JP5404271B2 - Joint structure of reinforced concrete column and steel beam - Google Patents

Description

  The present invention relates to a reinforced concrete column steel beam structure joint part of a building and a civil engineering structure. By using a precast block made of ultra-high strength fiber reinforced concrete, the construction can be simplified, the cost can be reduced, and the strength of the joint part can be reduced. It is intended to improve.

  In a conventional reinforced concrete column steel beam (hereinafter referred to as “RCS”) structural joint, the stress exerted in the RCS structural joint is severe and stress concentration is unavoidable, so there are many reinforcing bars or reinforcements in the RCS structural joint. Reinforcement by etc. was necessary. For this reason, there is a problem that it takes a lot of work to construct the reinforcing bars for the RCS structure joint portion, and furthermore, since there are many reinforcing bars, it is difficult to place concrete.

  On the other hand, by using ultra-high-strength fiber reinforced concrete (hereinafter referred to as UFC) for reinforced concrete beam-column (hereinafter referred to as “RC column beam”) joints, it is possible to increase the strength and performance of RC beam-column joints. It has been found that there are merits such as being able to be reduced and reducing or removing reinforcing bars.

  Examples of prior art documents related to the column-beam joint structure as described above include inventions described in Patent Documents 1 to 3 and Non-Patent Documents 1 and 2, for example.

  In Patent Document 1, in a joint structure between a reinforced concrete column and a steel beam, a large number of stud bolts are planted on the upper and lower surfaces of the flange of the steel beam in the joint, and the concrete in the joint of the reinforced concrete column has high strength. The steel fiber reinforced concrete is used.

  Patent Document 2 discloses a metal joint for joining a reinforced concrete column and a steel beam having an H-shaped cross section. A web connecting plate that is fitted to the outer periphery of a steel beam joint position in a reinforced concrete column and that the steel beam is joined directly or indirectly to the outside, and a web connection plate that connects the inside of the joint pipe corresponding to the web joint position of each steel beam. And a stiffener that is formed in a ring shape having an inner periphery substantially similar to the bar arrangement contour of the column main reinforcement, and is joined to the flange joining position of the steel beam and the inside of the joining cylinder corresponding to the flange joining position.

  In patent document 3, the structure regarding the column beam junction part of the structure comprised by the column made from a reinforced concrete and a steel beam is shown. Two unit bonded steel plates are arranged in a cross shape on the flange joint of a steel beam of a reinforced concrete column, and the beam is fixed to the part protruding from the column of the unit bonded steel plate. It consists of a square columnar joint having one side equal to the width of the columnar and a trapezoidal beam joint extending on the two opposite sides of the columnar joint.

  A state in which a hole for filling concrete is drilled in the center of the column joint portion and two unit joint plates each having a column reinforcement insertion hole drilled in four corners of the column joint portion are fastened by fastening with bolts. It is the structure of the column beam joint part which has been arranged in piles.

  In Non-Patent Document 1, UFC element tests are shown in the structural performance of RCS joints using UFC, and it is confirmed that they have the necessary performance of compressive strength, tensile strength, and bending strength.

  Non-Patent Document 2 shows an experiment in which UFC is applied to a part of an RCS joint, and shows a hysteresis property excellent in deformation performance and a damage reduction effect.

JP 63-161234 A Japanese Patent Laid-Open No. 04-045446 JP 2000-008486 A

Nagai, Satoshi Kubota, Yoshikazu Takatsuki, Takashi Okayasu: “Structural performance of reinforced concrete columns and steel beam joints using ultra-high-strength fiber reinforced concrete, Part 1 Element test of ultra-high-strength fiber reinforced concrete”, 35th Japan Architectural Institute Conference Academic Lecture Summary, September 2008 Satoshi Kubota, Satoshi Nagai, Takashi Okayasu, Yoshikazu Takahata: “Structural performance of reinforced concrete column-to-steel beam joints using ultra-high-strength fiber reinforced concrete, Part 2 Partial frame tests of beam-to-column joints”, 35th Japanese Architecture Summary of academic conference annual conference, September 2008 Saxem Study Group, “Super High-Strength Fiber Reinforced Concrete“ SUQCEM ””, [online], [Search June 30, 2009], Internet <URL: http: / ・ www.suqcem.com/>

  As described above, the beam-column joint using fiber reinforced concrete is shown for the RCS structure and the RC column beam. However, since the proof strength must be able to withstand the stress concentration at the joint, It is a complicated construction that uses streaks and reinforcement hardware, and requires advanced technology, resulting in cost and time.

  Furthermore, it is difficult and troublesome to place UFC on a member having a complicated shape or bar arrangement such as an RCS structure joint or RC beam-column joint, and there is a high possibility that a filling defect will occur. Moreover, since UFC is expensive compared with normal concrete, it will also cost.

  The present invention aims to solve the above-mentioned problems in the prior art, and simplifies the construction by partially using a UFC precast (hereinafter referred to as PCa) block at the RCS structure joint. The purpose is to improve yield strength and reduce costs.

The invention according to claim 1 of the present application is a joint structure between a reinforced concrete column and a steel beam, in which a precast block using ultra-high-strength fiber reinforced concrete is installed so as to be in contact with the steel beam. It is a part structure, Comprising: The said precast block serves as the formwork of a column beam junction part, It is characterized by the above-mentioned.

  By using UFC having excellent deformability for the beam-column joint part of the RCS structure, it is possible to withstand stress concentration at the joint part, and there is little occurrence of cracking, and the proof stress of the joint part is improved. Moreover, if UFC made into PCa block is installed in a junction part, a reinforcement reinforcement can be reduced or eliminated, and it leads to simplification of construction.

  For example, “Sucsem” shown in Non-Patent Document 3 is listed as UFC (Registered Trademark No. 4915838). “Suxem” is composed of premix binder, aggregate, special steel fibers for reinforcement, high-performance water reducing agent and water.

Standard formulation, the water binder ratio of 15%, the flow value 250 mm, air volume of 2.0%, water 195 kg / m ^3, a premix binder 1287kg / m ^3, the aggregate 905 kg / m ^3, superplasticizer 32. It is 2 kg / m ³ , 137.4 kg / m ³ (1.75 vol%) of special steel fibers for reinforcement, and the design standard strength is 180 N / mm ² . However, in the present invention, the UFC is not limited to “sucsem”, and if the same UFC is used, the effect of the present invention can be expected.

  In a joint structure of a reinforced concrete column and a steel beam according to claim 1, the precast block using the ultra high strength fiber reinforced concrete is provided with an upper surface of an upper flange of the steel beam and / or a lower surface of a lower flange. And the reinforced concrete columns are in contact with each other.

  A bearing pressure is applied to the upper surface of the upper flange of the steel beam and the lower surface of the lower flange, where the steel beam flange and the reinforced concrete column are in contact with each other, and the damage in the beam-column joint is increased. In order to suppress this damage, the UFC PCa block is locally arranged to prevent local destruction and improve the performance of the joint. In addition, the expensive UFC is not used as a whole, but the cost can be reduced by using it in a limited manner.

  The joint structure of a reinforced concrete column and a steel beam according to claim 1 or 2 according to claim 3, wherein one surface or a plurality of surfaces of the precast block using the ultra high strength fiber reinforced concrete are in contact with the steel beam. It is characterized by being arranged between the flanges or around the web.

  Installing the UFC PCa block so that it touches between the flanges of the steel beam or the web means that the UFC PCa block is installed just in contact with the steel beam. It is easy to do and shortens work time and improves work efficiency.

  By installing the UFC PCa block so as to be in contact with one or more surfaces of the steel beam, local destruction due to the bearing pressure at the position where the steel beam is in contact can be prevented as in the second aspect.

  In the case of using normal concrete and formwork, there was a problem of workability such as the end of the concrete forming the column surface being chipped or cracked at the time of demolding.

  Therefore, when the UFC PCa block is used as a buried formwork for the beam-column joint, the formwork that has been required up to now is no longer required, so that the demolding work is eliminated, and the above problems can be improved. It is possible to improve the finish of the surface of the beam-column joint and the work efficiency, and to reduce the cost.

The invention according to claim 4 is a joint material structure of a reinforced concrete column and a steel beam according to claim 1, 2 or 3 , wherein the precast block is a tension material that penetrates the precast block using the ultra high strength fiber reinforced concrete. Is fixed to a steel beam.

  The tensioning material penetrates the UFC PCa block and is crimped to the steel beam, so that the tensioning material not only complements the role of the reinforcing bar, but also the friction between the steel beam and the PCa block, the steel beam and the UFC PCa block Stress transmission is possible.

  Furthermore, since the PCa block is made of UFC, it is difficult to cause split breakage occurring at the fixing portion of the tendon material, and it is possible to simplify the fixing hardware of the tendon material that has been necessary in the past, leading to cost reduction. Alternatively, the fixing hardware can be replaced with a normal nut and washer.

  Since this invention becomes the above structures, the following effects are acquired.

(1) By placing UFC PCa blocks locally, it is possible to withstand stress concentration at the joint. Since UFC is excellent in deformation performance, cracks are less likely to occur, the proof stress of the joint can be improved, and effective reinforcement can be achieved. Further, the proof stress can be maintained even if the reinforcing bars at the joint are reduced.

(2) By partially using the UFC PCa block, the amount of expensive UFC used can be reduced and the cost can be reduced. In addition, the construction is easy and the work efficiency is improved.

(3) By embedding UFC PCa block into a buried formwork, not only the reinforcement effect of the joint, but also the cost reduction by eliminating the normal formwork, workability and work efficiency, column beam joint Improved finish.

(4) By creating a column beam joint by combining UFC PCa block and tension material, the PCa block can be crimped to the steel beam by the tension material that penetrates the PCa block. Stress transmission to the block is possible. Since it is not necessary to place concrete at the beam-column joint, the work of the beam-column joint can be carried out simply, quickly and cleanly.

(5) Since the tendon replaces the reinforcing bar at the joint, the amount of reinforcing bar can be reduced. In addition, since the PCa block is made of UFC, it is difficult to cause split fracture occurring in the fixing portion of the tension material, and it is possible to simplify the fixing hardware of the tension material, which has been conventionally required, and to reduce the cost.

It is a perspective view at the time of arranging a UFC PCa block under a steel beam in a column beam junction part concerning the present invention. It is a perspective view at the time of arranging the PCa block of UFC so that it may contact a web between the upper and lower flanges of a steel beam in the column beam junction concerning the present invention. It is a perspective view at the time of arrange | positioning the L-shaped UFC PCa block so that it may contact | connect a web between the upper and lower flanges of a steel beam in the column beam junction part which concerns on this invention. It is a perspective view at the time of arranging the B type UFC PCa block so that it may contact a web between the upper and lower flanges of a steel beam in the column beam junction part concerning the present invention. In the beam-column joint according to the present invention, UFC PCa blocks are used as an embedded formwork, (a) is a perspective view of a steel beam, (b) is a perspective view of an embedded formwork, and (c) is a perspective view. The top view when an embedded formwork is installed in a steel beam, (d) is a front view at the time of (c). It is an example which utilized the PCa block of UFC for an embedded formwork in the column beam junction concerning the present invention, (a) is a perspective view of a steel beam, (b) is a perspective view of an embedded formwork for side, (c) ) Is a perspective view of an embedded form for upper and lower surfaces, and (d) is a front view when the embedded form is installed on a steel beam. It is an example which utilized the PCa block of UFC for an embedded formwork in the column beam junction concerning the present invention, (a) is a perspective view of a steel beam, (b) is a perspective view of an embedded formwork for side, (c) ) Is a perspective view of an embedded form for upper and lower surfaces, and (d) is a front view when the embedded form is installed on a steel beam. It is an example utilized for the embedded formwork in the column beam joint according to the present invention, (a) is a perspective view of a steel beam, (b) is a perspective view of a side embedded formwork, and (c) is an upper and lower surface embedded type. The perspective view of a formwork, (d) is a front view when an embedded formwork is installed on a steel beam. FIG. 2 is an example in which a UFC PCa block is crimped with a tension material in a column beam joint according to the present invention, (a) is a perspective view of a steel beam, (b) is a perspective view of a PCa block, and (c) is a steel frame. It is a perspective view when attaching a PCa block to a beam. FIG. 2 is an example in which a UFC PCa block is crimped with a tension material in a column beam joint according to the present invention, (a) is a perspective view of a steel beam, (b) is a perspective view of a PCa block at an outer peripheral portion, and (c) ) Is a perspective view of a PCa block installed inside, and (d) is a perspective view when the PCa block is installed. In the beam-column joint according to the present invention, an example in which a recess of a column-joining cotter is attached to the upper portion of the beam-column joint. In the beam-column joint according to the present invention, the convex portion of the column-joining cotter is attached to the upper portion of the beam-column joint.

  Hereinafter, embodiments of the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below.

  FIG. 1 is a perspective view when a UFC PCa block 11 is arranged under a steel beam 3 having an H-shaped cross section in a column beam joint 1 according to the present invention. In addition, although the steel beam 3 of H type steel is illustrated in all the figures, angle steel and lip groove steel may be used besides H type steel, and the kind of steel beam 3 is not ask | required.

  By installing the UFC PCa block 11 formed in a rectangular parallelepiped at the four positions on the lower surface of the lower flange 3c of the steel beam 3, the lower flange 3c has a function of preventing a bearing failure at a portion in contact with the reinforced concrete column 2. The construction is very easy because the rectangular parallelepiped PCa block 11 is simply incorporated into the reinforced concrete column 2.

  FIG. 2 is a perspective view in the case where the UFC PCa block 11 is disposed between the upper and lower flanges (3a, 3c) of the steel beam 3 so as to contact the web 3b in the column beam joint 1 according to the present invention. As in FIG. 1, the UFC PCa block 11 made in a rectangular parallelepiped is installed between the upper flange 3a and the lower flange 3c of the steel beam 3 so as to be in contact with the web 3b, so that stress transmission from the steel beam 3 is expected. In addition, by preventing deformation of the steel beam 3 itself, local destruction of the concrete around the steel beam 3 can be prevented.

  FIG. 2 shows an example in which two rectangular parallelepipeds are combined and installed so as to be L-shaped. However, as shown in FIG. 3, the PCa block 11 is made L-shaped from the beginning, A method of fitting between the upper and lower flanges (3a, 3c) so as to contact the web 3b may be used.

  FIG. 4 is a perspective view in the case where the UFC PCa block 11 made in a B shape is arranged so as to be in contact with the web 3b between the upper and lower flanges (3a, 3c) of the steel beam 3 in the column beam joint 1 according to the present invention. FIG. By making the UFC PCa block 11 B-shaped, the UFC PCa block 11 can be formed from the portion in contact with the web 3b between the upper flange 3a and the lower flange 3c of the steel beam 3 to the portion not in contact with it. The bearing failure between the upper and lower flanges (3a, 3c) of the beam 3 and the local failure of the concrete around the steel beam 3 can be prevented at the same time, which is a very effective reinforcement.

  Although FIGS. 1 to 4 show rectangular parallelepiped, L-shaped, and U-shaped UFC PCa blocks, the present invention is not limited to these specifications.

  FIG. 5 is an example in which a UFC PCa block is used for the embedded formwork 12 in the beam-column joint 1 according to the present invention, where (a) is a perspective view of the steel beam 3 and (b) is an embedded formwork 12. (C) is a top view when the embedded formwork 12 is installed in the beam-column joint 1, and (d) is a front view at (c).

  The embedded form 12 in FIG. 5B shows an L-shaped block in which a recess is created so that it can be fitted into the upper flange 3a and the lower flange 3c of the steel beam 3. FIG. When the embedded form 12 is fitted into the steel beam 3 having the H cross section shown in FIG. 4 from four directions, the cross of the steel beam 3 is surrounded by the embedded form 12 of the UFC PCa block (FIG. 5C). reference). At the same time, an opening (21 + 22) squarely surrounded by the embedded form 12 and the upper and lower flanges (3a, 3c) is formed, and the reinforcement of the main reinforcement of the reinforced concrete column 2 can be applied from that portion, and the concrete can be placed.

  Similarly, FIG. 6 shows an example in which a UFC PCa block is used as an embedded formwork in the column beam joint 1 according to the present invention. An L-shaped PCa block provided with notches that fit into the upper flange 3a and the lower flange 3c of the steel beam 3 is prepared as the side embedded form 13 (see FIG. 6B). An upper and lower surface embedded form 14 is provided so as to sandwich the embedded form 13 and the steel beam 3 from above and below (see FIGS. 6C and 6D).

  Similarly to FIG. 5, the main reinforcing bars of the reinforced concrete column 2 can be arranged and four openings (21 + 22) where concrete can be placed can be provided. Further, as can be seen from FIG. 6D, by providing the upper and lower surface embedded molds 14 above and below the steel beam 3, it is possible to enhance the effect of preventing the bearing failure caused by the steel beam 3.

  Similar to FIG. 6, a pattern in which a side embedded form 13 and a top and bottom embedded form 14 are provided on the steel beam 3 is shown in FIGS. 7 and 8.

  As shown in FIGS. 5 to 8, when the UFC PCa block is used as the embedded formwork of the column beam joint 1, the formwork that has been required up to now is not necessary, and the cost can be reduced. In addition, when using normal concrete and formwork, there was a problem in workability and work efficiency such as the end of the concrete forming the column surface being chipped or cracked when demolding. The UFC PCa block is excellent in deformation performance and hardly cracks. Therefore, when used as an embedded formwork, the problems such as the workability and work efficiency as described above, and the finishing of the column surface are improved. Moreover, not only the effect as an embedded formwork but the effect which prevents the local destruction of the concrete around the steel beam 3 and the bearing failure of the upper and lower sides of the steel beam 3 can be expected at the same time.

  9 and 10 show an embodiment in which the UFC PCa block 11 is pressure-bonded to the steel beam 3 with a tension material. FIG. 9A shows a steel beam 3 in which a tension material hole 4 is formed in the web 3b, and a total of eight holes are formed in the cross portion. FIG. 9B shows a perspective view seen from the inside and a perspective view seen from the outside of the PCa block 11 installed so as to surround the cross portion.

  The PCa block 11 has three holes 22 for penetrating the reinforced concrete column 2 main bars above and below the PCa block 11 (Z direction), and a tension material is attached in the X direction and the Y direction so that the side surfaces of the PCa blocks 11 can be crimped. Four tension material holes 23 for passing through the upper and lower flanges 3a and 3c of the steel beam 3 were provided on the upper and lower sides.

By inserting the PCa block 11 from the four directions of the steel beam 3, it is possible to join the shape as shown in FIG. 9C, and the tension material penetrates the tension material hole 23 in the X direction and the Y direction. The steel beam 3 and the PCa block 11 or the PCa block 11 are pressure-bonded to each other.
Examples of the tension material mentioned here include PC steel bars, PC steel materials, piano wires, and other new materials.

  FIG. 10 shows an example in which the PCa block 11 shown in FIG. 9B is divided into an internal PCa block 15 and an outer peripheral PCa block 16 (see FIGS. 10A and 10B). Compared to FIG. 9, the number of blocks of the PCa block 11 is increased, but it is not necessary to create a notch portion for fitting the upper and lower flanges 3 a and 3 c, so that the PCa block 11 can be easily created, The installation will also be easier.

  As in FIG. 9, the PCa blocks 15 and 16 are provided with holes for column main bars 22 and tension members 23, respectively. First, the L-shaped internal PCa block 15 shown in FIG. 10C is fitted between the upper and lower flanges 3a and 3c, and is surrounded by the external PCa block 16 shown in FIG. It is formed in the shape shown in d).

  9 and 10, not only the tension material complements the role of the reinforcing bar of the reinforced concrete column 2 but also the stress transmission between the steel beam 3 and the UFC PCa block by friction with the steel beam 3. Make it possible.

  Since the PCa block is made of UFC, it is difficult for split fracture to occur at the fixing portion of the tension material, and the fixing hardware for the tension material, which has been conventionally required, can be simplified. Or, a normal nut and washer can be substituted, and the cost can be reduced.

  In FIG. 11, by providing a concave portion on the upper surface of the PCa block 11 and providing a convex portion in FIG. 12, it is possible to achieve integrity with the reinforced concrete column 2 and transmission of a shearing force.

  The present invention effectively uses the UFC PCa block, and by applying it to the column beam joint of a reinforced concrete column steel beam, the construction becomes simple and economical, and the proof stress can be further improved. .

DESCRIPTION OF SYMBOLS 1 ... Column beam junction 2 ... Reinforced concrete column 3 ... Steel beam 3a ... Steel beam upper flange 3b ... Steel beam web 3c ... Steel beam lower flange 4 ... Hole for tension material 11 ... Ultra high strength fiber reinforced concrete block (PCa of UFC) block)
DESCRIPTION OF SYMBOLS 12 ... Embedded form 13 ... Side embedded form 14 ... Top and bottom embedded form 15 ... Internal block 16 ... External block 21 ... Concrete placing hole 22 ... Column main reinforcement hole 23 ... Tensile material hole

Claims (4)

A joint structure between a reinforced concrete column and a steel beam in which a precast block using ultra-high-strength fiber reinforced concrete is installed in contact with the steel beam at the joint between the reinforced concrete column and the steel beam. A joint structure between a reinforced concrete column and a steel beam, which also serves as a formwork for the beam joint.   The precast block using the ultra high strength fiber reinforced concrete is installed in a portion where the upper surface of the upper flange of the steel beam and / or the lower surface of the lower flange and the reinforced concrete column are in contact with each other. Structure of reinforced concrete columns and steel beams.   The one or more surfaces of the precast block using the ultra-high-strength fiber reinforced concrete are in contact with the steel beam, and are arranged between the flanges of the steel beam or around the web. Joint structure of reinforced concrete column and steel beam. 4. A reinforced concrete column and a steel beam according to claim 1, 2 or 3 , wherein the precast block is fixed to a steel beam with a tension material penetrating the precast block using the ultra high strength fiber reinforced concrete. Joint structure.

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