JP6364210B2 - Bridge pier reinforcement structure - Google Patents

Description

  The present invention relates to a reinforcement structure for a pier.

  When reinforcing the pier (under construction), the proof strength of the pier base that connects the column and the footing may be increased.

  For example, in the reinforcement structure of Patent Document 1, the existing base plate of the pier base is expanded by on-site welding, and an anchor bolt is added outside the existing anchor bolt provided around the column, thereby increasing the tensile resistance. ing.

Japanese Patent Laid-Open No. 10-8422

In order to increase the anchor bolt, it is necessary to drill the existing footing, but it is necessary to avoid interference between the drilled portion and the reinforcing bar of the existing footing.
Further, when the bolt diameter of the additional anchor bolt is large, there is a concern that the adhesion resistance with the concrete is reduced due to the group effect, the overlap of the shear resistance area with the existing anchor bolt or the uncertain load sharing.

  From such a viewpoint, it is an object of the present invention to provide a pier reinforcement structure that is excellent in workability and has a clear reinforcement effect.

In order to solve the above problems, a reinforcement structure for a pier of the present invention includes a widening member retrofitted to a base portion of an existing column, and is disposed so as to surround the base portion of the existing column, and a pier base plate of the existing column is already installed. The existing anchor bolts on the tension side and the concrete on the compression side are increased outside the existing anchor bolts fixed to the footing without increasing the resistance force or adding anchor bolts for fixing the widening member to the existing footing . be one that improves the yield strength bearing capacity, the wider member is connected to the reinforcing base plate is placed in a state in which the whole lower surface to the upper surface is in contact with the existing footing, and said reinforcing base plate and the side surface of the existing pillar It is characterized by comprising a rib plate.

According to the reinforcing structure of the pier, a reinforcing structure with a clear reinforcing effect can be constructed. In other words, by increasing the bearing resistance resistance area of the concrete with the reinforced base plate, the neutral shaft can be moved to the compression side. Can be improved.
Moreover, since it is not necessary to drill the existing foundation, it does not interfere with the existing reinforcing bars and is excellent in workability.

  If the reinforcing base plate is joined to the pier base plate of the existing pillar, a truss structure in which the rib plate is regarded as an oblique material and the reinforcing base plate is regarded as a chord material can be constructed.

  The rib plate is preferably fixed to the existing column via a joint member fixed to a side surface of the existing column.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the reinforcement structure of a bridge pier excellent in workability | operativity and a clear reinforcement effect.

It is a front view which shows the reinforcement structure of the bridge pier of this embodiment. It is XX sectional drawing of FIG. (A) is a perspective view which shows the preparatory process of the construction method of a reinforcement structure, (b) is the same expanded sectional view. (A) is a perspective view which shows the attachment condition of the joint member of a widening member formation process, (b) is a perspective view which shows the installation condition of the reinforcement baseplate. (A) is a front view which shows the installation condition of a reinforcement baseplate, (b) is the same expanded sectional view. (A) The perspective view which shows the formation condition of the widening member following FIG. 4 and FIG. 5, (b) is the same expanded sectional view. It is a perspective view which shows a root winding concrete placement process.

A bridge pier reinforcement structure (hereinafter simply referred to as “reinforcement structure”) 1 according to the present embodiment reinforces a pier 2 including an existing pillar 3 and an existing footing (existing foundation) 4.
As shown in FIG. 1, the reinforcing structure 1 includes a widening member 10 retrofitted to the base of the existing pillar 3, and a root concrete 11 around which the base of the existing pillar 3 and the widening member 10 are wound.

The existing pillar 3 is fixed to the existing footing 4.
The existing footing 4 of the present embodiment is a reinforced concrete structure. An anchor frame 5 is embedded in the existing footing 4. The shape of the existing footing 4 is not limited.

  The anchor frame 5 generally has a structure formed by combining a plurality of anchor bolts 51 and two upper and lower frame-shaped members 52, but the shape of the anchor frame 5 is not limited.

The anchor bolt 51 is embedded in the existing footing 4 with the head protruding from the upper surface of the existing footing 4.
As shown in FIG. 2, the plurality of anchor bolts 51 are disposed so as to surround the base (lower end) of the existing pillar 3. The number of anchor bolts 51, the arrangement pitch, the bolt diameter, etc. are not limited.

The frame-shaped member 52 is formed by combining steel materials or the like into a frame shape. The frame-like member 52 connects a plurality of anchor bolts 51, 51,... (See FIG. 1).
In this embodiment, as shown in FIG. 1, the frame-shaped member 52 is arranged in two upper and lower stages, but the number of stages of the frame-shaped member 52 is not limited.

As shown in FIG. 2, the existing pillar 3 of the present embodiment has a rectangular shape in plan view.
The existing pillar 3 is fixed to the existing footing 4 via an anchor frame 5 (anchor bolts 51, 51,...). In addition, the fixing method of the existing pillar 3 and the existing footing 4 is not limited to the method using the anchor frame 5.

A base member 30 is provided around the lower end of the existing pillar 3.
The base member 30 is formed at the lower end portion of the existing column 3 so as to protrude from the side surface of the existing column 3.

  As shown in FIG. 1, the base member 30 of the present embodiment includes an abutment base plate 31 fixed to the lower end of the existing pillar 3, and a second abutment base plate 32 disposed above the abutment base plate 31 with a space therebetween. The pier base plate 31 and the second pier base plate 32 are provided with ribs 33 interposed therebetween.

  A through hole is formed in the pier base plate 31 and the second pier base plate 32 corresponding to the position of the anchor bolt 51. The anchor bolts 51, 51,... Planted in the existing footing 4 are inserted through the through holes of the pier base plate 31 and the second pier base plate 32.

The existing column 3 is fixed to the existing footing 4 by fastening nuts 53 to the heads of the anchor bolts 51, 51,... Penetrating the pier base plate 31 and the second pier base plate 32.
In addition, the structure of the base member 30 is not limited, For example, you may form only with the pier base plate 31. FIG.

The widening member 10 includes a reinforcing base plate 12 and a rib plate 13.
As shown in FIG. 2, in this embodiment, four reinforcing base plates 12, 12,... Are arranged along the four sides of the existing pillar 3.

  As shown in FIG. 1, the reinforcing base plate 12 is a steel plate placed on the upper surface of the existing footing 4. That is, the reinforcing base plate 12 is not directly fixed to the existing footing 4, and is disposed on the existing footing 4 with the entire lower surface of the reinforcing base plate 12 in contact with the upper surface of the existing footing 4.

The end of the reinforcing base plate 12 on the existing pillar 3 side is welded A to the pier base plate 31.
The reinforcing base plate 12 does not necessarily have to be joined to the pier base plate 31.

  A plurality of mounting plates 12 a, 12 a,... Are erected on the upper surface of the reinforcing base plate 12. The lower end of the rib plate 13 is fixed to the reinforcing base plate 12 via the mounting plate 12a. Note that the mounting plate 12a may be formed as necessary. For example, when the rib plate 13 is directly joined to the upper surface of the reinforcing base plate 12, the mounting plate 12a may be omitted.

The rib plate 13 is a steel plate that connects the side surface of the existing pillar 3 and the reinforcing base plate 12.
The lower end of the rib plate 13 is fixed to the reinforcing base plate 12, and the upper portion of the rib plate 13 is fixed to the side surface of the existing pillar 3.

  The rib plate 13 is a plate material disposed along a surface perpendicular to the upper surface of the reinforcing base plate 12 and the side surface of the existing pillar 3.

  The rib plate 13 extends upward from the upper surface of the reinforcing base plate 12 in a side view, and then refracts toward the existing pillar 3. By having such a shape, the rib plate 13 joins the existing pillar 3 and the reinforcing base plate 12 without contacting the base member 30 and the anchor bolt 51 of the existing pillar 3.

The rib plate 13 is fixed to the mounting plate 12 a of the reinforcing base plate 12 via a pair of splice plates 14, 14. The pair of splice plates 14, 14 are fastened by bolts and nuts with the lower end portion of the rib plate 13 and the mounting plate 12a sandwiched therebetween.
The method for fixing the rib plate 13 to the reinforcing base plate 12 is not limited. For example, the lower end of the rib plate 13 may be welded to the upper surface of the reinforcing base plate 12.

  In the present embodiment, the rib plate 13 is fixed to the side surface of the existing column 3 via the joint member 15. The rib plate 13 may be directly fixed to the existing pillar 3.

The rib plate 13 is fixed to the joint member 15 via a pair of splice plates 14 and 14. The pair of splice plates 14 and 14 are fastened by bolts and nuts with the upper end portion of the rib plate 13 and the joint member 15 sandwiched therebetween.
The method for fixing the rib plate 13 to the joint member 15 is not limited. For example, the upper end of the rib plate 13 may be welded to the joint member 15.

Next, the construction method of the reinforcement structure 1 of this embodiment is demonstrated.
The construction method of the reinforcing structure 1 includes a preparation process, a widening member forming process, and a root-wrapping concrete placing process.

(1) Preparation Step First, as shown in FIG. 3, the existing root-wrapped concrete 34 provided around the lower end portion of the existing pillar 3 is suspended. The existing root-wrapped concrete 34 is a concrete hardened body that covers the head of the anchor bolt 51 and the base member 30.

  Although the removal method of the existing root winding concrete 34 is not limited, In this embodiment, it carries out with a water jet.

With the removal of the existing root-wrapped concrete 34, the surface of the footing 4 is removed corresponding to the position of the reinforcing base plate 12 to form a recess 41, as shown in FIG.
In addition, although the depth of the recessed part 41 is not limited, In this embodiment, it shall be about 50 mm. Further, the recess 41 has the same area as the reinforcing base plate 12.

(2) Widening member forming process First, the widening member 10 is formed by fixing the joint member 15 to the side surface of the existing column 3 as shown in FIG.
The joint member 15 is fixed to the side surface of the existing column 3 above the base member 30 (anchor bolt 51). The joint member 15 is installed in a state where a gap is left between the base member 30 and the anchor bolt 51.

The joint member 15 includes a joint flange 15a extending in the lateral direction and a plurality of joint ribs 15b, 15b,... Extending downward from the lower surface of the joint flange 15a.
The joint ribs 15 b are arranged according to the arrangement pitch of the rib plates 13.
The configuration of the joint member 15 is not limited.

  As shown in FIG. 4B, the joint member 15 is fixed to each side surface of the existing column 3 so as to surround the periphery of the existing column 3.

The joint member 15 is fixed to the existing pillar 3 and the reinforcing base plate 12 is installed.
Specifically, first, the rib plates 13, 13 are fixed to the mounting plates 12 a, 12 a disposed at both ends of each reinforcing base plate 12, and the rib plates 13, 13 are attached to both ends of the joint member 15. It fixes to the arranged joint ribs 15b and 15b.

  As shown in FIG. 5 (a), the mounting plate 12a and the rib plate 13 are fixed with bolts and nuts while the lower ends of the mounting plate 12a and the rib plate 13 are sandwiched between a pair of splice plates 14 and 14. This is done by fastening.

Similarly, the rib plate 13 and the joint rib 15b are also fixed by fastening them with bolts and nuts with the upper portion of the rib plate 13 and the joint rib 15b sandwiched between the pair of splice plates 14 and 14. Do.
The fixing method between the reinforcing base plate 12 and the rib plate 13 and the fixing method between the rib plate 13 and the joint member 15 are not limited, and may be welded, for example.

When the positioning of the reinforcing base plate 12 is determined, the reinforcing base plate 12 is welded A to the pier base plate 31 as shown in FIG. At this time, the reinforcing base plate 12 is joined to the pier base plate 31 in a state of being separated from the footing 4 (a state in which a gap is left).
Reference numeral 12b denotes a backing metal welded to the reinforcing base plate 12 in advance.

Subsequently, as shown in FIG. 6A, the widening member 10 is formed by fixing the rib plates 13, 13,.
In addition, in this embodiment, although it fixes in order from the rib plate 13 of the center side of the existing pillar 3, the fixing order of the rib plate 13 is not limited. The fixing method of each rib plate 13 at the center is the same as that of the rib plates 13 and 13 at both ends.

  When the widening member 10 is formed, as shown in FIG. 6B, the filling material 42 is filled into the recess 41 (the gap between the reinforcing base plate 12 and the footing 4) on the surface of the footing 4. In this embodiment, non-shrink mortar is employed as the filler 42. In addition, the material which comprises the filler 42 is not limited, For example, you may use grout, concrete, etc.

(4) Root-wrapped concrete placing step After curing the filler 42 filled in the recess 41 on the surface of the footing 4, the wrap-around concrete 11 is formed as shown in FIG.
The root-rolled concrete 11 is formed by placing a mold that surrounds the periphery of the widening member 10 and then placing concrete into the mold.

  The root-wrapped concrete 11 is placed in a range where at least the entire widening member 10 is hidden. In the present embodiment, the root-wrapped concrete 11 is placed up to a position that is flush with the upper surface of the joint flange 15a.

  In this embodiment, the root winding concrete 11 is installed, but the root winding concrete may be omitted.

  As mentioned above, according to the reinforcement structure 1 of the existing pier 2 of this embodiment, since the pier base plate 31 is expanded by the reinforcement base plate 12 and the bearing resistance resistance area of concrete is increased, the reinforcement effect is clear. Therefore, the highly reliable reinforcement structure 1 can be provided.

Moreover, by increasing the bearing resistance area, the neutral shaft can be moved to the compression side, and the proof stress can be effectively improved by the existing anchor bolt 51 on the tension side and the concrete bearing pressure on the compression side. .
Further, unlike the conventional reinforcing structure in which an anchor bolt is newly installed, it is not necessary to drill the existing footing 4, so that it does not interfere with the existing reinforcing bar.
Moreover, since the trouble of drilling the existing footing 4 can be omitted, the workability is excellent.

  Further, since it is not necessary to add an anchor bolt, it is possible to prevent a decrease in the adhesion resistance force of the anchor bolt due to the group effect, and overlap of the shear resistance surfaces of the existing anchor bolt 51 and the new anchor bolt. Therefore, a highly reliable reinforcement structure can be constructed.

  Further, since the reinforcing base plate 12 is joined to the pier base plate 31 of the existing pillar 3, a truss structure in which the rib plate 13 is regarded as an oblique material and the reinforcing base plate 12 is regarded as a chord material can be constructed. Therefore, the highly reliable reinforcing structure 1 is formed.

Since the base portion of the existing pillar 3 and the widening member 10 are covered with the root-wrapped concrete 11, the widening member 10 is prevented from being corroded and thus has excellent durability.
Since the contact surface between the reinforcing base plate 12 and the existing footing 4 is in close contact with the filler 41 without any gap, stress can be transmitted with certainty.

  Since the rib plate 13 is fixed to the existing pillar 3 via the joint member 15, the construction is easier than fixing the rib plate 13 directly to the existing pillar 3.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and the above-described components can be appropriately changed without departing from the spirit of the present invention.

For example, the widened area by the reinforcing base plate 12 (the widening member 10) is not limited, and may be appropriately set according to the assumed stress.
Moreover, what is necessary is just to set suitably the board thickness of each member which comprises the widening member 10, intensity | strength, etc.

  The cross-sectional shape of the existing pillar 3 is not limited to a rectangle. Moreover, the structure of the existing pillar 3 is not limited, For example, a reinforced concrete structure may be sufficient.

  Moreover, although the said embodiment demonstrated the case where the existing bridge pier 2 to which the existing pillar 3 and the existing footing 4 were fixed via the anchor frame 5 (anchor bolt 51) was demonstrated, the reinforcement structure 1 of this invention is applied. The possible existing pier structure is not limited to this. For example, you may employ | adopt as the existing pier 2 in which the existing pillar 3 and the existing footing 4 were integrally formed by the reinforced concrete.

1 Reinforcement structure (Reinforcement structure of pier)
DESCRIPTION OF SYMBOLS 10 Widening member 11 Necked concrete 12 Reinforcement base plate 12a Mounting plate 12b Backing plate 13 Rib plate 14 Splice plate 15 Joint member 15a Joint flange 15b Joint rib 2 Existing bridge pier 3 Existing pillar 31 Bridge pier base plate 32 Second pier base plate 33 Rib 34 Existing root-wrapped concrete 4 Existing footing (existing foundation)
41 Concave part 42 Filler 5 Anchor frame 51 Anchor bolt 52 Frame-like member 53 Nut A Welding

Claims (3)

A widening member retrofitted to the base of the existing column is provided, and the resistance is increased outside the existing anchor bolt that is disposed so as to surround the base of the existing column and fixes the pier base plate of the existing column to the existing footing. Therefore, without adding an anchor bolt for fixing the widening member to the existing footing, a reinforcement structure of the pier that improves the proof stress by supporting the existing anchor bolt on the tension side and the concrete on the compression side,
The widening member, characterized the reinforcing base plate is placed in a state in which the whole lower surface to the upper surface is in contact with the existing footing, and a rib plate connecting the reinforcing base plate and the side surface of the existing columns, in that it consists of , Reinforcement structure of the pier. Wherein the reinforcing base plate, characterized in that it is joined to the front Symbol pier base plate, the reinforcing structure piers according to claim 1.   The reinforcing structure for a pier according to claim 1 or 2, wherein the rib plate is fixed to the existing pillar through a joint member fixed to a side surface of the existing pillar.

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