JPH0874319A - Joint building construction between precast concrete beam and column with circular section - Google Patents

Abstract

PURPOSE: To simplify the method for constructing a frame of a column and beams and enhance the working efficiency at a site by placing a tensile material passing through commonly sectional insides of joint ends of beams in a circular shape at a plane view, and straining it strongly to produce inward centripetal force. CONSTITUTION: Precast concrete beams 3... providing joint ends 2... having a shape dividing a circle large by thickness necessary for joint rather than the appearance of a column 1 to mounting positions of the beams of the column 1 with a circular cross-section are constructed by bringing their joint ends 2 into contact with the circumference of the column 1. After that, a space 4 between each of the joint ends 2 and column 1 is filled with filler. Then, a tensile material 5 commonly passing through sectional insides of the joint ends 2 of the beams 3 is placed in a circular shape at a plane view. After the filler in the space 4 is solidified, the tensile material 5 is strongly strained to produce inward centripetal force, and the beams 3 and column 1 are strongly bound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a column having a round cross section, such as a concrete-filled steel pipe column, a precast concrete column or a cast-in-place concrete column, and more particularly a steel frame column (hereinafter collectively referred to as a round section column). The method of constructing a column-beam frame by joining precast concrete beams with prestress.

[0002]

2. Description of the Related Art Heretofore, as a construction method (joint construction method) for assembling a column-beam frame structure using a precast concrete member, the following are known and practiced. A construction method in which a tension member such as a PC steel wire is arranged so as to penetrate the column from the end of the beam, and the tension member is subjected to a strong tensioning treatment and joined (JP-A-5-39645 and JP-A-5-280092). reference). Reinforcing bar (anchor rebar) protruding from the end of the beam
A joint construction method in which the so-called pillar panel zone is embedded and integrated in concrete. A steel frame is integrally embedded in the end portion of the beam, and the steel frame is joined to the column steel frame (Japanese Patent Laid-Open No. 53-1408).
17, JP-A-60-138139, JP-A-1-28
7338, JP-A-2-266034, JP-A5-1
(See inventions such as Japanese Patent No. 48898). A joining construction method in which the above and are combined to form a composite.

[0003]

[Problems to be Solved by the Invention]
All of the joining construction methods of the work to open a hole that penetrates the pillar,
It is necessary to embed a steel frame in the panel zone, or to assemble a complicated reinforcing bar in the panel zone, and at the work site or in a manufacturing factory, the column joint must be laborious. In addition, when constructing the pillars one by one, it is possible to provide a space for arranging the PC steel wire at the top end of the pillar, but since the pillars can only be built one by one, the work efficiency is poor. However, there was a drawback that the effect of shortening the construction period could not be expected.

Therefore, an object of the present invention is to construct a column beam structure by joining a precast concrete beam with prestress introduced to a concrete-filled steel tubular column or other round cross-section column to construct a PC steel wire and a reinforcing bar. The purpose of the present invention is to provide a joining construction method that simplifies the fitting around the crimping part to the pillar and improves the efficiency of field work and shortens the construction period.

[0005]

As a means for solving the above-mentioned problems, in the joining construction method of a precast concrete beam and a circular cross-section column according to the invention of claim 1, the cross section is formed into a round shape. A precast concrete beam 3 having a joint end portion 2 having a shape equal to that obtained by dividing a round shape, which is larger than the outer shape of the column by a thickness dimension required for joining, is formed at the beam mounting position of the pillar 1. 2 is attached to the outer peripheral surface of the column, and a filler is injected into the gap 4 between the joint end 2 and the column 1 so as to commonly penetrate the inside of the cross section of the joint end of each beam. Arrange 5 in a circular shape when viewed two-dimensionally,
After the filling material 4 is hardened, the tension material 5 is strongly tensioned to generate an inward centripetal force to crimp the beam and the column.

In the above invention, the column is a concrete-filled steel tubular column 1 having a circular cross section or a concrete column, and the beam is a precast concrete beam 3 into which a prestress is introduced.
The beam 3 is erected by mounting the joint end 2 on the bracket 6 fixed to the beam mounting position of the pillar 1, and the PC steel wire 5 as a tensile member is attached to the joint end 2 of the beam. It is characterized in that it is inserted and arranged in a sheath buried in advance, and that the filler is injected into the joint 7 between the joint ends of the beam 3 after the crimping due to the tension of the PC steel wire is completed. To do.

In the above invention, a plurality of the tension members 5 are arranged in a substantially horizontal circular shape at intervals in the height direction of the joint end portion 2 of the beam, or in the joint end portion 2 of the beam. It is also characterized in that one or a plurality of spiral threads are arranged in a multi-threaded shape with a suitable lead angle in the height direction. In the above invention, the tensile member 5 is arranged at the joint end 2 of the beam,
The notch 8 is preformed in the height direction for performing the tensioning and crimping process, and the notch 8 is filled with concrete 9 after the tension member 5 is arranged and the tensioning and crimping process is performed. And

The joint end of the beam in each of the above inventions is also characterized in that it is formed of a steel aggregate 2'embedded in the end of the precast concrete beam.

[0009]

When a tension force is introduced into the tension members 5 arranged in a circular shape when viewed two-dimensionally, an inward centripetal force equal to that when the barrel of the barrel is tightened is generated, which means that the joint ends of the beams 3 are joined. The two are equally tightened to generate a crimping force between the column 1 and the column 1 having a round cross section, and a frictional force is generated to produce an integrated joining (crimping) effect. Therefore, the cross-sectional shape of the column 1 and the joint end portion 2 of the beam is
It must have a round cross section based on a circular shape. The above-mentioned crimping action is mathematically shown as follows.

Considering per unit height, the central angle per unit length of the circumference is θ, and the centripetal force P ₀ per unit length generated by the tension force P introduced into the tension member 5 is P ₀ = It is calculated by P × sin (1 / 2r) (hereinafter, referred to as an equation). However, r is the radius of curvature of the tension member 5 having a round shape. Therefore, the bending moment acting on the crimping surface of the beam and the column is M, the shearing force acting on the crimping surface is Q, and the friction coefficient between steel and concrete is μ, and the shape shown in FIGS. Consider a case where the column-beam frame is subjected to pressure treatment by tensioning the tension members 5 arranged in four stages above and below. The tension force P ₁ per unit area required to withstand the shearing force Q acting on the crimping surface is Q = A × P _{1 where} A is the crimping area.
It is calculated by P ₁ = Q / A · μ (hereinafter referred to as the formula), which is a modification of the formula of × μ. For example, when the outer diameter of the pillar 1 is 80 cm, the height dimension of the joint end portion 2 of the beam is 75 cm, and the shearing force Q is 100 tons, the tension P ₁ required is 35.4 kg / cm ² from the above formula. Is calculated. The tension P required for the tensile member 5 per unit height is calculated as 4248 kg / cm from the above formula. Therefore, the effective tension P _e per PC steel wire is calculated to be 79.65 tons based on P = 4280 kg / cm 2 obtained as described above. On the other hand, the tensile strength P _y of a PC steel wire obtained by bundling 11 strands of steel stranded wire having an outer diameter of 12.7 is 17
It is 4.9 tons. The friction loss of the tension force and the reduction coefficient of the set loss are set to 0.65, the effective rate of the tension force is set to 0.85, and when the tension force is introduced, it does not exceed 85% of the tensile strength P _y of the PC steel wire. Since these values (0.65 × 0.85 × 0.85) are used for the tensile strength P _y
= 174.9 tons, the effective tension force P _e ′ obtained is 82.2 tons. Since this numerical value P _e ′ is larger than the effective tension P _e = 79.65 tons, the effectiveness and practicality of the present invention are confirmed.

[0011]

EXAMPLE An example of the present invention shown in the drawings will be described below.
1 and 2 showing the first embodiment, an angle bracket 6 is fixed to a beam mounting position on the outer peripheral surface of a concrete-filled steel tubular column 1 having a circular cross section and a diameter of 80 cm, and the bracket 6 is mounted on the bracket 6. It shows a configuration in which each precast concrete beam 3 is erected by mounting the joint end 2 of the beam. The precast concrete beam 3 has a size of about 75 cm and is also a prestressed concrete beam with prestress introduced. The joint end 2 of each beam is
As is apparent from FIG. 1, the outer shape of the column 1 (equal to the outer diameter).
The diameter of the circle is larger than the thickness required for crimping and joining (in the case of Fig. 1, the outer diameter of the joining end is about 140 cm. Therefore, the thickness of the joining end is 30 cm.) 45 for each
It has a shape equal to a quarter of the angle. Inside the vertical cross-section of each joint end 2 of the above-mentioned shape, there are 4 steps at an equal pitch of about 20 cm in the height direction (see FIG. 2, but the number of steps is not limited to this), and each is in the horizontal direction. A tensile member 5 is arranged in a circular shape having a diameter of about 120 cm (circular shape concentric with the pillar) so as to commonly pass through the respective joint ends. Specifically, the sheath tube is embedded in advance inside the cross section of the joint end portion 2 in the above-described arrangement, and the outer diameter of the tensile member is 12.
A PC steel wire 5 in which 11 7-strands of 7 mm are bundled is used, which is sequentially inserted into the above-mentioned sheath tube after constructing each beam. In order to facilitate the work of inserting the PC steel wire 5 into the sheath tube, and the work of introducing tension and crimping, a notch 8 having a right-angled triangular planar shape is formed at the end face of the joining end 2. The PC steel wire 5 arranged in a circle has a plane perpendicular to the tangential direction on both sides in the tangential direction (a tangent line extending from the intersection of the PC steel wires arranged in a circle in a hachimaki shape). Formed (see FIG. 1).

The work of tensioning and crimping the PC steel wire 5 is performed by injecting a filler such as joint mortar into the gap 4 between the abutting surfaces of the joint end 2 of the beam and the concrete-filled steel pipe column 1,
Do it after it hardens. The procedure is to crimp 10 one end of the PC steel wire on the right-angled surface of one of the notches 8 of the pair of the notches 8, 8 that face each other on both sides in the tangential direction of the PC steel wire 5. A tensioning jack (center hole jack) 11 is installed on the right-angled surface of the other notch 8 and a predetermined tension force is introduced by operating the jack 11 to perform a crimping process. In this way, after all the PC steel wires 5 have been tensioned and pressure-bonded, each notch 8 is filled with a filler 9 such as mortar.
To shape the shape. In addition, the work of tensioning and crimping the PC steel wire 5 arranged in four steps in the height direction of the joining end portion 2 is shown in FIG.
It is convenient that the tension force can be equalized by adopting a configuration in which the direction is changed by 90 ° step by step in the forward direction when viewed in the direction of. After the above-mentioned tensioning and pressure bonding work is completed, a filler such as mortar is also injected into the joint 7 between the joint ends 2 and 2. Then, the slab 12 is constructed on each beam 3.

[Second Embodiment] The second embodiment shown in FIGS. 4 and 5.
Although the basic structure of the embodiment is the same as that of the first embodiment, it is characterized in that the tension members 5 are arranged in a spiral shape having an appropriate lead angle in the height direction of the joint end portion 2 of the beam.
FIG. 4 shows that a typical PC steel wire 5 has a spiral arrangement in which it extends over a pair of upper and lower notches 8 to be tensioned while the PC steel wire 5 makes one revolution.
In FIG. 5, four PC steel wires 5 are arranged in a vertical direction of the joining end portion 2 in a so-called four-threaded form with a proper pitch, and the start and end positions of the spiral are seen in a plan view. And 90 ° apart from each other in the forward direction to perform tensioning and crimping processes.

[Third Embodiment] FIGS. 6 and 7 show a steel frame in which the joint end portion of each beam described in the above embodiment is formed from steel, cast iron or cast steel, or forged steel or other metal. It is made of a material (metal material) 2 ′, which is integrally embedded in the end portion of the precast concrete beam 3.

[0015]

The joint construction method of the precast concrete beam and the round cross-section column according to the present invention is such that there is no reinforcing bar, anchor rebar or PC steel wire for joining in the so-called column panel zone. First, the structure of the joint is significantly simplified. In addition, since there is no PC steel wire or the like penetrating the pillar, there is no need for machining (piercing, etc.) of the pillar (steel pipe), which facilitates machining. Furthermore, since most of the work of joining the columns and beams on site is the work of tensioning and crimping the tension material, the work on site can be performed efficiently and the construction period can be shortened.

In addition, since an isotropic crimping method for tightening in a round shape is also used for a circular cross-section column which is isotropic in plan view, it is mechanically clear and rational, and the design Is easy.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of the construction method of the present invention.

FIG. 2 is a sectional view taken along the line 2-2 of FIG.

FIG. 3 is a perspective view showing a part of a precast concrete beam used in the above embodiment.

FIG. 4 is a perspective view showing a second embodiment of the construction method of the present invention.

FIG. 5 is a sectional view showing a simplified example of the above embodiment.

FIG. 6 is a plan view showing a third embodiment of the construction method of the present invention.

7 is a sectional view taken along the line 7-7 of FIG.

[Explanation of symbols]

 1 Column 2 Joined End 3 Precast Concrete Beam 4 Gap 5 Tensile Material 6 Bracket 7 Joint 8 Notch 2 ′ Steel Aggregate

Claims (6)

[Claims] 1. A joint end portion having a shape equal to that obtained by dividing a round shape, which is larger than the outer shape of the pillar by a thickness dimension required for joining, at a beam mounting position of the pillar having a round cross section. A precast concrete beam is erected with each of the joint ends abutting on the outer peripheral surface of the column, a filler is injected into the gap between the joint end and the column, and the inside of the cross section of the joint end of each beam Arranging tensile members penetrating in common in a circular shape when seen in a plan view, and after the filling material is hardened, the tensile members are strongly tensioned to generate an inward centripetal force to crimp the beam and column. The method of joining precast concrete beams to columns with round cross-sections, which is characterized by 2. The column according to claim 1 is a concrete-filled steel pipe column or a concrete column having a round cross section, and the beam is a pre-stressed precast concrete beam, and the beam is fixed to the beam mounting position of the column. Put the joint end on the bracket and erected it.
The C steel wire is inserted and arranged in a sheath previously embedded in the joint end portion of the beam, and after the crimping due to the tension of the PC steel wire is completed, a filler is added to the joint between the joint end portions of the beam. A method for joining precast concrete beams to columns with round cross-sections, which is characterized by injecting. 3. A precast concrete beam, wherein a plurality of the tensile members according to claim 1 or 2 are arranged in a substantially horizontal circular shape at intervals in a height direction of a joint end portion of the beam. Construction method of column and circular cross-section column. 4. The tensile member according to claim 1 or 2, wherein one is provided in a spiral shape with an appropriate lead angle in the height direction of the joint end of the beam,
Alternatively, a construction method for joining a precast concrete beam and a column having a round cross-section, characterized in that a plurality of threads are arranged in a multi-threaded shape. 5. A tensile member is arranged at the joint end portion of the beam according to claim 1 or 2 or 3 or 4, and a notch for pretensioning and tensioning is preformed in the height direction, A joining construction method for a precast concrete beam and a column having a round cross-section, characterized in that the notch is filled with concrete after arranging the material, performing the treatment of tension and pressure bonding. 6. The joint end of the beam according to claim 1, 2 or 3 or 4 or 5 is formed of a steel aggregate embedded in the end of the precast concrete beam.
Construction method of precast concrete beam and column with round cross section.