JP4572038B2 - Truss structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a truss structure mainly used as a bridge.
[0002]
[Prior art]
As this type of conventional truss structure, for example, a composite truss structure, a chord material that is a concrete member made of an upper chord material and a lower chord material, and a diagonal material that is a steel pipe member to which both end portions are joined. And a fixing means for fixing the diagonal member, which is the steel pipe member, to the string member.
[0003]
Here, as the fixing means, for example, a diagonal member as a steel pipe member is fixed to a gusset which is a steel material deeply embedded into a chord material which is a concrete member, or the end of the steel pipe member is expanded. For example, a PC steel bar fixed using a mortar is fixed by extending the free end of the steel bar into a chord material, which is a concrete member.
[0004]
[Problems to be solved by the invention]
However, in the truss structure of the type provided with the former fixing means, it is necessary to embed a gusset as an oblique material fixing steel material inside the chord material, which is a concrete member. Realizing easy construction becomes difficult. In addition, as a result, members having greatly different elastic coefficients are locally arranged, so that there may be a problem in terms of quality such as cracking.
[0005]
On the other hand, in the truss structure with the latter fixing means, once the diagonal member, which is a steel pipe member, is fixed to the chord member, which is a concrete member, it cannot be pulled out. Even if the material is damaged in some way, there is a problem that it can no longer be replaced.
In addition, in this type of truss structure, it is necessary to attach the diagonal member, which is a steel pipe member, prior to the concrete placement work for the chord member, which is a concrete member. There is also the problem of end up.
Here, as far as the diagonal material, which is a tensile material, in the truss structure of the type provided with the latter fixing means, there is a case where an opening occurs between the chord material, which is a concrete member, and the diagonal material, which is a steel pipe member. Yes, this results in a loss of the waterproof function, which may cause a problem in terms of durability.
[0006]
On the other hand, in the conventional truss structure, there is a difference in the axial force of the diagonal material depending on the application site in the bridge, and the cross section of the diagonal material varies depending on the application site. There are many. In addition, it is not desirable from the viewpoint of scenery that such diagonal materials are divided into sections and the cross-sections are not uniform.
[0007]
Therefore, the problem of the present invention is that it is possible to speed up and facilitate construction based on a simple structure, thereby ensuring high quality, and replacement of diagonal materials and a high degree of freedom based thereon. An object of the present invention is to provide a truss structure capable of carrying out the construction and improving the durability and adjusting the cross-sectional size of the diagonal material which is a tensile material.
[0008]
[Means for Solving the Problems]
That is, the truss structure according to the present invention includes a chord material composed of an upper chord material and a lower chord material, an oblique material joined at both ends thereof, and fixing the oblique material to the chord material that is a concrete member. The tension force is introduced so as to reduce the tensile stress that is to be generated in the diagonal member and is arranged along the axis of the diagonal member that is the tensile member while fixing both ends to the chord member. PC steel material.
[0011]
According to the truss structure of the present invention , in the truss structure having fixing means for fixing the diagonal material as the tensile material to the chord material as the concrete member, the PC steel material for reducing the tensile stress in the diagonal material as the tensile material is provided. Therefore, it is possible to speed up and facilitate construction based on a simple structure, thereby ensuring high quality, and exchanging diagonal materials and implementing construction with a high degree of freedom based on this. In addition to the diagonal material that is a tensile material, the diagonal material and the upper and lower chord materials can be integrated, resulting in improved durability and adjusting the cross-sectional size. It becomes possible to do.
[0012]
In such technical means, the “truss structure” is not limited to those made of string material and diagonal material, and may include vertical material and other members in addition to string material and diagonal material. Absent.
[0013]
Note that the upper chord material and the lower chord material are not limited to being in a parallel positional relationship.
[0014]
In addition, the “diagonal material” may be any material provided between the upper chord material and the lower chord material and having both end portions joined thereto, whether it is a concrete member or a steel pipe member. It doesn't matter.
[0015]
Furthermore, the “string material” is composed of an upper chord material and a lower chord material, and if at least one of them is a concrete member, it has a structural type or shape such as a beam member or a plate member. For example, a truss structure made of a composite member may be used.
[0016]
Furthermore, the term “fixing” here is provided integrally with the diagonal member so that the reinforcing bars, anchors and other members as the main members of the fixing means are embedded in the chord material which is a concrete member so as not to be pulled out. Means that.
[0017]
Here, as the “fixing means”, as long as it can fix the diagonal material to the chord material, which is a concrete member, the structure and type of the fixing material may be different. It doesn't matter.
[0018]
In addition, as an “anchor”, what kind of structure is used and what kind of material is used as long as it can fix the end plate to the string material with a certain fixing length. Whether or not.
[0019]
Therefore, it is not limited to, for example, an anchor, a reinforcing bar, or a PC steel material, and a stud, a convex cast steel, or the like can be appropriately selected and used.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0021]
1 is a side view showing an overall configuration of a truss structure according to an embodiment of the present invention, FIG. 2 is a side view showing a partial configuration of the truss structure, and FIG. 3 is a partial configuration of the truss structure in FIG. FIG. 4 is a cross-sectional view showing a partial configuration of the diagonal member in the truss structure.
[0022]
In the present embodiment, as shown in FIG. 1, the truss structure is a truss structure including a concrete floor slab 1 as a chord material that is a concrete member and an oblique member 2 that is a steel pipe member. PC steel stranded wire 4 as a steel material is provided.
That is, the truss structure in the present embodiment is a truss structure composed of a composite member not including a vertical member, in other words, a composite truss structure. Hereinafter, each component will be described in detail.
[0023]
(1) Concrete floor slab 1
As shown in FIG. 1, the concrete floor slab 1 is composed of a concrete upper floor slab 1a as an upper chord material and a concrete lower floor slab 1b as a lower chord material.
[0024]
The concrete upper floor slab 1a and the concrete lower floor slab 1b are substantially parallel to each other as shown in FIG.
The concrete upper floor slab 1a and the concrete lower floor slab 1b are both concrete members, more specifically, cast-in-place reinforced concrete as described above.
[0025]
As shown in the figure, the concrete floor slab 1 has a parallel portion 11 that occupies substantially the whole plate shape, and a protrusion that functions as a joint between the diagonal member 2 and the concrete floor slab 1 except for the parallel portion 11. Part 12.
As shown in the figure, the protruding portion 12 is a portion having a substantially triangular shape that is a side surface shape protruding from the parallel portion 11 toward the diagonal member 2 side.
Here, the reason why the protruding portion 12 has a substantially triangular shape is that a joining surface orthogonal to the axis of the diagonal member 2 is formed.
However, by forming the substantially triangular protrusion 12, it means that the shear resistance of the part is increased, and further, it is a desirable environment for waterproofing due to the situation where water cannot be accumulated in the part. There is also a secondary meaning that has been realized.
In addition, a notch for attaching a fixing device 41 for fixing the wire 4 made of PC steel is formed on the back side of the projecting part 12, but this notch is made of concrete by the necessity of rust prevention. Will be buried.
[0026]
(2) Diagonal material 2
As shown in the figure, the diagonal member 2 is provided between the concrete upper floor slab 1a and the concrete lower floor slab 1b, and both ends are joined to these.
That is, the upper end portion of the diagonal member 2 is joined to the concrete upper floor slab 1a, and the lower end portion of the diagonal member 2 is joined to the concrete lower floor slab 1b, as shown in FIG.
The oblique material 2 includes an oblique material (hereinafter referred to as “tensile oblique material”) 2a which is a tensile material and an oblique material (hereinafter referred to as “compressed oblique material”) 2b which is a compressed material.
In addition, from the viewpoint of rust prevention measures, a weather resistant steel plate was adopted as the diagonal member 2.
However, it is not restricted to this, For example, the method of heavy-corrosion-proofing to a normal steel plate etc. may be sufficient.
[0027]
(3) Fixing means 3
The fixing means 3 serves to fix the tensile diagonal material 2 a and the compression diagonal material 2 b to the concrete slab 1.
[0028]
As shown in FIG. 2, the fixing means 3 includes an end plate 21 fixed to the end of the tensile diagonal member 2 a and an anchor 22 that fixes the end plate 21 to the concrete floor slab 1.
[0029]
Here, as shown in FIG. 4, the fixing of the end plate 21 to the end of the tensile diagonal member 2a is used for the welding seam 21a by complete penetration welding with a groove angle of 45 °, and for the convenience of welding work. It consists of a backing metal 21b. The fixing of the end plate 21 is not limited to the welding method according to the present embodiment, and can be appropriately selected from other welding methods and joining methods.
[0030]
Further, as shown in FIG. 2, the anchor 22 includes an embedded nut 22 a embedded in the range of the protruding portion 12, a PC steel bar 22 b screwed into the embedded nut 22 a, and a PC steel after the concrete floor slab 1 is hardened. From a sheath 22c for securing a hollow area for mounting the rod 22b to the embedded nut 22a, and a fastening nut 22d for fastening the end plate 21 to the protruding portion 12 by a PC steel rod 22b screwed into the embedded nut 22a. It has become.
[0031]
Here, as shown in FIG. 3, the end plate 21 is provided with a fastening hole 22e which is a hole for fastening the PC steel rod 22b.
Thereby, even if the diagonal member 2 is damaged in some way during construction or after starting operation, the diagonal member 2 can be easily replaced. It is also possible to attach the diagonal member 2 after the construction of the concrete floor slab 1 is finished.
Although not shown in the figure, the portion of the PC steel bar 22b that is exposed to the outside is covered with a waterproof cap, thereby improving durability.
However, the method for improving the durability is not limited to this, and for example, a PC steel rod 22b having a rust-proof specification (for example, a product subjected to dacrotized treatment) may be used. Moreover, you may comprise only the part exposed to the exterior among PC steel bars 22b so that attachment or detachment is possible using a coupler.
[0032]
In the present embodiment, the non-shrink mortar 31 is placed between the protruding portion 12 and the end plate 21 in order to prevent a gap from being caused by unevenness (see FIG. 2). The non-shrinking mortar 31 is placed when the concrete 2 of the projecting portion 12 is placed after setting the diagonal member 2 according to the construction procedure. Absent.
[0033]
(4) PC steel strand 4
As shown in FIG. 1, the PC steel stranded wire 4 is disposed along the axis of the tensile diagonal member 2 a while fixing both ends to the concrete floor slab 1.
Here, the fixation of the PC steel strand 4 to the concrete floor slab 1 is realized by using the fixing device 41 at the notch portion on the back side of the protruding portion 12 for the concrete lower floor slab 1b as shown in FIG. It is supposed to be. On the other hand, the concrete upper floor slab 1a is not provided with a notch on the back side of the protruding portion 12 from the viewpoint of improving durability. Note that the notched portion of the concrete lower floor slab 1b is also backfilled with concrete, and durability is improved by ensuring rust prevention.
In addition, although the notch part for attaching the fixing device 41 which fixes the wire 4 from PC steel is formed in the back side of the protrusion part 12, this notch part will be different.
Further, specifically, the PC steel stranded wire 4 is arranged along the axis thereof inside the tensile diagonal member 2a as a steel pipe member, as shown in FIG. In addition, the PC steel strand 4 should just be arrange | positioned along the axis line of the tensile diagonal 2a, and is not limited to what is arrange | positioned inside the tensile diagonal 2a.
[0034]
Here, a tensile force is introduced into the PC steel strand 4 so as to reduce the tensile stress that should be generated in the tensile diagonal member 2a. Thereby, the anchoring length of the anchor 22 in the concrete floor slab 1 can be shortened. In the present embodiment, the design is such that no tensile force is generated between the protrusion 12 and the end plate 1.
In addition, the introduction of the tension force by the PC steel strand 4 prevents the mesh floor from being generated between the concrete floor slab 1 and the diagonal member 2, and it is possible to improve the waterproof effect and consequently the durability. .
[0035]
Next, the construction method of the truss structure according to the present embodiment will be described with reference to FIG.
[0036]
(1) Before start of construction (see Fig. 5 (a))
Now, the truss structure is in a state where the construction up to the previous day has been completed.
That is, the installation of the existing tensile diagonal member 2a and the existing concrete lower floor slab 1b is completed.
Further, the formwork support cart (not shown) is fixed at a position corresponding to the newly installed concrete upper floor slab 1a to be constructed next.
[0037]
(2) Construction of concrete upper slab 1a (see Fig. 5 (b))
In such a state, the new compression diagonal material 2b is installed as a temporary installation.
[0038]
And a formwork is installed in order to place concrete for the newly installed concrete upper floor slab 1a.
Subsequently, a new compression diagonal member 2b is installed as a main installation.
Next, the non-shrink mortar 31 is placed in the lower clearance area of the newly-compressed diagonal member 2b.
[0039]
Then, as for the new concrete upper floor slab 1a, rebar assembly is performed, and a part of the anchor 22 for fixing the tensile diagonal member 2a to be constructed next is installed.
[0040]
And about the new concrete upper floor slab 1a, while concrete placement is performed, the curing period is taken after placement.
After the curing period, a tension force is introduced to the PC steel rod 22b with respect to the anchor 22 for fixing the new compression slant 2b.
Subsequently, tension is introduced to the wire 4 from the PC steel.
[0041]
Thereby, the construction of the new concrete upper floor slab 1a is completed.
In addition, a formwork support trolley | bogie moves to the position corresponding to the concrete lower floor slab 1b which should be constructed next, and will be in a fixed state.
[0042]
(3) Construction of concrete floor slab 1b (see Fig. 5 (c))
In such a state, the newly installed tensile diagonal member 2a is installed as a temporary installation. At this time, the strand 4 of PC steel is inserted inside the newly installed tensile diagonal 2a.
[0043]
And a formwork is installed in order to place concrete for the newly installed concrete lower floor slab 1b.
Subsequently, the newly installed tensile diagonal member 2a is installed as a permanent installation.
Next, the non-shrink mortar 31 is placed in the upper region of the newly installed tensile diagonal 2a.
[0044]
Then, as for the newly installed concrete lower floor slab 1b, rebar assembly is performed, and a part of the anchor 22 for fixing the compression diagonal material 2b to be constructed next is installed.
[0045]
And about concrete newly placed floor slab 1b, while placing concrete, a curing period is taken after placement.
After the curing period, a tension force is temporarily introduced into the PC steel rod 22b for the anchor 22 for fixing the newly installed tensile diagonal member 2a.
Subsequently, tension is introduced into the wire 4 from the PC steel. This makes it possible to reduce the tensile stress that should occur in the tensile diagonal material 2a.
Next, a tension force is permanently introduced into the PC steel rod 22b for the anchor 22 for fixing the newly installed tensile diagonal member 2a.
[0046]
Thereby, the construction of the new concrete lower floor slab 1b is completed.
In addition, a formwork support trolley | bogie moves to the position corresponding to the concrete lower floor slab 1b which should be constructed next, and will be in a fixed state.
[0047]
Therefore, according to the truss structure according to the present embodiment, since the diagonal member 2, which is a steel pipe member, is provided with the fixing means 3 for fixing to the concrete floor slab via the end plate 21 and the anchor 22, it is based on a simple structure. It is possible to speed up and facilitate the construction, and as a result, it is possible to guarantee high quality, and it is possible to replace the diagonal member 2 and to carry out construction with a high degree of freedom based on this. It becomes possible.
[0048]
In addition, since the PC steel strand 4 for reducing the tensile stress in the tensile diagonal member 2a is provided, it is possible to improve the durability and adjust the size of the cross section, particularly for the tensile diagonal member 2a.
[0049]
【The invention's effect】
According to the truss structure according to the present invention, since it is configured as described above, it is possible to speed up and facilitate construction based on a simple structure, thereby ensuring high quality, It is possible to carry out the replacement and construction with a high degree of freedom based on this, and for the diagonal material which is a tensile material, the durability can be improved and the size of the cross section can be adjusted.
[Brief description of the drawings]
FIG. 1 is a side view showing an overall configuration of a truss structure according to an embodiment of the present invention.
FIG. 2 is a side view showing a partial configuration of a truss structure according to an embodiment of the present invention, and FIG. 3 shows a partial configuration of the truss structure.
3 is a view in the direction of arrow A in FIG. 2 showing a partial configuration of the truss structure according to the embodiment of the present invention.
FIG. 4 is a cross-sectional view showing a partial configuration of a diagonal member in a truss structure according to an embodiment of the present invention.
FIG. 5 is a construction diagram illustrating a method for constructing a truss structure according to an embodiment of the present invention.
[Explanation of symbols]
1 ... Concrete floor slab (string material)
1a: Concrete upper floor slab (upper chord material)
1b: Concrete lower floor slab (lower chord material)
2 ... diagonal material 2a ... tensile diagonal material (diagonal material which is tensile material)
2b ... Compressed diagonal material (an oblique material which is a compressed material)
3 ... Fixing means 4 ... PC steel strand (PC steel)
DESCRIPTION OF SYMBOLS 11 ... Parallel part 12 ... Protruding part 21 ... End plate 21a ... Welding seam 21b ... Backing metal 22 ... Anchor 22a ... Embedded nut 22b ... PC steel rod 22c ... Sheath 22d ... Fastening nut 22e ... Fastening hole 31 ... No contraction Mortar 41. Fixing device

Claims (1)

  A chord material composed of an upper chord material and a lower chord material, a diagonal material joined to both ends thereof, a fixing means for fixing the diagonal material to the chord material, which is a concrete member, and both end portions of the chord material A PC steel material that is disposed along the axis of the diagonal material that is a tensile material while being fixed, and into which a tensile force is introduced so that a tensile stress that should be generated in the diagonal material is reduced. Truss structure.

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