JPH0749723B2 - Method of constructing plastic hinges on existing reinforced concrete columns - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of forming a plastic hinge on an existing reinforced concrete column in order to renovate a highly rigid existing concrete building into a seismic resistant structure. is there.

[Problems to be solved by conventional techniques and inventions] In recent years, preservation movements of existing famous buildings have become active. However, many existing buildings have a structure with high rigidity, which makes them rather susceptible to damage during an earthquake. However, there is a problem that it is difficult to save as it is.

Conventionally, as a technology to make a reinforced concrete building a seismic resistant structure, one that makes a hinge with steel or cast iron troughs, attaches this to a reinforced concrete member, reduces the rigidity of the structural member by rotating the hinge part, or changes the frame type However, this technique is difficult to implement except for new construction,
Not applied to existing buildings.

In view of the above problems, the present invention configures a plastic hinge on an existing column made of reinforced concrete in order to renovate an existing building having high rigidity to a frame structure with optimum earthquake resistance for preserving the existing building. It is intended to provide a way.

[Means for Solving the Problems]

In order to solve the above problems, the present invention provides a slit in the cross-sectional direction at a predetermined position on the outer peripheral portion of an existing column made of reinforced concrete, leaving a cross-sectional area capable of transmitting a required axial force, and a soft material that does not hinder the rotation of the column in the slit. With a short cylindrical reinforcing member circumscribing the pillar on the outer periphery of the slit portion, and filling the concrete using expansion cement between the reinforcing member and the pillar surface to form a plastic hinge It features a method of forming a plastic hinge on an existing column.

[Action]

By providing a slit in the cross-sectional direction at a predetermined position on the outer peripheral portion of the existing reinforced concrete column, leaving a cross-sectional area that can transmit the required axial force, the slit moment has a small second moment of area, and bending cracks occur here during an earthquake. Generates and becomes the hinge for the rotation of the pillar. This hinge portion forms a plastic hinge by the expansion cement filled between the short cylindrical reinforcing member and the column surface, and the restraining action due to the rattling action of the reinforcing member, and relieves the stress of the column during an earthquake. At the same time, the column axial force and shear force are safely transmitted to the lower part to protect the building from damage due to the earthquake.

〔Example〕

 The present invention will be described in detail below with reference to an embodiment shown in the drawings.

In the figure, reference numeral 1 is an existing reinforced concrete column of a building for which preserving work is to be performed. First, preserving work is to leave a cross section 1a that can transmit the required axial force at a predetermined position of the existing post 1 and slit it in a symmetrical position in the cross section on the outer periphery. 2 is cut by a diamond cutter or the like, and the slit 2 is filled with a soft material 3 that does not hinder the rotation of the column (FIGS. 1 and 2).

Next, a steel short cylindrical reinforcing member 4 circumscribing the existing column 1 is attached to the outer periphery of the slit 2 portion. The reinforcing member 4 is integrally assembled by, for example, welding arc-shaped segments divided into a plurality of pieces on site.

After that, the expansion cement 5 is filled between the reinforcing member 4 and the peripheral surface of the existing column 1 to complete the plastic hinge.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention provides a slit in the cross-sectional direction at a predetermined position on the outer peripheral portion of an existing column made of reinforced concrete, leaving a cross-sectional area capable of transmitting a required axial force, in the preservation work of the existing column having high rigidity. In addition to filling a soft material that does not hinder the rotation of the column, the short cylindrical reinforcing member circumscribing the column is attached to the outer periphery of the slit part, and concrete using expansion cement is filled between the reinforcing member and the column surface. Since a plastic hinge is constructed on an existing reinforced concrete column, the slit moment has a small second moment of area, and bending cracks occur at the time of an earthquake, which serves as a hinge for rotating the column. This hinge portion forms a plastic hinge by the expansion cement filled between the short cylindrical reinforcing member and the column surface, and the restraining action due to the rattling action of the reinforcing member, and relieves the stress of the column during an earthquake. At the same time, the column axial force and shearing force are safely transmitted to the lower part. Therefore, the building is protected from damage by the earthquake and is an effective means for preserving the existing rigid building.

[Brief description of drawings]

The drawing shows one embodiment of the present invention, FIG. 1 is a side sectional view of a state in which a slit is provided in an existing column and a soft material is filled, and FIG. 2 is a sectional view taken along the line II-II of FIG. 3 is a side sectional view of the plastic hinge in a completed state, and FIG. 4 is a sectional view taken along the line IV-IV of FIG. 1 …… Existing column, 1a …… Column cross section that can transmit required axial force, 2
…… Slit, 3 …… Soft material, 4 …… Reinforcing member, 5 ……
Expanded cement.

Claims (1)

[Claims] 1. A slit in the cross-sectional direction is provided at a predetermined position on the outer peripheral portion of an existing reinforced concrete column leaving a cross-sectional area capable of transmitting a required axial force, and the slit is filled with a soft material that does not prevent rotation of the column. A short cylindrical reinforcing member circumscribing the pillar is attached to the outer circumference of the slit portion, and a plastic hinge is formed by filling concrete using expansive cement between the reinforcing member and the pillar surface to form a plastic hinge. A method of forming a plastic hinge on an existing column.