JP2015178741A - Pc box girder bridge, and method for constructing lower floor board concrete below steel flange connected to wavy steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PC box girder bridge having a lower floor board concrete below a steel flange connected to a wavy steel plate, which is free from forming a puddle on the upper face of the lower floor board concrete below the steel flange and thus excellent in durability, and to provide a method for constructing the lower floor board concrete below the steel flange connected to the wavy steel plate as part of the PC box girder bridge.SOLUTION: The PC box girder bridge includes, at least, a wavy steel plate 5, a steel flange 1 connected to the wavy steel plate 5, a perfobond rib 2 and stud dowels 4 extending downward from the lower face of the steel flange 1, and a lower floor board concrete 7 in which the perfobond rib 2 is embedded. The perfobond rib 2 is provided with a first hole 2a through which a reinforcement 6 is passed, and a second hole 2b which is opened in a boundary region with the steel flange 1. The second hole 2b serves as an air vent hole when constructing the lower floor board concrete 7.

Description

  The present invention relates to a PC box girder bridge and a method for constructing lower floor board concrete below a steel flange connected to a corrugated steel plate constituting the PC box girder bridge.

  Concerning PC bridges, corrugated steel web bridges with concrete webs replaced by corrugated steel sheets are excellent construction due to high prestressing efficiency due to the accordion effect and high shear buckling performance of main girder weight, corrugated steel sheets It is a structure that has both excellent properties and excellent economics resulting from the omission of stiffeners and the like. For example, Patent Document 1 discloses a technique related to a PC box girder bridge to which a corrugated steel plate is applied.

  Here, the configuration of a conventional PC box girder bridge is shown in FIG. As shown in the figure, the PC box girder bridge B has an upper floor concrete S1 and a lower floor concrete S2 connected by left and right corrugated steel plates W, and has a box shape in a longitudinal section perpendicular to the bridge axis.

  In the PC box girder bridge B shown in the figure, the configuration of the connecting portion (VI portion in FIG. 5) between the corrugated steel plate W and the lower floor concrete S2 will be described with reference to FIG. In addition, in FIG. 6, illustration of lower floor board concrete is abbreviate | omitted for easy understanding.

  The lower end of the corrugated steel sheet W is connected to a steel flange F. On the bottom surface of the steel flange F, a perforated rib R is attached at the center position, and a large number of stud dowels SD are attached to the left and right positions. .

  The perforated rib R is provided with a hole Ra through which the reinforcing bar RS passes, and the perforated rib R and a large number of stud dowels SD are embedded in the lower floor concrete S2 with a reinforcing bar (not shown) inserted therethrough. The corrugated steel sheet W and the lower floor board concrete S2 are connected via the steel flange F.

  As shown in FIG. 6, the steel flange F has a large number of holes Fa through which air that may be generated during construction of the lower floor board concrete is drawn. The air vent hole Fa has a diameter of about φ30 mm, for example, and is formed at a frequency of several per corrugated steel plate. It will be further described with reference to FIG. 7 that the air at the time of placing concrete is removed through the air vent hole Fa.

  As shown in the figure, the formwork K is assembled below the steel flange F connected to the corrugated steel sheet W, and fresh concrete C is filled into the formwork K. When the fresh concrete C is filled, the air in the mold K is pushed by the concrete C and moves. If the hole Fa is not opened in the steel flange F, a part of the moved air stays below the steel flange F, resulting in an air pocket.

  In the conventional construction, since the hole Fa is opened in the steel flange F, the air that has been pushed and moved by the concrete C is discharged upward through the hole Fa (X direction) and below the steel flange F. It is possible to eliminate the occurrence of air accumulation.

  However, with this conventional construction method, it has been found that the following problems arise due to the opening of the hole Fa in the steel flange F. This new problem will be described with reference to FIG.

  When the fresh concrete C is hardened and the lower floor board concrete S2 is formed, the moisture moves upward in the hardening process of the concrete, and the aggregates and the like move downward. Some depression will occur. And when this depression part exists under the steel flange F, this becomes the space | gap G and a water pool will arise in this space | gap G through the hole Fa.

  In order to suppress the occurrence of this water pool, post-installation of filling the gap G with resin has been carried out, but there is a question about the durability of the filled resin, which is a resin compared to concrete. There is a high possibility that a new puddle will occur when the part deteriorates over time.

  Even if the gap G does not occur on the upper surface of the lower floor board concrete S2 during the hardening process of the concrete, the water flows into the upper surface of the lower floor board concrete S2 through the hole Fa of the steel flange F, and the stud gibber SD or the reinforcing bar It cannot be denied that it causes corrosion of RS.

  Thus, in order to guarantee the air venting which becomes a problem at the time of construction of the lower floor board concrete S2, a large number of holes Fa are opened in the steel flange F, so that water can be formed on the upper surface of the lower floor board concrete S2 through the holes Fa. It is a new problem to cause accumulation.

JP 2006-316589 A

  The present invention has been made in view of the above-described problems, and relates to a PC box girder bridge provided with a lower floor board concrete below a steel flange connected to a corrugated steel sheet. Therefore, an object of the present invention is to provide a PC box girder bridge having high durability and a method of constructing lower floor board concrete below a steel flange connected to a corrugated steel plate constituting the PC box girder bridge. Yes.

  In order to achieve the above object, a PC box girder bridge according to the present invention includes a corrugated steel sheet, a steel flange connected to the corrugated steel sheet, a perforbond rib and a stud divel extending downward from the lower surface of the steel flange, and a perfor bond. A PC box girder bridge having at least a lower floor board concrete in which a rib is embedded, and the perforated rib has a first hole opened in a boundary region between a first hole that penetrates a reinforcing bar and a steel flange. Two holes are provided, and the second hole is an air vent hole when the lower floor board concrete is constructed.

  In the PC box girder bridge of the present invention, instead of opening an air vent hole for lower floor plate concrete construction in the steel flange, an air vent hole (first in the boundary region with the steel flange of the perforated rib extending downward from the lower surface of the steel flange is provided. This is characterized by the fact that two holes) are opened.

  Since there is no air vent hole in the steel flange, water cannot enter under the steel flange through the air vent hole, causing a problem of water pooling. Even if a gap is generated at a position below the steel flange, it is not necessary to perform post-installation such as injecting resin into the gap.

  In addition, since the air vent hole (second hole) is opened in the boundary area between the perforbond ribs and the steel flange, the air pressed by the fresh concrete filled in the mold frame will have this air vent hole. Therefore, it is discharged upward through the space between the steel flange and the formwork, and it is possible to eliminate the occurrence of air pockets at the time of placing concrete under the steel flange.

  Here, in the perforated rib, the first hole through which the reinforcing bar passes is opened at a position near the center of the longitudinal width of the rib, and the second hole for air venting is the upper edge of the rib, that is, the steel flange. It is established in the border area. Since the second hole for venting air is formed at the upper edge of the rib, it is suitable as an air escape place that tends to gather upward when filling concrete.

  Here, the first hole may be an elongated hole extending downward from the boundary region with the steel flange, and the second hole may be included in the first hole. .

  According to this aspect, it is not necessary to individually adjust the processing positions of the first hole and the second hole, and it is possible to process the air vent opening and the reinforcing bar insertion opening at the same time, thereby shortening the processing time. It leads to.

  In addition, the present invention extends to a method of constructing lower floor plate concrete below a steel flange connected to a corrugated steel plate constituting a PC box girder bridge. This construction method is connected to a corrugated steel plate and a corrugated steel plate. In a PC box girder bridge comprising at least a steel flange, a perforated rib and a stud gibber extending downward from the lower surface of the steel flange, and a lower floor board concrete in which the perfobond rib is embedded. A construction method for constructing lower floor board concrete below the formed steel flange, wherein the perforated rib has a first hole penetrating the reinforcing bar and a second hole opened in a boundary region between the steel flange. Assemble the mold under the steel flange connected to the corrugated steel sheet, fill the mold with fresh concrete, and do not vent the air upward through the second hole. Filled fresh concrete et mold inside is for applying a lower floor concrete is cured.

  According to the construction method of the present invention, the air pressed by the fresh concrete filled in the mold is moved through the second hole formed in the boundary region with the steel flange in the perforated rib, By discharging upward through the space between the steel flange and the formwork, it is possible to produce a highly durable PC box girder bridge while eliminating the occurrence of air and water pools below the steel flange. it can.

  In this construction method, an embodiment in which the first hole is an elongated hole extending downward from the boundary region with the steel flange and the second hole is included in the first hole is applied. As a result, the labor required for processing the hole is reduced, and the construction cost can be reduced.

  As can be understood from the above description, according to the PC box girder bridge of the present invention and the method of constructing the lower floor board concrete below the steel flange connected to the corrugated steel sheet, the air release during the construction of the lower floor board concrete is applied to the steel flange. Instead of opening a hole, an air vent hole (second hole) was opened in the boundary area with the steel flange of the perforated bond rib extending downward from the lower surface of the steel flange, so that the mold was filled. The air pressed by the fresh concrete is moved through the second hole formed in the boundary region between the steel flange in the perforbond rib and discharged upward through the space between the steel flange and the formwork. Thus, it is possible to manufacture a highly durable PC box girder bridge while eliminating the occurrence of air and water pools below the steel flange.

It is the perspective view which looked at the connection body of the corrugated steel plate and ribbed steel flange which comprises the PC box girder bridge of this invention from diagonally downward. (A), (b) is a side view of embodiment of a steel flange with a rib. It is the schematic diagram explaining the method of constructing lower floor board concrete under the steel flange connected to the corrugated steel plate. It is the schematic diagram which showed the connection structure of the manufactured steel flange connected to the corrugated steel plate, and lower floor board concrete. It is the longitudinal cross-sectional view which showed the conventional PC box girder bridge. FIG. 6 is an enlarged view of a VI part in FIG. 5, and is a perspective view of a corrugated steel plate-ribbed steel flange connection body constituting a PC box girder bridge as viewed obliquely from below. In the conventional PC box girder bridge, it is the schematic diagram explaining the method of constructing lower floor board concrete below the steel flange connected to the corrugated steel plate. It is the schematic diagram which showed the connection structure of the steel flange connected to the corrugated steel plate, and the lower floor board concrete manufactured in the conventional PC box girder bridge.

  Hereinafter, with reference to drawings, the method of constructing lower floor board concrete below the steel flange connected to the corrugated steel sheet of the present invention, and an embodiment of a PC box girder bridge will be described.

(Embodiment of a method of constructing lower floor board concrete below a steel flange connected to a corrugated steel sheet)
FIG. 1 is a perspective view of a connecting body of a corrugated steel plate and a ribbed steel flange constituting the PC box girder bridge of the present invention as viewed obliquely from below, and FIG. 3 is a lower side of the steel flange connected to the corrugated steel plate. It is the schematic diagram explaining the method of constructing floor board concrete.

  First, the configuration of the ribbed steel flange will be described with reference to FIG. As shown in the figure, a steel flange 3 with ribs applied by the construction method of the present invention is connected to a perforated rib 2 extending downward at the center of the lower surface of the steel flange 1, and stud gibber 4 on both sides thereof. Are connected and configured as a whole. A corrugated steel plate 5 is connected to the center position of the upper surface of the steel flange 1.

  The first hole 2a through which the reinforcing bar 6 indicated by a two-dot chain line is inserted is opened in the longitudinal direction of the rib in the vicinity of the center in the height direction of the perfobond rib 2 at an upper edge. Similarly, second holes 2b are formed in the boundary region with the steel flange at intervals in the longitudinal direction of the ribs.

  This 2nd hole 2b has a function as an air vent hole at the time of constructing lower floor board concrete.

  That is, in the conventional ribbed steel flange, an air vent hole is formed in the steel flange, whereas in the illustrated ribbed steel flange 3, an air vent hole is not opened in the steel flange. An air vent hole is opened in the boundary region between the bond rib 2 and the steel flange.

  Here, in FIGS. 2a and 2b, two embodiments of ribbed steel flanges are shown in side view.

  The ribbed steel flange 3 shown in FIG. 2a is a side view of the one described in FIG. 1, and in the perforated rib 2, a first hole 2a through which the reinforcing bar 6 is inserted, and an air vent The second holes 2b are processed individually. For example, when the height of the rib is 125 mm, the first hole 2a having a diameter of 50 mm is processed at a position about 70 mm from the upper edge of the rib (position slightly below the center position), and above the first hole 2a. An example in which a circular or vertically long second hole 2b corresponding to φ20 to 30 mm is processed on the upper edge of the rib can be given.

  On the other hand, in the ribbed steel flange 3A shown in FIG. 2b, a vertically long first hole 2a ′ is processed from the upper edge of the rib, and the first hole 2a ′ serves as a hole for inserting the reinforcing bar 6 and an air vent hole. It has become a thing. According to the ribbed steel flange 3A, it is not necessary to individually adjust the processing positions of the first hole and the second hole, and it is possible to simultaneously process the opening for air venting and the opening for reinforcing bar insertion. It leads to shortening of processing time.

  Next, with reference to FIG. 3, the method of constructing lower floor board concrete below the steel flange connected to the corrugated steel sheet will be described.

  The formwork K is assembled below the steel flange 1 constituting the ribbed steel flange 3 connected to the corrugated steel sheet 5, and fresh concrete C is filled into the formwork K.

  By the fresh concrete C filled in the mold K, the air in the mold K is pushed one side and through the second hole 2b opened in the boundary region with the steel flange of the perforated rib 2 ( Y direction), it is discharged upward through the space between the steel flange 1 and the formwork K. Therefore, the fresh concrete C can be filled in the mold K while eliminating the occurrence of air accumulation below the steel flange 1.

  And since the steel flange 1 to show in figure is not what the air vent hole was opened like the conventional steel flange with a rib, water approached the upper surface of lower floor board concrete through the air vent hole provided in the steel flange, The problem that a puddle occurs cannot arise.

  The construction method shown in FIG. 3 is connected to the corrugated steel plate 5 having no air pool on the upper surface of the constructed lower floor board concrete 7 and no water pool below the steel flange 1 as shown in FIG. A connection structure of the steel flange 1 and the lower floor board concrete 7 is formed.

  Even if the upper surface of the lower floor board concrete 7 sinks slightly during the hardening process of the fresh concrete and a gap is formed between the upper surface of the lower floor board concrete 7 and the steel flange 1, an air vent hole is opened in the steel flange 1. This gap will not cause a puddle.

  Although not shown in the drawings, a connecting structure of the steel flange 1 and the lower floor board concrete 7 connected to the corrugated steel sheet 5 shown in FIG. 4 is provided, and the upper floor board concrete is supported by the left and right corrugated steel sheets 5. PC box girder bridge is formed.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Steel flange, 2 ... Perfobond rib, 2a, 2a '... 1st hole, 2b ... 2nd hole, 3, 3A ... Steel flange with rib, 4 ... Stud gibber, 5 ... Corrugated steel plate, 6 ... Reinforcing bar, 7 ... Lower floor board concrete, K ... Formwork, C ... Fresh concrete

Claims (2)

A PC box comprising at least a corrugated steel sheet, a steel flange connected to the corrugated steel sheet, perforbond ribs and stud gibbles extending downward from the lower surface of the steel flange, and lower floor board concrete in which the perfobond ribs are embedded Girder bridge
The perforated rib is provided with a first hole penetrating the reinforcing bar and a second hole opened in a boundary region between the steel flange,
The second hole is a PC box girder bridge which is an air vent hole when constructing lower floor board concrete. A PC box comprising at least a corrugated steel sheet, a steel flange connected to the corrugated steel sheet, perforbond ribs and stud gibbles extending downward from the lower surface of the steel flange, and lower floor board concrete in which the perfobond ribs are embedded In the girder bridge, a construction method for constructing the lower floor board concrete below the steel flange connected to the corrugated steel sheet,
The perforated rib is provided with a first hole penetrating the reinforcing bar and a second hole opened in a boundary region between the steel flange,
Assemble the formwork below the steel flange connected to the corrugated steel sheet,
A steel flange connected to a corrugated steel plate that fills the formwork with fresh concrete, fills the formwork with fresh concrete while venting air upwards through the second hole, and hardens the lower floor board concrete The method of constructing the lower floor board concrete below.

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