JP2007046238A - Steel composite concrete precast floor slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel composite precast floor slab which can keep costs low because a bottom steel plate does not have to be bent along an undersurface of a haunch by enabling an additional bar along the haunch to be arranged in the inverted trapezoid-shaped haunch in a direction perpendicular to a girder, and which can integrate a precast floor slab, a notch and a main girder together. <P>SOLUTION: This steel composite concrete precast floor slab, which is constituted by combining a concrete undersurface with the bottom steel plate, is characterized as follows: an additional-bar fitting and inserting notch, from which mountain parts of the additional bar along the shape of the inverted trapezoid-shaped haunch are protruded at proper intervals in the direction of a bridge axis, and a stud-bolt fitting and inserting notch for fitting and inserting a stud bolt, which is fixedly provided in the flange of the main girder, are formed in the haunch forming part of the bottom steel plate; a bridge-axis-direction bar, a bar perpendicular to the bridge axis, and the additional bar along the shape of the inverted trapezoid-shaped haunch are arranged on the bottom steel plate in a state in which both ends of the additional bar are supported on the bar perpendicular to the bridge axis, and in which the mountain parts are protruded from the additional-bar fitting and inserting notch of the bottom steel plate; and the bottom steel plate is combined with the concrete undersurface wherein the concrete is placed in locations except a stud-bolt fitting and inserting hole communicating with the stud-bolt fitting and inserting notch formed on the bottom steel plate. <P>COPYRIGHT: (C)2007,JPO&INPIT

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.

  Stitch fixed to the main girder flange and the core rebar insertion notch for projecting the peak of the core rebar along the inverted trapezoidal haunch shape at appropriate intervals in the bridge axis direction on the bottom steel plate haunch forming portion A stud bolt insertion notch for inserting the bolt is formed, and on this bottom steel plate, the bridge axis direction reinforcing bar, the bridge axis perpendicular reinforcing bar and the haunch-shaped core reinforcing bar are at both ends of the core reinforcing bar in the direction perpendicular to the bridge axis. A stud bolt insertion hole which is supported by the reinforcing bar and is arranged in a state where the peak portion protrudes from the core reinforcing bar insertion notch portion of the bottom steel plate and communicates with the stud bolt insertion notch portion formed in the bottom steel plate. The present invention provides a steel composite concrete precast floor slab that is made by placing concrete.

  Preferably, in the above, a steel composite concrete precast slab in which stud bolts are attached to the bottom steel plate surface facing the main girder flange surface is provided.

  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 steel composite concrete precast floor slabs, it is not necessary to bend the bottom steel plate along the bottom surface of the haunch because the center reinforcing bars along the haunch can be inserted into the inverted trapezoidal haunch in the direction perpendicular to the girders. 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 reinforcing bar 6, and a core reinforcing bar 7 are arranged. In the drawing, the bridge axis direction reinforcing bars 5 and the bridge axis perpendicular direction reinforcing bars 6 are omitted except for the vicinity of the center reinforcing bar 7. The center reinforcing bar 7 has a shape substantially in line with the shape of the inverted trapezoidal haunch formed on the main girder flange, and the center reinforcing bar 7 has a center reinforcing bar notch 4a in the notch 4 of the precast floor slab 1. The ridges 7a are inserted and protruded from the bottom surface of the bottom steel plate, and both ends 7b and 7b are disposed 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 the binding wire together to integrate them.

  The concrete 2 is placed on the bottom steel plate 3 while leaving the stud bolt insertion holes 14 extending from the stud bolt insertion notches 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 and the stud bolt insertion notch communicate with each other.

  In placing concrete, although not shown, a frame 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 top 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.

  Next, 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 Reinforcing Bars 8 Stud Bolts to Prevent 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 that is composed of a bottom steel plate synthesized on the bottom surface of a concrete, projecting ridges of core reinforcing bars along the inverted trapezoidal haunch shape are projected at appropriate intervals in the bridge axis direction on the bottom steel plate haunch forming portion. A notch for inserting a reinforcing bar and a notch for inserting a stud bolt to which a stud bolt fixed to the main girder flange is inserted are formed. On this bottom steel plate, a bridge axis rebar and a bridge axis perpendicular reinforcement are formed. And an inverted trapezoidal haunch shaped reinforcing bar with both ends of the reinforcing bar supported by the reinforcing bars perpendicular to the bridge axis, with the peaks protruding from the notch for inserting the reinforcing bar of the bottom steel plate and the bottom steel plate A steel composite concrete formed by synthesizing a bottom steel plate on the concrete bottom surface, wherein the concrete is placed leaving a stud bolt insertion hole communicating with the stud bolt insertion notch formed in Over door precast floor slab.   The steel composite concrete precast slab formed by synthesizing a bottom steel plate on a concrete lower surface according to claim 1, wherein stud bolts are attached to the bottom steel plate surface facing the main girder flange surface at appropriate intervals in the bridge axis direction. .

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