JP4568656B2 - Steel synthetic concrete precast slab - Google Patents

Description

  The present invention relates to a precast slab for a bridge in which a bottom steel plate is synthesized on a concrete lower surface, and more particularly, to a steel synthetic precast slab using a haunch-shaped core reinforcing bar at a portion corresponding to a haunch.

  A precast floor slab in which a bottom steel plate is synthesized on a concrete lower surface is well known (Patent Document 1).

  In principle, the floor slab is provided with a haunch on the main girder, and it is preferable to arrange the core rebar in the direction perpendicular to the girder along the lower surface of the haunch (Non-Patent Document 1). In the case of a floor slab, it is not necessary (Non-Patent Document 2).

  In the case of a precast floor slab, it is thought that the haunch structure does not need to be provided on the haunch along the lower surface of the haunch due to the haunch structure.

Japanese Patent No. 2832522

Road Bridge Specification / Explanation Japan Road Association 252-253 Steel Structure Design Guidelines Japan Society of Civil Engineers 62-63

  Incidentally, several haunch structures in the steel composite precast slab are illustrated.

  FIG. 11 shows an example of the steel composite precast slab 1 in which the inverted trapezoidal haunch 12 is formed on the lower surface of the concrete 2 in advance. The floor slab 1 is synthesized with concrete 2 by bending the bottom steel plate 3 along the haunch 12 in advance. In this floor slab, the positions corresponding to the stud bolts 11 on the flange 9a of the main girder 9 are boxed 41 at an appropriate interval. Non-shrink mortar 13 is placed and installed at 41 locations.

  FIG. 12 shows an example of a steel composite precast floor slab 1 in which a haunch is not formed in advance on the lower surface of the concrete 2. This floor slab 1 is continuously punched 42 on the main girder 9 and placed on a haunch-height die steel 14 attached to both sides of the flange 9a of the main girder 9. It will be installed.

  FIG. 13 shows an example of a steel composite precast slab 1 in which a haunch is not formed on the lower surface of the concrete 2 in advance. This floor slab 1 is continuously punched 42 on the main girder 9 and placed on a mold steel plate 15 for forming a haunch that is extended from both sides of the upper surface of the flange 9a of the main girder 9 and has 42 consecutive punches. A straight core rebar 71 is placed on the non-shrink mortar 13 and installed.

  In these drawings, 5 is a reinforcing bar arranged in the bridge axis direction, and 6 is a reinforcing bar arranged in the direction perpendicular to the bridge axis.

  However, not all of these structures are able to utilize a scissor rebar in the hunch, but have other challenges.

  In the case of FIG. 11, since the bottom steel plate is bent along the floor slab haunch shape, the processing cost is enormous, leading to an increase in cost.

  The thing of FIG. 12 has a synthetic | combination problem in integration with a precast part rather than partial box extraction, since the upper part position of a main girder is concrete-placed continuously. Stress concentration occurs because the haunch shape is rectangular. In the shape steel for formwork, the vertical installation position differs depending on the longitudinal section of the main girder, which causes problems in terms of process and cost.

  In the case of FIG. 13, the formwork steel plate is attached to the precast bottom steel plate by welding and can be adjusted to the current haunch height. However, the formwork steel plate continuous in the main girder direction is three-dimensional. Since the change cannot be followed, a gap is generated between the upper surface of the main girder and the steel plate for formwork.

  In the steel composite precast floor slab integrated with the inverted trapezoidal shape haunch part, the present invention has problems and several problems that a central reinforcing bar having a shape along the haunch shape cannot be inserted into the haunch part. Is to be solved as described below.

  The present invention provides the following means for solving the above problems.

On the bottom steel plate where the inverted trapezoidal haunch with one side of the bottom steel plate is formed , the peak portion of the central reinforcing bar along the haunch-shaped peak portion of the inverted trapezoidal haunch protrudes at an appropriate interval in the bridge axis direction. A notch part for inserting a core reinforcing bar and a notch part for inserting a stud bolt for inserting a stud bolt fixed to the main girder flange are formed, and a bridge axis direction reinforcing bar and a bridge axis perpendicular direction reinforcing bar are formed on the bottom steel plate. a precaution rebar along the haunches inverted trapezoidal shape arranged, the ends of precaution rebar is supported by the bridge axis perpendicular, placing in a state of protruding from the fitting interpolating notch precaution rebar bottom steel plates Yamabe In addition, a steel composite concrete precast floor slab formed by synthesizing the bottom steel plate on the bottom surface of the concrete is formed by leaving the stud bolt insertion hole communicating with the stud bolt insertion notch formed on the bottom steel plate. provide.

Preferably, the bottom steel plate provides a steel composite concrete precast floor slab in which stud bolts are attached at an appropriate interval in the bridge axis direction on the opposite surface of the main girder flange surface on which the floor slab is placed .

  In the steel composite concrete precast slab, since the core reinforcement along the haunch can be put in the inverted trapezoidal haunch in the direction perpendicular to the girders, the steel structure design guidelines of the Japan Society of Civil Engineers can be met.

  In the steel composite concrete precast slab, since the core rebar along the haunch can be inserted into the inverted trapezoidal haunch in the direction perpendicular to the girders, it is not necessary to bend the bottom steel plate along the lower surface of the haunch, reducing the cost. In addition, it is possible to measure the integrity of the precast floor slab, the notch and the main girder.

  1 to 5 show an embodiment of the present invention, FIG. 1 is a plan view of a bottom steel plate, FIG. 2 is a plan view of a steel synthetic concrete precast slab formed by synthesizing the bottom steel plate, and FIG. FIG. 4 is a sectional view taken along line AA in FIG. 2, FIG. 4 is a sectional view taken along line BB in FIG. 2, and FIG. 5 is a sectional view taken along line CC in FIG.

  First, based on FIG. 1, the bottom steel plate which forms this invention is demonstrated.

  The bottom steel plate 3 has a flat plate shape, and a plurality of cutout portions 4 are cut out at appropriate intervals in the bridge axis direction. This notch portion 4 is a core reinforcing bar along the inverted trapezoidal haunch shape at an appropriate interval in the bridge axis direction at the portion corresponding to the flange when the bottom steel plate 3 is placed on the main girder, that is, where the haunch portion is formed. And a stud bolt insertion notch 4b for fitting a stud bolt fixed to the main girder flange.

  As shown in FIG. 1, the shape of the notch portion 4 may be a combination of a notch portion 4a having a length necessary for inserting a precautionary reinforcing bar and a notch portion 4b for inserting stud bolts with different shapes. As shown in FIG. 9, both of the cutout portions 4a and 4b are used in the same shape, and as shown in FIG. 10, the cutout portion 4a for inserting the core reinforcing bar, the cutout portion 4b for inserting the stud bolt, It may be what it does and is not limited.

  Next, the structure of the precast slab according to the present invention will be described with reference to FIGS.

  On the bottom steel plate 3, a bridge axis direction reinforcing bar 5, a bridge axis perpendicular direction reinforcing bar 6 and a core reinforcing bar 7 are arranged. In the figure, the bridge axis direction reinforcing bars 5 and the bridge axis perpendicular direction reinforcing bars 6 are omitted except for the vicinity of the guard bars 7. The core rebar 7 has a shape substantially in line with the shape of the inverted trapezoidal haunch formed on the main girder flange. The ridges 7a are inserted and protruded from the bottom surface of the bottom steel plate, and both ends 7b and 7b are arranged so as to be in contact with the reinforcing bars 6 perpendicular to the bridge axis. The both ends 7b and 7b are attached to the bridge axis perpendicular reinforcing bar by, for example, taking a predetermined lap joint length and winding and tying a binding wire.

  The concrete 2 is placed on the bottom steel plate 3 while leaving the stud bolt insertion hole 14 extending from the stud bolt insertion notch 4b cut out in the bottom steel plate 3 to the top surface of the precast floor slab 1. The stud bolt insertion hole 14 communicates with the stud bolt insertion notch.

  In placing concrete, although not shown, a mold is installed around the bottom steel plate 3 and the stud bolt insertion hole 14 extends from the stud bolt insertion notch 4b to the upper surface of the precast floor slab 1. The mold 15 is placed in this portion so that is formed.

  The stud bolt insertion hole 14 becomes a concrete inflow hole when the precast floor slab 1 is on the flange 9a of the main girder 9 and a haunch is formed.

  The mold and the mold 15 installed around the bottom steel plate 3 after curing are removed.

  8 is a stud bolt for preventing misalignment, and is fixed at an appropriate interval in the main girder direction on the bottom surface of the bottom steel plate 3 corresponding to the main girder flange without a notch.

  6 to 8 show an aspect of installation of a steel composite concrete slab formed by synthesizing a bottom steel plate placed on the main girder, FIG. 6 is a diagram corresponding to FIG. 3, FIG. 7 is a diagram corresponding to FIG. FIG. 8 corresponds to FIG.

  First, the stud bolt 11 to be inserted into the notch portion 4b for stud bolt insertion formed in the precast floor slab 1 is fixed on the upper surface of the flange 9a of the main girder 9 in the bridge axis direction.

  The precast floor slab 1 is carried out to the site, and the stud bolt 11 fixed to the flange 9a of the main girder 9 is temporarily inserted into the stud bolt insertion hole 14 to adjust the installation position and installation level. After various joining, the formwork 10 for forming the inverted trapezoidal haunch 12 is fixed on both sides of the flange 9a of the main girder 9 from the both sides to the bottom steel plate 3 of the precast floor slab 1.

  Subsequently, from the stud bolt insertion hole 14 penetrating from the surface of the concrete 2 formed on the precast floor slab 1 to the bottom surface of the bottom steel plate 3, between the bottom surface of the bottom steel plate 3 of the precast floor slab 1 and the top surface of the flange 9 a of the main girder 9. Concrete such as a non-shrink mortar 13 is placed, and a haunch 12 is formed between the precast floor slab 1 and the flange 9 a of the main girder 9.

  The concrete such as non-shrink mortar 13 placed on site, the precast floor slab 1 and the main girder 10 are stud bolts 11 fixed on the upper surface of the main girder 10 and the bottom surface of the bottom steel plate 3 of the precast floor slab 1. Are firmly integrated with a stud bolt 8 for preventing misalignment.

  The formwork 10 is removed after concrete curing.

It is a top view which shows the aspect of implementation of the bottom steel plate used for the steel synthetic concrete precast floor slab which concerns on this invention. It is a top view of the steel synthetic concrete precast slab formed by synthesize | combining the bottom steel plate which shows the embodiment of this invention. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is sectional drawing which shows the part corresponding to FIG. 2 which shows the aspect of the installation on the main girder of the steel synthetic concrete floor slab formed by synthesize | combining the bottom steel plate which concerns on this invention. It is sectional drawing which shows the part corresponding to the same FIG. It is sectional drawing which shows the location corresponding to FIG. It is a top view which shows the Example of another shape of the notch part shown in FIG. It is a top view which shows the Example of another shape of the notch part shown in FIG. It is sectional drawing which shows the haunch construction part of the conventional steel synthetic concrete steel plate. It is sectional drawing which shows the haunch construction part of the conventional steel synthetic concrete steel plate. It is sectional drawing which shows the haunch construction part of the conventional steel synthetic concrete steel plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Precast floor slab 2 Concrete 3 Bottom steel plate 4 Notch part 4a Notch part for insertion of core rebar for 4a Notch part for stud bolt insertion 5 Reinforcing bar arranged in the bridge axis direction 6 Reinforcing bar arranged in the direction perpendicular to the bridge axis 7 Stud Reinforcement 8 Stud Bolt for Displacement 9 Main Girder 9a Flange 10 Mold 11 Stud Bolt 12 Haunch 13 Non-Shrink Mortar 14 Stud Bolt Insertion Hole 15 Mold

Claims (2)

In a steel composite concrete precast slab formed by synthesizing a bottom steel plate on the bottom surface of the concrete , an inverted trapezoidal shape is formed at an appropriate interval in the bridge axis direction on the bottom steel plate where an inverted trapezoidal haunch with the bottom steel plate as one side is formed. A notch for inserting a core rebar that protrudes from the peak of the core rebar along the haunch-shaped peak of the haunch, and a notch for inserting a stud bolt that fits a stud bolt fixed to the main girder flange are formed. and, this bottom a steel sheet arranged and precautions rebar along the haunches shape of Hashijiku direction reinforcing bar and Hashijiku perpendicular rebar and inverted trapezoidal shape, and supports both ends of precaution rebar bridge axis perpendicular, bottom and crest Placing the concrete with the stud bolt insertion hole communicating with the notch for stud bolt insertion formed in the bottom steel plate while being arranged in a state protruding from the notch for insertion of the steel bar core reinforcement Special to be Steel synthetic concrete precast slab formed by combining the bottom steel plate concrete underside to. 2. The bottom steel plate has a bottom steel plate attached to the bottom surface of the concrete according to claim 1, wherein stud bolts are attached to the opposite surface of the main girder flange surface on which the floor slab is placed at an appropriate interval in the bridge axis direction. A steel synthetic concrete precast floor slab.

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