JP4055295B2 - Seismic reinforcement method for bridge piers - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a seismic reinforcement method for bridge piers.
[0002]
[Prior art]
In general, existing reinforced concrete piers are reinforced with a steel plate around the frame to provide seismic reinforcement. However, in the case where a steel plate is wound around a wall-type reinforced concrete pier as shown in FIG. 2, the steel plate swells outward during an earthquake as shown by a virtual line in FIG. There are inconveniences such as buckling of the reinforcing bars easily occurring and shear deviation of the base of the frame easily occurring.
[0003]
In order to prevent these inconveniences, conventionally, as shown in FIG. 3 (A), a through-hole is opened in the existing pier and a through-bolt is inserted to prevent the rolled steel plate from bulging or As shown in 3 (B), an angle is installed along the lower end of the rolled steel plate and integrated by welding, and the angle is fixed to the footing by anchor reinforcing bars to improve the bending strength of the existing pier. There was a construction method.
[0004]
However, in the conventional seismic reinforcement method using the through bolts, not only the main rebar may be cut when the through hole is drilled, but in this conventional method, the column base There was a problem that shear shear could not be prevented. In addition, the latter method of welding the angle not only improves the seismic performance but also increases the bending strength, so that the seismic performance of the housing is excessively enhanced compared to the footing, and as a result, the footing is also reinforced. There were problems such as becoming necessary.
[0005]
Furthermore, as shown in FIG. 4, the wall-type reinforced concrete bridge pier generally has a main reinforcing bar as a paragraph. However, when a steel sheet is rolled up as a reinforcing method for the bridge pier in such a paragraph, the frame of the pier is used. If the adhesion between the concrete and the rolled steel sheet is not sufficient, there are problems such as incomplete paragraph and reinforcement.
[0006]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described conventional problems, and the object of the present invention is to prevent buckling of the main rebar without opening a through hole in the housing or reinforcing the footing. An object of the present invention is to provide a seismic reinforcement method for a bridge pier that can prevent shear displacement of the base of the frame and can improve the reinforcement as a paragraph.
[0007]
[Means for Solving the Problems]
The seismic reinforcement method for a bridge pier according to the present invention is a method in which a steel plate is wound around a frame of a bridge pier with a steel plate, and a steel plate is placed outside the steel plate at the base of the frame and perpendicular to the axis of the pier. while沿設, the type steel fixed to the footing of the pier by the anchor rebar, further characterized in that interpose the edge cutting material between the steel and shape steel. The mold steel is also characterized by being an H-shaped steel. Further, the edge cutting material is a cushioning material such as expanded polystyrene.
[0008]
Further, the seismic reinforcement method for the pier is a construction method in which the periphery of the pier body is rolled up with a steel plate to provide seismic reinforcement, and is characterized in that a slip prevention means is provided inside the steel plate.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 1A and 1B, reference numeral 1 denotes a wall-type reinforced concrete bridge pier, which mainly includes a wall-shaped frame 1a, a bridge seat 1b, and a footing 1c. In addition, it is good also considering the upper end part of the housing 1a as the bridge seat part 1b. Reference numeral 2 denotes a wound steel sheet, which is wound around the casing 1.
[0010]
Reference numeral 3 denotes an H-shaped steel, which is provided in a direction perpendicular to the bridge axis outside the wound steel plate 2 at the base portion of the frame 1a of the wall-type reinforced concrete pier 1. As apparent from FIG. 1C, the H-shaped steel 3 is oriented so that the flange portion 3a faces the vertical direction and the web portion 3b faces the horizontal direction. Reference numeral 4 denotes an anchor reinforcing bar, which is fixed to the footing 1c. The upper end of the anchor reinforcing bar penetrates the web portion 3b of the H-shaped steel 3, and the H-shaped steel 3 is fastened and fixed by a nut 4a.
[0011]
Reference numeral 5 denotes a cushioning material such as polystyrene foam, which is sandwiched between the wound steel plate 2 and the flange portion 3a of the H-shaped steel 3 at the base of the casing 1a of the wall-type reinforced concrete pier 1; The H-shaped steel 3 is trimmed so that the bending strength after reinforcement of the wall-type reinforced concrete pier 1 is not changed from that before reinforcement. As a result, there is no need to reinforce the footing 1c.
[0012]
Further, filling mortar 6 is injected into the gap between the H-shaped steel 3 and the footing 1c to prevent the anchor rebar 4 from being deformed in the horizontal direction.
[0013]
In FIG. 1 (D), reference numeral 7 denotes a misalignment-reinforcing bar, which is integrally attached to the back surface (pier pier 1 side) of the wound steel plate 2 by welding. The thickness, length, number, arrangement direction, density, and the like of the misalignment reinforcing bars 7 are appropriately selected and set according to the purpose. Filling mortar 8 is injected into the gap between the frame 1 a of the pier 1 and the rolled steel plate 2.
[0014]
In the said Example, although the H-shaped steel 3 is used as a shape steel which prevents the swelling of the steel plate 2, the shape steel of this invention is not limited to this, An angle (mountain steel), L-shaped steel, grooved steel, etc. Any conventional steel can be used as long as it can be fixed to the footing.
[0015]
Moreover, in the said Example, although the polystyrene foam is used as an edge cutting material of the steel plate 2 and the H-section steel 3, this invention is not limited to this, The adhesion of the H-section steel 3 and the pier 1 is eliminated. Any filling material that does not reinforce the bending strength of the pier 1 may be used.
[0016]
Furthermore, in the above-described embodiment, as a means for preventing misalignment of the wound steel plate 2, the reinforcing bar 7 is welded to the back surface of the steel plate 2, and the filling mortar 8 is injected into the gap, but the present invention is not limited to this. For example, any configuration or shape may be used as long as the steel plate 2 and the filling mortar 8 are securely and strongly integrated, such as forming a concave portion (cotter) or a convex portion on at least the back side of the steel plate 2 by pressing or the like. .
[0017]
【The invention's effect】
1) In the construction method in which the periphery of the pier frame is rolled up with a steel plate and seismic reinforced, the steel plate is installed in the direction perpendicular to the bridge axis outside the steel plate at the base of the steel frame, and the steel plate is fixed to the footing by the anchor reinforcement. In addition, since the steel plate and the steel plate are cut off, the main rebar can be prevented from buckling or the base of the housing can be prevented from shearing without opening a through-hole or reinforcing the footing. Is possible.
2) In the construction method in which the periphery of the pier frame is rolled up with steel plate and seismic reinforced, since the slip prevention means is provided inside the steel plate, the adhesion of the steel plate to the pier frame can be improved, and as a result, it can be improved as a paragraph. It becomes possible.
[Brief description of the drawings]
FIG. 1 shows an embodiment of a bridge pier according to the present invention to which seismic reinforcement is applied. FIG. 1 (A) is a view seen from the bridge axis direction, and FIG. 1 (B) is a view seen from the direction perpendicular to the bridge axis. 1C is an enlarged view of the range A in FIG. 1B, and FIG. 1D is an enlarged sectional view of the range B in FIG.
FIG. 2 is an explanatory view of the swelling of a steel sheet wound around an existing pier.
FIGS. 3A and 3B are explanatory views (A) and (B) of a conventional seismic reinforcement method.
FIGS. 4A and 4B are explanatory diagrams (A) and (B) of a pier bar arrangement.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wall-type reinforced concrete bridge pier 1a Housing 1b Bridge seat part 1c Footing 2 Winding steel sheet 3 H-shaped steel 3a Flange part 3b Web part 4 Anchor reinforcement 4a Nut 5 Buffering material 6 Filling mortar 7 Anti-slip reinforcement 8 Filling mortar

Claims (4)

In method of seismic retrofitting upright up by a steel plate precursor around the piers, an outer of the steel plate at the base of the skeleton, as well as沿設the mold steel at a right angle with respect to the pier axis, anchor the type steel A seismic reinforcement method for a pier, which is fixed to a footing of the pier by a reinforcing bar , and further, an edge cutting material is interposed between the steel plate and the steel plate.    2. The seismic reinforcement method for a pier according to claim 1, wherein the steel mold is an H steel. Seismic Retrofit for piers according to claim 1 or 2, characterized in that the edge cutting material is a cushioning material such as expanded polystyrene. 4. The method for seismic reinforcement of a pier according to claim 1, 2 or 3, characterized in that, in the construction method in which the periphery of the pier body is wound up by a steel plate and seismic reinforcement is provided, a slip prevention means is provided inside the steel plate.

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