Patent Application
20250207383
The present invention relates to mechanisms for restraining wood members to effect moment resistance thereof. More particularly, the present invention is a wood-frame coupling that establishes substantial control of movement of wood members in manners necessary for certain novel structural applications.
It is well understood that wood material shrinks and expands with changing moisture content. It is this aspect of wood material that is the reason that effective moment resistant joints, i.e., restrained joints, have not been achieved for use in the building industry. It is also well understood that wood material containing high moisture content is more prone to decay especially when placed in contact with earth soil or cementitious material. Treatment of the wood material with preservatives has allowed restrained joint construction at the base of a wood column by burying a portion of the treated wood member in the ground and/or encasing within concrete of compacted soil. The structures constructed using this type of design are widely used and most often referred to as pole buildings. Typically, a significant fraction of the overall column length is buried in the ground to develop the resistance needed to resist lateral forces but may have limited life due to decay depending on the specific conditions. Large diameter logs (non-dimensional lumber) are typically not utilized in this manner and thus have not been utilized in a manner to support significant lateral forces, instead they are used to only support vertical forces.
Early composite wood-steel post base connectors anchored to a concrete foundation provide a basis for vertical reaction to forces applied to a dimension column (post) but provide little or no resistance to lateral forces applied to the post so they are not considered restrained joints or moment resistant joints. These types of connectors have been used for many decades and are still widely used. Other types of wood-steel composite connectors provide a means to support wood beams and rafters but do not provide moment resistance.
Other apparent attempts to address moment resistance limitations of wood members involve providing a basis for reactions to both vertical and lateral forces applied to a wood column base but are limited in capacity to resist fully resist lateral movement, especially for serviceability loading. The wood member is inserted into the connector and then screw fasteners provide significantly to the contact strength of the wood-steel interface. However, small movement i.e.; rotation, of the wood member can still occur until the larger moment resistance of the connector can fully engage. It is this type of small rotation movement at the column base that extrapolates to noticeable movements at the top of the column. This type of movement is not about the strength of the connector to resist seismic and wind lateral forces but instead to resist noticeable movement for occupied upper floors, for example, and may be referred to as serviceability. In addition, these newer types of connectors don't solve issues for shrinkage and swelling that will further add to the serviceability movement issue.
Other apparent attempts to solve moment resistance of wood members include the use of connectors for large sized timber and manufactured lumber column members. These connectors provide support reaction to significant vertical forces applied to large sized columns. They may also provide a level of lateral resistance, but the lateral resistance capacity is not sufficient for large forces and thus are not to be defined as fully restrained. These connectors do not account for variability associated with moisture that causes wood expansion, which limits serviceability and does not address moment resistance.
The prior efforts to improve wood member structural connections do not provide a basis suitable to be used for large diameter log columns to provide a fully restraint joint at the base of the member. As a result, the use of a log column within the building industry is typically limited to vertical forces. The log column can support significant vertical forces but provides little or no contribution to the structure for resisting lateral forces. Historical and current practices for installing log columns within structures use the overall building lateral force resisting system to support the log timber columns laterally. Alternatively, steel members might be installed and hidden within the log column to provide a basis for lateral control. The log columns, while still connected to a concrete foundation, provide little or no lateral resistivity themselves and they can be a burden during construction because they must be temporarily supported until connected to the structure for permanent support.
Given the limitations of the prior art for providing moment resistant wood connections for beams, beam splices have been cumbersome and difficult to construct and generally considered a defect in the overall span of the wooden beam member. They often result in a significant reduction in overall beam strength, especially if the splice is located mid-span. Based on the prior art available, it is widely perceived that such mid-span wood beam splice connections should be avoided. It would be desirable to provide a mechanism that can be used to effectively reinforce wood members so that splice connections could be used without a loss of structural integrity.
What is needed is an apparatus to impart moment resistance to a wood member. Also, what is needed is such an apparatus that can maintain the benefits of using wood members as building structural members without requiring extensive supplemental support to account for the moment resistance need. Further, what is needed is a method for making such an apparatus.
It is an object of the present invention to provide an apparatus to impart moment resistance to a wood member. It is also an object of the invention to provide such an apparatus that imparts moment resistance to the wood member to allow application of wood members in manners not previously considered. Further, it is an object of the present invention to provide a method for making such an apparatus.
These and other objects are achieved with the present invention, which is a wood-frame coupling frame apparatus in the form of a structural frame of suitable strength and stiffness compared to the equivalent wood material properties, that is arranged for engagement with at least one end of a wood member so that the frame effectively replaces the outer perimeter of the wood member. That is distinct from prior known wood member connection concepts for supporting and connecting structural wood members that position such connection apparatus around the outer perimeter of the wood member and most often secured with fasteners. The replacement of the wood member's outer perimeter with the coupling frame substantially eliminates gaps between the two components so that the wood member does not move laterally, vertically, or rotationally, with respect to the frame. The configuration and fabrication of the current invention results in a substantially uniform contained compression acting outward from the bulk of the contained wood throughout the surface area of the inner walls of the coupling frame, thus acting as substantially uniform outward pressure. The result is that the wood-frame coupling provides the end of the wood member with sufficient confinement that translates to sufficient stiffness to provide moment resistance capacity to the wood member that eliminate movement of the wood member relative to the frame under loads expected for a structure under lateral loading conditions.
The wood-frame coupling may be connected via the combination or via at least the frame to a separate rigid building element or suitable foundation. Doing so substantially eliminates movement of the wood member relative to the building element or foundation as the wood member of the coupling does not move with respect to the frame. By the present invention essentially eliminating movement of the wood member where it contacts the coupling frame when acted on by forces ranging from serviceability loading to ultimate stress capacity loading, the present invention offers a myriad of potential applications not available with wood given current wood construction practices.
The present invention also includes a method of making the wood-frame coupling apparatus with the frame replacing the wood member outer perimeter through fabrication of the wood-frame coupling that develops a compression stress at their interface, thereby creating a structural pressure bond between the two components. A portion of the overall work generated during the fabrication method is directed laterally inward from the frame walls into the wood while undergoing containment production. The coupling frame insertion process directs a fraction of the overall system generated compressive force inward over the wood surface area in the form of stress. The resulting strain is trapped within the walls of the coupling frame by the subsequent containment. The contained compressed wood is both member bulk and disturbed outer wood fibers. The compressive force acting laterally inward over the distance of strain is the work harnessed as trapped energy to act outward as substantially uniform pressure onto the wood-frame interface surface area creating the wood-frame couple. The use of mechanical advantage facilitates application of a strong axial compression force to the wood member acting generally parallel with the wood grain.
During this fabrication method, the wood member is placed in a braced or restrained condition for substantially its length while the coupling frame is forced with a load axial to the wood member length onto either or both ends of the wood member. The wood member is placed in a restrained/braced condition to prohibit bucking of the wood member caused by the high axial compression force required to cause the frame to replace the outer perimeter of the wood member. The axial force pushes the wood member into the frame (or the frame into and onto the wood member), so that the frame pushes into essentially the entire perimeter of the wood member lateral to the wood member's long axis, thereby removing a layer of wood material from the outer perimeter of the wood member at a selectable thickness. The selectable thickness is determined based on the difference between the frame's inner wall dimensions compared to the wood member outer surface dimensions.
As the coupling frame is forced into the wood member perimeter, it compresses and encases wood material while reducing the cross-sectional area of the wood member where the replacement occurs. This method by which the frame reshapes and encases the member's bulk volume where the two components are engaged requires work in the form of high lateral compressive stresses acting inward on the wood bulk volume moving the wood surface inward with the associated elastic strain. The resultant joining of the two components generates such compressed (contained) strain that the engagement cannot be dislodged. Therefore, the work required to compress the member over the width of the elastic deformation is conserved in the form of prestressed compression energy acting outward from the wood bulk volume onto the inner perimeter of the frame. This compression bond minimizes voids between the two material surfaces and provides minimal spaces for the wood member to move with respect to the frame.
The prefabrication method of the invention ensures the structural elements have been produced in a controlled environment resulting in specifiable properties, such as connection strength capacity and member movement resistance standards. In an embodiment of the invention, the prefabrication is carried out on wood members that are relatively dry, such as wood members of certified dryness. The prestressed wood already in compression only increases that compressive force if moisture permeates the fibers. Conversely, the compressive load generated by forcing the frame into the wood member perimeter substantially prohibits significant moisture permeation—thereby maintaining wood member integrity. Thus, the shrink-swell dilemma experienced by prior connection and joint apparatus attempting to restrain wood members is solved. Moreover, the compressive barrier blocking significant moisture permeation reduces or eliminates chemical degradation and biodegradation that often occur within the pores of wet wood over time. It also reduces the need to pressure treat structural wood members with hazardous chemicals.
A benefit of prefabricating the wood-frame coupling in a controlled environment eliminates limitations associated with existing processes for connecting and restraining wood members. Specifically, the prior art has commonly used a design approach to create connectors by configuring the steel components dimensions to closely match the dimensions of the connecting wood member and supplement the connection between the materials using fasteners in the attempt to make a tight connection. These connections are not conducive to prefabrication. Instead, the wood-steel connector apparatus are constructed in the field where there is variability at the wood-steel interface that increases the likelihood of the wood moving within the steel connector apparatus so that it would effectively provide no moment resistance, unlike the present invention.
Whereas the prior process requires the builder to attempt to match the inner perimeter of a connector apparatus to the outer perimeter of the wood member, the present invention produces the wood-frame coupling apparatus by taking the opposite approach. That is, the wood member outer perimeter is forced to change to match the inner perimeter of the reinforcing frame. It is the present invention's method of wood-frame coupling production; i.e., prefabrication, that facilitates the production of a series of prefabricated structural elements easily connected in a segmental installation manner to simplify and accelerate what as otherwise been a field construction process. On this basis, the present invention allows wood members to be utilized in applications previously not possible or avoided based on practicalities because the required magnitude of restraint needed was unattainable based on the prior art methods and technology.
The present invention utilizes the relative strength of the frame material compared to the wood member material in the coupling apparatus to allow the wood member to resist forces and loading in an enhanced manner compared to the prior art. The invention establishes a restraint joint component, which may also be referred to as a moment resistant component. The method of making the wood-frame coupling facilitates segmental construction for structural wood members in a variety of applications. Such applications include, but are not limited to, the following examples.
Pole (column) based structures (often called “pole barns” in certain applications) can now use the present invention as a prefabricated wood-frame coupling with flange adaptor that can easily connect the foundation flange thus creating a moment resistant base. This is opposed to current practices whereby wood columns are embedded into the ground with concrete and/or soil to create a moment resistant base. These current practices require treated wood given exposure to concrete and/or soils. Instead, using the present invention, the columns do not require the insertion into ground or concrete and so does require chemical treatment of the wood member. Often the structures constructed using pole or column based lateral resistance are occupied by people. The present invention can eliminate the potential exposure to preservative treatment chemicals when the columns are located in the walls or interior of the inhabited structure.
Pre-fabricated mid-span wood beam splices made with the wood-frame coupling can now be approximately as strong as unspliced beams with stiffness significantly increased for reduced deflection. Splices have been previously avoided because they are cumbersome and comparatively weak and unreliable. With the present invention, prefabrication allows easy and quick installation, perhaps easier to install than unspliced beams given the longer length. The more splices in a beam using the present coupling actually makes the beam stiffer with less deflection than can occur with existing wood beams. As a result, a spliced wood beam with one or more wood-frame couplings of the present invention may allow replacement of much heavier steel beams in certain applications, for example. The fact that the wood member's cross sectional dimension is reduced by the amount of perimeter wood thickness replaced by the present coupling frame reduces the capacity of the member to resist force induced stress at the location where the wood-frame ends does not necessarily translate into reduced force resisting capacity of the overall system. In most applications the slight reduction in wood member strength capacity is offset by the fact that the coupling frame length reduces the member length that is exposed to resist said forces. Given the deflection and acting moment stress magnitudes that result when the wood member resists applied forces are a function of the member length factored exponentially, the reduced cross section most often doesn't diminish the relative strength and stiffness when the overall member and coupling frame are considered.
Log columns prefabricated with a moment resistant base established using the wood-frame coupling of the present invention joined to a connection flange can now be utilized in the construction industry to allow large lateral and gravity forces to be resisted with log columns, with or without supplemental compression struts. Compression struts can optionally be used to further increase the laterally resisting capabilities of the column. The struts may be added to the pre-fabricated wood-frame coupling apparatus for large logs and timber columns when the support is based on a flanged configuration and the wood-frame coupling is smaller in cross section compared to the overall cross section of the log or timber column. Screw jack struts can be quickly connected to flange bolts to provide a compression force to supplement the wood-frame coupling to resist lateral forces. The entire coupling frame joint with struts already in place and pre-stressed can be delivered for one step installation onto a reception foundation flange.
Pre-fabricated flange connection to various forms of foundation reinforcement allows for simple base flange placement into concrete foundations, whether spread footing type or deeper drilled pier type foundations. Wooden moment frames, including portal frames, can now be constructed and eliminate the need for shear walls and bracing for the lateral resisting system where it makes sense. Restrained joints can now be used from the foundation connection through the column beam connections.
Segmental construction can be carried out using the wood-frame coupling with multiple beam and column lengths, prefabricated steel flanges, and additional bend fittings prefabricated for desired vertical and horizontal alignment at joints. Segmental framing for structures can be carried out using prefabricated elements including using one or more of the wood-frame couplings at strategic locations of the segmented construction using a simple tool set and fewer workers.
Log beams can be spliced with prefabricated splice/flanges adaptors allowing the same diameter log to span long distances without the natural log taper impacting the span length. Inverted truss technology can be applied by simply sandwiching the king post (as a flat bar) between the prefabricated beam splice flanges. Segmental construction of inverted truss systems allows on-site installation of high strength beams using relatively light weight transportable materials and members. Beam camber can be easily added as desired at the span joint by inserting a shim between the bean splice flanges.
Flanged steel columns members and wood members prefabricated with flanged wood-frame couplings of the present invention can be inter-mixed in configurations that leverage the steel strength where needed but still keep the overall construction relatively light weight given the large fraction of wood still utilized in the application. Applications where the capacity of long span wood beams are governed by deflection limits, not by moment capacity, may not need to be upsized if the wood-frame coupling splice is added to increase stiffness. This can reduce the cost to purchase and handle the long span glulam and other manufactured beams as well. Other structural wood columns using manufactured wood, such as cross-laminated timbers for example, may be designed into particular configurations using the wood-frame coupling of the present invention to provide restrained joints at column-column connections, column-beam connections, and column foundation connections.
The present invention may be described as relating to mechanisms for restraining wood members to effect moment resistance thereof. More particularly, the present invention is a coupling frame that is either inserted into and onto, or constructed onto an end of the wood member to enhance substantially the ability to control key physical properties of the wood member that are important for structural applications. Still more particularly, the inserted or constructed coupling frame completely engages with the entirety of the end of the wood member through full confinement of strain resulting from a strong compression force exerted during frame insertion or construction. Containment of the strained wood material translates into a substantially uniform contained compression acting outward from the wood bulk onto all inner surfaces of the frame creating a strong wood-frame couple. The contained compressive engagement between the wood and frame is permanent and limits all movement of the wood relative to the frame and reduces moisture access to the contained wood surface and interior.
The present invention may also be described as relating to mechanisms for restraining wood members to effect moment resistant joints thereof. More particularly, the present invention is a frame that is mechanically placed on an end of the wood member to enhance substantially the ability to control movement of the wood member that is important for structural applications. Still more particularly, the frame completely engages with the entirety of the end of a wood member through permanent containment of strain developed through the application of high intensity mechanically generated compression force applied during the fabrication of the wood-frame connection. The strain trapped within the wood-frame connection as work-energy is permanently maintained as high magnitude constrained compression that is a strong wood-frame couple. The compressive engagement between the wood and frame prohibits all movement of the wood relative to the frame, including laterally, axially, and rotationally, and reduces moisture intrusion into the contained wood. The use of the wood-frame couple to construct moment resistant joints for wood construction applications is a significant improvement compared with the prior art.
The invention includes a frame for making a wood-frame coupling to establish a joint that provides movement resistance and moment resistance to a wood member having an outer perimeter and an end, wherein the frame is coupled to the wood member at the end thereof. The frame includes a body including a wall characterized by an outer wall and an inner wall that establishes an inner perimeter. The wall defines an inner space within the inner wall configured to receive a portion of the end of the wood member therein. The wall is dimensioned so that the inner perimeter thereof is smaller in magnitude than the outer perimeter of the wood member at the end, and the wall of the body of the frame is arranged to replace an outer perimeter of the end of the wood member so that the wood member and the frame form the wood-frame coupling.
In an alternative embodiment of the wood-frame coupling, the frame includes a plurality of frame plates having edges. The plurality of frame plates are joined together to establish a body that establishes an inner perimeter about the outer perimeter of the wood member at the end thereof. The plurality of frame plates are joined together after placement about the end of the wood member to establish static contained compression of the end of the wood member at the outer perimeter thereof, so that the wood member and the frame established about the wood member form the wood-frame coupling.
In addition, an aspect of the invention is an apparatus for making a wood-frame coupling by joining together an end of a wood member and a frame. The apparatus includes a platform for removably retaining the wood member thereon, an axial load generator arranged to force the frame on and into the end of the wood member, a directional guide to control application and direction of the force generated by the axial load generator, an alignment guide to control relative movements of the end of the wood member and the frame, an axial wood restraint, and one or more lateral wood restraints arranged to secure the wood member to the platform while operating the axial load generator. It is noted that other types of apparatuses may be employed to make the wood-frame coupling.
The apparatus described above or another apparatus may be used to carry out a method of making the wood-frame coupling. The method involves making the wood-frame coupling for establishing moment resistance of the wood member by forcing the frame on and into an end of the wood member by carrying out the steps of securing the wood member to a platform, positioning the frame in contact with the end of the wood member, wherein an inner perimeter of the frame is substantially the same as an outer perimeter of the end of the wood member but smaller, and forcing the frame on and into the end of the wood member to establish the wood-frame coupling.
In another method, a prefabricated structural column is formed using the wood-frame coupling that includes the frame and the wood member joined together to establish moment resistance of the wood member, wherein the frame includes a flange. This method includes the steps of securing a structural body to a substrate, wherein the structural body includes the flange, positioning the wood member with the wood-frame coupling adjacent to the structural body, and securing the flange of the wood-frame coupling to the flange of the structural body.
The invention also includes a method of making a segmented structure formed of a plurality of wood members, wherein each wood member has at least one wood-frame coupling that includes the frame and the wood member joined together to establish moment resistance of the wood member. The method includes the step of securing the first wood member to the second wood member. The first wood member and the second wood member may be beams, or one may be a beam and the other may be a column. The wood members may be joined together at the wood-frame coupling or not. They may include flanges and the flanges may or may not be used to join the first wood member and the second wood member together.
The invention further includes a method of joining together a first wood member and a second wood member. Each wood member has at least one wood-frame coupling that includes a frame joined to at least one end of the wood member to establish moment resistance of the wood member beam. The method includes the steps of connecting a first end of a receiver to an end of one of the first wood member and the second wood member, wherein the receiver is arranged to receive therein the wood-frame coupling of the first wood member or the second wood member, and connecting a second end of the receiver to an end of the other of the first wood member and the second wood member, wherein the receiver connects the first wood member and the second wood member together.
The present invention includes production of prefabricated structural elements and members associated with specific applications of the wood-frame coupling as well as a method of segmental construction and installation utilizing said prefabricated elements and members. These and other features and advantages of the present invention will be understood by one of skill in the art upon review of the following detailed description, accompanying drawings, and appended claims.
A wood-frame coupling 10 of the present invention is shown in
The body 18 of the frame 12 includes a frame wall 26 that is characterized by an outer wall 28 and an inner wall 30. The thickness of the wall 26 is selectable dependent on the specific construction of the wood-frame coupling 10 as described herein. In an example embodiment of the invention, the thickness of the wall 26 is about ⅜-inch but not limited thereto. The length of the body 18 of the frame 12 is selectable dependent upon the cross-sectional area size and moment resistance required for the wood member 16. In an example of the invention, the length of the body 18 is about 12 inches so that the portion of the end 14 of the wood member 16 that enters the inner space 22 of the body 18 is about 12 inches when the end 14 substantially fills the inner space 22.
The wood member 16 is of selectable size and shape. The end 14 of the wood member 16 has a cross sectional area that is relatively the same as the cross sectional area of the body 18 of the frame 12 as measured at the outer wall 28. More specifically, the cross sectional area of the body 18 at the outer wall 28 is about the same as the cross sectional area of the end 14 of the wood member 16 but generally slightly larger depending on the body 18 material and thickness. When the wood-frame coupling 10 is formed, the body 18 and the wood member 16 are forced together so that the wall 26 of the body replaces an outer portion 32 of the perimeter of the end 14 of the wood member 16. Interior portion 34 of the end 14 of the wood member 16 is forced into the inner space 22 of the body 18. Wall 36 of the end 14 contacts substantially inner wall 30 of the body 18, resulting in substantially uniform constrained compression acting as pressure on the end 14 of the wood member, effectively preventing substantially any movement of the end 14 in the frame 12 and, correspondingly, substantially limiting any lateral or rotational movement of the entire wood member 16 based on the connection to body 18. The resulting constrained compression between inner wall 30 and end 14 is permanent pressure that can only increase in magnitude due to added moisture content of wood member 16 at end 14 from the initially substantially ensured dried condition if moisture content can increase when already experiencing a constrained compression environment.
The wood-frame coupling 10 formed as described herein may be used in a variety of ways to establish structural members of buildings, and other structures, tools, devices, etc., i.e., wherever useful, using wood in applications not considered before because moment resistant joints using wood were not available. The wood-frame coupling 10 forming a component of the wood member 16 enables usage of the wood member 16 with little or no reinforcement and to replace steel structural members in some instances. Example usages of the wood-frame coupling 10 are described herein but it is to be understood that the usage of the invention is not intended to be limited to these examples.
With reference to
Alternatively, strut 58 may also be connected to member 16 (
An option of the configuration of the couplings is shown in
It can be seen that the structural system represented in
While the spliced beam 80 is built by joining together adjacent wood-frame couplings 10,
A variant of the structure shown in
The wood-frame coupling 10 of the present invention provides a range of opportunities to improve certain building and other structural processes by enabling the use of more wood columns and beams as substantial structural members to support lateral forces by substantially establishing moment resistance in joints not previously considered for wood members. An aspect of the present invention for producing the novel wood-frame coupling 10 is the formation of the coupling 10. As illustrated in
The machine 300 includes a wood member support platform 302, axial force guides 301, an axial force generator 304, an adjustable axial restraint system 306 including end plates 303 and 316 and tieback shackling 305, coupling guide 307, and lateral restraints 308 to prevent wood member 16 buckling. The wood member support platform 302 is of selectable length and width chosen to support the wood member 16 and the forces acting axially, laterally, and rotationally during the coupling process thereon. The platform 302 is of sufficient structural integrity to support the weight of the wood member 16 with little to no bending or buckling while the frame 12 is being driven into and onto the end 14 of the wood member 16. Platform 302 must also be of sufficient structural integrity to assist with restraint of end plates 303 and 316 reactions to the applied force that is directed eccentric to the platform longitudinal axis. The platform 302 may be a manufactured structural steel member cut to length, such as a W-section wide-flange member or a C-channel section, or it may be a different manufactured configuration or made of another material.
The axial load generator 304 is a double acting hydraulic cylinder (engine powered with hydraulic pump, fluid reservoir tubing, etc. not depicted) with sufficient axial compression loading capacity to push piston rod 312 to at least about 60,000 lbs. of force, with actual capacity requirements dependent on size and configuration of wood member 16 and frame 12 and depth of perimeter wood material removed from end 14 of wood member 16 by frame 22. Piston rod 312 is connected to a platen 310, with hydraulic cylinder base connected to end plate 303 at end 316 and platen 310 rigidly affixed to piston rod 312. The platen 310 is sized and of sufficient integrity to maintain contact with the flange 20 of the coupling 10, or the bottom of the body 18 if the coupling 10 has no flange, or platen 310 may be substituted with an alternative configurated load distributing element rigidly affixed to piston rod 312 with configuration and structural integrity sufficient transfer load from piston 312 to frame 22 without damaging other optional appurtenances potentially already connected to body 18 and also configured such that the platen 310 or alternative element is guided on loading directional tracks 301 connected to platform 302.
The piston 312 forms part of the force generator 304 and is selected in conjunction with the engine and hydraulic pump to apply sufficient loading to the frame 22 to force it on and into the wood member 16 at the end 14 to fabricate wood-frame coupling 10. The axial restraint system 306 includes two end plates 303 affixed to each end 314 and 316 of the platform 302 along with removable axial force resisting removable inserts for adjusting length of wood member 16 prior to fabricating wood-frame coupling 10. End plates 303 at platform ends 314 and 316 must be connected to the platform 302 and tieback shackling 305 with sufficient structural capacity to resist both tension reaction forces in the tieback shackling 305 and tension reaction forces in platform 302. Moreover, platform 302 must be of sufficient structural integrity and stiffness to also resist extreme compression forces and resultant platform buckling from occurring from undesired eccentric loading directed to end plates 303.
The one or more lateral wood restraints 308 may be fixed or metal straps that are secured about the perimeter of the wood member 16 and connected to platform 302 or another suitable anchoring support during the wood-frame coupling fabrication process. The structural integrity, number, and spacing of the lateral wood restraints is selectable but must be sufficient to substantially prevent bending, buckling, or other lateral, horizontal, or vertical movement of the wood member 16 while on the platform 302 and the generator 304 is activated to cause movement of the frame 12 onto the end 14 of the wood member 16. Coupling guide 307 ensures accurate joining of the frame 12 into and onto wood member 16.
The wood-frame joining machine 300 is used to carry out a method of the present invention for making the wood-frame coupling 10. The method includes a step of placing the wood member 16 on the platform 302. Before or after that step, end 14 of the wood member 16 is optionally scored at least partially around its perimeter to produce slits in the wood member 16 at the end 14. This scoring of the wood member 16 facilitates insertion of the frame 12 on and into the wood member 16 at the end 14 as relief joints. The scoring is optional as dependent on the loading capability of the axial load generator 304, dimensions of wood member 16 and frame 22 and the depth of perimeter wood material removal desired to create the coupling. The wood member 16 is preferably kiln dried or otherwise dried to a satisfactory moisture content prior to placement on the platform 302. The method may be performed as a prefabrication method in a controlled environment rather than on a job site but is not limited thereto.
With the wood member 16 on the platform 302, the axial restraint 306 is connected in correct configuration. The one or more lateral wood restraints 308 are secured about the perimeter of the wood member either in complete or partial contact with the wood member 16 except at the end 14. The frame 22, may optionally be first heated to induce minor quantities of thermal expansion to add a small magnitude of additional permanent strain to the final wood-frame coupling to supplement the constrained compression coupling depending on specific or special applications or environments where the wood-frame coupling 10 will be utilized. Using wood member 16 elements containing unknown moisture content at time of coupling fabrication should be avoided unless specifically allowable for the intended application or the wood-frame coupling bond will be augmented using attachment means such as fasteners such as screws or bolts, adhesives, such as epoxy adhesives, or the like, connecting through frame 22 to end 14 of wood member 16 in a configuration determined sufficient to provide the additional connection capacity potentially needed for the intended application. Moreover, even if initial moisture content at coupling fabrication does not present a concern for future shrinkage, the wood-frame coupling 10 can nevertheless be enhanced by adding such fasteners, adhesives, or the like thereto.
The frame 12 is positioned in contact with the bottom of the wood member 16 at the end 14 and aligned by the coupling guide 307 that is constructed and attached to the apparatus in a manner and with sufficient strength and stiffness to restrain frame 12 from deviating off proper course into and onto wood member 16 at end 14 until sufficient connection length of frame 12 on wood member 16 prohibits any course deviation. That positioning is made to ensure that the inner perimeter of the frame 12 is substantially aligned with the outer perimeter of the wood member 16 at the end 14. Once that alignment is confirmed, the platen 310 of the generator 304 is placed in contact with the base of the flange 20, or directly with the base of the body 18 if there is no flange 20. The generator 304 is activated and the piston 312 actuated to move the platen 310 along the force directional guide tracks, which moves the frame 12 so that it is forced on and into the end 14 of the wood member 16 while guided by coupling guide 307. In the early stages, the movement of the piston 312 may be halted periodically to confirm maintenance of the frame-wood alignment with the understanding that frame 22 inserted even a small fraction of the full frame insertion distance on or into end 14 of wood member 16 may be sufficient to prohibit alignment adjustments. The piston 312 and the platen 310 are retracted when the frame 12 is fully or effectively on and in the end 14 of the wood member 16. The wood member 16 may then be removed from the platform 302 and the establishment of the wood-frame coupling 10 then confirmed.
A first embodiment of a moment resistant beam-column connection 400 using the wood-frame coupling 10 is shown in
A second embodiment of a moment resistant beam-column connection 500 using the wood-frame coupling 10 is shown in
A third embodiment of a moment resistant beam-column connection 600 using the wood-frame coupling 10 is shown in
The receiver 702 is similar to other such receivers described herein and further includes a plurality of set bolts 718 removably insertable into set bolt ports 720 of the receiver 702. The set bolts 718 are used to secure the receiver 702 to the woodframe coupling 10 of the beam 704 as shown by tightening them to the wood-frame coupling of the first end of the beam 704. Alternatively or additionally, the receiver 702 may also include set bolts for securing the receiver 702 to the wood-frame coupling 10 of the first column 706.
Each of the beam coupling 712 and the column coupling 714 may be the wood-frame coupling 10 as described herein and configured substantially as shown for the connection 400 of
The wood-frame coupling 10 previously described herein involves the use of a preformed version of the frame 12, wherein the frame 12 is forcibly coupled to the end 14 of the wood member 16. An alternative embodiment of a wood-frame coupling 800 is shown in
It is to be noted that the joining together of the wood member and the frame to form any of the wood-frame couplings described herein may be augmented with fasteners, such as screws, bolts, or the like. Ports for receiving such fasteners may be formed into at least the frame if only set bolts are used for augmented securing and, optionally, into the frame and wood when augmented securing is provided by through bolts, prior to making the wood-frame coupling. The ports may alternatively be formed into the coupling after the frame and wood member are joined together.
While the present invention has been described with respect to specific example embodiments, it is not intended to be limited thereby. Instead, the scope of the invention is established by its definition in the accompanying claims and equivalents.
