Construction method for pier extension stages and piers

Abstract

To provide a method for constructing a pier extension stage and pier that allows the installation position of a heavy machinery crane to be displaced toward the extended side of the existing superstructure during construction. [Solution] A detachable cantilever stage is used, which comprises an auxiliary support frame that can extend outwards from the front end of the existing superstructure in the direction of the bridge axis, and a plurality of auxiliary covering plates laid on the upper surface of the auxiliary support frame. The cantilever stage is extended to the front end of the existing superstructure with the end face of the auxiliary girder of the auxiliary support frame in contact with the front end of the main girder of the existing superstructure, and the superstructure for the next span is constructed using a heavy equipment crane that is set up straddling the existing superstructure and the cantilever stage.

Description

Technical Field

[0001] The present invention relates to a protruding stage for a pier and a method for constructing a pier.

Background Art

[0002] Conventionally, to construct a pier, there are steps of driving support piles at intervals, erecting main girders in the bridge axis direction between the heads of the support piles, laying covering plates on the upper surfaces of adjacent main girders, and repeating these steps in span units to extend the pier (Patent Document 1). These series of operations are performed using a heavy crane placed on the upper surface of an existing pier.

[0003] Also, a construction method has been proposed in which an overhanging unit having a length of one span fabricated on-site is used, and the pier is extended while extending the overhanging unit from the existing superstructure in a cantilever structure. In this construction method, since the overhanging unit has a cantilever structure with respect to the existing superstructure, means for horizontally supporting the overhanging unit is required. As means for supporting the overhanging unit, it is supported by a suspension rope stretched obliquely between the head of a column erected at the end of the existing superstructure and the overhanging unit (Patent Document 2), or a method of supporting it by a PC steel wire stretched horizontally straddling between the end of the existing superstructure and the upper side of the overhanging unit (Patent Document 3) is known.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] The pier construction technology described above has the following problems that need to be addressed. <1> The working radius of a heavy equipment crane is affected by its installation location. Therefore, the heavy machinery crane will be installed near the tip of the existing superstructure, but from a safety standpoint, the crane's vehicle cannot extend beyond the tip of the existing superstructure. Thus, due to constraints on the installation location of heavy machinery cranes, the working radius of the heavy machinery cranes tends to be large. When the working radius of a heavy equipment crane increases, it becomes necessary to raise the standard size of the heavy equipment crane by one or several levels. <2> In the construction method of piers using cantilevered cantilever units, the cantilever units do not have the strength to support heavy machinery cranes, and if they were to be placed on top, there would be a risk of the heavy machinery cranes tipping over. <3> In the construction method of a pier using cantilevered cantilever units, the cantilevered units extending from the existing superstructure in the extension direction interfere with the main girders to be installed in the next span in the longitudinal girder direction, and therefore cannot be left in place. <4> In piers using cantilevered units, the erection of the units requires a lot of time and effort, resulting in high construction costs.

[0006] The objective of the present invention is to provide a cantilevered stage for a pier and a method for constructing a pier that can solve the conventional problems described above. [Means for solving the problem]

[0007] The present invention provides a detachable cantilever stage used when extending a superstructure composed of a plurality of support piles driven at intervals, a transverse girder erected between the heads of the support piles perpendicular to the bridge axis, a plurality of main girders erected between the transverse girders in the direction of the bridge axis, and a plurality of covering plates attached to the upper surfaces of adjacent main girders, the superstructure comprising the transverse girders, the plurality of main girders, and the plurality of covering plates, in the direction of the bridge axis, the auxiliary support frame that can be extended from the front end of the superstructure in the direction of the bridge axis, and the upper surface of the auxiliary support frame The auxiliary frame comprises a plurality of auxiliary covering plates, the auxiliary frame abuts against the front end of the main girder, a plurality of auxiliary girders extending in the direction of extension of the main girder, a tension top plate having a total length that can be stretched between the upper surface of the main girder and the upper surface of the auxiliary girders, and bracing members installed between adjacent auxiliary girders, and the tension top plate stretched between the main girder and the tension side of the auxiliary girders is connected with fixing bolts with the end faces of the auxiliary girders of the auxiliary frame in contact with the front end of the main girder, thereby making the auxiliary frame unable to tip over. In another embodiment of the present invention, the tensioned top plate of the auxiliary support frame is dimensionally longer than the total length of the auxiliary girder, and the tensioned top plate has a fixed portion that rests on the upper surface of the auxiliary girder and an overhanging portion that extends laterally from one side of the auxiliary girder. In another embodiment of the present invention, the fixing portion of the tensioned top plate and the auxiliary beam are integrally connected by bolting or welding. In another embodiment of the present invention, the total length of the auxiliary girder is shorter than the span length of the superstructure. In another embodiment of the present invention, a plurality of openings are provided on the bottom surface of the auxiliary covering plate, corresponding to the mounting positions of the fixing bolts. The present invention comprises the steps of erecting support piles at predetermined intervals, installing transverse girders perpendicular to the bridge axis between the heads of the support piles, installing a plurality of main girders in the direction of the bridge axis between the transverse girders, and installing a plurality of covering plates attached to the upper surfaces of adjacent main girders. alreadyA method for constructing a pier, comprising the step of extending the superstructure in span units between the heads of the plurality of support piles using a heavy machinery crane mounted on the superstructure, wherein one of the above-described cantilever stage is used, the end face of the auxiliary girder of the auxiliary frame is brought into contact with the front end of the main girder of the existing superstructure, the tension top plate stretched across the tension side of the main girder and the auxiliary girder is connected with fixing bolts to connect the auxiliary frame so as not to tip over, the cantilever stage is extended to the front end of the existing superstructure, and the superstructure of the next span is constructed using a heavy machinery crane mounted straddling the existing superstructure and the cantilever stage. In another embodiment of the present invention, a new superstructure is extended in front of the existing superstructure while attaching and detaching the cantilevered stage to the front end of the existing superstructure. In another embodiment of the present invention, with the end face of the auxiliary girder of the auxiliary support frame in contact with the front end of the main girder of the existing superstructure, the tension top plate is stretched across the tension side of the main girder and the auxiliary girder to connect them, and the auxiliary support frame extends from the front end of the existing superstructure in a cantilevered structure. [Effects of the Invention]

[0008] The present invention provides at least one of the following effects. <1> By extending a cantilevered stage from the front end of the existing superstructure of the pier, the installation position of the heavy machinery crane can be shifted toward the extended side of the existing superstructure during construction. Therefore, the working radius of the heavy equipment crane can be reduced. Reducing the working radius of the heavy equipment crane not only makes it possible to lower the standard size rank of the heavy equipment crane, but if the standard size of the heavy equipment crane is not reduced, it becomes possible to widen the spacing (span) of the support piles in the axial direction of the bridge during construction. <2> Because the auxiliary support frame that constitutes the cantilevered stage has a cantilever structure, the cantilevered stage can be installed with a simple operation: the end face of the auxiliary girder of the auxiliary support frame is brought into contact with the front end of the main girder of the existing superstructure, and the tension top plate, which is stretched across the tension side of the main girder and the auxiliary girder, is connected with fixing bolts. <3>When removing the extended stage, it can be separated by simply removing the fixing bolts and detaching the main girder from the tension top plate. <4>Since it is a cantilever structure that utilizes the tension top plate as a tension member, the horizontality of the extended stage can be maintained without providing support members such as "square poles" at the lower part of the auxiliary gantry that constitutes the extended stage. <5>Because the extended stage has a simple structure, it can be manufactured economically and is suitable for the groundwork structure.

Brief Description of the Drawings

[0009] [Figure 1] Side view of the trestle according to the present invention provided with an extended stage [Figure 2] Perspective view of the trestle according to the present invention provided with an extended stage [Figure 3] Perspective view of the auxiliary gantry that constitutes the extended stage [Figure 4] Side view of the enlarged extended stage assembled to the trestle [Figure 5] Bottom view of the auxiliary covering board with a part omitted [Figure 6] Planar model view of the process of extending the auxiliary gantry to the trestle [Figure 7] Side model view of the process of extending the auxiliary gantry to the trestle [Figure 8] Planar model view of the process of laying the auxiliary covering board on the auxiliary gantry [Figure 9] Side model view of the process of laying the auxiliary covering board on the auxiliary gantry [Figure 10] Planar model view of the trestle with the extended stage completed [[ID=^{}41]]

Modes for Carrying Out the Invention

[0010] [[ID=^{}46]] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0011] <1>Overhanging Structure of the Trestle The invention will be explained with reference to Figures 1 and 2. In this invention, a temporary cantilever stage 20 is horizontally extended from the front end of the existing superstructure 10b that constitutes the pier 10, and the cantilever stage 20 is utilized as an extension member of the existing superstructure 10.

[0012] <2> Pier configuration To describe the pier 10 shown in this example, the pier 10 comprises a plurality of support piles 11 erected at predetermined intervals, a transverse girder 12 stretched between the heads of adjacent support piles 11 perpendicular to the bridge axis, a plurality of main girders 13 stretched between adjacent transverse girders 12 perpendicular to the bridge axis, and a plurality of covering plates 14 laid on the main girders 13. Pier 10 may be temporary or permanent. The support pile 11 is made of, for example, an H-shaped steel or a steel pipe. The transverse beams 12 and main beams 13 are made of, for example, H-shaped steel.

[0013] In this example, we will describe a configuration in which the substructure 10a is composed of multiple support piles 11, and the superstructure 10b is composed of transverse girders 12, multiple main girders 13, and multiple decking plates 14.

[0014] <3> Projection stage The cantilevered stage 20 is a temporary superstructure for provisionally extending the existing superstructure 10b. The cantilevered stage 20 consists of a cantilevered auxiliary frame 30 that extends from the front end of the superstructure 10b in a way that prevents it from tipping over, and an auxiliary covering plate 25 laid on the auxiliary frame 30.

[0015] <3.1> Auxiliary mounting frame Referring to Figures 2 and 3, the auxiliary support frame 30 comprises a plurality of auxiliary girders 31 extending in the direction of extension of the main girder 13, a tension top plate 32 placed on the upper surface of each auxiliary girder 31 and protruding from one side of the auxiliary girder 31, and a brace member 33 installed between adjacent auxiliary girders 31 as a spacing member. The auxiliary support frame 30 may be manufactured as a single unit in advance at a factory or elsewhere and then transported to the site, or it may be assembled on-site.

[0016] <3.1.1> Auxiliary girder The auxiliary girder 31 is a girder member that functions as an extension member of the main girder 13, and is arranged at the same pitch as the main girder 13 and is made of steel material such as H-shaped steel with the same cross-sectional dimensions as the main girder 13. In this example, an end plate 34 is provided at the end of the auxiliary girder 31, but the end plate 34 is not essential and may be omitted. Bolt holes 31a are provided in the flange of the auxiliary girder 31.

[0017] The total length of the auxiliary girder 31 is shorter than the span length of the superstructure 10b. Specifically, the auxiliary girder 31 has a total length of 1 / 3 to 1 / 5 of the span length of the superstructure 10b. If the total length of the auxiliary girder 31 exceeds one-third of the length of the superstructure 10b, the overturning moment acting on the auxiliary girder 31 increases, making overturning more likely. In practical terms, the total length of the auxiliary girder 31 is approximately 2 meters.

[0018] The auxiliary girders 31 are arranged in parallel at predetermined intervals. The number of parallel auxiliary girders 31 can be appropriately selected according to the number of main girders 13 in the existing superstructure.

[0019] <3.1.2>Tensioned top plate The tension plate 32 is a tension member that connects the tension side of the connection between the main girder 13 and the auxiliary girder 31, and functions to prevent the auxiliary frame 30 from tipping over. The total length of the tensioned top plate 32 is longer than the total length of the auxiliary beam 31. The tensioned top plate 32 has a fixing portion 32a that is placed on and fixed to the upper surface of the auxiliary beam 31, and an overhanging portion 32b that extends laterally from one side of the auxiliary beam 31. The total length of the protruding section 32b can be selected as appropriate, but in practical terms, approximately 1 meter is sufficient.

[0020] The fixing portion 32a of the tensioned top plate 32 is integrally fixed to the upper surface of the main girder 13 by bolt connection or welding.

[0021] The overhang 32b is a part for fixing to the upper surface of the existing main girder 13, and multiple bolt holes 32c are provided therein. The overhang portion 32b of the auxiliary support frame 30 and the upper flange of the existing main girder 13 can be attached and detached using multiple fixing bolts 22.

[0022] <3.1.3> Brace Material The brace members 33 are spacing members stretched between adjacent main girders 13, and are made of rigid materials such as steel.

[0023] <3.2> Auxiliary covering plate The auxiliary covering plate 25 is a known rectangular covering plate. As shown in Figure 5, the auxiliary covering plate 25 has multiple openings 26 that are aligned with the mounting positions of the fixing bolts 22 so that its bottom surface does not interfere with the fixing bolts 22 described above.

[0024] [Pier construction methods] Next, we will explain the construction method for the pier using the cantilevered stage 20.

[0025] 1. Existing superstructure of the pier Figure 6 shows the existing superstructure 10b of the pier 10, in which the front ends of multiple main girders 13 are placed on the upper surface of the transverse girder 12 at the end of the superstructure 10b, and multiple covering plates 14 are laid on adjacent main girders 13. The method for extending the pier 10 using the cantilevered stage 20 will be explained below.

[0026] 2. Addition of an overhanging stage An overhanging stage 20 will be added to the front end of the existing superstructure 10b in the following manner.

[0027] <1> Suspension of the auxiliary frame As shown in Figures 6 and 7, the pre-fabricated auxiliary frame 30 is lifted up, and the base end of the auxiliary frame 30 is suspended from the front end of the superstructure 10b. At this time, the overhang portion 32b of the tension top plate 32, which extends horizontally from the auxiliary frame 30, is placed on the upper flange of the existing main girder 13, while the end face of the auxiliary girder 31 of the auxiliary frame 30, which is positioned on the same line, is brought into contact with the end face of the existing main girder 13. Furthermore, the lower surface of each auxiliary girder 31 is placed on the upper surface of the transverse girder 12 at the end of the superstructure 10b.

[0028] <2> Fixing the auxiliary frame As described above, with the end face of the auxiliary girder 31 of the auxiliary frame 30, which is positioned on the same line, in contact with the end face of the existing main girder 13, the overlapping portion where the overhang portion 32b of the auxiliary frame 30 and the upper flange of the existing main girder 13 are superimposed is fixed with multiple fixing bolts 22. Each auxiliary girder 31 is also secured to the lower flange and the cross girder 12 with a separate fixing bolt 22.

[0029] When the width of the superstructure 10b in the direction perpendicular to the bridge axis is wide, multiple sets of auxiliary support frames 30 are suspended as shown in Figure 6, and the adjacent auxiliary support frames 30 are connected with additional bracing members 35.

[0030] <3> Installation of auxiliary covering plates Next, as shown in Figures 8 and 9, the auxiliary covering plate 25 is laid on the auxiliary support frame 30. In this way, the cantilevered stage 20 is extended from the front end of the existing superstructure 10b. By connecting the cantilever stage 20 to the front end of the superstructure 10b, the total length of the superstructure 10b is effectively extended in the direction of the bridge axis. In this example, a safety fence 37 is installed at the front end of the overhanging stage 20, but the installation of the safety fence 37 may be omitted.

[0031] <4> Support for the overhanging stage Figure 4 shows the completed state with the cantilevered stage 20 extended from the front end of the superstructure 10b. The auxiliary support frame 30 has a cantilever structure in which the base end of its auxiliary girder 31 abuts against the front end of the existing main girder 13, and a tension top plate 32 is stretched across the tension side between the main girder 13 and the auxiliary girder 31. In Figure 4, a clockwise overturning moment acts on the cantilevered stage 20, with the base of the auxiliary girder 31 and the front end of the existing main girder 13 as the pivot points. Since the tension plate 32, which is stretched across the tension side between the main girder 13 and the auxiliary girder 31, functions as a tension member, the overturning of the cantilever stage 20 can be reliably restrained. The weight of the cantilevered stage 20 is supported by the main beam 13 and the cross beam 12 working together through the tensioned top plate 32.

[0032] Although the cantilevered stage 20 is cantilevered, the tensioning top plate 32 positioned on the tensioning side of the main girder 13 and auxiliary girder 31 functions as a tensioning member, thus restraining the downward tipping of the auxiliary frame 30 that constitutes the cantilevered stage 20, resulting in a structure that can stand independently. Therefore, it is possible to maintain the horizontality of the cantilever stage 20 without providing support members such as "braces" at the bottom of the auxiliary frame 30 that constitutes the cantilever stage 20.

[0033] 3. Access to the extended stage for heavy machinery cranes. Following the procedure outlined below, the heavy equipment crane 40 mounted on the pier 10 is positioned beyond the front end of the superstructure 10b.

[0034] <1> Location of heavy equipment crane entry point The traveling section of the heavy equipment crane 40 is moved onto the cantilevered stage 20, passing over the front end of the superstructure 10b, and then installed.

[0035] When a portion of the travel section of the heavy equipment crane 40 enters the cantilevered stage 20, the weight of the heavy equipment crane 40 is added to the cantilevered stage 20. As previously described, the cantilever stage 20 is prevented from tipping over by the tension top plate 32 stretched across the tension side of the main girder 13 and auxiliary girder 31, while supporting the load acting on the cantilever stage 20. Therefore, even if the traveling section of the heavy equipment crane 40 enters the cantilever stage 20, the overturning of the cantilever stage 20 can be effectively prevented. The downward load acting on the cantilevered stage 20, including the weight of the heavy equipment crane 40, is distributed and transmitted to the main girder 13, and ultimately supported by the support piles 11 through the transverse girder 12 on which the auxiliary girder 31 is mounted.

[0036] <2> Crane operations using heavy machinery cranes With the traveling section of the heavy equipment crane 40 mounted across the superstructure 10b of the pier 10 and the cantilevered stage 20, the prescribed work (such as erecting the support piles 11 for the next span and installing the transverse girders 12) is performed.

[0037] By extending the overhanging stage 20 of the heavy equipment crane 40 to the front end of the existing superstructure 10b, the heavy equipment crane 40 can be moved forward of the superstructure 10b by about 2m, thereby reducing the working radius of the heavy equipment crane 40. Therefore, crane operations using the heavy equipment crane 40 become easier.

[0038] <3> Center of gravity of heavy machinery crane When a lifting load is applied to the heavy equipment crane 40, the center of gravity G of the heavy equipment crane 40 moves forward. Since the overhanging stage 20 extending from the superstructure 10b has a projection length of about 2m, even if the center of gravity G of the heavy equipment crane 40 is displaced forward during crane operation, the center of gravity G remains within the range of the superstructure 10b. Therefore, even if the center of gravity G of the heavy equipment crane 40 is displaced forward, crane operations can be performed safely while preventing the heavy equipment crane 40 from tipping over.

[0039] 4. Removal of the protruding stage Once the heavy equipment crane 40 has completed its prescribed crane operations, the cantilevered stage 20 is dismantled by following the reverse process described above (not shown in the diagram).

[0040] <1> Retreating heavy equipment crane The heavy equipment crane 40, which had entered the cantilevered stage 20, is moved backward and then moved onto the superstructure 10b.

[0041] <2> Dismantling and removal of the protruding stage The auxiliary covering plate 25 on the auxiliary frame 30 is removed using the heavy equipment crane 40. Next, the fixing bolts 22 are loosened to separate the tensioned top plate 32 that is stretched between the main girder 13 and the auxiliary girder 31 of the auxiliary support frame 30, and the space between the auxiliary support frame 30 and the cross girder 12 is also separated, and the auxiliary support frame 30 is removed.

[0042] The dismantled and removed auxiliary support frames 30 and auxiliary covering plates 25 will be reused in the next span.

[0043] 5. Extension of the superstructure for the next span Using a heavy equipment crane 40, the main girder 13 is placed between adjacent transverse girders 12, and multiple covering plates 14 are laid on the adjacent main girder 13 to extend the superstructure 10b.

[0044] 6. Repeat The superstructure 10b is extended to a predetermined length by repeatedly assembling and disassembling the cantilevered stage 20. [Explanation of Symbols]

[0045] 10...Pier 10a... Substructure of the pier 10b... Superstructure of the pier 11...Support pile 12...Horizontal girder 13...Main girder 20..Extended Stage 22. Fixing bolts 25. Auxiliary covering plate 26... opening 30. Auxiliary stand 31.. Auxiliary girder 32..Tensioned top plate 32a... Fixing part of the tensioned top plate 32b...Protruding section of the tensioned top plate 32c... Bolt holes 33...Brace material 34...End plate 35. Additional bracing material 40.. Heavy machinery crane

Claims

1. A detachable cantilever stage is used to extend a superstructure in the direction of the bridge axis, comprising a plurality of support piles driven at intervals, a transverse girder erected between the tops of the support piles perpendicular to the bridge axis, a plurality of main girders erected between the transverse girders in the direction of the bridge axis, and a plurality of covering plates attached to the upper surfaces of adjacent main girders. An auxiliary support structure that can extend from the front end of the superstructure in the direction of the bridge axis, The system comprises a plurality of auxiliary covering plates laid on the upper surface of the aforementioned auxiliary support frame, The auxiliary support frame abuts against the front end of the main girder and comprises a plurality of auxiliary girders extending in the direction of extension of the main girder, A tensioned top plate having a total length that can be stretched between the upper surface of the main beam and the upper surface of the auxiliary beam, It comprises a brace member installed between adjacent auxiliary girders, The auxiliary frame is configured to be unable to tip over by connecting the tension top plate, which is stretched across the tension side of the main girder and the auxiliary girder, with fixing bolts, while the end face of the auxiliary girder of the auxiliary frame is in contact with the front end of the main girder. A projecting stage for use on piers.

2. The cantilever stage for a pier according to claim 1, characterized in that the tensioned top plate of the auxiliary support frame is dimensionally longer than the total length of the auxiliary girder, and the tensioned top plate has a fixed portion that rests on the upper surface of the auxiliary girder and an overhanging portion that extends laterally from one side of the auxiliary girder.

3. The cantilever stage for a pier according to claim 2, characterized in that the fixing portion of the tensioned top plate and the auxiliary girder are integrally connected by bolt connection or welding.

4. The cantilever stage for a pier according to claim 1, characterized in that the total length of the auxiliary girder is shorter than the span length of the superstructure.

5. The cantilevered stage for a pier according to claim 1, characterized in that a plurality of openings are provided on the bottom surface of the auxiliary covering plate in accordance with the mounting positions of the fixing bolts.

6. A method for constructing a pier, comprising the steps of erecting support piles at predetermined intervals, and extending the superstructure in span units between the heads of the multiple support piles using a heavy equipment crane mounted on an existing superstructure which consists of transverse girders erected perpendicular to the bridge axis between the heads of the support piles, multiple main girders erected in the direction of the bridge axis between the transverse girders, and multiple covering plates attached to the upper surfaces of adjacent main girders, Using the extension stage described in any one of claims 1 to 5 above, With the end face of the auxiliary girder of the auxiliary frame in contact with the front end of the main girder of the existing superstructure, the tension top plate, which is stretched across the tension side of the main girder and the auxiliary girder, is connected with fixing bolts to securely connect the auxiliary frame so that it cannot tip over, thereby extending an overhanging stage to the front end of the existing superstructure. The construction of the next span's superstructure is characterized by using a heavy equipment crane installed across the existing superstructure and the cantilevered stage. Construction methods for piers.

7. A method for constructing a pier according to claim 6, characterized in that a new superstructure is extended in front of the existing superstructure while attaching and detaching the cantilevered stage to the front end of the existing superstructure.

8. A method for constructing a pier according to claim 6, characterized in that the end face of the auxiliary girder of the auxiliary support is brought into contact with the front end of the main girder of the existing superstructure, the tension top plate is stretched across the tension side of the main girder and the auxiliary girder to connect them, and the auxiliary support extends from the front end of the existing superstructure in a cantilevered structure.

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