US20030136075A1

US20030136075A1 - Construction brace for use against seismic and high wind conditions

Info

Publication number: US20030136075A1
Application number: US10/346,602
Authority: US
Inventors: Charles Brackett
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-01-18
Filing date: 2003-01-18
Publication date: 2003-07-24

Abstract

Wood framed walls of buildings are strengthened against destructive wind and seismic forces by angled brackets attached to vertical studs and anchored to the building foundation. The bracket can be attached to a foundation structure of the building and to a stud and floor plate. The bracket can also be attached to a stud and ceiling plate. The foundation structure may be concrete or other floor joist or the like. The angled brackets are normally used in a system that attaches a bracket at top and bottom of studs at approximately every fourth or fifth stud along all load-bearing walls. In an alternate embodiment, an elongated steel rod can be attached to the foundation and directly to a roof truss and ceiling plate. The described brackets can be installed during initial construction of a structure or retrofit into existing structures.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is based upon and gains priority from U.S. Provisional Patent Application Serial No. 60/349,470 filed Jan. 18, 2002 by the inventor herein and entitled “Construction Brace for use Against Seismic and High Wind Conditions,” the specification of which is incorporated herein by reference.[0001]

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to wood frame building structures, and more particularly to structures exposed to extreme wind and/or seismic conditions where building codes dictate that these structures be protected against structural failure and/or to save lives of occupants. In particular, the present invention relates to a hold-down system for anchoring the structure of a wood frame building to resist uplift forces encountered during a high wind or seismic situation. The present invention also relates to a system of brackets that provides additional reinforcements for an existing structure.

2. Background of the Prior Art

It is well known what high winds can do to a building, particularly to a wood frame construction low-rise structure. Generally, uplift forces tending to lift the roof off the structure or the entire structure off its foundation cause much of the damage sustained by the building.

Wood structures predominate in residential and light commercial construction, and when wood framing is employed, the structure must be protected from upward, shear and overturning loads developed by either wind or seismic activity, which differs with geographical location and is enforced by different building codes for these areas For example, the Bahamas and Florida, including the Florida Keys are situated in the pathway of the yearly Caribbean hurricane travel course and as such, encounter hurricanes and/or tornadoes from time to time.

In the case of upward loads, the building is generally tied to the foundation using a variety of steel connectors that tie the bottom plate to the foundation, wall studs to bottom plates, top plate to wall studs, floors to walls, and roof to walls. Typically, for uplift, connectors are attached to every stud (16″ O.C.), or at least every other stud (32″ O.C.). Shear and overturning loads are resisted by a combination of heavy-duty steel connectors, (either bolted to, or embedded in, the foundation, and nailed or bolted to the wood frame), and an approved structural sheathing material nailed directly to the exterior of the structure is used to create what is referred to as a “shear wall”. The size and number of such steel connectors vary depending on the severity of the wind and/or seismic conditions expected in the locality of the building, and the building's geometry.

In the current method used in the United States, such connectors are installed during the foundation and framing stages of construction. Laborers hired by the framing contractor generally install the connectors and sheathing. Correct size, location and number of fasteners (nails or bolts), are critical to the required load. Commonly, these laborers are inexperienced which frequently results in improper or inadequate installation. In all structures, the locations of most connectors mandate their installation during the framing stage due to related building components being placed at the same time. This process slows the foundation and framing stages of construction, which in turn increases labor costs. In addition, existing structures without having appropriate connectors in place are at risk of destruction should a hurricane or earthquake occur.

From the foregoing, it is apparent that there is a critical need for a structural tie-down system that provides for uplift, shear and overturning loads that is cost effective and easy to install an that can be installed after the foundation and framing stages of the building is complete.

SUMMARY OF THE INVENTION

The present invention provides a solution to the above problem by reinforcing and anchoring the structure to the ground, wherein a hold down force is applied to the wall studs to counter the uplift and horizontal forces generated by high winds. The present invention can be incorporated during initial construction of the structure or retrofit into preexisting structures.

It is an object of the present invention to provide an anchor bracket system for a structure of a wood frame building that reinforces the structure against damage in a high wind situation, such as a hurricane.

It is a further object of the present invention to enable installation of an anchor bracket system after the foundation is set, without prior embedding anchor bolts. A related object is to enable installation of an anchor bracket system after the roof, wall framing and exterior sheathing are in place.

It is another object of the present invention to provide an anchor bracket system for a frame construction building that provides a downward force around the periphery of the structure, thereby to better resist any upward lift imparted to the walls and roof by high winds. It is still another object of the present invention to provide an anchor bracket system for a low-rise, wood frame building that can be easily installed in preexisting structures. A related object is to enable increased uplift resistance in preexisting structures with minimum invasion of wall members. A further related object is to increase value in structures existing in high wind and seismic zones.

It is another object of the present invention to provide an anchor bracket system for a low-rise, wood frame building that provides reinforcement to the walls and roof structure, thereby providing greater resistance to damage during high wind conditions. A related object is to increase public safety in structures existing in high wind and seismic zones. A further related object is to allow wall studs to serve as tie-down elements by reinforcing the connection to the foundation and roof.

It is a further object of the present invention to eliminate the need for hurricane clips and straps to be installed at top and bottom plates in the construction of a wood frame construction building.

It is yet another object of the present invention to enable cost effective construction of wood frame structures while meeting all Building Code requirements. A related object is to provide an anchor bracket system for a low-rise building that complies with the recommendation of all major building codes.

This invention relates to a novel method of bracing a wood framed building, e.g., a residential dwelling, having a structure including a foundation upon which rests a plurality of parallel vertical studs separating horizontal floor plates from horizontal ceiling plates. The structure is reinforced against the destructive forces of the atmosphere and of seismic origin by high strength brackets attached at the top and bottom of selected vertical studs between floor plates and ceiling plates, at much greater spacing than 32″ O.C. In an alternate embodiment, a vertical connection is made between such horizontal floor plate and horizontal ceiling plate, the attached roof trusses, and the concrete foundation. The bracket is connected to the structure by way of lag bolts and to anchors embedded in the foundation. Additionally, attachment can be made to a beam, floor system or roof truss or girder member.

The bracket disclosed herein offers more body, more strength and more durability to the purchasing public. Such anchor brackets may be made from a graduated increase in steel gauges in a variety of sizes and connectors to fit many framing applications and strength requirements. Such anchor brackets create a solid attachment between the foundation and wall stud or between the ceiling top plate and wall stud. This simple invention enables a family of anchor brackets that can be mass-produced and sold for a reasonable price that, in fact, can be made or put in place by any skilled or semi-skilled person.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features, aspects, and advantages of the present invention are considered in more detail, in relation to the following description of embodiments thereof shown in the accompanying drawings, in which: [0019]
FIGS. 1[0020] a, 1 b, and 1 c show an illustration of three embodiments of an anchor brace according to the present invention;
FIGS. 2[0021] a and 2 b show an embodiment of the present invention as used in a bottom wall connector embodiment;
FIG. 3 is a cross sectional view of a method of embedding a threaded rod in a foundation according to the present invention; [0022]
FIGS. 4[0023] a and 4 b show an embodiment of the present invention as used in a top wall connector embodiment;
FIGS. 5[0024] a and 5 b show an alternate embodiment of the present invention utilizing a threaded rod tie-down; and
FIG. 6 is an elevational view of a typical load bearing wall section employing the present invention.[0025]

DETAILED DESCRIPTION OF THE INVENTION

The invention summarized above and defined by the enumerated claims may be better understood by referring to the following description, which should be read in conjunction with the accompanying drawings in which like reference numbers are used for like parts. This description of an embodiment, set out below to enable one to build and use an implementation of the invention, is not intended to limit the enumerated claims, but to serve as a particular example thereof. Those skilled in the art should appreciate that they may readily use the conception and specific embodiments disclosed as a basis for modifying or designing other methods and systems for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent assemblies do not depart from the spirit and scope of the invention in its broadest form. [0026]
Referring to FIG. 1[0027] a, an angled brace 10 is illustrated, having a facing portion 13 and an L-shaped extension 16. Such brace 10 should be manufactured of A36 steel, or equivalent, approximately ⅛-inch thick, measuring approximately 8-inches×2-inches on the facing portion 13. The L-shaped extension 16 should extend at least 2-inches from an end of brace 10, within which a single hole approximately ⅛-inch in diameter is formed. As shown in FIG. 1a, a pair of holes is formed in facing portion 13, each of which is approximately ⅝-inch in diameter and positioned as shown. FIG. 1b illustrates an alternate embodiment in which angled brace 20 has a plurality of {fraction (7/16)}-inch holes formed in facing portion 23 and positioned as shown. FIG. 1c illustrates a further alternate embodiment in which angled brace 30 has a plurality of ⅜-inch holes formed in facing portion 33 and positioned as shown. Additional alternate embodiments using various numbers of holes can be used based on specific engineering requirements as determined by one skilled in the art.
An application showing use of such angled brace is illustrated in FIGS. 2[0028] a and 2 b. An angled brace, such as 30, is utilized as a bottom wall connector. A single or pairs 5 of wall studs 35 are attached through horizontal floor plate 38 using conventional construction methods. Brace 30 is attached to wall studs 35 by a plurality of lag screws 41. (If angled brace 10 is used, then lag screws 41 may comprise two ½-inch×3-inch lag screws. If angled brace 20 is used, then lag screws 41 may comprise four ⅜-inch×3 inch lag screws. If angled brace 30 is used, then lag screws 41 may comprise four {fraction (5/16)}-inch×3-inch lag screws.) Brace 30 is secured to foundation 45 by anchor 48. In a preferred embodiment, anchor 48 may be a ½-inch×5-inch threaded rod with epoxy adhesive as hereinafter described with reference to FIG. 3. In an alternate embodiment, anchor 48 may be a ½-inch×4½-inch compression anchor. Anchor 48 is fastened with a ½-inch hex nut 50 and a 2-inch×2-inch×⅛-inch washer 52.
Referring to FIG. 3, [0029] anchor 48 is embedded in foundation 45. Preferably, the foundation 45 is poured and floor plate 38 and foundation 45 are subsequently drilled to form a socket 55 to receive anchor 48. Socket 55 is partially filled with a suitable adhesive 59, for example, epoxy, polymers, expanding cements, etc. It is understood that foundation other than slab foundations are within the purview of this invention such as a basement or stem wall which may have a wood floor system between the bottom plate and the embedment into concrete. When using a threaded rod as the anchor 48, such rod should be embedded at least 3-inches into foundation 45.
An additional application showing use of such angled brace is illustrated in FIGS. 4[0030] a and 4 b. An angled brace, such as 30, is utilized as a top wall connector at the opposite end of such studs having a brace at the bottom end, as described with reference to FIGS. 2a and 2 b. A single or pairs of wall studs 35 are attached to horizontal ceiling plate 60 using conventional construction methods. Ceiling plate 60 may consist of a double plate as would be apparent to those skilled in this art. Brace 30 is attached to wall studs 35 by a plurality of lag screws 41. (If angled brace 10 is used, then lag screws 41 may comprise two ½-inch×3-inch lag screws. If angled brace 20 is used, then lag screws 41 may comprise four ⅜-inch×3-inch lag screws. If angled brace 30 is used, then lag screws 41 may comprise four {fraction (5/16)}-inch×3-inch lag screws.) Brace 30 is bolted to ceiling plate 60 by threaded bolt 63, such as a ½-inch×5-inch threaded bolt. Bolt 63 is fastened with a ½-inch hex nut 65 and a 2-inch×2-inch×⅛-inch washer 67, at top and bottom.
FIGS. 5[0031] a and 5 b illustrate an alternate embodiment for making a tie-down connection directly to a roof truss 70. A quick girder tie 73 is an angled galvanized metal tie presenting a plurality of holes for fastening such tie 73 to truss 70 using a plurality of nails as is known in the art. Tie 73 presents an angled extension having a single hole 74 approximately ⅝-inch in diameter in its center. A round shaft 75 approximately {fraction (11/16)}-inch in diameter is drilled in ceiling plate 60, concentric with such hole 74 in tie 73, to enable an elongated ½-inch steel rod 77 to extend through ceiling plate 60. Steel rod 77 is sufficiently long to embed in foundation 45 as described with relation to FIG. 3 and extend sufficiently above tie 73 to enable fastening with a 12-inch hex nut 81 and a 2-inch×2-inch×⅛-inch washer 84 for uplift forces less than 2400#. For uplift forces up to approximately 4800#, a 3-inch×3-inch×¼-inch washer should be used. Steel rod 77 should be embedded in foundation 45 with epoxy 59 to a minimum of 3 inches and 6 inches, respectively, depending on uplift force. In an alternate embodiment, tie 73 can be inverted and attached below ceiling plate 60 by nailing into studs 35 (FIGS. 4a and 4 b).
FIG. 6 shows a typical load bearing wall section employing the present invention. As described with reference to FIGS. 2 through 4, [0032] wall studs 35 may be single or doubled and serve to connect ceiling plate 60 with floor plate 38 to provide sufficient hold-down force for a structure. In a typical construction, a top and bottom connection, illustrated with bracket 30, would be used on each side of all load bearing exterior corners, within 12-inches of each corner and on each side of all openings 6-feet or greater. Such top and bottom connection would also be used at an average of 6-feet on center intervals in between and along bearing walls having uplift loads. This corresponds to approximately every fourth or fifth stud along such load-bearing wall. In an alternate embodiment, a single stud system with 1½-inch long lag screws can be used.
The invention has been described with references to a preferred embodiment. While specific values, relationships, materials and steps have been set forth for purposes of describing concepts of the invention, it will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the basic concepts and operating principles of the invention as broadly described. It should be recognized that, in the light of the above teachings, those skilled in the art could modify those specifics without departing from the invention taught herein. Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is intended to include all such modifications, alternatives and other embodiments insofar as they come within the scope of the appended claims or equivalents thereof. It should be understood, therefore, that the invention may be practiced otherwise than as specifically set forth herein. Consequently, the present embodiments are to be considered in all respects as illustrative and not restrictive. [0033]

Claims

What is claimed is:

1. A brace for connecting wood members in a building structure to strengthen such structure to conform to applicable building code requirements, such brace comprising:

a. a first connector means adapted for attaching such brace to a substantially horizontal construction member, comprising:

(1) a substantially horizontal portion having a hole disposed therein; and

(2) a threaded rod inserted through such hole having a fastener securing such substantially horizontal portion to such substantially horizontal construction member; and

b. a second connector means adapted for attaching such brace tie to a substantially vertical construction member, comprising:

(1) a riser extending substantially vertical at a right angle from such horizontal portion;

(2) a plurality of apertures disposed in such riser; and

(3) a plurality of fasteners attaching such riser to such substantially vertical construction member.

2. The brace according to claim 1, wherein:

a. such brace is manufactured of A36 grade steel.

3. The brace according to claim 1, wherein:

a. such plurality of fasteners attaching such riser to such substantially vertical construction member comprise lag bolts.

4. The brace according to claim 1, wherein:

a. such horizontal construction member comprises a floor plate.

5. The brace according to claim 4, wherein:

a. such threaded rod is further embedded in the foundation of such building.

6. The brace according to claim 1, wherein:

a. such horizontal construction member comprises a ceiling plate.

7. A tie down for use in construction of a wood frame building, comprising:

a. a first brace connected to the foundation of such building through a floor plate and attached to a building stud, and

b. a second brace attached to the building stud and connected to a ceiling plate, wherein

such first brace and such second brace provide sufficient strength to resist uplift forces according to applicable building code requirements.

8. The tie down according to claim 7, wherein:

a. such first brace and such second brace are manufactured of A36 grade steel.

9. The tie down according to claim 7, wherein:

a. such first brace is attached to such building stud by a plurality of fasteners; and

b. such second at brace is attached to such building stud by a plurality of fasteners.

10. The tie down according to claim 7, wherein:

a. such plurality of fasteners attaching such first brace and such second brace to such building stud comprise lag bolts.

11. A method of strengthening a wood frame building structure to resist high wind and seismic conditions, such method comprising the steps of:

a. forming a socket in the foundation of such structure through a floor plate of such building frame;

b. attaching a first brace to the bottom portion of a wall stud of such building frame, wherein

(1) a hole in a horizontal portion of such brace is aligned with such socket formed in the foundation, and

(2) such brace is further attached to the foundation by inserting a first attachment means through such hole into such socket and fastening such brace to the foundation;

c. forming an elongated tunnel through a ceiling plate of such building frame; and

d. attaching a second brace to the top portion of the wall stud of such building frame, wherein

(1) a hole in a horizontal portion of such brace is aligned with such elongated tunnel formed in the ceiling plate, and

(2) such brace is further attached to the ceiling plate by inserting a second attachment means through such hole and through such elongated tunnel and fastening such brace to the ceiling plate.

12. The method according to claim 11, wherein such first attachment means comprises:

a. a threaded rod embedded in the foundation and sealed in place by a suitable adhesive; and

b. an internally threaded fastener.

13. The method according to claim 11, wherein such first attachment means comprises:

a. a compression anchor embedded in the foundation; and

b. an internally threaded fastener.

14. The method according to claim 11, wherein:

a. such first brace is attached to such wall stud by a plurality of fasteners; and

b. such second at brace is attached to such wall stud by a plurality of fasteners.

15. The method according to claim 14, wherein:

a. such plurality of fasteners attaching such first brace and such second brace to such wall stud comprise lag bolts.