JP5071915B2 - Joining bracket and joining method for wooden column beam members - Google Patents

Description

  The present invention relates to a method for joining wooden members, in which pre-stress is generated at a joint portion of a wooden structure member, in particular, a column and a beam constituting a ramen, and joined to each other, and a joint fitting suitably used in this method.

  There are great expectations for wooden ramen, and many studies have been made on moment resistance joining of column-to-beam joints (hereinafter simply referred to as “joints”), and various joining methods have been proposed (non-patent documents, etc.).

Architectural Institute of Japan, “Wood Structure Design Notes”, P184-P221, 1996

However, in the practical range, it is difficult to make the joint strength close to the strength of the base material, and the proportion of deformation of the joint to the total deformation of the frame becomes large. Complicated calculations of stress and deformation.
The present inventors have studied a method of tensile joining that effectively brings the bending strength of the joint between the members close to the reference bending strength of the base material, and demonstrated the reinforcement effect in a fracture test of the bending shear force of the member. ing.

  An object of the present invention is to increase the rotational rigidity and proof stress of the joint by introducing a large prestress to the joint using the method, and to bring the joint closer to a rigid joint.

  The metal column beam member joint metal fitting according to the present invention is a metal fitting for joining both members to each other at a joint part including a column and a beam constituting a wooden structure, and is fixed in the column along the beam direction. A pressure receiving member and a fastening member extending through the column along the beam direction and extending into the beam, and prestress is introduced into the pressure receiving member by tightening the fastening member. It is characterized by that.

  Further, a method for joining wooden column beam members according to the present invention is a joining method in which both members are joined to each other in a joint portion including a column and a beam constituting a wooden structure, and a pressure receiving member is provided inside the joint portion of the pillar. Prestress is introduced into the pressure receiving member by fixing and tightening a fastening member penetrating the column along the beam direction.

According to the present invention, the horizontal rigidity and horizontal strength of the wooden frame are typically increased. Further, in the calculation of stress / deformation, the joint can be calculated as a rigid joint, which can be performed very simply and accurately.
Specifically, it was possible to calculate the stress and deformation of the ramen as rigid joints up to 70% of the horizontal strength of the frame layer. The degree of rigid joint at the joint is improved to the same level as the RC frame.
In addition, by introducing prestress, the rotational rigidity of the joint is increased, and for example, it is effective up to a moment of about 60% of the standard bending strength of the base material of the beam.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a joining member and joining method for wooden column beam members according to the present invention will be described based on the drawings.
Bonding method and stress transmission Here, first of bonding method according to the present invention (hereinafter, referred to as the present joining method) describes how the transmission of stresses in the.
The joining method of the present invention is shown in FIG. Assuming the application of solid ramen, the method of assembling the pillar 1 and the beam 2 is the pillar win.

  Tensile bonding is an improvement of the conventional method of tension bolt bonding. As shown in FIG. 2, a deep long groove 4 is added to the square hole 3 of the beam 2, and a metal object 5 (hereinafter referred to as a U-shaped metal object) obtained by bending a flat steel into a U-shape is bonded thereto with an adhesive 6. The U-shaped metal piece 5 has a bolt hole 5a at the bottom, and the leg portion 5b is shear bonded to the base material (beam 2). Since the leg portion 5b is a flat steel, the ratio of the side adhesive surface to the cross section of the tensile shaft is extremely large, and the adhesion area can be easily secured even if the length of the leg portion 5b is short. As will be described later, reinforcing bars are inserted into the joints to prevent penetration and introduce prestress, and are fixed with an adhesive.

  As shown in FIG. 1B, the joining is performed by inserting a PC bar 7 (fastening member) into the column 1 and assembling the beam 2 and tightening the nut 8 to introduce prestress. A square washer 9 is attached between the nut 8 and the bottom of the U-shaped hardware 5. Since this joining method can be dismantled by removing the nut 8 without deteriorating the mechanical performance of the frame, it is easy to relocate the building and reuse the members. It is also possible to yield the PC bar 7 in the event of a large earthquake, retighten the nuts after the earthquake, restore the earthquake resistance to the initial state, and restore the residual deformation of the building. In this joining method, a large prestress is positively introduced, and the PC bar 7 is yielded to clearly secure an energy absorption amount in a large deformation region.

Next, internal force transmission and mechanical effects at the joint will be described.
A boundary surface between the joint and the beam 2 (hereinafter referred to as a beam end surface) serves as a separation surface of the member, and it is necessary to reinforce this surface. FIG. 3 shows a schematic diagram of internal force transmission.
Bending tension _p T is to transmit to the bending tensile range of the base material via the PC steel bars and the U-shaped fittings as shown in FIG. 3 (a). Since the PC bar is not fixed in the joint, it is attracted by the left and right beams. The bending compression force is transmitted to the bending compression area of the base material by the base material remaining portion other than the square hole and the U-shaped metal part on the beam side. At the joint, as shown in FIG. 3B, the bending compressive force of the beam is received by the reinforcing bar 11 (pressure receiving member) that is fixed via the square washer 10, and is balanced with the shearing force of the column via the adhesive.

In this example, as shown in FIG. 1 or FIG. 5 or the like, four reinforcing bars 11 are used and inserted into the through hole 12 of the column 1. The square washer 10 is formed with a through hole 13 through which the PC bar 7 is inserted.
In addition, three tenons 14 are provided on the end face of the beam 2, and tenon holes 15 for fitting with the tenons 14 are formed on both side faces of the column 1. As shown in FIG. 5, the square washer 10 is formed with a through hole 16 through which the PC bar 7 is inserted.

  The shearing force of the beam is transmitted by the frictional force of the tenon provided on the beam end face and the bending compression region of the beam end face. In this joining method, since prestress is introduced, the cross section of the beam is entirely compressed, the frictional force is large from the initial load stage, and shear slip does not occur.

  The rotational rigidity of the beam end face of the joint is determined by the axial rigidity in the horizontal direction in the joint if the beam end face is in a fully compressed state due to prestress even when a moment is received from the beam. Large rotational rigidity is exhibited by adjusting the amount of reinforcing bars to be fixed there. According to the present joining method, the rotational rigidity and bending strength of the joint are increased by these, and the bending strength close to the reference bending strength of the base material is exerted on the beam.

Outline of Experiment A specimen used in the present invention will be described.
4 and 5 show the shape and dimensions of the test specimen. It is a cruciform frame with pillars and beams cut at the inflection points, and the scale is about 2/3 of the actual size. In this embodiment, there are two specimens. No. As shown in FIG. 2 (a), one test body is provided with only a tensile joint metal. The rigidity and proof stress are determined by the penetration of the joint. It is a comparative test body of 2 test bodies.

No. In the two specimens, a high-strength reinforcing bar (4-D13) for preventing penetration was fixed to the joint with an adhesive, and a square washer was adhered to the beam end surface on the beam side with an adhesive. Sufficient reinforcement was provided against penetration. The adhesive used was an epoxy system. For the columns and beams, different grades of symmetric laminated G65-F225 were used. The material of the hardware and the washer was SS400, and the U-shaped hardware was obtained by cold-bending flat steel. The bending tension side is No. Before the base material of the beam was bent and tensile-fractured in two specimens, the PC bar was designed to exhibit ductile bending properties by tensile yielding. Against bending tensile strength _w T _By the matrix area can be transmitted at a U-shaped hardware ^{(50 × 105mm 2) (=} 116.6kN), the yield strength _p T _y of PC steel bar one was 90 kN. _p T _y is a strength to surrender in the thread.

  FIG. 6 shows a method of applying force and a measurement state of bending shear deformation of a beam and a column. 6 and 7 show a schematic configuration of the measuring apparatus 100 in this embodiment. In the figure, 101 is a support pin, 102 is an oil jack, 103 is a load cell for load measurement, 104 is a pin, 105 is a vertical roller, 106 is a universal pin, and 107, 107A and 107B are displacement meters.

  The column head and column base were supported by pins, and repeated vertical loads were applied to the ends of the left and right beams. The maximum deformation angle of the beam in each force cycle is 1/600, 1/300, 1/200, 1/150, 1/100, 1/50, 1/40, 3/100, 4/100, 5/100 rad. . It was gradually increased in this order. FIG. 7 shows the measurement status of the deformation of the joint. The rotation angle of the beam end face was measured with the displacement meter A, and the indentation deformation of the joint was measured with the displacement meter B.

The introduction of pre-stress to the PC steel bars is carried out by tightening the nut, from the torque value of tightening, it was converted to its original tension T _o. For the conversion, the result of the torque-tension test of PC bar steel separately performed was used. No. Original tension T _o of 1 specimen is 10 kN, the ratio of yield strength _p T _y (hereinafter, referred to as T _o / _p T _y) was 0.11. No. In 2 specimens at the stage of initial force application, by changing the T _o / _p T _y into three levels 0.33,0.44,0.94 performs pressurizing force of 1 cycle at each stage, beam end face The rotational rigidity of was investigated.

Experimental Results Next, the fracture state and the relationship between the layer shear force and the interlayer deformation angle will be described.
FIG. 8 shows the relationship between the layer shear force and the interlayer deformation angle. The laminar shear force was calculated from the balance between the vertical load at the ends of the left and right beams and the moment of the horizontal reaction force between the upper and lower columns. The interlaminar deformation angle R was determined by adding the deformation component due to the beam to the bending shear deformation of the column. Interlayer deformation that occurs when the beam tip moves horizontally according to the actual deformation state of the frame. The layer height H is 2034 mm. No. 2 test body is the relationship later was 0.94 T _o / _p T _y. No. of FIG. No. 2 in the specimen. The envelope of one specimen is also indicated by a broken line.

  No. One specimen had a bending compression zone on the beam side of the beam end face in the joint, yielded, and the subsequent stiffness was determined. No destruction other than penetration occurred. Due to the introduction of prestress, no initial slip occurred. No. No. 2 in the test body. The indentation deformation to the joint part which arose in 1 test body was not confirmed at all visually. The QR relationship is macroscopically linear up to about 90% of the maximum yield strength. After that, the prestress effect of the left and right beams disappears, the rigidity decreases, and R is about ± 1/50 rad. The maximum proof strength has been reached.

Next, each deformation component and the degree of rigid joint in interlayer deformation will be described.
Interlayer deformation is divided into deformation components of columns, beams and joints. FIG. 9 shows the relationship between the layer shear force and each deformation component. The horizontal axis represents the deformation angle and is indicated by an envelope.
In FIG. 9, − ● − is the entire interlayer deformation angle R. The broken line is the deformation angle component of the column, and the dotted line is the sum of the deformation angle component of the beam. The difference in deformation angle between the dotted line and − ● − is an interlayer deformation angle component due to deformation of the joint. The inter-layer deformation angle component due to the joint depends on the rotation angle of the beam end face by the displacement meter A (or FIG. 15) in FIG. The rotation angle is divided into a component due to bending compression deformation and a component due to bending tensile deformation. The former is mainly due to penetration of the joint, and the latter is mainly due to pulling out due to elongation of the PC bar. A thick solid line is obtained by adding an interlayer deformation angle component due to bending tensile deformation to the dotted deformation angle. When − ● − and the thick solid line coincide with each other, it can be determined that no indentation deformation of the joint portion occurs.

No. One specimen has an overall interlayer deformation angle R of 1/100 rad. The rate of deformation of the column is 4.2%, the beam is 13.1%, the bending tensile deformation of the joint is 49.0%, and the bending compressive deformation of the joint is 33.7%. As a department, it accounted for 82.7% of the total.
No. 2 specimens have an R of 1/100 rad. The rate of deformation of the column is 34.3%, the beam is 52.5%, the bending tensile deformation of the joint is 8.2%, and the bending compressive deformation of the joint is 5.0%. Deformation was negligible, and the joint was only 13.2% of the total.

  FIG. 11 shows a comparison between the relationship of the elastic stiffness calculated by the beam theory and the experimental result by providing a rigid zone in the joint with the column and the beam as a rigid joint. As shown in FIG. 10, calculation I is a relationship in which all the joints are rigid regions, calculation II is a relationship in which no rigid region is provided, and calculation III is to a castle that is often used in reinforced concrete structures (hereinafter referred to as RC). The distance is set to 1/4 of the member D. The base value of the base material was used for the Young's modulus of columns and beams.

  No. One specimen is much less rigid than Calculation II, and it can be confirmed that it is impossible to calculate the stress and deformation of the frame as a rigid frame. On the other hand, no. Two specimens can be estimated by calculation III up to 70% of the maximum yield strength. The deformation angle is 1/120 rad. Of 1/120 rad. Within this range, it is possible to calculate stress and deformation as rigid ramen. Therefore, the same degree of rigid joint as that of the RC frame is realized at the joint by this joining method.

Next, the behavior of the joint and the beam will be described.
Here, the rigidity and proof stress of the joint will be described using m and θ. First, in relation to the definitions of m and θ, the ratio (M _B ) of the bending moment M _B of the beam end face (boundary surface between the joint and the beam) to the reference bending strength M _fb of the beam base material shown in the equation (1). / M _fb ) is m. M _B is a value obtained by multiplying the distance (1070 mm) to beam end to vertical load beam tip.
M _fb = Z · F _b (1)
Here, Z: section modulus of beam base material, F _b : bending bending strength of wood (= 22.2 N / mm ² ).

In the rigid frame, the degree of rigid joint at the joint is expressed by the angle of the beam end face with respect to the column axis in the joint. This angle is defined as the rotation angle θ of the beam end face. Here, the rotation angle calculated from the deformation amount of the displacement meter A shown in FIGS. 7 and 15 was used. The rotation angle includes deformation in the joint and partial beam deformation in the vicinity of the end face of the beam (section L ₂ in FIG. 15).

With regard to the prestress effect that contributes to the rotational rigidity of the beam end face, the prestress was changed in stages. FIG. 12 shows the m-θ relationship between the beam end faces of the two specimens. Right side shows the auxiliary shaft of the absolute value of the moment, and T _o / _p T _y, are employed as the subtitle of FIG. The point at which the stiffness rapidly decreases is indicated by a circle. This is the point when the pre-stress effect disappears. This is because the rebar in the joint that has been compressed due to pre-stress changes to a tensile state due to the moment of the beam and does not resist.

In the figure, the moment _{Mo at} which the prestress effect disappears is indicated by a horizontal alternate long and short dash line. This is based on the method described later. It can be confirmed that by increasing the pre-stress original tension T _o , the range of moments for which high rigidity can be expected increases. In the figure, no. The envelope of one test body is indicated by a dotted line. Comparing the rigidity rotation angle when T _o / _p T _y is the pre-stress effect disappears at 0.94, No. 2 Specimen No. The effectiveness of this joining method could be confirmed at 13 times that of one specimen.

Regarding the moment-rotation angle relationship of the beam end face, FIG. 13 shows the m-θ relationship. No. 2 test is relationship 0.94 prestressing ratio T _o / _p T _y. No. No. 1 specimen or No. 1 The envelope of the two specimens is also indicated by a dotted line.
No. One specimen has a θ of 2.0 × 10 ⁻³ rad. At that time, the m was 5.5%, and even at the final deformation, the m was 15%. Compared to 2, it is extremely small.

In contrast, no. 2 specimens have a θ of about 13 × 10 ⁻³ rad. At that time, the bulge due to the compression yielding of the beam wood was confirmed in the bending compression zone of the left and right beam ends. In particular, as shown in FIG. 24, the bending compression range when the left beam was positively applied was remarkable. This part was completely compressed and yielded, and it could be judged that the compressive strength had decreased at the time of large deformation. In addition, when the negative force was applied, lateral buckling of the beam as shown in FIG. For this reason, at the time of the negative force of the left beam in FIG. 13 (b), the deformation opens between the loops of each cycle after the cycle immediately before reaching the proof stress.

No. 2 The bending strength was reached with the help of the left beam of the specimen, and θ was 8.9 × 10 ⁻³ rad. After that, the yield strength is reduced and the increase in the rotation angle is also reduced. This is because the compression yielding in the bending compression zone of the left beam was remarkable as described above. It is considered that the decrease in yield strength is due to the deterioration of the bending compression characteristics and the decrease in the bending compression resultant force and the bending stress center distance j. As shown in Figure 13 reduces the rotational angle increments of left beams (b) is 15 and 25, deformed to have L ₂ section outer L ₃ compressive yield spreads up interval measurements during the force This is because the bending deformation in the vicinity of the beam end surface corresponding to the deformation of the beam tip being controlled is dispersed in L ₂ and L ₃ . In FIG. The m-R relationship of 2 test bodies is shown. In the figure, R is the member angle of the beam. The left and right beams have the same deformation angle.

In FIG. 2 The bending strength was reached even on the positive force side of the specimen, and θ was 13.9 × 10 ⁻³ rad. Since then, the proof stress has been reduced, but not as much as when the left beam was positively applied. FIG. 26 shows the bending compression regions of the left and right beams after the experiment is completed. As shown in Fig. 3 (a), the compression force _w C at the lower end of the left beam balances with the tensile force 2 · _p T of the upper and lower PC bars, so if _w C during bending strength decreases, the bending of the right beam The tensile force _pT also decreases. However, in the right beam, the bending compression region hardly deteriorates, so the distance j does not decrease, and the decrease in bending strength is considered to be moderate.

In this joining method, since the PC bar is not fixed in the joint, the bending compression force needs to withstand twice the yield strength of the PC bar in a cross-shaped frame in which beams are attached to both sides of the joint. It should be noted that when the resultant compressive force is reduced, it affects the bending strength of the left and right beams. However, as can be seen in FIGS. 13 (b) and 14, the bending strength of the left and right beams hardly decreases to the final deformation angle when the load is applied. This is from the resultant force _w C _y of the compression zone of the bending yield compression idea to design smaller a force 2 · _p T _y yield strength of the upper and lower PC steel bars, a stable strength to a large deformation zone It means that it can be demonstrated. Naturally, in a lower frame with a beam attached to only one side, bending compression yielding hardly occurs, and a decrease in yield strength hardly occurs.

Method for Evaluating Moment-Rotation Angle of Beam End Face of Joint Part First, the conditions for deformation will be described.
FIG. 16 shows an assumed condition for adaptation and resistance elements. Here, assuming a two-dimensional stress state in which the linearity of the column axis in the joint is maintained, the axis can be regarded as a neutral plane continuous in the column width direction. In that plane, plane maintenance is assumed. The surface is defined as a column axis surface I. On the other hand, the prestress is introduced by tightening the left and right nuts 8 of the PC bar 7. Considering the conforming condition of the deformation of the tension spring representing the PC steel bar 7, the section located on the outer surface of the bottom of the U-shaped metal part is defined as the section II, and the flatness thereof is also maintained.

Regarding the mechanical spring model, FIG. 17 shows the spring model. The resistance mechanism in the section of the left and right section II is modeled. Compression springs are provided on the left and right sides of the column axis surface I in the joint. As shown on the right side of FIG. 16, two types of compression springs are provided in the height direction, divided into a section “a” of the height W of the upper and lower square washers and a section “b” inside thereof. In the joint, a compression spring k _c1 representing indentation reinforcement is provided in section a, and section b is provided with a bending section spring having a section (D _B × B) having a Young's modulus E _w1 of the wood part in a direction perpendicular to the fiber. Similarly, the beam is provided with a compression spring k _c2 representing a wood portion in the fiber direction in the section a, and the section b is provided with a bending section spring having a section (D _B × B) having a Young's modulus E _{w2 in} the fiber direction. These compression springs shall not resist if they turn to tensile resistance. On the other hand, the tension-resisting spring is provided with a tension spring k _pc of PC bar connecting the left and right sections II. The names k _c1 , k _c2 , and k _pc represent the axial stiffness of the spring.

In connection with the pre-stress effect enabled when the flexural stiffness _m K _o, showing a deformation state when prestress introduced in FIG. 18 (a). Section II of the left and right stop by just delta _o the cylindrical axis plane I. When the moment M acts on the beam as shown in FIG. 18B, the compression spring K _c (the one in which k _c1 and k _c2 are connected in series) decreases from the initial compression deformation Δ _o . In a variant delta _t of the return is delta _o lesser extent, stiffness according to the stiffness K _c of the compression spring.

On the other hand, if the left and right moments of the tension spring k _pc of the PC steel bar are the same, the deformation of the left and right cross-sections II is inversely symmetric with respect to the column axis surface I, so that no deformation occurs. Although it is not necessarily antisymmetric, it is approximated in that state here. Only the compression spring K _c affects the moment M in this state and the bending stiffness _m K _o of the rotation angle θ. _m K _o is expressed by the axial rigidity K _c of the section a and the bending section performance of the section b. This is expressed by the formulas (2) and (3).

M = _m K _o · θ (2)
= K _c · j _r / 2 · θ · j _r + E _wb · I _b · θ / L
_{m K o = K c · j} r 2/2 + E wb · I b / L (3)

Where K _c = 1 / (1 / k _c1 + 1 / k _c2 ), k _c1 = E _ws · A _ws / L ₁ ,
k _c2 = E _w2 · A _w2 / L ₂ , E _wb = E _w2 / (n · L ₁ / L + L ₂ / L),
_{n = E w2 / E w1,} L = L 1 + L 2, I b = B · D B 3/12
K _c : Shaft rigidity k _c1 and k _c2 connected in series j _r : Distance between the centers of gravity of the upper and lower indented reinforcing bars k _c1 : Axial rigidity E of the _indented reinforcing bar in section a _ws : Young's modulus A _{ws of the} indented reinforcing _bar : Total area L _{1 of the} reinforcement reinforcement in the section a L: _{1/2 of the} column, L ₂ : see FIG. 14 k _c2 : axial rigidity E _w2 of the wood part of the section a: Young's modulus in the fiber direction of wood, A _w2 : section a cross section 蹟 E _{wb of the xy part of a} : apparent tangent coefficient I _b when the range of the _{xy part of the} section b is connected in series from the column axis plane I to the cross section II: the cross section of the cross section (B × D _B ) next moment, D _B: due to the interval b E _w1: Young's modulus of the wood in the direction perpendicular to the fibers of the wood

Next, the moment _Mo when the prestress effect disappears will be described.
The prestress effect here is that the compression springs are all compressed and the bending rigidity of the beam end faces increases depending on the axial rigidity of the reinforcing bars.
When the prestressing effect disappears, returning to the previous initial shape spring K _c is prestressed, it is time to turn in tension. This is the time when the axial compression deformation Δ _o of the compression spring K _c when prestress is introduced is canceled by the tensile deformation Δ _t caused by the moment M. The original tension T _o per PC bar due to pre-stress is expressed by the product of Δ _o and the axial stiffness of the compression spring that is half of the beam, as shown in equation (4). _Δt is expressed by the product of the distance j _r / 2 from the cross-sectional centroid of the beam to the compression spring K _c at the rotation angle θ as in equation (5). The delta _o and delta _t and absolute amount, than delta _o and delta _t equally be to moment M _o, rotational stiffness of large the moment it acts beam end face is reduced.

T _o = (K _c + E _wb · (B · D _B / 2) / L) · Δ _o (4)
Δ _t = θ · j _r / 2 (5)
If Δ _o and Δ _t in the above equation are set equal, θ by Equation (2) and _m K _o in Equation (3) are substituted and arranged for _Mo , the moment _Mo when the prestress effect disappears is (6 ) And (7).

M _o = T _o · j _r · α (6)
α = 2 · (K _c · L · j _r ² + 2 · E _wb · I _b )
/ ((2 · K _c · L + E _wb · B · D _B ) · j _r ² ) (7)
Here, K _c is the same as described above.

Next, a description will be given tangent flexural stiffness _m K ₁ after M _o.
When the moment is greater than the previous section M _o, flexural tensile side of the stiffness of Migihari as in FIG. 18 (c) depends on the axial stiffness K _c of the shaft stiffness k _pc and left compression spring PC steel bar. The compression spring on the lower right side no longer resists and can be ignored. The same applies to the left beam. Here, since the bending compression region becomes small, the resistance in the section b is also ignored. Only bending compression spring K _c which remains in compression side to resist.

The increment of the moment increases from M _o and .DELTA.M, thereby an increment of bending tensile strength of the beam [Delta] T, the bending ΔC increments of compression force, and increments the Δθ of the rotation angle of the cross section II to increase. The relationship between ΔM and ΔT is expressed by equation (8) from the balance of moments around the compression spring position. Since ΔC balances with the increase ΔT in the tensile force of the upper and lower PC steel bars generated in the section II in the horizontal direction, it is expressed by equation (9). Horizontal deformations Δ _c and Δ _t at the upper and lower PC bar positions in the section II with respect to the column axis surface I are:
It is represented by the formulas (10) and (11).

ΔM = ΔT · j (8)
ΔC = 2 · ΔT (9)
Δ _c = ΔC / K _c (10)
Δ _t = ΔC / K _c + ΔT / k _pc (11)

The increment Δθ of the rotation angle is expressed by equation (12). Substituting to organize it to (8) from equation (11), M _o subsequent incremental moment - rotation angle relation is expressed by equation (13) and (14).

Δθ = (Δ _c + Δ _t ) / j (12)
ΔM = _m K ₁ · Δθ (13)
_m K ₁ = j ² / (4 / K _c + 1 / k _pc ) (14)
Where k _pc = E _pc · A _pc / L _pc
K _c : Same as in Section 5.3, k _pc : axial rigidity of PC steel bar, E _pc : Young's modulus of PC steel bar, A _pc : sectional area of PC steel, L _pc : inner length between left and right nuts , J: Stress center distance from the center of gravity of indentation reinforcement to PC bar

Next, the final moment _Mu will be described.
In this bonding method, the bonding area of the legs of the U-shaped fittings as described above ensures that because W and the bending tensile force _w T _By the cross-sectional area of Ryoboku portion consisting Ryohaba B As can be transmitted . _w T _by can be evaluated by multiplying the bending reference strength F _b by the cross-sectional area (W × B). In this bonding method is made smaller than that _w T _By the yield strength _p T _y of PC steel bars are designed to bend tensile yield the PC steel bars is preceded. In the test of the present embodiment is set to 78% of _p T _y / _w T _by. On the other hand, the bending compression side is bent and compression yielded on the beam side because the reinforcing part is sufficiently reinforced with reinforcement in the joint.

When the upper and lower PC steel bars is tensile yield, compression force _w C of Ryoboku portion than the balance of horizontal forces, as shown in FIG. 18 (d), it is twice the yield strength _p T _y. When the fiber direction of the xylem is compression yielding, it is ductile, and the yield stress level can be maintained up to a certain strain. For simplicity, it is assumed that the yield stress degree is F _b and the bending compressive stress distribution is a rectangular distribution of X. Based on the design policy of the PC steel bar described above, X is less than twice W. In the case of this test body, it is twice 77% of W, that is, 1.54W. In this joining method, since W is 20% of the beam D, X is about 30% of D.

No. If the status of the experiment 2 Specimen shape ratio PC steel bar and the U-shaped fittings are assumed in this bonding method, after the PC steel bar has tensile yield, the ultimate moment M _u Ryoboku unit compresses yield It is considered to reach. M _u is expressed by equation (15) from the balance of moments around the center of gravity of the bending compression force. _w C is expressed by equation (16), the relationship between the _p T _y is represented by the balance, mosquito (17). From both equations, X is expressed by equation (18). By substituting this into the equation (15) and arranging it, _Mu is expressed by the equation (19).

M _u = _p T _y · (d−X / 2) (15)
_w C = F _b · X · B (16)
_w C = 2 · _p T _y (17)
X = 2 · _p T _y / (F _b · B) (18)
M _u = _p T _y · d · (1− _pt · σ _y / F _b ) (19)
_{Here, p t = a t / (} B · d)
_p T _y: the yield strength of the PC steel bar, d: due to the PC steel bars of the tensile edge from compression edge, B: the beam width,
p _t: tensile reinforcement ratio of PC steel, a _t: single cross-sectional area of the PC steel bars, sigma _y: yield stress of the PC steel bars, F _b: xylem flexural reference intensity

Next, a model of the moment-rotation angle relationship of the beam end face will be described.
FIG. 19A shows a history model of the moment-rotation angle relationship when the beam receives repeated moments. If the loading until M _o moments (6) according to the relationship of the expression (2), in accordance with the relationship becomes greater than M _o (13) where the moment (19) reaches the formula M _u, PC It is assumed that plastic deformation occurs in the steel bar, the moment is constant, and the rotation angle increases. At this time, there is almost no indentation deformation in the joint on the bending compression side of the beam end face, but the bending compression area of the beam compressively yields and plastic deformation increases. As the rotation angle increases, the compression characteristics decrease and the moment begins to decrease. The moment is defined as the limit rotation angle rotation angle when lowered to a certain ratio of M _u. The rotational performance is governed by the cross-sectional performance of the beam regardless of the joint.

On the other hand, when unloading, the Level1,2 moment acts is small as is seen in FIG. 12, after receiving the M _o greater moment, be unloaded back nearly path during loading. However, when unloading is performed at Level 3 where the acting moment is large, a plastic rotation angle component is generated and the route does not return to the route at the time of loading. Based on this, modeling is performed as shown in FIG. When a plastic rotation angle is generated after bending yielding and the load is changed to unloading, it returns with the rigidity of _m K _{1 in} the equation (14).

If the sum of the plastic deformation Δ _p (FIG. 18 (d)) of the PC bar tension spring k _pc and the compression spring K _c at the peak of each cycle is smaller than the deformation Δ _o generated when pre-stress is introduced, the pre-stress effect remains. , path back of a rigid _m K ₁ merges the initial M _o following M-theta relationship as shown in FIG. 19 (b). Let the junction point be P _c . However large rotation angle at peak, the delta _p is greater than delta _o cycle confluence P _c does not appear. In this case, when the moment at the time of unloading approaches zero, as shown in FIG. 19B, there appears a point where the deformation suddenly changes to the rigidity to return to the initial state. This point is defined as a _Pr point. This _Pr point is No. It occurs even in one specimen. This is considered to be the effect of prestress. Here, the moment at the _Pr point is set to 10% of the standard bending strength of the beam section based on the experimental results. Unloading stiffness after P _r point shall be directed to the origin.

Evaluation No. by moment-rotation angle evaluation method The moment-rotation angle relationship between the beam ends of the two specimens and the layer shear force-interlayer deformation angle relationship were evaluated.
First, the moment-rotation angle relationship of the beam end face will be described.
(A) Initial rigidity and moment when prestress effect disappears The calculated relationship is shown by a broken line in the above-described M-θ relationship of FIG. Rigidity of up to M _o is a well with the experimental results. The moment M _o (the horizontal one-dot chain line toment) at which the pre-stress effect disappears and the rigidity decreases is in good agreement with the experimental value (at the time indicated by ◯ in the figure) with the positive forces of Level 1, Level 2, and Level 3. The experimental value is somewhat smaller with the negative force of Level3. In this cycle, there is some area in the loop, which is considered to be caused by plasticizing the material with a positive force. M _o larger range tangent _m K ₁ also has a well with the experimental results.

(B) Relationship between moment and rotation angle of beam end face FIG. 20 shows a comparison between the calculation results and the experimental results. Experiments in which was 0.94 T _o / _p T _y described above, and has the same value in the calculation. The maximum rotation angle for each cycle of calculation is adjusted to the experiment. The calculated final moment was estimated to be 9% smaller than the experimental value. This is thought to be due to the variation in yield strength due to the yield of the threaded portion of the PC steel bar (Fig. 28), the fact that the cross-sectional position of the beam is at the end of the beam, and the yield strength of the bending compression of the beam as the reference value. It is done.

± up to three cycles, there may unloading time and re-loading of the rigid, P _c that it revived prestressing effect during unloading, calculation results, such as the moment M _o prestressing effect disappears during re-loading the experimental results ing. At the time of unloading of ± 4 cycles, the moment at the calculated P _c point is almost zero, which is slightly smaller than the experimental value, and there is a slight difference in the stiffness immediately before the P _c point. However, _Pc point does not occur at the time of unloading after ± 5 cycles. This is because the plastic deformation delta _p of elongation of PC steel bar as described above is larger than the axial deformation delta _o when prestress introduced.

At the time of ± 5 cycles after unloading, P _r point which changes abruptly rigid directed origin occurs. On the other hand, the calculated value of the unloading stiffness immediately before that needs to be slightly smaller than _m K ₁ due to a difference from the experimental value. Plastic deformation delta _p of elongation of the PC steel bars is greater than the delta _o, the rigidity of the subsequent P _r point has occurred is required due to repeated bending analysis.

Next, the relationship between the layer shear force and the interlayer deformation angle will be described.
FIG. 22 shows a comparison between the calculation results and the experimental results. FIG. 21 shows the model used for this calculation. For the deformation of the joint and the beam end face, the elastic bending deformation was calculated from the section II to the applied tip of the beam using the M-θ relationship of FIG. As for the column, the elastic bending deformation was calculated by providing a rigid region at the joint portion in the same manner as in the above calculation III.

In one cycle, the rigidity up to about 70% of the calculated maximum load value _c P _max is in good agreement with the experimental value. The deformation angle of the experiment is larger than the calculated value after -5 cycles of negative force. This is because, as shown in FIG. 29, in the same cycle, the bending cracks near the bending risk section of the lower column expanded and progressed, and the column deformation increased. If this is excluded, it can be judged that the calculation result of FIG. 22 estimates the experimental result well macroscopically.

  In the figure, the deformation angle limited in the design is indicated by a two-dot chain line. The interlayer deformation angle (1/120 rad.) Exhibits only about 65% of the maximum load. The yielding deformation angle is 1/80 rad. The yield energy of PC bar cannot be used unless it is in a large deformation range. However, from the viewpoint of suppressing residual deformation without collapsing the building in the event of a large earthquake, this joining method is effective because it has a high yield strength and energy absorption.

Next, energy absorption and equivalent viscosity damping constant will be described.
In this joining method, the PC steel bar is tensile yielded, so a clear energy absorption amount can be secured. The loop area of each cycle in FIG. 22 means the amount of energy absorption. Since it is larger than one specimen, the amount of absorption is large. FIG. 23 on the previous page shows the change of the equivalent viscous damping constant obtained from the M-θ relationship in the calculation of FIG. 20 in comparison with the experimental value. The horizontal axis is the rotation angle θ of the beam end face. In the figure, no. Experimental values for one specimen are also shown.

The calculated value is No. It is slightly larger than the experimental value of 2 specimens. This is because the moment at the _Pr point at the time of unloading in FIG. 19 is set small. However, this is macroscopic, and the equivalent viscous damping constant can be set by calculation in this joining method. However, this joining method is not affected by the deformation history because it does not cause repeated compression and tension in the PC bar. It is necessary to study by dynamic analysis of various seismic waves. In addition, if the design is made to positively use the yield energy of the PC bar, a method in which the PC bar repeats tensile yielding and compression yielding is also effective.

  As described above, a joint method that can introduce a large prestress force with the intention of rigid joints of wooden ramen was explained, and the possibility was verified by a force test of a cruciform frame. And the evaluation method of the rotational performance of a junction part was demonstrated. In addition, this joining method is a method of assembling a pillar. Hereinafter, main effects and the like in the present embodiment will be described.

(1) With this joining method, it was possible to calculate the stress and deformation of the ramen as rigid joints up to 70% of the horizontal strength of the frame layer. The interlayer deformation angle of the frame at that time is about 1/120 rad. Thus, it can be calculated as a rigid joint within the range of deformation restrictions of the design. The degree of rigid joint at the joint was improved to the same level as the RC frame.

(2) By introducing prestress, the rotational rigidity of the joint increases, and the range in which the effect is effective varies depending on the magnitude of the prestress. No. of this embodiment. In the two specimens, the effect was confirmed up to a moment of about 60% of the base bending strength of the base material of the beam.

(3) The bending strength of the beam was 70% of the base bending strength of the base metal due to the tensile yielding of the PC bar. This bending strength is 45 × 10 ⁻³ rad. I was able to hold. However, because the PC bar is not fixed in the joint, the bending compressive force of the beam is twice that of the PC bar, the beam is bent and compressive yielded, and its compressive characteristics deteriorated in the large deformation region, resulting in a decrease in bending strength. did. In order to prevent this, it is necessary to suppress the yield strength of the PC bar or to fix it in the joint of the PC bar.

(4) The deformation of the PC steel bar to yield strength is 24 × 10 ⁻³ rad. And the interlaminar deformation angle of the frame is 1/80 rad. The yield energy of PC bar cannot be used unless it is in a large deformation range. However, this joining method ensures large yield strength and energy absorption, so it is effective from the viewpoint of preventing collapse of buildings or suppressing residual deformation in the event of a large earthquake.

(5) With the evaluation method of the present embodiment, the moment-rotation angle relationship of the beam end face at the boundary between the joint and the beam and the equivalent viscosity coefficient after yielding were almost estimated. The experimental results were also well estimated for the relationship between the layer shear force of the frame and the interlaminar deformation angle calculated using this.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. 30 and 31 show a second embodiment. In this example, the steel pipe 20 is fixed to the pillar 1 by an adhesive 22. A PC bar bolt 21 or a general bolt is passed through the inside of the steel pipe 20. As shown in FIG. 32A, the shape of the steel pipe 20 is provided with protrusions such as thread grooves on the outer surface of the steel pipe 20 in order to increase the adhesive force.

  In 2nd Embodiment, the structure is simplified by making the steel pipe 20 and the PC bar bolt 21 into a concentric double structure. By using both the through hole of the column 1 for a plurality of deformed steel bars to be fixed and the through hole of the column through which the PC steel bar 7 or general bolts are passed, the number of through holes in the column 1 is reduced and labor saving is achieved. At the same time, it is possible to reduce the loss of the column 1 and reduce the decrease in the rigidity and strength of the column.

(Third embodiment)
Next, a third embodiment of the present invention will be described. 33 and 34 show a third embodiment. In this example, female screws 30a are cut at both ends of the steel pipe 30 fixed to the pillar 1 as shown in FIG. 32 (b) or (c), and PC bar bolts 31 or general bolts having screw portions 31a at both ends are screwed. In these bolts 31, two nuts 32 and 33 are installed at the opposite end to the screwed end. The nut 32 is fastened to the PC bar bolt 31 for introducing a prestressing force of bolt tension. After this tightening, the nut 33 is turned and installed on the PC bar bolt 31, and the inserted steel material 35 is inserted between the hardware receiving portions 34. The nut 33 is rotated backward and brought into contact with the inserted steel plate 35. Thereby, a compressive force is transmitted between the PC bar bolt 31 and the metal receiving part 34. The receiving portion 34 is fixed to the U-shaped hardware 5 by welding 36.

In the above case, the type of the steel pipe 30 is the one shown in FIG. 32 (b) or (c). The type shown in FIG. 32 (b) is provided with a female thread inside the steel pipe, and the type shown in FIG. 32 (c) is provided with a female thread at both ends of a large-diameter deformed reinforcing bar or a large-diameter bolt.
Furthermore, the diameter of the central section in the bolt length direction of the PC steel bar bolt 31 is made smaller than that of the other sections, and the thread portions at both ends are yielded so as to yield clearly in that section. To prevent.

  In the third embodiment, the tensile yield and the compressive yield are repeatedly generated in the PC bar bolt 31 or the general bolt at the time of a large earthquake. As a result, the plastic energy of the PC steel bar is increased, and the vibration energy of the structure can be absorbed to reduce the vibration during a large earthquake.

(Fourth embodiment)
Furthermore, in the fourth embodiment of the present invention, as shown in FIG. 35, when the width of the column 1 and the beam 2 is increased, the steel pipe 40 and the PC bar bolt 41 are arranged in a plurality of rows in the column width direction and the beam width direction. Placed parallel to

  According to the fourth embodiment of the present invention, performance close to the base material can be exhibited when the column width or the beam width is increased.

(Fifth embodiment)
Furthermore, in the fifth embodiment of the present invention, a female screw having a predetermined length is provided at a substantially central portion in the longitudinal direction of the steel pipe 30 (see FIG. 32) (note that illustration is omitted). A PC bar bolt 31 or a general bolt (see FIG. 34 (a)) having screw portions 31a at both ends is screwed into the female screw from both sides in the longitudinal direction. Other basic configurations are substantially the same as those in the third embodiment.

  According to the fifth embodiment of the present invention, in addition to the effects of the third embodiment described above, the effect of the prestressing force can be obtained by extending the PC bar bolts 31 and the like to the inside of the steel pipe 30. The rigidity of the beam-column joint can be effectively enhanced by increasing it.

As mentioned above, although this invention was demonstrated with embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
For example, the quantity, size, etc. of PC bars and reinforcing bars can be increased or decreased as necessary. In addition, the material of these members can be appropriately used as long as it is equal to or higher than that in the above embodiment.
Further, instead of the U-shaped hardware, it is also possible to use a hardware in which steel materials having different thicknesses are combined in a U-shape and joined by welding. In this case, the thickness of each part of the hardware can be adjusted, and the optimum thickness of the steel material can be selected for each part against the stress generated in the hardware. As a result, the amount of steel used can be reduced, and there is an advantage that it is not necessary to bend a thick steel.

It is a figure which shows the principal part structure of the junction structure of this invention. It is a figure which shows the junction structure as a comparative example of this invention. It is a figure which shows the principle of transmission of the internal force in embodiment of this invention. It is a figure which shows the example of whole structure of the wooden structure member in embodiment of this invention. It is a figure which shows the structural example of the joint surface of the pillar and beam in embodiment of this invention. It is a figure which shows the structural example of the measuring apparatus which concerns on embodiment of this invention. It is a figure which shows the structural example of the measuring apparatus which concerns on embodiment of this invention. It is a figure which shows the relationship between the layer shear force and interlayer deformation angle in embodiment of this invention. It is a figure which shows each deformation | transformation component in the layer shear force and interlayer deformation in embodiment of this invention. It is a figure which shows the evaluation model of the rigidity of the rigid joint in embodiment of this invention. It is a figure which shows the comparative example of the experimental value and calculated value of initial stage rigidity in embodiment of this invention. It is a figure which shows the m-theta relationship of the applied cycle in embodiment of this invention. No. in the embodiment of the present invention. It is a figure which shows the m-theta relationship of 2 test bodies. No. in the embodiment of the present invention. It is a figure which shows the mR relationship of 2 test bodies. It is a figure which shows the example of a measurement area of the displacement meter A in embodiment of this invention. It is a figure which shows the deformation | transformation adaptation conditions and resistance element in embodiment of this invention. It is a figure which shows the example of a dynamic spring model in embodiment of this invention. It is a figure which shows the deformation | transformation state and stress state of each time in embodiment of this invention. It is a diagram showing a history model M _B - [theta] relationship in the embodiment of the present invention. It is a graph showing by comparison the calculated results and experimental results of the M _B - [theta] relationship in the embodiment of the present invention. It is a figure which shows the example of a model of QR relationship in embodiment of this invention. It is a figure which compares and shows the calculation result and experiment result of QR relationship in embodiment of this invention. It is a figure which shows the change of the equivalent viscous damping constant in embodiment of this invention. It is a photograph which shows the bending compression area under the left beam in embodiment of this invention. It is a photograph which shows the left beam under deformation measurement area in embodiment of this invention. It is a photograph which shows the condition of the bending compression zone of the beam after completion | finish of experiment in embodiment of this invention. It is a photograph which shows the condition of the lateral buckling of the left beam in embodiment of this invention. It is a photograph which shows the yield condition of the thread part of PC bar steel in the embodiment of the present invention. It is a photograph which shows the bending crack condition of the pillar in embodiment of this invention. It is a figure which shows the principal part structure of the junction structure which concerns on the 2nd Embodiment of this invention. It is a figure which shows the principal part structure of the junction structure which concerns on the 2nd Embodiment of this invention. It is a figure which shows the example of the steel pipe which concerns on the 2nd Embodiment of this invention. It is a figure which shows the principal part structure of the junction structure which concerns on the 3rd Embodiment of this invention. It is a figure which shows the principal part structure of the junction structure which concerns on the 3rd Embodiment of this invention. It is a figure which shows the principal part structure of the junction structure which concerns on the 4th Embodiment of this invention.

Explanation of symbols

1 Column 2 Beam 3 Square Hole 4 Long Groove 5 U-Shaped Metal 6 Adhesive 7 PC Bar 8 Nut 9 Square Washer 10 Square Washer 11 Reinforcement 12 Through Hole 13 Through Hole 14 Mortise 15 Mortise 20, 30, 40 Steel Pipe 21 PC Bar Bolt 32, 33 Nut 34 Receiving part 35 Insert steel

Claims (6)

It is a joining member of a wooden column beam member that joins both members to each other in a joint portion including a column and a beam constituting a wooden structure,
A pressure-receiving member fixed in the column along the beam direction, and a fastening member extending through the column and extending into the beam along the beam direction,
A joining member for a wooden column beam member, wherein prestress is introduced into the pressure receiving member by tightening the fastening member.   2. The wooden column beam member according to claim 1, wherein the pressure receiving member is made of a reinforcing bar or a steel pipe material, the fastening member is made of a steel bar material, and a compressive load is applied to the pressure receiving member as a prestress. Joint fittings.   3. The joint member for a wooden column beam member according to claim 1, further comprising a washer that abuts and supports the pressure receiving member on an end surface of the beam in the joint portion.   The tenon hole which fits with the tenon is formed in the both sides | surfaces of the said pillar while providing one or several tenon in the end surface of the said beam, The any one of Claims 1-3 characterized by the above-mentioned. Joints for wooden column beams.   The said pressure receiving member and the said fastening member are comprised by the concentric double structure, The joining bracket of the wooden pillar beam member of any one of Claims 1-4 characterized by the above-mentioned. A method for joining wooden column beam members, in which both members are joined to each other in a joint including columns and beams constituting a wooden structure,
A wooden structure characterized in that a prestress is introduced into the pressure receiving member by fixing a pressure receiving member inside the joint portion of the column and tightening a fastening member penetrating the column along the beam direction. Method for joining column beam members.