm or more, about 17.5 cm or more, about 20 cm or more, about 25 cm or more, about 30 cm or more, or in ranges of about 0.25 cm to about 0.75 cm. about 0.5 cm to about 1 cm, about 0.75 cm or about 1.25 cm, about 1 cm to about 1.5 cm. about 1.25 cm to about 1.75 cm, about 1.5 cm to about 2 cm, about 1.75 cm to about2.5 cm, about 2 cm to about 3 cm, about 2.5 cm to about 3.5 cm, about 3 cm to about 4 cm, about 3.5 cm to about 5 cm, about 4 cm to about 6 cm, about 5 cm to about 7 cm, about 6 cm to about 8 cm, about 7 cm to about 9 cm, about 8 cm to about 10 cm, about 9 cm to about 12.5 cm, about 10 cm to about 15 cm, about 12.5 cm to about 17.5 cm, about 15 cm to about 20 cm, about 17.5 cm to about 25 cm, or about 20 cm to about 30 cm. In an example, the cutouts may be configured to cause the width WY of the yielding region 116 to be smaller than at least one of the width WF of the first attachment region 110 or the width Ws of the second attachment region 112 by about 1% to about 5%, about 2.5 % to about 7.5%. about 5% to about 10%, about 7.5% to about 15%. about 10% to about 20%, about 15% to about 25%, about 20% to about 30%, about 25% to about 35%, about30% to about 40%, about 35% to about 45%, about 40% to about 50%, about 45% to about 55%. about 50% to about 60%, about 55% to about 65%, about 60% to about 70%, about 65% to about 75%. about 70% to about 80%. or about 75% to about 85%. The difference between the width WY of the yielding region 116 and the widths WF, WS of thefirst and second attachment regions 110, 112 may depend on the size of the structure 100, the maximum expected movement between the first and second structural elements 102, 104 when a severe load is applied to the structure 100, and the desired load at which the yielding region 116 yields.

[0032] Generally, the width WY of the yielding region 116 is generally constant along an entire length L of the yielding region 116. However, it is noted that the width WY of the yielding region 116 may vary. In an example, the comers 129 of the yielding region 1 16 at or near at least one of the first attachment region 110 or the second attachment region 112 may be rounded. In an example, the width WY of the yielding region 116 may vary' to better control the portion of the yielding region 116 that initially yields when the load is applied to the structural fuse 108. In such an example, the width WY of the yielding region 116 may be generally constant except for the portions of the yielding region 116 formed by the round comers 129.

[0033] The yielding region 116 also exhibits a length L measured between the first and second attachment regions 110, 112. For example, the length L may be measured parallel to the longitudinal axis 114 of the structural fuse 108 and measured perpendicular to the width WY. The length L may be greater than the width WY. The length L may be selected to be about 2.5 cm or greater, such as about 5 cm or greater, about 10 cm or greater, about 15 cm or greater, about 20 cm or greater, about 25 cm or greater, about 30 cm or greater, about 35 cm or greater, about 40 cm or greater, about 45 cm or greater, about 50 cm or greater, about 60 cm or greater, about 70 cm or greater, or in ranges of about 2.5 cm to about 10 cm, about 5 cm to about 15 cm, about 10 cm to about 20 cm, about 15 cm to about 25 cm, about 20 cm to about 30 cm, about 25 cm to about 35 cm, about 30 cm to about 40 cm, about 35 cm to about 45 cm, about 40 cm to about 50 cm, about 45 cm to about 60 cm, or about 50 cm to about 70 cm. The size of the length L of the yielding region 116 may be selected based on the size of the structure 100 and the size of the gap 128. For example, increasing the size of the structure 100 or the gap 128 may require the length L to be increased. Also, as discussed in more detail below, the length L may depend on the geometry (e.g, width WY. thickness t. and average radius of curvature R) of the structural fuse 108.

[0034] The yielding region 116 further exhibits a thickness t measured perpendicular to the length L and the width WY. The thickness t may be smaller than the length L and the width WY. The thickness t may be selected to be 0.3 cm or greater, such as about 0.5 cm or greater, about 0.75 cm or greater, about 1 cm or greater, about 1.25 cm or greater,about 1.5 cm or greater, about 2 cm or greater, about 2.5 cm or greater, about 3 cm or greater, about 3.5 cm or greater, about 4 cm or greater, about 4.5 cm or greater, about 5 cm or greater, about 5.5 cm or greater, about 6 cm or greater, about 6.5 cm or greater, about 7 cm or greater, about 8 cm or greater, about 9 cm or greater, about 10 cm or greater, or in ranges of about 0.3 cm to about 0.75 cm, about 0.5 cm to about 1 cm, about0.75 cm to about 1.5 cm. about 1 cm to about 2 cm, about 1.5 cm to about 2.5 cm, about 2 cm to about 3 cm, about 2.5 cm to about 3.5 cm, about 3 cm to about 4 cm, about 3.5 cm to about 4.5 cm, about 4 cm to about 5 cm, about 4.5 cm to about 5.5 cm, about 5 cm to about 6 cm, about 5.5 cm to about 6.5 cm, about 6 cm to about 7 cm, about 6.5 cm to about 8 cm, about 7 cm to about 9 cm, or about 8 cm to about 10 cm. The thickness t of the yielding region 116 may be selected based on the size of the structure 100 and the size of the gap 128. For example, increasing the size of the structure 100 or the gap 128 may require the thickness t to be increased. The thickness t may also be selected based on the loads expected to be applied to the structure 100 and the desired load at which the yielding region 116 yields since increasing the thickness t increases the load at which the yielding region 116 yields. Also, as discussed in more detail below, the thickness t may depend on the geometry (e.g., width WY, length L, and average radius of curvature R) of the structural fuse 108.

[0035] In an example, as shown, one or more comers 129 formed by the cutout are rounded. The comers 129 are rounded when the comers 129 exhibit an average radius of curvature R that is greater than 0.25 cm. The rounded comers of the cutout prevent or at least inhibit the formation of stress concentrators which may cause the yielding region 116 to prematurely yield. Further, comers formed by the cutout are typically close to the first and second attachment regions 110, 112 and such stress concentrators may cause the first and second attachment regions 110, 112 to yield instead of or in addition to the yielding region 116. In a particular example, the rounded comers do not extend to the outermost peripheral edge 130. Instead, the cutout may be defined by a portion (e.g., a linear portion extending perpendicular to the longitudinal axis 114 and / or a rounded or chamfered comer) extending from the rounded comer 129 to the outermost peripheral edge 130. In an example, any comers formed by the cutout are not rounded.

[0036] In an example, the comers 129 may be rounded and exhibit an average radius of curvature R that is about 0.3 cm or greater, as about 0.5 cm or greater, about 0.75 cm or greater, about 1 cm or greater, about 1.25 cm or greater, about 1.5 cm or greater, about 2 cm or greater, about 2.5 cm or greater, about 3 cm or greater, about 3.5 cm or greater,about 4 cm or greater, about 4.5 cm or greater, about 5 cm or greater, about 5.5 cm or greater, about 6 cm or greater, about 6.5 cm or greater, about 7 cm or greater, about 8 cm or greater, about 9 cm or greater, about 10 cm or greater, or in ranges of about 0.25 cm to about 0.5 cm, about 0.3 cm to about 0.75 cm, about 0.5 cm to about 1 cm, about 0.75 cm to about 1.5 cm, about 1 cm to about 2 cm, about 1.5 cm to about 2.5 cm, about 2 cm to about 3 cm, about 2.5 cm to about 3.5 cm, about 3 cm to about 4 cm, about 3.5 cm to about 4.5 cm, about 4 cm to about 5 cm, about 4.5 cm to about 5.5 cm. about 5 cm to about 6 cm, about 5.5 cm to about 6.5 cm, about 6 cm to about 7 cm, about 6.5 cm to about 8 cm, about 7 cm to about 9 cm, or about 8 cm to about 10 cm. The average radius of curvature of the comers 129 may be selected based on the geometry of the structural fuse 108.

[0037] The yielding region 116 may exhibit a geometry that inhibits buckling of the yielding region 116 and, if buckling does occur, allows the yielding region 116 to maintain its strength to prevent failure of the structure 100. It has been found that such geometry of the yielding region 116 is dependent on the ratio of the length L, the width WY, the thickness t, and the average radius of curvature R. In particular, it has been found that the geometry of the yielding region 116 that prevents buckling of the yielding region 116 and / or maintains the strength of the yielding region 116 after buckling is most dependent on the ratio of the length L, the width WY. and the average radius of curvature R relative to the thickness t and. even more particularly, on the ratio of the length L relative to the thickness t. Although the discussion provided below focuses on these particular ratios, it is noted that other ratios (e.g., the ratio of the length L relative to the width WY or the average radius of curvature R) may also prevents buckling of the yielding region 116 while also maintaining the strength of the yielding region 116 after buckling.

[0038] In an embodiment, the yielding region 116 exhibits a ratio of the length L to the thickness t (length L / thickness t) that is about 8 or less, about 7 or less, about 6 or less, about 5 or less, about 4 or less, about 3 or less, about 2 or less, or in ranges of about 1 to about 2, about 1.5 to about 2.5, about 2 to about 3, about 2.5 to about 3.5. about 3 to about 4, about 3.5 to about 4.5, about 4 to about 5, about 4.5 to about 5.5, about 5 to about 6, about 5.5 to about 6.5, about 6 to about 7, about 6.5 to about 7.5, or about 7 to about 8. The yielding region 116 exhibiting any of these ratios will be relatively thicker than at least some conventional structural fuses, wherein such conventional structural fuses exhibit a ratio of the length to the thickness of about 1 1 or more. It has been found thatthe ratio of the length L to the thickness t has a significant effect on the ability of the yielding region 116 to maintain the strength thereof after buckling.

[0039] FIG. IE demonstrates that that the ratio of the length L to the thickness t has a significant effect on the ability of the yielding region 116 to maintain the strength thereof after buckling. For example, FIG. IE is a graph illustrating the compressive stress-strain curve of a yielding region 116 exhibiting a ratio of the length L to the thickness t of about 6 or less (solid line) relative to a yielding region of a conventional structural fuse exhibiting a ratio of the length to the thickness of about 1 1 (dashed line). As shown in FIG. IE, both the yielding region 116 and the yielding region of the conventional structural fuse exhibit an elastic deformation region (the area to the right of the X) where their respective lines are generally linear. The behavior of both the yielding region 116 and the yielding region of the conventional structural fuse in the elastic deformation region are generally similar. Increasing the load applied to the yielding region 116 and the yielding region of the conventional structural fuses causes the yielding region 116 and the yielding region of the conventional structural fuses to enter the plastic deformation region (the area left of the X) where the yielding region 116 and the yielding region of the conventional structural fuses begin to buckle. As shown in FIG. IE, the yielding region 116 exhibits a higher strength than the yielding region of the conventional structural fuse as a function of strain in the plastic deformation region. Further, the yielding region of the conventional structural fuse exhibits a maximum strength and the strength (z.e., the load required to obtain the particular strain) of the yielding region of the conventional structural fuse decreases as the strain increases. However, the strength of the yielding region 116 plateaus as the strain continues to increase. In other words, unlike the conventional structural fuses, the yielding region 116 exhibiting a ratio of about 6 or less maintains or at least substantially maintains the strength thereof as the yielding region 116 buckles.

[0040] Although not shown in FIG. IE, it is noted that the yielding region 116 exhibiting a ratio of the length L to the thickness t of about 6 to about 8 exhibits a strength that is also significantly greater than the yielding region of the conventional structural fuse. The yielding region 116 exhibiting a ratio of the length L to the thickness t of about 6 to about 8 may exhibit a maximum strength and the strength of the yielding region exhibiting the length L to the thickness t of about 6 to about 8 may decrease as the strain increases depending on the material forming the structural fuse 108 and the other geometry of the yielding region 116.

[0041] In an embodiment, the yielding region 116 exhibits a ratio of the width WY to the thickness t (width Wy / thickness t) that is about 6 or less, about 5 or less, about 4 or less, about 3 or less, about 2 or less, or in ranges of about 1.5 to about 2, about 1.5 to about 2.5, about 2 to about 3, about 2.5 to about 3.5, about 3 to about 4, about 3.5 to about 4.5, about 4 to about 5, about 4.5 to about 5.5, about 5 to about 6, about 5.5 to about 6.5, about 6 to about 7, about 6.5 to about 7.5, or about 7 to about 8. Again, the yielding region 116 exhibiting any of these ratios will be relatively thicker than conventional structural fuses. It has been found that the ratio of the width WY to the thickness t has a significant effect on the ability of the yielding region 116 to resist buckling and maintain the strength thereof after buckling.

[0042] In an embodiment, the yielding region 116 exhibits a ratio of the average radius of curvature R to the thickness t (average radius of curvature R / thickness t) that is about 4 or less, about 4 or less, about 3 or less, about 2 or less, about 1 or less, about 0.5 or less, or in ranges of about 0.5 to about 1, about 0.75 to about 1.5, about 1 to about 2, about 1.5 to about 2.5, about 2 to about 3, about 2.5 to about 3.5, or about 3 to about 4. It has been found that the ratio of the average radius of curvature R to the thickness t has a significant effect on the abili t of the yielding region 116 to resist buckling and maintain the strength thereof after buckling.

[0043] It is noted that the yielding region 116 may exhibit other ratios that effect the ability of the yielding region 116 to resist buckling and / or maintain the strength of the yield region 1 16 after buckling. Examples of such ratios include the ratio of the length L to the width WY, the ratio of the length L to the average radius of curvature R, and the ratio of the width WY to the average radius of curvature R. These ratios may be determined using the lengths L, widths WY. and average radius of curvatures R discussed above.

[0044] The structural fuse 108 may be formed from any suitable material. In an example, the structural fuse 108 may include steel (e.g, standard structural steel, stainless steel, or other steel alloys), aluminum, brass, bronze, one or more plastics, one or more composites, or combinations thereof. It is noted that the particular geometries of the yielding region 116 that resists buckling and / or maintains its strength after buckling may depend, in part, on the composition of the structural fuse 108. For example, the maximum ratio of the length L to the thickness t that allows the yielding region 116 to resist buckling and / or maintain its strength after buckling depends, in part, on the elastic modulus (Young’s modulus) of the material forming the structural fuse. For instance, themaximum ratio of the length L to the thickness t may decrease as the elastic modulus of the material is decreased.

[0045] The structural fuse 108 may include weakening features other than or in addition to the cutouts. Examples of other weakening features includes selectively thinning the yielding region 116 relative to the first and second attachment regions 110, 112 and forming the yielding region 116 from a weaker material (z.e., a material exhibiting a yielding stress) that is less than a material forming the first and second attachment regions 1 12, 112.

[0046] The yielding region 116 may be configured to yield when a tensile or compressive load (e.g., not a shear load) is applied thereto. FIGS. IB- ID illustrate how the structural fuse 108 absorbs energy when a load is applied to the structure 100. FIG. IB illustrates the structure 100 when no external load is applied to the structure 100. When no external load is applied to the structure 100, the first and second structural elements 102, 104 are spaced from each other by the gap 106 (illustrated in FIG. IB, partially obscured in FIG. 1A). FIGS. 1C and ID are bottom and side views of the structure 100 when an external compressive load F is applied to the structure 100 that is sufficiently large to yield the structural fuse 108, according to an embodiment. The compressive load F causes the first and second structural elements 102, 104 to move closer together. Moving the first and second structural elements 102, 104 closer together also causes the first and second attachment regions 110, 112 of the structural fuse 108 to move closer together due to the attachment (e g., rigid attachment) between the first structural element 102 and the first attachment region 110 and the attachment (e.g., rigid attachment) between the second structural element 104 and the second attachment region 112. Moving the first and second attachment regions 110, 112 closer together may be sufficient to cause the yielding region 116 to yield (e.g., buckle), as shown in FIG. 1C using cross-hatching and in FIG. ID. Yielding the yielding region 116 causes the structural fuse 108 to absorb at least some of the energy applied to the structure 100. Also, the second structural element 104 is able to move relative to the yielding region 116 (e.g.. due to the buckling of the yielding region 116). It is noted that the strength of the yielding region 116 and the structural fuse 108 as a whole is maintained or substantially maintained even as the yielding region 116 yields due to the geometry' of the yielding region 116.

[0047] Although FIGS. 1C and ID illustrates a compressive load F being applied to the structure 100, it is noted that a tensile load may be applied to the structure 100. Thetensile load causes the first and second structural elements 102, 104 to move further apart. Moving the first and second structural elements 102, 104 apart also causes the first and second attachment regions 110, 112 of the structural fuse 108 to move further apart due to the attachment (e.g., rigid attachment) between the first structural element 102 and the first attachment region 110 and the attachment (e.g. , rigid attachment) between the second structural element 104 and the second attachment region 112. Moving the first and second attachment regions 110, 112 apart may be sufficient to cause the yielding region 1 16 to yield. Yielding the yielding region 116 causes the structural fuse 108 to absorb at least some of the energy applied to the structure 100. Also, the second structural element 104 is able to move relative to the yielding region 116.

[0048] The structures disclosed herein may include structural fuses that are different than the structural fuse 108 illustrated in FIGS. 1A-1D. For example, FIG. 2 is a plan view of a structural fuse 208, according to an embodiment. Except as otherwise disclosed herein, the structural fuse 208 is the same or substantially similar to any of the structural fuses disclosed herein. For example, the structural fuse 208 includes a first attachment region 210 that is configured to be rigidly attached to a first structural element (not shown), and a second attachment region 212 that is configured to be rigidly attached to the second structural element (not shown).

[0049] The structural fuse 208 includes a plurality of yielding regions 216, such as a first yielding region 216a and a second yielding region 216b. The structural fuse 208 defines at least one elongated hole 232 positioned between and separating adjacent ones of the plurality of yielding regions 216. The elongated hole 232 extends at least partially between the first attachment region 210 and the second attachment region 212 (e.g, from the first attachment region 210 to the second attachment region 212). Each of the plurality of yielding regions 216 exhibit any of the geometries disclosed herein, such as any of the lengths L, widths WY, thickness t, average radius of curvature R (if the yielding regions 216 include rounded comers), and any of the ratios disclosed herein.

[0050] Forming a plurality of yielding regions 216 in the structural fuse 208 allows the structural fuse 208 to exhibit a smaller thickness t than the structural fuse 108 while the yielding region 216 exhibits a collective width (e.g, the combined) width of the first and second yielding regions 216a, 216b that is similar to the width WY of the yielding region 116. Forming a plurality' of yielding regions 216 in the structural fuse 208 also allows the structural fuse 208 to attach two structural elements together even if one of the yielding regions 216 catastrophically fails.

[0051] As previously discussed, the structural fuses disclosed herein may be used in structures other than the structure 100 illustrated in FIGS. 1A-1D. FIGS. 3A-8B illustrate different structures that may include any of the structural fuses disclosed herein. Except as otherwise disclosed herein, the structures and structural fuses illustrated in FIGS. 3A-8B are the same as or substantially similar to any of the structures and structural fuses disclosed herein, respectively. It is noted that the structures illustrated in FIGS. 3A-8B are merely examples of structures that may include the structural fuses disclosed herein. In other words, the structural fuses disclosed herein may be used in structures other than the structures illustrated in FIGS. 1A-1D and 3A-8B.

[0052] FIGS. 3A-3C are side elevational, bottom plan, and top plan views, respectively, of a structure 300, according to an embodiment. The structure 300 is an example of a beam-to-column connection. The structure 300 includes a column 302 (z.e., a first structural element) and a beam 304 (z.e., a second structural element). In the illustrated embodiment, the column 302 and beam 304 are illustrated as being I-beams. However, it is noted that the column 302 and the beam 304 may include plates, hollow structural sectionals, T-beams, or any other suitable structural element.

[0053] Referring to FIGS. 3A and 3B, the column 302 and the beam 304 are attached together using a structural fuse 308. The structural fuse 308 may include any of the structural fuses disclosed herein. The structural fuse 308 includes a first attachment region 310. a second attachment region 312, and a yielding region 316 extending between the first and second attachment regions 310, 312. The first attachment region 310 is rigidly attached (either directly or indirectly) to the column 302, such as to a flange 336 of the column 302. The second attachment region 312 is rigidly attached (e.g, directly or indirectly) to the beam 304, such as to a flange 340 of the beam 304. The structural fuse 308 is moveably attached to the beam 304. The yielding region 316 may exhibit any of the geometries disclosed herein.

[0054] In an example, not shown, the first attachment region 310 is directly rigidly attached to the column 302 using, for instance, a weld or one or more bolts (e.g., the first attachment region 310 is an angle). In an example, as shown, the first attachment region 310 is indirectly rigidly attached to the column 302, for instance, using a first plate 338.The first plate 338 may be attached to the column 302 (e.g, using a weld, bolts, etc.) before assembling the structure 300 in the field which may facilitate assembly of the structure 300. In an example, the second attachment region 312 is directly or indirectly attached to the beam 304.

[0055] In an embodiment, as shown, the structural fuse 308 may be attached to the bottom side (e.g, the bottom flange 340) of the beam 304. Attaching the structural fuse 308 to the bottom side of the beam 304 may facilitate inspecting, repairing, and / or replacing of the structural fuse 308. For example, floors are typically positioned on the top side (e.g., top flange 342) of the beam 304. The floors may include concrete or other elements that make accessing the top side of the beam 304 difficult. Meanwhile, a ceiling is generally positioned adjacent to the bottom side of the beam 304. The ceiling may include drop ceiling tiles or include another material that is easier to remove than the floor. Thus, attaching the structural fuse 308 to the bottom side of the beam 304 makes accessing the structural fuse 308 easier which facilitate inspecting, repairing, and replacing the structural fuse 308.

[0056] Referring to FIGS. 3A and 3C, the top side (e.g., top flange 342) of the second structural element 304 may be attached to the column 302. In an embodiment, as illustrated, the top side of the beam 304 is attached to the column 302 using a plate 344 or another element other than a structural fuse 308 that is not configured to preferentially yield like the structural fuse 308. As previously discussed, the top side of the beam 304 may be difficult to access and thus, attaching the top side of the beam 304 using an element other than a structural fuse 308 reduces the likelihood that the top side of the beam 304 needs to be accessed to repair the structure 300. In an embodiment, the top side of the beam 304 may be attached to the column 302 using a structural fuse. In an embodiment, the flange 336 of the column 302 may be attached to the web 346 of the beam 304 using a shear tab 348.

[0057] Due to the structural fuse 308, the structure 300 exhibits adequate stiffness and is able to accommodate large deformations without losing strength. The structure 300 may also be a fully restrained connection since the plate 338 and the plate 344 may be welded to the column 302. The structural fuse 308 also allows the structure 300 to be more easily repaired compared to other conventional beam-to-column connections.

[0058] FIGS. 4A and 4B is a side elevational and bottom views, respectively, of a structure 400, according to an embodiment. The structure 400 is an example of a beam- to-column connection. Except as otherwise disclosed herein, the structure 400 is the same as or substantially similar to the beam-to-column connection illustrated in FIGS. 3A-3C. For example, the structure 400 includes a column 402 (z.e., a first structural element) and a beam 404 (z.e., a second structural element). In the illustrated embodiment, the column 402 and beam 404 are illustrated as being I-beams. However, itis noted that the column 402 and the beam 404 may include plates, hollow structural sectionals, T-beams, or any other suitable structural element.

[0059] The structure includes a connecting beam 433 attached to the column 402 that is distinct from the beam 404. The connecting beam 433 may be an I-beam including a top flange 434, a bottom flange 436, and a web 438 extending between the top flange 434 and the bottom flange 436. That said, it is noted that the connecting beam 433 may be another type of structural element, such as a hollow structural section or a T-beam. Generally, the connecting beam 433 may be the same type of structural element as the beam 404.

[0060] The connecting beam 433 is attached to the column 402 using any suitable technique. In an example, the connecting beam 433 is directly attached to the column 402, such as via welding. In such an example, one or more of the top flange 434, the bottom flange 436, or the web 438 may be welded or otherwise directly attached to the column 402. In an example, the connecting beam 433 may be indirectly attached to the column 402, such as using one or more angles (e g., angles bolted, weld, or otherwise attached to the column 402 and the connecting beam 433), a shear plate, or any other suitable connection.

[0061] The connecting beam 433 acts as an intermediary' structure that allows the column 402 and the beam 404 to be attached together. In other words, the beam 404 may be attached to the connecting beam 433 which, in turn, indirectly attaches to the beam 404 to the column 402. The beam 404 may be attached to the connecting beam 433 using any suitable technique. In an example, the top flange 442 of the beam 404 is attached to the top flange 434 of the connecting beam 433 using a plate 444. The plate 444 may be attached to both the top flanges 434, 442 using any suitable technique, such as bolts (as shown), welds, etc. The top flanges 434, 442 may be attached together such that there is a gap 428 therebetween to accommodate movement between the beam 404 and the connecting beam 433. In an example, the web 446 of the beam 404 is attached to the web 438 of the connecting beam 433. The webs 438 may be attached to each other using any suitable technique. In a particular example, as shown, the web 438 of the connecting beam 433 is configured to form a shear plate that is attached to the web 446 of the beam 404. In such an example, the web 438 may extend further from the column 402 than the top flange 434 and the bottom flange 436 of the connecting beam 433 thereby allowing a portion of the web 438 of the connecting beam 433 to extend along a portion of the web 446 of the beam 404. The portion of the web 438 that extends along a portion of the web446 may be attached together using bolts (as shown) or any other suitable technique. At least one of the web 438 may be off-center relative to the top and bottom flanges 434, 436, the connecting beam 433 may be off-center relative to the column 402, or the beam 404 may be off-center relative to the column 402 to allow a portion of the web 438 to extend along a portion of the web 446 of the beam 404. In an example, the bottom flange440 of the beam 404 may be attached to the bottom flange 436 of the connecting beam 433 using the structural fuse 408. In such an example, the bottom flanges 436. 440 may be spaced from each other by the gap 428 and the yielding region 416 of the structural fuse 408 may span the gap 428.

[0062] It is noted that the beam 404 may be attached to the connecting beam 433 using any other suitable technique. In an example, the top flanges 434, 442 may be attached together using a structural fuse instead of or in addition to the bottom flanges 436, 440.

[0063] The beam-to-column connection illustrated in FIGS. 4A and 4B may be simpler to manufacture than the beam-to-column connection illustrated in FIGS. 3A-3C, especially when manufactured off-site, since the beam-to-column connection illustrated in FIGS. 4A and 4B has fewer components. The beam-to-column connection illustrated in FIGS. 3A-3C may be lighter than the beam-to-column connection illustrated in FIGS. 4 A and 4B.

[0064] FIGS. 5A and 5B are side elevational and bottom views, respectively, of a structure 500, according to an embodiment. The structure 500 is an eccentrically braced frame. The structure 500 includes a column 502 ( / .<?., a first structural element), a beam 504 (z.e., a second structural element), a link beam 550 (i.e., a third structural element), and a brace 552 (i.e.. a fourth structural element). The brace 552 is attached to the rest of the structure 500 i.e., the beam 504) at some distance from the column 502 and the link beam 550 extends between the beam 504 to the column 502. It is noted that the beam 504 may extend past the brace 552 thereby providing a location for the structural fuse 508 to be attached.

[0065] The structure 500 includes at least one structural fuse 508. Except as otherwise disclosed herein, the structural fuse 508 may be the same as or substantially similar to any of the structural fuses disclosed herein. The at least one structural fuse 508 may attach the column 502, the beam 504, and link beam 550 together. The at least one structural fuse 508 may also maintain a first gap 506a between the column 502 and the link beam 550 when no external load is applied to the structure 500 thereby allowingmovement between the column 502 and the link beam 550 when a load is applied to the structure 500. In the illustrated embodiment, the first gap 506a is between the web 546 of the link beam 550 and the flange 536 of the column 502 and between the flange 540 of the link beam 550 and the plate 538 when the structural fuse 508 is indirectly attached to the column 502 using the plate 538. The at least one structural fuse 508 may also maintain a second gap 506b between the beam 504 and the link beam 550 when no external load is applied to the structure 500 thereby allowing movement between the beam 504 and the link beam 550 when a load is applied to the structure 500.

[0066] In an embodiment, as shown, the structure 500 includes a single structural fuse 508 that is configured to be attached to each of the column 502, the beam 504, and the link beam 506. In such an embodiment, the structural fuse 508 includes a first attachment region 510 that is configured to be rigidly attached to the column 502 (e.g., via a plate 538), a second attachment region 512 that is configured to be rigidly attached to the beam 504, and a third attachment region 554 positioned between the first and second attachment regions 510, 512 that is configured to be rigidly attached to the link beam 550.It is noted that the third attachment region 554 may be the same or substantially similar to any of the attachment regions disclosed herein. The structural fuse 508 includes a first yielding region 516a extending between the first and third attachment regions 510, 554 and a second yielding region 516b extending between the second and third attachment regions 512, 554. The first and second yielding regions 516a, 516b may exhibiting any of the geometries disclosed herein. In an embodiment, not shown, the structure 500 may include two or more structural fuses that attach the column 502, the beam 504, and the link beam 550 together. For example, in such an embodiment, the structure 500 may include a first structural fuse that attaches the column 502 to the link beam 550 and a second structural fuse that attaches the beam 504 to the link beam 550. It is noted that using only a single structural fuse 508 to attach each of the column 502, the beam 504, and the link beam 550 together requires less pieces (z.e., makes assembly of the structure 500 less complex and less likely to be installed incorrectly) than if first and second structural fuses are used to attach the column 502, the beam 504, and the link beam 550 together. However, using a single structural fuse 508 requires replacing the whole structural fuse 508 if only one yielding region yields whereas using the first and second structural fuses allows for a more targeted repair that wastes less material.

[0067] In an embodiment, the structural fuse 508 may be attached to the bottom sides of the beam 504 and the link beam 550 to facilitate replacement of the structural fuse 508after the structural fuse 508 yields, for reasons previously discussed. In such an embodiment, one or more elements may be attached to the top sides of the beam 504 and the link beam 550 to attach the column 502, the beam 504, and the link beam 550 together. The one or more elements may be configured to not preferentially yield such that repair of the one or more elements is unlikely. The one or more elements may include a first top plate 544a that attaches the column 502 to the top side of the link beam 550 and a second top plate 544b that attaches the top side of the beam 504 to the top side of the link beam 550. In an embodiment, the structure 500 may include a structural fuse attached to the top side of the beam 504 and the link beam 550 instead of or in addition to the structural fuse 508 attached to the bottom side of the beam 504 and the link beam 550.

[0068] The structural fuse 508 provides several advantages over conventional eccentrically braced frames. For example, the structural fuse 508 may accelerate construction of the eccentrically braced frame illustrated in FIGS. 5A and 5B compared to a fully-welded eccentrically braced frame. The structural fuse 508 may also result in better control of loads applied to the structure 500 compared to a conventional eccentrically braced frame. The structural fuse 508 further makes it easier to inspect and repair the structure 500 (e.g, after an earthquake) compared to a conventional eccentrically braced frames.

[0069] FIG. 6 is a side elevational view of a structure 600, according to an embodiment. The structure 600 is an example of concrete shear walls or concrete steel coupled walls. The structure includes a first wall 602 (i.e., a first structural element), a second wall 604 (<?.g, a second structural element), and a coupling beam 650 (z.e., a third structural element).

[0070] The structure 600 includes at least one structural fuse 608. Except as otherwise disclosed herein, the structural fuse 608 is the same as or substantially similar to any of the structural fuses disclosed herein (e.g, exhibits any of the geometries disclosed herein). The at least one structural fuse 608 may attach the first wall 602, the second wall 604, and coupling beam 650 together. The at least one structural fuse 608 may also maintain a first gap 606a between the first wall 602 and the coupling beam 650 when no external load is applied to the structure 600 thereby allowing movement between the first wall 602 and the coupling beam 650 when a load is applied to the structure 600. The at least one structural fuse 608 may also maintain a second gap 606b between the second wall 604 and the coupling beam 650 when no external load is applied to the structure 600 thereby allowing movement between the second wall 604 and the couplingbeam 650 when a load is applied to the structure 600. It is noted that the first and second gaps 606a, 606b include the gaps between the coupling beam 650 and the plates 638a, 638b.

[0071] In an embodiment, as shown, the structure 600 includes a single structural fuse 608 that is configured to be attached to each of the first w all 602, the second wall 604, and the coupling beam 650. In such an embodiment, the structural fuse 608 includes a first attachment region 610 that is configured to be rigidly attached to the first wall 602 (e.g., via a first bottom plate 638a), a second attachment region 612 that is configured to be rigidly attached to the second wall 604 (e.g., via a second bottom plate 638b), and a third attachment region 654 positioned between the first and second attachment regions 610, 612 that is configured to be rigidly attached to the coupling beam 650. The structural fuse 608 includes a first yielding region 616a extending between the first and third attachment regions 610, 654 and a second yielding region 616b extending between the second and third attachment regions 612, 654. In an embodiment, not shown, the structure 600 may include two or more structural fuses that attach the first wall 602, the second wall 604, and the coupling beam 650 together. For example, in such an embodiment, the structure 600 may include a first structural fuse that attaches the first wall 602 to the coupling beam 650 and a second structural fuse that attaches the second wall 604 to the coupling beam 650. It is noted that using only a single structural fuse 608 to attach the first wall 602. the second wall 604, and the coupling beam 650 together requires less pieces (z.e., makes assembly of the structure 600 less complex and less likely to be installed incorrectly) than if the first and second structural fuses are used to attach the first wall 602, the second wall 604, and the coupling beam 650 together. However, using a single structural fuse 608 requires replacing the whole structural fuse 608 if only one yielding region yields whereas using the first and second structural fuses allows for a more targeted repair that wastes less material.

[0072] In an embodiment, the structural fuse 608 may be attached to the bottom sides of the second wall 604 and the coupling beam 650 to facilitate replacement of the structural fuse 608 after the structural fuse 608 yields. In such an embodiment, one or more elements may be attached to the top sides of the second wall 604 and the coupling beam 650 to attach the first wall 602, the second wall 604, and the coupling beam 650 together. The one or more elements may be configured to not preferentially yield such that repair of the one or more elements is unlikely. The one or more elements may include a first top plate 644a that attaches the first wall 602 to the top side of the couplingbeam 650 and a second top plate 644b that attaches the top side of the second wall 604 to the top side of the coupling beam 650. In an embodiment, not shown, the structure 600 may include a structural fuse 608 attached to the top side of the second wall 604 and the coupling beam 650 instead of or in addition to the structural fuse 608 attached to the bottom side of the second wall 604 and the coupling beam 650.

[0073] The structural fuse 608 provides several advantages over conventional coupled concrete shear walls or concrete steel coupled walls. For example, the structural fuse 608 may accelerate construction of the structure 600 and may be easier to construct compared to conventional coupled concrete shear walls or concrete steel coupled walls. The structural fuse 608 also results in better control of loads applied to the structure 600 compared to conventional coupled concrete shear walls or concrete steel coupled walls. The structural fuse 608 further makes it easier to inspect and repair the structure 600 (e.g. , after an earthquake) compared to a conventional coupled concrete shear walls or concrete steel coupled walls.

[0074] FIGS. 7A and 7B are a side elevational and front elevational view of a structure 700, according to an embodiment. The structure 700 is an example of a framing structure or a shear wall, such as timber framing and a timber shear wall. The structure 700 includes a wall 702 (z.e., first structural element) and a floor 704 (z.e., a second structural element). It is noted that, in some embodiments, the wall 702 may be replaced with a column and / or the floor 704 may be replaced with a foundation.

[0075] The structure 700 includes a structural fuse 708. Except as otherwise disclosed herein, the structural fuse 708 may be the same as or substantially similar to any of the structural fuses disclosed herein. The structural fuse 708 may attach the w all 702 and the floor 704 together. The structural fuse 708 includes a first attachment region 710 that is configured to be rigidly attached to the wall 702 and a second attachment region 712 that is configured to be rigidly attached to the floor 704. Since the wall 702 and the floor 704 extend perpendicularly to each other, the structural fuse 708 has a 90° bend therein, such as between the yielding region 716 and the first attachment region 710 or the second attachment region 712. The structural fuse 708 also includes a yielding region 716 extending between the first and second attachment regions 710, 712.

[0076] The structures illustrated in FIGS. 3A to 7B are structures that include gaps between two separate and distinct structural elements, since such gaps allow the structural fuses to move closer together when a load is applied to the structure. Such structures may be structures that are initially designed to include the structural fuses disclosed herein ormay be designed to be used with conventional structural fuses. That said, the structural fuses disclosed herein (and even conventional structural fuses) may be used with structures that do not initially include a gap between structural elements. However, the structures that do not initially include a gap between the structural elements may need to be retrofitted to include a gap when used with the structural fuses disclosed herein or conventional structural fuses, such as the structural fuses disclosed in U.S. Patent Application No. 18 / 060,703, filed on December 1, 2021. the disclosure of which was incorporated herein.

[0077] FIGS. 8A and 8B are a side elevational and bottom plan view of a retrofitted structure 800, according to an embodiment. Except as otherwise disclosed herein, the retrofitted structure 800 may be the same as or substantially similar to any of the structures disclosed herein. For example, the structure 800 may be a beam-to-column structure that is similar to one or more of the beam-to-column structures illustrated in FIGS. 3A-4B. That said, it is noted that the features of the retrofitted structure 800 and the methods used to form the retrofitted structure 800 may be used in any of the other types of structures disclosed herein, or any other type of structure.

[0078] The retrofitted structure 800 includes an unmodified structural element 802 and a single, modified structural element 804. In the illustrated embodiment, the unmodified structural element 802 is a column (e.g, an I-beam) and the single, modified structural element 804 is a beam (e.g., an I-beam). The unmodified structural element 802 and the single, modified structural element 804 are attached together using any suitable attachment. For example, as shown, the structural elements 802, 804 are attached together using welds 870 and a shear plate 848.

[0079] To retrofit the structure 800, a slot 872 may be formed in the single, modified structural element 804. The slot 872 may extend through a majority of, but not completely through, the second structural element 804. For example, the second structural element 804 may be an I-beam having a bottom flange 840, a top flange 842, and a web 846 extending between the bottom flange 840 and the top flange 842. The slot 872 may be formed through one of the flanges (i.e.. the flange that the structural fuse 808 is attached to which is normally the bottom flange 840) and through at least a portion of(e.g, a majority of or all of) the web 846. The slot 872 does not extend into or does not extend through an entirety of the remaining flange (i.e., the flange that the structural fuse 808 is not attached to which is normally the top flange 842). The slot 872 may be formed using any suitable technique, such as with a laser, grinding, a cutting torch, or a saw.

[0080] The slot 872 separates the single, modified structural element 804 into a first structural element 874 and a second structural element 876. The first and second structural elements 874, 876 are separated from each other by the slot 872. In other words, the slot 872 forms the gap between the first and second structural elements 874, 876. The structural fuse 808 may be attached to the first and second structural elements874, 876 and may span across the slot 872. The portion of the single, modified structural element 804 that the slot 872 does not extend through basically acts as the plate (e.g. plate 344 of FIGS. 3A-3C and plate 444 of FIGS. 4A and 4B) that attaches the sides of the first and second structural elements 874, 876 opposite the structural fuse 808 together.

[0081] The retrofitted structure 800 may also include a shear plate 848 attached to the webs of the first and second structural elements 874. 876. In an embodiment, as shown, the shear plate 848 may include elongated bolt holes 878 configured to receive bolts 880, wherein the elongated bolt holes 878 exhibit a maximum lateral dimension that is greater than a diameter of the bolts 880. The elongated bolt holes 878 allows one or more of the first structural element 874 or the second structural element 876 to move relative to the shear plate 848, and the first and second structural elements 874, 876 move closer together or further apart.

[0082] During use, a load may be applied to the retrofitted structure 800. The slot 872 allows the portions of the first and second structural elements 874, 876 adjacent to the slot 872 to move closer together or further apart depending on whether the load is a compressive or tensile load. The structural fuse 808 may yield depending on the size of the load applied to the retrofitted structure 800, as previously discussed. The portion of the single, unmodified structural element 804 that the slot 872 does not extend through may act as a hinge that allows the first and second structural elements 874, 876 to move closer together or further apart.

[0083] While various aspects and embodiments have been disclosed herein, other aspects and embodiments are contemplated. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting.

[0084] Terms of degree e.g., "‘about / ’ “substantially,” “generally,” etc.) indicate structurally or functionally insignificant variations. In an example, when the term of degree is included with a term indicating quantity, the term of degree is interpreted to mean ± 10%, ±5%, or ±2% of the term indicating quantity'. In an example, when the term of degree is used to modify a shape, the term of degree indicates that the shape being modified by the term of degree has the appearance of the disclosed shape. For instance,the term of degree may be used to indicate that the shape may have rounded comers instead of sharp comers, curved edges instead of straight edges, one or more protrusions extending therefrom, is oblong, is the same as the disclosed shape, etc. Except as otherwise disclosed herein, any of the dimensions (e.g., length, width, thickness, radius of curvature, etc.) disclosed herein may refer to at least one of the maximum dimension, minimum dimension, or average dimension.

Claims

CLAIMSWhat is claimed is:

1. A structural fuse, comprising: a first attachment region; a second attachment region; and at least one yielding region extending between the first attachment region and the second attachment region, the at least one yielding region exhibiting: a length measured from the first attachment region to the second attachment region; a minimum width measured perpendicular to the length, the minimum width less than the length; and a thickness measured perpendicular to the length and the minimum width, the thickness less than the minimum width; and wherein a ratio of the length to the thickness (length / thickness) is about 8 or less.

2. The structural fuse of claim 1, wherein the length is about 5 cm about 50 cm.

3. The structural fuse of claim 1. wherein the minimum width is about 1 cm to about 10 cm.

4. The structural fuse of claim 1, wherein the thickness is about 0.5 cm to about 6.5 cm.

5. The structural fuse of claim 1. wherein the ratio of the length to the thickness is about 6 or less.

6. The structural fuse of claim 1, wherein the ratio of the length to the thickness is about 3 to about 6.

7. The structural fuse of claim 1, wherein a ratio of the minimum width to the thickness (minimum width / thickness) is about 1 to about 4.

8. The structural fuse of claim 1, wherein the at least one yielding region includes one or more comers at or near the first attachment region and / or the second attachment region that are rounded and exhibit an average radius of curvature.

9. The structural fuse of claim 8. wherein the average radius of curvature of the one or more comers is about 0.3 cm to about 6.5 cm.

10. The structural fuse of claim 8, wherein a ratio of the thickness to the average radius of curvature (thickness / average radius of curvature) is about 1 to about 2.

11. The structural fuse of claim 1, wherein the at least one yielding region includes a plurality of yielding regions, each of the plurality of yielding regions separated from each other by an elongated hole extending between the first attachment region and the second attachment region.

12. The structural fuse of claim 1, wherein the at least one yielding region does not include bolt holes configured to receive a bolt.

13. A structure, comprising: a first structural element; a second structural element spaced from the first structural element by a gap; and at least one structural fuse, the at least one structural fuse including: first attachment region attached to the first structural element; a second attachment region attached to the second structural element; and at least one yielding region extending between the first attachment region and the second attachment region, the at least one yielding region exhibiting: a length measured from the first attachment region to the second attachment region; a minimum width measured perpendicular to the length, the minimum width less than the length; and a thickness measured perpendicular to the length and the minimum width, the thickness less than the minimum width; and wherein a ratio of the length to the thickness (length / thickness) is about 8 or less; and wherein the structural fuse extending across the gap.

14. The structure of claim 13, wherein the first structural element and the second structural element each form a portion of a single, modified structural element, the single, modified structural element defining a slot extending through a majority of the single, modified structural element, the slot forming the gap between the first structural element and the second structural element.

15. The structure of claim 13. wherein the first structural element includes a column and the second structural element includes a beam.

16. The structure of claim 13, wherein the first structural element includes a beam and the second structural element includes a link beam.

17. The structure of claim 13, wherein the first structural element includes a w all and the second structural element includes a beam.

18. The structure of claim 13, wherein: the first structural element includes at least one of a wall or column; and the second structural element includes at least one of a floor or foundation.

19. The structure of claim 13, wherein the first attachment region is attached to the first structural element indirectly using at least one or more plates, the one or more plates attached to the first structural element.

20. The structure of claim 19, wherein the one or more plates includes a connecting beam having a first flange, a second flange, and a web extending between the first flange and the second flange.

21. The structure of claim 13, further comprising a third structural element; and wherein the at least one structural fuse includes a third attachment region attached to the third structural element and an additional yielding region between the second attachment region and the third attachment region; and wherein the yielding region is between the first attachment region and the third attachment region.

22. A method to retrofit a structure, the method comprising: forming a slot extending through a majority of a single, modified structural element to separate the single, modified structural into a first structural element and a second structural element; attaching a first attachment region of a structural fuse to the first structural element and a second attachment region of the structural fuse to the second structural element, the structural fuse extending across the slot, the structural fuse including at least one yielding region between the first attachment region and the second attachment region.

23. The method of claim 22, wherein the at least one yielding region extends between the first attachment region and the second attachment region, the at least one yielding region exhibiting: a length measured from the first attachment region to the second attachment region; a minimum width measured perpendicular to the length, the minimum width less than the length; and a thickness measured perpendicular to the length and the minimum width, the thickness less than the minimum width; and wherein a ratio of the length to the thickness (length / thickness) is about 8 or less.

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