JP6712201B2 - How to build a pier - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pier construction method in which an overhanging portion such as a beam portion overhanging from the head of a pier is integrally constructed.

When building a pier adjacent to a roadway, if the beam part that is integrated with the head of the pier overhangs on the roadway side, it will be necessary to regulate the passage of vehicles, which may cause traffic congestion. ..

On the other hand, in Patent Document 1, a pier lower part, a top part and a beam part which are integrally constructed by reinforced concrete in a yard parallel to a roadway are rotated toward a roadway side by a turntable installed on the foundation of the pier. A method of constructing a bridge pier is disclosed. According to this construction method, since the construction of the lower part of the pier, the top and the beam is performed within the yard, there is no need to regulate traffic, and traffic congestion can be suppressed.

JP-A-8-296210

However, according to the method disclosed in Patent Document 1, since the entire pier from the lower part of the pier to the beam portion is rotated, a rotating device including a rotary base becomes large. In addition, when the pier becomes large and the distance between the upper part of the foundation, which is the center of rotation, and the beam portion becomes long, a large rotational moment may act, resulting in an unstable state during rotation.

Therefore, an object of the present invention is to provide a pier construction method that can be safely constructed using a simple rotating device regardless of the scale of the pier.

In order to achieve the above-mentioned object, the pier construction method of the present invention is a pier construction method in which an overhanging portion protruding from the head of the pier is integrally constructed, and a step of constructing the pier legs , A step of installing a lower supporting frame surrounding the leg portion and having an annular upper surface formed at a position higher than the upper surface of the leg portion, and freely movable along a lower layer portion installed on the annular upper surface A rotating device with a different upper layer, installing a plurality of vertically expandable and contractible jacks at intervals in the upper layer, and extending the upper support frame for constructing the head of the pier. Supporting the plurality of jacks that have been formed, installing a form on the upper support frame and installing a form for constructing the overhang, and constructing the head and overhang. A step of removing the mold of the overhanging part, and a step of rotating the head and the overhanging part supported by the upper support frame by moving the upper layer part along the lower layer part of the rotating device. And a step of constructing a connection part for connecting the head part and the leg part, a step of contracting the jack part to remove the upper support frame, and a step of removing the rotating device and the lower support frame. And a process.

Here, it can be configured to include a step of connecting the leg portion of the pier and the lower support frame. Further, the rotating device includes an annular lower layer portion, an annular upper layer portion that covers the lower layer portion, and a plurality of rotating bodies or lubricant portions that are interposed between the lower layer portion and the upper layer portion. It is preferably constructed.

Further, a hydraulic jack and a mechanical jack may be arranged as the jack section. In addition, it is preferable that rotation of the rotating device is restricted by a stopper except for a step of moving the upper layer portion along the lower layer portion. Further, the lower support frame can be configured to be installed on a base table provided on an upper surface of a base portion to which the leg portions are connected.

The bridge pier construction method of the present invention configured as described above does not rotate the legs of the pier, but uses the rotating device installed in the lower support frame whose annular upper surface is located above the legs to extend the head and the overhang. Rotate only part.

Therefore, even if the pier becomes large, the distance between the rotation center and the overhanging portion can be suppressed, so that a simple rotating device can be used. In addition, since the rotation moment is suppressed, it is possible to rotate stably, and it is possible to carry out the construction safely.

Further, by connecting the lower support frame to the legs of the pier, it is possible to secure a reaction force of the force that acts on the lower support frame during rotation, and more stable rotational movement can be performed.

Furthermore, if the rotating device is configured by interposing a plurality of rotating bodies or lubricant parts between the annular lower layer part and the upper layer part, it is possible to reliably rotate and move even if the weight is large with a simple structure. Can be

In addition, if a hydraulic jack and a mechanical jack are arranged as the jack section, after adjusting the height with the hydraulic jack, the mechanical jack will support it stably for a long time, which is efficient and economical. It is possible to perform specific construction.

Further, by using the rotating device having the stopper that restrains the rotational movement, it is possible to reliably prevent the unintentional occurrence of the rotational movement of the machine, and it is possible to improve the safety of the construction.

Further, if the lower support frame is installed on the base table provided on the upper surface of the base to which the legs are connected, the load transmitted from the lower support frame to the base can be dispersed.

It is a perspective view explaining the construction method of the bridge pier of the embodiment of the invention. It is sectional drawing explaining the process of constructing the foundation part and the leg part of a pier. It is a perspective view explaining the process of joining a connection part to the leg part of a pier. It is a perspective view explaining the arrangement relation of a leg part of a pier, a connection part, and a lower support frame. It is a perspective view explaining the composition of a rotation device. It is a perspective view explaining the process of installing a hydraulic jack and a giraffe jack on the rotation device attached to the lower supporting frame. It is a perspective view explaining the process of making a hydraulic jack and a giraffe jack support an upper support frame. It is sectional drawing explaining the process of constructing the head part and beam part of a pier. It is a perspective view explaining the process of rotating and moving with a rotating device. It is a perspective view explaining composition of a stopper of a rotation device. It is a perspective view explaining the process of constructing the connection part of a pier. It is a perspective view explaining the process of removing the upper support frame. It is a perspective view explaining the whole structure of the constructed bridge pier. It is a top view explaining the composition of the rotation device of an example. It is sectional drawing seen in the AA arrow direction of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the pier construction method of the present embodiment, the pier 1 as shown in FIG. 13 is constructed. The pier 1 is constructed so as to be integrated with reinforced concrete, prestressed concrete, or the like.

The pier 1 is provided on a foundation 15 such as a footing. Here, the lower portion of the bridge pier 1 joined to the foundation portion 15 is the leg portion 11, the intermediate portion above it is the connecting portion 13, and the upper portion of the pier 1 is the head portion 12.

The overhanging portions projecting from the head portion 12 on both sides are beam portions 14 and 14, and the head portion 12 is provided with arm portions 121 and 121 continuous with the beam portions 14 and 14. The beam portions 14, 14 are projected above the roadways R, R through which the vehicle passes. On the other hand, between the roads R on both sides, there is a median strip R2 where no vehicle passes, and it can be used as a working yard without traffic regulation.

Next, a method of constructing a bridge pier according to the present embodiment will be described in the order of steps.

First, as shown in FIG. 2, the foundation part 15 is constructed by using the inside of the median strip R2 sandwiched between the roads R, R as a working yard. The inside of the median strip R2 is separated from the road R by the fence R1, so that the vehicle does not enter and the work such as excavation can be performed without restriction.

Therefore, an excavation part 160 protected by the mountain retaining wall 16 is provided at a construction site in the median strip R2, and a basal part 15 of, for example, a rectangular parallelepiped shape is constructed on the bottom plate 161 by reinforced concrete or the like. It should be noted that a pile is constructed below the foundation portion 15 if necessary, but a detailed description thereof will be omitted here.

Then, a columnar or elliptical columnar leg 11 is constructed in the center of the base portion 15. The leg portion 11 is constructed of reinforced concrete or the like so as to be joined and integrated with the base portion 15.

As shown in FIG. 3, an annular plate-shaped base base 2 is installed around the legs 11 on the upper surface of the base portion 15. The base 2 is configured by combining a plurality of arc plates, for example.

That is, a plurality of arc-shaped plates are brought close to each other from the lateral side of the leg portion 11 so that the outer periphery of the lower end of the leg portion 11 is surrounded by the base 2. Then, the side edge of the connecting portion 33 is joined to the side surface of the leg portion 11.

The connecting portion 33 includes leg side members 331 that extend vertically along the side surfaces of the leg portions 11, support side members 332 that are installed on the base 2 that is substantially parallel to the leg side members 331, and leg side members. It is mainly configured by a connecting member 333 that connects between the support member 332 and the supporting side member 332. The connecting portion 33 is manufactured by combining steel materials such as H-shaped steel.

The leg side member 331 is formed to have substantially the same length as the height of the leg portion 11 and is fixed to the leg portion 11 by an anchor bolt or the like. On the other hand, the supporting side member 332 has the lower end surface in contact with the upper surface of the base 2.

Subsequently, as shown in FIG. 4, the lower support frame 3 is installed so as to surround the connecting portions 33, 33 provided on both sides of the leg 11 from the outside. The lower support frame 3 is mainly configured by an upper ring portion 31 on which an annular upper surface 311 is formed, and a plurality of column portions 32,... Hanging from the upper ring portion 31.

The lower support frame 3 is manufactured by combining steel materials such as H-shaped steel so as to surround the leg portions 11. The inner diameter of the upper ring portion 31 is about the total length of the leg portion 11 and the connecting portions 33, 33 provided on both sides thereof.

The pillar portions 32,... Are provided at equal intervals, for example, along the circumferential direction of the upper ring portion 31. The side surfaces of the supporting side members 332 and 332 of the connecting portions 33 and 33 are joined to the inner side surfaces of the pair of supporting column portions 32 and 32 facing each other.

The lower ends of the support columns 32,... Are installed on the upper surface of the base 2 and fixed to the base 2 with anchor bolts or the like, but are connected to the legs 11 via the connecting portions 33, 33. The support frame 3 has a higher resistance to horizontal force. That is, the lower support frame 3 does not easily fall down even if an earthquake force or an external force due to the operation of the rotating device 4 described later acts.

The rotating device 4 as shown in FIG. 5 is attached to the upper ring portion 31 of the lower support frame 3. The rotating device 4 includes a ring-shaped lower layer portion 41, a ring-shaped upper layer portion 43 that covers the lower layer portion 41 from above, and a sphere as a plurality of rotating bodies interposed between the lower layer portion 41 and the upper layer portion 43. 42 and so on.

The lower layer portion 41 is a plate-shaped member having substantially the same planar shape as the annular upper surface 311 of the upper ring portion 31, and two groove portions 411 and 411 are provided on the upper surface in parallel along the circumferential direction.

The upper layer portion 43 facing the lower layer portion 41 is formed in an annular plate shape that covers the lower layer portion 41, and has groove portions 431 and 431 facing the groove portions 411 and 411. Further, on the inner peripheral side of the upper layer portion 43, a hanging wall portion 432 that hangs down so as to cover the inner peripheral surface of the lower layer portion 41 is provided to prevent falling.

Then, spheres 42 such as steel balls are continuously arranged between the groove portion 411 of the lower layer portion 41 and the groove portion 431 of the upper layer portion 43. In the rotating device 4 configured as described above, the upper layer portion 43 can be freely moved along the lower layer portion 41 with a small resistance. The relative circumferential movement of the upper layer portion 43 with respect to the lower layer portion 41 is referred to as “rotational movement”.

This rotational movement is constrained by a stopper 46 as shown in FIG. 10 when the rotational movement is not necessary so that it does not occur unintentionally. The stopper 46 is a jig for sandwiching the lower layer portion 41 and the upper layer portion 43, and restrains the rotational movement by a vertical tightening force. The stopper 46 is not limited to this, and may be configured to restrain the rotational movement by a shear resistance such as a pin or a bolt penetrating the lower layer portion 41 and the upper layer portion 43.

FIG. 6 shows a state in which the rotating device 4 is attached to the upper ring portion 31 of the lower support frame 3. The upper layer portion 43 of the rotating device 4 is provided with arcuate arc bases 44, 44 at positions facing each other. The circular arc bases 44, 44 are fixed to the upper layer portion 43 and rotate together.

The hydraulic jacks 51 and the giraffe jacks 52 are alternately installed on the upper surface of the arc base 44 at intervals. The hydraulic jack 51 is a hydraulic jack that can expand and contract depending on the supplied hydraulic pressure. On the other hand, the giraffe jack 52 is a mechanical jack that moves up and down by the rotation of a screw and can maintain an adjusted length without power.

Then, as shown in FIG. 7, the upper support frame 6 is supported by the plurality of jacks (51, 52) installed on the arc base 44. The upper support frame 6 is a member serving as support work for constructing the head 12 of the pier 1.

The upper support frame 6 can be made of steel plate, steel material, or the like. A rectangular frame-shaped bottom surface 61 is formed on the upper support frame 6, and a central opening portion 62 and side opening portions 63, 63 at both ends are formed on the side surface side.

The bottom surface 61 of the upper support frame 6 is formed in a region surrounding the head 12 to be constructed, and is placed on the upper end surfaces of the hydraulic jacks 51,.... The upper support frame 6 is initially supported only by the hydraulic jacks 51,....

Then, the hydraulic jacks 51,... Are extended to adjust the height position of the upper support frame 6, and then the giraffe jack 52 disposed between the hydraulic jacks 51, 51 is extended to make the upper end surface bottom surface 61. Contact. By replacing the giraffe jacks 52,... In this way, it is not necessary to continue supplying the hydraulic pressure of the hydraulic jack 51.

As shown in FIG. 8, the upper support frame 6 is provided with a mold 71 for molding the side surface of the head 12 using the central opening 62 and the like. Further, if necessary, a mold is installed below the bottom surface 61 of the upper support frame 6.

On the other hand, in the median strip R2, which is the working yard, the support parts 74, 74 are assembled from the ground on both sides of the open-cut part 160. The support members 74, 74 serve as support members for the formwork 73, 73 for constructing the beam portions 14, 14.

Further, the mold 71 and the molds 73, 73 are connected by the molds 72, 72 for constructing the arm 121. After the molds 71-73 are installed in this way, the reinforcing bars to be the head 12, the arms 121, 121, and the beams 14, 14 are assembled, and the inside of the molds 71-73 is filled with concrete.

After the concrete hardens and reaches a predetermined strength, the molds 72 and 73 are released from the mold, and the supporting member 74 is dismantled. FIG. 1 shows a state in which the molds 72, 73 and the supporting structure 74 are removed. At this time, the head portion 12 and the beam portions 14, 14 of the pier 1 are in a state of being supported by the upper support frame 6. The upper support frame 6 supported by the giraffe jacks 52,... Is in a state in which it can be rotationally moved along with the upper layer portion 43 of the rotating device 4.

Therefore, a step of rotating the rotating device 4 to orient the beam portions 14, 14 on the roads R, R is carried out. As shown in FIG. 9, the upper layer portion 43 of the rotating device 4 is connected to the lower support frame 3 via the horizontal jack 45.

That is, the rear end of the cylinder portion 451 of the horizontal jack 45 is connected to the mounting portion 34 of the lower support frame 3. On the other hand, the tip of the piston portion 452 of the horizontal jack 45 is connected to the upper layer portion 43 of the rotating device 4. Therefore, when the horizontal jack 45 is extended, the reaction force is secured by the lower support frame 3, so that the upper layer portion 43 is pushed out by the piston portion 452.

At this time, as shown in FIG. 10, since the constraint by the stopper 46 is released, the upper layer portion 43 can be moved relatively to the lower layer portion 41. In the present embodiment, 90° rotational movement is performed.

Here, by overhanging the stopper 46 on the movement path of the arc base 44, it is possible to prevent excessive rotation. In short, by making the end surface of the circular arc base 44 contact the stopper 46 after the rotation movement of 90 degrees, the rotation movement of a desired angle can be performed. After the rotational movement, the stopper 46 again holds the lower layer portion 41 and the upper layer portion 43 to restrain the rotational movement.

Subsequently, as shown in FIG. 11, a bar arrangement for constructing the connecting portion 13 is performed between the lower end of the head 12 and the upper end of the leg 11. Then, an intermediate form 75 is provided to connect the outer peripheral surface of the head 12 and the outer peripheral surface of the leg 11 to each other.

When the inside of the intermediate form 75 is filled with concrete, the connection portion 13 that integrates the head portion 12 and the leg portion 11 is constructed. After the concrete hardens and reaches a predetermined strength, the intermediate form 75 is released from the mold, and hydraulic pressure is supplied to the hydraulic jacks 51,... to replace the giraffe jacks 52,.

As shown in FIG. 12, the upper support frame 6 supported only by the hydraulic jacks 51,... Can be lowered by contracting the hydraulic jacks 51,. When the upper support frame 6 is lowered, a gap is created between the form 71 and the head 12 and the upper support frame 6 is separated.

As a result, the load acting on the mold 71 and the upper support frame 6 is released, and it becomes easier to disassemble. After removing the form 71 and the upper support frame 6, the hydraulic jacks 51,... And the rotating device 4 are removed.

Then, when the lower support frame 3, the connecting portion 33, and the base 2 are removed in this order, as shown in FIG. 13, the bridge pier 1 in which the beam portions 14 and 14 project above the roadways R and R is completed. Become.

On the other hand, the removed upper support frame 6, the jack parts (51, 52), the rotating device 4 lower support frame 3, the connecting part 33 and the base 2 are transported to the next construction site to construct another pier 1. Used for.

Next, the operation of the pier construction method of the present embodiment will be described.

The bridge pier construction method of the present embodiment configured as described above is installed in the lower support frame 3 in which the annular upper surface 311 is located above the upper surface of the leg 11 without rotating the leg 11 of the pier 1. Only the head portion 12 and the beam portions 14, 14 are rotated by the rotating device 4.

Therefore, even if the pier 1 becomes large, it is possible to prevent the distance from the rotating device 4 serving as the center of rotation from the beam portion 14 to be long, so that the simple rotating device 4 can be used. In addition, since the rotation moment is suppressed, it is possible to rotate stably, and it is possible to carry out the construction safely.

Further, the upper support frame 6, the jack portions (51, 52), the rotating device 4, the lower support frame 3, the connecting portion 33, and the base 2 required for the rotational movement are all recoverable and can be reused. ..

Further, by connecting the lower support frame 3 to the leg portion 11 of the pier 1, a reaction force of the force acting on the lower support frame 3 at the time of rotation can be secured, and more stable rotational movement can be performed. .. For example, when the horizontal jack 45 whose end portion is connected to the lower support frame 3 is extended and the rotating device 4 is rotationally moved, the reaction force of the horizontal jack 45 near the upper edge of the lower support frame 3 becomes a horizontal force. Although it works, if it is fixed to the leg portion 11 via the connecting portions 33, 33, the lower support frame 3 can be rotationally moved without causing a shift or the like.

Further, even if a horizontal force acts on a high position such as the upper portion of the pier 1 due to an earthquake or wind, the cylindrical lower support frame 3 fixed to the leg portion 11 via the connecting portions 33, 33 is stable. It is expensive and can prevent falls.

On the other hand, in the case of the rotating device 4 configured by interposing a plurality of spherical bodies 42,... Between the annular lower layer portion 41 and the upper layer portion 43, the rotation mechanism is simple and the applied load is applied. Even if becomes large, it is possible to surely perform the rotational movement.

Further, if two types of the hydraulic jack 51 and the giraffe jack 52 are arranged as jack parts, after the height adjustment is performed by the hydraulic jack 51, the hydraulic pressure supply is stopped and the giraffe jack 52 stabilizes for a long time. Therefore, efficient and economical construction can be performed.

Further, by using the rotating device 4 having the stopper 46 that restrains the rotational movement, it is possible to reliably prevent the unintentional occurrence of the rotational movement of the time machine, and it is possible to improve the safety of the construction. Further, the stopper 46 can prevent excessive rotation.

Further, if the lower support frame 3 is installed on the base table 2 provided on the upper surface of the base portion 15 to which the leg portions 11 are connected, the loads of the column portions 32,... Since the load is received by the base 2 and is transmitted to the base portion 15 via the planar base base 2, it is possible to disperse the acting load and prevent the base portion 15 from being damaged.

Hereinafter, a rotating device 8 of a different form from the rotating device 4 described in the above embodiment will be described with reference to FIGS. 14 and 15. Note that description of the same or equivalent parts as the contents described in the above embodiment will be made using the same terms or the same reference numerals.

The rotating device 8 described in the present embodiment is interposed between an annular lower layer portion 81, an annular upper layer portion 83 arranged above the lower layer portion 81, and the lower layer portion 81 and the upper layer portion 83. It is mainly configured by the plurality of lubricant members 82,....

As shown in FIG. 15, the lower layer portion 81 is a planar groove member having a width slightly smaller than the annular upper surface 311 of the upper ring portion 31 of the lower support frame 3. That is, the lower layer portion 81 is integrally formed with an annular plate-shaped bottom portion 811 and side wall portions 812 and 812 that are erected along the inner edge and the outer edge of the bottom portion 811.

Further, retaining walls 813,... Are provided at intervals in the circumferential direction of the side wall portions 812 and 812, and are supported from the side. Further, the upper surface of the bottom portion 811 is coated with fluorine or the like to reduce frictional resistance.

On the other hand, the upper layer portion 83 is formed in an annular shape having a size that can be accommodated in the concave groove of the lower layer portion 81. For example, it is formed in a cross-shaped cross section in which H-shaped steels are arranged in parallel. Then, the lubricant material portion 82 is attached to the lower surface side of the bottom plate portion 831 of the upper layer portion 83.

The lubricant portion 82 is made of, for example, a cast nylon (6 nylon) material or the like in a sheet shape and has a low friction and excellent wear resistance, and a grease material such as molybdenum grease to be applied or impregnated on the nonwoven material. Formed by.

The lubricant portion 82 is attached to the bottom plate portion 831 of the upper layer portion 83 by bolts 832 and 832. In addition, as shown in FIG. 14, a plurality of lubricant portions 82 formed in a rectangular shape in plan view are attached at intervals in the circumferential direction of the upper layer portion 83.

Further, in order to prevent lateral blurring of the upper layer portion 83 that rotates and moves along the lower layer portion 81, as shown in FIG. 15, arms 841 having roller portions 84 are extended from both side surfaces of the upper layer portion 83. Roller parts 84, 84 such as roller followers attached to the ends of the arms 841, 841 are brought into contact with the inner peripheral surfaces of the side wall parts 812, 812 of the lower layer part 81.

Further, as shown in FIG. 14, a connecting fitting 851 of the horizontal jack 85 is attached to the outer surface of the upper layer portion 83. The connecting metal fitting 851 is a metal fitting that connects the tip of the horizontal jack 85 and the upper layer portion 83, and is detachable, and is replaced with the upper layer portion 83 each time the horizontal jack 85 makes one stroke.

The rotating device 8 of the embodiment configured as described above can be configured by interposing a plurality of lubricant members 82,... Between the annular lower layer portion 81 and the annular upper layer portion 83, and thus has a simple structure. Therefore, even if the weight becomes large, it can be surely rotated.

The other configurations and effects of the embodiment are substantially the same as those of the above-described embodiment, and thus the description thereof will be omitted.

The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific configuration is not limited to this embodiment, and a design change that does not depart from the gist of the present invention is Included in the invention.

For example, in the above-described embodiment, the beam portions 14 and 14 for widening the head portion 12 of the pier 1 in the direction orthogonal to the bridge axis are described as the projecting portions, but the present invention is not limited to this.

Further, in the above-described embodiment, the beam portion 14 integrally formed with the head 12 by reinforced concrete has been described as an example, but the present invention is not limited to this, and the steel portion manufactured using a steel plate or a steel frame is used. It may be an overhang part or an overhang part made of precast concrete.

Further, in the above-described embodiment, the rotating device 4 including the annular lower layer portion 41 and the upper layer portion 43 and the plurality of spherical bodies 42,... However, the rotating device may be configured by, for example, a rail serving as a lower layer portion and a slider serving as an upper layer portion.

Moreover, although the said embodiment demonstrated the structure which arrange|positions the giraffe jack 52 between the hydraulic jacks 51, 51, it is not limited to this. For example, after the upper support frame 6 is raised by the hydraulic jacks 51, 51, steel material or the like is used as a temporary support material (sandle) and is interposed between the rotating device 4 and the bottom surface 61 of the upper support frame 6, whereby the hydraulic jack 51,... Can be exchanged.

Furthermore, in the above-described embodiment and examples, the configuration in which the rotating devices 4 and 8 are rotationally moved by the horizontal jacks 45 and 85 has been described, but the present invention is not limited to this. For example, it can be rotated by a lever block (registered trademark), a chain block, a device using an electric motor, or the like.

1 Bridge pier 11 Leg part 12 Head part 13 Connection part 14 Beam part (overhang part)
2 base stand 3 lower support frame 311 annular upper surface 33 connecting portion 4 rotating device 41 lower layer portion 42 spherical body (rotating body)
43 Upper Layer 46 Stopper 51 Hydraulic Jack (Hydraulic Jack, Jack)
52 Kirin jack (mechanical jack, jack part)
6 Upper support frames 71, 72, 73 Form 8 Rotating device 81 Lower layer part 82 Lubricant part 83 Upper layer part

Claims (6)

A method of constructing a pier, in which an overhanging portion projecting from the head of the pier is constructed integrally,
The process of building the legs of the pier,
Installing a lower support frame that surrounds the leg portion and has an annular upper surface formed at a position higher than the upper surface of the leg portion;
Attaching a rotating device having an upper layer portion freely movable along the lower layer portion installed on the annular upper surface;
A step of installing a plurality of vertically expandable and contractible jack parts at intervals in the upper layer part;
Supporting the upper support frame for constructing the head of the pier on the extended plurality of jacks,
Installing a form on the upper support frame and installing a form for building the overhang,
A step of constructing the head portion and the overhanging portion and demolding the formwork of the overhanging portion;
Moving the upper layer portion along the lower layer portion of the rotating device to rotationally move the head portion and the overhanging portion supported by the upper support frame;
A step of constructing a connecting portion connecting the head portion and the leg portion,
A step of contracting the jack part to remove the upper support frame,
And a step of removing the rotation device and the lower support frame. The method for constructing a pier according to claim 1, further comprising a step of connecting a leg portion of the pier and the lower support frame. The rotating device is configured by an annular lower layer portion, an annular upper layer portion that covers the lower layer portion, and a plurality of rotating bodies or lubricant portions interposed between the lower layer portion and the upper layer portion. The method for constructing a pier according to claim 1 or 2, characterized in that: The method for constructing a pier according to any one of claims 1 to 3, wherein a hydraulic jack and a mechanical jack are arranged as the jack portion. 5. The pier of the pier according to any one of claims 1 to 4, wherein the rotating device has rotational movement restrained by a stopper except for a step of moving the upper layer portion along the lower layer portion. How to build. The said lower support frame is installed in the base stand provided in the upper surface of the foundation part to which the said leg part is connected, The construction method of the pier of any one of Claim 1 thru|or 5 characterized by the above-mentioned.