A new type of wood structure bolt-steel infill panel joint structure and a design method thereof

Abstract

The present application belongs to the field of civil engineering and construction, and proposes a new type of wood structure bolt-steel infill panel joint structure and its design method. The joint structure comprises a first wood component (1), a second wood component (2), an arc hole infill steel plate (3), a fastening bolt (4) and a later stress bolt (5). In the joint structure, the arc hole infill steel plate is provided with a round hole and an arc hole. The fastening bolt in the round hole is first stressed and basically yielded in the early and middle stages, and the later stress bolt in the arc hole is gradually stressed in the large deformation stage, thereby improving the rotation capacity of the joint under large deformation. In the design method, first, the strength grade, specification, etc. of the arc hole infill steel plate and the bolt are determined according to relevant standards, then the parameters of the arc hole are determined, and finally the theoretical bending resistance of the joint is calculated. Compared with the prior art, the present application can significantly improve the bearing capacity and deformation capacity of the joint under large deformation, and the improvement rate is more than 50%, which is convenient for construction and promotion.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering, and in particular relates to a novel bolt-steel filler plate joint structure for timber structures and its design method. Background Technology

[0002] Heavy laminated timber frame structures (HFLACs) are highly prefabricated, with beam-column joints connected by bolts and steel fillers. They offer advantages such as simplicity, ease of installation, and clear force transmission, leading to their widespread use. However, timber structures may be subject to accidental forces such as earthquakes during their service life, potentially causing low-probability, high-loss structural collapses. Research indicates that the key to the collapse resistance of frame structures lies in the rotational capacity of beam-column joints under large deformations. However, when ordinary HFLAC beam-column bolt-steel filler joints are subjected to rotational forces, the timber in the joint area, due to its lower tensile strength across the grain and shear strength along the grain, is prone to brittle fractures such as splitting across the grain and shearing along the grain, resulting in poor joint rotational capacity.

[0003] Therefore, in order to ensure that the nodes have sufficient load-bearing capacity and deformation capacity, and to alleviate timber splitting damage in the node area, it is necessary to improve the rotation capacity of the nodes under large deformation through technical measures, thereby ensuring the collapse resistance of multi-story timber structures. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the existing technology and provide a new type of bolt-steel filler plate joint structure for wood structures and its design method.

[0005] This invention discloses a novel bolt-steel filler plate node structure for timber structures, comprising a first timber component, a second timber component, a filler plate with an arc-shaped hole, fastening bolts, and post-load-bearing bolts. The first and second timber components are placed perpendicularly and tightly against each other. A rectangular groove 1 is opened on the side of the first timber component, and a rectangular groove 2 corresponding to the rectangular groove 1 is opened on the cross section of the second timber component. The filler plate with the arc-shaped hole is placed in the rectangular groove 1 and the rectangular groove 2 on both sides, and the filler plate with the arc-shaped hole is connected to the first and second timber components to form an integral structure by fastening bolts and post-load-bearing bolts.

[0006] Furthermore, the first wooden component is provided with several screw holes, and one side of the steel plate with the arc-shaped hole is provided with several reserved screw holes that are consistent with the screw hole one. The fastening bolt includes a fastening bolt one, which passes through the screw hole one and the reserved screw hole one, thus fixing the first wooden component to the steel plate with the arc-shaped hole one.

[0007] Furthermore, the second wooden component is provided with several screw holes II and screw holes for later-loaded bolts; the other side of the steel plate with arc-shaped holes is provided with several reserved screw holes II consistent with the screw holes II, and at the same time, several arc-shaped holes corresponding to the center of the screw holes for later-loaded bolts are provided; the fastening bolts also include fastening bolts II, which pass through the screw holes II and the reserved screw holes II, and the later-loaded bolts pass through the screw holes for later-loaded bolts and the arc-shaped holes, thus fixing the second wooden component to the steel plate with arc-shaped holes.

[0008] The present invention discloses a novel design method for bolt-steel filler plate joints in timber structures, comprising the following steps: Step 1: Based on the seismic design requirements of the model structure or the actual engineering structure, determine the shear force design value Qd and the bending moment design value Md of the new glued laminated timber structure joints; Step 2: Determine the cross-sectional dimensions and material grades of the first and second wooden components, determine the strength grade and size specifications of the steel plate with the arc-shaped hole, and determine the strength grade, diameter, quantity, and arrangement of the fastening bolts and the later-loaded bolts. Step 3: Determine the moment when the node enters the large deformation stage: Based on the relative displacement δ of the structural failure member and its relationship with the relative rotation angle θ of the node, determine the relative displacement limit [δ] of the structural failure member. The moment when the node enters the large deformation stage is the stress stage after δ≥[δ]. Step 4: Based on the deformation requirements of the node during the large deformation stage, determine the curvature and width of the arc-shaped hole in the steel plate with the arc-shaped hole in the node structure. Step 5: Calculate the theoretical bending bearing capacity of the new type of wood structure bolt-steel filler plate joint.

[0009] Furthermore, in step one, if the design value of the shear force at the node is Qd=F, then the design value of the bending moment is Md=FH; Wherein, F is the concentrated load acting on the far end of the second wooden component (2), H is the distance of F from the node rotation center, and the node rotation center is the intersection of the edges of the first wooden component (1) and the second wooden component (2).

[0010] Furthermore, in step three, the relative displacement δ of the structurally failed component is defined as the vertical failure displacement. The ratio of h to the height h of the vertical member, θ is defined as the vertical failure displacement. The ratio of h to the span l of the horizontal component; therefore, their relationship is: The relative displacement limit [δ] of the structural failure member is determined based on the relative rotation angle limit [θ] of the node. The stress stage when δ ≥ [δ] is the large deformation stage of the node.

[0011] Furthermore, in step four, in order to facilitate rotational force during the large deformation stage, the width of the arc-shaped hole (33) is the same as or slightly larger than the diameter of the screw hole two (22) by 1~2 mm; according to the deformation requirements of the node during the large deformation stage of the model structure or the actual engineering structure, including the expected displacement and the expected rotation angle, the plastic rotation angle α to be increased by the node is determined by the relationship between δ and θ; since the node is subjected to reverse load due to accidental action such as earthquake, the arc of the arc-shaped hole (33) on the steel plate (3) with the arc-shaped hole is 2α.

[0012] Furthermore, in step five, calculating the theoretical flexural bearing capacity of the node under bending-shear coupling includes the following key points: (1) Calculation assumptions ① To simplify the calculation, the beneficial frictional effect between components is not considered, and the beneficial effect of beam-column compression on the bearing capacity is ignored; among them, the first wooden component (1) is a column, and the second wooden component (2) is a beam; ② The shear force generated by the bending moment in the node area for each bolt is proportional to the distance to the center of rotation of the node, and the direction is perpendicular to the line connecting the fastener and the center of rotation; ③ The shear force in the node area is borne and distributed equally by all bolts of the second wooden member (2) at the beam end, that is, the magnitude and direction of the shear force generated in each bolt are the same; ④ The bending moment resisted when the most dangerous bolt, i.e. the bolt with the greatest stress, yields or when the timber fails due to dowel bearing pressure is taken as the ultimate bending bearing capacity; (2) Composition of flexural bearing capacity of nodes The flexural bearing capacity of the joint area consists of two parts: one part is the flexural bearing capacity Ma provided by the fastening bolts during the early and middle stages of stress; the other part is the flexural bearing capacity Mb provided by the later-stage stressed bolts during the large deformation stage, i.e.: (3) Identify the two most dangerous types of bolts and calculate their resisting bending moments Ma and Mb respectively. During the early to mid-stages of stress formation, the fastening bolts primarily bear the load and provide resistance to the bending moment Ma. The second timber member rotates significantly relative to the first timber member; therefore, the center of rotation is taken as the intersection of the beam and column axes. The most critical fastening bolt, i.e., the bolt with the greatest stress, is the bolt p furthest away, and its resistance to bending moment is: During the large displacement stage of the node, the fastening bolts basically yield, and the later-stage stressed bolts mainly play a role in resisting the bending moment Mb. At this time, the squeezing phenomenon at the beam-column contact surface gradually intensifies. Therefore, the center of rotation of the node is taken as the junction of the beam-column contact surface. The most dangerous later-stage stressed bolt, i.e., the bolt with the greatest force, is the bolt q at the farthest point. Assuming that it has rotated to the limit position of the arc groove, its resisting bending moment is: In the formula, i, j, p, and q are bolt numbers, n and m are the number of fastening bolts and the number of bolts under later stress, respectively, ri is the distance from the fastening bolt to the rotation center, and rj is the distance from the bolt under later stress to the rotation center. (4) Shear force generated in each bolt In the formula, ha and hb are the distances from the loading point to the center of rotation of the fastening bolt and the later-loaded bolt, respectively; (5) Calculate the resultant force of the most dangerous fastening bolt and the most dangerous bolt under stress in the later stage. The most dangerous resultant force of the fastening bolt, Fa: The angle θa between Fa and the grain direction of the wood: Similarly, the most dangerous resultant force Fb of the bolts under stress in the later stage: The angle θb between Fb and the grain direction of the wood: (6) Calculate the standard values ​​of the shear bearing capacity of a single node under the oblique angles θa and θb respectively; Under the included angle θ of the diagonal lines, the standard value of the shear capacity Fk of a single shear surface at the node is calculated as follows: In the formula, FIs, FIIIs, and FIV are the shear capacity of the node under different failure modes, t1 is the thickness of the single shear plane of the wooden component, d is the bolt diameter, fh is the compressive strength of the timber pin bearing, and My is the yield moment of the bolt. The bending moment of the bolt yielding under bending can be calculated using the following formula: In the formula, fu is the ultimate tensile strength of the bolt, and d is the bolt diameter; The compressive strength fh of the wooden pin bearing is calculated using the following formula: In the formula, θ is the angle between the loading direction and the wood grain direction, d is the bolt diameter, ρ is the wood density, fh,0,i is the wood compressive strength along the grain, and k90 is the angle adjustment coefficient. (7) Calculate the theoretical flexural bearing capacity of the nodes. Since each bolt in the node has two shear surfaces, let the resultant force of the most dangerous fastening bolt Fa = 2Fk,a, and solve for Ma; let the resultant force of the most dangerous later-stage stressed bolt Fb = 2Fk,b, and solve for Mb, and then obtain the theoretical bending bearing capacity M of the new type of wood structure bolt-steel filler plate node.

[0013] Compared with the prior art, the present invention has the following advantages: 1) The relevant parameters of the arc groove on the inner steel plate can be calculated according to actual needs. Through this controllable design, the fastening bolts in the inner steel plate can be stressed first. After entering the large deformation stage, the fastening bolts will yield or break due to reaching the limit state. Then, the later-stage stressed bolts in the arc groove can rotate and be stressed gradually with the rotation of the second wooden component relative to the first wooden component, thereby avoiding or delaying the brittle failure of the glued laminated timber beam and improving the load-bearing capacity and deformation capacity of the joint.

[0014] 2) Compared with ordinary bolt-steel filler plate nodes, the present invention only adds arc-shaped holes to the inner filler steel plate, which is suitable for factory processing and easy to install on site; in addition, the additional post-load-bearing bolts are the same as the fastening bolts in the second wooden component, and the cost is controllable.

[0015] 3) This invention can significantly improve the plastic rotation angle of the second timber member relative to the first timber member under large deformation. The load-bearing capacity, deformation capacity, and energy dissipation capacity of the joint are all superior. Compared with ordinary bolt-steel filler plate joints, the improvement rate of bending load-bearing capacity and ultimate rotation angle can reach more than 50%. Applying it to glued laminated timber frames helps to improve the rotation capacity of the joint under large deformation, thereby improving the seismic performance and collapse resistance of the structure. At the same time, this joint does not change the appearance of ordinary bolt-steel filler plate joints, making it easy to promote and apply. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a novel bolt-steel filler plate joint structure for a wooden structure according to the present invention; Figure 2 yes Figure 1 A schematic diagram of the main view direction; Figure 3 yes Figure 2 AA sectional view; Figure 4 yes Figure 1 A front view schematic diagram of a steel plate filled with an arc-shaped hole; Figure 5 This refers to the geometric dimensions and structure in the main viewing direction of this embodiment of the invention; Figure 6 yes Figure 5 AA section view showing directional geometry and construction; Figure 7yes Figure 5 The geometric dimensions and structure of the steel plate with arc-shaped holes; Figure 8 A schematic diagram of nodal mechanics analysis according to an embodiment of the present invention.

[0017] in, 1-First wooden component; 11-Rectangular groove one; 12-Screw hole one; 2-Second wooden component; 21-Rectangular groove two; 22-Screw hole two; 23-Later load-bearing bolt screw hole; 3- Steel plate with arc-shaped hole; 31- Pre-drilled screw hole one; 32- Pre-drilled screw hole two; 33- Arc-shaped hole; 4-Fasting bolt; 41-Fasting bolt one; 42-Fasting bolt two; 5-Later stress bolts. Detailed Implementation

[0018] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0019] Example: The structure and design process of a novel bolt-steel filler plate joint for wood structures are as follows: Step 1: Based on the seismic design requirements of the model structure or the actual engineering structure, determine the shear force design value Qd and bending moment design value Md of the new glued laminated timber structure joint.

[0020] Given that the design value of the shear force at the node is Qd=F=70kN, the design value of the bending moment is Md=FH=44.45kN·m.

[0021] Where F is the concentrated load acting on the far end of the second wooden component 2, H is the distance of F from the rotation center of the node, and the intersection of the edge contact point of the first wooden component 1 and the second wooden component 2 is taken as the rotation center of the node, H=640mm; Step 2: Based on the "Standard for Design of Timber Structures" (GB5005-2017), relevant tests, and existing research results, determine the cross-sectional dimensions and material grades of the first timber component 1 and the second timber component 2, the strength grades, diameters, quantities, and bolt arrangements of the fastening bolts 4 and the later-loaded bolts 5, and the strength grades and dimensions of the steel plate 3 with arc-shaped holes.

[0022] (1) Determine the relevant parameters of the timber components according to the "Standard for Design of Timber Structures" (GB5005-2017) and related studies: The first timber component 1 (column) and the second timber component 2 (beam) in the node specimens are both made of Douglas fir glued laminated timber with a strength grade of TCT32. The measured moisture content is 11.6%, the density is 481 kg / m3, the cross-sectional dimensions are 325 mm × 325 mm and 175 mm × 350 mm respectively, and the length of both is 1000 mm.

[0023] (2) Determine the bolt-related parameters according to the "Standard for Design of Timber Structures" (GB5005-2017): like Figure 5 , Figure 6 As shown, fastening bolt 41 is an 8.8 grade high-strength bolt with a diameter d=20mm. There are a total of 6 fastening bolts 41, arranged in three rows and two columns. The row spacing of the bolt group is 80mm, and the end distance between the edge bolt of the row and the first wooden component 1 is 420mm. The column spacing is 145mm, and the end distance between the center of the column edge and the first wooden component 1 is 90mm.

[0024] Fastening bolt 42 is a grade 8.8 high-strength bolt with a diameter of d=12mm. There are a total of 6 fastening bolts 42, which are arranged in three rows and two columns. The row spacing of the bolt group is 75mm, and the end distance between the bolt at the edge of the row and the second wooden component 2 is 100mm. The column spacing is 240mm, and the distance between the center of the column edge and the edge of the first wooden component 1 is 120mm.

[0025] The fifth bolt, which bears the load in the later stage, is a high-strength bolt of grade 8.8 with a diameter d=12mm.

[0026] To facilitate installation, the diameters of screw hole 12 of the first wooden component 1 and screw hole 22 of the second wooden component 2 are both increased by 2mm compared to the bolt diameter, namely 22mm and 14mm respectively.

[0027] (3) Based on the existing relevant parameters, determine the material, size, aperture and other parameters of the steel filler plate. like Figure 7 As shown, the steel plate 3 with arc-shaped hole has a strength grade of Q345B, a size of 350mm×765mm, and a thickness of 9.5mm. The diameters of the reserved screw holes 1 and 2 are the same as the diameters of screw holes 1 and 2, which are 22mm and 14mm respectively.

[0028] Step 3: Determine the relative displacement limit [δ] of the structural failure component, and then define the node as entering the large deformation stage.

[0029] Existing research indicates that the peak load corresponding to θ for ordinary beam-column bolt-steel filler plate joints is 0.12 rad to 0.17 rad. After this, the increase in θ decreases and the bearing capacity declines. During subsequent stress processes, insufficient rotational capacity of the joint increases the probability of glued laminated timber frame collapse. This invention aims to improve the rotational capacity of ordinary joints under large deformation. However, in actual engineering, heavy glued laminated timber frame structures are often equipped with floor slabs. When the structure collapses, the floor slabs will generate a membrane effect. Considering structural safety, the relative rotation angle limit [θ] of the joint is set to a lower limit of 12%, corresponding to the relative displacement limit [δ] of the structural failure component = 12%l / h. Therefore, the stress stage where δ ≥ [δ] is the stage of large deformation of the joint.

[0030] Referring to the "Standard for Design of Timber Structures" (GB5005-2017) and related tests, the cross-sectional dimensions of the glued laminated timber beams and columns in the model structure from which the nodes are taken are 175mm×350mm and 325mm×325mm, respectively. The column height h is taken as 3.30m, and the beam span l is taken as 5.25m. Therefore, the relative displacement limit of the structural failure member [δ]≈19%, and the large deformation stage of the node is the stress stage where δ≥19%. Step 4: Determine the curvature and width of the arc-shaped hole 33 on the steel plate 3 with the arc-shaped hole described in the node.

[0031] like Figure 5 As shown, the distance between the center of the arc-shaped hole and the second wooden component 2 is 50mm. To facilitate the rotation of the bolt under force, the width of the arc-shaped groove is 14mm, which is 2mm larger than the diameter of the later-loaded bolt 5.

[0032] When δ≥19%, the node begins to enter the large deformation stage, and the rotation angle of the second wooden component relative to the first wooden component is approximately 0.15 rad. In this embodiment, the maximum design rotation angle is expected to increase by approximately 50%, corresponding to an increase of 0.08 rad in the node rotation angle. Considering that the node may be subjected to positive and negative loads due to accidental actions such as earthquakes, and taking into account the cumulative effect of node damage, it is proposed to increase the plastic rotation angle α=0.12 rad, so the radian of the arc hole 33 2α=0.24 rad.

[0033] Steps two through four above determine the geometric dimensions of the novel timber structure bolt-steel filler plate node, as follows: Figure 5 , Figure 6 and Figure 7 As shown.

[0034] Step 5: Based on the "Standard for Design of Timber Structures" (GB5005-2017), the European standard EN1995-1-1, and existing research results, calculate the theoretical bending capacity of a novel bolt-steel filler plate joint in timber structures. The stress analysis diagram of the joint is shown below. Figure 8 As shown.

[0035] The most dangerous fastening bolt is bolt ③, which is furthest away. The resultant force Fa under the bending-shear coupling action is: The angle θa between Fa and the grain direction of the wood is: x3=523 mm, y3=75 mm, ∑ri2=1083354 mm2, n=6, ha=803 mm Substituting, we get: Fa2 = 4.81328 × 10⁻⁷ × Ma2 θa = 1.47 rad The most dangerous bolt subjected to stress in the later stages is the bolt furthest away (⑧). The resultant force Fb under the coupled bending and shear action is: The angle θb between Fb and the grain direction of the wood is: x8=375 mm, y8=284 mm, ∑rj2=464402 mm2, m=4, hb=640 mm Substituting, Fb2 = 1.80946 × 10⁻⁶ × Mb2 θb = 1.10 rad Calculate the standard values ​​of Fk,a and Fk,b of the shear capacity of a single node under the bias angles θa and θb. The bending moment at which the bolt yields under bending is: The compressive strength fh of the wooden pin bearing is: When θa = 1.47 rad, d = 12 mm, ρ = 481 kg / m3, substituting these values ​​into fh, we get a = 24.22 MPa; When θb = 1.10 rad, d = 12 mm, ρ = 481 kg / m3, substituting these values ​​into fh, we get b = 24.44 MPa; Substituting the above fh, a, fh, b, and My into the following formula Where t1=82 mm, d=12 mm, substituting these values, we obtain the standard values ​​Fk of the single shear capacity under θa and θb as follows: Fk,a=min{22400N,11823N,14893N}=11823 N Fk,b=min{24044N,12511N,15430N}=12511 N Let the resultant force of the most dangerous fastening bolt Fa=2Fk,a=23647N, then we can get Ma=34.08 kN·m; Let the resultant force of the bolt under the most dangerous later stage of stress be Fb=2Fk,b=25022N, then we can get Mb=18.60 kN·m; The bending bearing capacity of the node is M = Ma + Mb = 52.68 kN·m > Md = 44.45 kN·m, which meets the bearing capacity design requirements.

[0036] Existing tests have demonstrated that the flexural bearing capacity, ultimate rotation angle, and cumulative energy dissipation capacity of the timber structure joint with additional post-load-bearing bolts provided in this embodiment of the invention are improved by 53%, 60%, and 116%, respectively, compared to the ordinary bolt-steel filler plate joint. Furthermore, the experimental value of the flexural bearing capacity of this joint is 56.93 kN·m, while the theoretical flexural bearing capacity value provided by this invention is 52.68 kN·m, representing 92.5% of the experimental value, indicating that the theoretical calculation method is reasonable.

[0037] The above description is merely a description of preferred embodiments of this application and is not intended to limit the scope of this application in any way. Any changes or modifications made by those skilled in the art based on the above-disclosed technical content should be considered as equivalent and valid embodiments, and all fall within the scope of protection of the technical solution of this application.

Claims

1. A novel bolt-steel filler plate joint structure for wooden structures, characterized in that, It includes a first wooden component (1), a second wooden component (2), a steel plate with an arc-shaped hole (3), fastening bolts (4), and a later-load-bearing bolt (5); The first wooden component (1) and the second wooden component (2) are placed vertically and close together. The first wooden component (1) has a rectangular groove (11) on its side. The second wooden component (2) has a rectangular groove (21) on its cross section that corresponds to the rectangular groove (11). The steel plate (3) with arc-shaped hole is placed in the rectangular groove (11) and the rectangular groove (21) on both sides respectively. The steel plate (3) with arc-shaped hole is connected to the first wooden component (1) and the second wooden component (2) into an integral structure by fastening bolts (4) and later load-bearing bolts (5). The second wooden component (2) is provided with several screw holes (22) and screw holes (23) for later load-bearing bolts, both of which are round holes; the other side of the steel plate (3) with arc-shaped holes is provided with several reserved screw holes (32) consistent with the screw holes (22), and at the same time, it is provided with several arc-shaped holes (33) corresponding to the center of the screw holes (23) for later load-bearing bolts; the fastening bolt (4) also includes a fastening bolt (42), the fastening bolt (42) passes through the screw holes (22) and the reserved screw holes (32), and the later load-bearing bolt (5) passes through the screw holes (23) for later load-bearing bolts and the arc-shaped holes (33), thus fixing the second wooden component (2) and the steel plate (3) with arc-shaped holes in place; The width of the arc-shaped hole (33) is the same as or 1-2 mm larger than the diameter of the screw hole (22). The plastic rotation angle α of the node is determined by the relationship between the relative displacement δ of the structural failure component and the angle θ of the diagonal thread. The arc of the arc-shaped hole (33) on the steel plate (3) with the arc-shaped hole is 2α. Calculate the theoretical flexural bearing capacity M of the node under bending-shear coupling: The flexural bearing capacity of the joint area consists of two parts: one part is the flexural bearing capacity Ma provided by the fastening bolts during the early and middle stages of stress; the other part is the flexural bearing capacity Mb provided by the later-stage stressed bolts during the large deformation stage. ; Identify the two most dangerous types of bolts and calculate their resisting bending moments Ma and Mb respectively. During the early to mid-stage of stress, the fastening bolts provide resistance to bending moment Ma. The second wooden component (2) rotates significantly relative to the first wooden component (1). The most dangerous fastening bolt, i.e., the bolt with the greatest stress, is the bolt p furthest away, and its resistance to bending moment is: During the large displacement stage at the node, the fastening bolts basically yield, and the later-stage stressed bolts play a role in providing resistance to the bending moment Mb. The most dangerous later-stage stressed bolt, i.e., the bolt with the greatest stress, is the bolt q furthest away, and its resistance to bending moment is: In the formula, i, j, p, and q are all bolt numbers, n and m are the number of fastening bolts and the number of bolts under later stress, respectively, ri is the distance from the fastening bolt to the rotation center, and rj is the distance from the bolt under later stress to the rotation center. Shear force generated in each bolt In the formula, ha and hb are the distances from the loading point to the center of rotation of the fastening bolt and the later-loaded bolt, respectively; Calculate the resultant force of the most critical fastening bolt and the most critical bolt subjected to stress in the later stages of the process. The most dangerous resultant force of the fastening bolt, Fa: The angle θa between Fa and the grain direction of the wood: Similarly, the most dangerous resultant force Fb of the bolts under stress in the later stage: The angle θb between Fb and the grain direction of the wood: Calculate the standard values ​​of the shear capacity of a single node, Fk,a and Fk,b, respectively, under the included angles of the diagonal stripes θa and θb. Under the included angle θ of the diagonal lines, the standard value of the shear capacity Fk of a single shear surface at the node is calculated as follows: In the formula, FIs, FIIIs, and FIV are the shear capacity of the node under different failure modes, t1 is the thickness of the single shear plane of the wooden component, d is the bolt diameter, fh is the compressive strength of the timber pin bearing, and My is the yield moment of the bolt. The bending moment of the bolt yielding under bending is calculated using the following formula: In the formula, fu is the ultimate tensile strength of the bolt, and d is the bolt diameter; The compressive strength fh of the wooden pin bearing is calculated using the following formula: In the formula, θ is the angle between the loading direction and the wood grain direction, d is the bolt diameter, ρ is the wood density, fh,0,i is the wood compressive strength along the grain, and k90 is the angle adjustment coefficient. The resultant force of the most dangerous fastening bolt Fa = 2Fk,a, which gives Ma; the resultant force of the most dangerous bolt under later stress Fb = 2Fk,b, which gives Mb, and thus the theoretical bending bearing capacity M is obtained.

2. The novel bolt-steel filler plate joint structure for wooden structures according to claim 1, characterized in that, The first wooden component (1) is provided with several screw holes (12), and the steel plate (3) with arc-shaped hole is provided with several reserved screw holes (31) on one side that are consistent with the screw holes (12). The fastening bolt (4) includes a fastening bolt (41), which passes through the screw holes (12) and the reserved screw holes (31), thus fixing the first wooden component (1) and the steel plate (3) with arc-shaped hole to each other.

3. A method for designing the novel bolt-steel filler plate joint structure for wooden structures as described in claim 1, characterized in that, Includes the following steps: Step 1: Based on the seismic design requirements of the model structure or the actual engineering structure, determine the shear force design value Qd and the bending moment design value Md of the new glued laminated timber structure joints; Step 2: Determine the cross-sectional dimensions and material grades of the first wooden component (1) and the second wooden component (2), determine the strength grade and size specifications of the steel plate (3) with arc-shaped hole filling, and determine the strength grade, diameter, quantity and bolt arrangement of the fastening bolt (4) and the later-loaded bolt (5). Step 3: Determine the moment when the node enters the large deformation stage: Based on the relative displacement δ of the structural failure member and its relationship with the relative rotation angle θ of the node, determine the relative displacement limit [δ] of the structural failure member. The moment when the node enters the large deformation stage is the stress stage after δ≥[δ]. Step 4: Based on the deformation requirements of the node during the large deformation stage, determine the curvature and width of the arc-shaped hole (33) on the steel plate (3) with arc-shaped hole in the node structure; Step 5: Calculate the theoretical bending bearing capacity of the bolt-steel filler plate joint of the new type of wood structure under bending-shear coupling.

4. The method according to claim 3, characterized in that, In step one, If the design value of the shear force at the node is Qd=F, then the design value of the bending moment is Md=FH; Wherein, F is the concentrated load acting on the far end of the second wooden component (2), H is the distance of F from the node rotation center, and the node rotation center is the intersection of the edges of the first wooden component (1) and the second wooden component (2).

5. The method according to claim 3, characterized in that, In step three The relative displacement δ of a structurally failing component is defined as the vertical failure displacement. The ratio of h to the height h of the vertical member, θ is defined as the vertical failure displacement. The ratio of h to the span l of the horizontal component; therefore, their relationship is: The relative displacement limit [δ] of the structural failure member is determined based on the relative rotation angle limit [θ] of the node. The stress stage when δ ≥ [δ] is the large deformation stage of the node.

6. The method according to claim 3, characterized in that, In step four, To facilitate rotational force during the large deformation stage, the width of the arc hole (33) is the same as or 1-2 mm larger than the diameter of the screw hole (22); based on the deformation requirements of the node during the large deformation stage of the model structure or the actual engineering structure, including the expected displacement and expected rotation angle, the plastic rotation angle α to be increased at the node is determined by the relationship between δ and θ. Because the node is subjected to a reverse load due to an accidental action, the arc of the arc hole (33) on the steel plate (3) with the arc hole is 2α.

7. The method according to claim 3, characterized in that, In step five, the theoretical flexural bearing capacity of the node under bending-shear coupling is calculated, including: (1) Calculation assumptions ① To simplify the calculation, the beneficial frictional effect between components is not considered, and the beneficial effect of beam-column compression on the bearing capacity is ignored; among them, the first wooden component (1) is a column, and the second wooden component (2) is a beam; ② The shear force generated by the bending moment in the node area for each bolt is proportional to the distance to the center of rotation of the node, and the direction is perpendicular to the line connecting the fastener and the center of rotation; ③ The shear force in the node area is borne and distributed equally by all bolts of the second wooden member (2) at the beam end, that is, the magnitude and direction of the shear force generated in each bolt are the same; ④ The bending moment resisted when the most dangerous bolt, i.e. the bolt with the greatest stress, yields or when the timber fails due to dowel bearing pressure is taken as the ultimate bending bearing capacity; (2) Composition of flexural bearing capacity of nodes The flexural bearing capacity of the joint area consists of two parts: one part is the flexural bearing capacity Ma provided by the fastening bolts during the early and middle stages of stress; the other part is the flexural bearing capacity Mb provided by the later-stage stressed bolts during the large deformation stage, i.e.: (3) Identify the two most dangerous types of bolts and calculate their resisting bending moments Ma and Mb respectively. During the early to mid-stage of stress formation, the fastening bolts primarily bear the load and provide resistance to the bending moment Ma. The second wooden component (2) rotates significantly relative to the first wooden component (1), so the center of rotation is taken as the intersection of the beam and column axes. The most dangerous fastening bolt, i.e., the bolt with the greatest stress, is the bolt p furthest away, and its resistance to bending moment is: During the large displacement stage of the node, the fastening bolts basically yield, and the later-stage stressed bolts mainly play a role in resisting the bending moment Mb. At this time, the squeezing phenomenon at the beam-column contact surface gradually intensifies. Therefore, the center of rotation of the node is taken as the junction of the beam-column contact surface. The most dangerous later-stage stressed bolt, i.e., the bolt with the greatest force, is the bolt q at the farthest point. Assuming that it has rotated to the limit position of the arc groove, its resisting bending moment is: In the formula, i, j, p, and q are all bolt numbers, n and m are the number of fastening bolts and the number of bolts under later stress, respectively, ri is the distance from the fastening bolt to the rotation center, and rj is the distance from the bolt under later stress to the rotation center. (4) Shear force generated in each bolt In the formula, ha and hb are the distances from the loading point to the center of rotation of the fastening bolt and the later-loaded bolt, respectively; (5) Calculate the resultant force of the most dangerous fastening bolt and the most dangerous bolt under stress in the later stage. The most dangerous resultant force of the fastening bolt, Fa: The angle θa between Fa and the grain direction of the wood: Similarly, the most dangerous resultant force Fb of the bolts under stress in the later stage: The angle θb between Fb and the grain direction of the wood: (6) Calculate the standard values ​​of the shear bearing capacity of a single node under the oblique angles θa and θb respectively; Under the included angle θ of the diagonal lines, the standard value of the shear capacity Fk of a single shear surface at the node is calculated as follows: In the formula, FIs, FIIIs, and FIV are the shear capacity of the node under different failure modes, t1 is the thickness of the single shear plane of the wooden component, d is the bolt diameter, fh is the compressive strength of the timber pin bearing, and My is the yield moment of the bolt. The bending moment of the bolt yielding under bending is calculated using the following formula: In the formula, fu is the ultimate tensile strength of the bolt, and d is the bolt diameter; The compressive strength fh of the wooden pin bearing is calculated using the following formula: In the formula, θ is the angle between the loading direction and the wood grain direction, d is the bolt diameter, ρ is the wood density, fh,0,i is the wood compressive strength along the grain, and k90 is the angle adjustment coefficient. (7) Calculate the theoretical flexural bearing capacity of the nodes. Since each bolt in the node has two shear surfaces, let the resultant force of the most dangerous fastening bolt Fa = 2Fk,a, and solve for Ma; let the resultant force of the most dangerous later-stage stressed bolt Fb = 2Fk,b, and solve for Mb, and then obtain the theoretical bending bearing capacity M of the new type of wood structure bolt-steel filler plate node.

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