JP2009161974A - Reinforced concrete beam construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforced concrete beam construction method which is applicable to construction of a both end fixed frame in which columns and a reinforced concrete beam are rigidly jointed to each other, wherein the method brings about reduction of end moment occurring at each end of the reinforced concrete beam. <P>SOLUTION: In carrying out the reinforced concrete beam construction method, at least the ends of the reinforced concrete beam 6 are formed of precast concrete products, and reinforcements 2 protruding from the column 15 in a beam longitudinal direction are inserted into sleeves 7 or 15 embedded in the ends. In the process of construction work, each beam end is pinconnected to the column, and the following construction work is continued in this state. Then after completion of predetermined steps, grout 13 is poured in the sleeves, and thus the beam ends are rigidly jointed to the columns. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for constructing a reinforced concrete beam, and more particularly, a reinforced concrete beam capable of suppressing stress (end moment) generated at an end of a reinforced concrete beam in a fixed structure with both ends fixed by rigidly joining a column and a reinforced concrete beam. It relates to the construction method.

  In general, in a high-rise building, as shown in FIG. 1, one pillar A is often supported one by one with a foundation pile B having a high yield strength. Due to the so-called group pile effect in which the stress lines inside overlap, the settlement of the foundation pile B tends to be larger on the center side of the building than on the outer periphery of the building. As shown in FIG. 1, forced deformation occurs in the girder C due to the difference in the amount of settlement of the foundation piles (uneven settlement of the building). Therefore, the end moment of the girder C is balanced at the outer end of the girder C ( Arrow a) occurs. Accordingly, the large beam C is required to have a large beam strength, and there are cases where the cross-section design becomes difficult with respect to the generated stress. Incidentally, on the center side of the building, a plurality of pillars A are arranged in a lattice pattern with a predetermined span, and the foundation pile B is also arranged correspondingly, but FIG. Since it is a schematic diagram explaining lifting, for convenience of explanation, only one pillar A and one foundation pile B on the center side of the building are shown.

  In addition, in a frame fixed at both ends, such as a column beam in a reinforced concrete building, as shown in Fig. 2, the stress (end moment) resulting from the total weight of the weight, finishing load and loading load is applied to the span end. As a result, the stress at the end of the span increases in proportion to the square of the span as the span increases. Therefore, when a long span large beam is constructed, the stress (arrow b) generated at the end of the span becomes extremely large. To cope with this stress, the beam formation is increased and the amount of rebar at the end of the beam is increased. Measures will be taken.

  In addition, as the weight of the large beam increases and the stress at the end of the large beam (arrow b) increases, the stress (arrow c) that occurs in the column that supports the large beam also inevitably increases. It is necessary to take measures such as increasing the number of bars.

  Although it is a technology that targets steel-framed large beams, in order to reduce the stress at the end of the steel beam, the end of the beam is connected to the column by bolting, and in this state, the deck plate Patent Document 1 proposes a method of joining a column and a steel beam in which the steps of laying, slab reinforcement, concrete placement, etc. are advanced, and after the slab is completed, the beam end is welded to the column to make it rigidly connected. ing.

  In this prior art, the web at the end of the steel beam is bolted to a gusset plate provided on the column to make a pin connection, and then the upper and lower flanges at the end of the beam are butt welded to the column to make a rigid connection. It has the advantage that the end stress of the steel beam can be reduced by simply changing the general construction procedure of constructing the slab to the order of bolting, slab construction and butt welding.

  However, reinforced concrete beams originally do not have steps such as bolting or welding of steel beams, so the above-described conventional technique cannot be applied to the joining of reinforced concrete beams. In addition, each time a slab is built one layer at a time, the upper and lower flanges of the beam end are butt welded to the column to make a rigid joint, so that a separate measure is taken against the forced deformation of the steel beam due to the uneven settlement of the building. is required.

JP-A-8-218640

  The present invention has been made in view of the above-mentioned problems, and its object is to provide an end moment generated at the end of a reinforced concrete beam in a frame fixed at both ends with a rigid connection between a column and a reinforced concrete beam. To provide a method for constructing a reinforced concrete beam that can suppress (for example, lifting of the end moment of a reinforced concrete beam due to uneven settlement of the building, lifting of the end moment of a long span reinforced concrete beam, etc.) It is in.

  The technical means taken by the present invention in order to achieve the above object are as follows. In other words, the method for constructing a reinforced concrete beam according to the first aspect of the present invention is the reinforcing bar in which the end portion of the reinforced concrete beam whose end portion is a precast concrete product is protruded in the beam longitudinal direction from the column side to the sleeve embedded in the end portion. In the middle of the construction, the beam end is pin-joined to the column in the middle of the construction, and in this state, the subsequent construction work is advanced, and after completing the predetermined process, the grout is injected into the sleeve, The beam end is rigidly connected to the column.

  Invention of Claim 2 is a construction method of the reinforced concrete beam of Claim 1, Comprising: Only the edge part is made into a precast concrete product among reinforced concrete beams, and it is a column side in the sleeve embedded in the said precast concrete product. In the middle of the construction, insert a reinforcing bar that protrudes in the longitudinal direction of the beam and connect the leading end of the reinforcing bar that penetrates the sleeve and the beam main reinforcing bar of the beam part that is constructed by spotting the concrete with a joint. In this state, the beam ends are pin-joined to the columns, and after that, the building work is proceeded, and after the predetermined process is completed, the grouts are injected into the sleeves to make the beam ends rigid to the columns. It is characterized by joining.

  Invention of Claim 3 is the construction method of the reinforced concrete beam of Claim 1, Comprising: The whole reinforced concrete beam is made into a precast concrete product, and it is a column side in the sleeve embedded at the edge part of the said precast concrete product. By inserting a reinforcing bar protruding in the longitudinal direction of the beam, the end of the beam is pin-bonded to the column during the construction process. It is characterized in that the end of the beam is rigidly connected to the column by injecting grout inside.

  The inventions according to claims 1 to 3 are such that both ends of the beam are pin-bonded in the middle of construction, and both ends of the beam are rigidly joined after completion of a predetermined process, and one end of the beam in the middle of construction. Only the pin connection (the other end is a rigid connection), and after the predetermined process is completed, the one end of the beam is a rigid connection.

  Invention of Claim 4 is the construction method of the reinforced concrete beam in any one of Claims 1-3, Comprising: The reinforcing bar made to project in the beam longitudinal direction from the column side, and the beam main reinforcement embed | buried in the precast concrete product And a joint sleeve that is slidable between a non-connected state in which only one of the reinforcing bar and the beam main bar is fitted and a connected state in which approximately half of the reinforcing bar and the beam main bar are fitted to each other. Further, it is characterized in that it is connected by a slide joint provided with a sheath tube forming the storage space.

Invention of Claim 5 is the construction method of the reinforced concrete beam in any one of Claims 1-4, Comprising: The outer edge part of a reinforced concrete beam is made into a pin connection with respect to a column in the middle of construction, The beam end is rigidly connected to the column by injecting grout into the sleeve.

  Invention of Claim 6 is the construction method of the reinforced concrete beam in any one of Claims 1-4, Comprising: In the middle of construction, both ends of the reinforced concrete beam are made into a pin joint, After placing the slab concrete, the beam end is rigidly connected to the column by injecting grout into the sleeve.

  According to the first to third aspects of the present invention, the end moment generated at the end of the reinforced concrete beam can be suppressed in the frame with both ends fixed by rigidly connecting the column and the reinforced concrete beam, and a rational large beam cross-section design is possible. There is an effect.

  In other words, when building a reinforced concrete building, such as a super high-rise building, where uneven settlement of the building is expected due to the group pile effect during construction, the longitudinal direction of the beam from the column side to the sleeve embedded at the outer end of the reinforced concrete beam In the middle of construction, the end of the beam is pin-joined to the column, and the subsequent construction work is proceeded in this state. For example, as in the fifth aspect of the present invention, after the upper ridge, a grout is injected into the sleeve to establish a fixed structure in which both ends of the beam are rigidly joined.

  Therefore, even if the reinforced concrete beam is forcedly deformed due to uneven settlement of the building during construction, the end of the beam is pin-jointed, so the stress at the outer end due to the forced deformation of the reinforced concrete beam (end moment) ) Is zero in principle. And after forced deformation of the reinforced concrete beam occurs, grout is injected into the sleeve to establish a fixed structure with both ends fixed, and the end moment generated at the end of the reinforced concrete beam is It can be reduced as much as the end moment caused by forced deformation of the reinforced concrete beam is prevented.

  When constructing long-span reinforced concrete beams, insert reinforcing bars projecting in the longitudinal direction of the beam from the column side into sleeves embedded at both ends of the reinforced concrete beam. In this state, the end of the beam is made into a pin joint, and the subsequent construction work is proceeded. After the predetermined process is completed, specifically, the slab concrete on the beam is formed as in the invention according to claim 6. After the placement, grout is injected into the sleeve to form a fixed frame with both ends fixedly joined.

  Accordingly, during construction, the end pin is structurally established with respect to its own weight, and the end portion of the reinforced concrete beam is pin-connected, so that the end moment is zero in principle. And after placing the slab concrete, grout is injected into the sleeve to rigidly join the beam ends, so the end moment generated at the end of the reinforced concrete beam after the slab construction is caused by the finishing load and the loading load. However, the end moment generated at the end of the reinforced concrete beam can be reduced even though it is a long span reinforced concrete beam.

  In the middle of construction, the end of the reinforced concrete beam is pin-bonded to increase the stress at the center of the span. However, near the center of the span, the joint effect of the slab can be expected. During construction, even if the stress is increased at the center of the span with both ends supported as pins, the cross-section is unlikely to be increased. Moreover, although it is a general method with a long span beam, prestress may be introduced only in the center portion of the span.

In particular, according to the invention described in claim 2, in addition to the above-described effects, the beam ends are pin-bonded during the construction in spite of the fact that they are reinforced concrete beams in which the majority in the longitudinal direction is constructed by cast-in-place concrete. Thus, the end moment generated at the end of the reinforced concrete beam can be suppressed.

  According to the invention described in claim 4, even when the entire reinforced concrete beam is a precast concrete product, the precast concrete product is hung from above between the columns and protrudes in the beam longitudinal direction from the column side. The workability is good because the rebars and the beam main bars embedded in the precast concrete product can be mechanically connected to each other by a joint sleeve to form a pin joint.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 3-8 shows an example of the construction method of the reinforced concrete beam which concerns on this invention. This construction method is used in a reinforced concrete building such as the high-rise building described with reference to Fig. 1 in the middle of the construction. It is used when reinforced concrete beams are installed.

  In FIG. 3, reference numeral 1 denotes a reinforced concrete column, and a plurality of reinforcing bars 2 serving as end portions of the beam main bars protrude from the side surface in the beam longitudinal direction. Further, a temporary beam receiving metal fitting 3 is attached to the side surface of the column 1, and a cotter engaging recess 4 is formed above the beam receiving metal fitting 3. 3 and 4, 5 is a precast concrete product constituting the end of the reinforced concrete beam 6 shown in FIG. 8, and a through-hole forming sleeve (hollow tube) 7 into which the reinforcing bar 2 is inserted is embedded. A cotter engagement recess 8 facing the cotter engagement recess 4 is formed on the end surface. Then, as shown in FIG. 8B, the grout 13 injected at an appropriate time is cured so as to fill the concave portions 4 and 8 so as to function as a cotter. . Further, in the precast concrete product 5, a pipe 9 used for grout injection and confirmation of the injection state is embedded in a state communicating with the sleeve 7.

  The construction method of the reinforced concrete beam 6 will be described. First, as shown in FIGS. 5 and 6, the rebar 2 protruded from the side surface of the column 1 is inserted into a sleeve 7 embedded in the precast concrete product 5, and the precast concrete product is inserted. The cotter 8 of 5 is engaged with the cotter engaging recess 4 on the side of the column, and the precast concrete product 5 is supported by the beam bracket 3.

  After that, as shown in FIG. 7, the beam form 9 is assembled and the beam is laid, and the beam main reinforcement 11 of the beam portion constructed by the on-site side of the rebar 2 penetrating the sleeve 7 and the concrete 10 in place. Are connected by a joint 12 such as a lap joint or a mechanical joint, and a concrete 10 is placed. As shown in FIG. 8A, a reinforced concrete beam 6 having a beam end pin-connected to a column 1 is provided. To construct.

  In this state, the subsequent building work is advanced, and after the predetermined process is completed, specifically, for example, by injecting the grout 13 into the sleeve 7 as shown in FIG. Then, a reinforced concrete beam 6 having a beam end rigidly connected to the column 1 is constructed. Reference numeral 14 denotes a slab.

  Although not shown, the other end side (inner end side) of the reinforced concrete beam 6 is symmetric with FIG. 8, but it is not necessary to make a pin joint in the middle of construction, in other words, make a rigid joint in the middle of construction. Also good. In this case, grout injection is performed before or after the concrete 10 is placed.

  The temporary beam support 3 may be removed when the beam form 9 is disassembled and removed. Further, instead of the temporary beam bracket 3, a support such as a pipe support may be used. The pillar 1 is made of precast concrete, but may be constructed by cast-in-place concrete.

  According to the above configuration, the end moment generated at the end of the reinforced concrete beam 6 can be suppressed in the frame with both ends fixed in which the column 1 and the reinforced concrete beam 6 are rigidly joined, and a rational large beam cross-section design is possible. That is, even if the reinforced concrete beam 6 is forcedly deformed due to the group subsidence due to the group pile effect during construction, the end of the beam is a pin joint, so the outer end caused by the forced deformation of the reinforced concrete beam 6 The stress (end moment) of the part becomes zero in principle.

  Then, after forced deformation of the reinforced concrete beam 6 occurs, a grout 13 is injected into the sleeve 7 to form a fixed structure with both ends fixed to be rigidly joined, so that an end generated at the end of the reinforced concrete beam 6 is formed. The part moment can be reduced as much as the end moment caused by the forced deformation of the reinforced concrete beam 6 is prevented.

  FIG. 9 shows another embodiment of the present invention, which is characterized in that the entire reinforced concrete beam 6 is a precast concrete product 5. That is, in this embodiment, as shown in FIG. 9 (A), the reinforcing bar 2 that protrudes in the beam longitudinal direction from the side surface of the column 1 to the joint sleeve 15 embedded in the end of the precast concrete product 5 is provided. By inserting, a reinforced concrete beam 6 having a beam end pin-connected to the column 1 during construction is constructed.

  In this state, the subsequent building work is advanced, and after the predetermined process is completed, specifically, after the upper building, as shown in FIG. 9B, the grout 13 is injected into the sleeve 15. Thus, the reinforced concrete beam 6 in which the beam end portion is rigidly connected to the column 1 is constructed. Although the pillar 1 is illustrated as being made of precast concrete, it is constructed in advance by a cast-in-place concrete up to a height at which the temporary beam support 3 can be attached (lower end of the beam), and the tip of the reinforcing bar 2 is inserted into the sleeve 15. In the state, you may make it hand over to the upper floor. Since other configurations and operations are the same as those of the previous embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

  FIG. 10 shows another embodiment of the present invention, which is characterized in that the hinge zone L is removed and the precast concrete product 5 is joined. Specifically, as shown in FIG. 10A, precast concrete beam members 5a and 5b having a length corresponding to the hinge zone L are protruded from the pillars 1 on both sides, and the precast is interposed between them. A concrete product 5 is arranged. Then, a reinforcing bar (which is also an example of a reinforcing bar protruding from the column side) 2 protruded from one precast concrete beam 5a is inserted into a joint sleeve 15 embedded in one end of the precast concrete product 5. At the same time, the main beam 11 projected from the other end of the precast concrete beam member 5 is inserted into a joint sleeve 15 embedded in the other precast concrete beam member 5b, so that the column 1 is formed during the construction. On the other hand, a reinforced concrete beam 6 having a beam end pin-joined is constructed.

  In this state, the subsequent building work is advanced, and after the predetermined process is completed, specifically, after the upper building, as shown in FIG. 10 (B), the grout 13 is injected into the sleeve 15. The reinforced concrete beam 6 is constructed in which the beam end is rigidly connected to the column 1. Reference numerals 16a and 16b in the figure denote column main reinforcement joint sleeves in which the column main reinforcement 17 penetrating the precast concrete beam members 5a and 5b is inserted and integrated by grout injection. Since other configurations and operations are the same as those in the embodiment of FIG. 9, the same reference numerals are given to the same structural members, and description thereof is omitted.

  11 to 13 show another embodiment of the present invention. In this embodiment, the rebar 2 projecting in the beam longitudinal direction from the column 1 side and the beam main bar 11 embedded in the precast concrete product 5 are fitted in only one of them, and approximately half in both. It is characterized in that it is connected by a slide joint 19 provided with a sleeve 15 for a joint that can be slid over the connected state, and sheath tubes 18a and 18b that form the storage space.

  Specifically, after projecting precast concrete beam members 5a and 5b having a length corresponding to the hinge zone L from the pillars 1 on both sides, respectively, as shown in FIG. In this way, the sleeve 15 is fitted only to the rebar 2 of the precast concrete beam 5a (or, conversely, the sleeve 15 is fitted only to the main beam 11 embedded in the precast concrete product 5). In a non-connected state), the precast concrete product 5 is suspended between the precast concrete beam members 5a and 5b. In this state, as shown in FIG. 12 (B), the sleeve 15 is pulled out to be in a connected state in which the rebar 2 and the beam main bar 11 are approximately half-fitted, as shown in FIG. 11 (A). In the middle of the construction, a reinforced concrete beam 6 is constructed with the beam end being pin-joined to the column 1. In many cases, the hinge zone L is approximately 1.0 to 1.5 times the beam formation.

  In this state, the subsequent construction work is advanced, and after the predetermined process is completed, specifically, for example, after the upper building, as shown in FIGS. 11B and 13, the grout 13 is injected into the sleeve 15. By doing this, the reinforced concrete beam 6 with the beam end rigidly joined to the column 1 is constructed.

  According to the above configuration, although the entire reinforced concrete beam 6 is the precast concrete product 5, the beam main bar does not protrude from the precast concrete product, so the precast concrete product 5 is suspended between the columns from above. The rebar 2 projecting from the column side in the beam longitudinal direction and the beam main bar 11 embedded in the precast concrete product 5 can be mechanically connected by a joint sleeve 15 to form a pin joint. good. Since other configurations and operations are the same as those in the embodiment of FIG. 10, the same components are denoted by the same reference numerals and description thereof is omitted.

  In many cases, the progress of the uneven settlement of the building due to the group pile effect becomes gradual when the building is built to a certain height, and the influence of the uneven settlement is reduced. Therefore, the grout injection may be performed after the upper building as in the above-described embodiment, but may be performed at a time when the height is set so that the influence of the uneven settlement does not cause a design problem even before the upper building. In addition, in the above-described embodiments, in the reinforced concrete building where the uneven settlement of the building due to the group pile effect is expected in the middle of construction such as the high-rise building described based on FIG. Although the case where a reinforced concrete beam is installed between the columns on the center side is targeted, the present invention can also be applied to the case where a long span reinforced concrete beam is constructed. In this case, in the middle of construction, both ends of the reinforced concrete beam are pin-bonded, and after placing the concrete of the slab supported by the reinforced concrete beam, grout is injected into the sleeve 7 or 15 to be rigidly bonded. Become.

It is a mimetic diagram explaining lifting of the end moment by forced deformation of a girder. It is a moment diagram in a frame fixed at both ends. It is a perspective view of the principal part which shows embodiment of this invention. It is a vertical side view of the principal part. It is explanatory drawing of the construction method of a reinforced concrete beam. It is explanatory drawing following FIG. It is explanatory drawing following FIG. It is explanatory drawing following FIG. It is explanatory drawing of the construction method of the reinforced concrete beam which shows other embodiment of this invention. It is explanatory drawing of the construction method of the reinforced concrete beam which shows other embodiment of this invention. It is explanatory drawing of the construction method of the reinforced concrete beam which shows other embodiment of this invention. It is a vertical side view of the principal part explaining a slide joint. It is a vertical side view of the principal part explaining a slide joint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Column 2 Reinforcement 3 Beam receiving bracket 4 Recessed cotter engagement 5 Precast concrete product 5a, 5b Precast concrete product 6 Reinforced concrete beam 7 Sleeve for through-hole formation 8 Recessed cotter engagement 9 Beam formwork 10 Concrete 11 Beam main reinforcement 12 Joint 13 Grout 14 Slab 15 Joint sleeve 16a, 16b Column main reinforcement sleeve 17 Column main reinforcement 18a, 18b Sheath tube 19 Slide joint

Claims (6)

  By inserting a reinforcing bar protruding in the longitudinal direction of the beam from the column side into a sleeve embedded in the end of the reinforced concrete beam whose end is a precast concrete product, the beam end with respect to the column during construction is inserted. The part is made into a pin joint, and after that, the building work is advanced in this state, and after a predetermined process is completed, a grout is injected into the sleeve to make the beam end rigidly joined to the column. To build reinforced concrete beams.   Only the end of the reinforced concrete beam is a precast concrete product, and a reinforcing rod that protrudes in the beam longitudinal direction from the column side is inserted into a sleeve embedded in the precast concrete product, and the reinforcing rod penetrates the sleeve of the precast concrete product. By connecting the tip side of the beam and the beam main reinforcement of the beam part built by spotting concrete, the beam end is pin-bonded to the column during the construction, and the subsequent construction work proceeds in this state, The method for constructing a reinforced concrete beam according to claim 1, wherein after the predetermined process is completed, the end of the beam is rigidly joined to the column by injecting grout into the sleeve.   The entire reinforced concrete beam is a precast concrete product. By inserting a reinforcing bar that protrudes in the longitudinal direction of the beam from the column side into a sleeve embedded in the end of the precast concrete product, the beam is against the column during construction. The end part is a pin joint, and in this state, the subsequent building work is proceeded. After a predetermined process is completed, the end of the beam is rigidly joined to the column by injecting grout into the sleeve. The construction method of the reinforced concrete beam of Claim 1.   A non-connected state in which the reinforcing bars projecting in the longitudinal direction of the beam from the column side and the main reinforcing bars embedded in the precast concrete product are arranged concentrically, and fitted to only one of the reinforcing bars and the main reinforcing bars. And a joint sleeve that is slidable over a connection state in which approximately half of them are connected to each other, and a sheath joint that forms a storage space of the joint sleeve. The construction method of the reinforced concrete beam in any one of.   The outer end of the reinforced concrete beam is pin-bonded to the column during construction, and the beam end is rigidly connected to the column by injecting grout into the sleeve after the upper building. The construction method of the reinforced concrete beam in any one of claim | item 1-4.   During construction, both ends of the reinforced concrete beam are pin-bonded to the column, and after placing the slab concrete on the beam, grout is injected into the sleeve, so that the beam end is rigidly bonded to the column. A construction method of a reinforced concrete beam according to any one of claims 1 to 4.

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