JP2005220593A - Pc steel anchoring method and prestressed concrete bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PC steel anchoring method for safely and economically anchoring PC steels on a floor slab without forming anchorage projections on the upper surface of the floor slab, and to provide a prestressed concrete bridge. <P>SOLUTION: When a lower floor slab 5 is formed, depressions 25 are formed on the upper surface 15 of the lower floor slab, thickened portions 19 are formed on the lower surface 17 of the same, and sheaths 27 are formed therein. Each sheath 27 is a hole penetrating from the side surface 20 of one of the depressions 25 to the side surface 20 of the other depression 25. Then the PC steel 13 is inserted from the side of the upper surface 15 of the lower floor slab 5 into the sheath 27 to be strained. Then by using an anchorage device 21 arranged near a boundary between the depression 25 and the sheath 27, the PC steel 13 is anchored to the lower floor slab 5. Further fillers 29 are set in the depressions 25, and the surface of the lower floor slab 5 is smoothed, to thereby complete the construction of an anchorage portion 23. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a PC steel fixing method and a prestressed concrete bridge.

  Conventionally, PC steel materials for prestressed concrete bridges are on the upper edge side of the main girder for negative bending moments that predominate near the column heads, and for main bending beams for positive bending moments that predominate near the center of the span. It is arranged on the lower edge side. The PC steel material on the lower edge side is usually fixed by fixing protrusions manufactured on the upper surface of the lower floor slab or on the inside of the web (see, for example, Patent Document 1).

JP 2003-082614 A

  When adopting a double deck section for rationalization of the bridge structure in concrete bridges, it is desirable to make the main girder structure truss or open structure in order to reduce the weight of the main girder and consider the landscape. In this case, since the web is not continuous, the PC steel material on the lower edge side cannot be fixed to the web. Therefore, fixing protrusions are provided on the upper surface or the lower surface of the lower floor slab, and the PC steel material on the lower edge side is fixed to the lower floor slab.

  However, in the double deck section, the upper surface of the lower floor slab is the road surface. If fixing protrusions are provided on the upper surface of the lower floor slab, the unevenness adjustment of the upper surface of the floor slab must be made very thick, which is uneconomical. . In addition, when a fixing protrusion is provided on the lower surface of the lower floor slab, a work floor or the like by a suspension scaffold is installed to perform insertion / tensioning work of the PC steel material, which is often difficult from the viewpoint of safety and economy.

  1st invention has arrange | positioned in the said process which forms the floor slab which has a sheath and the space provided in the edge part of the said sheath, inserts and tensions PC steel materials in the said sheath, A PC steel material fixing method comprising: a step of fixing the PC steel material to the floor slab using a fixing tool; and a step of installing a filler in the space.

  The space is a recess provided on the upper surface of the floor slab or an opening that penetrates the floor slab vertically. Of the floor slab, a thicker portion is provided on the portion where the space is provided and the lower surface around the space as necessary. The floor slab is, for example, a lower deck of a double deck bridge. Concrete or the like is used for the filler.

  In 1st invention, when inserting and tensioning PC steel materials in the sheath provided in the floor slab, spaces, such as a recessed part provided in the sheath edge part and an opening part, are used. And after fixing PC steel material to a floor slab using the fixing tool arrange | positioned in space, a filler is installed in space.

A second invention is a prestressed concrete bridge in which a PC steel material is installed using the PC steel material fixing method of the first invention.
In the second invention, the PC steel material is fixed to the lower floor slab of the double deck bridge by the fixing method of the PC steel material of the first invention.

  The PC steel material fixing method and the prestressed concrete bridge of the present invention can fix the PC steel material to the floor slab safely and economically without providing the fixing protrusion on the floor slab upper surface.

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. 1 is a cross-sectional view of the prestressed concrete bridge 1 cut along a vertical plane in the direction of the bridge axis, and FIG. 2 is a perspective view of a cross section of the prestressed concrete bridge 1 cut along a vertical plane in the direction perpendicular to the bridge axis.

  As shown in FIGS. 1 and 2, the prestressed concrete bridge 1 includes an upper floor slab 3, a lower floor slab 5, a diagonal member 7, a road surface 9, a road surface 11, a PC steel material 13, a fixing portion 23, and the like. The upper floor slab 3 and the lower floor slab 5 are concrete. The diagonal member 7 is a steel pipe or the like. The PC steel material 13 is a PC steel rod, a PC steel strand or the like. The diagonal member 7 connects the upper floor slab 3 and the lower floor slab 5. The road surface 9 is provided on the upper surface of the upper floor slab 3, and the road surface 11 is provided on the upper surface 15 of the lower floor slab 5.

  3 is a cross-sectional view of the fixing unit 23 cut along a vertical plane in the bridge axis direction, and FIG. 4 is a cross-sectional view of the fixing unit 23 cut along a vertical plane perpendicular to the bridge axis direction. 3 is an enlarged view of the vicinity of the fixing unit 23 in FIG. 1, and FIG. 4 is a cross-sectional view taken along line AA in FIG.

  In order to introduce prestress to the lower floor slab 5, when forming the lower floor slab 5, as shown in FIGS. 1 to 3, as shown in FIGS. A sheath 27 is provided.

  The concave portion 25 is a box opening portion in which the upper surface 15 of the lower floor slab 5 is opened. The recesses 25 are provided at, for example, four locations within the span. As shown in FIG. 1, the breakdown of the four places is two places on the same line in the bridge axis direction, and two places on the same line in the direction perpendicular to the bridge axis as shown in FIG. The increased thickness portion 19 is obtained by increasing the thickness of the lower floor slab 5 toward the lower surface 17 in order to secure the depth 24 of the recess 25, and is formed of concrete integrally with the lower floor slab 5.

  As shown in FIG. 3, the sheath 27 is a hole for installing the PC steel material 13, and includes a side surface 20 of a certain recess 25 and a side surface 20 of another recess 25 provided on the same line in the bridge axis direction. It is formed so as to penetrate between them. As shown in FIG. 2, a plurality of sheaths 27 are arranged in parallel in the lower floor slab 5.

  After the lower floor slab 5 is formed as shown in FIG. 2, the PC steel material 13 is inserted into the sheath 27 from the upper surface 15 side of the lower floor slab 5 with the recess 25 as a working space as shown in FIG. I'm nervous. And the PC steel material 13 is fixed with the fixing tool 21 installed in the boundary part vicinity of the sheath 27 and the recessed part 25. FIG. Further, as shown in FIGS. 1 and 4, the fixing portion 23 is completed by filling the concave portion 25 with a filler 29. The filler 29 is, for example, concrete.

  After the fixing unit 23 is completed, the road surface 11 is formed on the upper surface 15 of the lower floor slab 5 as shown in FIG. In addition, the prestressed concrete bridge 1 is completed by appropriately forming the diagonal members 7, the upper floor slab 3, the road surface 9 and the like.

  As described above, in the first embodiment, after the fixing portion 23 is formed, there is no fixing protrusion on the upper surface 15 of the lower floor slab 5, and the road surface 11 can be constructed without performing unnecessarily uneven adjustment. This is expected to improve the economics associated with the weight reduction of the entire bridge. Further, since the increased thickness portion 19 is integrally formed with the lower floor slab 5, the color difference of the concrete hardly occurs.

  When the fixing unit 23 is constructed, the PC steel material 13 can be inserted, tensioned, and fixed from the upper surface 15 side of the lower floor slab 5 using the recess 25 provided on the upper surface 15 of the lower floor slab 5. Further, since the thicker portion 19 is provided on the lower surface 17 of the lower floor slab 5 and the lower surface of the recess 25 is not open, when the PC steel material 13 is inserted, tensioned or fixed from above the lower floor slab 5, The safety below the plate 5 is ensured. For this reason, it is superior in safety, workability, and economy as compared to the case where a work floor is separately installed and constructed.

  It should be noted that the installation position and number of fixing units 23 and the number of PC steel materials 13 to be fixed in the fixing unit 23 may not be those described above. Further, the shape of the concave portion 25 and the increased thickness portion 19 for forming the fixing portion 23 is not limited to that shown in FIG. 3, but is set according to the size and shape of the fixing tool.

  FIG. 5 is a cross-sectional view of the other fixing portion 23a cut along a vertical plane in the bridge axis direction. In the fixing unit 23 a shown in FIG. 5, a fixing tool 21 a larger than the fixing tool 21 is used. The cross-sectional shape of the fixing unit 23a cut along BB shown in FIG. 5 is the same as the cross-section of the fixing unit 23 shown in FIG.

  The concave portion 25a, the increased thickness portion 19a, the sheath 27a, the PC steel material 13a, the fixing tool 21a, and the filler 29a of the fixing portion 23a are the same as the concave portion 25, the increased thickness portion 19, the sheath 27, and the PC steel material 13 of the fixing portion 23 shown in FIG. These correspond to the fixing device 21 and the filler 29. The recess 25a and the increased thickness portion 19a are formed such that the depth 24a is deeper than the depth 24 of the recess 25.

  In the fixing portion 23a, an increased thickness portion 33 for installing the fixing tool 21a and the sheath 27a is provided on the lower surface 17 of the lower floor slab 5 in succession to the increased thickness portion 19a for forming the recess 25a. The sheath 27a is not linear like the sheath 27 shown in FIGS. 1 and 3, but is disposed so that a portion in the increased thickness portion 33 is inclined downward. The increased thickness portion 19 a and the increased thickness portion 33 are driven integrally with the lower floor slab 5. At the same time, the lower floor slab 5 is formed with a recess 25a and a sheath 27a.

  In the fixing unit 23a, as in the fixing unit 23, the PC steel material 13a is inserted into the inside of the sheath 27a from the upper surface 15 side of the lower floor slab 5 using the concave portion 25a as a work space, and is tensioned. And the PC steel material 13a is fixed with the fixing tool 21a installed in the boundary part vicinity of the sheath 27a and the recessed part 25a. Further, as shown in FIGS. 4 and 5, the recess 25a is filled with a filler 29a.

  Even when the fixing unit 23a is used, there is no fixing protrusion on the upper surface 15 of the lower floor slab 5, and the road surface 11 can be constructed without performing unnecessarily uneven adjustment. Further, since the increased thickness portion 19a and the increased thickness portion 33 are integrally formed with the lower floor slab 5, the color difference of the concrete is unlikely to occur. Further, since the thicker portion 19a is provided on the lower surface 17 of the lower floor slab 5 and the lower surface of the recess 25a is not open, when the insertion, tension and fixing of the PC steel material 13a is performed from above the lower floor slab 5, the lower floor The safety below the plate 5 is ensured.

  Next, a second embodiment will be described. FIG. 6 shows a perspective view of a cross section of the prestressed concrete bridge 31 cut along a vertical plane perpendicular to the bridge axis.

  A prestressed concrete bridge 31 shown in FIG. 6 is similar to the prestressed concrete bridge 1 shown in FIG. 1 and the like, such as an upper floor slab 3, a lower floor slab 5, an oblique member 7, a road surface 9, a road surface 11, a PC steel material 13, a fixing portion 23b, and the like. Consists of In the prestressed concrete bridge 31, the structure of the fixing part 23b is different from the fixing part 23 of the prestressed concrete bridge 1.

  7 is a cross-sectional view of the fixing portion 23b cut along a vertical plane in the bridge axis direction, and FIG. 8 is a cross-sectional view of the fixing portion 23b cut along a vertical plane perpendicular to the bridge axis direction. 8 is a cross-sectional view taken along the line CC of FIG.

  In order to introduce prestress into the lower floor slab 5, when the lower floor slab 5 is formed, as shown in FIGS. 7 and 8, an opening 35 and a sheath 27 are provided. The opening portion 35 corresponds to the concave portion 25 of the fixing portion 23 shown in FIG. 3 and is a box opening portion that vertically penetrates the lower floor slab 5. For example, the openings 35 are provided at four locations in the span, similarly to the recess 25 of the first embodiment.

  As shown in FIG. 7, the sheath 27 is provided so as to penetrate between a side surface 20b of a certain opening 35 and a side surface 20b of another opening 35 provided on the same line in the bridge axis direction. As shown in FIG. 6, a plurality of sheaths 27 are formed in parallel in the lower floor slab 5.

  After the lower floor slab 5 is formed as shown in FIG. 6, the PC steel material 13 is inserted into the sheath 27 from the upper surface 15 side of the lower floor slab 5 with the opening 35 as a working space as shown in FIG. And tense. And the PC steel material 13 is fixed with the fixing tool 21 installed in the boundary part vicinity of the sheath 27 and the recessed part 25. FIG. Furthermore, as shown in FIG. 8, the opening portion 35 is filled with a filler 29b to complete the fixing portion 23b.

  After the fixing portion 23b is completed, the road surface 11 is formed on the upper surface 15 of the lower floor slab 5 in the same manner as the prestressed concrete bridge 1 shown in FIG. Also, the prestressed concrete bridge 31 is completed by appropriately forming the diagonal members 7, the upper floor slab 3, the road surface 9 and the like.

  As described above, in the second embodiment, after the fixing portion 23b is formed, there is no fixing protrusion on the upper surface 15 of the lower floor slab 5, and the road surface 11 can be constructed without performing unnecessarily uneven adjustment. This is expected to improve the economics associated with the weight reduction of the entire bridge. Moreover, at the time of construction, the PC steel material 13 can be inserted, tensioned, and fixed from the upper surface 15 side of the lower floor slab 5 using the opening 35 penetrating the lower floor slab 5 up and down. For this reason, it is superior in safety, workability, and economy as compared with the case where a work floor is separately installed.

  Note that the installation position and the number of fixing units 23b and the number of PC steel materials 13 to be fixed in the fixing unit 23b may not be those described above. Further, depending on the size and shape of the fixing tool, a thicker portion may be provided on the lower surface 17 of the lower floor slab 5.

  FIG. 9 is a cross-sectional view of another fixing unit 23c cut along a vertical plane in the bridge axis direction, and FIG. 10 is a cross-sectional view of the fixing unit 23c cut along a vertical plane perpendicular to the bridge axis direction. 10 is a cross-sectional view taken along the line DD of FIG. In the fixing unit 23c shown in FIGS. 9 and 10, a fixing tool 21a larger than the fixing tool 21 is used.

  The opening 35a, the sheath 27a, the PC steel material 13a, the fixing tool 21a, and the filler 29a of the fixing portion 23c are the same as the opening 35, the sheath 27, the PC steel material 13, the fixing tool 21, and the filling material 29a shown in FIGS. It corresponds to the filler 29. The opening 35a is a box opening that penetrates the lower floor slab 5 up and down.

  In the fixing unit 23 c, an additional thick portion 33 a for installing the sheath 27 a and the fixing tool 21 a is provided on the lower surface 17 around the opening 35 a of the lower floor slab 5. The sheath 27a is not linear like the sheath 27 shown in FIGS. 1 and 3, but is disposed so that a portion in the increased thickness portion 33a is inclined downward. The increased thickness portion 33a is driven integrally with the lower floor slab 5. At the same time, an opening 35 a and a sheath 27 a are formed in the lower floor slab 5.

  In the fixing unit 23c, similarly to the fixing unit 23b, the PC steel material 13a is inserted into the inside of the sheath 27a from the upper surface 15 side of the lower floor slab 5 with the opening 35a as a work space, and is tensioned. Then, the PC steel material 13a is fixed by the fixing tool 21a installed near the boundary between the sheath 27a and the opening 35a. Further, as shown in FIGS. 9 and 10, the opening 35a is filled with a filler 29c.

  Even when the fixing unit 23c is used, there is no fixing protrusion on the upper surface 15 of the lower floor slab 5, and the road surface 11 can be constructed without performing unnecessarily uneven adjustment. Further, at the time of construction, the PC steel material 13a can be inserted, tensioned, and fixed from the lower floor slab 5 using the opening 35a penetrating the lower floor slab 5 up and down.

  The preferred embodiments of the PC steel fixing method and prestressed concrete bridge according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

Sectional view of prestressed concrete bridge 1 cut along a vertical plane in the direction of the bridge axis Perspective view of cross section of prestressed concrete bridge 1 cut along a vertical plane perpendicular to the bridge axis Sectional view of the fixing unit 23 cut along a vertical plane in the bridge axis direction Sectional view in which fixing unit 23 is cut along a vertical plane perpendicular to the bridge axis Sectional drawing which cut | disconnected other fixing | fixed part 23a with the perpendicular | vertical surface of a bridge axis direction Cross-sectional perspective view of prestressed concrete bridge 31 cut along a vertical plane perpendicular to the bridge axis Sectional drawing which cut | disconnected the fixing | fixed part 23b with the vertical surface of the bridge axis direction Sectional drawing which cut | disconnected the fixing | fixed part 23b with the perpendicular | vertical surface of a bridge axis perpendicular direction Sectional drawing which cut | disconnected other fixing | fixed part 23c by the perpendicular surface of a bridge axis direction Sectional drawing which cut | disconnected other fixing | fixed part 23b by the perpendicular surface of a bridge axis perpendicular direction

Explanation of symbols

1, 31 ......... Prestressed concrete bridge 3 ... Upper floor slab 5 ... ... Lower floor slab 13, 13a ... ... PC steel 17 ... ... Lower surface 19, 19a, 33, 33a ... ... Increased thickness part 21, 21a... Fixing tools 23, 23a, 23b, 23c... Fixing portions 25, 25a. Aperture

Claims (6)

Forming a floor slab having a sheath and a space provided at an end of the sheath;
Inserting and tensioning the PC steel into the sheath;
Fixing the PC steel material to the floor slab using a fixing tool arranged in the space;
Installing a filler in the space;
The fixing method of PC steel materials characterized by comprising.   The method for fixing a PC steel material according to claim 1, wherein the space is a recess provided on an upper surface of the floor slab.   The method for fixing a PC steel material according to claim 1, wherein the space is an opening that vertically penetrates the floor slab.   The method for fixing a PC steel material according to claim 1, wherein an increased thickness portion is provided on a lower surface of the floor slab.   The method for fixing PC steel according to claim 1, wherein the floor slab is a lower floor slab of a double deck bridge.   A prestressed concrete bridge in which a PC steel material is installed by using the fixing method for a PC steel material according to any one of claims 1 to 5.

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