JP2007239270A - Pc box girder bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate labor such as maintenance control, by easily securing quality of a joining structure, by rationalizing by applying an improvement to the joining structure with a concrete lower floorboard of a PC box girder bridge using a corrugated steel plate web. <P>SOLUTION: This PC box girder bridge is formed as a structure that a lower flange 11 is installed on the lower end of the corrugated steel plate web 10; a large number of steel plates 12 are fixed in a vertical attitude to a side surface of the corrugated steel plate web 10 and an upper surface of the lower flange 11; and are engaged with the steel plates 12 by inserting bar steel 14 in the bridge axis direction into a through-hole 13 of the steel plates 12; and these plates are built in the concrete lower floorboard 40. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a PC box girder bridge, and more particularly to a novel joint structure between a corrugated steel sheet web and a concrete lower floor slab in a PC box girder bridge using a corrugated steel sheet web.

  Corrugated steel web bridges, in which concrete webs are replaced with corrugated steel plates in PC bridges, are not only reduced in main girder weight, but also because of the accordion effect and high shear buckling properties associated with the web steel shape characteristics. It is a composite structure of steel and concrete that is excellent in economic efficiency and workability, such as excellent stress introduction efficiency and omission of stiffeners.

  Usually, as a joining structure of the corrugated steel web and the concrete lower floor slab, a structure in which the lower end of the corrugated steel web is directly embedded in the concrete, or a mechanical joint such as a stud gibber on the lower surface of the steel flange attached to the lower end of the corrugated steel web. Structures are used. (For example, refer nonpatent literatures 1 and 2.).

  In such a structure, it is necessary to provide scaffolding equipment and formwork equipment outside the corrugated steel web when constructing the concrete lower floor slab in the PC box girder bridge constructed on site.

  In the case of a joint structure in which a mechanical joint such as a stud diver is provided on the lower surface of the steel flange and the lower floor concrete is engaged with the stud diver, the concrete is filled under the steel flange. It will be a hit. Therefore, careful attention is required in construction so as not to cause defects in the concrete.

  In the above joint structure, the boundary point between the concrete lower floor slab and the corrugated steel web is located outside the main girder. A separate scaffolding is required for maintenance.

  In order to avoid concrete backlash on the lower surface of the steel flange as described above and to maintain and manage the steel / concrete joint, there is an example of a cross-sectional shape in which a concrete bottom slab is placed on the upper surface of the steel flange. (For example, refer nonpatent literature 3.).

In this case, for the joining of the corrugated steel web and the concrete lower floor slab, a connecting structure by a large number of horizontal horizontal stud studs attached to the corrugated steel web has been adopted. However, in this case, a large number of horizontal stud gibbles are required, and there are problems such as complicated rebar assembly of this portion and difficulty in compaction when placing concrete.
Prestressed Concrete Technology Association: "The 7th Symposium Proceedings" October 1977, p747-752 Prestressed Concrete Technology Association: “Prestressed Concrete” vol. 37, no. 2, Mar. 1995 p69-78 Prestressed Concrete Technology Association: “Prestressed Concrete” vol. 44, no. 1, Jan. 2002 p56

  In a PC box girder bridge using corrugated steel webs, a cross-sectional shape with a lower floor slab placed on the steel flange in consideration of the maintainability of the steel-concrete joint, avoiding concrete backlash on the lower surface of the steel flange In the conventional example, a large number of stud studs in the horizontal direction are required, the rebar assembly becomes complicated, and it is difficult to compact the concrete when placing it.

  The present invention solves the above problems, rationally and simplifies the joint structure of the PC box girder bridge using the corrugated steel web with the concrete lower floor board, facilitates ensuring the quality of the joint structure, maintenance inspection, etc. The purpose is to provide a PC box girder bridge that eliminates the hassle of.

  The present invention has been made to solve the above problems, and is a PC box girder bridge characterized by taking the following technical means. That is, according to a first aspect of the present invention, in a PC box girder bridge using a corrugated steel web, a plurality of steels having a flange at the lower end of the corrugated steel web and having through holes on the upper surface of the flange and the side of the corrugated steel web. A concrete lower floor slab in which a plate is fixed in a posture in which the steel plate surface is vertical, a long steel bar is locked to the steel plate through the through-hole, and the steel plate and the long steel bar are built in. It is attached to the upper surface of the flange.

  Further, according to a second aspect of the present invention, in a PC box girder bridge using a corrugated steel web, a long strip steel plate having a flange at the lower end of the corrugated steel web and having a plurality of through holes is provided on the upper surface of the flange. A plurality of reinforcing bars that are erected and fixed along the bridge axis direction and that intersect with the strip steel plate through the through hole are disposed, and a stud that is in contact with the lower floor slab side surface of the corrugated steel sheet web and the upper surface of the flange A concrete lower floor slab is provided on the upper surface of the flange. The concrete lower floor slab includes a gibber and incorporates the strip steel plate, the multiple rebars, and the stud gibber.

  Further, according to a third aspect of the present invention, in a PC box girder bridge using a corrugated steel web, a flange is provided at the lower end of the corrugated steel web, and a long steel bar is provided along the bridge axis direction on the side of the corrugated steel web above the flange. The concrete lower floor slab is fixed on the side of the corrugated steel sheet web and is in contact with the lower floor slab of the corrugated steel sheet web, and the long steel bar and the stud gibber are incorporated in the upper surface of the flange. To do.

  1st-3rd invention of this invention is related with the joining structure of the corrugated steel plate web of a PC box girder bridge using a corrugated steel web, and a concrete lower floor slab, and the problem to be solved in an industrial field. Are the same.

  The PC box girder bridge of the present invention improves the manufacturability of steel members, the workability in rebar assembly of lower floor slabs, and the workability of compaction in concrete placement by simplifying the joining structure. Can be easily secured, and the reliability is increased, and the maintenance work is reduced.

  Embodiments of the present invention will be described below with reference to the drawings. First, the prior art will be described. FIG. 4 is a front view of a PC box girder bridge 1 using a conventional corrugated steel web, and is composed of a corrugated steel web 10, a concrete lower floor slab 40, and a concrete upper floor slab 50. The joint (A part) between the corrugated steel web 10 and the concrete lower floor slab 40 is a structure in which the corrugated steel is directly embedded in the concrete (FIG. 5), or a stud gibber on the lower surface of the steel flange disposed below the corrugated steel web. Such a mechanical joint structure (FIG. 6) or the like is used.

  In the structure shown in FIG. 5, a large number of through holes 61 are formed in the vicinity of the lower end of the corrugated steel sheet web 10, and a large number of through reinforcing bars 62 intersecting the corrugated steel sheet web 10 are inserted through the through holes 61. A long joining bar 63 that is mechanically engaged with the penetration reinforcing bar 62 is arranged in the bridge axis direction, and the vicinity of the lower ends of the penetration reinforcing bar 62, the joining bar 63, and the corrugated steel sheet web 10 is in the concrete lower slab. It is a structure in which a concrete lower floor slab is constructed so as to be built in. In this case, it is necessary to provide scaffolding equipment and formwork equipment on the outside of the corrugated steel web 10 when the concrete lower floor slab is constructed.

  FIG. 6 shows the latter structure. As shown in FIG. 6, in the case of a joined structure in which a steel flange 11 is provided at the lower end of the corrugated steel web 10 and a gibber is provided on the lower surface thereof, the concrete is required due to the necessity of filling the concrete below the steel flange 11. Counterstrokes. Accordingly, there is a risk that defects or the like may occur in the construction of the concrete lower floor slab 40.

  5 and 6, since the boundary point between the concrete lower floor slab 40 and the corrugated steel web 10 is outside the main girder, rainwater or the like accumulates here, which tends to be a weak point in durability. For this reason, it is necessary to pay attention during maintenance such as inspection, and in that case, there is a problem that a separate scaffold or the like is required.

  7, FIG. 8 (a) and FIG. 8 (b) show a conventional example in which this is improved. The PC box girder bridge 1 shown in FIG. 7 has a structure in which the corrugated steel sheet web 10, the concrete lower floor slab 40, and the joint structure (part B) are constructed with the concrete lower floor slab 40 on the steel flange 11. .

  FIG. 8A is a front view thereof, and FIG. 8B is a view taken along the line CC of FIG. 8A.

  As shown in FIGS. 8 (a) and 8 (b), in the joining structure of the corrugated steel web 10 and the concrete lower floor slab 40, a number of stud dowels arranged on the surfaces of the corrugated steel web 10 and the steel flange 11 are used. The joint structure by was adopted. In this case, it is necessary to provide the corrugated steel sheet web 10 with a large number of horizontal stud gibbles, and the rebar assembly of the concrete lower floor slab in this part becomes complicated, and compaction at the time of placing the concrete becomes difficult. .

  Next, an embodiment of the present invention in which the above prior art is improved will be described with reference to the drawings.

  1 (a) and 1 (b) show a joining structure of a corrugated steel sheet web 10 and a concrete lower floor slab 40 according to the first embodiment of the present invention. FIG. 1 (a) is a front view. (AA arrow view of FIG. 1B), FIG. 1B is a plan view thereof. The inventor named this example a plate gibber joint.

  In this embodiment, the corrugated steel sheet web 10 and the lower flange 11 are joined structures in which a large number of steel plates 12 are arranged in the cross-sectional direction, and a long steel bar 14 is inserted into and engaged with the through holes 13 of the steel plate 12. The corrugated steel web 10 and the concrete lower floor slab 40 are joined.

  In this structure, the shearing force between the corrugated steel sheet web 10 and the concrete lower floor slab 40 in the bridge axis direction is resisted by the bearing strength of the steel plate 12 and the lower floor bridge concrete 40. The cross-sectional force in the direction perpendicular to the bridge axis is resisted by the shear strength of the perforated ribs formed by filling the through holes of the steel plate 12 through which the long steel bar 14 is inserted. What is necessary is just to adjust the dimension of the steel plate 12, the diameter and number of through-holes, and the diameter of the elongate steel bar 14 according to the cross-sectional force which acts on a girder.

  2 (a) and 2 (b) show the joining structure of the steel plate web 10 and the concrete lower floor slab 40 of the second embodiment of the present invention, and FIG. 2 (a) is a front view (FIG. FIG. 2B is a plan view of FIG. 2B. The inventor named this structure a perforbonded rib joint.

  A long strip steel plate 15 along the bridge axis direction is arranged and fixed on the steel flange 11 in the bridge axis direction. The strip steel plate 15 includes a plurality of through holes, and includes a plurality of reinforcing bars 16 that intersect the strip steel plate 15 through the plurality of through holes. In the actual example shown in FIGS. 2A and 2B, stud gibber 30 is disposed on the side surface of corrugated steel web 10 and the upper surface of lower flange 11, and these stud dibels 30 are respectively in reinforcing bar 16 and in concrete. It is the joining structure arrange | positioned so that it may join dynamically.

  In this embodiment, the shearing force between the corrugated steel sheet web 10 in the bridge axis direction and the concrete lower floor slab 40 is formed by filling the through holes of the strip-shaped steel plate 15 through which the reinforcing bars 16 are inserted with concrete. Resist with the shear strength of the perfor bonded ribs and the shear strength of the stud gibber. The cross-sectional force in the out-of-plane direction is resisted by the tensile strength of the stud gibber 30. The dimensions of the strip steel plate 15, the number and dimensions of the through holes of the strip steel plate 15, the diameter of the reinforcing bar 16, and the dimensions and number of the stud gibels 30 may be adjusted in accordance with the acting sectional force.

  3 (a) and 3 (b) show the joining structure of the corrugated steel web 10 and the concrete lower floor slab 40 of the third embodiment of the present invention. FIG. 3A is a front view (a view taken along the line CC in FIG. 3B), and FIG. 3B is a plan view thereof. The inventor has named this joint a block gibel joint.

  This embodiment shows an example in which a stud bar 30 is used in a joint structure in which a long steel bar 17 that holds the shape of the corrugated steel web 10 is arranged inside the corrugated steel web 10. The long steel bar 17 is fixed to the side surface of the corrugated steel web 10 in the figure. The long steel bar 17 may be a round bar, a deformed bar, a square bar, a shaped steel, a steel strip, or the like, and is fixed to the side surface of the corrugated steel web 10 by welding or the like.

  The shear shear strength between the corrugated steel sheet web 10 and the concrete lower floor slab 40 in the bridge axis direction is resisted by the shear strength of the stud gibel 30 and the bearing strength of the corrugated steel web 10 and the concrete lower floor slab 40. The cross-sectional force in the out-of-plane direction is resisted by the tensile strength of the stud gibber 30. The cross-sectional dimension and the number of the long steel bars 17 and the dimension and the number of the stud gibels 30 are adjusted according to the acting cross-sectional force.

  In the structure shown in FIGS. 3A and 3B, the concrete lower floor slab 40 is disposed on the lower flange 11, and only one side (inner side) of the corrugated steel web 10 is joined to the concrete lower floor slab. It is a format.

  In the structure in which the corrugated steel web 10 is embedded in the concrete lower floor slab 40 (a structure in which the concrete lower floor slab is joined to both surfaces of the corrugated steel web), the corrugated shape of the corrugated steel web 10 is changed to the concrete lower floor 40 itself. Therefore, the corrugated portion plays the role of a shear key and works effectively against the shear shear force in the bridge axis direction. However, as described above, when the joining of the concrete lower floor slab 40 and the corrugated steel web 10 is limited to one side of the corrugated steel web, the deformation of the corrugated steel web 10 can be freely performed in a direction not joined to the concrete lower floor 40. Therefore, it is difficult to expect the corrugated steel sheet web 10 to retain the shape of the concrete lower floor slab 40. Therefore, it is not appropriate to assume the effect of the shear key of the corrugated part in the design.

  In the structure shown in FIGS. 3A and 3B, the long steel bar 17 is fixed to the side surface of the corrugated steel web 10 so that the long steel bar 17 restrains the deformation of the corrugated steel web 10. As with the above-described embedded joint, the shear key effect of the corrugated portion is expected. The degree of the effect varies depending on the corrugated shape, the thickness of the concrete bottom slab 40, the strength of the concrete, and the strength of the steel bar 17, but when sufficient steel bar 17 is disposed, the portion of the concrete in contact with the corrugated steel web 10 is shown. Therefore, it is possible to reduce the number of stud dowels.

  In general, it is considered that the dedicated steel 17 contributes to the cross-sectional force in the out-of-plane direction where the bending moment is dominant. However, since it is difficult to restrain the deformation by the steel bar 17, It is not appropriate to resist the cross-sectional force with the steel bar 17.

  Therefore, the cross-sectional force in the out-of-plane direction is made to resist by the tensile strength of the stud gibber 30 installed on the corrugated steel web 10.

Next, with respect to the joint structure of the lower end of the steel plate web of the PC box girder bridge according to the present invention, a loading test using a test piece was performed on the cross-sectional force in the bridge axis direction and the perpendicular direction, and the corrugated steel plate web Since it was confirmed that there was no problem with the integrity of the lower floor slab, the experiment will be described below.
(A) About bridge axis direction shear shear strength confirmation experiment In the experiment, a total of four types of joint structures of two types in the bridge axis direction and two types in the web were arranged at the joint between the corrugated steel sheet web 10 and the concrete lower floor slab 40. This was done with the beam specimen 70.

  A side view of the specimen 70 is shown in FIG. 9 (a), and a front view thereof is shown in FIG. 9 (b). In the positions 71, 72, 73 of the joining structure shown in the figure, the plate gibber joint shown in FIG. 1 and the par shown in FIG. Three types of bonding structures equivalent to the fobond rib bonding and the block diver bonding shown in FIG. 3 were formed. In addition to this, in order to verify the effect of the steel bar of the block diver joint, a joint structure similar to that of the block gibel joint (herein referred to as a stud gibel joint) is disposed at the disposition position 74 except that the bar steel is not disposed. .

  As shown in FIGS. 9 (a) and 9 (b), both ends of the specimen 70 are supported by a support 75, and loads P are loaded evenly and stepwisely at two points in the bridge axis direction and at four points on both webs. The properties of each part, such as stress and deformation, were confirmed by a measuring device installed at each part of the specimen 70.

  In any of the connection positions 71, 72, 73, and 74 of the joint structure, elastic behavior is exhibited until a load is applied where a shearing shear force corresponding to the design use strength is applied to the joint, and no damage is confirmed. It was confirmed to be healthy.

  Further, it was confirmed that the shear shear force exceeding the designed ultimate strength was in a slight damage range even with respect to the load applied to the joint, and had sufficient strength.

(B) About a perpendicular direction bending strength confirmation experiment As shown in FIG. 10, the experiment was performed on a joint C of a specimen 80 typified by one side of a corrugated steel sheet web 10 for one wavelength of corrugated steel sheet and a concrete lower floor slab 40. Then, four specimens 80 each having the above-described four types of joint structures were prepared, and experiments were conducted.

  The load Q is measured by a measuring device installed on each part of the specimen 80 by loading a pure bending moment on the part of the joint structure via the corrugated steel web 10 using the loading beam 81 installed on the top of the corrugated steel web 10. Properties of each part, such as stress and deformation, were confirmed.

  In any of the joint structures, elastic behavior was exhibited up to load loading corresponding to the design use, and it was confirmed that no damage was observed and that the structure was sound. Moreover, it was confirmed that it has sufficient strength against load loading equivalent to the ultimate strength.

It is a front view (AA arrow line view of FIG.1 (b)) which shows the joining structure of the steel plate web of an Example, and a lower floor slab. FIG. 2 is a plan view of FIG. It is a front view (BB arrow line view of Drawing 2 (b)) showing the joining structure of the steel plate web of an example, and a lower floor slab. FIG. 3 is a plan view of FIG. It is a front view (CC arrow view of FIG.3 (b)) which shows the joining structure of the steel plate web of an Example, and a lower floor slab. It is a top view of Fig.3 (a). It is a front view of the PC box girder bridge using the conventional corrugated steel web. It is a perspective view of a prior art example. It is a perspective view of a prior art example. It is a front view of the PC box girder bridge using the conventional corrugated steel web. It is a front view of a prior art example. It is a side view of Fig.8 (a). It is a side view of the test body of a shear strength experiment. It is a front view of the specimen of a shear strength test. It is a front view of the specimen of a bending strength experiment.

Explanation of symbols

1 PC box girder bridge 10 Corrugated steel web 11 Steel flange (lower flange)
DESCRIPTION OF SYMBOLS 12 Steel plate 13 Through-hole 14 Bar steel 15 Strip | steel-shaped steel plate 16 Reinforcement 17 Joining steel material 30 Stud diver 40 Concrete lower floor slab 50 Concrete upper floor slab 61 Through-hole 62 Through rebar 63 Bonding bar 70 Specimen 71, 72, 73, 74 Joining structure 75 Bearing 80 Specimen 81 Loading beam

Claims (3)

In a PC box girder bridge using a corrugated steel web, a flange is provided at the lower end of the corrugated steel web.
A large number of steel plates having through holes are fixed to the flange upper surface and the corrugated steel sheet web side surface in a posture in which the steel plate surface is vertical, and a long steel bar is locked to the steel plate through the through holes. A PC box girder bridge, wherein a concrete lower floor slab incorporating the steel plate and long steel bar is attached to the upper surface of the flange.   In a PC box girder bridge using a corrugated steel web, a long strip steel plate having a flange at the lower end of the corrugated steel web and having a large number of through holes is vertically fixed on the upper surface of the flange along the bridge axis direction. A plurality of reinforcing bars intersecting with the strip steel plate through the through hole, a portion contacting the lower floor slab of the corrugated steel sheet web side surface and a top surface of the flange are provided with stud gibels, the strip steel plate, A PC box girder bridge, wherein a concrete lower floor slab incorporating a large number of reinforcing bars and stud studs is attached to the upper surface of the flange.   In a PC box girder bridge using a corrugated steel web, a flange is provided at the lower end of the corrugated steel web, and a long steel bar is fixed to the side of the corrugated steel web above the flange along the bridge axis direction. A PC box girder bridge comprising a stud gibber in a portion in contact with a floor slab, and a concrete lower floor slab incorporating the long steel bar and the stud diver is attached to an upper surface of the flange.

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