Technical field
[0001]
　The present invention relates to a joint structure of the beams and columns, and in particular Precast concrete (half PCa) structure of the joint portion of the beams and columns.
Priority is claimed based on Japanese Patent Application No. 2015-198053 filed in Japanese on October 5, 2015, which is incorporated herein by reference.
Background technique
[0002]
　Conventional, improvement of the construction period of the reduction and safety, improvement of quality, because it has many advantages, such as in turn reduce costs, and PCa elephant was produced in advance factory, such as the beams and columns of concrete-based buildings, these on-site it has been made that in assembled to construct the building.
[0003]
Also, as a joining method for PCa Concrete beams and columns, for example, a reinforcing bar for joining the side end face of the beam to be joined to the side surface of the pillar side and the pillar is provided, the side end face of the beam that joining reinforcing bars are arranged and Da設 the poured concrete between the side posts, a method of integrating joining beams and columns via these joining reinforcing bars and poured concrete is used.
[0004]
Further, the lower projecting the lower side of the shear reinforcement and the lower main reinforcement is formed as a half PCa beam and embedded in concrete, the lower reinforcing bar for junction protruding from pillars (site Haisuji main reinforcement) from joining end face of the half PCa beam main reinforcement superposed, and the bonding upper reinforcing bars protruding from the pillar with connecting to shear reinforcement exposed from the upper surface upwardly disposing the upper main reinforcement (site Haisuji main reinforcement) superimposed on the upper main reinforcement, projecting from the column and joining rebar, connected by joints overlapping main reinforcement of the beam, the PCa concrete beams and pillars to cast-in-place concrete at the junction of the half PCa beams on and columns are also practical construction method of joining together there.
[0005]
Also, as disclosed in Patent Document 1, there are a joining reinforcing bars protruding from the pillar, also construction method to connect with perforated lap joint superposing at intervals and main reinforcement of the half PCa beam.
CITATION
Patent Document
[0006]
Patent Document 1: Japanese Laid-Open Patent Publication No. 11-81452
Summary of the Invention
Problems that the Invention is to Solve
[0007]
On the other hand, construction method to connect fitting superimposed main reinforcement of the bonding reinforcing bar and half PCa beam pillars its design technique has been established, Aki to the main reinforcement of the bonding reinforcing bar and half PCa Beams pillars overlaid with an interval design of construction method to connect a lap joint is not well established.
[0008]
In view of the above circumstances, it makes it possible to suitably bond the beams and columns with perforated lap joint to the main reinforcement of the bonding reinforcing bar and half PCa Beams pillars superimposed spaced beams and columns of and to provide a joint structure.
Means for Solving the Problems
[0009]
　The present invention, in order to solve the above problems, employs the following aspects.
[0010]
(1) junction structure of beams and columns according to one embodiment of the present invention, the beams are connected by perforated lap joint overlap the main reinforcement of the joining reinforcing bars and beams protruding from the pillar laterally at predetermined intervals and a structure for joining the pillars, lap joint length L of the said joining rebar main reinforcement is required fitting length L of the perforated lap joint calculated by the following equation (1) d is set to be equal to or greater than and wherein the are.
[0011]
[Number 1]

[0012]
Here, L p is a joint invalid length (mm). f y is the yield strength of the reinforcing bars (N / mm 2 are), the standard point strength. a s the cross-sectional area per one beam main reinforcement (mm 2 ), phi is the circumferential length per one beam main reinforcement (mm), tau bmax the adhesion strength of the beam main reinforcement (N / mm 2 is).
[0013]
The joint invalid length L p is, 1 ≦ R b / R e ≦ 2.5 × below when gamma + 1 Equation (2), 2.5 × gamma + 1 1.5D L the p- a = 1.5d.
[0014]
[Number 2]

[0015]
[Number 3]

[0016]
a clear span of the beam length (mm), D is the total blame beams (mm), R d is the design target member angle (rad). R E is the ACI (American Concrete Institute) surrender deformation angle defined the criteria (rad). d is the blame effectiveness of the beam when the beam pull the lower end (mm). The γ and β are affected factors by Shiasupan ratio (a / D), the following equation (4), determined by equation (5).
[0017]
[Formula 4]

[0018]
[Formula 5]

Effect of the invention
[0019]
According to the joint structure of the beams and columns according to the embodiment of the present invention, conventionally, it is possible to realize a joint structure of high reliability beams and columns with perforated lap joints whose design method has not been established possible to become.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020]
FIG. 1 is a sectional view showing the joint structure of the beams and columns according to an embodiment of the present invention.
It is a [FIG 2] X1-X1 sectional view taken along the line diagram of Fig.
3 is a diagram illustrating a reinforcing bar stress distribution of the joint portion of the joint structure of the beams and columns according to an embodiment of the present invention.
4 is a conceptual diagram showing a joint slippage strength of the joint structure of the beams and columns according to an embodiment of the present invention.
[Figure 5] is a X1-X1 sectional view taken along the line of FIG. 4 is a conceptual diagram showing a joint sliding surface of the joint structure of the beams and columns according to an embodiment of the present invention.
6 is a diagram showing a stress block method in ACI318.
[7] The ratio because the effective beam joint invalid length (L p is a graph showing the relationship / d).
8 is a sectional view showing a test specimen was used to verify the validity of the design method of the joint structure of the beams and columns according to an embodiment of the present invention.
9 is a X1-X1 sectional view taken along the line diagram of FIG.
Is a X2-X2 view taken along line diagram of FIG. 10 FIG.
11 is a X3-X3 sectional view taken along line diagram of FIG.
DESCRIPTION OF THE INVENTION
[0021]
　Hereinafter, with reference to FIGS. 1 and 11, it will be described joint structure of the beams and columns according to an embodiment of the present invention. Here, the present embodiment is intended as reinforced concrete (RC) manufactured pillar relates to a structure for joining a precast concrete beam (PCa beam).
[0022]
　First, PCa beam 1 according to this embodiment, as shown in FIGS. 1 and 2, a U-shaped half PCa beam, the central portion in the width direction of the axis O1 direction end side (side edge closer) is, recessed from the upper end to the lower end to form a U-shaped cross-section provided between the concrete 設空 to pouring the cast-in-place concrete (poured concrete section) 2.
[0023]
　Further, the half PCa beam 1, concrete 設空 between 2 are formed recessed to below the center of the Sei Ryo from the upper end (the height direction center).
[0024]
　Thus, the lower main reinforcement 3 half PCa beam 1 are embedded in the concrete of the half PCa. Further, shear reinforcement 4 is embedded lower side the concrete, the upper end side from the axial line O1 direction central portion and the upper surface of the concrete 設空 between 2 half PCa beam 1 so as to protrude upward, half PCa beam 1 It is formed.
[0025]
　Incidentally, the head thickness of the upper and lower main reinforcement 3 half PCa beam 1 of concrete 設空 between 2 is set so as to ensure a predetermined distance between the perforated lap joint 5 which will be described later. The thickness of the half PCa of the U-shaped portion forming a concrete 設空 between 2 is about 80 mm.
[0026]
　On the other hand, posts 6 according to the present embodiment is a PCa Columns and RC columns, joining end face for bonding the half PCa beam 1 joining the lower reinforcing bar 10 (or bonding the upper reinforcing bar) while embedded in concrete together ( It is formed so as to protrude laterally from the pillar face portion) 6a.
[0027]
　Then, in the joint structure A of the beams and columns according to the present embodiment, the bonding upper reinforcement 7 projecting from the pillar 6 and the upper main reinforcement half PCa beam 1, projecting from the upper surface of the half PCa beam 1 upward shear to connect close to the upper end of the reinforcement 4. Also Haisuji cap muscle 8 so as to surround the upper main reinforcement 7 with shear reinforcement 4.
[0028]
　Further, bonding the lower reinforcing bar 10 projecting from the pillar 6, the half PCa disposed close to the upper surface of the concrete 設空 between second beam 1, a predetermined distance above the lower main reinforcement 3 half PCa beam 1 which is embedded in the concrete It is provided with a.
[0029]
　Then, on the concrete 設空 between 2 and half PCa, shear reinforcement 4 and the upper main reinforcement 7, by pouring concrete so as to bury the cap muscle 8, joining the half PCa Beams 1 and column 6.
[0030]
　The joint structure A of the beams and columns according to the present embodiment, the lower main reinforcement 3 of the lower reinforcing bar 10 for bonding protrudes from the pillar 6 and the half PCa beam 1 is predetermined in this way join the half PCa beam 1 and the bar 6 superimposed at a distance, the joint portion connecting the bonding lower reinforcing bar 10 and the lower main reinforcement 3 is configured as a joint 5 superimposed perforated.
[0031]
　Will now be described design method in the case of a joint 5 lap autumn the joint portion of the lower main reinforcement third lower for joint projecting from the pillar 6 rebar 10 and the half PCa beams 1 as described above.
[0032]
(Bending calculated for the moment)
　First, calculation for the bending moment of the joint structure of the beams and columns according to the present embodiment is performed based on 1-1), 1-2) below.
[0033]
　1-1) Architectural Institute of Japan ed., "Reinforced concrete structure calculation criteria, the same explanation - 2010 Edition" (hereinafter referred to as RC criterion), or on the basis of ACI318, to calculate the stress intensity in the cross section, the allowable bending moment, or ultimate flexural seek strength. It may be calculated based on group standards such as applied in the country or the region.
　1-2) Minimum main reinforcement of the beam is subject to the provisions of the design criteria to be applied.
[0034]
(Calculated for shear)
　Next, the calculation for the shearing of the joint structure of the beams and columns according to the present embodiment, 2-1 below), 2-2), and based on 2-3).
[0035]
　2-1) based on RC criterion or ACI318, determine the allowable shear force or ultimate shear strength. It is also based on criteria such as applied in the country or the region.
　2-2) Minimum shear reinforcement ratio, subject to the provisions of the design criteria to be applied.
　2-3) shear is calculated by U-shaped fore portion (concrete portion) and joint finishing portion.
[0036]
(Aki lap joint design)
　The perforated lap joint of the junction structure of the beams and columns according to the present embodiment is designed by the following procedure 3-1) to 3-5).
[0037]
　3-1) design target maximum deformation angle R d defining the.
　3-2) requires joint length L d is calculated.
　3-3) requires lateral reinforcement amount p of the joint portion wd is calculated.
　3-4) confirms conformance to ACI criteria lap joint length L.
　3-5) performing shearing design other than joint portion.
[0038]
　In this design method, the beam dangerous section is the pillar face portion, the stress distribution in the joint reinforcement assumes the shape as shown in FIG. 3. Further, to contribute to the joint sliding strength is dowel Shear Strength of Friction Properties and transverse reinforcement of the punching joint interface of the joint portion, with respect to setting of the joint sliding surface and as shown in FIGS.
[0039]
(Design target maximum deformation angle R d setting)
　the design target member angular Rd when providing the lap joint to yield a hinge portion of the beam end, wherein as shown in (6), limit deformation angle R based on the ACI criterion x less selected so as to be.
　Also, R x by equation (7), R e is determined respectively by Equation (8). Furthermore, the case of providing a lap joint in addition to the yield hinge R d = R e and.
[0040]
[Number 6]

[0041]
[Number 7]

[0042]
[Number 8]

[0043]
　Here, R x is a limit drift angle (rad). C d is a plastic magnification, according to Table 1 below.
[0044]
[Table 1]

[0045]
　Also, phi · M n is the design bending ultimate strength when pulling beam lower (N · mm), on the basis of the stress block method shown in FIG. 6, the following equation (9), determined by equation (10).
[0046]
　Furthermore, L b is the beam clear span length (mm). E c is the Young's modulus of the concrete (N / mm 2 are), according to equation (11). Also, I cr is reduced geometrical moment of inertia of the beam (mm 4 a), according to equation (12).
[0047]
Further, f c 'is design strength of poured concrete (N / mm 2 ), b is the beam width (mm). I g Liang second moment (mm 4 is).
[0048]
[Number 9]

[0049]
[Formula 10]

[0050]
[Number 11]

[0051]
[Number 12]

[0052]
(Required fitting length L of the perforated lap joint d calculation of)
　Next, requires joint length L of the perforated lap joint d describing calculation of.
　In this embodiment, necessary coupling length L of the perforated lap joint portion d was calculated by the equation (13), the lap joint length L L d so as to ensure more.
[0053]
　Here, L p is a joint invalid length (mm). f y is the yield strength of the reinforcing bars (N / mm 2 are), the standard point strength. a s the cross-sectional area per one beam main reinforcement (mm 2 ), phi is the circumferential length per one beam main reinforcement (mm), tau bmax the adhesion strength of the beam main reinforcement (N / mm 2 is).
[0054]
[Formula 13]

[0055]
　Joint invalid length L p is, 1 ≦ R b / R e formula (14) below when ≦ 2.5 × gamma + 1, 2.5 × gamma + 1 1.5D L the p- a = 1.5d.
[0056]
　Here, a is the beam of Shiasupan (mm), D is the total blame beams (mm), R d is the design goal member angle (rad). R e is a yield drift angle stipulated in ACI criterion (rad), obtained by the above equation (8). D is the blame effectiveness of the beam when the beam pull the lower end (mm). The γ and β are affected factors by Shiasupan ratio (a / D), the following equation (16), obtained by equation (17).

claims.
1.　A structure for joining the beams and columns and connects the main reinforcement of the transverse joining reinforcing bars and beams protruding from the pillar in perforated lap joint overlap at a predetermined distance,
　overlapping the said bonding reinforcing bar main reinforcement joint length L is required fitting length L of the perforated lap joint calculated by the following equation (1) d joint structure of beams and columns, characterized in that it is set to be higher.
[Equation 1]

　Here, L p is a joint invalid length (mm). f y is the yield strength of the reinforcing bars (N / mm2), and the standard point strength. a s the cross-sectional area per one beam main reinforcement (mm2), φ is the circumferential length per one beam main reinforcement (mm), tau bmax is the adhesion strength of the beam main reinforcement (N / mm2).
　The joint invalid length L p is, 1 ≦ R b / R e ≦ 2.5 × below when gamma + 1 Equation (2), 2.5 × gamma + 1 1.5D L the p- a = 1.5d.
[Number 2]

　a Liang clear span (mm), D is the total blame beams (mm), R d is the design goal member angle (rad). R e is yield drift angle stipulated in ACI criterion (rad). d is the blame effectiveness of the beam when the beam pull the lower end (mm). The γ and β are affected factors by Shiasupan ratio (a / D), the following equation (4), determined by equation (5).
[Number 4]