JPH0971910A - Reinforcement method for cylindrical structures - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To provide a structural system in which a reinforcing structure is integrated with an existing structure and a load is loaded from a normal load state and the displacement itself is actively suppressed. SOLUTION: On the surface of a cylindrical structure 1, a strip-shaped precast concrete pilaster long in the axial direction of the cylinder is attached by backfilling concrete thickness separated from the surface of the structure, and a large number of PC tension members 3 are attached to the surface of the structure. And the pillars 5 are horizontally arranged, the ends of the PC tension members 3 are inserted so as to intersect in the pillars 5, the formwork 8 is assembled between the adjacent pillars, and the backfill concrete 4 is filled. Then, after curing, the PC tension material is tensioned and fixed to the pilaster 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reinforcing a columnar structure having a circular, oval or elliptical cross section, for example, a columnar structure such as a pier or a column.

[0002]

[Prior Art] The Hanshin catastrophe causes a problem in seismic resistance of piers and columns of buildings, and it is urgent to revise the seismic resistance standards of structures and to reinforce existing structures constructed according to the existing seismic standards. Has become an issue. As a method of reinforcing existing structures, for example, in the case of piers, a method of winding concrete on the surface of the existing pier, a method of adhering sheet-shaped carbon fiber etc. to the outer surface of the structure, or a thin steel plate is used. It is done by winding the outer surface.

However, although it is easy to wind up concrete, bond carbon fiber sheets, wind up steel plate, etc., the reinforcement of these is only applied to the reinforcing material after an excessive load acts on the structure and deformation occurs. It is a structural system in which the load transitions, and does not reinforce before the structure is deformed. Further, since the reinforcing structure is not integrated with the reinforcing portion, there is a problem that it is unclear whether or not the reinforcing structure is kept integrated with the structure for a long period of time.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a reinforcing method having a structural system in which a reinforcing structure is integrated with an existing structure so as to bear a load even under a normal load condition and positively suppress displacement itself. The purpose is to do.

[0005]

According to the present invention, a large number of elongated precast concrete pilasters are attached vertically to the outer periphery of a columnar structure with a backfilling concrete layer space provided, and a large number of circumferential lines are provided in the concrete layer. A method for reinforcing a columnar structure is characterized in that a direction PC tension material is arranged, and after the backfilling concrete is placed, the PC tension material is tensioned and the end thereof is fixed to the pilaster. A more specific description is as follows.

On the surface of the existing columnar structure, the PC is divided into a plurality of positions evenly in the circumferential direction and has a width shorter than the divided circumference.
A strip-shaped precast concrete pilaster (hereinafter simply referred to as pilaster) that is long in the axial direction of the cylinder and has a tension material insertion sheath and a fixing structure is installed vertically from the surface of the structure with the thickness of the backfill concrete separated. Half or one round of PC tension material is placed horizontally between the front surface of the structure and the back surface of the Pilaster,
Insert the PC tension material end so that it intersects in the Pilaster, and
C Allow the working length of the tension material to protrude from the pilaster. A mold is assembled between adjacent pillars, and concrete or mortar is filled between the back surface of the mold and the back surface of the pillar and the surface of the structure. After the concrete or mortar hardens,
The reaction force is applied to the pillar and the PC tension member is tensioned to apply a compressive force toward the center of the existing columnar structure to reinforce the structure.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An example of covering and reinforcing the above-ground portion 5m of a pier, which is a cylindrical structure 1 having a diameter of 3m, will be described. 1 is a sectional view thereof, and FIG. 2 is a perspective view thereof. Pilaster 5 used for this reinforcement has a width of 50 cm, a length of 2.5 m, and a thickness of 12.
cm, the weight was about 350 kg, and a member having a slightly concave surface on the back side in the width direction was manufactured as a factory product. The outer circumference of the columnar structure 1 was about 9.42 m, and eight pillars 5 were used per structure.

The interval between the insertion holes of the PC tension member 3 was built in the pilaster as a pitch of 25 cm in the vertical direction. Note that P
The fixing positions of the C-tension material 3 are distributed to the eight pilasters 5, but the pilasters 5 are all manufactured with the same specifications in order to have versatility. As shown in FIG. 3, the surface of the cylindrical structure 1 is marked out, holes 8 for mounting anchors of the eight pillars 5 are bored, and the hole-in anchors 11 are inserted and fixed.

The vertical reinforcing bars 2 are assembled around the cylindrical structure 1, and the pilasters 5 brought in from the factory are temporarily fixed to the hole-in anchors 11 installed at predetermined positions, respectively, and the thickness of the backfill concrete 4, that is, The spacing between the front surface of the columnar structure 1 and the back surface of the pillar is adjusted to 20 cm, and the nuts 12 and 13 are fixed. The PC tension member 3 is arranged at 360 degrees (Fig. 4), and the pillar tensioner 5 that is properly fixed is changed depending on the horizontal step position so that the decrease in tension force is not concentrated by friction, and the PC tension member 3 (1T12.7PC strand) is inserted. did.

The vertical formwork 8 is assembled between the pilasters and the backfill concrete 4 is placed. Backfill concrete 4
When is hardened, the form 8 is removed, and two tension jacks are attached to the PC tension member 3 which projects from the pilaster 5 so as to be tensioned. After that, grout is injected into the sheath duct of the PC tension material 3, and the fixing portion 14 and the unused fixing hole of the PC tension material 3 are filled up afterwards to complete the reinforcement.

Although eight pilasters are used in this example,
It is not limited to this, and can be appropriately selected depending on the diameter of the structure. Due to the balance between the width of the pillar and the distance between the adjacent pillars, and the pillars protruding from the surface, the cylindrical structure after finishing gives a slender feeling (slender aesthetic feeling) and also produces a landscape effect.

Further, it is preferable that the winding angle of the PC tension member (center angle of the columnar structure) is also appropriately set according to the diameter of the structure and the number of pilasters used. The precast concrete pilaster used in the reinforcing method of the present invention has backfilled concrete interposed, the surface may be a straight surface, and the concave surface of the back surface does not need to be strictly adjusted to the outer diameter of the structure, so that a wide range of structures can be constructed. It can be used for outer diameters. Regarding the length, it is also possible to manufacture a standard one, match it with the actual one, and cut and combine it. There is also an advantage that the cost can be reduced by mass-producing multiple sizes in the factory.

Although the above-mentioned embodiment describes a columnar structure having a perfect circular cross section, the present invention can be applied to a structure having an elliptical cross section.

[0014]

According to the reinforcing method of the present invention, the reinforcing effect does not appear after the structure is displaced, but it is a suitable reinforcing method that is integrated with the structure itself. In the present invention, by using the precast pillars that can be mass-produced, the reassembling of the reinforcing bar and the formwork can be minimized, and the reinforcement is easy. Furthermore, with this method, vertical striped accents were created on the surface of the post-construction pillar, and it was possible to obtain an excellent landscape that could be mistaken for a new structure, which is aesthetically pleasing and solidly reinforced. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example.

FIG. 2 is a perspective view of an example.

FIG. 3 is a detailed view of a mounting portion of the embodiment.

FIG. 4 is a detailed view of a fixing unit according to the exemplary embodiment.

[Explanation of symbols]

1 Cylindrical Structure 2 Reinforcing Bar 3 PC Tensile Material 4 Concrete 5 Pilaster 6 Hole 8 Formwork 11 Hole In Anchor 12 Nut 13 Nut 14 Anchoring Section

Claims (1)

[Claims] 1. A backfilling concrete layer space is provided on the outer periphery of a columnar structure, and a large number of elongated precast concrete pillars are attached to the top and bottom, and a large number of circumferential PC tension members are arranged in the concrete layer. Then, the method for reinforcing a columnar structure is characterized in that after the backfilling concrete is placed, the PC tension material is tensioned and the end thereof is fixed to the pilaster.