JP4572028B2 - Steel-concrete composite truss joint structure and steel-concrete composite truss erection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a joint structure of a steel-concrete composite truss composed of a concrete upper and lower chord material and a steel diagonal material, and a method for installing a steel-concrete composite truss.
[0002]
[Prior art]
A steel-concrete composite girder formed by connecting parts (webs, etc.) that connect concrete upper and lower chords (for example, concrete slabs) to each other using steel, because light and strong steel is used to connect upper and lower chords. It is economical and has an excellent structure. As such a steel-concrete composite structure, in addition to a composite structure in which the web is connected with corrugated steel sheets and other steel materials, a steel-concrete composite truss in which the concrete upper and lower floor slabs are connected with steel pipe diagonals is used for long bridges. It is considered to be a more economical structure than the web.
[0003]
In such a steel-concrete composite truss structure, the force must be transmitted smoothly at the joint between the concrete member and the steel member, and the generation of large local stress must be suppressed so that it does not become a structural weak point. . In the steel-concrete composite truss structure, it is desirable to employ a structure in which each of the steel diagonal members is directly joined to the concrete upper or lower floor slab. For example, in the conventional joining structure shown in FIG. 10, a steel plate 102 is welded to an end portion of a steel member 101 that is an oblique material at a substantially right angle to the axis of this member, and a plurality of stud gibbles 103 are erected from this steel plate. . Then, concrete is placed so as to embed the stud gibber 103 to form a concrete member 104 joined integrally with the steel member 101. Further, in the joining structure shown in FIG. 11, the steel plate 112 is welded to the end of the steel member 111 in the same manner as in the example shown in FIG. 10, and a PC steel rod or a steel bar is inserted into the screw hole drilled in the steel plate 112. The rod-shaped steel material 113 is screwed together. And the concrete member 114 and the steel member 111 are integrated by embedding this PC steel bar or steel bar in concrete.
[0004]
In the structure as shown in FIG. 10, the force acting on the steel member 101 is transmitted to the concrete member 104 through the steel plate 102 at the end and the stud gibel 103 welded to the steel plate 102. For this reason, the welded portion between the steel member 101 and the steel plate 102 and the welded portion between the steel plate 102 and the stud gibber 103 are required to have sufficient strength and reliability, and it is necessary to strictly manage and inspect the welding process. Moreover, it is difficult to use a high-strength steel material for the stud gibber 103 to be welded, and there are cases where the number of necessary stud gibels increases and the arrangement becomes difficult. Furthermore, in a steel-concrete composite truss bridge or the like, a force that repeatedly fluctuates acts on the joint portion between the concrete member and the steel member, and the weld joint portion between the steel member 101 and the steel plate 102 and the base portion of the stud divel 103 are subject to fatigue failure. There is a problem that causes.
[0005]
In the structure shown in FIG. 11, high strength steel such as a PC steel bar can be used as the rod-shaped steel material 113, and the number of the rod-shaped steel materials 113 can be reduced to simplify the structure of the joint portion. When the rod-shaped steel material 113 is provided with a thread, and a large axial force or bending moment is repeatedly applied to the joint portion between the concrete member 114 and the steel member 111, the rod-shaped steel material 113 is fatigued at the portion where the thread is provided. There is a risk of destruction. Further, similarly to the structure shown in FIG. 10, there is a possibility that fatigue failure may occur at the welded joint between the steel member 111 and the steel plate 112.
[0006]
On the other hand, as shown in FIG. 6, a technique is provided in which a bevel 132 is provided at the end of the diagonal member 131, a protrusion 135 is formed on the upper and lower chord members 134, and the end of the diagonal 131 is embedded in the protrusion 135 There is. This technique is not preferable because the protrusion 135 becomes large. The technique shown in FIG. 7 is a type in which a gusset plate 143 is attached to the end portion of the diagonal member 141, a large number of dowels 145 are provided on the gusset plate 143, and the dowels 145 are embedded in the upper and lower chord members 144. This technique also has the same problem as in FIG.
[0007]
Further, as an improved technique, a technique as shown in FIG. 8 is disclosed in Japanese Patent Laid-Open No. 2000-17731. In this technique, a part of the rod-shaped steel material 152 is inserted into the steel tube member 151 from the end of the steel tube member 151, and a protrusion is formed on the inner surface of the portion of the steel tube member 151 where the rod-shaped steel material 152 is inserted. The inside of the vicinity of the end portion of the member 151 wraps the rod-shaped steel material 152 and is filled with a filler that hardens and adheres to the rod-shaped steel material 152 and the steel pipe member 151 so that the end portion of the steel pipe member 151 is abutted against the concrete. A concrete member 154 is formed, and the portion protruding from the end of the steel pipe member 151 of the rod-shaped steel material 152 is a joint structure between the concrete member 154 and the steel pipe member 151 embedded in the concrete member 154.
[0008]
In this technique, force is transmitted from the filler 153 by the adhesive force distributed and acting over a wide range of the circumferential surface of the rod-shaped steel material 152, stress concentration does not occur in the rod-shaped steel material 152, and fatigue resistance is improved. Moreover, the adhesiveness between the steel pipe member 151 and the filler 153 is strengthened by the plurality of protrusions provided on the inner surface of the steel pipe member 151. On the other hand, even when the adhesiveness between the filler 153 and the rod-shaped steel 152 and the filler 153 and the steel pipe member 151 is impaired, the steel plate material 155 locked to the rod-shaped steel 152 and the end welded to the steel pipe member 151 are joined. The relative displacement between the consolidated body of the filler 153 and the rod-shaped steel material 152, or the consolidated body of the filler 153 and the steel pipe member 151 is restrained by the partial steel plate 156, and the tensile force acting on the steel pipe member 151 is ensured. It is transmitted to the rod-shaped steel material 152. For this reason, the joining portion has double safety, and has a structure excellent in reliability and durability. However, this technique has a problem that the structure is complicated, there are many parts, and construction is difficult.
[0009]
As another technique, Japanese Patent No. 2971044 discloses a truss bridge in which the upper chord material and the lower chord material are made of prestressed concrete and the diagonal material is made of steel as shown in FIG. Are connected to each other through a universal joint 163, and the universal joint 163 is embedded in the concrete 164 so that the diagonal members 161 and 162 are connected to the upper chord member or the lower chord member. Is disclosed. In this technique, the angle formed by the adjacent diagonal members 161 and 162 can be easily adjusted by the universal joint 163, and the end of the diagonal members 161 and 162 can be obtained by hitting the concrete 164 after adjusting the angle. And the upper chord member or the lower chord member 165 can be connected. Moreover, the prestress is introduced into the upper chord material and the lower chord material after the concrete is hardened.
[0010]
For example, in the case of construction by the overhanging construction method, construction is performed so that a bridge girder is projected for each block of a predetermined length, but the angle formed by the adjacent diagonal members 161 and 162 can be easily set by the universal joint 163. Since it can be adjusted, it can be applied while correcting the position of the overhanging block so that it always matches the target. Therefore, there is an advantage that the construction can be performed with high accuracy, and the concrete construction management can be performed by a normal simple construction management. In addition, since the end portions of the universal joint 163 and the diagonal members 161 and 162 are fixed in a state compressed with prestressed concrete, the diagonal members 161 and 162 and the upper chord member or the lower chord member 165 are firmly connected. be able to. Further, since the universal joint 163 is only embedded in the upper chord member or the lower chord member 165 together with the end portion of the oblique member, the case where the oblique members 161 and 162 are connected to the upper chord member or the lower chord member 165 is connected. The point structure does not become large. Moreover, since the diagonal material is made of steel, the weight can be reduced. Furthermore, since the upper chord material and the lower chord material are made of prestressed concrete, the construction management is simple, and the weight can be reduced, the cost can be reduced. Moreover, it is described that the reduction in weight is advantageous in improving the earthquake resistance.
[0011]
[Problems to be solved by the invention]
The steel-concrete composite truss structure is a preferable structure because it can reduce its own weight and lengthen the span as compared with a conventional concrete bridge. In this composite truss structure, the joint is an important part in the structure where the concrete floor slab and steel diagonal are integrated and the cross-sectional force must be sufficiently transmitted. For this reason, several types of grading structures have been developed so far, but there is currently no definitive state.
[0012]
The technology related to the steel-concrete composite truss structure shown in FIGS. 7, 8, and 9 is an improvement on the conventional steel-concrete composite truss joint, which has excellent characteristics, fatigue testing and load bearing capacity. As a result of the tests, it has been confirmed that there is no practical problem in terms of strength ("Fatigue test of steel-concrete composite truss joint" Prestressed Concrete Technology Association 8th Symposium Proceedings: 1998 October). However, these scoring structures have a problem in appearance or are complicated in structure and have many parts and are expensive. That is,
(1) Regarding the technique shown in FIG. 7, the method of combining the steel plate and the stud is not good in appearance because all the graded structures are installed outside the floor slab. (2) In the technique shown in FIG. (3) The technology shown in FIG. 9 is made of a casting that uses an expensive mold, so a new mold is used each time the diagonal angle changes. The current situation is that the structure is not decisive and each has its advantages and disadvantages.
[0013]
The grading structure of the present invention has few types of components, is easy to manufacture and construct, and aims to provide a rational grading structure for a steel-concrete composite truss that will be adopted in earnest in the future. To do.
[0014]
The present invention also provides an erection method capable of easily and efficiently constructing a truss having a truss joint structure according to the present invention when an appropriate steel-concrete composite truss is constructed as a long span bridge body. For the purpose.
[0015]
[Means for Solving the Problems]
The present invention provides a grading structure that uses a gusset plate and a stud gibel only, which is the original concept of a truss, with a grading point as a pin structure. That is, according to the present invention, in the steel-concrete composite truss, the diagonal member is a square steel pipe, the tensile member is provided with pin coupling portions at both ends, and the compression member is embedded in the upper and lower chord material concrete at both ends. A steel-concrete composite truss joint structure comprising a pair of stud gusseted gusset plates and a pin insertion hole for insertion into the pin coupling portion.
[0016]
In constructing a truss having a steel-concrete composite truss joint structure according to the present invention, the method of the present invention is configured to pin-connect diagonal members to be connected, and to connect intermediate portions between the adjacent diagonal members temporarily connected to each other. Assemble the diagonal members that are connected and connected to each other in the installation posture, attach the assembled diagonal members to the end of the existing truss, and overhang and install the upper and lower chord concrete sequentially on the overhanging part to extend the truss It is the construction method of the steel concrete composite truss characterized by doing. In other words, two to three pins are connected to the diagonal from the existing diagonal, and the middle part of each diagonal is connected with an extendable binder to hold it in place, and concrete is placed in sequence. Extend the truss. Thus, the steel-concrete composite truss having the joint structure of the steel-concrete composite truss of the present invention can be installed smoothly.
[0017]
Of course, with a short-span composite truss, the entire bridge body can be manufactured off-line and installed in a conventional manner.
[0018]
The features of the joint structure of the steel-concrete composite truss and the construction method of the steel-concrete composite truss of the present invention are as follows.
[0019]
(A) The diagonal member (square steel pipe) on the pulling side has a simple structure in which a pin is cut to a predetermined length, a hole through which a pin is passed, and a reinforcing plate is attached around the hole.
[0020]
(B) Diagonal material on the compression side (using a square steel pipe as in the tension side) is a structure that can be completed by simply attaching the steel plate with the stud gibber on the end to both sides by factory welding. The structure is easy to manufacture.
[0021]
(C) Assembling in the field has a structure that allows easy joining by simply inserting the steel pipe on the tension side into the two gusset plates on the compression side and inserting the pins.
[0022]
(D) The axial force from each diagonal member is transmitted to the floor slab concrete by the stud gibber (installed so as to be planted by welding) on the gusset plate, but in this structure, the stud part is completely the floor slab. Since it is within the thickness of the concrete, the transmission of force is smooth, and the structure has the same strength as the conventional one.
[0023]
(E) Since there are three types of parts that make up the rating: pins, gusset plates, and stud gibbels, it is not only easy to manufacture but also low in construction costs and simple on-site construction. Moreover, it can be said that it is an epoch-making grading structure that can contribute to shortening of the process.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0025]
FIG. 3 is a side view schematically showing a steel-concrete composite truss, and FIG. 4 is a front view thereof. The upper chord member 10 and the lower chord member 20 are, for example, prestressed concrete upper and lower floor slabs, and diagonal members 30, 31, and 41 (the diagonal member 31 is a compression-side diagonal member and the diagonal member 41 is a tensile-side diagonal member). Is a steel material such as a square steel pipe. The joint portion between the upper and lower chord members 10, 20 and the diagonal members 30, 31, 41 of such a steel-concrete composite truss is a rating 43. Conventionally, the structure of the rating point 43 is a gibber, a steel bar, a special hardware or the like as shown in FIGS. 6 to 11, but in the present invention, a pin connection is used as shown in FIGS.
[0026]
FIG. 1 shows a scoring structure according to an embodiment of the present invention, and shows a connecting portion with a lower chord member 20. The lower chord material 20 is the same as the upper chord material 10. FIG. 2 is a front view of the diagonal member 31. A gusset plate 32 is attached to the end of the diagonal member 31 on the compression side made of a square steel pipe, and a large number of stud gibbles 33 are welded to the gusset plate 32 and are embedded in the concrete of the lower chord member 20 to be gusseted. The plate and the lower chord material 20 are integrated. And the pin hole 34 is provided in the connection part with the diagonal material 41 of the tension | pulling side. A portion of the pin hole 34 into which the pin 42 is inserted is reinforced by a reinforcing plate 36. The hole 35 is an inspection hole.
[0027]
The diagonal member 41 on the tension side is provided with a pin hole for inserting a pin 42 at the tip, and the diagonal member 31, 41 is joined by inserting the pin 42 so as to coincide with the pin hole 34 on the compression side.
[0028]
Next, with reference to FIG. 5, the construction method of the steel concrete composite truss of this invention is demonstrated. An overhanging work device 60 is fixed on an already-worked steel-concrete composite truss in which the upper chord member 10, the lower chord member 20, and the diagonal members 31 and 41 are assembled, with its tip projecting forward. The overhanging work device 60 suspends a frame receiving base 62 and a scaffold 63 for forming upper and lower chord members (upper and lower floor slabs) 10 and 20 from the beam 61. The overhanging work device 60 builds the upper and lower chord members (upper and lower floor slabs) 10 and 20 by the same work procedure as that of a conventional prestressed concrete bridge cast-in-place.
[0029]
In the construction of the steel-concrete composite truss having the joint structure according to the present invention, prior to the construction of the upper and lower chord members (upper and lower floor slabs) 10 and 20, the connecting diagonal members 31 and 41 are projected forward and assembled. For this reason, a truss erection trolley 66 is provided that suspends diagonal material on the beam 61 of the overhanging work device 60 and conveys it diagonally. A plurality of diagonal members 31, 41 are pin-bonded at their joints, and the diagonal members are assembled in the installation posture by the truss erection jigs 51, 52, and this combination is conveyed forward by the truss erection trolley 66. And attach it to the tip of the existing steel-concrete composite truss. The truss erection jigs 51 and 52 have a structure that can be expanded and contracted by a turnbuckle method or the like, and can adjust the assembly posture such as the direction and height of the diagonal members. The diagonal members 31, 41 are provided with mounting seats for attaching the truss erection jigs 51, 52 in advance. The upper and lower chord members (upper and lower floor slabs) 11 and 21 are sequentially constructed in a state where the diagonal members 31 and 41 are overhanging.
[0030]
By repeating the above, a long-span steel-concrete composite truss having the joint structure of the present invention can be easily constructed.
[0031]
【The invention's effect】
According to the present invention, in the steel-concrete composite truss, the grade structure is a reasonable grade structure for a steel-concrete composite truss, since the number of types of components is small, and manufacturing and construction are easy.
[Brief description of the drawings]
FIG. 1 is a diagram showing a scoring structure according to an embodiment of the present invention.
FIG. 2 is a front view of a diagonal member.
FIG. 3 is a side view schematically showing a steel-concrete composite truss.
4 is a front view of FIG. 3;
FIG. 5 is an explanatory diagram of the method of the present invention.
FIG. 6 is an explanatory diagram of a conventional technique.
FIG. 7 is an explanatory diagram of a conventional technique.
FIG. 8 is an explanatory diagram of the prior art.
FIG. 9 is an explanatory diagram of a prior art.
FIG. 10 is an explanatory diagram of the prior art.
FIG. 11 is an explanatory diagram of a conventional technique.
[Explanation of symbols]
10 Upper chord material 20 Lower chord material 11, 21 Upper and lower chord materials (upper and lower floor slabs)
30, 31, 41 Diagonal material 32 Gusset plate 33 Givel 34 Pin hole 35 Hole 36 Reinforcement plate 42 Pin 43 Rating point 51, 52 Truss installation jig 60 Overhang work device 61 Beam 62 Formwork base 63 Scaffolding 66 Truss Trolley with shelf

Claims (2)

In a steel-concrete composite truss, the diagonal material is a square steel pipe, the diagonal material on the tension side has pin joints on both ends, and the diagonal material on the compression side is a pair of gussets with studs that are embedded in the upper and lower chord material concrete. A steel-concrete composite truss joint structure, comprising a plate, wherein the gusset plate is provided with a pin insertion hole to be inserted into the pin coupling portion. In constructing a truss having a steel-concrete composite truss joint structure according to claim 1, the diagonal members to be connected are connected by pins, and the intermediate portions of the adjacent adjacent diagonal members are connected by a temporary connecting material. The steel is characterized by assembling the materials in the installation posture, attaching the assembled diagonal members to the end of the existing truss, and overhanging them in sequence, and then extending the truss by placing the upper and lower chord concrete sequentially on the overhanging parts. Construction method of concrete composite truss.

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