JP2005139628A - Method for erecting bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the amount of used prestressing steel by easily controlling a tensile force of an outer cable by a simple outer cable structure, when a multi-span continuous bridge with the outer cable structure is erected by an incremental launching method. <P>SOLUTION: Cable inserting holes 30a are each pre-formed at upper edges of cross girders 30 which are arranged in positions of a pair of adjacent supporting points, and deflected locking parts 50 are pre-provided in two places at a lower edge of a main girder 20 between the supporting points. In incremental launching erection, the outer cable 40 is inserted into each of the cable inserting hole 30a, and tensioned so as to be linearly pre-arranged at the upper edge of the main girder 20. After the completion of the incremental launching erection, the tensile force of the outer cable 40 is released, and the outer cable 40 is deflected downward so as to be locked to each of the locking parts 50. After that, the outer cable 40 is re-tensioned. Thus, the outer cable 40, which is used in the erection, is diverted to a completed system, so that the amount of the used prestressing steel can be reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a bridge erection method in which a multi-span continuous bridge having an outer cable structure is erected by an extrusion method.

  Conventionally, as a method of erection of multi-span continuous bridges, a bridge body is manufactured for a predetermined length in a construction yard adjacent to the erection position, and then it is erected by pushing it toward the erection position by a predetermined length. An extrusion method is known for carrying out the process.

  In this extrusion method, with the progress of extrusion construction, a negative bending moment acts on the main girder at the fulcrum position, while a positive bending moment acts at the center between the fulcrum, and this is repeated alternately. It becomes. For this reason, conventionally, a device for resisting repetition of positive and negative bending moments is provided by arranging PC steel materials on both upper and lower edges of the main girder.

  On the other hand, in “Patent Document 1”, a vertical jack is arranged at the fulcrum position of the bridge body and the central part between the fulcrum, and the outer cable is alternately deflected in both the upper and lower directions according to the progress of the extrusion construction, The erection method that performs the stress control of the main girder is described.

  Further, in “Patent Document 2”, the outer cable is arranged in a straight line when the extrusion is installed, and after the extrusion installation is completed, the outer cable is arranged in both the upper and lower directions by a vertical jack arranged at the fulcrum position and the central portion between the fulcrums. A construction method for deflecting is described.

Japanese Examined Patent Publication No. 6-92643 JP-A-10-195817

  By adopting the erection method described in the above-mentioned "Patent Document 1" and "Patent Document 2", the PC steel material at the time of extrusion erection can be diverted to a completed system, so the amount of PC steel material used can be reduced However, these erection methods have the following problems.

  That is, it is extremely difficult to manage the tension of the outer cable with the installation methods described in the above-mentioned “Patent Document 1” and “Patent Document 2”, and there are a plurality of vertical guide rails, deflection racks, and vertical jacks. Since a pair is required, there is a problem that the outer cable structure becomes very complicated.

  The present invention has been made in view of such circumstances, and in a bridge erection method in which a multi-span continuous bridge having an outer cable structure is erected by an extrusion method, the tension of the outer cable is reduced by a simple outer cable structure. An object of the present invention is to provide a bridge erection method that can reduce the amount of PC steel used while allowing force management to be easily performed.

  The present invention is intended to achieve the above-mentioned object by performing tension, release of tension and re-tension of the outer cable by a predetermined method.

That is, the bridge erection method according to the present invention is:
In the bridge erection method to construct a multi-span continuous bridge having an outer cable structure by an extrusion method,
Cable insertion holes are respectively formed in the upper edge portions of the horizontal beams arranged at a pair of adjacent fulcrum positions, and a predetermined deflection locking portion is provided at the lower edge portion of the main beam between the fulcrum points of the both fulcrum positions. Set up
During extrusion installation, the outer cable is inserted through each cable insertion hole, and the outer cable is tensioned and arranged linearly at the upper edge of the main girder,
After completion of the extrusion construction, the tension of the outer cable is released, the outer cable is deflected downward and locked to the deflection locking portion, and then the outer cable is re-tensioned. It is.

  The above-mentioned “deflection locking portion” is not particularly limited as long as it is configured to be able to lock the outer cable from which the tension force is released while being deflected downward. Instead, it may be formed integrally with the main girder, or may be constituted by another member attached to the main girder. This “deflection locking portion” may be provided at one place between the fulcrums or at a plurality of places.

  As shown in the above configuration, in the bridge erection method according to the present invention, the cable insertion holes are respectively formed in the upper edge portions of the cross beams arranged at a pair of adjacent fulcrum positions, and between the fulcrum points. A predetermined deflection locking part is provided at the lower edge part of the main girder, and during extrusion construction, the outer cable is inserted into each cable insertion hole and the outer cable is tensioned to be linear at the upper edge part of the main girder. On the other hand, after the extrusion laying is completed, the tension of the outer cable is released and the outer cable is deflected downward and locked to the deflection locking portion, and then the outer cable is re-tensioned. Therefore, the following effects can be obtained.

  That is, since the external cable used at the time of erection can be diverted to a completed system, the amount of PC steel used can be reduced. At this time, since the fixing position of the outer cable is shared by the installation system and the completed system, it is not necessary to remove and reinsert the outer cable. For this reason, the rationalization and labor saving of construction can be achieved, and thereby the construction period can be shortened and the cost can be reduced.

  In addition, since the deflection of the outer cable is performed by the tension, release and re-tension of the outer cable, it is possible to easily manage the tension of the outer cable, and as in the conventional case, the vertical guide The outer cable structure can be greatly simplified as compared with the case where the outer cable is deflected by using a plurality of sets of rails, deflection racks and vertical jacks.

  As described above, according to the present invention, in the bridge laying method in which the multi-span continuous bridge having the outer cable structure is laid by the extrusion method, the tension control of the outer cable can be easily performed by the simple outer cable structure. In this way, the amount of PC steel used can be reduced.

  In the above configuration, when the outer cable is tensioned, shim adjustment is performed at the fulcrum position so that the lower deflection allowance of the outer cable is secured in advance. Etc., so that workability can be improved. This shim adjustment may be performed at the fulcrum positions on both sides, or may be performed at the fulcrum positions on one side.

  In the above configuration, the cable insertion hole is formed so as to expand downward in the direction between the fulcrums, and a special deflection pipe that extends downward in the direction between the fulcrums is attached to the cable insertion hole. By doing so, the outer cable can be deflected downward without difficulty, thereby effectively suppressing the concentration of stress in the outer cable and the damage of the outer cable.

  Furthermore, in the above configuration, if the cable insertion hole is formed so as to bend downward in the direction opposite to the fulcrum, the fixing position is lowered below the linearly arranged outer cable. Therefore, the fixing structure can be made difficult to interfere with the fixing structure of the outer cable disposed in the adjacent span portion. As a result, it is possible to easily establish the outer cable structure in each span portion by arranging the outer cables slightly adjacent to each other in the direction perpendicular to the bridge axis between adjacent span portions.

  Further, in the above configuration, if an overhanging wall is formed between the fulcrum to protrude from the web of the main girder to the side, and the deflection locking portion is formed on the lower end surface of the overhanging wall, the outer cable is connected. Sufficient support strength can be ensured with respect to the load acting on the deflection lock when re-tensioned.

  At that time, if the portion near the lower end surface of the overhanging wall is formed to be thicker than the other portions of the overhanging wall, the supporting strength against the load when the outer cable is re-tensioned can be further increased. .

  At that time, if the deflection locking portion is formed by forming an inverted U-shaped groove on the lower end surface of the overhanging wall and attaching a half-diabatic tube to the inverted U-shaped groove, When the cable is re-tensioned, the outer cable can be smoothly slid, so that it is possible to more effectively suppress stress concentration and damage to the outer cable.

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

  FIG. 1 is a process diagram showing an outline of a bridge erection method according to an embodiment of the present invention, and is a diagram showing a side cross section along a bridge axis direction of a multi-span continuous bridge to be erected. FIG. 2 is a diagram showing the multi-span continuous bridge in a cross-section perpendicular to the bridge axis, in which FIG. 2 (a) is a sectional view taken along the line IIa-IIa in FIG. 1, and FIG. A sectional view taken along line -IIb, and FIG. 10C is a sectional view taken along line IIc-IIc in FIG. 3 to 5 are process diagrams showing in detail the erection method according to this embodiment, and are enlarged views of the main part of FIG. Further, FIG. 6 is a detailed view of a VI part in FIG. 3A, and FIG. 7 is a detailed view of a VII part in FIG.

  As shown in these drawings, the multi-span continuous bridge to be installed in this embodiment has a bridge body 10 arranged in a box-shaped cross-section and extending in the bridge axis direction at each fulcrum position. And has an outer cable structure.

  The main girder 20 is formed in a box girder shape by an upper floor slab 22 and a lower floor slab 24 made of prestressed concrete, and a pair of left and right webs 26 made of corrugated steel plates. On the other hand, the upper part of the cross beam 30 extends in the direction perpendicular to the bridge axis with an inverted trapezoidal cross section along the upper floor slab 22. In the outer cable structure, a pair of left and right outer cables 40 are arranged for each span portion in the box-shaped cross section of the main girder 20.

  In the completed system, both ends of the outer cable 40 are inserted into the cable insertion holes 30a formed in the upper edge portions of the pair of cross beams 30 adjacent in the bridge axis direction. In the state where the intermediate portion is deflected downward, the center portion between the fulcrums of the main girder 20 is engaged with a pair of deflection locking portions 50 provided at a predetermined interval in the bridge axis direction. It has been stopped.

  Each cable insertion hole 30a is formed so as to expand downward in the direction between the fulcrums, and is formed so as to curve downward in a direction opposite to the interval between the fulcrums. The cable insertion hole 30a is fitted with a special deflection pipe 60 that expands downward in the direction between the fulcrums. The downward expansion angle of the special deflection tube 60 is set to a value slightly larger than the downward deflection angle when the outer cable 40 is re-tensioned.

  Each deflection locking portion 50 is configured such that a half Diabo tube 52 is attached to an inverted U-shaped groove 28a formed on the lower end surface of the overhanging wall 28 projecting inward from the web 26. The half Diaboro tube 52 is formed to be bent downward with a predetermined curvature so that the outer cable 40 slides sufficiently smoothly when the outer cable 40 is re-tensioned. The overhanging wall 28 has a lower end surface vicinity portion 28b formed thicker than other portions of the overhanging wall 28.

  In addition, the deflection | deviation latching part 50 is provided in the position near the web 26 rather than the cable penetration hole 30a regarding the bridge axis orthogonal direction. Correspondingly, the cable insertion hole 30a and the special deflection tube 60 are formed so as to expand in a direction inclined toward the web 26 with respect to the vertically downward direction.

  Construction of the multi-span continuous bridge is performed by an extrusion method as shown in FIG.

  That is, as shown in FIG. 6A, after a part of the bridge body 10 is manufactured for one span length in the construction yard 104 adjacent to the erection position 102, as shown in FIG. 10 is pushed out by one span length toward the installation position 102 together with the hand girder 112 attached to the tip thereof, and then the above operation is repeated several times as shown in FIGS. By repeating this, the bridge body 10 is erected. The extrusion at the time of erection is performed by a plurality of extrusion devices 114 arranged on the construction yard 104 and the upper end surfaces of the abutment 12 and the pier 14.

  In the extrusion erection process, at the time of extrusion erection, both ends of the outer cable 40 are inserted into the cable insertion holes 30a as shown in FIG. It is arranged in a straight line at the edge. Then, after the extrusion is completed, the tension of the outer cable 40 is released as shown in FIG. 5B, and the outer cable 40 is deflected downward as shown in FIG. After locking to the locking portion 50, the outer cable 40 is re-tensioned.

  The details of the tension, release of tension, and re-tension of the outer cable 40 performed in the extrusion laying process are as follows.

  The tension of the outer cable 40 in the first stage is performed in the construction yard 104 before the bridge body 10 is pushed out.

  At this time, as shown in FIGS. 3A and 6, at one fulcrum position, the outer cable 40 is in a state where a predetermined number of shim plates 62 are interposed in the fixing recess 30 b formed in the cross beam 30. The fixing tool 64 and the jack 116 are attached to the end portions, and the outer cable 40 is tensioned by the jack 116, thereby performing shim adjustment for securing a downward deflection margin of the outer cable 40 in advance. At this time, at the other fulcrum position, the end portion of the outer cable 40 is directly fixed by the fixing tool 64 in advance in the fixing concave portion 30 b formed in the cross beam 30.

  And as shown in FIG.3 (b), after removing the jack 116 once, the bridge body 10 is extruded in this state.

  The tension release of the outer cable 40 in the next stage is performed as follows.

  That is, as shown in FIG. 4C, at one fulcrum position, a portal-shaped ram chair 118 is attached to the end of the outer cable 40 so as to cover the shim plate 62 and the fixing tool 64. Is brought into contact with the fixing recess 30 b of the cross beam 30, and then a jack 116 is attached to the end of the outer cable 40, and the fixing tool 64 is loosened by the jack 116 to release the tension of the outer cable 40.

  And as shown in the figure (d), by pulling out the shim plate 62 little by little, the outer cable 40 is drawn out in the direction between the fulcrums. Thereafter, the ram chair 118 is removed with the jack 116 attached. At that time, the end of the outer cable 40 is temporarily fixed by the fixing tool 64.

  The re-tensioning of the outer cable 40 at the final stage is performed as follows.

  That is, as shown in FIGS. 5 (e) and 7, after the outer cable 40 released from the tension force is deflected downward between the fulcrums and locked to the deflection locking portions 50, at one fulcrum position, The outer cable 40 is re-tensioned by the jack 116 that is still attached to the end of the outer cable 40, and the end of the outer cable 40 is fixed by the fixing tool 64 in this state.

  And after removing the jack 116 as shown to the same figure (f), the outer cable structure is completed by cutting off the unnecessary part of the edge part of the outer cable 40. FIG.

  As described above in detail, the bridge erection method according to the present embodiment has the cable insertion holes 30a formed in the upper edge portions of the cross beams 30 arranged at the pair of adjacent fulcrum positions, respectively. Deflection locking portions 50 are provided at two locations on the lower edge of the main girder 20 between the fulcrums. When the extrusion is installed, the outer cable 40 is inserted into each cable insertion hole 30a and the outer cable 40 is tensioned to form the main girder. 20 is arranged in a straight line at the upper edge portion, but after completion of the extrusion construction, the tension of the outer cable 40 is released and the outer cable 40 is deflected downward to be locked to each deflection locking portion 50. After that, since the outer cable 40 is re-tensioned, the following effects can be obtained.

  That is, since the outer cable 40 used at the time of erection can be diverted to a completed system, the amount of PC steel used can be reduced. At this time, since the fixing position of the outer cable 40 is shared by the installation system and the completed system, the removal and reinsertion of the outer cable 40 can be made unnecessary. For this reason, the rationalization and labor saving of construction can be achieved, and thereby the construction period can be shortened and the cost can be reduced.

  Moreover, since the deflection of the outer cable 40 is performed by the tension, release of tension, and re-tensioning of the outer cable 40, the tension force of the outer cable 40 can be easily managed, as in the conventional case. As compared with the case where the outer cable is deflected by using a plurality of sets of vertical guide rails, deflection mounts and vertical jacks, the outer cable structure can be greatly simplified.

  As described above, according to the present embodiment, it is possible to easily manage the tension of the outer cable 40 with a simple outer cable structure, and it is possible to reduce the amount of PC steel used.

  In addition, in the present embodiment, when the outer cable 40 is tensioned, shim adjustment is performed at one fulcrum position, and the lower deflection allowance of the outer cable 40 is secured in advance. The tension of the outer cable 40 can be easily released by using the ram chair 118, thereby improving workability.

  In the present embodiment, the cable insertion hole 30a is formed so as to expand downward in the direction between the fulcrums, and the special deflection tube 60 that extends downward in the cable insertion hole 30a in the direction between the fulcrums. Since the outer cable 40 can be deflected downward without difficulty, stress concentration on the outer cable 40 or damage to the outer cable 40 can be effectively prevented. Can be suppressed.

  Further, in the present embodiment, the cable insertion hole 30a is formed so as to bend downward in the direction opposite to the fulcrum, so that the outer cable 40 arranged in a straight line is provided with the cable insertion hole 30a. On the other hand, the fixing position can be displaced downward. Therefore, the fixing structure of the outer cable 40 can be made difficult to interfere with the fixing structure of the outer cable 40 disposed in the adjacent span portion. As a result, it is possible to easily establish the outer cable structure in each span portion only by arranging the outer cables 40 slightly adjacent to each other in the direction perpendicular to the bridge axis between adjacent span portions.

  In the present embodiment, an overhanging wall 28 that projects inward from the web 26 of the main girder 20 is formed between the fulcrums, and the deflection locking portion 50 is formed on the lower end surface of the overhanging wall 28. Therefore, sufficient support strength can be ensured with respect to the load acting on the deflection locking portion 50 when the outer cable 40 is re-tensioned.

  In addition, at that time, the portion 28b near the lower end surface of the overhanging wall 28 is formed to be thicker than the other portions of the overhanging wall, so that the support strength against the load when the outer cable 40 is re-tensioned Can be further enhanced.

  At that time, the deflection locking portion 50 is configured by forming the inverted U-shaped groove 28a on the lower end surface of the overhanging wall 28 and attaching the half-diabatic tube 52 to the inverted U-shaped groove 28a. Therefore, when the outer cable 40 is re-tensioned, the outer cable 40 can be smoothly slid, and thereby, it is more effective that stress concentration and damage occur in the outer cable 40. Can be suppressed.

  By the way, in the said embodiment, although it demonstrated as what has only the external cable 40 as an external cable structure, external cables other than the external cable 40 are linearly formed in the upper edge part and lower edge part of the main girder 20 at the time of extrusion construction. Or may be arranged in an appropriately deflected state, and after completion of the extrusion construction, an external cable other than the external cable 40 is additionally arranged in the same arrangement as the external cable 40. You may do it.

  In the above embodiment, it has been described that the deflection locking portions 50 are provided at two locations on the lower edge portion of the main beam 20 between the fulcrums, but instead of this, at one location or three or more locations. It is also possible to provide the deflection locking part 50.

  Moreover, in the said embodiment, although demonstrated as what the main girder 20 of the multi span continuous bridge used as construction object has a pair of webs 26 on either side, also when it has three or more webs, The same effect as the embodiment can be obtained.

  Furthermore, in the said embodiment, although demonstrated as what the main girder 20 of the multi span continuous bridge used as construction object was formed in the box girder shape, even when it has a main girder structure other than this, the said embodiment The same effect can be obtained.

  Moreover, in the said embodiment, although the case where the multi span continuous bridge used as construction object was what is called a corrugated steel web bridge, it was the same effect as the said embodiment also when it is a normal prestressed concrete bridge etc. Can be obtained.

It is process drawing which shows the outline | summary of the construction method of the bridge which concerns on one Embodiment of this invention, Comprising: The figure shown by the side cross section along the bridge axis direction of the multi span continuous bridge used as construction object FIG. 2 is a view showing the multi-span continuous bridge in a cross-section perpendicular to the bridge axis, in which FIG. 1 (a) is a cross-sectional view taken along the line IIa-IIa in FIG. 1, and FIG. (C) is a sectional view taken along line IIc-IIc in FIG. Process drawing which shows the erection method concerning the said embodiment in detail (the 1) Process drawing which shows the erection method concerning the said embodiment in detail (the 2) Process drawing which shows the erection method concerning the said embodiment in detail (the 3) Detailed view of VI part in Fig. 3 (a) Detail view of part VII in Fig. 5 (e) Process drawing which shows the outline | summary of the extrusion method used with the construction method which concerns on the said embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bridge body 12 Abutment 14 Bridge pier 20 Main girder 22 Upper floor slab 24 Lower floor slab 26 Web 28 Overhanging wall 28a Reverse U-shaped groove 28b Lower end surface vicinity 30 Horizontal girder 30a Cable insertion hole 30b Fixing concave part 40 Outer cable 50 Deflection lock Part 52 Half Diaboro pipe 60 Special deflection pipe 62 Shim plate 64 Fixing tool 102 Installation position 104 Construction yard 112 Hand girder 114 Extruding device 116 Jack 118 Ram chair

Claims (7)

In the bridge erection method to construct a multi-span continuous bridge having an outer cable structure by an extrusion method,
Cable insertion holes are respectively formed in the upper edge portions of the horizontal beams arranged at a pair of adjacent fulcrum positions, and a predetermined deflection locking portion is formed on the lower edge portion of the main beam between the fulcrum points of the two fulcrum positions. Set up
During extrusion installation, the outer cable is inserted through the cable insertion holes, and the outer cable is tensioned and arranged linearly at the upper edge of the main girder,
A bridge characterized by releasing the tension of the outer cable after completion of the extrusion construction and deflecting the outer cable downward and locking it to the deflection locking portion, and then re-tensioning the outer cable. Construction method.   The method of laying a bridge according to claim 1, wherein when the outer cable is tensioned, shim adjustment is performed at the fulcrum position, and a downward deflection allowance of the outer cable is secured in advance.   The cable insertion hole is formed so as to expand downward in the direction between the fulcrums, and a special deflection pipe extending downward in the direction between the fulcrums is attached to the cable insertion hole. The method for laying a bridge according to claim 1 or 2.   The bridge laying method according to any one of claims 1 to 3, wherein the cable insertion hole is formed so as to bend downward in a direction opposite to the fulcrum.   2. A protruding wall that protrudes laterally from the web of the main girder is formed between the fulcrums, and the deflection locking portion is formed on the lower end surface of the protruding wall. The bridge construction method according to any one of? 4.   6. The method of laying a bridge according to claim 5, wherein a portion near the lower end surface of the overhanging wall is formed thicker than other portions of the overhanging wall.   6. The deflection locking portion is formed by forming an inverted U-shaped groove on the lower end surface of the overhanging wall and attaching a half-diabatic tube to the inverted U-shaped groove. Or the bridge construction method of 6.

Images