US20110225927A1

US20110225927A1 - Steel-concrete composite beam and construction method using same

Info

Publication number: US20110225927A1
Application number: US13/124,997
Authority: US
Inventors: Jeom-Han Kim; Young-Sang Cho; Eun-Ho Jeong; Kyoung-Hun Lee
Original assignee: CROSS STRUCTURAL CONSULTANT CO Ltd
Current assignee: CROSS STRUCTURAL CONSULTANT CO Ltd
Priority date: 2008-10-20
Filing date: 2009-07-08
Publication date: 2011-09-22
Also published as: WO2010047461A1; KR100888941B1

Abstract

A steel-concrete composite beam includes a long rectangular steel frame; concrete members installed at only both ends of the steel frame, excluding a center portion thereof; a prestressable reinforcement buried in the concrete member; and a stirrup reinforcement arranged to the concrete member with a regular gap thereto to surround a lower flange of the steel frame.

Description

TECHNICAL FIELD

The present invention relates to a steel-concrete composite beam and a construction method using the same. More particularly, the present invention relates to a steel-concrete composite beam in which concrete members are installed at only both ends of the beam, excluding the center portion thereof, to reduce self weight and in which a support member is provided at a steel frame so that a deck plate may be installed thereto during slab construction for convenient installation and construction of the deck plate, and a construction method using the same.

BACKGROUND ART

Korean Patent Registration No. 0761786 discloses a concrete composite shape steel beam in which a steel frame with an H-shaped section and a concrete are integrally formed to reduce a height of one story.
This concrete composite shape steel beam is precast at a factory and then transported to a construction spot to be assembled there.
However, the concrete composite shape steel beam disclosed in the above patent has H-shaped steel and concrete member over the entire length of the beam, resulting in high material costs and difficulty in handling and construction due to heavy weight.
Korean Patent Registration No. 0808057, entitled “a composite member and a construction method of a structure using the same”, discloses a composite member in which structural steels are installed at only both ends of a concrete member to reduce self weight and decrease construction cost.
However, the composite member configured as above has a relatively weak strength since a steel frame is not provided to the center portion thereof. In addition, if the beam has great length, it is not easy to endure a stress moment applied in a vertical direction. Thus, a lower structure such as a supporting post or a support should be installed separately.

DISCLOSURE

Technical Problem

The present invention is designed to solve the problems of the prior art, and therefore it is an object of the present invention to provide a steel-concrete composite beam, which is configured to sufficiently resist a bending moment during construction work and have a reduced overall weight so as to ensure easy handling and construction.
Another object of the present invention is to provide a steel-concrete composite beam having an improved configuration to ensure easy installation of a deck plate during slab construction.
Furthermore, another object of the present invention is to provide a method for constructing a building by using the steel-concrete composite beam as mentioned above.

Technical Solution

In order to accomplish the above object, the present invention provides a steel-concrete composite beam, which includes a long rectangular steel frame; concrete members installed at only both ends of the steel frame, excluding a center portion thereof; a prestressable reinforcement buried in the concrete member; and a stirrup reinforcement arranged to the concrete member with a regular gap thereto to surround a lower flange of the steel frame.
Preferably, the concrete member is formed to bury a part of a lower end of the lower flange and a web of the steel frame so that an upper flange of the steel frame is located to be higher than an upper surface of the concrete member. The steel-concrete composite beam further comprises a support member formed to extend from the center portion of the steel frame, where the concrete member is not formed in a lateral direction, and an upper surface of the support member has the same height as the upper surface of the concrete member.
More preferably, the support member includes a fixed side fixed to the web of the steel frame; and an installing side extending in parallel with the upper flange in a lateral direction of the steel frame.
As an alternative, the concrete member is formed to bury even an upper flange of the steel frame so that an upper surface of the upper flange of the steel frame is located at the same height as an upper surface of the concrete member.
In another aspect, the present invention provides a method for constructing a building, which includes installing a pillar member and connecting the above steel-concrete composite beam to the pillar member.

Advantageous Effects

The steel-concrete composite beam according to the present invention allows easy handling and transportation due to its light weight since concrete members are partially formed at only both ends of the beam, excluding the center portion thereof.
Nevertheless, a steel frame is provided over the entire length of the steel-concrete composite beam of the present invention, which allows the beam to effectively resist a bending moment concentrated on the center portion and give sufficient design strength.
Further, according to the steel-concrete composite beam of the present invention, a deck plate may be installed to a support member or directly installed to an upper flange of the steel frame during slab construction, which ensures very convenient construction and effectively lowers the height of a story.

DESCRIPTION OF DRAWINGS

Other objects and aspects of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawing in which:

FIG. 1 is a perspective view schematically showing a steel-concrete composite beam according to a preferred embodiment of the present invention;

FIG. 2 is a front view schematically showing the steel-concrete composite beam according to the preferred embodiment of the present invention;

FIG. 3 is a plane view schematically showing the steel-concrete composite beam according to the preferred embodiment of the present invention;

FIG. 4 is a sectional view taken along the line A-A′ of FIG. 1;

FIG. 5 is a sectional view taken along the line B-B′ of FIG. 1;

FIG. 6 is a perspective view schematically showing a steel-concrete composite beam according to another embodiment of the present invention;

FIG. 7 is a front view schematically showing the steel-concrete composite beam according to another embodiment of the present invention;

FIG. 8 is a plane view schematically showing the steel-concrete composite beam according to another embodiment of the present invention;

FIG. 9 is a sectional view taken along the line C-C′ of FIG. 6;

FIG. 10 is a perspective view showing an example in which the steel-concrete composite beam according to the preferred embodiment of the present invention is connected to a pillar member;

FIGS. 11 and 12 illustrate that a slab is constructed by using the steel-concrete composite beam according to the preferred embodiment of the present invention; and

FIG. 13 is a front view showing a steel-concrete composite beam according to another embodiment of the present invention.

BEST MODE

FIGS. 1 to 5 schematically show a steel-concrete composite beam according to a preferred embodiment of the present invention. FIG. 1 is a perspective view showing the steel-concrete composite beam according to the present invention, FIG. 2 is a front view thereof, FIG. 3 is a plane view thereof, and FIGS. 4 and 5 are sectional views respectively taken along lines A-A′ and B-B′ of FIG. 1.
Referring to FIGS. 1 to 5, the steel-concrete composite beam according to the present invention includes a long rectangular steel frame 10, and concrete members 12 installed at both ends of the steel frame 10, excluding a center portion of the steel frame 10.
The steel frame 10 is long enough to be hanging between pillars of a building to be constructed. The length of the steel frame 10 may be changed variously if necessary.
Also, as shown in the sectional views of FIGS. 4 and 5, the steel frame 10 is a steel with an I- or H-shaped section. The steel frame 10 includes a pair of upper and lower flanges 14 and 16 formed in parallel, and a web 18 connected between the upper and lower flanges 14 and 16.
According to the present invention, the concrete member has a hexahedral or another polyhedral shape and is installed at only both ends of the steel frame 10, excluding the center portion thereof. In this embodiment, the concrete member 12 is formed so that the lower flange 16 and the web 18 of the steel frame 10 are partially buried therein. Thus, the upper flange 14 of the steel frame 10 is located to be higher than the upper surface of the concrete member 12.
Though not shown precisely in the drawings, a plurality of stud members is formed at the side of the web 18 buried in the concrete member 12 so as to improve a coupling force between the web 18 and the concrete member 12.
Also, the front end of the steel frame 10 is not buried in the concrete member 12 but protrudes out of the concrete member 12 so that the front end of the steel frame 10 may be connected to a pillar member as explained later. For this purpose, a plurality of coupling holes 20 may be formed in the front end of the steel frame 10.
In the present invention, the length of the center portion of the steel frame 10, to which the concrete member 12 is not installed, may be suitably set in consideration of the length and weight of the beam. Preferably, the length of the center portion of the steel frame 10 is greater than the sum of the lengths of the concrete members 12 installed at both ends of the steel frame 10.
For example, a ratio of the length of the center portion to the entire length of the steel-concrete composite beam may be 0.5 to 0.8, but the present invention is not limited thereto.
Preferably, the steel-concrete composite beam of the present invention includes at least one prestressable reinforcement 22 arranged in a longitudinal direction thereof.
More preferably, the part of the prestressable reinforcement 22 buried in the concrete member 12 may be buried in a prestressable state by a pre-tensioning method.
In this case, the sectional area of the concrete member 12 may be increased, and the increased sectional area may give an effective resistance against a tensile stress caused by a load.
As another alternative, the prestressable reinforcement may not be provided to the center portion, excluding the concrete members 12, as shown in FIG. 13.
Also, the prestressable reinforcement may be buried in the concrete member 12 while being bent upwards, as shown by dotted lines in FIG. 13.
In addition, a stirrup reinforcement 24 is installed to the concrete member 12 with a regular gap thereto. The stirrup reinforcement 24 is buried in the concrete member 12 to surround the lower flange 16 of the steel frame 10. Both ends of the stirrup reinforcement 24 are exposed on the upper surface of the concrete member 12.
Preferably, the stirrup reinforcement 24 is arranged to be in contact with the prestressable reinforcement 22. More preferably, the stirrup reinforcement 24 is arranged to surround the lower flange 16 of the steel frame 10 and the prestressable reinforcement 22.
The steel-concrete composite beam according to the present invention includes a support member 26 for allowing a deck plate to be installed during slab construction.
Specifically, the support member 26 extends from the center portion of the steel frame 10, where the concrete member 12 is not formed in a lateral direction. More specifically, the support member 26 is an L-shaped angle as shown in FIG. 5, which includes a fixed side 26 a fixed to the web 18 of the steel frame 10 and an installing side 26 b extending in parallel with the upper flange 14 in a lateral direction of the steel frame 10.
At this time, the upper surface of the support member 26, namely the upper surface of the installing side 26 b is at the same height as the upper surface of the concrete member 12. As described later, the deck plate may be installed to the upper surface of the support member 26 and the upper surface of the concrete member 12 at the same time.
FIGS. 6 to 9 schematically show a steel-concrete composite beam according to another embodiment of the present invention. Here, like reference numerals designate like components with like functions in comparison to the former drawings.
The steel-concrete composite beam of this embodiment includes a steel frame 10 and concrete members 12′ formed at only both ends of the steel frame 10, excluding the center portion thereof.
Also, the concrete members 12′ are configured to bury even the upper flange 14 of the steel frame 10. At this time, the upper surface of the upper flange 14 of the steel frame 10 is located at the same height as the upper surface of the concrete member 12′.
Since the upper flange 14 of the steel frame 10 is formed at the same height as the concrete member 12′ in this embodiment, a deck plate may be installed on the upper surface of the upper flange 14 during slab construction. Thus, the upper flange 14 of the steel frame 10 plays the same role as the support member 26 of the former embodiment. For this reason, the steel-concrete composite beam of this embodiment does not need a separate support member.
Therefore, the steel-concrete composite beam of this embodiment has a simple configuration and a decreased weight.
Now, a method for constructing a building by using the steel-concrete composite beam according to the preferred embodiment of the present invention, which is configured as mentioned above, will be described.
The steel-concrete composite beam according to the present invention is precast and fabricated at a factory. After the steel frame 10 and the prestressable reinforcement 22 as well as the stirrup reinforcement 24 are arranged, the concrete members 12 may be placed at only both ends thereof to form a beam. At this time, the prestressable reinforcement 22 may be buried in the concrete member 12 by means of a pre-tensioning method.
The steel-concrete composite beam fabricated as above is transported to a construction spot and then installed there.
First, prior to installing the steel-concrete composite beam, a pillar member is installed at a location where a pillar of a building will be formed. The pillar member may be constructed by using H-shaped steel or a precast concrete pillar. In the following description and appended claims, the pillar member is defined to be inclusive of various kinds of pillars such as H-shaped steel.
FIG. 10 shows that the pillar member 100 is installed by using H-shaped steel. If the pillar member 10 is completely installed, the steel-concrete composite beam of the present invention is connected to the pillar member 100 subsequently.
For this purpose, a connection bracket 112 having a plurality of coupling holes 110 is installed to the pillar member 100 in advance. Thus, as shown in the figure, the front end of the steel frame 10 of the steel-concrete composite beam according to the present invention is aligned to the connection bracket 112, and then coupling bolts 114 are inserted into the coupling holes 110 and 20 and fastened with nuts 116.
In another embodiment of the present invention, the steel-concrete composite beam may be directly fixed to the pillar member 100 by welding. In other words, the front end of the steel frame 10 may be welded to the pillar member 100 directly or with a mediate member or an auxiliary member being interposed between them.
As described above, the steel-concrete composite beam may be connected to the pillar member in various ways, without being limited to the above.
If the steel-concrete composite beam is completely connected to the pillar member 10 as described above, a deck plate 130 is installed on the composite beam and a slab reinforcement 132 is arranged thereon. The deck plate 130 plays a role of a mould for the slab. The deck plate 130 is already well known in the art and thus not described in detail here.
According to the present invention, the deck plate 130 is installed to be held by the edge of the upper surface of the concrete member 12 of the steel-concrete composite beam. At the same time, in the center portion of the beam, the deck plate 130 is installed to be held on the upper surface of the support member 26, specifically, on the installing side 26 b. FIG. 11 shows the deck plate 130 installed on the upper surface of the support member 26.
By the above procedure, the deck plate is installed to cover a region between beams. In the steel-concrete composite beam of this embodiment, the upper surface of the concrete member 12 is located to be lower than the upper surface of the steel frame 10, which may reduce an entire height of one story and a depth of a beam.
Further, if necessary, a mould may be suitably installed at the connection region between the pillar member 100 and the beam.
Subsequently, if concrete is poured, placed and cured on the deck plate 130, a slab using the steel-concrete composite beam according to the present invention is completely constructed.
FIG. 12 shows a process of constructing a slab by using the steel-concrete composite beam according to the embodiment shown in FIGS. 6 to 9.
Even in the case of the steel-concrete composite beam of this embodiment, the deck plate 130 is installed on the edge of the upper surface of the concrete member 12′.
Also, in this embodiment, the upper surface of the upper flange 14 of the steel frame 10 is located at the same height as the upper surface of the concrete member 12′. Thus, the deck plate 130 is directly installed to the upper surface of the upper flange 14 as shown in FIG. 12.
Finally, concrete is placed and cured in the same way as in the former embodiment.

Claims

1. A steel-concrete composite beam, comprising:

a long rectangular steel frame;

concrete members installed at only both ends of the steel frame, excluding a center portion thereof;

a prestressable reinforcement buried in the concrete member; and

a stirrup reinforcement arranged to the concrete member with a regular gap thereto to surround a lower flange of the steel frame.

2. The steel-concrete composite beam according to claim 1,

wherein the concrete member is formed to bury a part of a lower end of the lower flange and a web of the steel frame so that an upper flange of the steel frame is located to be higher than an upper surface of the concrete member,

wherein the steel-concrete composite beam further comprises a support member formed to extend from the center portion of the steel frame, where the concrete member is not formed, in a lateral direction, and

wherein an upper surface of the support member has the same height as the upper surface of the concrete member.

3. The steel-concrete composite beam according to claim 2, wherein the support member includes:

a fixed side fixed to the web of the steel frame; and

an installing side extending in parallel with the upper flange in a lateral direction of the steel frame.

4. The steel-concrete composite beam according to claim 1, wherein the concrete member is formed to bury even an upper flange of the steel frame so that an upper surface of the upper flange of the steel frame is located at the same height as an upper surface of the concrete member.

5. The steel-concrete composite beam according to claim 1, wherein a front end of the steel frame is not buried in the concrete member but protrudes out, and a plurality of coupling holes is formed in the front end of the steel frame.

6. The steel-concrete composite beam according to claim 2, wherein a front end of the steel frame is not buried in the concrete member but protrudes out, and a plurality of coupling holes is formed in the front end of the steel frame.

7. The steel-concrete composite beam according to claim 3, wherein a front end of the steel frame is not buried in the concrete member but protrudes out, and a plurality of coupling holes is formed in the front end of the steel frame.

8. (canceled)

9. The steel-concrete composite beam according to claim 4, wherein a front end of the steel frame is not buried in the concrete member but protrudes out, and a plurality of coupling holes is formed in the front end of the steel frame.

10. The steel-concrete composite beam according to claim 1, wherein a length of the center portion of the steel frame, where the concrete member is not formed, is greater than a sum of the lengths of the concrete members.

11. The steel-concrete composite beam according to claim 2, wherein a length of the center portion of the steel frame, where the concrete member is not formed, is greater than a sum of the lengths of the concrete members.

12. The steel-concrete composite beam according to claim 3, wherein a length of the center portion of the steel frame, where the concrete member is not formed, is greater than a sum of the lengths of the concrete members.

13. The steel-concrete composite beam according to claim 4, wherein a length of the center portion of the steel frame, where the concrete member is not formed, is greater than a sum of the lengths of the concrete members.

14. The steel-concrete composite beam according to claim 1, wherein a plurality of stud members is formed at a side of a web of the steel frame, which is buried in the concrete member.

15. The steel-concrete composite beam according to claim 2, wherein a plurality of stud members is formed at a side of a web of the steel frame, which is buried in the concrete member.

16. The steel-concrete composite beam according to claim 3, wherein a plurality of stud members is formed at a side of a web of the steel frame, which is buried in the concrete member.

17. The steel-concrete composite beam according to claim 4, wherein a plurality of stud members is formed at a side of a web of the steel frame, which is buried in the concrete member.

18. A method for constructing a building, comprising:

installing a pillar member; and

connecting the steel-concrete composite beam according to claim 1 to the pillar member.

19. A method for constructing a building, comprising:

installing a pillar member; and

connecting the steel-concrete composite beam according to claim 2 to the pillar member.

20. A method for constructing a building, comprising:

installing a pillar member; and

connecting the steel-concrete composite beam according to claim 3 to the pillar member.

21. A method for constructing a building, comprising:

installing a pillar member; and

connecting the steel-concrete composite beam according to claim 4 to the pillar member.