KR100436341B1 - Building member with cutting bar joint and building using the same - Google Patents

Abstract

The present invention relates to a construction member having a cutting rebar junction and a construction structure using the same, which can reduce the protruding rebar length of the bending member, and an object of the present invention is a construction member having a plurality of bending members, the construction member It is possible to achieve by the method and the construction member, characterized in that the reinforcing bar is joined to the cutting member is installed in the critical region of the reinforcing bar can reduce the protruding length of the bending member.

Description

Construction member and structure applying cutting rebar joining method {BUILDING MEMBER WITH CUTTING BAR JOINT AND BUILDING USING THE SAME}

The present invention relates to a construction member having a cutting reinforcing bar connection structure and a construction structure using the same, and more particularly, when there is a critical region under stress in the vicinity of the joint surface of the construction member by using the cutting reinforcing bars It relates to a construction member and a construction structure using the same away from the joint surface of the construction member.

In the reinforced concrete structure of the building, the reinforcing bar of the flexural member protrudes to a sufficient length so that the reinforcing bar of the flexible member is fixed to the supporting member, that is, the slab is fixed to the supporting beam or the supporting wall to maintain structural continuity and to ensure stability. It should be buried in the supporting member and fixed. Alternatively, in order to make continuous joints between members, reinforcing bars between members should have sufficient joint length. For this purpose, reinforcing bars should be protruded by joint length from member joints. However, when the protruding length is increased, considerable difficulties occur in the process of reinforcing bar reinforcement, fabrication, transportation, and assembly, and thus, a lot of cost and workforce are required.

The critical section refers to the position of the cross section where the magnitude of the bending moment due to the external force acting and the bending strength of the member are the same. In general, when a load acts on the bending member, the maximum bending moment is generated at the end and the center of the member, and according to the magnitude of the moment, the required reinforcing bar is placed in the member so that the member supports it. Therefore, the maximum critical region is usually located at the end and the center of the member. However, in order to continuously use the flexural member between the supporting points or the connection points between the members, the reinforcing bars should be protruded outward from the member support point or any connection point in consideration of the continuity of the rebar. At this time, if the critical region is located at the end of the member, the anchoring length of the reinforcing bar must be secured from this position, and if it is located in the member, the joint length between the members must be secured from any connection point in the member.

Problems of the prior art will be described with reference to the drawings. 1 is a cross-sectional view illustrating a problem of reinforcing bar reinforcement applied in the construction of a conventional building structure. FIG. 1 shows a beam 20 installed on one pillar 10 and a right side, and assumes that a force in the direction as shown is applied to the beam 20. The critical section on the beam 20 for the force in the direction shown is in the form of a parabola, shown by the dotted lines. In other words, the maximum bending moment occurs at the tip and the middle of the beam 20. However, in order to continuously use the flexural member beyond the support point, and to connect the joints generated at any point in the member when integrally manufacturing one member into a plurality of members, reinforcing bars at the joints of the divided members Protrude as long as the joint length of.

At this time, in consideration of the continuity of the reinforcing bars 31, the reinforcing bars should be disposed outside the member, and the minimum extension length of the reinforcing bars 31 extending from the critical area to the outside is called the settling length "Ld" from the critical area. The length of the reinforcing bar 31 extending from the outside of 20 is defined as the protruding length "Pd". As shown in FIG. 1, in the case of the reinforcing bar 32 provided in the critical area generated in the central area instead of the leading end area of the member, a sufficient fixing length "Ld" is secured from the critical area so that the protruding length of the reinforcing bar 32 is provided. It can be short enough so that there is no difficulty in construction.

FIG. 2 illustrates a problem in construction that occurs when two beams 20 having a protruding length "Pd" of the reinforcing bar 31 shown in FIG. 1 are constructed in close proximity to the column 10. Conventionally, since the total length of the reinforcing bar 31 extending from the beam 20 is provided as "Pd", the above-mentioned problems are brought about in transportation, manufacturing and field construction. In addition, as shown in FIG. 2, in the field construction, the workers bend the protruding reinforcing bars 31 protruding from the beams 20 before joining the beams 20 to each other, and then combine both beams 20. After joining, the work of bending the rebar to its original straight shape is brought to the site construction problem.

Accordingly, an object of the present invention is to move the critical section due to the bending stress to the end of the support member and to the inside of the bending member other than any joint in order to minimize the protruding length of the reinforcing bar protruding from the joint of the construction structure. In presenting the construction structure applying the method.

1 is a cross-sectional view for explaining the problem of reinforcement bar is applied when the conventional building structure construction.

Figure 2 is a cross-sectional view of the column and beam for explaining the construction problem of the conventional rebar having a protruding length.

3 is a cross-sectional view showing an ideal arrangement of the bending member in the construction member.

4 is a partial cross-sectional view of the building structure of one embodiment of the present invention subjected to cutting rebar bonding.

5 is a view for explaining an embodiment of cutting rebar bonding.

Figure 6 is an embodiment of the present invention applied to the piers and piers top plate.

7 is a graph showing the relationship between the moment (moment Mu / φ applying the load factor and the reduction factor) and the resistance moment (nominal moment Mn) of the cross section in a section where a negative moment is applied at the end of the precast wall.

8 is a view showing the stress, strain and strength of the cross section of the cutting reinforcing bar as one embodiment of the present invention.

The object of the present invention is to move the position of the critical region to the inside of the member by applying a cutting reinforcing bar to adjust the strength of the flexural reinforcement at any position, the settlement of the reinforcement by moving the yield point of the reinforcement to the arbitrary position It is to reduce the length of the part purchase.

Cutting reinforcing barning means adjusting the bending strength at any point by cutting some of the reinforcing bars in the bent bar at a certain point and spaced apart by a predetermined length.

The above object of the present invention is characterized in that in the construction member having a plurality of bending members, the protruding length of the bending member can be reduced by joining the cutting reinforcing bar is installed in the critical region located at the end of the construction member. It can be achieved by the construction member. Preferably, the above-described flexural member should be mounted with reinforcing bars, and if the member is manufactured by rebar reinforcement and precast concrete method of field reinforced concrete member by applying this method, the site construction work and factory P.C. The productivity of the member can be improved.

Still another object of the present invention is a construction structure comprising a support member for supporting a predetermined force and at least one construction member installed while being supported by the support member and having a plurality of bending members, wherein an end portion of the construction member is provided. And it can be achieved by a construction structure, characterized in that the bending length of the bending member is installed in the critical region located in the middle portion can be reduced by the protruding length of the bending member.

Hereinafter, the present invention will be described more preferably with reference to the drawings. 3 is a cross-sectional view illustrating the relationship between a critical section of a construction member and a bending member placed near the construction member. FIG. When the force acts in the direction shown, a critical section showing the location of the cross section where the magnitude of the moment and the strength of the member are the same appears as a dotted line.

Since the bending members 41 to 47 must maintain a fixed fixing length from the critical area toward the outside of the member, as shown in FIG. 3, the bending member which is placed near the critical area existing near the end of the member has a considerable protruding length ( Length of the bending member that is placed outside of the member). Typically, the construction structure uses a reinforcing bar as a bending member, the reinforcing bar is installed in the critical region located near the end of the member is referred to as 'main bar'. In the case of FIG. 3, the representative 'root' may be referred to as the bending member 41.

Figure 4 shows a cross-sectional view of the building structure of one embodiment of the present invention subjected to cutting rebar bonding. FIG. 4 shows one pillar 10 and a beam 20 installed on the right side thereof. In this case, it is assumed that a force in the direction as shown is applied to the beam 20. The critical section on the beam 20 with respect to the force in the direction shown is a parabolic shape shown in dashed lines, which shows that the maximum bending moment occurs at the tip and center of the beam 20. Can be. In the conventional construction structure as shown in Figure 1 should be provided with a bending member provided with a constant fixing length from the critical area, but moving the position of the critical area to the inside of the member can reduce the fixing length from the critical area. Thus, the method for moving the position of the critical region to the inside of the member, according to the present invention, by applying a cutting reinforcing bar to reduce the adhesion between the bending member and the concrete at any position, the yield point of the reinforcing bar to the arbitrary position By moving, the reinforcement length of the reinforcing bar is reduced.

That is, as shown in FIG. 4, the bending member 31-2, which is moved to the critical region existing at the tip of the member, is cut from the critical region in the inner region of the member, and the reinforcing cut joint is joined to the fixing bending member 31-1. This makes it possible to move the yield region into the interior of the member. As a result, the fixing bending member 31-1 is provided with the fixing length Ld from the rebar cutting joint, so that the protruding length Pd of the bending member protruding to the outside of the member can be reduced.

By adjusting the flexural strength by cutting and connecting the bending members 31-1 and 32-2 to each other in such a manner, when the force is applied, the fracture point is formed in the cutting reinforcing bar joining area, that is, moved to the area inside the beam 20. Will have an effect. If the bending member 31-1 is provided with the minimum extension length " Ld " of the bending member from this breakdown point, the total length " Ld " of the bending member 31-1 coming out of the beam 20 is You can configure it considerably shorter than "Ld".

In the description of FIG. 4, the structure of the column 10 and the beam 20 is described. However, this is only an example, and the connection between the segmented members in the single beam and the slab member and the beam and column, the small beam and the large beam, It can be applied to various structures such as slabs and walls, slab and beam constructions.

5 shows one embodiment of cutting rebar splicing. To adjust the flexural strength by cutting several necessary reinforcing bars at a certain area, Figure 5 (a) is a reinforcing bar cutting method for cutting a certain number of reinforcing bars at any point, Figure 5 (b) is a part of the rebar 5 to be spaced apart by a predetermined distance by cutting in a certain interval, Figure 5 (c) is a method of cutting and staggering some reinforcing bars and Figure 5 (d) is a method of cutting a partial cross section of each of the reinforcing bar of several rebars, respectively It is shown.

6 shows an embodiment in which the present invention is applied to a pier and a pier deck. In order to form a bridge, the piers are installed between the piers 61 and 62. Since the distances between the piers are far apart, it is difficult to form the piers on the upper part of the piers with a single member. 6 (a) shows that the two upper plates 51 and 52 are formed on the piers 61 and 62, and shows the critical region at this time. 6 (b) and 6 (c) are enlarged views of region A of FIG. 6 (a), respectively, and FIG. 6 (b) shows a case in which no cutting reinforcing bars are applied. The case where the cut reinforcing steel joint of is applied to the pier upper plate is shown, respectively. 6 (b) shows that the distance between the two upper plates 51 and 52 should be spaced apart by S1 in order to secure the joint length Ld of the reinforcing bar. In the case where the cutting reinforcing bar joints of the present invention are applied to the bridge top plates 51 and 52, since the break point moves to the cutting reinforcing bar joint sites, as shown in FIG. The separation distance can be reduced as S2. This concept is also applicable to those skilled in the art, as shown in FIG. 6 (d), even when the pier plate is applied to three members represented by 51, 52, and 53. FIG.

7 is a graph showing the relationship between the moment (moment Mu / φ applying the load factor and the reduction factor) and the resistance moment (nominal moment Mn) of the cross section in a section where a negative moment is applied at the end of the bending member. In the figure, the position of Xo represents the end of the member, and X3 represents the point where the parent moment is changed to the static moment. The moment distribution should be curved, but the moment distribution is shown in a straight line because the distribution of moment is almost linear at the end. In the figure, the section indicated by Ldn is a section to which the cutting rebar junction is applied. Therefore, in this section, the magnitude of the resistance moment Mn becomes smaller and becomes equal to Mu / φ. Therefore, the time point X1 where the cutting bar joint is applied becomes the critical region. In the figure, α and β represent the ratio of the nominal moment at the position of Xo to the value of Muo / φ and the ratio of the nominal moment at the position of X1, respectively, and Ldn represents the cutting rebar separation distance. Therefore, since the end of the member has a safety factor of α, the breakdown of the member occurs first at the position of X1. The number and length of reinforcing bars to which the cutting reinforcing bar is to be applied are determined according to the values of α and β.

The stress and strain of the cross section in which the cutting reinforcing bars are shown as shown in FIG. 6. In FIG. 8, (a) shows the cross section, (b) shows the deformation, and (c) shows the proof strength. Using equilibrium conditions by compression and tension in FIG.

In Equation 1

: Compressive strength of concrete

a: equivalent rectangular compressive stress block depth

b: width of the compressed surface of the member

c: distance from compression edge to neutral axis

: Yield strength of rebar

β1: equivalent compression block coefficient

Asb: Cross section of connecting rebar

Asd: Cross section of cutting bar (Asd = 0 for complete cutting)

: Deformation of connecting rebar

: Deformation of cutting rebar

: Deformation of concrete

Es: modulus of elasticity of rebar

m: number of connecting bars

n: number of cutting rebar

Means.

Since the position of the critical region can be moved to the inside of the joint at the end of the member and any intermediate part by the construction member having the cutting reinforcing bar connection and the construction structure using the same, the fixing length as long as the length moved inward Since it can be secured in advance, it is possible to reduce the length of the reinforcing bar that must protrude from the end of the member and any joint.

Therefore, the reinforcement workability, workability, manufacturability, and transportability of the bending member can be improved, and as a result, economic efficiency can be expected.

Claims (6)

In the construction member having a plurality of bending members, The bending member installed in the critical region located in the construction member is cut and cut in the critical region is provided with the bending member spaced apart from each other by a predetermined distance to reduce the projecting length of the construction member, characterized in that absence. In the construction member having a plurality of bending members, And the bending member installed in the critical region positioned in the construction member is cut in part of the cross section in the critical region, thereby reducing the protruding length of the bending member. The construction member according to claim 1 or 2, wherein the construction member is produced by a precast method. In a construction structure comprising a support member for supporting a predetermined force and at least one construction member having a plurality of bending members installed while being supported by the support member, And a construction member capable of reducing the protruding length of the bending member by providing the bending member installed in the critical region positioned in the construction member with the bending members cut and cut at the critical region spaced apart from each other by a predetermined distance. Construction structure, characterized in that. In a construction structure comprising a support member for supporting a predetermined force and at least one construction member having a plurality of bending members installed while being supported by the support member, And a construction member capable of reducing the protruding length of the bending member by cutting a partial cross section of the bending member installed in the critical region located in the construction member. The method according to claim 4 or 5, At least one of the support member and the construction member is generated by a precast method.