JP3799350B2 - Mechanism for preventing falling concrete in concrete bridges - Google Patents

Description

  The present invention relates to a mechanism for preventing a fall of concrete in a concrete bridge. More specifically, the present invention relates to an interstitial concrete fall prevention mechanism in a concrete bridge that prevents the fall of concrete placed in a gap between PC concrete bridge girders arranged in parallel with each other.

  One of the bridge girder structures is a prestressed concrete girder (hereinafter referred to as “PC girder”). This PC girder has the advantages that it has less noise and vibration and is easy to maintain, and in particular, the pretension type PC girder is a factory product and has good quality control and can shorten the construction period.

  PC girders are main girders made of prestressed concrete with a rectangular, box-shaped, and T-shaped cross section, and are installed in parallel between the abutments or between the abutments in a direction perpendicular to the girders with a required interval. is there. Then, a floor slab (hereinafter referred to as “spaced floor slab”) is constructed by placing the concrete between the PC girders in the gap.

  This PC floor slab has a gap and cracks between it and the PC girder due to vibrations caused by running the vehicle over a long period of time, and rainwater infiltrates into the gaps and cracks, causing concrete to collapse from the inside and falling. The problem of doing is happening.

  Therefore, as shown in FIG. 6, as a measure for preventing the concrete piece from falling, a steel plate 102 is placed between the PC girders 101 after placing a packed floor slab in the gap between the PC girders 101. A means for fixing to the PC girder 101 with a bolt 103 or the like is taken.

  However, in this prevention mechanism, the steel plate, bolts, etc. corrode when exposed to wind and rain for a long period of time, and the concrete piece supported by the steel plate falls with the steel plate and travels under the padded floor slab There is a problem that causes accidents such as contact with pedestrians.

  Further, there is a problem that a gap is generated between the PC girders by dropping the slab floor slab, and a tire of a traveling vehicle is fitted into the gap to cause an accident.

  The present invention was devised in view of the above points, and prevents falling of a deteriorated concrete piece and steel plate by supporting the steel plate placed between the PC girders with a uniform force. The purpose of the present invention is to provide a mechanism for preventing the falling of concrete in a concrete bridge in a concrete bridge.

  In order to achieve the above-described object, the concrete fall prevention mechanism in a concrete bridge according to the present invention is a concrete that is placed in a gap of a PC girder installed between bridge piers at a required interval in a direction perpendicular to the bridge axis. In the fall prevention mechanism of the interstitial concrete constructed by the above, a fall prevention plate attached between the PC girders so as to cover the bottom surface of the interstitial concrete, and the PC girders located below the fall prevention plate and coupled to each other A string-like support member that is stretched between the cross-beams that is constructed to perform the cross-beam, and a cross-girder in which the string-like support member is stretched in an arch shape between the fall prevention plate and the string-like support member A plurality of vertical support members arranged in a vertical manner so that the length sequentially increases toward the center.

  Here, the fall floor slab is received by the fall prevention plate to be deteriorated and collapsed due to rainwater inundation for a long period of time, and is stretched through a vertical support member arranged vertically on the lower face of the fall prevention plate. The string-like support material applies a uniform support pressure to the fall prevention plate, and it is possible to completely prevent the falling concrete from falling.

  A mechanism in which the string-like support material is formed of a PC steel material, a support member insertion hole is drilled in the cross beam, and both ends of the string-like support material are inserted into the support member insertion hole and are stretched by fastening metal fittings; By doing so, the attachment work of the string-like support member can be performed very easily.

  In addition, the vertical support material is bifurcated so that both ends of the fall prevention plate can be supported, and the length of the vertical support material can be freely adjusted. Can be done easily.

  According to the interstitial concrete fall prevention mechanism in the concrete bridge of the present invention, the fall prevention plate provided between the PC girders along the bottom surface of the interstitial concrete slab is reliably supported by a uniform force from the vertical direction. It is possible to prevent the concrete piece from falling.

  In addition, the fall prevention mechanism can be easily attached by simply drilling the support member insertion hole in the cross beam to the existing concrete bridge, and the string-like support member is stretched in a reverse arch shape by the vertical support member. Therefore, a uniform support pressure is always maintained on the fall prevention plate.

  In addition, by adopting a configuration in which the vertical support material is bifurcated, even a wide fall prevention plate can be supported stably by supporting both side ends thereof.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings to provide an understanding of the present invention.

FIG. 1 is a cross-sectional explanatory view of a PC girder in a space packed concrete fall prevention mechanism in a concrete bridge to which the present invention is applied, and FIG. 2 is a side explanatory view of FIG.
A plurality of prestressed PC girders 1 having a T-shaped cross section are installed on a bridge pier 2 in parallel with a predetermined interval. Then, a concrete floor slab 3 is constructed by placing concrete concrete in the gap between each PC girder 1.

  Further, a fall prevention plate 4 made of a strip-shaped steel plate is attached between the PC girders 1 by a binding member 11 such as a bolt along the gap between the PC floor slabs 3 and the PC girders 1. Therefore, the fall prevention plate 4 prevents the collapsing floor slab 3 from collapsing.

  Moreover, the prestressed concrete cross beam 5 formed in order to connect each PC beam 1 for every required space | interval along the longitudinal direction of each PC beam 1 is constructed | assembled. Accordingly, a plurality of PC girders 1 that are arranged side by side by this cross girder 5 and are constructed on the pier 2 are firmly connected.

  Next, as shown in FIG. 3, two support member insertion holes 10 are penetratingly provided at a substantially central position of each cross beam 5. In order to pass the elastic string-like support material 6 formed of PC steel between the cross beams 5, both ends of the string-like support material 6 are inserted into the support member insertion holes 10 and jacks or the like are inserted. It is stretched between the cross beams 5 by the fastening hardware 8. Therefore, the string-like support member 6 is in a state of being provided at a position below the fall prevention plate 4 attached to the bottom surface of the padding floor slab 3.

  Therefore, a plurality of vertical support members 9 each having a length that gradually increases from the facing beam 5 toward the center are arranged between the fall prevention plate 4 and the string-like support member 6 at regular intervals. It is arranged in a vertical shape and is stretched so as to have an inverted arch shape in a state where tension is applied to the string-like support member 6.

  FIG. 4 shows another example of a mechanism for preventing the fall of a concrete in a concrete bridge to which the present invention is applied. The vertical support member 9 has a V-shape so as to support both ends of the fall prevention plate 4. A branch is formed.

  Therefore, a length adjusting unit 7 is provided in the middle of the vertical support member 9. The length adjusting portion 7 is formed by rotating the connecting cylindrical portion 12 to the left and right sides by cutting the middle of the vertical supporting member 9 and connecting them in a state where they are screwed together by the connecting cylindrical portion 12. 9 is a mechanism that can be freely adjusted in length.

  Therefore, the vertical support member 9 and the string-like support member 6 are joined to each other by tightly connecting the string-like support member 6 by winding and tightening the string-like support member 6 by the fastening annular member 13 provided at the lower end of the vertical support member 9. Moreover, the vertical support member 9 and the fall prevention plate 4 are joined by a semicircular receiving plate 14 that is mounted on the upper end of the vertical support member 9 in a state that it can be rotated in all directions by bolts 15.

  Accordingly, the vertical support member 9 is provided between the string-like support member 6 and the fall prevention plate 4 in a state where the string-like support member 6 is stretched by the length adjusting unit 7, and further, the vibration of the PC girder or the earthquake The vertical support member 9 can be prevented from being broken due to the semicircular receiving plate 14 with respect to the time shift.

  Here, the fall prevention plate is not necessarily formed of a steel plate, and may be made of any material such as an aluminum plate, a stainless plate, or a synthetic resin plate as long as it has rust prevention and durability. However, it is desirable to use a steel plate that is particularly excellent in strength and durability.

  Further, the string-like support material is not necessarily formed of a PC steel material, and any material such as a synthetic resin fiber body may be used as long as it has toughness and elasticity.

  In the present invention having the above-described configuration, as shown in FIG. 5, it is possible to provide an interstitial concrete fall prevention mechanism for a new construction or an existing concrete bridge. Therefore, a plurality of vertical support members 9 having a length that is sequentially increased from the facing cross beam 5 toward the center with respect to the fall prevention plate 4 that prevents the PC floor slab 3 from collapsing due to deterioration. The stress applied to the fall prevention plate 4 by each vertical support member 9 is uniform by arranging it vertically so as to form a reverse arch shape with tension applied to the string support member 6 at regular intervals. Thus, it is possible to always support the fall prevention plate 4 with a constant force.

  Further, by stretching the string-like support material 6 between the cross beams 4, stresses in the directions of arrows A and B are applied to the cross beams 4. Accordingly, since substantially equal stresses are applied in opposite directions, the stresses cancel each other, and the cross beam 5 is not stressed. Accordingly, it is not necessary to reinforce the cross beam 5 and it is possible to sufficiently cope with an existing PC beam.

  In addition, the installation of the interstitial concrete fall prevention mechanism of the present invention can be easily performed by making a hole in the horizontal girder, while maintaining the strength of the PC girder without directly touching the PC girder. Can be attached.

  The vertical support member has a reverse arch shape that is closer to an arch shape as the distance between the support members is shorter or the number of the vertical support members is larger, and a flat support pressure can be applied to the fall prevention plate.

  Further, the bending moment to the floor slab due to vehicle travel is reduced by the vertical moment by the string-like support material and the vertical support material, and it is possible to prevent cracking of the floor slab.

  In the present invention, the fall floor plate receives a fall floor plate due to rainwater inundation for a long period of time by the fall prevention plate, and the fall of the fall prevention plate due to damage of a bolt or the like is made uniform by the vertical support member and the string-like support member. It is possible to completely prevent the falling concrete from falling by supporting with the support pressure.

It is a section explanatory view of the PC girder in the space concrete prevention mechanism in the concrete bridge to which the present invention is applied. It is side surface explanatory drawing in FIG. It is explanatory drawing which shows an example of the space | gap concrete fall prevention mechanism in the concrete bridge to which this invention is applied. It is explanatory drawing which shows the other example of the interstitial concrete fall prevention mechanism in the concrete bridge to which this invention is applied. It is explanatory drawing which shows the effect | action state of the space-filling concrete fall prevention mechanism in the concrete bridge to which this invention is applied. It is explanatory drawing which shows an example of the conventional filling concrete fall prevention means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 PC girder 2 Bridge pier 3 Packing floor slab 4 Fall prevention board 5 Horizontal girder 6 String-like support material 7 Length adjustment part 8 Fastening metal fitting 9 Vertical support material 10 Support member insertion hole 11 Binding member 12 Connection cylindrical part 13 Annular member for fastening 14 Base 15 Bolt

Claims (4)

In the fall prevention mechanism of the interstitial concrete constructed by concrete cast in the gap of the PC girder installed between the piers with a required interval in the direction perpendicular to the bridge axis,
A fall prevention plate attached between the PC girders so as to cover the bottom surface of the padded concrete;
A string-like support member that is positioned below the fall prevention plate and stretched between cross beams constructed to connect the PC girders;
Between the fall prevention plate and the string-like support material, the string-like support material is arranged in a vertical shape so that the length sequentially increases toward the center of the cross beam as if stretched in an arch shape. A mechanism for preventing fall of concrete in a concrete bridge in a concrete bridge, comprising a plurality of vertical supports. 2. The concrete according to claim 1, wherein the string-like support member is formed of a PC steel material, and both ends thereof are inserted into support member insertion holes that are perforated in a transverse girder and are stretched by fastening metal fittings. A mechanism for preventing concrete from falling between bridges. The mechanism for preventing fall of a concrete in a concrete bridge according to claim 1 or 2, wherein at least one end of the upper and lower ends of the vertical support member is fixed to a fall prevention plate or a string-like support member. The vertical support member is bifurcated to support both side ends of the fall prevention plate, and further includes a length adjusting unit that can freely adjust the length of the vertical support member. A mechanism for preventing the fall of a compacted concrete in a concrete bridge according to 2 or 3.

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