JP2006183320A - Reinforcing structure and reinforcing method of corner part of existing steel pier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method capable of surely reinforcing a corner part of an existing steel pier, without causing the problem of a construction limit and an aesthetic appearance. <P>SOLUTION: When reinforcing the corner part 13 made of a column part 11 and a beam part 12 of the existing steel pier 10, two steel braces 21 are arranged in a crossing shape inside respective steel box girders 19 for constituting the beam part 12. The mutual braces 21 and 21 of the adjacent steel box girders 19 and 19 are connected so that force can be transmitted. A connecting body 21S of these braces 21, 21, etc. is constructed so as to range over the total length of the beam part 12 including the corner part 13. A stress transmitting device 20 capable of transmitting a load operating on the beam part 12 in the longitudinal direction, is constituted of this brace connecting body 21S. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for reinforcing a corner portion of an existing steel pier, and more particularly to a reinforcement method suitable for a steel pier having a box-shaped cross section.

The corner portion formed by the column portion and the beam portion of the steel pier has a large shear lag stress (shear delay) (see FIG. 7A). Therefore, stress concentration occurs at both ends of the joint portion between the column portion and the beam portion in the corner portion, and fatigue cracks are easily generated. Therefore, various reinforcing methods have been proposed conventionally (see Patent Documents 1 to 3 below).
For example, in Patent Document 1 and Japanese Patent Application Laid-Open No. 2003-049404, a prestressed steel material is slanted from the outer surface of the beam portion to the outer surface of the column portion. This prestressed steel material bypasses the flow of force from the beam portion to the column portion, thereby mitigating the shear delay at the corner portion and preventing the occurrence of fatigue cracks or suppressing the growth.
In Patent Document 2 (Japanese Patent Application Laid-Open No. 2003-049410), concrete is loaded at a corner defined by the outer side surface of the column part and the outer side surface of the beam part.
In Patent Document 3; Japanese Patent Application Laid-Open No. 2004-068402, a steel plate is installed so as to straddle from the outer surface before and after the column part to the outer surface before and after the beam part, and is subjected to thermal prestress.
JP2003-049404 JP 2003-049410 A JP-A-2004-068402

In the conventional methods disclosed in Patent Documents 1 to 3, the reinforcing structure appears outside the pier, and there is a problem of ensuring aesthetics. Moreover, construction will be restricted if it gets caught in the construction limit. Manholes, drain pipes, etc. may be provided on the outer wall of the location to be installed.
Further, the reinforcing device is arranged only at the corner portion, and the path of the force and the stress state are adjusted only at the corner portion, and the state where the stress is transmitted to the corner portion is not changed. Moreover, in the case of prestressed steel, it is suitable for the corners of a to-shape or a cross shape, but is difficult to install on the outer side of the corners of a T-shape or a Γ-shape.

In order to solve the above-mentioned problems, the present invention is a reinforcing structure of a corner portion formed by a column portion and a beam portion of an existing steel pier, and can transmit a load acting on the beam portion or the column portion in a longitudinal direction. A stress transmission device made of an elongated steel member is provided so as to be continuous over substantially the entire length or an equivalent length of the beam portion or the column portion including the corner portion. Further, the present invention is a method for reinforcing a corner portion formed by a column portion and a beam portion of an existing steel pier, and is a stress transmission composed of an elongated steel member capable of transmitting a load acting on the beam portion or the column portion in a longitudinal direction. The device is provided so as to pass through a portion where the stress at the corner portion is not concentrated and to be continuous over substantially the entire length or the equivalent length of the beam portion or the column portion.
As a result, a bypass path of force can be provided in the longitudinal direction of the beam portion or the column portion, and not only the shear delay at the corner portion can be reduced, but also the load can be distributed in the longitudinal direction of the beam portion or the column portion. As a result, the corner portion can be further reinforced. Moreover, there is no restriction | limiting in the shape of a corner part, It can apply also to a T-shaped and a Γ-shaped corner part as well as a square-shaped part and a cross-shaped corner part. When the existing steel pier has a box-shaped cross section, it is desirable to provide the stress transmission device inside a beam section or a column section of the box cross section. This eliminates the problems of architectural limitations and aesthetic degradation.

Here, the stress transmission device is arranged in a row along the beam portion or the column portion, and a plurality of brace-like steel elongated members in which adjacent members are inclined in opposite directions and connected to be able to transmit force. It is desirable to become.
Thereby, force transmission and dispersion can be effectively performed.

The stress transmission device includes a plurality of brace-like steel elongated members arranged in a line along the beam portion or the column portion, and adjacent members that are inclined in opposite directions and connected to be able to transmit force. 2nd which consists of a brace continuous body and the other several brace-like steel elongated members arranged in parallel with this 1st brace continuous body, and the adjacent things incline in the reverse direction mutually and were connected so that force transmission was possible. It is more preferable that the brace-like steel elongated members including the brace continuum and disposed at the same position in the first and second brace continuums are inclined in directions opposite to each other.
As a result, force transmission and dispersion can be performed more effectively.

Each of the brace-like steel elongated members is disposed along a diagonal line of a longitudinal cut surface of the steel box girder constituting the beam part or the column part (that is, a diagonal line in front view or side view of the steel box girder). It is desirable that
The end of each brace-shaped steel elongated member is preferably connected and fixed to the inner surface of the beam or column. It is desirable that end portions of adjacent brace-like steel elongated members are connected to substantially the same position on the inner surface of the beam portion or the column portion. As a result, it is desirable that the ends of the adjacent brace-shaped steel elongated members are directly connected structurally.
A connecting member may be fixed to the inner surface of the beam portion or the column portion, and an end portion of the brace-like steel elongated member may be connected to the connecting member.
A pair of the connecting members are connected to one end and the other end of the adjacent brace-like steel elongated members, respectively, and these connecting members constitute the steel box girder that constitutes the beam portion or the column portion. It is desirable that the diaphragms are connected to each other with the diaphragm interposed therebetween.

  According to the present invention, a force bypass path can be provided in the longitudinal direction of the beam portion or the column portion, and not only can the shear delay at the corner portion be reduced, but also the load can be distributed in the longitudinal direction of the beam portion or the column portion. As a result, the corner portion can be further reinforced. A stress transmission device can be arranged inside the beam section or the column section of the box-shaped cross section, thereby eliminating the problems of architectural limitations and aesthetic deterioration.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 schematically illustrate an example of an existing steel pier 10. The steel pier 10 has a vertical column portion 11 and a horizontal beam portion 12 provided horizontally at the upper end portion of the column portion 11 and has a T shape. Both the column portion 11 and the cross beam portion 12 are configured by connecting a plurality of steel box girders 19 and have a box-shaped cross section. A corner portion 13 (a portion surrounded by a circle in FIG. 2) is formed by intersecting the column portion 11 and the cross beam portion 12.

FIG. 7A shows the stress distribution in the joint line 13a (see FIG. 1) between the column portion 11 and the upper flange 19f of the cross beam portion 12 in the corner portion 13 before reinforcement by the method of the present invention. is there. When a load is applied to the cross beam portion 12, a large stress concentration appears at both ends of the joining line 13a. For this reason, fatigue cracks are easily generated and propagated from both ends.
As shown in FIG. 1, in order to reinforce the corner portion 13, a stress transmission device 20 is provided in the transverse beam portion 12 along the longitudinal direction of the transverse beam portion 12. As shown by the broken line in FIG. 7B, this stress transmission device 20 is a portion where stress is not concentrated on the joint line 13a before reinforcement, that is, an intermediate portion (preferably just the center of the joint line 13a or its vicinity. ) And is disposed on a vertical plane (longitudinal cut surface) along the longitudinal direction of the cross beam portion 12.

  As shown in FIGS. 1 to 3, the stress transmission device 20 includes a large number of steel braces 21 (brace-like steel elongated members) made of a shape steel such as H-section steel (FIG. 4) as a main component. . These steel braces 21 are arranged for each steel box girder 19 constituting the cross beam portion 12. At the time of installation work, manholes 11h and 12h provided on the outer surface of the pillar portion 11 and the cross beam portion 12 of the existing bridge are opened, and the steel brace 21 is inserted into the cross beam portion 12 from there. Furthermore, it distributes in each steel box girder 19 through the manhole 19h of each diaphragm 19d in the beam portion 12.

  Each steel brace 21 is diagonally viewed from the upper left corner (or lower right corner to upper right corner) near the center in the width direction (bridge axis direction) in each steel box girder 19 (diagonal line in the longitudinal direction cut surface) Arranged). Both ends of the steel brace 21 are connected and fixed to the corners of the steel box girder 19, respectively. In each steel box girder 19, two steel braces 21 and 21 are arranged in an X-shaped cross (inclined in opposite directions).

  The two steel box girders 19, 19 that are V-shaped or Λ-shaped (inclined in opposite directions) in the two adjacent steel box girders 19, 19 are connected to each other between the two steel box girders 19, 19 Are directly connected structurally. In other words, the lower left end portion of the steel brace 21 rising to the right of the adjacent steel box girder 19 is connected to the lower right end portion of the lower steel brace 21. The upper right end of the steel brace 21 rising to the right is connected to the upper left end of the lower steel brace 21 of the adjacent steel box girder 19.

In this way, a continuous body 21S of a large number of steel braces 21, 21... Continues from one end to the other end in the longitudinal direction (bridge width direction) of the cross beam portion 12. As shown in FIG. 3, the brace continuum 21 </ b> S is provided in two rows corresponding to the crossing of the two steel braces 21 and 21 in each steel box girder 19. The stress transmission device 20 is configured by the two rows of brace continuums 21S and 21S.
When one of the brace continuums 21S and 21S is a “first brace continuum”, the other is a “second brace continuum”.

The detailed structure of the connecting portion between the two steel braces 21 and 21 will be described. FIG. 4 shows an example of the connecting member 22 used for this connection. The connecting member 22 is made of steel and includes a bottom plate 22a, a back plate 22b, and a standing plate 22c that are orthogonal to each other. As shown in FIGS. 4 and 5, the connecting member 22 bottom plate 22 a is applied to the inner surface of the lower flange 19 f of the steel box girder 19 and connected by a high-strength bolt. And the edge part of the web 21w of the steel brace 21 is piled up on the standing board 22c, and it connects with the high strength volt | bolt 23. FIG. As a result, the steel brace 21 is connected to the pier 10 via the connecting member 22. The end portions of the pair of flanges 21f of the steel brace 21 may be cut in advance by an appropriate length so as not to interfere with the connecting member 22.
In the example of FIGS. 4 and 5, the web 21w of the steel brace 21 is erected and the flanges 21f and 21f are positioned above and below the web 21w. However, as shown in FIG. The web 21w may be set sideways and the flanges 21f and 21f may be erected, and the end of the flange 21f of the steel brace 21 may be brought into contact with the upright plate 22c of the connecting member 22 for connection. In the embodiment of FIG. 6, when the end of the other flange 21f (near side) obstructs the fastening of the high-strength bolt 23, it may be cut off to an appropriate length.

  4 to 6 show only the connection structure of the lower end of the steel brace 21, the upper end is the same. The connecting member 22 for the upper end is applied to and connected to the inner surface of the upper flange 19f of the steel box girder 19.

  The back plate 22 b of the connecting member 22 is applied to the diaphragm 19 d of the steel box girder 19. The back plate 22b of the connecting member 22 for the steel brace 21 in the adjacent steel box girder 19 is applied to the opposite side of the diaphragm 19d. The back plates 22b and 22b of these two connecting members 22 and 22 are connected by a high strength bolt 23 with the diaphragm 19d interposed therebetween. Thereby, the two steel braces 21 are connected so that stress can be transmitted almost directly. As a result, the stress transmission device 20 can transmit stress over the entire length.

As a result, a stress transmission bypass path along the longitudinal direction is formed inside the beam portion 12. Therefore, as shown in FIG. 7B, the stress concentrated on both ends of the joint line 13a between the beam portion 12 and the column portion 11 at the corner portion 13 can be distributed to the central portion of the joint line 13a. The shear delay on the line 13a can be reduced. Moreover, since the stress transmission device 20 extends not only in the corner portion 13 and its periphery but also over the substantially entire length of the beam portion 12, the load can be distributed over substantially the entire beam portion 12. The degree of concentration can be relaxed. As a result, the corners can be reinforced more reliably, and the effect of preventing the occurrence of fatigue cracks or suppressing the progress can be reliably exhibited.
Since the stress transmission device 20 is accommodated in the pier 10, the architectural limit is not violated and the aesthetic appearance is not impaired.

Next, another embodiment will be described. In the following embodiments, the same reference numerals are given to the drawings for the same components as those in the first embodiment, and the description thereof is omitted.
As shown in FIG. 8, a steel brace 21 may be provided not only on the cross beam portion 12 of the pier 10 but also on the column portion 11. In this case, the steel braces 21 of the corner portions 13 are connected to each other, and the steel braces 21 of the column portions 11 are connected to each other to form a brace continuous body 21S.
As shown in FIG. 9, the stress transmission device 20 is provided only in a region of a certain length including the corner portion 13, not the entire length of the lateral beam portion 12, so as not to reach the end of the lateral beam portion 12. Also good.

The reinforcing structure of the present invention can be applied to various piers having a box-shaped cross section.
A bridge pier 10X shown in FIG. 10 has a pair of column portions 11 provided on the left and right sides, and a horizontal beam portion 12 is bridged between the pair of column portions 11 and 11, thus forming a generally square shape. Therefore, two corner portions 13, 13 are formed on the left and right. By constructing the stress transmission device 20 including the steel brace 21 over the entire length of the cross beam portion 12 of the bridge pier 10X, the two corner portions 13 and 13 can be reinforced. Corresponding to two steel braces 21 and 21 being arranged crossing each box girder 19, two brace continuums 21S and 21S are provided in the entire pier 10X, and these two brace continuums are provided. The stress transmission device 20 is configured by 21S and 21S.
In addition, you may decide to provide the steel braces 21 to a pair of pillar part 11 of this pier 10X similarly to FIG.

A bridge pier 10Y shown in FIG. 11 has a horizontal beam portion 12A bridged between intermediate portions of a pair of left and right column portions 11, and a horizontal beam portion 12B provided in a cantilever shape outward from the upper end portion of each column portion 11. . Steel braces 21 are provided on the entire length of the intermediate cross beam portion 12A and the entire lengths of the left and right cantilevered horizontal beam portions 12B, and the steel braces are also provided between the upper end of each column portion 11 and the intermediate cross beam portion 12A. 21 is provided.
The cantilevered horizontal beam portion 12B and the steel brace 21 of the column portion 11 are connected to each other via a steel brace 21 at the corner portion 13 at the upper left and right ends. The column 11 and the steel braces 21 of the intermediate cross beam portion 12A are connected to each other through a steel brace 21 at the corner portion 13 of the intermediate portion. As a result, a series of brace continuums 21 </ b> S are formed across the pair of cantilevered horizontal beam portions 12 </ b> B, the upper half of the pair of column portions 11, and the intermediate horizontal beam portion 12 </ b> A. Corresponding to two steel braces 21 and 21 being arranged crossing each box girder 19, two brace continuums 21S and 21S are provided in the entire pier 10Y, and these two brace continuums are provided. The stress transmission device 20 is configured by 21S and 21S.
In addition, you may decide to provide the steel braces 21 also in the lower half of the column part 11 of this pier 10Y.

As shown in FIG. 12, each steel box girder 19 may be provided with only one steel brace 21, and the entire pier 10 may have only one brace continuum 21 </ b> S.
As shown in FIG. 13, the steel brace 21 may be arranged shifted from the central axis of the cross beam portion 12. In this case, it is preferable to provide the two continuous bodies 21S at an equal distance from the central axis.

The present invention is not limited to the above embodiment, and various modifications can be made.
The connecting means between the steel box girder 19, the connecting member 22, and the brace 21 may be welding instead of the high-strength bolt.
The elongated steel member constituting the stress transmission device 20 may not be a brace shape, but may be horizontal along the beam portion 12 or may be vertical along the column portion 11.
As the steel elongated member, a shaped steel assembled by rolling or welding or a elongated steel material other than the shaped steel can be used. Instead of the H-shaped steel shown in the above embodiment, other shaped steels such as T-shaped steel and L-shaped steel, and steel elongated members other than the shaped steel may be used. The steel elongated member may be assembled by welding.

  The present invention can be applied to reinforce the piers of existing bridges.

It is a perspective view which shows the reinforcement structure of the steel bridge pier which concerns on 1st Embodiment of this invention. It is a front view of the said steel pier. It is a top view of the said steel pier. It is a perspective view which shows an example of the connection structure of the edge part of the steel brace of the said reinforcement structure, a connection means is shown as a continuous line, a steel brace and a steel box girder are shown with a virtual line, and a high strength bolt is abbreviate | omitted is there. It is a front view of the said connection structure. It is a perspective view which shows the modification of the connection structure of FIG. It is a stress distribution figure on the joining line of the column part in a corner part, and an upper flange of a cross beam part, (a) shows the state before reinforcement by the present invention, and (b) shows the state after reinforcement by the present invention. Show. It is a front view which shows the modification of a reinforcement structure. It is a front view which shows the other modification of a reinforcement structure. It is a front view which shows embodiment which applied the reinforcement structure to the steel bridge piers of another structure. It is a front view which shows embodiment which applied the reinforcement structure to the steel bridge pier of another structure. It is a front view which shows the modification of a reinforcement structure. It is a front view which shows the modification of a reinforcement structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Steel pier 11 Pillar part 11h Manhole 12 Cross beam part 12h Manhole 12A, 12B Cross beam part 13 Corner corner part 13a Joining line of corner part and column part 19 Steel box girder 19f Flange 19d Diaphragm 19h Manhole 20 Stress transmission Device 21 Shaped steel brace (Brass-like steel elongated member)
21f Flange 21w Web 21S Brace continuum 22 Connecting member 22a Bottom plate 22b Back plate 22c Standing plate 23 High strength bolt

Claims (5)

  This is a reinforcing structure of the corner part formed by the column part and the beam part of the existing steel pier with a box-shaped cross section, and the stress comprising the elongated steel member capable of transmitting the load acting on the beam part or the column part in the longitudinal direction. A reinforcing structure for a corner portion of an existing steel pier, wherein the transmission device is provided so as to be continuous over substantially the entire length or an equivalent length of a beam portion or a column portion including the corner portion.   The stress transmission device is composed of a plurality of brace-like steel elongated members that are arranged in a line along the beam portion or the column portion and in which adjacent members are inclined in opposite directions and connected to be able to transmit force. The corner part reinforcement structure of Claim 1 characterized by the above-mentioned.   The stress transmission device includes a plurality of brace-like steel elongated members arranged in a line along the beam portion or the column portion, and adjacent members that are inclined in opposite directions and connected to be able to transmit force. 2nd which consists of a brace continuous body and the other several brace-like steel elongated members arranged in parallel with this 1st brace continuous body, and the adjacent things incline in the reverse direction mutually and were connected so that force transmission was possible. The brace-like steel elongated members including the brace continuum and disposed at the same position in the first and second brace continuums are inclined in opposite directions to each other. The described corner reinforcement structure.   Each of the said brace-shaped steel elongate member is arrange | positioned along the diagonal of the longitudinal direction cut surface of the steel box girder which comprises the said beam part or a column part, The Claim 2 or 3 characterized by the above-mentioned. The corner reinforcement structure.   A method of reinforcing a corner portion formed by a column portion and a beam portion of an existing box-shaped steel bridge pier, which includes a steel elongated member capable of transmitting a load acting on the beam portion or the column portion in a longitudinal direction. A corner of an existing steel pier, wherein a stress transmission device is provided so as to pass through a portion where the stress at the corner portion is not concentrated and to be continuous over substantially the entire length or an equivalent length inside the beam portion or the column portion. How to reinforce corners.

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