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Inventors
Mueller, Lee W.
Application #
932181
Filed
Aug-17-2001
Published
Jul-13-2004
Current US Class
052/1
052/167.3
052/167.4
052/295
International Classes
E04B 001/98
Field of Search
52/167.3 52/167.4 52/167.1 52/1 52/295 52/296 52/297 52/300
Examiners
Friedman; Carl D.
Attorney, Agent or Firm
Knobbe, Martens, Olson & Bear, LLP
US Patent References
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Brace for reinforcin... |
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Holdown apparatu... |
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Friction device for... |
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Corrugated panel s... |
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Shear link energy... |
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Fastening device |
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Pre-assembled inte... |
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Method for strength... |
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Building structure... |
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Moment-resistant str... |
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| 6148583 |
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Reinforcing brace... |
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Method and appar... |
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Referenced by:
View Backward References
Other References
Fahim Sadek, Bijan Mohraz, Andrew W. Taylor, and Riley M. Chung, "Passive Energy Dissipation Devices for Seismic Applications", NISTIR 5923, U.S. Department of Commerce Technology Administration, Nov. 1996. PACO The Engineered Steel Company brochure. Light Beam System, Low Cost Steel Frame Housing, Light Beam Inc., Brochure, Jan. 1997. Light Beam System, LBN Shear Panel, Light Beam, Inc. Brochure, Jan. 1997. Ultra-Span Prefabricated Light Gauge Steel Truss System, MiTek, Brochure, 1996. CeeWal brochure Jul. 1999. Shear Max Panel, brochure, 1998. Zwall, Strength Where You Need It, brochure. ICBO Evaluation Service, Inc., Evaluation Report, Strong-Wall Shear Panels, Simpson Strong Tie Company, PFC-5485, Feb. 1,1999. Strong-Wall Shearwall, Simpson Strong Tie brochure, 1999. Strong-Wall Shearwall brochure, Simpson Strong Tie Connectors, Form PF-SW3 3/99 EXP 6/2000. Shear Max.TM. Panel, Product description brochure, 1998, 1 page. Shear-Max.TM. Panel, Installation Instructions, 1 page. Multi-Direction Insert brochure, Connection Specialties, Inc. SEMCO Metal Connectors, Southeastern Metals Manufacturing Company, Inc. Catalog, 1998.
Citation
Cite This Patent
More From Subclass 295
More From Class 052
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Abstract
Lateral motion devices are used in conjunction with shear assemblies to further dissipate shear forces on buildings. In one embodiment, the lateral motion device is interposed between the shear assembly and the upper portion of the wall to permit relative motion therebetween and to absorb and dissipate a portion of the shear forces through expansion and/or compression of spring members. In another embodiment, the lateral motion device is interposed between the foundation and the bottom of the shear assembly and in yet another embodiment, the lateral motion device is embedded in the foundation so as to be interposed between the anchor bolt and the foundation. The shear assembly can be either a panel assembly or an A-frame assembly.
Claims
What is claimed is:
1. A system for reducing shear and uplift forces between an upper portion and a foundation of a building, the assembly comprising:
a wall comprising a plurality of vertical studs wherein the wall includes an upper portion and a lower portion and wherein the upper portion of the wall is adjacent the upper portion of the building and the lower portion of the wall is adjacent the foundation of the building; and
a shear assembly that fits within a space defined by two adjacent studs of the wall, the upper portion of the wall, and the lower portion of the wall, such that the shear assembly couples the upper portion of the wall to the foundation wherein the shear assembly comprises:
an anchor assembly that anchors the shear assembly to the foundation of the building;
an attachment assembly that couples the shear assembly to the upper portion of the wall;
a first elongate member having an upper and a lower end interconnecting the anchor assembly and the attachment assembly wherein the upper end of the first elongate member is attached to a first lateral position on the attachment assembly and wherein the lower end of the first elongate member is attached to a second lateral position on the anchor assembly; and
a second elongate member having an upper and a lower end interconnecting the anchor assembly and the attachment assembly wherein the upper end of the second elongate member is attached to a third lateral position on the attachment assembly and wherein the lower end of the second elongate member is attached to a fourth lateral position on the anchor assembly and wherein the first and third lateral positions on the attachment assembly are located inward of the second and fourth lateral positions on the anchor assembly such that when a lateral shear force is exerted on the upper portion of the wall, one of the first and second elongate members is in compression and the other one of the first and second elongate members is in tension.
2. The system of claim 1, further comprising:
a third elongate member having an upper and a lower end interconnecting the anchor assembly and the attachment assembly wherein the upper end of the third elongate member is attached to the first lateral position on the attachment assembly and wherein the lower end of the third elongate member is attached to the second lateral position on the anchor assembly; and
a fourth elongate member having an upper and a lower end interconnecting the anchor assembly and the attachment assembly wherein the upper end of the second elongate member is attached to the third lateral position on the attachment assembly and wherein the lower end of the second elongate member is attached to the fourth lateral position on the anchor assembly and wherein the first and third lateral positions on the attachment assembly are located inward of the second and fourth lateral positions on the anchor assembly such that when a lateral shear force is exerted on the upper portion of the wall, one of the third and fourth elongate members is in compression and the other one of the third and fourth elongate members is in tension.
3. The system of claim 2, further comprising a lateral brace connected to the first and second elongate members at a point along the first and second elongate members located between the anchor assembly and the attachment assembly.
4. The system of claim 3, wherein the lateral brace is further connected with the third and fourth elongate members.
5. The system of claim 4, wherein the interconnection of the lateral brace with the elongate members reduces the unsupported length of the elongate members and provides increased resistance to buckling of the elongate members.
6. The system of claim 1, further comprising a lateral motion damping device that is mechanically coupled to at least one of the elongate members so as to permit limited relative movement of the elongate members with respect to the wall or the foundation so as reduce the amount of force that is transferred from the upper portion of the wall through the elongate members to the foundation.
7. The system of claim 6, wherein the lateral motion damping device comprises a housing that is interposed between the upper portion of the wall and the first and second elongate members so as to permit relative lateral movement between the upper portion of the wall and the first and second elongate members.
8. The system of claim 7, wherein the lateral motion damping device comprises a housing and at least one spring member mounted therein that expands and contracts to thereby absorb and dissipate at least a portion of the lateral shear forces exerted on the upper portion of the wall.
9. The system of claim 8, wherein the at least one spring member comprises a first and second spring that are mounted in the housing so as to be co-axial and so that a lateral shear force results in expansion of one spring and compression of the other.
10. The system of claim 9, wherein the at least one spring member further comprises a third and fourth spring that are mounted in the housing so as to be co-axial and so that a lateral shear force results in expansion of one spring and compression of the other.
11. The system of claim 6, wherein the lateral motion damping device is mechanically coupled to the bottom of at least one of the elongate members so as to reduce the amount of force that is transferred from the upper portion of the wall through the elongate member to the foundation.
12. The system of claim 11, wherein the lateral motion damping device comprises at least one compression disk that is interposed between the foundation and the bottom ends of the first and second elongate members such that shear forces result in compression of the at least one compression disk.
13. The system of claim 12, wherein the at least one compression disks is positioned within the anchor assembly.
14. The system of claim 6, wherein the anchor assembly comprises an anchor bolt that is mounted within the foundation and a hold down assembly that mechanically interconnects the first and second elongate members to the anchor bolts.
15. The system of claim 14, wherein the lateral motion damping device comprises a spring assembly that is mechanically interposed between the anchor bolt and the foundation such that shear forces travelling along the first and second elongate member are dissipated by the spring assembly.
16. The system of claim 15, wherein the spring assembly comprises:
a housing having an aperture through which the anchor bolt extends;
a first and a second compression plates positioned within the housing, wherein the first and second compression plates are mechanically coupled to the termination point of the anchor bolt;
a plurality of compression disks that are interposed between the first and second compression plates and wherein the anchor bolt is connected to both the first and second compression plates such that both tension and compressive forces being transmitted from the upper plate to the anchor bolt via the interconnecting member result in compression of the compression disks thereby dissipating at least a portion of the tension and compressive forces.
17. The system of claim 1, wherein the first and second elongate members comprise elongate rail members having a hollow rectangular cross section so as to resist buckling when compressed along the rail member's elongate direction.
18. A system for reducing the effects of shear forces on a building structure comprising:
a wall comprising a plurality of vertical studs wherein the wall includes an upper portion and a lower portion and wherein the upper portion of the wall is adjacent the upper portion of the building and the lower portion of the wall is adjacent a foundation of the building; and
a shear assembly that fits within a space defined by two adjacent studs of the wall, the upper portion of the wall, and the lower portion of the wall, such that the shear assembly couples the upper portion of the wall to the foundation wherein the shear assembly comprises:
a head assembly that couples the shear assembly to the upper portion of the wall;
an anchor assembly that couples the shear assembly to the foundation; and
an interconnecting structure that interconnects the head assembly to the anchor assembly so as to transfer forces between the upper portion of the wall and the foundation, the interconnecting structure comprising a first leg with first and second ends, and a second leg with first and second ends, wherein the first end of the first leg and the first end of the second leg are coupled to the head assembly so as to be separated by a first distance, and the second end of the first leg and the second end of the second leg are coupled to the anchor assembly so as to be separated by a second distance, wherein the first distance is less than the second distance such that the interconnecting structure resists relative movement between the head assembly and the anchor assembly by combinations of compression and tension of the first and second legs;
wherein at least a portion of a lateral shear force applied at the upper portion of the wall is transferred to the foundation through the head assembly and through the interconnecting structure such that one of the legs is in compression while the other leg is simultaneously in tension.
19. The system of claim 18, further comprising a lateral brace connected to the first and second elongate members at a point along the first and second elongate members located between the anchor assembly and the attachment assembly.
20. The system of claim 19, wherein the interconnection of the lateral brace with the elongate members reduces the unsupported length of the elongate members and provides increased resistance to buckling of the elongate members.
21. The system of claim 18, further comprising a lateral motion damping device that is mechanically coupled to at least one of the elongate members so as to permit limited relative movement of the elongate members with respect to the wall or the foundation so as reduce the amount of force that is transferred from the upper portion of the wall through the elongate members to the foundation.
22. The system of claim 21, wherein the lateral motion damping device is interposed between the upper portion of the wall and the first and second elongate members so as to permit relative lateral movement between the upper portion of the wall and the first and second elongate members.
23. The system of claim 22, wherein the lateral motion damping device comprises a housing and at least one spring member mounted therein that expands and contracts to thereby absorb and dissipate at least a portion of the lateral shear forces exerted on the upper portion of the wall.
24. The system of claim 23, wherein the at least one spring member comprises a first and second spring that are mounted in the housing so as to be co-axial and so that a lateral shear force results in expansion of one spring and compression of the other.
25. The system of claim 21, wherein the lateral motion damping device is mechanically coupled to the bottom of at least one of the elongate members so as to reduce the amount of force that is transferred from the upper portion of the wall through the elongate member to the foundation.
26. The system of claim 25, wherein the lateral motion damping device comprises at least one compression disk that is interposed between the foundation and the bottom end of the first and second elongate members such that shear forces result in compression of the at least one compression disk.
27. The system of claim 26, wherein the at least one compression disks are positioned within the anchor assembly.
28. The system of claim 21, wherein the anchor assembly comprises an anchor bolt that is mounted within the foundation and a hold down assembly that mechanically interconnects the first and second elongate members to the anchor bolts.
29. The system of claim 28, wherein the lateral motion damping device comprises a spring assembly that is mechanically interposed between the anchor bolt and the foundation such that shear forces travelling along the first and second elongate member result in at least a portion of the shear forces being dissipated by the spring assembly.
30. The system of claim 29, wherein the spring assembly comprises:
a housing having an aperture through which the anchor bolt extends;
a first and a second compression plates positioned within the housing, wherein the first and second compression plates are mechanically coupled to the termination point of the anchor bolt;
a plurality of compression disks that are interposed between the first and second compression plates and wherein the anchor bolt is connected to both the first and second compression plates such that both tension and compressive forces being transmitted from the upper plate to the anchor bolt via the interconnecting member result in compression of the compression disks thereby dissipating at least a portion of the tension and compressive forces.
31. The system of claim 18, wherein the first and second elongate members comprise elongate rail members having a hollow rectangular cross section so as to resist buckling when compressed along the rail member's elongate direction.
32. A system for reducing the effects of lateral and vertical shear forces on a building structure comprising:
a wall comprising a plurality of vertical studs and at least one upper horizontal plate interconnecting the plurality of vertical studs wherein the wall further comprises a lower portion wherein the upper horizontal plate is adjacent the upper portion of the building and the lower portion of the wall is adjacent a foundation of the building;
a shear assembly that fits within a space defined by two adjacent studs of the wall, the upper horizontal plate, and the lower portion of the wall, such that the shear assembly couples the upper portion of the wall to the foundation wherein the shear assembly comprises:
a head assembly that couples the shear assembly to the horizontal plate of the wall;
an anchor assembly that couples the shear assembly to the foundation;
an interconnecting member having a first end that is mechanically coupled to the head assembly and a second end that is mechanically coupled to the anchor assembly, wherein the interconnecting member transfers forces between the first and second ends; and
a lateral motion damping device that is mechanically coupled to the shear assembly so as to be interposed between the building structure and the shear assembly so as to permit limited relative movement between the shear assembly and the building structure such that at least a portion of the lateral shear forces exerted on the upper portion of the wall are dissipated by lateral damping device.
33. The system of claim 32, wherein the lateral motion damping device comprises a spring actuated device that is mechanically coupled to the shear assembly so as to be interposed between the building structure and the shear assembly so as to permit limited relative movement between the upper horizontal plate of the wall while still permitting shear forces to be transmitted to the foundation via the interconnecting member.
34. The system of claim 33, wherein the spring actuated member comprises a housing and a first and second spring that are mounted in the housing so as to be co-axial and so that a lateral shear force results in expansion of one spring and compression of the other.
35. The system of claim 34, wherein the housing is interposed between the interconnecting member and the upper horizontal plate of the wall.
36. The system of claim 35, wherein the housing is positioned within the head assembly.
37. The system of claim 32, wherein the lateral motion damping device is interposed between the interconnecting member and the foundation.
38. The system of claim 37, wherein the lateral motion damping device comprises at least one compression disk that is interposed between the foundation and the bottom end of the interconnecting member such that shear forces result in compression of the at least one compression disk.
39. The system of claim 38, wherein the at least one compression disk is positioned within the anchor assembly.
40. The system of claim 32, wherein the anchor assembly comprises an anchor bolt that is mounted within the foundation and a hold down assembly that mechanically interconnects to the interconnecting member to the anchor bolts.
41. The system of claim 40, wherein the lateral motion damping device comprises a spring assembly that is interposed between the anchor bolt and the foundation such that shear forces travelling along the interconnecting member result in expansion and contraction of the spring between the anchor member and the foundation.
42. The system of claim 41, wherein the anchor bolt includes a termination point that is positioned within a cavity in the foundation and the spring assembly is mechanically interposed between the termination point and the inner walls of the cavity in the foundation.
43. The system of claim 42, wherein the spring assembly comprises:
a housing having an aperture through which the anchor bolt extends;
a first and a second compression plates positioned within the housing, wherein the first and second compression plates are mechanically coupled to the termination point of the anchor bolt;
a plurality of compression disks that are interposed between the first and second compression plates and wherein the anchor bolt is connected to both the first and second compression plates such that both tension and compressive forces being transmitted from the upper plate to the anchor bolt via the interconnecting member result in compression of the compression disks thereby dissipating at least a portion of the tension and compressive forces.
44. The system of claim 43, wherein the anchor bolt is adapted to be movable within the foundation over a pre-selected range of movement to thereby facilitate dissipation of the tension and compressive forces by the plurality of compression disks.
45. The system of claim 32, wherein the interconnecting member comprises a first and second member that are attached to the head assembly so as to be separated by a first distance and are attached to the anchor assembly so as to be separated by a second distance which is greater than the first distance.
46. A method of reinforcing a building structure comprised of a wall mounted on a foundation having a plurality of vertical framing members and at least one upper horizontal plate interconnecting at least two of the plurality of vertical framing members, the method comprising:
mechanically coupling a shear assembly to the upper horizontal plate of the wall;
mechanically coupling the shear assembly to the foundation such that the shear assembly transmits lateral shear forces on the upper horizontal plate of the wall to the foundation so as to reduce the tendency of the upper portions of the vertical framing members to move laterally when exposed to shear forces; and
mechanically interposing a motion damper device between the shear assembly and the building structure such that a portion of the shear forces on the upper horizontal plate of the wall are dissipated by the motion damper device.
47. The method of claim 46, wherein mechanically coupling a shear assembly to the upper horizontal plate of the wall and mechanically coupling the shear assembly to the foundation comprises mounting a braced frame structure in the wall so as to be mechanically interposed between the upper horizontal plate and the foundation.
48. The method of claim 47, wherein mounting a braced frame structure in the wall comprises mounting an A-frame shear assembly in the wall so as to be mechanically coupled to the foundation and to the upper horizontal plate of the wall.
49. The method of claim 47, wherein mounting a braced frame structure in the wall comprises mounting a shear panel in the wall so as to be mechanically coupled to the foundation and to the upper horizontal plate of the wall.
50. The method of claim 47, wherein interposing a motion damper device between the shear assembly and the building structure comprises interposing a motion damper device between the upper horizontal plate and an upper portion of the shear assembly.
51. The method of claim 50, wherein mechanically interposing a motion damper device between the upper horizontal plate and the upper portion of the shear assembly comprises mechanically coupling a spring assembly between the upper horizontal plate and the upper portion of the shear assembly such that shear forces result in the spring assembly expanding and contracting a spring to thereby dissipate the portion of the shear forces.
52. The method of claim 47, wherein mechanically interposing a motion damper device between the shear assembly and the building structure comprises mechanically interposing a motion damper device between the shear assembly and the foundation of the building structure.
53. The method of claim 52, wherein mechanically interposing a motion damper device between the shear assembly and the foundation comprises mechanically interposing at least one compression disk between the bottom end of an interconnecting member of the shear assembly and the foundation such that shear forces result in compression of the compression disk.
54. The method of claim 52, wherein mechanically interposing a motion damper device between the shear assembly and the foundation comprises mechanically interposing a motion damper device between an anchor bolt of the shear assembly that is encased within the foundation and the foundation.
55. The method of claim 54, wherein the motion damper device comprises at least one compression disk that is mechanically coupled to the anchor bolt and to the foundation such that shear forces result in compression of the compression disk to thereby dissipate at least a portion of the shear forces.
56. A system for reducing the effects of shear forces on a building structure comprising:
a wall comprising a plurality of vertical studs wherein the wall includes an upper portion and a lower portion and wherein the upper portion of the wall is adjacent the upper portion of the building and the lower portion of the wall is adjacent a foundation of the building; and
a shear assembly that fits within a space defined by two adjacent studs of the wall, the upper portion of the wall, and the lower portion of the wall, such that the shear assembly couples the upper portion of the wall to the foundation wherein the shear assembly comprises:
an interconnecting structure having a first end and a second end, wherein the interconnecting structure transfers forces between the first end and the second end;
a head assembly that mechanically couples the upper portion of the wall to the first end of the interconnecting structure;
at least one spring member that is mechanically interposed between the first end of the interconnecting structure and the upper portion of the wall that permits limited relative movement between the upper portion of the wall and the first end of the interconnecting structure such that at least a portion of lateral shear forces exerted on the head assembly are dissipated by mechanical extension and retraction of the spring member; and
an anchor assembly that mechanically couples the second end of the interconnecting structure to the foundation.
57. The system of claim 56, wherein the interconnecting structure comprises a first and second member that are attached to the head assembly so as to be separated by a first distance and are attached to the anchor assembly so as to be separated by a second distance which is greater than the first distance.
58. The system of claim 56, wherein the at least one spring member comprises a housing and a first and second spring that are mounted in the housing so as to be co-axial and so that a lateral shear force results in expansion of one spring and compression of the other.
59. The system of claim 58, wherein the housing is interposed between the first end of the interconnecting member and the upper horizontal plate of the wall.
60. The system of claim 59, wherein the housing is positioned within the head assembly.
61. A shear assembly for reducing the effects of shear forces on a building structure that includes a wall attached to a foundation, the shear assembly comprising:
an interconnecting structure with a first end and a second end, wherein the interconnecting structure transfers forces between the first end and the second end;
a head assembly that mechanically couples an upper portion of the wall to the first end of the interconnecting structure; and
an anchor assembly that mechanically couples the second end of the interconnecting structure to the foundation, wherein the anchor assembly comprises at least one motion damping device that permits limited relative movement between the foundation and the second end of the interconnecting structure such that at least a portion of uplifting and downward compression forces exerted on the anchor assembly are dissipated by the at least one motion damping device.
62. The assembly of claim 61, wherein the anchor assembly comprises a plurality of compression disks that are mounted so as to be interposed between the interconnecting structure and the foundation such that shear forces on the interconnecting structure result in compression of the compression disks to thereby dissipate at least a portion of the shear forces.
63. The assembly of claim 62, wherein the interconnecting member includes at least one post and wherein the anchor assembly includes at least one bracket that receive the post.
64. The assembly of claim 63, wherein the compressible members are mounted within the bracket.
65. The assembly of claim 64, wherein the anchor assembly includes an anchor bolt that is mounted in the foundation, wherein the anchor bolt is attached to the bracket such that both compression forces and tension forces exerted on the anchor bolt by the interconnecting member result in compression of the compressible members thereby dissipating at least a portion of the forces.
66. The shear assembly of claim 61, wherein the interconnecting structure comprises a first and second member that are attached to the head assembly so as to be separated by a first distance and are attached to the anchor assembly so as to be separated by a second distance which is greater than the first distance.
67. A shear assembly for reducing shear and uplift forces between an upper portion of a wall and a foundation of a building, the assembly comprising:
a head assembly that is attached to the upper portion of the wall;
an interconnecting member that is mechanically coupled to the head assembly;
an anchor assembly that is coupled to the interconnecting member, wherein the anchor assembly includes at least one anchor bolt that is mounted in the foundation so as to be embedded therein; and
a motion damping device mechanically coupled to the embedded portion of the anchor bolt of the anchor assembly wherein forces exerted on the upper portion of the wall are transmitted to the foundation via the anchor assembly such that the motion damping device dissipates at least a portion of the forces transmitted to the foundation.
68. The assembly of claim 67, wherein the motion damping assembly comprises:
a housing having an aperture through with the anchor bolt extends;
a first and a second compression plates positioned within the housing, wherein the first and second compression plates are mechanically coupled to the termination point of the anchor bolt;
a plurality of compression disks that are interposed between the first and second compression plates and wherein the anchor bolt is connected to both the first and second compression plates such that both tension and compressive forces being transmitted from the upper plate to the anchor bolt via the interconnecting member result in compression of the compression disks thereby dissipating at least a portion of the tension and compressive forces.
69. The shear assembly of claim 68, wherein the anchor bolt is adapted to be movable within the foundation over a pre-selected range of movement to thereby facilitate dissipation of the tension and compressive forces by the plurality of compression disks.
70. The shear assembly of claim 68, wherein the interconnecting member comprises a first and second member that are attached to the head assembly so as to be separated by a first distance and are attached to the anchor assembly so as to be separated by a second distance which is greater than the first distance.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the construction industry and, in particular, concerns a method of providing lateral strengthening of wall structures using factory manufactured, field installed A-frame shear assembly with ductile attachment members.
2. Description of the Related Art
Low-rise, commercial, institutional and residential (single and multi-family) buildings comprise the majority of buildings in the United States. Within this group of buildings, by far the most prevalent type of structure is the light framed structure, specifically wood or cold-formed/light-gauge steel framing. In the typical light framed building structure, as in any other building structure, the basic structural design goals is to ensure the safe performance of the building under anticipated loading conditions. Safe performance may include, but is not limited to, one or more of the following performance objectives: operational/immediate occupancy performance, life safety performance and collapse prevention performance (FEMA-273 "NEHRP Guidelines for the Seismic Rehabilitation of Buildings," 1997).
The loads to be considered in design vary in the degree by which they can be reasonably (in a probabilistic sense) defined. Fundamentally though, there are two types of load to consider in design: gravity and lateral loads. Gravity loads, as the name implies, act vertically and they have one characteristic that makes them more deterministic than lateral loads-they can be controlled to some extent. Lateral loads (for example those induced by earthquakes and hurricane/tornado winds) are unpredictable in both occurrence and magnitude. In design for lateral load, the conventional philosophy has been to provide a lateral load resisting structural system that is strong enough to resist the maximum expected design event. In earthquake resistant design, this philosophy is further augmented by the additional requirement for inelastic deformation capability (ductility) of the lateral load resisting system. Inherent in this ductility requirement is the understanding that under the maximum design event, a building will undergo some amount of damage associated with the design performance objectives stated above.
In conventional light framed building construction, gravity and lateral load resistance is achieved essentially by a stick frame (studs, joists, rafter and trusses) for the gravity loads and sheathing attached to the stick frame for lateral loads. Loads are typically generated at different levels within the building and must be carried to the foundation via the combined action of the stick frame and the attached sheathing. This combined action implies that some elements of the gravity and lateral load systems will be common. As a result, failure of any one of these common elements under one loading condition (say lateral) can compromise the integrity of the entire system under the other condition.
Sheathed stick-framed walls that are designed to resist lateral loads are commonly referred to in the literature as shear walls or vertical diaphragms. The details of how a shear wall resists lateral load are quite complex. Generally though, the basic mechanism of resistance is achieved by a transfer of load from the point where they are generated into the frame, from the frame into the sheathing, from the sheathing back into the frame and from the frame into the foundation. Because of this load path, each component in the load path needs to have capacity of transferring the full load for a shear wall to work as expected. In other words, the performance of the shear wall is controlled by its weakest link. In earthquake resistant design, performance is attained by having the capacity to transfer loads at the foundation be higher than the capacity of the sheathing to frame attachment.
The sheathing materials commonly used in light frame shear wall construction typically include plywood, oriented strand board, fiberboard, gypsum wallboard/sheathing board, siding and sheet steel. The sheathing is typically attached to the frame with nails, staples or screws. In some cases, as may be the case with light gauge steel framing, sheet steel may be attached to the frame by clinching, welding or an adhesive. Additionally, in cold-formed steel construction lateral resistance may also be accomplished with flat-strap x-bracing. These generic systems, which are typically included in building codes, are not the only means of providing lateral resistance. In fact, other prefabricated systems are available for use as braced wall components. The primary benefits of these systems are improved performance due to the quality control associated with fabrication of the component and ease of installation in the field.
The aforementioned prefabricated systems, though more advanced than shear and x-braced walls, provide a response similar to that of the conventional field-built shear wall. That is, to develop a certain level of lateral resistance under the design event, these systems must undergo significant inelastic deformation (damage) which in turn results in damage to the contents and other non-structural components of the building. Furthermore, conventional shear walls and other prefabricated panel systems used in light framed buildings, may have to be comparatively large or strong to withstand the magnitude of lateral loads and/or deformations that are generated in design events or as limited by building codes. For example, most building codes limit the inelastic story drift or lateral displacement to between 2 inches and 2.5 inches for an 8-foot wall height in all types of buildings. To meet this limitation, the braced wall (shear wall, x-bracing or prefabricated system) must generally be ductile (ability to deform), strong and stiff. As the stiffness and strength of bracing components increase, the demands placed on other components of the structure also increases, thereby requiring larger members. It can be appreciated that multi-story buildings will be more susceptible to larger lateral forces/deformations often necessitating even larger lateral bracing structures. Increased spatial requirements for the lateral bracing system exacerbates the problem of a limited amount of space in walls of smaller lengths.
Hence, there is a need for a lateral bracing system that is easy to install, is comparatively small in size so that it can be readily installed in walls having short lengths, has the ability to dissipate energy without significant damage to the structures (and its components), has the ability to reduce the magnitude of deformations and forces induced in the building, improves life-safety of occupants and protects building functionality. To this end, there is a need for a prefabricated internal shear assembly with a mechanical lateral motion dampening device.
SUMMARY OF THE INVENTION
The aforementioned needs are satisfied by the A-frame shear assembly of the present invention which, in one aspect is comprised of a shear assembly for reducing shear and uplift forces between an upper portion of a wall and a foundation of a building, the assembly comprising an anchor assembly having a first and a second lateral end adapted to anchor the shear assembly to the foundation of the building; an attachment assembly adapted to be attached to the upper portion of the wall; a first elongate member having an upper and a lower end interconnecting the anchor assembly and the attachment assembly wherein the upper end of the first elongate member is attached to a first lateral position on the attachment assembly and wherein the lower end of the first elongate member is attached to a first lateral position on the anchor assembly; and a second elongate member having an upper and a lower end interconnecting the anchor assembly and the attachment assembly wherein the upper end of the second elongate member is attached to a third lateral position on the attachment assembly and wherein the lower end of the second elongate member is attached to a fourth lateral position on the anchor assembly and wherein the first and third lateral positions on the attachment assembly are located inward of the second and fourth lateral positions on the anchor assembly such that when a lateral shear force is exerted on the upper portion of the wall, one of the first and second elongate members is in compression and the other one of the first and second elongate members is in tension.
In another aspect of the invention the A-frame shear assembly is comprised of a shear assembly for reducing the effects of shear forces on a building structure that includes a wall attached to a foundation, the shear assembly comprising a head assembly that attaches to an upper portion of the wall; an anchor assembly that attaches to the foundation; an interconnecting structure that interconnects the head assembly to the anchor assembly so as to transfer forces between the upper portion of the wall and the foundation, the interconnecting structure comprising a first leg with first and second ends, and a second leg with first and second ends, wherein the first end of the first leg and the first end of the second leg are connected to the head assembly so as to be separated by a first distance, and the second end of the first leg and the second end of the second leg are connected to the anchor assembly so as to be separated by a second distance, wherein the first distance is less than the second distance such that the interconnecting structure resists relative movement between the head assembly and the anchor assembly by combinations of compression and tension of the first and second legs, wherein a lateral shear force applied at the upper portion of the wall is transferred to the foundation through the head assembly and through the interconnecting structure such that one of the legs is in compression while the other leg is simultaneously in tension.
A third aspect of the invention is comprised of a shear assembly for reducing the effects of lateral and vertical shear forces on a building structure that includes a wall having a plurality of vertical framing members and at least one upper horizontal plate interconnecting the plurality of vertical framing members wherein the wall is attached to a foundation, the assembly comprising a head assembly that attaches to the horizontal plate of the wall; an anchor assembly that attaches to the foundation; an interconnecting structure positioned between at least two of the vertical framing members of the wall wherein the interconnecting structure has a first end that is mechanically coupled to the head assembly and a second end that is mechanically coupled to the anchor assembly, wherein the interconnecting structure transfers forces between the first and second end; and a lateral motion damping device that is mechanically coupled to the shear assembly so as to be interposed between the building structure and the shear assembly so as to permit limited relative movement between the shear assembly and the building structure such that at least a portion of the lateral shear forces exerted on the upper portion of the wall are dissipated by lateral damping device.
A fourth aspect of the invention is comprised of a method of reinforcing a building structure comprised of a wall mounted on a foundation having a plurality of vertical framing members and at least one upper horizontal plate interconnecting at least two of the plurality of vertical framing members, the method comprising: mechanically coupling a shear assembly to the upper horizontal plate of the wall; mechanically coupling the shear assembly to the foundation such that the shear assembly transmits lateral shear forces on the upper horizontal plate of the wall to the foundation so as to reduce the tendency of the upper portions of the vertical framing members to move laterally when exposed to shear forces; and mechanically interposing a motion damper device between the shear assembly and the building structure such that a portion of the shear forces on the upper horizontal plate of the wall are dissipated by the motion damper device.
Yet another aspect of the invention is comprised of a shear assembly for reducing the effects of shear forces on a building structure that includes a wall attached to a foundation, the shear assembly comprising an interconnecting structure with a first end and a second end, wherein the interconnecting structure transfers forces between the first end and the second end; a head assembly that mechanically couples an upper portion of the wall to the first end of the interconnecting structure; and at least one spring member that is mechanically interposed between the first end of the interconnecting structure and the upper portion of the wall that permits limited relative movement between the upper portion of the wall and the first end of the interconnecting structure such that at least a portion of lateral shear forces exerted on the head assembly are dissipated by mechanical extension and retraction of the spring member; and an anchor assembly that mechanically couples the second end of the interconnecting structure to the foundation.
Another aspect of the invention is comprised of a shear assembly for reducing the effects of shear forces on a building structure that includes a wall attached to a foundation, the shear assembly comprising an interconnecting structure with a first end and a second end, wherein the interconnecting structure transfers forces between the first end and the second end; a head assembly that mechanically couples an upper portion of the wall to the first end of the interconnecting structure; and an anchor assembly that mechanically couples the second end of the interconnecting structure to the foundation, wherein the anchor assembly comprises at least one motion damping device that permits limited relative movement between the foundation and the second end of the interconnecting structure such that at least a portion of uplifting and downward compression forces exerted on the anchor assembly are dissipated by the spring member.
Another aspect of the invention is comprised of a shear assembly for reducing shear and uplift forces between an upper portion of a wall and a foundation of a building, the assembly comprising a head assembly that is attached to the upper portion of the wall; an interconnecting member that is mechanically coupled to the head assembly; an anchor assembly that is coupled to the interconnecting member, wherein the anchor assembly includes at least one anchor bolt that is mounted in the foundation so as to be embedded therein; and a motion damping device mechanically coupled to the embedded portion of the anchor bolt of the anchor assembly wherein forces exerted on the upper portion of the wall are transmitted to the foundation via the anchor assembly such that the motion damping device dissipates at least a portion of the forces transmitted to the foundation.
These and other objects and advantages of the present invention will become more fully apparent from the following description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B illustrate perspective views of A-frame shear assemblies installed in a wall frame;
FIG. 2 illustrates an exploded unassembled view of the A-frame shear assembly of FIG. 1;
FIG. 3A illustrates an A-frame rail of the A-frame shear assembly of FIG. 2;
FIG. 3B is a cross sectional view of the A-frame rail of FIG. 3A;
FIG. 3C illustrates a stiffener of the A-frame shear assembly of FIG. 2;
FIG. 3D illustrates a base rail of the A-frame shear assembly of FIG. 2;
FIG. 3E is a top view of a first shear plate of the A-frame shear assembly of FIG. 2;
FIG. 3F is a side view of the first shear plate of FIG. 3E;
FIG. 3G is a top view of a second shear plate of the A-frame shear assembly of FIG. 2;
FIG. 3H is a side view of the second shear plate of FIG. 3G;
FIG. 3I is an isometric view of a hold down bracket of the A-frame shear assembly of FIG. 2;
FIG. 3J is a top view of the hold down bracket of FIG. 3I;
FIG. 3K is a side view of the hold down bracket of FIG. 3I;
FIG. 3L is an isometric view of a hold down bolt bearing plate of the A-frame shear assembly of FIG. 2;
FIG. 4 is a perspective assembled view of one embodiment of a head assembly of the A-frame shear assembly, wherein the head assembly interconnects the A-frame to an upper portion of the wall in a substantially rigid manner;
FIG. 5 is an exploded unassembled view of the head assembly of FIG. 4;
FIG. 6 illustrates a gusset connector plate of the head assembly of FIG. 5;
FIG. 7 is a perspective assembled view of another embodiment of the head assembly of the A-frame shear assembly;
FIG. 8 is an exploded unassembled view of the head assembly of FIG. 7, wherein motion dampening is achieved in part by two motion damper coil springs arranged in a substantially coaxial manner;
FIG. 9A is an isometric view of a shock absorber slide actuator of the head assembly of FIG. 8;
FIG. 9B is an end view of the shock absorber slide actuator of FIG. 9A;
FIG. 9C is an isometric view of a plate connector of the head assembly of FIG. 8;
FIG. 9D is an isometric view of a motion damper slide of the head assembly of FIG. 8;
FIG. 9E is an end view of the motion damper slide of FIG. 9D;
FIG. 9F is an isometric view of a motion damper casing side of the head assembly of FIG. 8;
FIG. 9G is an end view of the motion damper casing side of FIG. 9F;
FIG. 9H is an isometric view of a motion damper casing end cap of the head assembly of FIG. 8;
FIG. 10 is a cutaway view of the head assembly of FIG. 9, illustrating positioning of the motion damper coil springs adapted to dampen lateral motion of upper portion of the wall relative to lower portion of the wall;
FIG. 11 illustrates an exploded unassembled view of another embodiment of the head assembly of the A-frame shear assembly, wherein the head assembly uses multiple motion damper coil springs to dampen lateral motion of top portion of the wall relative to bottom portion of the wall;
FIG. 12A is an isometric view of a motion damper slide of the head assembly of FIG. 11;
FIG. 12B is an end view of the motion damper slide of FIG. 12A;
FIG. 12C is an isometric view of a shock absorber slide actuator of the head assembly of FIG. 11;
FIG. 12D is an end view of the shock absorber slide actuator of FIG. 12C;
FIG. 12E is an isometric view of a motion damper casing side of the head assembly of FIG. 11;
FIG. 12F is an end view of the motion damper casing side of FIG. 12E;
FIG. 12G is an isometric view of a motion damper casing end cap of the head assembly of FIG. 11;
FIG. 12H illustrates one of the motion damper coil springs of the head assembly of FIG. 11;
FIG. 12I is a side view of the head assembly of FIG. 11;
FIG. 13 is a cutaway view of the head assembly of FIG. 11, illustrating positioning of the motion damper coil springs adapted to dampen lateral motion of upper portion of the wall relative to lower portion of the wall;
FIG. 14 illustrates a perspective view of another embodiment of the A-frame shear assembly that incorporates an anchor assembly that provides ductility;
FIG. 15 is an exploded unassembled view of the A-frame shear assembly of FIG. 14, illustrating the attachment of the anchor assembly to the A-frame;
FIG. 16A is illustrates a hold down bracket of the anchor assembly of FIG. 15;
FIG. 16B illustrates compression disks interposed between the legs of the A-frame shear assembly and the foundation;
FIG. 16C illustrates a side view of a compression plate of the anchor assembly of FIG. 15;
FIG. 16D illustrates a top view of the compression plate of FIG. 16C;
FIG. 16E illustrates a side view of the compression disk of the anchor assembly of FIG. 15;
FIG. 16F illustrates a top view of the compression disk of FIG. 16E;
FIG. 16G illustrates a side sectional view of the anchor assembly of FIG. 15;
FIG. 16H illustrates an end sectional view of the anchor assembly of FIG. 15 when the compression disks are at rest;
FIG. 16I illustrates the anchor assembly of FIG. 16H when the compression disks are compressed due to a downward compression force applied on one of the legs of the A-frame;
FIG. 16J illustrates the anchor assembly of FIG. 16H when the compression disks are compressed due to an upward tension force applied on one of the legs of the A-frame;
FIG. 17A illustrates a perspective view of a head assembly of the A-frame shear assembly of FIG. 14, wherein the head assembly is adapted to permit limited motion of the anchor assembly of FIG. 15;
FIG. 17B illustrates shear transfer plates of the head assembly of FIG. 17A;
FIG. 18 illustrates another embodiment of the A-frame shear assembly that has a ductile anchor assembly with spring members cast within the foundation;
FIG. 19 illustrates a sectional view of the ductile anchor assembly of FIG. 18;
FIGS. 20A and 20B illustrate the use of ductile hold down anchors on a fiberglass or plastic panel;
FIGS. 21A and 21B illustrate the use of ductile hold down anchors on a steel panel;
FIGS. 22A and 22B illustrate the use of ductile hold down anchors on a tube steel panel;
FIGS. 23A and 23B illustrate the use of the ductile hold down anchors and the above-ground ductile hold down assembly on a Cee channel panel; and
FIGS. 24A and 24B illustrate the use of a damper assembly on a generic shear panel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will now be made to the drawings wherein like numerals refer to like parts throughout.
FIGS. 1A and 1B illustrate a perspective view of an A-frame shear assembly 100 installed in a wall frame 140. The wall frame 140 comprises a plurality of studs 144 interconnected by a top plate 142 and a bottom plate 143. The A-frame shear assembly 100 is installed between two adjacent studs 144, and interconnects the top plate 142 to a foundation 150 in manners described below. The A-frame shear assembly 100 comprises a head assembly 110 interconnected to an anchor assembly 130 by a rail assembly 120 to provide structural advantages described below. As is illustrated in FIGS. 1A and 1B, the head assembly 110 can either be a head assembly 110 that is rigidly attached to the upper portion of the wall or it can be a flexible head assembly 110 that permits relative movement between the upper portion of the wall and the shear assembly 100.
The description hereinafter is generally organized such that the A-frame rail assembly 120 and a substantially rigid anchor assembly are described first. Various embodiments of the head assembly 110 are then described, including the A-figure assembly that is rigidly attached to the upper portion of the wall and the A-frame assembly that is attached to the upper portion of the wall in a motion damping manner. Then, various embodiments of the anchor assemblies that provide ductility between the rail assembly 120 and the foundation 150 are described. In the description hereinafter, references are made to attachments of the A-frame shear assembly (or portion of the A-frame shear frame assembly) to the top plate 142. It will be appreciated and understood that, for the description purpose, the top plate 142 is considered to be an upper portion of the wall which is interconnected to other structures, such as a roof. Lastly, various embodiments of shear panels, other than the A-frame, are illustrated with motion damping members incorporated therein.
FIG. 2 illustrates one embodiment of an exploded unassembled view of the A-frame shear assembly 100 interposed between two adjacent studs 144 that can be connected to the top plate 142 in the manner illustrated in either FIG. 1A or 1B. The A-frame shear assembly 100 comprises a first rail 201, a second rail 202, a third rail 203, and a fourth rail 204 that are interconnected in manners described below. The first rail 201 is substantially same as the fourth rail 204, and the second rail 202 is substantially same as the third rail. The first and fourth rails 201, 204 differ from the second |