US20090151273A1

US20090151273A1 - High-strength shear wall sheathing with pre-formed fastener holes

Info

Publication number: US20090151273A1
Application number: US12/315,823
Authority: US
Inventors: Erich Jason Axsom
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-12-12
Filing date: 2008-12-05
Publication date: 2009-06-18

Abstract

A sheet of high-strength shear wall sheathing with preformed fastener holes (10) is disclosed as a steel sheet (12) with uniformly spaced fastener holes (14) dispersed along the boundary of the sheet. Such a sheet can readily be handled and quickly attached to the framework of buildings for the purpose of bracing wall structures in a single wall sheathing procedure.

Description

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING OR PROGRAM

Not Applicable

BACKGROUND

1. Field of Invention
The invention relates to buildings and, more particularly, to an improved shear wall sheathing product for use in framed residential and commercial buildings.
2. Description of Prior Art
Since the time of the Industrial Revolution, framed building structures have a played a vital role in fulfilling the housing needs of an expanding U.S. population. It was in the 1830's that the first “Balloon Framed” structure was developed. Coupled with the means to mass produce nails, this new form of framing enabled builders to construct a home far more rapidly and for less money than the previous method of building which was referred to as “Post & Beam” or “Post-Frame” construction. A short time later, around the 1850's, “Balloon Framing” evolved into “Platform Framing.” And to this day, well over a century later, the platform framing method is still employed as the best means for constructing homes in terms of both time and money savings.
Bracing these new light framed structures for stability was recognized as an essential element necessary for the safety of the occupants. Transient horizontal forces acting on these structures like those generated by wind and earthquakes were dealt with in much the same way until the 1960's. That is, between the 1830's and late 1950's, both the balloon framed structures as well as the platform framed structures (hereinafter referred to as “light framed structures”) were braced with 1×6 sheathing boards fastened with two nails to each stud. Later, around the 1960's, the 1×6 sheathing boards were replaced with sheets of plywood. Basically, builders recognized that a single sheet of plywood could replace 16-1×6's and required half the amount of nails to provide at least the same level of strength and rigidity. This has been verified by many tests proving sheathed vertical diaphragms, also known as shear walls in light framed construction, can absorb a great deal of energy before failure making them very ductile and reliable. Plywood and its derivatives, such as oriented strand board, are still employed today as the best means for bracing homes and other low-rise light framed structures in terms of both time and money savings. However, plywood and its derivatives lack the necessary qualities needed to address changing modern light frame buildings and stricter modern building code requirements.
Shear walls, in modern light framed structures, are a complex assembly comprised of wall framework such as wall studs, sheathing panels such as plywood, and fasteners such as nails or screws. Since the 1960's, when plywood began to replace 1×6 sheathing boards as the preferred method of bracing light frame structures, there have been a plethora of installation problems that have significantly diminished the overall strength and rigidity of plywood sheathed shear walls. For example, Fasteners (usually nails but sometimes screws) are routinely overdriven through the plywood, spaced too far apart, spaced too close together, or may not penetrate and properly embed themselves into the underlying framework. In many cases it's very common for two or more of these installation problems to exist simultaneously, which further compounds the problem resulting in a significantly weaker shear wall system. When fasteners are overdriven through the plywood or spaced too far apart they tend to pull through the plywood sheathing before their intended in-plane shear capacity can be reached. When fasteners are spaced too close together they tend to split the underlying framework and pry loose from the underlying framework before their intended in-plane shear capacity can be reached. And, when fasteners penetrate the plywood sheathing without penetrating and embedding themselves firmly into the underlying framework they essentially provide no in-plane shear strength and no rigidity to the shear wall system.
Another problem with plywood used as shear wall bracing is that it's limited to applications where it's height can not exceed 3.5 times it's width (hereinafter referred to as “shear wall aspect ratio”) as mandated by modern building codes. Otherwise, per modern building codes, shear walls braced with plywood exceeding this 3.5 to 1 aspect ratio have absolutely no capacity. Unfortunately, it's very common today in light framed structures to exceed this ratio for walls with large openings or closely spaced openings. For example, this occurs in almost all residential construction of garage walls with a car door opening. An expensive solution to this problem has been to provide cantilevered steel columns as bracing in lieu of plywood sheathed shear walls. Per modern building codes, these cantilevered steel columns are required to be designed for a much higher earthquake force than required for a plywood sheathed shear wall, are difficult to properly install and by comparison are much more expensive to install in terms of material and labor cost than plywood sheathed shear walls.

OBJECTS AND ADVANTAGES

Accordingly, it is an object of the present invention to provide a high-strength shear wall sheathing with preformed holes that is easy to handle and installs quickly.
It is also an object of the invention to provide a high-strength shear wall sheathing with pre-formed holes that has sufficient strength and rigidity to adequately resist in-plane shear loads resulting from wind and earthquake forces.
It is a further object of the invention to a high-strength shear wall sheathing with pre-formed holes that will eliminate overdriving fasteners, spacing fasteners too far apart or too close together, and prevent fasteners from missing underlying framework thereby significantly improving in-plane shear wall capacity.
It is still further an object of the invention to provide a high-strength shear wall sheathing with pre-formed holes that can be used in applications where the shear wall aspect ratio exceeds 3.5 to 1.

SUMMARY OF INVENTION

In accordance with the present invention a sheet of high-strength shear wall sheathing with pre-formed fastener holes is comprised of a thin sheet of steel with uniformly spaced fastener holes dispersed along the boundary of each sheet. Such a sheet of high-strength shear wall sheathing can readily be handled and quickly attached to the framework of a building for the purpose of bracing the wall structure in a single wall sheathing procedure.

DRAWING FIGURES

FIG. 1 shows an isometric view of the present invention which consists of a sheet of high-strength shear wall sheathing with pre-formed fastener holes dispersed long the boundary of the sheet.

FIG. 2A shows a partial broken away elevation view of a sheet of high-strength shear wall sheathing of FIG. 1 with a single line of pre-formed fastener holes dispersed along the boundary of the sheet.

FIG. 2B shows a partial broken away elevation view of a sheet of high-strength shear wall sheathing of FIG. 1 with two lines of pre-formed fastener holes dispersed along the boundary of the sheet.

FIG. 3A shows a partial broken away cross-sectional view of a sheet of high-strength shear wall sheathing of FIG. 2A with a single line of pre-formed fastener holes dispersed along the boundary of the sheet.

FIG. 3B shows a partial broken away cross-sectional view of a sheet of high-strength shear wall sheathing of FIG. 2A with a single line of pre-formed fastener holes dispersed along the boundary of the sheet where the boundary is bent 180 degrees onto itself.

FIG. 4 shows a partial broken away cross-sectional view of a wall stud framework employing two separate sheets of high-strength shear wall sheathing arranged side by side.

REFERENCE NUMERALS IN DRAWINGS

- 10 high-strength shear wall sheathing with pre-formed fastener holes
- 12 thin sheet of steel
- 14 pre-formed fastener holes
- 20 wall studs (forming a part of the wall framework)
- 22 fasteners (nails or screws)

DETAILED DESCRIPTION

Description

FIG. 1 Through FIG. 3—Preferred Embodiment

A preferred embodiment of high-strength shear wall sheathing with pre-formed fastener holes of the present invention is illustrated in FIG. 1 (an isometric view), FIG. 2 (two partial broken away elevation views) and FIG. 3 (two partial broken away cross-sectional views) which comprises a thin sheet of steel 12 with pre-formed fastener holes 14 dispersed along the boundary of the sheet.
Steel sheet 12 is generally manufactured in a rectangular shape of 4 feet wide by 8 feet long, but can be smaller or larger in extents. Steel sheet 12 is typically manufactured in a thickness range between 0.006 inches and 0.249 inches, but can be thicker. Steel sheet 12 should posses a minimum tensile strength of 20,000 pounds per square inch since a lower tensile strength would result in a substantially thicker sheet. Furthermore, while the preferred embodiment has been directed to a steel sheet, other metal sheets may also be used such as aluminum. Other Thin high strength materials, such as plastic for example, may be used as well.
Pre-formed fastener holes 14 are typically dispersed along the boundary of sheet steel 12 at a uniform spacing at least ½ inch apart and are at least ¼ inch from the edge of the sheet. Pre-formed fastener holes 14 may be dispersed along the boundary of steel sheet 12 in a single line as shown in FIG. 2A, FIG. 3A and FIG. 3B or may they be dispersed in multiple lines of two or more as shown in FIG. 2B and FIG. 3B if greater in-plane shear strength and rigidity is desired. Pre-formed fastener holes 14 have a diameter approximately equal to the size of the fasteners 22 used to attach the sheet of high-strength shear wall sheathing 10 to wall stud 20. For example, fasteners 22 (nails or screws) can range in diameter from 0.099 to 0.190 inches but may be smaller or larger.
Where increased in-plane shear strength and rigidity is desired, the boundary of steel sheet 12 may be bent 180 degrees onto itself as shown in FIG. 3B. The advantage of increasing the thickness of steel sheet 12 along the boundary is two fold: in-plane shear strength and rigidity of high-strength shear wall sheathing 10 is significantly increased due to a stiffening effect and the bearing area between fasteners 22 and steel sheet 12 is significantly increased which significantly increases the shear strength of fasteners 22.
High-strength shear wall sheathing with pre-formed fastener holes 10 could be made employing automated processes. For example, sheet steel 12 could be manufactured by automated machinery well known in the industry. Sheet steel 12 could then be shipped to a steel fabrication facility, also well known in the industry, to cut each steel sheet 12 to a specific size. Next, the sheet steel 12 will have pre-formed holes 14 punched or drilled along the boundary of the sheet at a specific size and spacing. The resulting high-strength shear wall sheathing with pre-formed fastener holes 10 may then be hand stacked onto a pallet for shipping to the construction site or to a staging warehouse for temporary storage.

ADVANTAGES

From the description above, it's apparent that the present sheet of high-strength shear wall sheathing with preformed holes has the distinct advantage of being easily handled and quickly installed to the framework of a building for the purpose of bracing wall structures in a single sheathing procedure. It's further apparent that the sheet of high-strength shear wall sheathing with preformed holes has the following advantages:

- High-strength shear wall sheathing with preformed holes has sufficient strength and rigidity to adequately resist in-plane shear loads resulting from wind and earthquake forces.
- High-strength shear wall sheathing with preformed holes eliminates overdriving fasteners, spacing fasteners too far apart or too close together, and prevents fasteners from missing underlying framework to thereby significantly improve in-plane shear wall capacity.
- High-strength shear wall sheathing with preformed holes can be used in applications where shear wall aspect ratio's exceed 3.5 to 1

OPERATION

FIG. 4

FIG. 4 illustrates a sheet of high-strength shear wall sheathing with preformed holes 10 attached to wall studs 20 of a typical light framed building structure. The sheet of high-strength shear wall sheathing with preformed holes 10 may be attached to wall studs 20 by fasteners 22 comprising either nails or screws. Once the sheet of high-strength shear wall sheathing with preformed holes 10 is attached to the light framed building structure, such as wall studs 20, high-strength shear wall sheathing 10 will assist the building framework in resisting in-plane or shear loads that are exerted on the building structure resulting from environmental conditions such as wind and earthquakes.
The pre-formed holes 14 in metal sheet 12 provides several distinct advantages. For example, by spacing pre-formed holes 14 at a uniform distance apart in steel sheet 12 they serve as a template to insure fasteners 22 are installed accurately at a uniform spacing. Stresses due to wind and earthquake forces on metal sheet 12 and fasteners 22 are thereby evenly distributed resulting in a significantly increased in-plane shear capacity for high-strength shear wall sheathing 10. Additionally, pre-formed holes 14 in metal sheet 12 also allow the installer to clearly see the underlying framework prior to installing fasteners 22. As a result, fasteners 22 are prevented from missing the underlying framework thereby significantly increasing the in-plane shear capacity for high-strength shear wall sheathing 10.
Steel sheet 12 also provides several advantages. Unlike plywood, fasteners 22 cannot be overdriven through steel sheet 12. As a result, fasteners 22 are prevented from pulling through metal sheet 12 thereby significantly increasing the in-plane shear capacity for high-strength shear wall sheathing 10. Additionally, steel sheet 12 can be used in applications where the shear wall aspect ratio exceeds 3.5 to 1. That's because, unlike plywood, steel sheet 12 can absorb the increased stresses at the corners of the sheet caused by high shear wall aspect ratio effects without tearing. This is due to the inherent strength and ductility of steel sheet 12 thereby allowing a sheet of high-strength shear wall sheathing 10 to be used where plywood would be unacceptable.

CONCLUSION, RAMIFICATIONS, AND SCOPE

Accordingly, the reader will see that the sheet of high-strength shear wall sheathing with preformed holes has the distinct advantage of being easily handled and quickly installed to the framework of a building for the purpose of bracing wall structures in a single sheathing procedure. Furthermore, it's apparent that the sheet of high-strength shear wall sheathing with preformed holes has the following advantages in that:

- High-strength shear wall sheathing with preformed holes has sufficient strength and rigidity to adequately resist in-plane shear loads resulting from wind and earthquake forces.
- High-strength shear wall sheathing with preformed holes eliminates overdriving fasteners, spacing fasteners too far apart or too close together, and prevents fasteners from missing underlying framework to thereby significantly improve in-plane shear wall capacity.
- High-strength shear wall sheathing with preformed holes can be used in applications where shear wall aspect ratios exceed 3.5 to 1.

Although the description above contains many specifics, these should not be construed as limiting the scope of the invention but merely providing an illustration of the presently preferred embodiments of this invention. It should be understood that various changes and modifications obvious to one skilled in the art to which the invention pertains are deemed to lie within the spirit and scope of the invention as set forth in the following claims.

Claims

1. A building shear wall structure for accommodating in-plane or shear loads imposed on the wall structure comprising:

a plurality of framing studs forming part of the building;

a plurality of high-strength shear wall sheathing sheets, each sheet of high-strength shear wall sheathing comprising only one thin sheet of high strength material with pre-formed holes dispersed along the boundary of the sheet; and

securing means for attaching the sheets of high-strength shear wall sheathing to the framing studs such that the thin sheet of high strength material sits directly against the framing studs, the thin sheet of high strength material having properties at least as great as a steel sheet having a thickness within the range of 0.006 and 0.249 inches and having a tensile strength of at least 20000 pounds per square inch, the thin sheet of high strength material being capable of resisting anticipated in-plane or shear loads imposed on the shear wall structure due to environmental conditions such as wind and earthquakes.

2. The sheet of high-strength shear wall sheathing of claim 1 wherein the thin sheet of high strength material is a metal.

3. The sheet of high-strength shear wall sheathing of claim 2 wherein the metal is steel.

4. The sheet of high-strength shear wall sheathing of claim 3 wherein the steel sheet is bent 180 degrees onto itself along the boundary of the sheet.

5. The sheet of high-strength shear wall sheathing of claim 2 wherein the metal is aluminum.

6. The sheet of high-strength shear wall sheathing of claim 1 wherein the thin sheet of high strength material is a plastic.

7. The pre-formed holes of claim 1 wherein the holes are dispersed along the boundary of the sheet in a single line.

8. The pre-formed holes of claim 1 wherein the holes are dispersed along the boundary of the sheet in two lines.

9. The pre-formed holes of claim 1 wherein the holes are dispersed along the boundary of the sheet in three lines.

10. The sheet of high-strength shear wall sheathing of claim 3 wherein the steel sheet has a thickness within the range of 0.006 and 0.249 inches.

11. The sheet of high-strength shear wall sheathing of claim 5 wherein the aluminum sheet has a thickness within the range of 0.006 and 0.249 inches.

12. The shear wall structure of claim 1 wherein the securing means comprises screws.

13. The shear wall structure of claim 1 wherein the securing means comprises nails.

14. A building shear wall structure for accommodating in-plane or shear loads imposed on the wall structure comprising:

a plurality of framing studs forming part of the building;

a plurality of high-strength shear wall sheathing sheets, each sheet of high-strength shear wall sheathing comprising only one thin steel sheet having a thickness within the range of 0.006 and 0.249 inches and having a tensile strength of at least 20000 pounds per square inch; and

a plurality of fasteners extending through the high-strength shear wall sheathing and into the framing studs so that the steel sheets sit flush against the framing studs, each steel sheet being capable of resisting in-plane or shear loads anticipated to be imposed on the shear wall due to wind and earthquakes.

15. The shear wall structure of claim 14 wherein the fasteners are screws.

16. The shear wall structure of claim 14 wherein the fasteners are nails.

17. A building shear wall structure for accommodating in-plane or shear loads imposed on the wall structure comprising:

a plurality of framing studs forming part of the building;

a plurality of high-strength shear wall sheathing sheets, each sheet of high-strength shear wall sheathing comprising only one thin aluminum sheet having a thickness within the range of 0.006 and 0.249 inches and having a tensile strength of at least 20000 pounds per square inch; and

a plurality of fasteners extending through the high-strength shear wall sheathing and into the framing studs so that the aluminum sheets sit flush against the framing studs, each aluminum sheet being capable of resisting in-plane or shear loads anticipated to be imposed on the shear wall due to wind and earthquakes.

18. The shear wall structure of claim 17 wherein the fasteners are screws.

19. The shear wall structure of claim 17 wherein the fasteners are nails.