JP4278056B2 - Seismic reinforcement structure of concrete structure and its construction method - Google Patents

Description

  The present invention relates to a seismic reinforcement structure for a concrete structure having a substantially rectangular cross section such as a column and a beam, and a construction method thereof.

Reinforcing bars and steel-framed concrete structures have been severely damaged by past earthquakes. The primary cause of the damage is the shear failure of concrete structures. It has been investigated that the cause of increasing the shear failure is a large number of alternating deformations during strong earthquakes. In order to prevent the shear failure of concrete structures such as reinforcing steel and steel concrete columns and beams and to ensure stability and stickiness of the restoring force characteristics against such repeated forces, the concrete structure is effectively restrained. Has proved to be optimal. Based on such an idea, a seismic reinforcement structure has already been implemented in which a steel plate or a fiber reinforcement sheet is wound around the outer periphery of a concrete structure to increase the shear strength. In addition, an anti-seismic reinforcement structure in which the outer periphery of a concrete structure is wound with a steel plate and mortar is filled and solidified between the steel plate and the concrete structure is also implemented.
JP-A-9-72106 JP-A-10-88822

  However, in the seismic reinforcement structure in which the surroundings of the existing concrete structure are enclosed with a reinforcing steel plate, the steel plate previously formed at the factory is brought into the site and assembled, and the joint portion is joined mainly by means such as welding. The The welding work requires skill, and the welding work in a narrow work space has poor workability, is likely to cause poor welding, and affects the quality of the seismic reinforcement structure itself. In addition, when the concrete columnar structure has a substantially rectangular cross section, there is a problem that the seismic reinforcement at the corner portion that needs to be resistant to the shear failure becomes insufficient.

  The present invention solves the problems of conventional seismic reinforcement structure of concrete structure and its construction method, excellent seismic performance, no welding work, easy on-site construction and low construction cost seismic reinforcement of concrete structure It aims at providing a structure and its construction method.

In order to solve the above-mentioned problems, the first invention has an L-shaped steel arranged at each corner of a concrete structure having a substantially rectangular cross section, and a solidified material is disposed on the outer periphery of the concrete structure containing the L-shaped steel. The circumferentially reinforced steel plates are integrally rigidly connected to each other , and the solidified material is disposed only at each corner portion .

According to a second aspect of the present invention, in the seismic reinforcement structure for a concrete structure according to the first aspect of the invention, the circumferentially reinforced steel plate is engaged at both ends and a plurality of strip steel plates having joints are joined.

According to the third aspect of the present invention , in the seismic reinforcement structure for a concrete structure according to the first or second aspect of the present invention , nuts are welded to both side surfaces of the L-shaped steel, and the circumferentially reinforced steel sheet is surrounded by a portion corresponding to the nut. An insertion hole for the direction-reinforcing steel plate mounting / interval holding bolt is formed.

According to a fourth aspect of the present invention, in the seismic reinforcement structure for a concrete structure according to any one of the first to third aspects, the circumferentially reinforced steel plate is disposed at a predetermined interval in the axial direction of the concrete structure. It is characterized by.

The fifth aspect of the present invention relates to a method for seismic reinforcement of a concrete structure, in which an L-shaped steel is bonded to each corner portion of an existing concrete structure having a substantially rectangular cross section, and the outer periphery of a concrete columnar member including the L-shaped steel is surrounded. A plurality of steel strips having meshing joints at both ends at predetermined intervals are joined to each other to install a circumferential reinforcing steel plate, and a bottom plate for the formwork is formed at the bottom of the gap between the concrete structure and the circumferential supplementary steel plate. It is characterized in that the gap portion is filled with a solidifying material such as mortar and solidified, and the concrete structure, the L-shaped steel and the circumferentially reinforced steel plate are integrally rigidly contacted.
more than

L-shaped steel is arranged at each corner portion of a concrete structure having a substantially rectangular cross section according to the present invention, and a circumferentially reinforced steel plate is integrally rigidly attached to the outer periphery of the concrete structure including the L-shaped steel via a filling solidified material. Since the L-shaped steel and the circumferentially reinforced steel plate as the reinforcing member in the corner portion are rigidly connected integrally with the existing concrete structure due to the contacted structure, the thickness of the steel plate is compared with the conventional steel-rolled reinforcing structure. The thickness can be reduced, and the reinforcement structure has excellent seismic performance.
With the configuration in which the solidifying material is disposed only at each corner, sufficient seismic performance can be obtained with a small amount of solidifying material.
By attaching a plurality of strip-shaped steel plates having joints with meshing circumferentially reinforced steel plates at both ends, the circumferentially reinforced steel plates can be easily attached to an existing concrete structure.
The existing concrete structure has a structure in which nuts are welded to both sides of the L-shaped steel in advance, and bolt insertion holes for attaching and spacing the circumferential reinforcing steel plate are formed in portions corresponding to the nuts of the circumferential reinforcing steel plate. The circumferentially reinforced steel sheet can be attached to the object at an accurate interval.
With the configuration in which the circumferential reinforcing steel plates are arranged at a predetermined interval in the axial direction of the concrete structure, sufficient seismic performance can be obtained with a small number of circumferential reinforcing steel plates.
In the construction method for seismic reinforcement of concrete structures, L-shaped steel is bonded to each corner of a concrete structure having a substantially rectangular cross section, and a predetermined interval is provided in the circumferential direction on the outer periphery of the concrete columnar member containing L-shaped steel. A circumferentially reinforced steel plate joined with a plurality of strip steel plates having meshing joints at both ends, a bottom plate is installed at the bottom of the gap between the concrete structure and the circumferentially reinforced steel plate, and a solidified material such as mortar in the gap The solid structure, the concrete structure, the L-shaped steel and the circumferentially reinforced steel plate are integrated, so welding is not required, field construction is easy, construction is possible for a short period of time, and construction costs are low. It is possible to provide a method for constructing a reinforced structure with excellent seismic performance.

  Embodiments of the present invention will be described with reference to the drawings. FIGS. 1A, 1B and 1C show an embodiment of the seismic reinforcement structure for a concrete structure of the present invention. FIG. 1 (a) is a cross-sectional view, and L-shaped steel 2 is attached to each corner portion of an existing concrete structure 1 having a substantially rectangular cross section such as columns, beams and bridge piers of reinforcing steel / steel concrete structures with an epoxy-based adhesive. Glue by etc. The L-shaped steel 2 may be a long member extending in the axial direction, or a plurality of predetermined lengths may be arranged at predetermined intervals in the axial direction. A circumferential reinforcing steel plate 3 is arranged in the circumferential direction on the outer periphery of the existing concrete structure 1 containing L-shaped steel, and a mortar or the like is provided in the gap between the existing concrete structure 1 and the circumferential reinforcing steel plate 3. The solidified material 4 is filled and solidified, and the existing concrete structure 1 having a substantially rectangular cross section, the L-shaped steel 2 that reinforces the corner portion thereof, and the circumferentially reinforced steel plate 3 are integrally rigidly connected. FIG. 1 (b) shows an embodiment in which the circumferential reinforcing steel plate 3 is arranged over almost the entire length of the concrete structure 1, and FIG. 1 (c) shows a predetermined interval in the axial direction of the concrete structure 1. The embodiment in which the circumferentially reinforced steel plate 3 is arranged is shown. Any embodiment is selected depending on the degree of reinforcement of the existing concrete structure 1.

  FIG. 2 shows an embodiment of the circumferential reinforcing steel plate 3 of the present invention. The circumferential reinforcing steel plate 3 is configured by joining a pair of U-shaped steel strips 5 having meshing joints 6 at both ends. Further, the circumferentially reinforced steel plate 3 may be formed by joining four L-shaped strip-shaped steel plates having meshing joints 6 formed at both ends. By constituting the circumferential reinforcing steel plate 3 with a plurality of strip-like steel plates 5 having meshing joints 6 at both ends, the welding operation is eliminated and the on-site joining operation is facilitated.

  FIG. 3 is an enlarged view of the meshing joint 6. The meshing joint 6 is joined to both ends of the strip-shaped steel plate 5 in advance by welding or the like. A meshing surface 6 ′ is provided on the outer peripheral surface side of one strip-shaped steel plate 5, and a meshing surface 6 ′ is provided on the inner peripheral surface side of the other strip-shaped steel plate 5, so that they can be meshed with each other.

  As shown in FIG. 4, a pair of U-shaped steel strips 5 are held at predetermined intervals in the circumferential direction on the outer periphery of an existing concrete structure 1 having a substantially rectangular cross section with an L-shaped steel 2 bonded to a corner portion. Then, the circumferential reinforcing steel plates 3 are installed by meshing the meshing surfaces 6 ′ of the meshing joints 6 at both ends. In order to accurately install and fix the existing concrete structure 1 and the circumferential reinforcing steel plate 3 at a predetermined interval in the circumferential direction, an elastic material 7 such as urethane or rubber is previously applied to a portion corresponding to the corner portion of the strip steel plate 5. Is adhered with an adhesive or the like. A pair of U-shaped strip-shaped steel plates 5 are arranged on the outer periphery of the concrete structure 1, and the meshing joints 6 at both ends are closely meshed with each other while applying tension to the strip-shaped steel plate 5 using a jack, a torque wrench or the like. At that time, the elastic material 7 such as urethane or rubber is compressed and pressed against the concrete structure 1 to firmly hold the circumferential reinforcing steel plate 3 elastically on the concrete structure 1. Furthermore, by keeping the thickness of the elastic member 7 constant, the concrete structure 1 and the circumferential reinforcing steel plate 3 also function as a spacing member that keeps a constant spacing in the circumferential direction. If a bottom plate (not shown) having a width corresponding to the gap in the circumferential direction is attached in advance to the bottom surface of the strip-shaped steel plate 5, the solidified material 4 such as mortar is attached to the gap. Can be used as a mold for filling.

  FIG. 5 shows an embodiment in which the filling of the solidified material 4 into the gap between the concrete structure 1 and the circumferential reinforcing steel plate 3 is limited to only the corner. At that time, the elastic member 7 functions as a side surface mold. Even if only the corner portion is filled with the solidifying material 4 and solidified, the concrete structure 1 and the L-shaped steel 2 and the circumferentially reinforced steel plate 3 bonded to the corner portion are integrally rigidly connected to improve the earthquake resistance. .

  FIGS. 6A and 6B show another embodiment of attaching the circumferential reinforcing steel plate 3 to the concrete structure 1. In this embodiment, nuts 8 are previously attached to both side surfaces of the L-shaped steel 2 bonded to the corner portion of the concrete structure 1 by means such as welding. A bolt insertion hole 9 is formed in a portion of the circumferential reinforcing steel plate 3 corresponding to the mounting position of the nut 8. The bolt insertion hole 9 has a large diameter in order to absorb the deviation from the mounting position of the nut 8. The circumferential reinforcing steel plate 3 is arranged on the outer periphery of the concrete structure 1, the bolt 10 is inserted from the bolt insertion hole 9, and is screwed to the nut 8, and the circumferential reinforcing steel plate 3 is attached to the concrete structure 1. The bolt 10 also functions as a gap maintaining material between the concrete structure 1 and the circumferential reinforcing steel plate 3. A seal is attached to the bolt 10 in order to prevent leakage when the solidifying material 4 such as mortar is filled.

Next, the construction method of one embodiment of the seismic reinforcement structure of the concrete structure 1 of the present invention will be described according to the procedure thereof.
(1) L-shaped steel is bonded to each corner of the existing concrete structure 1 with an adhesive or the like.
(2) A rubber-like elastic member 7 is attached at a position corresponding to the corner portion, and a pair of U-shaped strip-shaped steel plates 5 having meshing joints 6 at both ends are disposed on the outer periphery of the concrete structure 1.
(3) While the belt-shaped steel plate 5 is tensioned with a torque wrench, the meshing joint 6 of the two is meshed, the elastic material 7 is compressed and pressed against the concrete structure 1, and the circumferential reinforcing steel plate 3 is elastically held on the concrete structure 1. .
(4) A mold is placed on the bottom surface of the gap between the concrete structure 1 and the circumferential reinforcing steel plate 3, and the gap is filled with mortar.
(5) After the mortar has solidified, remove the formwork.
(6) The concrete structure, the L-shaped steel for corner portion reinforcement, and the circumferentially reinforced steel plate 3 are integrally rigidly contacted to form a reinforcing structure with high earthquake resistance.

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Explanation of symbols

1: Concrete structure 2: L-shaped steel 3: Circumferentially reinforced steel plate 4: Solidified material 5: Strip-shaped steel plate 6: Meshing joint 6 ': Meshing surface 7: Elastic material 8: Nut 9: Bolt insertion hole 10: Bolt

Claims (5)

L-shaped steel is arranged in each corner of an existing substantially rectangular cross-section of the concrete structure, the circumferential reinforcement steel through the solidifying material on the outer periphery of the concrete structure containing said L-shaped steel is rigid connection together, the Seismic reinforcement structure for concrete structures, characterized in that solidification material is placed only at each corner . The seismic reinforcement structure for a concrete structure according to claim 1 , wherein the circumferential reinforcing steel plate is configured by joining a plurality of strip steel plates having joints at both ends. A nut is welded to both side surfaces of the L-shaped steel, and insertion holes for mounting and spacing bolts for circumferential reinforcing steel plates are formed in portions corresponding to the nuts of the circumferential reinforcing steel plates. Item 3. An earthquake-proof reinforcement structure for a concrete structure according to item 1 or 2 . Seismic reinforcement structure of the concrete structure according to any one of claims 1 to 3, characterized in that the circumferential-direction reinforcement steel is disposed at a predetermined interval in the axial direction of the concrete structure. A plurality of strips having L-shaped steel bonded to each corner of an existing concrete structure having a substantially rectangular cross section and meshing at both ends at predetermined intervals in the circumferential direction of a concrete columnar member containing L-shaped steel. A steel plate is joined and a circumferential reinforcing steel plate is installed. A bottom plate for a formwork is installed at the bottom of the gap between the concrete structure and the circumferential supplementary steel plate. The gap is filled with a solidifying material such as mortar and solidified. A method for constructing a seismic reinforcement of a concrete structure, characterized in that a concrete structure, an L-shaped steel and a circumferentially reinforced steel plate are integrally rigidly connected.

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