WO2008102955A1

WO2008102955A1 - Composite girder having connection structure of inclined members in composite girder with steel truss web using embedded t-type perfobond and such connection structure

Info

Publication number: WO2008102955A1
Application number: PCT/KR2008/000567
Authority: WO
Inventors: Kwang Soo Kim; Kwang Hoe Jung; Chung Wook Sim; Chul Hun Chung; Chang Su Sim; In Ho Yeo
Original assignee: Hyundai Engineering & Construction Co., Ltd.
Priority date: 2007-02-20
Filing date: 2008-01-30
Publication date: 2008-08-28
Also published as: KR100783256B1

Abstract

In a composite web truss girder that includes an upper flange and a lower flange formed of concrete and a web having a truss structure of a diagonal member formed of steel, a T-type shear connector is used to shear-connect the diagonal member to the upper flange or the lower flange at a panel point, at which the diagonal member and the upper flange or a lower flange are combined, thereby enhancing structural performance of the panel point without using a gusset plate.

Description

Description COMPOSITE GIRDER HAVING CONNECTION STRUCTURE

OF INCLINED MEMBERS IN COMPOSITE GIRDER WITH STEEL TRUSS WEB USING EMBEDDED T-TYPE PERFOBOND

AND SUCH CONNECTION STRUCTURE Technical Field

[1] The present invention relates to a composite web truss girder including upper and lower flanges formed of concrete and a web having a truss structure of a diagonal member formed of steel, and a connection structure of a panel point of the composite web truss girder at which the steel member and the upper and lower flanges are combined.

[2]

Background Art

[3] FIG. 1 is a schematic perspective view illustrating a bridge using a conventional composite web truss girder. As illustrated in the figure, a composite web truss girder

100 includes a web between an upper flange 101 and a lower flange 102, in which the web has a truss structure of a diagonal member 103 formed of steel. In such a composite web truss girder, it is very important how to configure a connection structure of a panel point at which the diagonal member 103 and the upper flange 101 or the lower flange 102 are combined.

[4] FIG. 2 is a schematic partial cross-sectional view illustrating the connection structure of the panel point at which the diagonal member 103 and the upper flange

101 are combined with each other in the conventional composite web truss girder. In the conventional connection structure of the panel point, a gusset plate 102 is installed at an end of the diagonal member 103, and stud bolts 104 are provided at the gusset plate 105. The stud bolt 104 is buried in concrete forming the upper flange 101 at the panel point.

[5] However, the use of stud bolt 104 in the above conventional connection structure of the panel point does not provide sufficient strength for preventing pullout. Especially, in the conventional connection structure of the panel point using the stud bolt 104, only a sum of inner forces of stud bolts 104 disposed in a group may be exerted. Since disposition interval of the stud bolts is narrow and stud bolts are concentratedly arranged, a shear fracture surface is formed at an upper end of the stud bolts when a pullout force and a shear force act, which is due to the fact that most of the stud bolts do not exert a pullout resistance because of a shear fracture surface. Thus, in the con- ventional structure, structural aspect different from a calculation resulted from a design occurs, and detailing is complex, so that the quality after concrete pouring is lowered and the constructability is deteriorated.

[6] Especially, a head is formed at an end of the stud bolt for a pullout resistance. The head of the stud bolt exerts its own function only when a pullout force is small in all of loads acting on concrete. In contrast, when a relatively high pullout force is generated to interact with other loads, such as at the panel point of a composite truss bridge, an effective resistance against the loads is impossible to be generated only with the head of the stud bolt.

[7] In addition, the gusset plate 105 is required, and since a lower end of the stud bolt

104 is separately welded to the gusset plate 105, installment work is very troublesome. Also, when many stud bolts 104 are welded in a small area, it is very difficult to weld the stud bolts 104 at precise positions.

[8] Also, the reinforcing bar 130 installed in the upper and lower flanges 101, 102 and the stud bolts 104 interfere with each other, so that there exists difficulty in arrangement of the reinforcing bar. Even when it is possible to insert the stud bolts 104 densely in to the space between the reinforcing bars 130, concrete may not be completely filled, and in order to prevent this problem, careful tamping is required, so that efficiency of work is lowered and construction period and construction cost are increased.

[9] In addition, when the stud bolt 104 is used, the reinforcement detailing of the reinforcing bar 130 installed in the upper and lower flanges 101, 102 becomes complex.

[10] When constructing a bridge, an angle of the diagonal member 103 may be required to be adjusted. In the above-mentioned conventional structure, since the gusset plate

105 is combined with and fixed to the end of the diagonal member 103, the angle of the diagonal member 103 is not easily adjusted as necessary.

[H]

Disclosure of Invention Technical Problem

[12] The present invention is devised to solve the problems of the prior art caused by using a gusset plate and stud bolts at a panel point at which a diagonal member and an upper flange or a lower flange are combined and thus, the present invention provides a new type of a connection structure of a panel point capable of having enough strength for prevention of pullout, simplifying reinforcement detailing of a reinforcing bar disposed at the upper and lower flanges, relieving troubles in working resulting from welding many stud bolts in a limited area, and securing ductile fracture by a resistance mechanism of a shear fracture surface, in which shear strength of concrete coexists with shear strength of the reinforcing bars disposed at a bent portion in a transverse direction and a direction perpendicular to the transverse direction, and a composite web truss girder having the connection structure.

[13]

Technical Solution

[14] In order to achieve the above object, there is provided a connection structure of a panel point of a composite web truss girder comprising an upper flange, a lower flange and a web having a truss structure of a diagonal member formed of steel, the diagonal member and the upper flange or the lower flange being combined at the panel point, wherein a cutoff portion is formed at an end of the diagonal member; wherein a T-type shear connector including a vertical plate and a horizontal plate horizontally installed on and joined with an upper end of the vertical plate is integrally installed with the diagonal member by inserting the vertical plate into the cutoff portion to be fixed to the cutoff portion; and the T-type shear connector is buried in concrete forming the upper flange or the lower flange to exert a shear resistance and a pullout resistance.

[15] In particular, a reinforcing bar is arranged at the upper and lower flanges; a throughhole is formed through the vertical plate of the T-type shear connector; and the reinforcing bar is disposed to penetrate the throughhole of the T-type shear connector.

[16] In addition, a coupling hole is formed through the end of the diagonal member corresponding to the throughhole formed through the vertical plate of the T-type shear connector and disposed inside the end of the diagonal member; and an engaging member passes through the coupling hole and the throughhole to reinforce coupling between the T-type shear connector and the diagonal member.

[17] In addition, the throughhole formed through the vertical plate of the T-type shear connector is formed larger than the end of the engaging member so that the engaging member may be shifted in a transverse direction inside the throughhole.

[18] In addition, an inner finish plate is respectively installed by a predetermined distance from a connection end of the diagonal member to close the end of the diagonal member, and concrete of the upper flange or the lower flange flows into the diagonal member to fill the diagonal member up to the inner finish plate, when the connection end of the diagonal member is buried in concrete forming the upper and lower flanges.

[19] Further, there is provided a composite web truss girder comprising an upper flange, a lower flange and a web having a truss structure of a diagonal member formed of steel, wherein a cutoff portion is formed at an end of the diagonal member and at a panel point, at which the diagonal member and the upper flange or the lower flange being combined; wherein a T-type shear connector including a vertical plate and a horizontal plate horizontally installed on and joined with an upper end of the vertical plate is integrally installed with the diagonal member by inserting the vertical plate into the cutoff portion to be fixed to the cutoff portion; and the T-type shear connector is buried in concrete forming the upper flange or the lower flange to exert a shear resistance and a pullout resistance.

[20] In addition, a reinforcing bar is arranged at the upper and lower flanges; wherein a throughhole is formed through the vertical plate of the T-type shear connector; and the reinforcing bar is disposed to penetrate the throughhole of the T-type shear connector.

[21] In addition, a coupling hole is formed through the end of the diagonal member corresponding to the throughhole formed through the vertical plate of the T-type shear connector and disposed inside the end of the diagonal member; and an engaging member passes through the coupling hole and the throughhole to reinforce coupling between the T-type shear connector and the diagonal member.

[22] In addition, the throughhole formed through the vertical plate of the T-type shear connector is formed larger than the end of the engaging member so that the engaging member may be shifted in a transverse direction inside the throughhole.

[23] In addition, an inner finish plate is respectively installed by a predetermined distance from a connection end of the diagonal member to close the end of the diagonal member, and concrete of the upper flange or the lower flange flows into the diagonal member to fill the diagonal member up to the inner finish plate, when the connection end of the diagonal member is buried in concrete forming the upper and lower flanges.

Advantageous Effects

[24] In the present invention, a vertical plate 21 of a T-type shear connector 20 is inserted into a cutoff portion 2 formed through an end of the diagonal member 1 without having a gusset plate, and the T-type shear connector 20 is buried in an upper flange or a lower flange of the panel point to have a shear connection. Thus, shear connection between the diagonal member 1 and an upper flange or a lower flange is much stronger and has further resistance to a pullout load, thereby preventing breakage due to the pullout load of the diagonal member at the point. In other words, the present invention improves a fracture strength due to the load at the panel point, and secures ductile fracture by a resistance mechanism of a shear fracture surface, in which shear strength of concrete coexists with shear strength of the reinforcing bars disposed at a bent portion in a transverse direction and a direction perpendicular to the transverse direction.

[25] Particularly, in the present invention, reinforcement detailing of a reinforcing bar disposed at the upper and lower flanges may be simplified, and troubles in working caused by welding stud bolts as a shear connector may be relieved.

[26] In addition, in the present invention, the reinforcing bar 130 arranged in the upper and lower flanges at the panel point may pass through the T-type shear connector 20. According to the above, the reinforcing bar 130 may also exert the pullout resistance, when a pullout force is generated. Thus, the pullout resistance is considerably increased and the ductile fracture may be induced, so that stability is improved. Particularly, there is an advantage that an effective resistance may be exerted even when a load acts repeatedly on the panel point or various loads such as a bending load, a tensile load and a shear load act simultaneously on the panel point.

[27] In the present invention, since the vertical plate 21 of the T-type shear connector 20 is inserted into the end of the diagonal member 1 without using the gusset plate, a protrusion height of the T-type shear connector 20 may be reduced at the panel point. Thus, a separate concrete haunch may not be required at the panel point, and construction may be simplified.

[28]

Brief Description of the Drawings

[29] FIG. 1 is a schematic perspective view illustrating a bridge using a conventional composite web truss girder.

[30] FIG. 2 is a schematic partial cross-sectional view illustrating the connection structure of the panel point at which the diagonal member and the upper flange are combined with each other in the conventional composite web truss girder.

[31] FIG. 3 is a schematic partial perspective view illustrating a feature that a T-type shear connector is attached to an end of the diagonal member so that the diagonal member is disposed to have a truss structure so as to manufacture the composite web truss girder of the present invention, in which a reinforcing bar for the upper and lower flanges is preassembled.

[32] FIG. 4 is a schematic perspective view illustrating assembly of the diagonal member of the composite web truss girder of the present invention.

[33] FIG. 5 is a schematic side view illustrating a composite web truss girder of the present invention.

[34] FIG. 6 is an enlarged view of a circular portion A in FIG. 5 so as to show a constitution of an exemplary embodiment of the present invention.

[35]

Best Mode for Carrying Out the Invention

[36] Although constitutions and features of the present invention have been described with reference to exemplary embodiments of the present invention, it is understood that the present invention should not be limited to these exemplary embodiments but various changes and modifications can be made within the spirit of the present invention.

[37] Hereinafter, a composite web truss girder and a connection structure thereof according to an exemplary embodiment of the present invention will be described with reference to the attached drawings.

[38] FIG. 3 is a schematic partial perspective view illustrating a feature that a T-type shear connector 20 is attached to an end of the diagonal member 1 so that the diagonal member is disposed to have a truss structure so as to manufacture the composite web truss girder according to the present invention, in which a reinforcing bar 130 for the upper and lower flanges is preassembled. FIG. 4 is a schematic perspective view illustrating assembly of the diagonal member 1 of the composite web truss girder. FIG. 5 is a schematic side view illustrating a composite web truss girder according to the present invention.

[39] As shown in the figures, in the present invention, the T-type shear connector 20 is disposed at an end of a diagonal member 1 and at a panel point at which diagonal members 1 at both sides, formed of steel and disposed obliquely, are combined with the upper and lower flanges. The T-type shear connector 20 includes a vertical plate 21, a horizontal plate 22 horizontally installed on and integrally formed with an upper end of the vertical plate 21. A throughhole 23 may be formed through the vertical plate 21.

[40] A cutoff portion 2 is formed through an end of the diagonal member 1. The vertical plate 21 of the T-type shear connector 20 is attached to the diagonal member 1 by welding the circumference of the cutoff portion 2 with the vertical plate 21 being inserted into the cutoff portion 2, so that the T-type shear connector 20 is joined with the diagonal member 1. In case that the throughhole 23 is formed through the vertical plate 21, as shown in the figures, a coupling hole 3 is formed through the end of the diagonal member 1 corresponding to the throughhole 23 disposed inside the end of the diagonal member 1, and an engaging member 4 such as a bolt is installed to pass through the coupling hole 3 and the throughhole 23, so that connection of the T-type shear connector 20 and the diagonal member 1 may be firmer.

[41] When the diagonal member 1 is connected to the upper and lower flanges formed of concrete at the panel point, the T-type shear connector 20 is buried in concrete of the upper and lower flanges. In this case, concrete flows into both sides of the T-type shear connector 20 through the throughhole 23 formed through the vertical plate 21 and then is cured. Thus, the T-type shear connector 20 and concrete of the upper and lower flanges are joined firmly. According to the above-described structure, the T- type shear connector 20 is buried in and integrally shear-connected to the upper and lower flanges. Thus, the web having a truss structure formed by the diagonal member 1 is combined with and joined with the upper and lower flanges.

[42] According to a structure having the T-type shear connector 20, a gusset plate installed at a conventional panel point is not used, and thus a structure is simplified. Sometimes, in constructing the composite web truss girder, the ends of a plurality of diagonal members 1 are connected in advance, and a web is formed to have a predetermined length in a unit type. Then, the web unit is moved to the field, and a plurality of web units is vertically assembled in the field to form a proper girder for an entire bridge. In the conventional panel point structure having the gusset plate, when the web units manufactured at a plant are moved to the field and connected to each other, the angle of the end of the diagonal member and the connection face of the gusset plate may not coincide with each other, and in this case, it is very difficult to connect the diagonal members to the gusset plate. However, since the present invention does not employ the gusset plate as described above, and the circumference of the cutoff portion 2 is welded with the vertical plate 21 of the T-type shear connector 20 being inserted into the cutoff portions 2 of the ends of the diagonal members 1 at both sides, the angle of the end of the diagonal member may be adjusted easily without difficulty in construction caused by the fact that the angle of the end of the diagonal member and the connection face of the gusset plate do not coincide with each other.

[43] Additionally, since the vertical plate 21 of the T-type shear connector 20 is inserted into the end of the diagonal member 1 without using the gusset plate, a protrusion height of the T-type shear connector 20 may be reduced at the panel point. Thus, a separate concrete haunch may not be required at the panel point, and construction may be simplified.

[44] In addition, sufficient strength for prevention of pullout may be obtained through the T-type shear connector 20, and thus arrangement detailing of the reinforcing bar 130 installed in the upper and lower flanges may be simplified.

[45] Especially, when the reinforcing bar 130 is arranged in the upper and lower flanges, although not shown in figures, the reinforcing bar 130 may pass through the throughhole 23 of the T-type shear connector 20. In this case, when a pullout force acts, the reinforcing bar 130 may exert pullout resistance. Thus, the pullout resistance is greatly increased, and ductile fracture may be induced, thereby enhancing stability. Particularly, effective resistance may be exerted while repeated load acts on the panel point, or various loads such as a bending load, a tensile load, a shear load, etc. act simultaneously on the panel point.

[46] The throughhole 23 of the T-type shear connector 20 through which the reinforcing bar 130 passes may be large to have sufficient looseness with the engaging member 4 being inserted thereinto. Thus, the engaging member 4 inserted through the throughhole 23 may move in a transverse direction within a predetermined range, so that the angle of the diagonal members 1 is adjusted for easier connection when the diagonal members 1 at both sides or the web unit are connected in the field. Also, the fact that the engaging member 4 may move in the throughhole 23 means that the connection end of the diagonal member 1 through which the engaging member 4 passes may move in the transverse direction by within a limited range with respect to the T-type shear connector 20 before the connection end is buried in concrete. Thus, although a stress concentration is generated at the connection ends of the diagonal members 1 when the web unit manufactured at a plant is moved to the field, the connection end of the diagonal member 1 may be free from risk of breakage.

[47] In addition, according to the above-described constitution, since the reinforcing bar

130 may be disposed easily, the T-type shear connector 20 may be easily inserted and installed to the complex arrangement structure of the reinforcing bar 130 disposed at the panel point, and concrete pouring may be performed easily despite the complex arrangement structure of the reinforcing bar 130, and conventional careful temping may not be required, thereby enhancing efficiency of work.

[48] According to another exemplary embodiment of the present invention, an inner finish plate 24 may be disposed at the connection end of the diagonal member 1 so that concrete may fill in the diagonal member 1 by a predetermined scope at the connection end of the diagonal member 1. FIG. 6 is an enlarged view of a circular portion A in FIG. 5 so as to show a constitution of another exemplary embodiment. In FIG. 6, the diagonal member 1 of the right-hand side is partially omitted for convenience s sake. As shown in FIG. 6, the inner finish plate 24 may be disposed in the diagonal member 1 to close a cross-section of the diagonal member 1. In the exemplary embodiment shown in FIG. 6, a catching member 25 is welded and attached to the inside of the diagonal member 1, and the inner finish plate 24 is caught by the catching member 25, thereby closing the cross-section of the diagonal member 1. However, installment method of the inner finish plate 24 is not limited thereto, and various methods such as direct welding of circumference of the inner finish plate 24 to an inner surface of the diagonal member 1 may be employed to install the inner finish plate 24.

[49] Thus, when the inner finish plate 24 is installed in the diagonal member 1 at the connection end of the diagonal member 1, and the connection end of the diagonal member 1 is buried in concrete to form the upper and lower flanges 101, 102, concrete to form the upper and lower flanges 101, 102 flows into the diagonal member 1 to fill the diagonal member 1 up to the inner finish plate 24. Thus, when concrete is filled from the connection end of the diagonal member 1 by a predetermined length, the connection end of the diagonal member 1 is reinforced to prevent the connection end of the diagonal member 1 from buckling.

[50] Industrial Applicability

[51] In the composite web truss girder of the present invention, a diagonal member and a buried typed T-type shear connector to shear-connect upper and lower portion of the diagonal member are used, so that a structural performance of a panel point may be enhanced without using a gusset plate.

[52]

Claims

[1] A connection structure of a panel point of a composite web truss girder comprising an upper flange, a lower flange and a web having a truss structure of a diagonal member (1) formed of steel, the diagonal member (1) and the upper flange or the lower flange being combined at the panel point, wherein a cutoff portion (2) is formed at an end of the diagonal member (1); wherein a T-type shear connector (20) including a vertical plate (21) and a horizontal plate (12) horizontally installed on and joined with an upper end of the vertical plate (21) is integrally installed with the diagonal member (1) by inserting the vertical plate (21) into the cutoff portion (2) to be fixed to the cutoff portion (2); and the T-type shear connector (20) is buried in concrete forming the upper flange or the lower flange to exert a shear resistance and a pullout resistance.

[2] The connection structure of claim 1, wherein a reinforcing bar (130) is arranged at the upper and lower flanges; a throughhole (23) is formed through the vertical plate (21) of the T-type shear connector (20); and the reinforcing bar (130) is disposed to penetrate the throughhole (23) of the T- type shear connector (20).

[3] The connection structure claim 2, wherein a coupling hole (3) is formed through the end of the diagonal member (1) corresponding to the throughhole (23) formed through the vertical plate (21) of the T-type shear connector (20) and disposed inside the end of the diagonal member (1); and an engaging member (4) passes through the coupling hole (3) and the throughhole (23) to reinforce coupling between the T-type shear connector (20) and the diagonal member (1).

[4] The connection structure of claim 3, wherein the throughhole (23) formed through the vertical plate (21) of the T-type shear connector (20) is formed larger than the end of the engaging member (4) so that the engaging member (4) may be shifted in a transverse direction inside the throughhole (23).

[5] The connection structure of any of claims 1 to 4, wherein an inner finish plate

(24) is respectively installed by a predetermined distance from a connection end of the diagonal member (1) to close the end of the diagonal member (1), and concrete of the upper flange or the lower flange flows into the diagonal member (1) to fill the diagonal member (1) up to the inner finish plate (24), when the connection end of the diagonal member (1) is buried in concrete forming the upper and lower flanges. [6] A composite web truss girder comprising an upper flange, a lower flange and a web having a truss structure of a diagonal member (1) formed of steel, wherein a cutoff portion (2) is formed at an end of the diagonal member (1) and at a panel point, at which the diagonal member (1) and the upper flange or the lower flange being combined; wherein a T-type shear connector (20) including a vertical plate (21) and a horizontal plate (12) horizontally installed on and joined with an upper end of the vertical plate (21) is integrally installed with the diagonal member (1) by inserting the vertical plate (21) into the cutoff portion (2) to be fixed to the cutoff portion (2); and the T-type shear connector (20) is buried in concrete forming the upper flange or the lower flange to exert a shear resistance and a pullout resistance.

[7] The composite web truss girder of claim 6, wherein a reinforcing bar (130) is arranged at the upper and lower flanges; wherein a throughhole (23) is formed through the vertical plate (21) of the T-type shear connector (20); and the reinforcing bar (130) is disposed to penetrate the throughhole (23) of the T- type shear connector (20).

[8] The composite web truss girder of claim 7, wherein a coupling hole (3) is formed through the end of the diagonal member (1) corresponding to the throughhole (23) formed through the vertical plate (21) of the T-type shear connector (20) and disposed inside the end of the diagonal member (1); and an engaging member (4) passes through the coupling hole (3) and the throughhole (23) to reinforce coupling between the T-type shear connector (20) and the diagonal member (1).

[9] The composite web truss girder of claim 8, wherein the throughhole (23) formed through the vertical plate (21) of the T-type shear connector (20) is formed larger than the end of the engaging member (4) so that the engaging member (4) may be shifted in a transverse direction inside the throughhole (23).

[10] The composite web truss girder of any of claims 6 to 9, wherein an inner finish plate (24) is respectively installed by a predetermined distance from a connection end of the diagonal member (1) to close the end of the diagonal member (1), and concrete of the upper flange or the lower flange flows into the diagonal member (1) to fill the diagonal member (1) up to the inner finish plate (24), when the connection end of the diagonal member (1) is buried in concrete forming the upper and lower flanges.