JP4943141B2 - Joint structure of reinforced concrete columns and steel beams - Google Patents

Description

  The present invention relates to a column beam joint structure of a building having a composite structure in which a column is reinforced concrete and a beam is steel.

  In order to form a stable yield mechanism in the event of an earthquake in a building frame composed of columns and beams, it is generally necessary to generate a yield hinge at the beam end, except for the first-level column base and the top-level column head. .

  However, in an architectural framework in which the columns are reinforced concrete and the beams are steel, the beam width of the steel beam 2 is relatively narrow compared to the column width of the reinforced concrete column 1, as shown in FIGS. In the event of an earthquake, there is a possibility that concrete compressive failure (bearing failure) may occur due to excessive compressive force acting on the column concrete in the upper and lower portions of the beam flange 2a due to the lever action of the steel beam 2.

  Furthermore, the yield region of the beam may extend to the inside of the column beam joint when the yield hinge is formed at the end of the beam and due to repeated repeated loads due to the seismic force after the hinge is formed.

  If the bearing failure or the extension of the yield region of the beam into the column beam joint occurs, the resistance to the seismic force of the building is significantly reduced, which is not preferable.

  Many technologies have been developed and announced to reinforce the joints between reinforced concrete columns and steel beams in order to prevent destruction of column concrete above and below the beam flange and to prevent shear failure of column beam joints. One example is a method of providing a reinforcing material, such as a reinforcing material embedded in concrete or a reinforcing material covering the outer surface of the concrete.

  There is also a technique for adding a reinforcing material to a steel beam. For example, ribs are provided in the column concrete of the steel beam as shown in FIG. A steel longitudinal rib 22 is attached to the upper and lower surfaces of the steel beam 2 so as to protrude from one outer surface of the column to the other outer surface of the steel beam 2 where the steel beam 2 is embedded in the reinforced concrete column. The reinforcing plate 21 is attached to the beam 2 and the rib 22 in the surface direction, and this is embedded in the column concrete.

Further, in the following patent document, as shown in FIG. 10, ribs 4 are formed on the upper and lower surfaces of the flange of the H-shaped steel beam 2 on the surface of the reinforced concrete column where the reinforced concrete column 1 and the steel beam 2 intersect. The provided L-shaped reinforcing plate 3 was attached.
JP-A-8-27894 (bonded structure of reinforced concrete columns and steel beams)

  The thing of the said FIG. 9 shows the state before concrete placement of a reinforced concrete pillar, and the main reinforcement 23 and the hoop reinforcement 24 are exposed. This technique reinforces the connection between the steel beam and the column, but has little effect on the concrete peeling of the column.

  10 is mainly intended to prevent the steel beam 2 from coming out, but the L-shaped reinforcing plate 3 provided with the ribs 4 is installed on the surface portion of the reinforced concrete column. Therefore, it is not constrained inside the column concrete, and since it protrudes from the surface of the reinforced concrete column 1, there is a possibility that the construction of the column beam joint portion may be hindered.

  Furthermore, although the thing of this patent document 1 also strengthens the coupling | bonding of a steel beam and a column similarly to the thing of the said FIG. 9, there are few effects with respect to peeling of the concrete of a pillar.

  FIG. 11 shows an improvement of the above-mentioned Patent Document 1, in which a longitudinal rib-shaped reinforcing steel plate 5 that is equal to or greater than the beam width and is arranged above and below the beam flange 2a is positioned outside the surface of the reinforced concrete column 1, and A reinforcing steel plate 6 is arranged on the entire circumference of the column, and a reinforcing steel plate 7 having the same height as the beam is arranged between the rib 4 for bending reinforcement of the reinforcing steel plate 5 and the upper and lower flanges 2a of the steel beam 2.

  Similar to Patent Document 1, the reinforcing steel plate 5 and the reinforcing steel plate 6 have the same upper and lower surface positions and are joined to the surface position of the reinforced concrete column 1 to prevent collapse and peeling of the column concrete. .

  However, the joint structure shown in FIG. 11 incorporates three types of reinforcing steel plates, namely reinforcing steel plates 5 to 7, resulting in a complicated structure, which increases the processing cost of the steel frame.

  Moreover, since the said reinforcing steel plate 5 protrudes from the surface of the reinforced concrete pillar 1 like the said patent document 1, there exists a possibility that it may become the hindrance of the construction of a column beam junction part, and a housing | casing is not clear and is not preferable.

  The object of the present invention is to eliminate the inconveniences of the conventional examples described above, and, while having a simple structure, by effectively constraining the column concrete above and below the flange, the bearing strength of the concrete can be increased and the fit is reduced. It is also desirable to provide a reinforced concrete column and steel beam joint structure that can prevent the concrete from peeling off.

In order to achieve the above-mentioned object, the present invention according to claim 1 is a frame comprising a reinforced concrete structure for a column and a steel structure for a beam, and the steel beam is a reinforced concrete column and steel beam connection that penetrates the column beam connection. In the structure, vertical ribs are provided on the upper and lower portions of the upper and lower flanges of the steel beam so as to be parallel to each other along the flange edge and facing each other, and the vertical ribs intersect the beam steel frame in the column cross section. The part is provided so as to intersect at right angles, and the gist is to constrain the column concrete from the three directions of the vertical rib and the lateral reinforcement of the column part.

  According to the first aspect of the present invention, the tensile strength of the steel beam flange inside the column beam joint is made larger than the tensile strength of the flange of the beam portion by arranging vertical ribs on the upper and lower portions of the steel beam upper and lower flanges. Therefore, against the bearing pressure failure of the column concrete above and below the beam, the fracture can be prevented by restraining the vertical ribs provided above and below the beam flange and the lateral reinforcement of the column part from three directions.

  In addition, since the vertical ribs are provided along the flange edge and so as to be parallel to each other, the front and rear are opened and do not become a blocking obstacle wall. Absent.

  Furthermore, in the case of a column beam joint in which the steel beam penetrates the column beam joint, when concrete is placed in the column beam joint, it is easy to cause air accumulation at the bottom of the steel flange, so it is necessary to provide an air vent hole. However, the vertical ribs provided on the upper and lower portions of the flange also serve to compensate for the cross-sectional defect of the flange due to the air vent hole.

  In addition to this, the lateral reinforcing bars are provided with a larger amount of lateral reinforcing bars than the column portion, which is effective in preventing collapse and peeling of the core concrete of the column.

Furthermore, the upper and lower vertical ribs of the upper and lower flanges of the steel beam are provided so as to intersect at right angles at the portion where the beam steel frame intersects within the column cross section, so that the steel beam 2 is the joint of the reinforced concrete column 1. Even when intersecting, the vertical ribs can be provided in a compact manner without interfering with each other. In addition, the vertical ribs intersect at right angles, which is effective for preventing the core concrete of the column from being crushed and peeled off.

  The gist of the present invention described in claim 2 is that a reinforcing steel plate having a width equal to or greater than the beam width is disposed on the column surface of the beam penetration portion.

  According to the second aspect of the present invention, the presence of the reinforcing steel plate is effective in constraining the concrete of the column beam joint portion, and can also serve as a mold during construction. Processing and mounting can be facilitated.

The gist of the present invention described in claim 3 is that the column structure is precast reinforced concrete.

  In the case of placing concrete in a column beam joint at a construction site, a process such as preparing a form for the column beam joint separately and placing it separately from the concrete casting of the column was necessary. According to the fourth aspect of the present invention, a high-quality member can be provided and the construction period can be shortened by using a precast member produced at a factory or construction site including a column beam joint.

  In addition, in the case of a building that requires a high floor height and a long column length, the concrete side pressure acting on the formwork becomes large when the concrete is placed on the pillar, so the cost for curing the formwork is high. For this reason, it may be more rational to use a precast structure for the column.

The gist of the present invention described in claim 4 is that the column structure is a precast reinforced concrete structure, and an unbonded PC steel material is disposed inside the column.

According to this invention of Claim 4 , in addition to the said effect | action, when making a column into the precast member containing a column beam joint, unbonded PC steel material is arranged inside a column, and PC steel material at the time of column construction By applying tension to the column, it is possible to give the column bending rigidity required during construction.

The gist of the present invention described in claim 5 is that the column structure is a precast prestressed concrete structure.

According to the fifth aspect of the present invention, it is possible to reduce the construction cost by shortening the construction period and the like by reducing the placing of the concrete at the conventional construction site as much as possible by making the column a prestressed concrete structure. can do. Furthermore, since the required prestress force is applied, the bending cracking strength of the column increases, and even after the occurrence of the bending cracking, it can be expected that the bending crack will close due to the prestressing force after the earthquake, and the residual crack width is Durability is improved because it is extremely small compared to ordinary reinforced concrete columns.

The gist of the present invention described in claim 6 is that the structure of the pillar is a precast prestressed concrete structure, and a required number of precast members are connected by a prestressing force by reducing the weight of one member.

According to this invention of Claim 6, when the length of the said pillar is long and makes a pillar a precast member, since the weight of one precast member will become very heavy, if a precast member is divided and constructed, Construction cost can be reduced by reducing the required capacity of the lifting machine.

  As described above, the joint structure of the reinforced concrete column and steel beam according to the present invention is a simple structure, but can effectively increase the bearing strength of the concrete by effectively restraining the column concrete above and below the flange. In addition, it fits well and can also prevent the concrete from peeling off.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a joint structure of a reinforced concrete column and a steel beam according to the present invention, FIG. 2 is a plan view of the same as above, and adopts a framework composed of a reinforced concrete column and a beam steel frame, The steel beam 2 is a case where it penetrates the column beam joint. The beam width of the steel beam 2 is relatively narrow with respect to the column width of the reinforced concrete column 1.

  In the present invention, the tensile strength of the flange 2a of the steel beam 2 inside the column beam joint is made larger than the tensile strength of the flange of the beam portion. The longitudinal ribs 9 are provided so as to be parallel to each other along the edge of the flange 2a and facing each other.

  The height of the vertical rib 9 is about 75 to 120/1000 of the beam formation.

  When the steel beam 2 is orthogonal, the vertical ribs 9 are provided at right angles to each other at the corner of the steel beam crossing portion. The right-angled corner may be opened without abutting.

  In the figure, reference numeral 13 denotes an air vent hole provided in the flange 2a, which is a countermeasure for easily causing an air pocket at the lower part of the steel flange when placing concrete in the column beam joint. In order to prevent this, a minimum number (two in the drawing) was provided between the parallel vertical ribs 9.

  In the figure, reference numeral 10 denotes a column main reinforcing bar. A horizontal reinforcing bar 11 which is a hoop line wound around the column main reinforcing bar 10 is disposed on the side of the vertical rib 9, and column concrete is formed between the vertical rib 9 and the column portion. The lateral reinforcing bars 11 are restrained from three directions.

  This lateral reinforcing bar 11 is an extension of the lateral reinforcing bar 8 in the other part of the column.

  Further, a reinforcing steel plate 12 having a width equal to or greater than the beam width is disposed on the column surface of the beam penetration portion of the steel beam 2 with respect to the reinforced concrete column 1.

  The above is the joint structure of a reinforced concrete column and a steel beam according to the present invention. Next, a method for constructing a frame composed of a column having such a joint structure made of reinforced concrete and a beam made of steel will be described.

  FIG. 5 shows various cases. (A) shows a case where the reinforced concrete column 1 is constructed on site, that is, cast in place, and (b) shows a case where a precast reinforced concrete structure is used. When the column beam joint portion is also precast, (c) is a case of a column beam joint integrated type.

  Thus, by using a precast member produced at a factory or construction site including a column beam joint, a high-quality member can be provided and the construction period can be shortened.

  Furthermore, in the case of (c), not only is the pillar structure made of precast reinforced concrete, but illustration is omitted, but a PC steel material that is unbonded may be disposed inside the pillar. If it does in this way, how to build a pillar can be made easy by giving the bending rigidity required for construction at the time of pillar construction, and becoming independent.

  Moreover, it is good also considering the structure of the reinforced concrete pillar 1 as a precast prestressed concrete structure.

  (D) is a case where the weight of one member is reduced when the structure of the reinforced concrete column 1 is a precast prestressed concrete structure. The necessary number of precast members were connected by a prestressing force to facilitate the building of the pillars.

It is a perspective view which shows one Embodiment of the joint structure of a reinforced concrete pillar and steel beam of this invention. It is a top view which shows one Embodiment of the joint structure of a reinforced concrete pillar and steel beam of this invention. It is a side view which shows one Embodiment of the joint structure of a reinforced concrete pillar and steel beam of this invention. It is a side view of the principal part of the steel beam used in the joint structure of a reinforced concrete pillar and steel beam of the present invention. It is explanatory drawing which shows the construction method in the joint structure of the reinforced concrete pillar and steel beam of this invention. It is explanatory drawing which shows the restraint of the concrete of the joint structure of the reinforced concrete pillar and steel beam of this invention. It is explanatory drawing which shows the lever effect | action of a beam steel frame. It is explanatory drawing which shows the bearing failure of a beam steel flange upper and lower column concrete. It is a perspective view which shows the 1st example of a prior art example. It is a perspective view which shows the 2nd example of a prior art example. It is a perspective view which shows the 3rd example of a prior art example.

DESCRIPTION OF SYMBOLS 1 ... Reinforced concrete pillar 2 ... Steel beam 2a ... Flange 3 ... Reinforcement plate 4 ... Rib 5 ... Reinforced steel plate 6 ... Reinforced steel plate 7 ... Reinforced steel plate 8 ... Lateral reinforcement 9 ... Vertical rib 10 ... Column main reinforcement 11 ... Lateral reinforcement 12 ... Reinforcing steel plate 13 ... Air vent hole 21 ... Reinforcing plate 22 ... Rib 23 ... Main bar 24 ... Hoop bar

Claims (6)

It is a frame composed of reinforced concrete columns and steel frames. Steel beams are reinforced concrete columns and steel beam joints that penetrate the column beam joints. The ribs are provided along the edges and parallel to each other, and the vertical ribs are provided so as to intersect at a right angle at the crossing section of the beam steel in the column cross section. The joint structure of reinforced concrete columns and steel beams, which is restrained from the three directions of the ribs and lateral reinforcement of the column part.   The joint structure of a reinforced concrete column and a steel beam according to claim 1, wherein a reinforcing steel plate having a width equal to or greater than the beam width is disposed on the column surface of the beam penetration portion. The joint structure of a reinforced concrete column and a steel beam according to claim 1 or 2, wherein the column structure is a precast reinforced concrete structure. The joint structure of a reinforced concrete column and a steel beam according to any one of claims 1 to 3 , wherein the column structure is a precast reinforced concrete structure and an unbonded PC steel material is disposed inside the column. The joint structure of a reinforced concrete column and a steel beam according to any one of claims 1 to 4 , wherein the column structure is a precast prestressed concrete structure. The joint structure of a reinforced concrete column and a steel beam according to claim 5, wherein the column structure is a precast prestressed concrete structure, and a required number of precast members are connected by a prestressing force by reducing the weight of one member.

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