KR20060083776A - Steel permanent formwork beam with cover type shear binding plate and steel concrete composite beam using it - Google Patents

Abstract

The present invention is a steel member used to form a steel concrete composite beam does not need a separate formwork for placing concrete, the beam and the slab maintains a structurally stable joint relationship without a separate shear connector, the concrete filled inside The present invention relates to a steel permanent formwork beam and a steel concrete composite beam using the same so that a triaxial stress state can exhibit a greater strength.

To this end, the steel permanent formwork according to the present invention, the bottom portion 11, both side wall portions 12, 12 'formed from the bottom portion 11 and the outer side from the tip of the side wall portions 12, 12', respectively A channel-shaped steel beam 10 configured to have an upper portion formed by connecting portions 13 and 13 'formed to extend; Both ends are joined to the connecting portions 13 and 13 'of the channel-shaped steel beam 10, and a plurality of spaces are formed so that concrete can be tightly filled in the space consisting of the bottom portion 11 and both side wall portions 12 and 12'. Two holes 22 are perforated and embedded in slab concrete, characterized in that it comprises a cover-type shear confinement plate 20 bent into a predetermined shape to function as a shear connector.

Composite beam, TSC beam, interlocking key, deck plate, stud, shroud shear plate

Description

Steel beam with capping shear connector and Composite Beam using the steel beam

1 is a perspective view of a steel permanent formwork beam according to an embodiment of the present invention.

Figure 2a to 2c is a cross-sectional view showing an example in which the cover type shear binding plate according to the present invention is bonded to the steel permanent formwork beams.

Figure 3a to 3d is a perspective view showing a variant of the cover shear plate in the permanent steel formwork beam according to the present invention.

Figure 4a to 4c is a perspective view showing the engagement key applied to the steel permanent formwork beam according to the present invention.

5 is a cross-sectional perspective view showing a state in which a steel concrete composite beam is formed using a steel permanent formwork beam according to the present invention.

6 is a cross-sectional view showing a state in which a steel concrete composite beam is formed by bonding a deck plate to a steel permanent formwork beam according to the present invention.

Figure 7a is a perspective view of a conventional TSC beam.

Figure 7b is a cross-sectional view showing a conventional TSC beam.

<Explanation of Signs of Major Parts of Drawings>

10 steel permanent formwork beam 11: bottom

12, 12 ': side wall 13,13': connection

20: cover type shear binding plate 22: hole

28: connection portion 30: engagement key

31: steel plate 32: hole

34: plate 36: rebar

50: slab concrete 52, 54: slab reinforcement

60: beam concrete 70: deck plate

The present invention relates to a steel permanent formwork beam having a sheath-type shear restraint plate for implementing a steel concrete composite beam (steel composite member) synthesized with a steel beam and field-actuated concrete, and a steel concrete composite beam using the same as a structural element.

The steel concrete composite beam is made of steel beam and reinforced concrete to behave as a single member, so that most of the compressive stress is applied to concrete when the bending moment is applied, and the tensile stress is applied to the steel. It is possible to secure the floor space of building structures or the geometry of bridge structures, to make long span structures by increasing the resistance strength and resistance stiffness of beam section, and to increase the ultimate performance and deformation performance.

H-shaped steel, which is generally used to implement steel concrete composite beams, is a member cross section that effectively resists tensile and compressive forces caused by bending in terms of steel usage. Since the neutral axis of the composite section moves to the upper flange side, the concrete slab bears most of the compressive force, so the upper flange is used as an inefficient resistance section. In addition, since the performance of the composite beam member is excellent in terms of strength evaluation, it is applied to a long span, but the stiffness of the cross section is relatively small, indicating problems of usability such as excessive deflection and vibration.

In order to solve this problem, a steel-reinforced concrete beam (SRC beam) has been developed to surround the exterior of H-beams of composite beams with reinforced concrete. SRC beam has the advantages of excellent strength and stiffness of the cross section, but its own weight is very increased, so it requires a close attention to formwork and copper construction during site construction. In addition, there is no contribution of concrete surrounding H-shaped steel to tensile stress occurring in the lower section of the beam member in the constant moment section. Therefore, it can be called an inefficient structural section, and the concrete bending crack is visible to the naked eye. have.

TSC beams are known to solve the problems of inefficiency and usability of upper flanges in composite beams using H-beams as described above, and problems of workability and cross section inefficiency in steel reinforced concrete beams. .

As shown in FIGS. 7A and 7B, the TSC beam is composed of the lower steel plate 11, the web steel sheets 12 and 12 ′ and the upper steel plates 13 and 13 ′, and each steel plate is integrated to have a resistance to working external force. . At this time, the upper steel plate (13, 13 ') is provided with a stud (25) for resisting the horizontal shear force at the interface with the concrete slab 50 and the composite beam behavior. In addition, when tensile cracks are generated in the lower concrete 61 inside the steel formwork 10 due to the bending moment, the composite sheet cross-sectional strength may not be reached and may be destroyed, so the lower steel sheet 11 may be controlled to control the tensile cracking. Install studs 15 on the In addition, the top of the TSC beam to prevent the spread of the web steel plate (12, 12 ') when placing concrete, and attaching the through-bolt or section steel (20) for fixing the width for ease of upper slab operation. Reference numeral '55' represents slab formwork, and '52' and '54' represent slab reinforcing bars.

However, in the case of the TSC beam having the above-described configuration, since the stud 25 used as the shear connecting material is a flexible connecting material, the effect of perfect synthesis between the dissimilar materials, that is, the interface between the steel and the concrete slab is reduced, and the rigidity of the stud 25 is insufficient. As the relative slip between steel and concrete occurs at the interface, it tends to break without reaching the material strength and sufficient deformation performance of the lower steel sheet 11.

In addition, the compressive force is generated in the upper concrete 62 due to the vertical concentrated load or the bending moment acting on the composite member. The compressive force expands the upper concrete 62 (at right angles to the member) to open the web steel sheets 12 and 12 '. It is not effective for the stability of the member because of the phenomenon of causing it. In the state before the concrete 60 is placed inside the TSC beam, the open cross section causes deformation of the web steel sheets 12 and 12 'by lifting work by a crane and load during construction by an operator or construction material. It is easy to cause geometric instability of the cross section.

In addition, a stud (15), which is a shear connector, is disposed for the purpose of preventing slip between the filled concrete and the lower steel plate inside the TSC beam. However, the rigidity of the stud (15) and the projected area of the concrete acupressure resistance are small, so that the tension of the lower concrete (61) is reduced. The effect of restraint resistance on cracking cannot be expected. That is, after a certain load, the lower steel plate under the neutral axis reaches yield strength and causes tensile strain.The inner lower concrete 61 cannot have the same level of strain as the lower tensile strain of the steel, so that the lower surface of the steel sheet 61 cannot be attached to the surface and the tensile crack. Relative slip occurs. In order to suppress such relative slip deformation, the interloacking action should be sufficiently induced between the inner lower concrete 61 and the lower steel plate 11. The studs are connected to the lower concrete 61 filled inside the TSC beam as a flexible connector. There is a problem that can not exert sufficient restraint pressure effect.

The present invention has been made in view of the above-described problems of the TSC beam, the cross section is prevented from opening the vertical load such as construction load, steel permanent formwork beam and steel concrete using the improved composite effect between the steel and concrete slab It is an object to provide a composite beam.

In addition, the present invention solves the problem that the sub-neutral axis of the composite section does not reach the complete plasticization of the steel sheet material due to the slip between the concrete filled in the interior of the beam and the bottom of the beam, the concrete filled in the interior of the beam It is an object of the present invention to provide steel permanent formwork beams and steel concrete composite beams using the same.                         

In addition, the present invention provides a steel permanent formwork beam having an interloacking key installed so that a sufficient acupressure effect and shear effect between the bottom of the beam and the internal concrete is generated to reach a sufficient plastic deformation It is an object to provide a steel concrete composite beam using the same.

Other objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

1 is a perspective view showing a steel permanent formwork beam according to an embodiment of the present invention, Figures 2a to 2c is a cross-sectional view showing an example in which the cover-type shear binding plate according to the invention bonded to the steel permanent formwork beam, Figures 3a to 3d is a perspective view showing modified examples of the cover shear plate in the steel permanent formwork according to the present invention, Figures 4a to 4c is a perspective view showing an engagement key applied to the steel permanent formwork according to the present invention.

As shown in FIG. 1, the steel permanent formwork beam 1 according to the present invention includes a bottom part 11, two side wall parts 12 and 12 ′, and a connection part 13 and 13 ′ so that the upper part is opened. Both channel ends are joined to one channel-shaped steel beam 10 and the connecting portions 13 and 13 'of the channel-shaped steel beam 10, and a plurality of holes 22 are drilled and bent into a predetermined shape. The cover type shear confinement plate 20 and an engagement key 30 joined to the bottom 11 of the channel steel beam 10.

The channel steel beam 10 may be formed by bending a single steel sheet to form a bottom portion 11, both side wall portions 12 and 12 'and a connecting portion 13 and 13', and then forming them into separate steel sheets and then welding them. It can also be configured.

The channel-shaped steel beam 10 configured as described above becomes a formwork for laying concrete, and has the same function as reinforcing steel and shear reinforcing steel in reinforced concrete beams, and forms a composite beam that resists external force with concrete filled inside. Done. And the connecting portion 13, 13 "of the channel-shaped steel beam 10 will function as formwork pedestal or deck plate pedestal for slab concrete casting.

The cover type shear binding plate 20 is coupled to both ends 13 and 13 ′ of the steel beam 10 to constrain the opening of the steel beam 10, and to the channel-shaped steel beam 10. As a joining method, as shown in FIG. 2A, the sheath-type shear restraint plate 20 is welded to the connecting portions 13 and 13 'of the channel-shaped steel beam 10, or as shown in FIG. 2B. A joint 28 is further formed on the shear confinement plate 20 to be bolted to the joints 13 and 13 ′, or a through bolt passing through the channel-shaped steel beam 10 as shown in FIG. 2C. can do.

The cover type shear confinement plate 20 forms a plurality of holes 22 to fill the concrete tightly in the channel-shaped steel beam 10 and to penetrate the slab rebar. At this time, the hole 22 may be perforated so that one side is opened as shown in FIG. 3D so that the slab reinforcing bar can be easily inserted and disposed.

In addition, the cross section is a trapezoidal cross section having a bottom plate 24 and two inclined plates 26 that are bent so as to withstand the work load during slab reinforcement work and concrete pouring work and are embedded in slab concrete to function as shear connectors. do. However, the cross-sectional shape of the cover type shear binding plate 20 is not limited to this, and have a triangular cross section as shown in Figure 3a, or have a semi-circular cross section as shown in Figure 3b, or in Figure 3c It may be configured to have a rectangular cross section as shown.

The cover-type shear binding plate 20 configured as described above is divided into a plurality of openings of the channel-shaped steel beam 10 so as to be partially opened as shown in FIG. 1, and coupled to the channel-shaped steel beam 10 at predetermined intervals. Preferably, it may be formed of a single member having the same length as the length of the channel-shaped steel beam 10 may be joined to the channel-shaped steel beam 10.

The above-described sheath-type shear restraint plate 20 has both side wall portions of the channel-shaped steel beams 10 due to the working load acting on the channel-shaped steel beams 10 and the lateral pressure of concrete filled in the channel-shaped steel beams 10. It prevents (12, 12 ') from spreading and secures the stability of the cross section, and effectively realizes the composite beam behavior by resisting the horizontal and vertical shear forces at the interface between the channel steel beam 10 and the concrete slab without separate shear connector. Do it. And the hole 22 perforated in the cover-type shear binding plate 20 is embedded in the concrete has the effect of maximizing the in-plane shear force and dowel action (dowel action).

In the bottom portion 13 of the channel-shaped steel beam 10, an engagement key 30 is installed to generate a sufficient acupressure effect and shear effect between the bottom portion 13 and the internal concrete, and the engagement key 30 is illustrated in FIG. 4A. As shown in FIG. 3, the plurality of holes 32 are drilled at predetermined intervals on the steel sheet 31 having a predetermined width and length, and the diaphragm 34 is disposed at predetermined intervals between the plurality of holes 32. It is combined perpendicular to the longitudinal direction of the.

In this case, the reinforcement 36 may be further coupled to the hole 32 as illustrated in FIG. 4B, and may be further formed by bending both ends of the diaphragm 34 as illustrated in FIG. 4C.

The engagement key 30 configured as described above not only increases the bonding force with the concrete placed inside the channel-shaped steel beam 10 but also controls the tensile crack occurring in the concrete. In particular, the diaphragm 34 has a tensile crack generated in the concrete. It is very effective in suppressing this expansion. .

Hereinafter, a method of forming a steel concrete composite beam using the steel permanent formwork beam according to the present invention configured as described above will be described with reference to FIG.

First, the single steel sheet is bent to form the bottom portion 11, the side wall portions 12 and 12 'and the connecting portions 13 and 13', or they may be formed of separate steel sheets and then welded to fabricate the channel-shaped steel beam 10. And welding the engagement key 30 to the bottom portion 11, and then bringing the steel permanent formwork beam 1 produced by welding the cover type shear binding plate 20 to the connecting portions 13 and 13 '. In this case, the steel permanent formwork beams 1 can be handled in the same manner as the H-shaped steel beams, so that the joining with other members (steel column, girder) is easy for field work. The method of joining (bolt joining, welding joining) is used as it is.

Next, after installing the slab formwork in the connecting portion (13, 13 ') of the channel-shaped steel beam 10, the beam cone is reinforced to the beam and slab reinforcement (52, 54) and filled inside the channel-shaped steel beam (10) When the concrete and slab concrete are poured and cured simultaneously, the steel concrete composite beam and the slab concrete 50 are integrated.

At this time, when the deck plate is used instead of the slab formwork, as shown in Figure 6, the end of the deck plate 70 on the connecting portion (13, 13 ') of the channel-shaped steel beam 10, the connection portion 13 13 ') and the deck plate 70 by fastening the bolt to restrain the movement of the deck plate 70 can be carried out concrete pouring work.

The steel concrete composite beam completed by the above process does not need a separate formwork for beam concrete placing, and maintains a structurally stable joint relationship without a separate shear connector for the composite action of the beam and slab, and the cover type shear restraint The inner concrete surrounded by the plate 20 and the channel-shaped steel beam 10 is structurally triaxially stressed like the concrete filled in the steel pipe, thereby exhibiting a greater strength.

As described above, according to the present invention, a phenomenon in which the cross section is spread with respect to the vertical load is prevented, and the synthesizing effect at the interface between the steel and the concrete is improved without using a separate shear connector.

In addition, it is possible to prevent the occurrence of slip between the concrete filled in the steel permanent form beams and the bottom part, so that the steel beams below the neutral axis easily reach the plastic deformation, so that the plastic neutral axis can be easily formed. It can have a restraining effect.                     

In addition, the connection between the steel permanent formwork beam and the deck plate can be made simpler and more secure.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, various modifications and variations are possible without departing from the spirit and scope of the invention. Thus, the claims will cover any modifications or variations that fall within the spirit of the invention.

Claims (4)

Bottom portions 11, both side wall portions 12 and 12 'extending from the bottom portion 11, and connecting portions 13 and 13' extending outwardly from the distal ends of the side wall portions 12 and 12 ', respectively. A channel type steel beam 10 configured to be opened by the upper portion; Both ends are joined to the connecting portions 13 and 13 'of the channel-shaped steel beam 10, and a plurality of spaces are formed so that concrete can be tightly filled in the space consisting of the bottom portion 11 and both side wall portions 12 and 12'. Steel permanent formwork comprising ;; 22 shear holes perforated and buried in a predetermined shape to be buried in the slab concrete to function as a shear connector. The method of claim 1, In the bottom portion 11 of the channel-shaped steel beam 10, a plurality of holes 32 are drilled at predetermined intervals on a steel plate 31 having a predetermined width and length, and at predetermined intervals between the plurality of holes 32. Steel permanent formwork, characterized in that the engagement key 30 is further bonded to the plate 34 perpendicular to the longitudinal direction of the steel plate (31). The method according to claim 1 or 2, The cover shear shear plate 20 is a steel permanent formwork, characterized in that the cross-sectional shape is bent to have a trapezoidal shape, triangular shape, semi-circular shape or square shape. Bottom portions 11, both side wall portions 12 and 12 'extending from the bottom portion 11, and connecting portions 13 and 13' extending outwardly from the distal ends of the side wall portions 12 and 12 ', respectively. Both ends are joined to the channel-shaped steel beams 10 and the connection portions 13 and 13 'of the channel-shaped steel beams 10, the upper portions of which are opened, and the bottom portion 11 and both side wall portions ( 12, 12 ') and a plurality of holes 22 are drilled and embedded in the slab concrete to be filled in a tight space to cover the shear shear plate 20 bent into a predetermined shape to function as a shear connector and And a plurality of holes 32 joined to the bottom portion 11 of the channel-shaped steel beam 10 and drilled at predetermined intervals and diaphragms 34 coupled at predetermined intervals between the plurality of holes 32. Steel permanent formwork beam including the engaging key 30; Steel concrete composite beam, characterized in that the steel permanent form beam is filled with in-situ cast concrete including the concrete behaving with the steel permanent formwork beam.

Images