Wood-concrete composite connectors and ductile reinforcement supports

Abstract

A connector for a wood-concrete composite floor or roof system is provided that combines mechanical and adhesive bonding to the wood board substrate to provide high coefficient of slip stiffness and resilience, while exhibiting ductile structural behavior under ultimate loads. It also provides a unified method for supporting concrete slab reinforcement members during fresh concrete pouring.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates generally to floor and roof structural assemblies constructed from a wood board substrate and a concrete topping slab that are joined together to function as a composite structural system to resist constant and variable loads. [Background technology]

[0002] In wood-frame buildings, concrete topping slabs are often installed over wood floor systems to improve the floor system's acoustic, vibration, and fire resistance. These concrete topping slabs are either installed non-structurally or structurally connected to the wood substructure to form a composite system that further improves the strength, rigidity, and fire resistance of the floor system. These systems are commonly referred to as "wood-concrete composite" or "TCC" floor and roof systems.

[0003] The performance (strength, stiffness, vibration, fire resistance, and sound insulation) of a wood-concrete composite floor and roof system is significantly affected by the connection method between the wood board substrate and the concrete topping slab. The connection method selected also affects the construction cost, labor, and construction logistics of the composite floor and roof system. Common TCC connection methods include shear keys to the wood board substrate, protruding nails and screw fasteners, mechanical fasteners, and adhesive bonded fasteners. Each of these connection methods involves a trade-off between performance and cost. Summary of the Invention [Problem to be solved by the invention]

[0004] The structural design of a TCC floor and roof system is typically dictated by the composite stiffness of the system. The composite stiffness is affected by the slip coefficient (horizontal shear deformation at the wood-concrete interface under load) of the wood-concrete joint. Connectors with a high slip coefficient for the connecting members provide a rigid bond that maximizes structural performance. Improving the performance of a TCC floor system reduces the amount of wood required, lowering overall costs.

[0005] TCC floor and roof systems are statically indeterminate structures. High-stiffness connectors are subject to significant loads during extreme load (or strength) events, such as the maximum potential live load due to service. Connectors that exhibit ductile behavior (e.g., headed steel shear studs welded to steel beams and embedded in the concrete deck above the steel beams) exhibit predictable deflection during extreme load events, minimizing the ultimate design force resisted by the connectors. This ductile behavior allows for fewer connectors to be used, reducing the cost and labor associated with installing the system.

[0006] Concrete topping slabs are typically reinforced with rebar bars or welded wire mesh, which require vertical support during the pour of fresh concrete. Reinforcement support shoring is typically constructed from steel wire or plastic members, shaped to hold the reinforcement in place when tied to the shoring with standard steel wire. The TCC Connector, which also functions as a reinforcement shoring, reduces the overall cost of the composite system by eliminating the need for traditional shoring.

[0007] Large wooden floor panels are typically installed by crane and lifted with temporary steel lifting devices fixed to the floor panels. TCC floor connectors can be used as an alternative to temporary lifting connectors if they have suitable attachment points and sufficient load capacity, reducing the installation time and cost of large wooden floor panels. [Means for solving the problem]

[0008] Disclosed herein are one or more inventions relating to wood-to-concrete floor-roof connectors that exhibit high stiffness (slip coefficient) and ductile ultimate load (or strength) behavior, methods for their manufacture and resulting shape variations, and methods for supporting concrete slab reinforcement. More specifically, disclosed are connectors between wood board substrates and composite concrete topping slabs that provide a nearly rigid connection under service loads and exhibit ductile structural behavior under ultimate loads, support reinforcement in the topping slab, and can replace temporary lifting hardware.

[0009] The TCC connectors disclosed in this invention are referred to herein as wood-concrete composite bearing ("TC3") connectors or TC3 connectors, which are designed to be embedded in a concrete slab and to secure or join a concrete slab and a wood board substrate, as described herein.

[0010] The TC3 Connector maximizes the performance of the TCC system by providing a high-rigidity bond between the wood board substrate and the concrete topping slab. This high-rigidity bond combines mechanical and adhesive bonding, making it easy to install and highly resistant to fire.

[0011] The TC3 Connector provides a ductile connection between the wood board substrate and the concrete topping slab, allowing deformation during extreme load events. Deformation of the system occurs at the relatively thin profiled top bar.

[0012] The TC3 connector provides support for concrete slab reinforcement during the placement of fresh concrete.

[0013] The TC3 connector has a consistent geometric module but may vary in length depending on the stiffness and load requirements of the composite system.

[0014] The TC3 connector does not preclude the installation of a sound insulating layer between the wood substrate and the concrete topping slab.

[0015] TC3 Connectors can be installed in a variety of wood, timber and bamboo substrates. TC3 Connector fasteners can also penetrate wood, timber and bamboo substrates to connect underlying wood and timber beam and framing members.

[0016] The TC3 connector can be pre-installed in prefabricated panels at the factory or installed on-site as part of traditional building methods.

[0017] The TC3 connector replaces temporary lifting hardware for on-site installation of large timber floor panels.

[0018] As used herein, "wood" includes wood materials that are solid sawn or heavy lumber, as well as cross-laminated lumber (CLT), glue-laminated lumber panels (GLT), nail-laminated lumber (NLT), dowel-laminated lumber (DLT), laminated veneer lumber (LVL), mass plywood panels (MPP), glue-laminated lumber (Glulam), parallel strand lumber (PSL) and similar products.

[0019] "Composite" refers to a structural system that is composed of two different materials, such as wood and concrete, that are joined together to function as a single structural member or system.

[0020] "Adhesives" means products used to bond materials such as wood and steel together, including two-part epoxies, acrylic adhesives, general-purpose construction adhesives, pressure-sensitive adhesive tapes, and similar products.

[0021] "Fastener" means a product used to join wood members and includes conventional screws, self-tapping screws, nails, lag bolts, studs, staples, and similar products.

[0022] "Chair" means an object intended to temporarily support and reinforce reinforcing steel bars in a concrete slab while fresh concrete is being poured.

[0023] "Ductility" refers to the ability of a structural member to continue to deform while deflecting under load and to maintain the load at the point of deflection.

[0024] "Slip coefficient" refers to the shear stiffness of a joint at the interface of two joined materials, such as the interface between a wood substrate and a concrete topping slab. The coefficient has units of load divided by displacement.

[0025] "Normal service load" means the maximum service load that a structure or equipment is designed to undergo during normal use, as that term is commonly understood in the construction industry.

[0026] "Ultimate load" or "ultimate load value" is a term commonly understood in the construction industry that means a statistically unlikely load in excess of the maximum working load that a structure or device is designed to withstand. These are sometimes also called "factored loads" because they are a predetermined factor greater than the maximum working load.

[0027] In one embodiment, the TC3 connector includes a steel base plate rigidly connected to a wood board substrate with adhesive and mechanical fasteners, and a ductile steel top bar connected to or formed from the steel base plate that supports reinforcement in a concrete topping slab.

[0028] In a preferred embodiment, the TC3 connector has a repeatable geometric module that simplifies mass production of connectors of different lengths.

[0029] In the preferred embodiment, the TC3 connector is attached to a wooden floorboard (with no joists directly underneath) using short vertical mechanical fasteners.

[0030] In the preferred embodiment, the TC3 connector is attached directly to the wooden floorboards and joists below using long, angled mechanical fasteners.

[0031] In a preferred embodiment, the TC3 connectors are bonded to a wood board substrate in a uniform or non-uniform grid that positions the connectors based on the shear demands within the composite system.

[0032] In some embodiments, a non-structural acoustic barrier is provided at the wood-to-concrete interface, but is discontinuous at the intermittent TC3 connectors.

[0033] In some embodiments, the top bar is formed from the base plate by pushing, stamping, or expanding a portion of the base plate metal to form a ductile seat shape.

[0034] In some embodiments, the top bar and base plate are made by bending or folding a single sheet of metal that has been notched to form the shape of the ductile seat.

[0035] In some embodiments, the base plate is secured using conventional screws, self-tapping screws, nails, lag bolts, studs, staples, and similar products.

[0036] In some embodiments, the base plate is adhered using two-part epoxies, acrylic adhesives, general purpose construction adhesives, self-adhesive "peel and stick" tapes, and similar products.

[0037] In some embodiments, alternative bio-based materials, such as bamboo, are used as substrates to replace wood.

[0038] In some embodiments, an alternative concrete topping slab, such as lightweight concrete or gypsum concrete, is bonded to the wood board substrate.

[0039] In some embodiments, the reinforcement in the topping slab consists of deformed rebar, welded wire mesh, post-tensioning cables, carbon fiber rods, fiberglass rods, or basalt rods.

[0040] In some embodiments, the connector may be constructed of a reinforced plastic composite instead of steel.

[0041] Those skilled in the art will understand, or will come to understand, other systems, methods, features and advantages of the disclosed invention(s) upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.

[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the system disclosed herein and, together with the description, explain the advantages and principles of the disclosed system. [Brief explanation of the drawings]

[0043] [Figure 1A] FIG. 1A is a perspective view of a first embodiment of a TC3 wood-concrete composite connector with ductile reinforcement bearings embodying the principles described herein. [Figure 1B] FIG. 1B is an exploded view of FIG. 1A. [Figure 2A] FIG. 2A is a plan view of FIG. 1A. [Figure 2B] FIG. 2B is a front view of FIG. 1A. [Figure 2C] FIG. 2C is a cross-sectional view of FIG. 1A. [Figure 3A] Figure 3A is a plan view of a second embodiment of the TC3 wood-concrete composite connector with ductile reinforcement bearings embodying the principles described herein, in which the top bar is stamped, stamped, or expanded from the metal of the base plate. [Figure 3B] FIG. 3B is a front view of a second embodiment of the TC3 connector. [Figure 3C] FIG. 3C is a cross-sectional view of the TC3 connector of the second embodiment. [Figure 4A]4A is a plan view of a third embodiment of the TC3 wood-concrete composite connector with ductile reinforcement bearings embodying the principles described herein, in which the top bar and base plate are formed from a single sheet of metal that is cut and bent or folded to form the base plate and top bar shapes. [Figure 4B] FIG. 4B is a front view of the TC3 connector of the third embodiment. [Figure 4C] FIG. 4C is a cross-sectional view of the TC3 connector of the third embodiment. [Figure 5A] 5A is a plan view of a fourth embodiment of a TC3 wood-concrete composite connector with ductile reinforcement bearings embodying principles described herein, where the top bar shape is partially cut from the base plate and bent upward to its final position. [Figure 5B] FIG. 5B is a front view of a fourth embodiment of the TC3 connector. [Figure 5C] FIG. 5C is a cross-sectional view of the TC3 connector according to the fourth embodiment. [Figure 6A] Figure 6A shows a plan view of a fifth embodiment of the TC3 wood-concrete composite connector with ductile reinforcement bearings embodying the principles described herein. In this configuration, the top bar replaces the base plate and is embedded in a shear key within the mass timber substrate. [Figure 6B] FIG. 6B is a front view of the TC3 connector according to the fifth embodiment. [Figure 6C] FIG. 6C is a cross-sectional view of the TC3 connector according to the fifth embodiment. [Figure 7A] FIG. 7A is a cross-sectional view of a TC3 connector embodying the principles disclosed herein, installed on a CLT substrate and supporting a reinforcing bar with a sound-insulating mat sandwiched between the wood and concrete. [Figure 7B] FIG. 7B is an exploded cross-sectional view of FIG. 7A. [Figure 8]FIG. 8 is a perspective view showing a TC3 connector embodying the principles disclosed herein installed in a typical section of a CLT board, supporting rebar with a sound-insulating mat sandwiched between the wood and concrete. [Figure 9] FIG. 9 is an exploded view of FIG. [Figure 10] FIG. 10 is a perspective view of a uniform grid of TC3 connectors embodying the principles disclosed herein installed in panels throughout a floor system. [Figure 11A] FIG. 11A is a perspective view of a TC3 connector embodying the principles disclosed herein, with angled screws, for passing through a wood deck and connecting to a wood beam below. [Figure 11B] FIG. 11B is a perspective view of a second embodiment of a TC3 wood-concrete composite connector with ductile reinforcement bearings embodying the principles presented herein, where the top bar is stamped, punched, or expanded from the metal of the base plate. [Figure 11C] 11C is a perspective view of a third embodiment of the TC3 wood-concrete composite connector with ductile reinforcement bearings embodying the principles disclosed herein, in which the top bar and base plate are formed from a single sheet of metal that is cut and bent or folded to form the shape of the base plate and top bar. [Figure 12A] FIG. 12A is a front view of a first embodiment of a TC3 connector embodying the principles disclosed herein, with angled screws attached to the top of a CLT deck substrate and threaded through to connect to a wood beam below. [Figure 12B] FIG. 12B is an exploded view of FIG. 12A. [Figure 13] FIG. 13 is a perspective view of a first embodiment of a TC3 connector embodying the principles disclosed herein, in which angled screws are attached to the top of a CLT deck substrate and threaded through to connect to a wood beam below. [Figure 14] FIG. 14 is an exploded view of FIG. [Figure 15]FIG. 15 is a perspective view of the first embodiment TC3 connector installed along a timber beam supporting a CLT deck in an overall floor system. [Figure 16A] Figure 16A is an elevation view showing a mass timber panel with TC3 connectors installed at the factory and loaded for shipment. [Figure 16B] Figure 16B is a perspective view showing the lifting of a mass timber panel using TC3 connectors as attachment points for the crane lifting equipment. [Figure 17] FIG. 17 is a diagram illustrating truss forces acting on a TC3 connector module with ductile stiffening seats embodying principles described herein. [Figure 18A] FIG. 18A illustrates the expected ductile behavior of a TC3 connector with ductile reinforcement bearings embodying principles described herein, showing the shear load demand and shear deformation at the wood-concrete interface. [Figure 18B] FIG. 18B illustrates the expected ductile behavior of a TC3 connector with a ductile reinforcing seat embodying the principles described herein. DETAILED DESCRIPTION OF THE INVENTION

[0044] Referring now to the accompanying drawings, one or more embodiments using one or more wood-concrete composite connectors consistent with the principles disclosed herein will be described in detail.

[0045] FIG. 1A is a perspective view of a first TC3 connector 1 with ductile reinforcement bearings. The TC3 connector 1 includes a steel base plate 1A, the bottom of which is attached to a wood board substrate using a combination of adhesive (not shown) and mechanical fasteners 1D that pass through holes 1E in the plate (shown in other figures). A steel top bar 1B has a curved profile with a repeating module 1F, provides support for reinforcement bars 2A and 2B (shown in other figures), and is connected to the concrete topping slab by adhesive and direct support. The TC3 connector 1 and other TC3 connectors described herein are embedded in the poured concrete topping slab. The steel top bar 1B is bonded and secured to the steel base plate 1A by structural welds 1C. The overall length of the connector and components 1A and 1B is variable and can be set to any length required by the design.

[0046] The base plate preferably has a generally planar shape, or at least a generally planar bottom surface, thereby providing an effective plane. The through-holes in this embodiment have longitudinal axes that are perpendicular to the effective plane of the base plate. In other embodiments described below, the longitudinal axes are preferably oriented non-perpendicular to the effective plane of the base plate.

[0047] The adhesive used to secure the base plate to the wood board substrate preferably comprises two-part epoxy resins, acrylic adhesives, general purpose construction adhesives, adhesive tapes, and similar products as required by the design.

[0048] The curved profile is preferably continuous and smooth to avoid weak points and simplify manufacturing. Module 1F includes a recess or seat 1G for receiving and supporting a reinforcing bar, as shown in the other figures. Two modules 1F are separated by an inverted curve 1H. Thus, bar 1B has an overall wavy or sinusoidal profile.

[0049] Although the bar member 1B is shown as a deformed rectangular bar, it may have any suitable cross-sectional shape, such as a circular cross-sectional shape. The bar is preferably made of a steel material that exhibits good plastic deformation behavior or ductility under ultimate load, for reasons discussed below. The steel material for the bar may be made of a common carbon steel, such as ASTM-A36 or ASTM-A572, or a stainless steel, such as ASTM-A316.

[0050] Figure 1B is an exploded view of the TC3 connector 1 of Figure 1A, showing the steel base plate 1A, ductile steel top bar 1B, structural welds 1C, mechanical fasteners 1D, and through holes 1E.

[0051] FIG. 2A is a top view of the TC3 connector 1 of FIG. 1A, showing the top surface of the steel base plate 1A, the ductile steel top bar 1B, the structural welds 1C on both sides of the top bar 1B, and the mechanical fasteners 1D. In this embodiment, the mechanical fasteners 1D are shown as screws. However, as shown in another embodiment (discussed below), the mechanical fasteners could also be nails. Other types of mechanical fasteners could also be used as appropriate to meet a particular structural design.

[0052] FIG. 2B is a front view of the TC3 connector 1 of FIG. 1A taken along line 2B-2B of FIG. 2A.

[0053] FIG. 2C is a cross-sectional view of the TC3 connector 1 of FIG. 1A taken along line 2C-2C of FIG. 2A. FIG. 2C also shows a first reinforcing bar 2A housed in the support portion 1G of the module 1F. The first reinforcing bar 2A extends in a first direction intersecting the extension direction of the top bar 1B and the TC3 connector 1. A second reinforcing bar 2B is housed above the first reinforcing bar 2A. The second reinforcing bar 2B extends in a direction intersecting the extension direction of the first reinforcing bar 2A. In a preferred embodiment, the first and second directions are orthogonal to each other. However, in other embodiments, they may not be orthogonal to each other. Also, preferably, the extension direction of the first reinforcing bar 2A is orthogonal to the extension direction of the TC3 connector 1. However, in other embodiments, the extension direction of the first reinforcing bar 2A is not orthogonal to the extension direction of the TC3 connector 1. The first reinforcing bar 2A, which is next to the second reinforcing bar 2B, is placed on top of the top bar 1B and secured with conventional cable ties. The second reinforcing bar 2B may be secured to the first reinforcing bar 2A and / or the top bar 1B with the same cable ties or one or more other cable ties.

[0054] FIG. 3A is a plan view of a second TC3 connector 3. This TC3 connector 3 is a manufacturing alternative to the TC3 connector 1. In the TC3 connector 3, the top bar 3B is stamped, stamped, or expanded from the metal of the base plate 3A. As a result, no welding is required to join the base plate 3A and top bar 3B, since they are integrally formed from the same sheet of metal. Preferably, mechanical fasteners 3D are located on the continuous portion of the base plate 3A between the modules 3F.

[0055] 3B is a front view of the second TC3 connector 3, showing where the top bar 3B is stamped, punched or expanded from the metal of the base plate 3A. Each module 3F includes a seat 3G for receiving a first stiffening bar 2A as previously described.

[0056] FIG. 3C is a cross-sectional view of the second TC3 connector 3, showing where the top bar 3B is extruded, stamped, or expanded from the metal of the base plate 3A. This cross-sectional view shows the area removed from the base plate 3A to form the top bar 3B. This view also shows the placement and positioning of the first transverse reinforcing bar 2A and the second longitudinal reinforcing bar 2B, as previously described. The second longitudinal reinforcing bar 2B can also be secured to the first reinforcing bar 2A and / or the top bar 3B using the same wire tie or one or more other wire ties.

[0057] 4A is a plan view of a third TC3 connector 4. In this connector, the top bar 4B and base plate 4A are cut from a single sheet of metal and then bent or folded to form the shape of the base plate 4A and top bar 4B. The base plate 4A and top bar 4B are formed from a continuous sheet of material. At least a portion of the base plate 4A can be bonded or secured to a wood substrate with adhesive (not shown) and mechanical fasteners 4D.

[0058] 4B is a front view of the third TC3 connector 4, in which the top bar 4B and base plate 4A are formed by cutting a single sheet of metal and then bending or folding it into the shape of the base plate 4A and top bar 4B. In this view, the cut pattern 4C that gives the top bar 4B ductile behavior is easily visible.

[0059] 4C is a cross-sectional view of a third TC3 connector 4, in which the top bar 4B and base plate 4A are formed by cutting a single sheet of metal and then bending or folding it into the shape of the base plate 4A and top bar 4B. The gap between the generally perpendicular cross sections shown in this figure, i.e., the distance 4G between opposing base plate cross sections 4A-1 and 4A-2, can vary depending on manufacturing preferences and constraints.

[0060] As can be seen in FIGS. 4A and 4B, the metal plate is preferably first provided with two parallel rows of cut patterns or notches 4C located on either side of the metal plate's axis of symmetry. The metal plate is then bent or folded along the axis of symmetry to the desired bend or fold angle. As shown, the bending process preferably does not include sharp creases, as these may create undesirable weaknesses or breakage points in the top bar 4B. Before or after such bending, the outer edges of the metal plate may be bent or folded to form the parallel base plate portions 4A-1 and 4A-2 and the defining portions of the top bar 4B. Again, this bending or folding is performed to avoid creating sharp creases, which would otherwise create undesirable weaknesses or breakage points. The defining portions of the top bar 4B are then cut or deformed at each module 4E to include recesses or indentations that define the support 4E.

[0061] As with conventional TC3 connectors, each seat 4E is configured to receive a first reinforcing bar 2A, which can be secured to the top bar 4B with a wire tie as described above. A second reinforcing bar 2B can also be secured to the first reinforcing bar 2A and / or the top bar 4B using the same wire tie or one or more other wire ties.

[0062] As shown, the mechanical fasteners 4D may alternatively be nails rather than screws.

[0063] Figure 5A is a plan view of a fourth TC3 connector 5, which is a manufacturing alternative to the TC3 connector 1. In the TC3 connector 5, the top bar 5B is partially cut with a pattern 5C and then bent upward from the metal of the base plate 5A. As a result, no welding is required to join the base plate 5A and top bar 5B, because they are integrally molded from the same plate. As with the conventional TC3 connector, the base plate is connected to the mass timber substrate with adhesive (not shown) and mechanical fasteners 1D.

[0064] 5B is a front view of the fourth TC3 connector 5 showing the components mentioned above, including the profile of the top bar 5B, which has a recess 5C in the profile that provides a stiffening seat support.

[0065] Figure 5C is a cross-sectional view of the fourth TC3 connector 5, showing, in addition to the elements mentioned above, a first reinforcing bar 2A that can be secured to a top bar 5B with a wire tie, and a second reinforcing bar 2B that can be secured to 2A with a wire tie.

[0066] Figure 6A is a plan view of a fifth TC3 connector 6, a manufacturing alternative to TC3 connector 1. In TC3 connector 6, the top bar 6B is formed from a bent corrugated metal profile. The lower flat portion of the corrugated profile is positioned within a recessed shear key 5A in the mass timber panel below. As a result, a base plate is not required to achieve the connector's design requirements. As with the conventional TC3 connector, this connector is connected to the mass timber substrate by adhesive and mechanical fasteners 1D within the shear key 5A (not shown).

[0067] Figure 6B is a front view of the fifth TC3 connector showing the elements mentioned above, including the profile of the top bar 6B, which has a recess 6C that provides a stiffening seating support.

[0068] 6C is a cross-sectional view of the fifth TC3 connector 6, showing the components described above, as well as a first reinforcing bar 2A that can be secured to the top bar 5B with wire ties, and a second reinforcing bar 2B that can be secured to 2A with wire ties.

[0069] 7-16 illustrate the placement and use of the TC3 connectors disclosed herein on a CLT substrate in accordance with the principles disclosed herein, using one or more TC3 connectors with ductile reinforcement seats embodying the principles presented herein. It will be readily appreciated that similar principles apply to all of the TC3 connectors disclosed herein, as well as other connectors embodying the principles disclosed herein.

[0070] FIG. 7A is a cross-sectional view of a TC3 connector 1 installed on a CLT substrate 7A and supporting reinforcing bars 2A and 2B with a sound-insulating mat 7B sandwiched between a wood layer 7D and a concrete topping slab 7C.

[0071] FIG. 7B is an exploded view of FIG. 7A.

[0072] Figure 8 is an isometric view of the TC3 connector 1 installed on a typical section of CLT substrate 7A, with sound insulation mat 7B positioned between the wood layer 7A and a concrete topping slab 7C, supporting reinforcement bars 2A and 2B.

[0073] Figure 9 is an exploded view of Figure 8, showing the CLT substrate 7A, optional acoustic insulation layer 7B, adhesive-backed steel base plate 1A, mechanical fasteners 1D, ductile steel top bar 1B, concrete reinforcing bars 2A and 2B, and concrete topping slab 7C.

[0074] Figure 10 is an isometric view of a uniform grid of TC3 connectors 1 installed in the panels of an overall floor system, showing the CLT substrate 7A, optional acoustic insulation layer 7B, concrete topping slab 7C, an array of TC3 connectors 7D, and concrete reinforcing bars 2A and 2B.

[0075] 11A is a perspective view of a TC3 connector 11 with angled screws 11D. The connector is intended to penetrate a wood deck and connect to a wood beam (not shown) below. A steel top bar 1B is connected to a steel base plate 11A by structural welds 1C. The base plate 11A is secured to the wood substrate with adhesive (not shown) and angled / slanted self-tapping screws 11D. The holes for the screws 11D in the base plate 11A are preferably angled (i.e., not perpendicular) to the active surface of the base plate and may have a countersunk or similar shape to enhance adhesion with the screw heads.

[0076] 11B is a perspective view of a TC3 connector 33 in which the top bar is stamped, stamped, or expanded from the metal of the base plate. The steel top bar 3B is formed from the base plate 11B. The base plate 11B is connected to a wood substrate (not shown) with adhesive (not shown) and oblique / tilted self-tapping screws 11D. The holes for the screws 11D in the base plate 11B are preferably angled (i.e., not perpendicular) to the active surface of the base plate and may have a countersunk or similar shape for a tight fit with the screw head.

[0077] FIG. 11C is a perspective view of a TC3 connector 44, which is made by cutting and bending or folding a single metal plate to form the base plate and top bar. The steel top bar 4B and base plate 11C are formed from a single bent / folded plate with notches cut as described above. The base plate 11C is connected to a wood substrate (not shown) using adhesive (not shown) and oblique / tilted self-tapping screws 11D. The screw holes 11D in the base plate 11C are preferably slanted (i.e., not perpendicular) to the active surface of the base plate and may have countersunk or similar features for a tight fit with the screw heads.

[0078] Figure 12A is a front view of a TC3 connector 11 with angled screws 11D attached to the top of a CLT deck substrate 7A and threaded through to a timber beam 12 below. The TC3 connector 11 supports concrete reinforcing bars 2A and 2B. An optional sound insulating layer 7B is provided at the wood-to-concrete interface.

[0079] FIG. 12B is an exploded view of FIG. 12A.

[0080] FIG. 13 is a perspective view of a TC3 connector 11 in which an inclined screw 11D is attached to the upper surface of a CLT deck substrate 7A and is connected to a wooden beam 12 below.

[0081] FIG. 14 is an exploded view of FIG. 11, showing how a TC3 connector 11 with angled screws 11D is attached to the top surface of the CLT deck substrate 7A and through-connected to a timber beam 12 below.

[0082] FIG. 15 is an isometric view of a TC3 connector 11 installed along a timber beam 12 supporting a CLT deck 7A in an overall floor system.

[0083] Figure 16A is an elevation view showing mass timber panels 16A and 16B with prefabricated TC3 connections 1 stacked together for transport. The mass timber panels can be stacked in an alternating stacking fashion, with panel 16A in an upright position and panel 16B inverted on top of panel 16A. Additional shipping spacers 16C can be provided as needed. These nested groupings of CLT panels are transported by conventional methods such as flatbed semi-trailers or standard shipping container beds 16D.

[0084] FIG. 16B is an isometric view showing the TC3 connector 1 being utilized as a lifting attachment point for crane rigging 16E.

[0085] Figure 17 is a useful diagram for illustrating the truss forces within a module of a TC3 connector with ductile reinforcement supports. As shown, the horizontal shear force "V" is transferred between the concrete topping slab and the mass timber base material through strut-and-tie behavior. The horizontal shear force is primarily transferred through a diagonal compressive force "Fc" in the concrete slab surrounding and below the connector top bar. An opposing tensile force "Ft" occurs in the vertical leg of the connector top bar. The intentional weakness of this connection is the tensile strength of the vertical leg, and deflection of this member is desired to provide ductility to the system. In a TC3 connector with multiple modules in series, the overturning moment reactions "Rt" and "Rc" approximately cancel each other, except at the connector ends. The tension forces of the mechanical fasteners and the compressive forces of the mass timber panels resist the overturning demand at the connector ends.

[0086] Figure 18A shows the shear load demand "V" and shear deformation "D" at the wood-concrete interface. Figure 18B shows the shear load and deformation curves for a typical TCC connector and the predicted curve for a TC3 connector with ductile reinforcement bearings embodying the principles described herein. The vertical axis represents the shear-slip load demand at the interface between the wood board substrate and the concrete topping slab. The horizontal axis represents the shear-slip deformation of the TCC connector. Such curves have been well studied in structural beams and other applications.

[0087] As can be seen, the prior art TCC connector initially experiences a strain proportional to the shear load. This strain is considered elastic, and this stage is also clearly marked in Figure 18B. The prior art TCC connector then experiences nonlinear shear deformation as the load approaches the ultimate load (also clearly marked in Figure 18B). Then, as the shear load increases, the prior art connector ultimately fails.

[0088] In contrast, the expected behavior of a TC3 connector with a ductile stiffening support embodying the principles described herein is to remain in the initial elastic region of the curve at normal service level loads. A TC3 connector with a ductile stiffening support embodying the principles described herein deflects at the top bar stiffening support during an ultimate load event (i.e., the region between the normal service level and the ultimate level along the shear deformation axis) and experiences linear or substantially linear plastic deformation. Preferably, as shown in Figure 18B, the plastic deformation is constant or relatively constant (i.e., constant with shear load). Thus, in Figure 18B, the plastic deformation is shown as linear and constant. The deflection of the ductile top bar allows the TC3 connector to maintain load while sliding, operating along the plastic deformation region of the curve over a wide range of shear loads. This minimizes the design forces on the TC3 connector, allowing for fewer connectors to be used without compromising the performance of the composite structural system. Of course, with sufficient shear load, the TC3 connector will eventually fail, just like any other structural member.

Claims

1. a steel base plate that can be attached to a wood board substrate with adhesive and mechanical connectors, and that achieves a rigid connection when attached to the wood board substrate; a steel top bar integral with or fixed to said steel base plate and designed to deflect under ultimate load and undergo linear or substantially linear plastic deformation; A support formed on the steel top bar, which has the effect of supporting the reinforcing bar during pouring of fresh concrete; A wood-concrete composite connector comprising:

2. 10. The wood-concrete composite connector of claim 1, wherein the steel top bar is designed to deflect under ultimate load with a constant or virtually constant plastic deformation.

3. the top bar and the base plate are of one unitary construction; 2. The wood-concrete composite connector according to claim 1, wherein the top bar and the base plate are formed from the same steel plate by pressing, stamping, or expanding.

4. the top bar and the base plate are of one unitary construction; 2. The wood-concrete composite connector according to claim 1, wherein the top bar and the base plate are cut from the same steel plate and formed by bending or folding.

5. the top bar comprises deformed rebar, steel wire, or steel gauge metal; 2. The wood-concrete composite connector of claim 1, wherein the top bar is welded to the steel base plate.

6. 10. The wood-concrete composite connector of claim 1, wherein the base plate has a plurality of holes, each of which has a longitudinal axis that is not perpendicular to the effective plane of the base plate.

7. 10. The wood-concrete composite connector of claim 1, wherein the material of the base plate and the top bar is constructed from a reinforced composite material.

8. The wood-concrete composite connector of claim 1; a wooden board substrate to which the wood-concrete connector is fixed; Equipped with The wood-concrete composite structure is characterized in that the wood board substrate comprises cross-laminated board (CLT), glued laminated board panel (GLT), nail-laminated board (NLT), dowel-laminated board (DLT), laminated veneer board (LVL), mass plywood panel (MPP), glued laminated timber (Glulam), or parallel strand board (PSL).

9. 8. The wood-concrete composite structure of claim 7, wherein the wood board substrate comprises bamboo.

10. 9. The wood-concrete composite structure of claim 8, comprising a concrete slab in which the wood-concrete composite connector is embedded.

11. 9. The wood-concrete composite structure of claim 8, wherein the concrete topping slab comprises gypsum concrete.

12. 10. The wood-concrete composite structure of claim 8, including deformed rebar, welded wire mesh, post-tensioning cables, carbon fiber rods, fiberglass rods, or basalt rods supported by the top bar supports.

13. 9. The wood-concrete composite structure of claim 8, further comprising a sound-insulating layer between the wood board substrate and the concrete topping slab, the sound-insulating layer comprising a rubber mat, a fiber mat, or a foam sheet.

14. A method of forming the wood-concrete composite structure comprising: providing a wood-concrete composite connector according to claim 1; Adhering the wood-concrete composite connector to a wood board substrate; supporting rebar on the wood-concrete composite connector; pouring a concrete slab onto the wood board substrate and embedding the wood-concrete composite connector in the concrete slab; A method for providing

15. the top bar and the base plate are of one unitary construction; 15. The method of claim 14, wherein the top bar and the base plate are formed from the same steel sheet by pressing, stamping, or expanding.

16. the top bar and the base plate are of one unitary construction; 15. The method of claim 14, wherein the top bar and base plate are formed by cutting a steel plate and then bending or folding it.

17. the top bar comprises a deformed steel bar; 15. The method of claim 14, wherein the top bar is welded to the base plate.

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