JP2005180100A - Method of reinforcing joint of column and beam for shearing and reinforced joint structure for shearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of reinforcing the joint (of a beam-penetrating type) of a column made of reinforced concrete or steel-frame reinforced concrete and beams made of steel-frame, steel-frame reinforced concrete or steel-frame concrete, using reinforcing bars for shearing, and provide the reinforced joint structure of a column and beams. <P>SOLUTION: Steel-frame beams have top and bottom flanges in vertical section. Welded metal meshes or reinforcement grids are used as reinforcing bars for shearing. From a plan view of this joint of column and beams, welded metal meshes surround the external circumference of column's main reinforcements, its vertical length is housed within the top and bottom flanges of each beam and its lateral ends draws near each two adjacent steel-frame beams. At least one vertical reinforcing bar at both ends of the welded meshes is located within an area of the top and bottom flanges of adjacent beams to be filled with concrete placed. The welded metal meshes etc. is installed by connecting them with main vertical reinforcements etc. using wires. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention may be a reinforced concrete structure (hereinafter sometimes abbreviated as RC structure) or a steel-framed reinforced concrete structure (hereinafter sometimes abbreviated as SRC structure) and a steel structure (hereinafter referred to as S structure). ) Or a steel beam reinforced concrete structure or a steel-concrete structure (hereinafter referred to as SC structure) beam-to-column joint with a beam, particularly a beam penetration type column beam joint with a reinforcing method and structure It belongs to the technical field.

  Conventionally, as a reinforcing method and a reinforcing structure by a shear reinforcing bar of a column beam joint portion between an RC or SRC column and an S or SRC or SC structure beam, as illustrated in FIG. A hole is made in the web 4a of each beam steel frame 4 of the four beams 3 joined in a cross-shaped arrangement with the steel frame 2 of the pillar 1 as the center, and a total of four L-shapes penetrating the holes. The reinforcing bars 6 are arranged in a closed shape that surrounds the outer periphery of the column main bars 5 and parts thereof are wrapped together, and the wrap portions 7 are joined together by field welding to assemble and install shear reinforcement bars (hoop bars). It was.

However, in the above-described conventional technology, it is necessary to make a hole in the web 4a of the steel frame 4, and a step of drilling is required. Moreover, if a hole is made, a cross-sectional defect of the steel frame 4 occurs, which causes a reduction in the shear strength of the beam 3. In addition, the work of assembling the L-shaped rebars 6 in a closed shape surrounding the outer periphery of the column main bar 5 one by one and wrapping them together is extremely cumbersome and time-consuming, and on-site welding of the lap part 7 is required. Welding work on site is more susceptible to variations in quality compared to welding at the factory, is easily influenced by weather conditions, and has a great influence on the work schedule. Moreover, since the beam-column joint is naturally a place where the amount of bar arrangement is large and crowded with rebars and steel frames, there are many obstacles to the welding work of the lap part 7, and in some cases the welding work itself is impossible. There are also many.
Under such circumstances, there has been a strong demand for the development of a reinforcement method and a reinforcement structure that do not require on-site welding to reinforce the beam-column joint with shear reinforcement.

As a prior art of a reinforcing method and a reinforcing structure that do not require the on-site welding, the following Patent Document 1 is provided with a long bolt that passes through each web of a pillar steel frame having a cross-shaped horizontal cross section, and a shear reinforcing bar. As described above, there is disclosed a reinforcing structure for a column beam joint in which flat steel is formed in an L shape in plan view and attached to the long bolt to form a closed shape.
In Patent Document 2, a through hole is provided in each web of a columnar steel frame having a cross-shaped horizontal cross section, and a L-shaped or U-shaped shear reinforcing bar in plan view is passed through the through hole, and the same through hole is formed from the opposite side. There is disclosed a reinforcing structure for a beam-column joint in which a wedge is driven and fixed at an intersection with a shear reinforcing bar that passes through.
In Patent Document 3, a through hole is provided in each web of a columnar steel frame having a cross-shaped horizontal cross section, and a L-shaped or U-shaped shear reinforcement bar in a plan view is arranged in a stepped manner up and down to the through hole. Further, a reinforcing structure of a column beam joint in which each end is fastened with a nut is disclosed.

In Patent Document 4, a through hole is provided in each web of a columnar steel frame having a cross-shaped horizontal cross section, and a hook-shaped connecting line is provided in advance in the through hole, and the plan view is L-shaped or U-shaped. A reinforcing structure of a beam-column joint portion in which a shear reinforcing bar is connected with the connecting bar is disclosed.
Patent Document 5 discloses a column beam joint portion in which a horizontal hole is provided with a through hole in each column steel frame and a wire rope passed through the through hole is wound around the outer circumference of the column main bar and spirally arranged. A reinforcing structure is disclosed.

  In Patent Document 6, a necessary number of bolt holes are formed in each column steel beam or beam steel web having a cross-sectional horizontal cross section, and a welded wire mesh (or also referred to as a welded rebar) is used as a shear reinforcement. Are formed in an L shape in plan view, and at both ends thereof, mounting plates such as angles are integrated in the vertical direction, and a plurality of bolts passing through the bolt holes of the beam steel web and A reinforcing structure of a beam-column joint part fastened with a nut and arranged is disclosed.

  In Patent Documents 7 and 8, a longitudinal bar is fixed between upper and lower flanges at a position slightly away from the web of the beam steel frame, while the shear reinforcing bar is formed in an L shape in plan view and both ends thereof. Reinforcement of the beam-to-column joint formed by providing hook-shaped locking portions on the top, arranging a plurality of shear reinforcing bars at intervals in the vertical direction, and locking the locking portions at both ends to the vertical bars A structure is disclosed.

Japanese Utility Model Publication No. 63-21604 Japanese Utility Model Publication No. 63-21606 Japanese Utility Model Publication No. 63-21607 No. 6-7122 Japanese Utility Model Publication No. 3-44881 Japanese Utility Model Publication No. 5-20802 Japanese Patent No. 2,706,827 Japanese Patent No. 2903189

All of the techniques disclosed in Patent Documents 1 to 8 described above are a reinforcing method and a reinforcing structure that do not require in-situ welding to reinforce the column beam joint with the shear reinforcement bars. However, any shear reinforcement method and reinforcement structure adopts a structure in which holes are made in the column steel or beam steel web or flange, and the shear reinforcement is fixed using bolts, nuts, or connecting bars. Yes. Therefore, a number of drilling processes on the steel frame are indispensable conditions, which requires a lot of man-hours, and the problem that a cross-sectional defect is caused in the steel frame and the reduction in the shear strength of the beam cannot be denied.
In addition, a process of assembling the shear reinforcement bars through the holes one by one is also necessary, which requires a lot of labor and time. In addition to consuming such parts for fixing by using bolts, nuts and connecting bars as a means to fix the shear reinforcement bars, it is still necessary to thread the shear reinforcement bars directly. In short, there are disadvantages that the work at the site is cumbersome and takes a long construction period and cost.

  The object of the present invention is not to require any on-site welding, and it is not necessary to drill holes in steel webs and flanges. (Or also called welded reinforcing bars) can be used to eliminate troublesome assembly work at the site, and anyone can easily and accurately arrange the welded wire mesh by means of binding to the longitudinal main bars of the column. Shear reinforcement of column beam joints that can be worked, has excellent workability, quality, and accuracy, and has no need for fixing with bolts, nuts or connecting bars, etc., and can significantly reduce the work period and cost. It is to provide a shear reinforcement method by a muscle and a shear reinforcement structure.

As means for solving the above-mentioned problem, a shear reinforcement method using a shear reinforcement bar of a beam-column joint according to the invention described in claim 1 is:
In a method for shear reinforcement of a column beam joint between a reinforced concrete or steel reinforced concrete column 1 and a steel or steel reinforced concrete or beam 3 of a steel concrete structure,
The steel frame 4 of the beam 3 has upper and lower flanges 4b and 4b in a vertical section,
As the shear reinforcement, a welded wire mesh 16 or a reinforcing bar grid (hereinafter sometimes abbreviated as a welded wire mesh 16 or the like) is used, and the welded wire mesh 16 or the like is an outer periphery of the column main reinforcement 5 when the column beam joint is viewed in plan view. The upper and lower flanges 4b, 4b of the beam steel frame 4 are shaped so as to have a length close to the web 4a of the beam steel frame 4 within the area of the section blocked by the webs 4a, 4a of the beam steel frame 4. Providing at least one longitudinal streak 17 in the region where the concrete restrains the concrete;
The above-described welded wire mesh 16 and the like are installed by means such as binding to the longitudinal main reinforcement 5 of the column 1.

  The invention described in claim 2 is the method of shear reinforcement of a beam-column joint according to claim 1, wherein the upper and lower flanges 4b, 4b of the beam steel frame 4 of the welded wire mesh 16 or the reinforcing bar lattice restrain the concrete. A portion that falls within the region is bent in the same direction as the web 4a of the beam steel frame 4, and at least one vertical bar 17 is provided in the bent portion.

The invention described in claim 3 is the method for shear reinforcement of a beam-column joint according to claim 1 or 2,
A restraint assisting means such as a stud 20 for restraining concrete is provided on the web 4a of the beam steel frame 4.

The invention described in claim 4 is the shear reinforcement method for a column beam joint according to any one of claims 1 to 3,
A plurality of vertical bars 17 are intensively provided inside and outside a portion of the welded wire mesh 16 or a reinforcing bar lattice in which the upper and lower flanges 4b and 4b of the beam steel frame 4 are housed in a region where the concrete is constrained.

The shear reinforcement structure of the beam-column joint according to the invention described in claim 5 is:
In the shear reinforcement structure of the column beam joint between the reinforced concrete or steel reinforced concrete column 1 and the steel or steel reinforced concrete or beam 3 of the steel concrete structure,
The steel frame 4 of the beam 3 is configured to have flanges 4b and 4b at the top and bottom in a vertical section,
As the shear reinforcement bar, a welded wire mesh 16 or a reinforcing bar lattice is used. The welded wire mesh 16 surrounds the outer periphery of the column main bar 5 in a plan view of the column beam joint, and the webs 4a, 4a of the beam steel frame 4 are surrounded. The beam steel frame 4 has a length close to the web 4a of the beam steel frame 4, and at least one of the upper and lower flanges 4b and 4b of the beam steel frame 4 in a region where the concrete is constrained. The vertical stripes 17 are provided,
The welded wire mesh 16 and the like are installed by means such as binding to the longitudinal main reinforcement 5 of the column 1 or the like.

According to the first to fifth aspects of the present invention, the welding rebar 16 or the like is simply connected to the main reinforcing bar 5 of the column 1 without the need for on-site welding at all, as well as the need for fixing and joining with bolts, nuts, connecting bars, or the like. Since the bar arrangement is performed by means of binding to the tie, the construction is simple and easy, the workability is greatly improved, and the construction period can be shortened. In addition, it is unnecessary to drill holes in the webs and flanges of the steel frames 2 and 4 and there is no problem of cross-sectional defects, so that the shear strength of the beam 3 can be prevented from being lowered.
As a shear reinforcement, it is a commercially available factory product with high quality and high accuracy, such as a welded wire mesh 16 or a rebar lattice, or a combination of reinforcing bars bound in a lattice shape (hereinafter sometimes referred to as a welded wire mesh 16 or the like as a generic term). )), It is possible not only to greatly eliminate the troublesome work of assembling the reinforcing bars on site, but also to facilitate the arrangement of the reinforcing bars, even if you are not an expert.
In addition, the welded wire mesh 16 and the like need only be lightly stopped to the extent that it can withstand concrete placement by simple means such as binding to the longitudinal main bar 5 of the column 1, and anyone can easily perform bar arrangement work and is excellent in workability. .
Nevertheless, since the upper and lower flanges 4b, 4b of the beam steel frame 4 are provided with at least one vertical bar 17 in the region where the concrete is constrained, the fixation by the concrete is strong, so that is required for the column beam joint. Thus, the same shear reinforcement effect as that in the case where the existing closed type shear reinforcement is arranged is exhibited.

  A steel frame 4 of a beam 3 at a beam-to-column junction between a reinforced concrete or steel reinforced concrete column 1 and a steel or steel reinforced concrete or steel concrete beam 3 and having flanges 4b and 4b in the vertical section And As the shear reinforcement, a welded wire mesh 16 or a reinforcing steel lattice is used. The welded wire mesh 16 or the like surrounds the outer periphery of the column main reinforcing bar 5 and is cut off by the web 4a of the beam steel frame 4 when the column beam joint is viewed in plan view. It has a shape that fits within the range of the section and has a length approaching the web 4a of the beam steel frame 4, and at least one vertical bar 17 in the region where the upper and lower flanges 4b, 4b of the beam steel frame 4 restrain the concrete. Is provided. The above-described welded wire mesh 16 and the like are installed and implemented by means such as binding to the longitudinal main reinforcement 5 of the column 1.

1 to 3 show a first embodiment of a shear reinforcement structure for a beam-column joint according to the present invention.
The illustrated embodiment is a shear reinforcement structure of a beam-to-column joint between a steel reinforced concrete column 1 and a beam 3 which is either a steel structure, a steel reinforced concrete structure, or a steel concrete structure without a reinforcing bar. As shown in FIG. 3, the steel frame 4 of the beam 3 is formed of an H-shaped steel having flanges 4 b and 4 b at the top and bottom in a vertical section.
As the shear reinforcement, as shown in FIG. 1, a welded wire mesh 16 in which round steel bars are assembled in a lattice shape and the intersections are welded together is used. However, a reinforcing bar lattice formed by welding deformed reinforcing bars in a lattice shape, or a combination of vertical and horizontal reinforcing bars formed in a lattice shape (these are referred to as a welded wire mesh 16 or the like in the present invention) is also the same. Can be used to implement.
As shown in FIG. 2, the welded wire mesh 16 or the like surrounds the outer periphery of the column main reinforcing bar 5 and has four beam steel frames 4. It is divided into four sections cut off by the webs 4a and 4a and formed into an independent substantially L-shape. Moreover, the welded wire mesh 16 or the like is in a shape having a length close to the web 4a of the beam steel frame 4 that is accommodated within the range of each section and whose both end portions are opposed to each other. The upper and lower flanges 4b, 4b of each beam steel frame 4 are within the region for constraining the placed concrete (the region indicated by the dotted line in FIG. 3), and in the embodiment of FIGS. The muscle 17 is provided.

Naturally, the length of the vertical bars 17 includes, in particular, the dimension protruding in the vertical direction from the upper and lower horizontal bars 16a, so that the upper and lower flanges 4b and 4b of the beam steel frame 4 are efficient due to the effect of restraining the concrete. It is desired that the length be well supported. According to the Building Standards Act, the bar spacing in the beam-column joint is determined. When the horizontal bar 16a of the welded wire mesh 16 is aligned with the normal bar bar position, the required length of the vertical bar 17 is automatically determined. It cannot be shortened. Incidentally, in the case of the test body described below, the length of the longitudinal bars 17 is about 65% with respect to the inner height H (see FIG. 3) of the upper and lower flanges 4b, 4b of the beam steel frame 4.
In addition, when it is necessary for the design to increase the stress load of the welded wire mesh 16 or the like, the number of the horizontal bars 16a is increased or the diameter is increased. As a result, the stress acting on the longitudinal bars 17 also increases, so that further contrivance is required as described later (the invention described in claim 1 above).

  As shown in FIGS. 2 and 3, the above-described welded wire mesh 16 and the like are disposed so as to surround the outer periphery of the vertical main reinforcing bar 2 of the column 1, and are, for example, bound to the vertical main reinforcing bar 2 of the column 1 by a wire 18. Therefore, it is set to a level that can withstand concrete placement. Of course, the means for placing and arranging the welded wire mesh 16 and the like is not limited to the method of binding by the wire 18, and can be implemented using clips or the like. In addition, illustration of the number wire 18 was abbreviate | omitted in each following Example.

The results of a shear test that demonstrates the mechanical performance of the shear reinforcement structure of the beam-column joint configured as described above will be described below.
As test specimens, the configuration in which the upper and lower flanges of the beam steel frame 4 are deleted from the configuration of the above embodiment (hereinafter referred to as No. 1) and the configuration of the above embodiment itself (hereinafter referred to as No. 2). Two types of were prepared and tested.
FIG. 4 shows a load-deformation relationship in which a No. 1 specimen was subjected to a shear test. In this case, it is recognized that the destruction of the beam-column joint progresses and the proof stress is greatly reduced, so that the required proof strength cannot be secured and maintained.
FIG. 5 shows a load-deformation relationship in which a shear test of a No. 2 specimen (the above example) was conducted. In this case, although the end of the beam is crushed, R = 50 × 10 ⁻³ rad. The columnar shear force at the time was 94% of the peak, and it was confirmed that there was almost no decrease in yield strength.
As shown in FIG. 6 and the hysteresis curve envelope of FIGS. 4 and 5, the maximum proof stress of the No. 2 test body, which is the product of the present invention, is larger than that of the No. 1 test body. It is clearly recognized that the decrease in the yield strength after the demonstration of the yield strength is small. After all, the difference in performance is that, in the case of No. 2 specimen, the vertical bars 17 of the welded wire mesh 16 are subjected to strong support (restraint) action by the concrete constrained by the upper and lower flanges 4a, 4a of the beam steel frame 4. It is considered that the decrease in yield strength is small.

FIG. 7 shows an example of a device required when the stress burden of the welded wire mesh 16 or the like described in the latter part of the paragraph number [0019] is necessary. The top end portions where the upper and lower flanges 4b, 4b of the beam steel frame 4 are accommodated in the region where the concrete is constrained are bent inward in the same direction as the web 4a of the beam steel frame 4, and two bent portions 19 in the illustrated example are provided. The example which provided the vertical stripe 17 of this is shown.
Of course, the direction of bending the tip of the welded wire mesh 16 and the like can be similarly performed by bending outward in the same direction as the web 4a as shown by the dotted line in FIG. Invention described in the above).

  In the embodiment shown in FIG. 8, as an example of auxiliary means for further strengthening the action of the upper and lower flanges 4b, 4b restraining the concrete in the beam steel frame 4, the required number of studs 20 are installed, and the welded wire mesh 16 or the like is installed. The vertical reinforcement 17 provided in the part in which the upper and lower flanges 4b and 4b of the beam steel frame 4 are accommodated in the area | region which restrains concrete shows the structure which improved the bearing effect which restrains by concrete (Claim 3). Invention). However, the auxiliary means for constraining the concrete is not limited to the stud, and can be similarly implemented using a wire mesh or a shape steel.

  The embodiment shown in FIG. 9 concentrates a plurality of vertical bars 17 on the inside and outside of the front end portion of the welded wire mesh 16 and the like in which the upper and lower flanges 4b and 4b of the beam steel frame 4 are confined in the region where the concrete is restrained. The example of the structure provided in is shown (invention described in claim 4). It is also possible to change the thickness of the vertical stripes 17 to be larger or smaller.

FIG. 10 shows an embodiment relating to the column-column joint of the side column. This is basically the same configuration as in the embodiment of FIG. 2, but the horizontal section is a T-shaped column beam joint, and the T-shaped jaw (inner corner) has a symmetrical arrangement. A feature is that the L-shaped welded wire mesh 16 or the like is arranged in plan view, and a U-shaped welded wire mesh 16a or the like is arranged outside the T type.
FIG. 11 shows an embodiment relating to a column beam joint of a corner column. This is basically the same structure as the embodiment of FIG. 2, but the horizontal section is an L-shaped column beam joint, and the inner jaw (inner corner) is L-shaped in plan view. It is characterized in that the shape of the welded wire mesh 16 or the like is arranged and the outer corner is arranged with a welded wire mesh 16b or the like having a lip attached to both ends of a large L shape. However, it is expected that construction work is difficult due to a large resistance due to the rigidity of the reinforcing bars in the reinforcing work for expanding and inserting the welding wire mesh 16b having the shape shown in the outer corner. Therefore, in order to use the portion supported in the range K in FIG. 11 as a lap joint, the welding wire mesh 16a having a U-shape in plan view illustrated in FIG. 10 and the welding wire mesh 16 having an L-shape in plan view are combined. It is also possible to implement with a configuration in which bar arrangement is performed.

It is the perspective view which showed the column beam junction part of 1st Example of this invention. It is a horizontal sectional view of the above-mentioned column beam junction part. It is a vertical sectional view of the above-mentioned column beam junction. FIG. 3 is a load-deformation diagram of a No. 1 test body (non-example) demonstrating the effect of the first embodiment of the present invention. It is a load-deformation diagram of No. 2 test body (implemented product) demonstrating the effect of the first embodiment of the present invention. It is an envelope diagram of the two load-deformation diagrams. It is the horizontal sectional view which showed the column beam junction part of 2nd Example of this invention. It is the horizontal sectional view which showed the column beam junction part of the Example from which this invention differs. It is the horizontal sectional view which showed the column beam junction part of 3rd Example of this invention. It is the horizontal sectional view which showed the column beam junction part of the Example from which this invention differs. It is the horizontal sectional view which showed the column beam junction part of the Example from which this invention differs further. It is the horizontal sectional view which showed the conventional column beam junction part.

Explanation of symbols

1 Column 2 Column Steel 3 Beam 4 Beam Steel 16 Welded Wire Mesh 5 Column Main Reinforcement 4a Beam Steel Web 4b Beam Steel Flange 17 Vertical Reinforcement 20 Stud

Claims (5)

In a method for shear reinforcement of a column beam joint between a reinforced concrete structure or a steel reinforced concrete column and a steel structure or a steel reinforced concrete structure or a steel concrete structure beam,
The steel frame of the beam shall have upper and lower flanges in the vertical section,
A welded wire mesh or a reinforcing steel lattice is used as the shear reinforcement, and the welded wire mesh, etc., when viewed in plan view, surrounds the outer periphery of the column main bar and fits within the area of the section blocked by the beam steel web. A shape having a length approaching the web of the beam steel, and providing at least one vertical bar in a region where the upper and lower flanges of the beam steel restrain the concrete;
A method for shear reinforcement of a beam-column joint, wherein the welded wire mesh is installed by means such as binding to a longitudinal main bar of a column.   Of the welded wire mesh or reinforcing bar lattice, bend the part where the upper and lower flanges of the beam steel frame are within the area where the concrete is constrained, bend in the same direction as the web of the beam steel frame, and provide at least one vertical bar in the bent part The method for shear reinforcement of a beam-column joint according to claim 1.   The method for shear reinforcement of a beam-column joint according to claim 1 or 2, wherein a restraint assisting means such as a stud for restraining concrete is provided on the beam steel web.   A plurality of vertical bars are intensively provided inside and outside the portion of the welded wire mesh or the reinforcing bar lattice, etc., in which the upper and lower flanges of the beam steel frame are contained in the region where the concrete is constrained. The shear reinforcement method of the column beam joint part described in any one. In the shear reinforcement structure of the column beam joint between the reinforced concrete structure or steel reinforced concrete column and the steel structure or steel reinforced concrete structure or steel concrete structure beam,
The steel frame of the beam has a structure with flanges at the top and bottom in the vertical section,
A welded wire mesh or a reinforcing steel lattice is used as a shear reinforcement, and the welded wire mesh surrounds the outer periphery of the column main bar in a plan view of the column beam joint, and is within the range of the section blocked by the beam steel web. And having a length that approaches the web of the beam steel frame, and at least one vertical bar is provided in a region where the upper and lower flanges of the beam steel frame constrain the concrete,
The above-mentioned welded wire mesh is installed by means such as binding to the longitudinal main bars of the column, etc.

Images