JP6901980B2 - Steel corner stopper embedded part reinforcement structure and method - Google Patents

Description

The present disclosure relates to a steel square stopper embedded portion reinforcing structure and method.

Conventionally, reinforced concrete structures made of reinforced concrete have been widely used as railway structures such as viaducts. In such railway structures, stoppers are used to connect the rigid frame viaduct or pier, which is a substructure, to the bridge girder, which is a superstructure placed on the substructure. The functions required of the stopper are to limit the movement of the bridge girder caused by the vibration at the time of an earthquake and the lateral pressure of the train, to prevent the bridge collapse of the bridge girder, and the like. The stopper needs to have high rigidity enough to limit the movement of the bridge girder, and it is desirable to maintain the rigidity enough to limit the displacement even after an earthquake in consideration of aftershocks. Therefore, a steel square stopper in which a square steel pipe is filled with concrete is used (see, for example, Patent Document 1).

FIG. 1 is a perspective view showing an example in which a conventional steel angle stopper is applied to a connecting portion between a substructure and a superstructure.

In the figure, reference numeral 21 denotes a viaduct girder, which is made of reinforced concrete, and a railroad track, that is, a track 25 is laid on the upper surface thereof. Reference numeral 11 denotes a viaduct pier, which is made of reinforced concrete and supports the bridge girder 21. Specifically, the girder end 22 of the bridge girder 21 is placed on the girder seat upper surface 12a of the girder seat 12 formed at the upper end of the pier 11. Further, as shown in the figure, between the girder seat upper surface 12a and the girder end lower surface 22a, a girder seat 13 formed on the girder seat upper surface 12a and a rubber shoe 26 placed on the girder seat 13 are placed. It is desirable to intervene. In the figure, for convenience of explanation, a part of the girder end 22 of the bridge girder 21 is omitted.

Further, in order to limit the horizontal movement of the bridge girder 21 caused by the vibration at the time of an earthquake or the lateral pressure of the train, the lower part of the steel square stopper 31 in which the square steel pipe is filled with concrete is embedded in the girder seat 12, and the steel is said. The upper part of the square stopper 31 is inserted into the girder end 22 with a gap fit. As shown in the figure, it is desirable that a plurality of the steel angle stoppers 31 (two in the example shown in the figure) are arranged so as to be arranged in the width direction of the bridge girder 21. Further, a gap 24, which will be described later, exists between the girder seat upper surface 12a and the girder end lower surface 22a, and the intermediate portion of the steel angle stopper 31 is exposed to the gap 24.

Since the steel angle stopper 31 having high rigidity is arranged in this way, the horizontal movement of the bridge girder 21 with respect to the pier 11 is appropriately restricted.

JP-A-2017-0445885

However, in the above-mentioned conventional technique, when a large impact is received as in the case of an earthquake, the girder seat 12 as a substructure in which the lower end of the steel angle stopper 31 and its vicinity are embedded may be damaged. is there.

FIG. 2 is a photograph showing the damage caused by the earthquake to the substructure in which the conventional steel angle stopper is embedded, and FIG. 3 is a schematic showing the connection portion between the substructure in which the conventional steel angle stopper is embedded and the superstructure. Side perspective view, FIG. 4 is a two-view view illustrating damage to the substructure in which the conventional steel angle stopper is embedded, and FIG. 5 is a two-view view illustrating the stress acting on the substructure in which the conventional steel angle stopper is embedded. It is a schematic side perspective view. In FIG. 2, (a) is a photograph showing the entire girder, (b) is an enlarged photograph of the arrow indicating portion of (a), and in FIG. 4, (a) is a schematic top perspective view, ( b) is a schematic front perspective view.

As shown in FIG. 2, when the girder seat 12 is damaged, inspection using an aerial work platform is required, which requires time and labor. Moreover, since the work space for performing the restoration work is narrow, not only the restoration takes a long time, but also the restoration work itself may become difficult.

Generally, the steel angle stopper 31 is attached as shown in FIGS. 3 and 4. As shown in FIG. 3, the lower end of the steel angle stopper 31 and its vicinity are embedded in the girder seat 12, and the upper end of the steel angle stopper 31 protruding upward from the girder upper surface 12a and its vicinity are the girder end lower surface 22a. It is inserted and accommodated by a gap fit in the upper accommodating cavity 23 which is a cavity extending in the vertical direction formed at the girder end 22 so as to open to. That is, the upper end of the steel angle stopper 31 and its vicinity are fitted with a horizontal tolerance with respect to the upper accommodating cavity 23. Further, a plurality of reinforcing reinforcing bars 33 are embedded in the girder seat 12 made of reinforced concrete so as to cover the side of the steel angle stopper 31 facing the front surface 12b of the girder seat. As shown in FIG. 4, the reinforcing bars 33 have a first reinforcing bar 33a having a substantially U-shaped shape as viewed from the upper surface of the girder seat 12a and a third reinforcing bar 33 having a substantially U-shaped shape as seen from the upper surface of the girder seat 12a. 2 Reinforcing reinforcing bars 33b are included. The reinforcing reinforcing bars 33 are arranged side by side in the vertical direction so as to form a plurality of layers (7 layers in the example shown in the figure).

However, when a large force G acts on the bridge girder 21 as in an earthquake, the portion of the steel angle stopper 31 housed in the upper accommodating cavity 23 formed at the girder end 22 is subjected to the inertial force F of the bridge girder 21. Will receive. When the inertial force F is large, shear failure occurs in the girder seat 12 in which the lower end of the steel angle stopper 31 and its vicinity are embedded, and the shear failure surface 14 as shown by the dotted line in FIGS. 3 and 4 is formed. It may occur.

When an inertial force F acts on the steel angle stopper 31 embedded in the girder seat 12, the reaction force inside the girder seat 12 is as shown by a dotted arrow in FIG. A horizontal stress distribution σ occurs (see, for example, Non-Patent Document 1). Then, a horizontal resultant force f1 acts on the front surface 12b side of the girder seat of the steel angle stopper 31, and a horizontal resultant force f2 acts on the rear surface 12c side of the girder seat, and the resultant force f1 intersects the shear fracture surface 14. The reinforced reinforcing bar 33 and the concrete of the shear fracture surface 14 bear the burden.
Dai Okamoto, Tsutomu Sato, Toshiya Tadokoro, Shuhei Matsueda, "Effect of embedding length on the yield strength of steel angle stopper", JSCE 64th Annual Academic Lecture Summary, CS2-021, 2009.9

Here, by solving the problems of the conventional technique and applying prestress to the concrete structure in which the steel angle stopper is embedded, the horizontal stress generated in the concrete structure is reduced, and the concrete It is an object of the present invention to provide a steel square stopper embedded portion reinforcing structure and method capable of improving the durability of a structure.

Therefore, in the steel angle stopper embedded reinforcement structure, and concrete structure is a substructure, at least the lower end is embedded in the concrete structure, at least the upper end, projecting from the upper surface of the concrete structure, the concrete and steel angle stopper that have engaged with the tolerances in the horizontal direction in the placed superstructure upper receiving cavity formed over the structure, and a prestressing member disposed in the concrete structure The concrete structure is provided with a horizontal prestress from the front side surface to the inside of the concrete structure, and the prestress in the direction opposite to the external force received by the steel angle stopper from the superstructure is generated by the prestress applying member. It is given to things.

In the other steel angle stopper embedded portion reinforcing structure, the prestress applying member is further arranged at least in the vicinity of the upper surface of the concrete structure.

In still another steel angle stopper embedded portion reinforcing structure, the prestress applying member is further oriented in the vertical direction, which is the direction in which the steel angle stopper extends, and in a direction orthogonal to the horizontal direction. with respect to the left-right direction it is, are disposed on both sides of at least the steel angle stopper.

In yet another steel angle stopper embedded reinforcement structure, further, when the distance from the steel angle stopper until the front side of the concrete structure is d, the prestressing member, with respect to the previous Kihidari right, at least It is arranged within a range from both side surfaces of the steel angle stopper to a distance d.

In yet another steel angle stopper embedded reinforcement structure, further, the pre-stressing element, with respect to prior Kihidari rightward is disposed within the range of from at least both sides of the steel angle stopper to a distance d / 2 To.

In yet another steel angle stopper embedded portion reinforcing structure, the concrete structure is a rigid frame viaduct or a pier.

In the steel angle stopper embedded reinforcement method, embedded in a concrete structure is a substructure of at least the lower end of the steel angle stopper, at least the upper end of the steel angle stopper protruding from an upper surface of the concrete structure, the concrete structure and Rukoto fitted with a tolerance in the horizontal direction in the placed superstructure upper receiving cavity formed on the, arranged a pre-stressing element to the concrete structure, prior to the concrete structure It is a horizontal prestress from the side surface to the inside, and the prestress in the direction opposite to the external force received by the steel angle stopper from the superstructure is applied to the concrete structure by the prestress applying member. Including.

According to the present disclosure, prestress is applied to a concrete structure in which a steel angle stopper is embedded. As a result, the horizontal stress generated in the concrete structure can be reduced, and the durability of the concrete structure can be improved.

It is a perspective view which shows the example which applied the conventional steel angle stopper to the connecting part between a substructure and a superstructure. It is a photograph showing the damage caused by the earthquake to the substructure in which the conventional steel angle stopper is embedded. It is a schematic side perspective view which shows the connection part of the substructure and superstructure in which the conventional steel angle stopper is embedded. It is a two-sided view explaining the damage of the substructure in which the conventional steel square stopper is embedded. It is a schematic side perspective view explaining the stress acting on the substructure in which the conventional steel angle stopper is embedded. It is a schematic side view which shows the connection part of the substructure and the superstructure in which the steel angle stopper and the prestress applying member are embedded in this embodiment. It is a schematic front perspective view which shows the connection part of the substructure and the superstructure in which the steel angle stopper and the prestress applying member are embedded in this embodiment. It is a schematic plan view which shows the application position of the prestress in this embodiment.

Hereinafter, the present embodiment will be described in detail with reference to the drawings.

FIG. 6 is a schematic side perspective view showing a connecting portion between the substructure and the superstructure in which the steel angle stopper and the prestress applying member are embedded in the present embodiment, and FIG. 7 is the steel angle stopper and the pre-stress in the present embodiment. FIG. 8 is a schematic front perspective view showing a connecting portion between a substructure in which a stress applying member is embedded and a superstructure, and FIG. 8 is a schematic plan view showing a prestress applying position in the present embodiment.

In the figure, reference numeral 22 denotes a girder end of a viaduct girder as a superstructure in the present embodiment, which is made of reinforced concrete. The viaduct girder may be for railways, roads, or for any purpose, but here, for convenience of explanation, railways. It will be described as the one for which the track 25 is laid on the upper surface thereof. Reference numeral 12 denotes a girder seat of a bridge pier as a substructure which is a concrete structure in the present embodiment, and the girder end 22 is placed on a girder seat upper surface 12a as an upper surface of the concrete structure. ..

In the present embodiment, the explanations in the sections of "background technology" and "problems to be solved by the invention" are used to describe the structure, operation, and effect of each part in the connecting portion between the substructure and the superstructure. Therefore, the same reference numerals as those described in the sections of "Background Technology" and "Problems to be Solved by the Invention" are appropriately omitted by assigning the same reference numerals as those shown in FIGS. 1 to 5. To do.

Further, in the present embodiment, the directions of upper, lower, left, right, front, rear, etc., which are used to explain the configuration and operation of each part of the connecting portion between the substructure and the superstructure and other members, are used. The expressions shown are relative rather than absolute, and are appropriate when each part of the connection between the substructure and the superstructure and other members are in the posture shown in the figure, but the posture is If it changes, it should be changed and interpreted according to the change in posture.

As shown in FIG. 6, in the present embodiment, the prestress applying member 35 is arranged in the concrete of the girder seat 12 in which the lower end of the steel angle stopper 31 and its vicinity are embedded, thereby forming the concrete. The horizontal prestress PS as indicated by the arrow is applied. The prestress applying member 35 includes, for example, an elongated linear member 35a such as an anchor bolt and a plate member 35b such as a washer that engages with the head of the linear member 35a such as a bolt head. .. A fixing means that engages with the surrounding concrete like a screw thread is formed at least in the vicinity of the tip of the linear member 35a. Then, the linear member 35a is horizontal from the front surface 12b of the girder seat, which is one of the side surfaces of the concrete structure and located on the front side of the steel angle stopper 31, toward the inside thereof, that is, toward the rear surface 12c of the girder seat. When pushed into the concrete of the girder seat 12, horizontal prestress PS from the front surface 12b of the girder seat as the front side surface toward the inside is applied to the concrete of the girder seat 12 via the plate member 35b.

Considering the balance of the moment M around the lower end of the steel angle stopper 31 as shown in FIG. 6, the closer the position where the prestress PS is applied to the upper surface 12a of the girder seat, the closer to the lower end of the steel angle stopper 31 which is the center of rotation. Since the distance h, which is the length of the rotating arm, becomes longer, the prestress PS effectively resists the inertial force F of the bridge girder 21. Therefore, it is desirable that the position where the prestress applying member 35 is arranged, that is, the position where the prestressing PS is applied in the vertical direction is in the vicinity of the girder seat upper surface 12a.

Further, as shown in FIG. 7, the prestress applying member 35 is arranged on both the left and right sides of the steel angle stopper 31 in the left-right direction, that is, in the lateral direction. That is, prestress PS is applied to the positions on both the left and right sides of the steel angle stopper 31.

More specifically, as shown in FIG. 8, it is desirable that the prestress PS is applied within a range from the left and right side surfaces of the steel angle stopper 31 to a distance d in a plan view. The distance d is the distance from the steel angle stopper 31 to the front surface 12b of the girder seat.

From past experience, the cracks that occur in the concrete on the front side of the steel angle stopper 31, that is, the shear fracture surface 14, are within an angle range of 45 degrees from the front corner of the steel angle stopper 31 as shown in FIG. It is known to concentrate on. That is, the shear fracture surface 14 generated on the front surface of the steel angle stopper 31 occurs within a range from the front surface of the steel angle stopper 31 to the left and right side surfaces of the steel angle stopper 31 on the front surface 12b of the girder seat to a distance d in the horizontal direction. It can be said that there is a high possibility of doing so. Then, in order to surely prevent the occurrence of the shear fracture surface 14, it is required to apply the prestress PS in the shear fracture surface 14 that will be generated. Therefore, in order to surely prevent the occurrence of the shear fracture surface 14, the prestress PS is applied within the range from the left and right side surfaces of the steel angle stopper 31 having a high probability of the occurrence of the shear fracture surface 14 to the distance d. Further, it is more desirable to apply the prestress PS within a range of a distance d / 2 from the left and right side surfaces of the steel angle stopper 31.

Although only the example in which one prestress applying member 35 is arranged on each of the left and right sides of the steel angle stopper 31 has been described here, two or more of them may be arranged as needed. Further, in the vertical direction, only the example in which the prestress applying member 35 is arranged only at one place near the upper surface 12a of the girder seat has been described, but it may be arranged at two or more places if necessary.

As described above, in the steel angle stopper embedded portion reinforcing structure in the present embodiment, the girder seat 12 of the pier 11 and at least the lower end are embedded in the girder seat 12, and at least the upper end protrudes from the girder seat upper surface 12a. 31 and a prestress applying member 35 arranged on the girder seat 12 are provided, and a horizontal prestressing PS from the front surface 12b of the girder seat to the inside is applied to the girder seat 12. As a result, the prestress PS resists the inertial force F, which is an external force received by the portion of the steel angle stopper 31 protruding from the upper surface 12a of the girder seat. Therefore, the stress generated in the concrete of the girder seat 12 by the inertial force F is reduced, and the durability of the concrete is improved.

Further, the prestress applying member 35 is arranged at least in the vicinity of the girder seat upper surface 12a. As a result, the prestress PS is applied to the position where the rotation arm length from the lower end of the steel angle stopper 31 which is the center of rotation is long, so that the inertial force F can be effectively resisted.

Further, the prestress applying member 35 is arranged at least on the left and right sides of the steel angle stopper 31. This makes it possible to prevent the occurrence of shear fracture surfaces 14 on both the left and right sides of the steel angle stopper 31.

Further, assuming that the distance from the steel angle stopper 31 to the front surface 12b of the girder seat is d, the prestress applying member 35 has a range from at least the left and right side surfaces of the steel angle stopper 31 to the distance d in the left-right direction of the steel angle stopper 31. It is arranged inside. As a result, it is possible to reliably prevent the shear fracture surface 14 from being generated on the front surface of the steel angle stopper 31.

Further, the prestress applying member 35 is arranged within a range of at least a distance d / 2 from the left and right side surfaces of the steel angle stopper 31 in the left-right direction of the steel angle stopper 31. As a result, it is possible to more reliably prevent the shear fracture surface 14 from being generated on the front surface of the steel angle stopper 31.

It should be noted that the disclosure herein describes features relating to preferred and exemplary embodiments. Various other embodiments, modifications and modifications within the scope and purpose of the claims attached herein can be naturally conceived by those skilled in the art by reviewing the disclosure of the present specification. is there.

The present disclosure can be applied to a steel square stopper embedded portion reinforcing structure and method.

11 Pier 12 Girder seat 12a Girder seat upper surface 12b Girder seat front surface 31 Steel angle stopper 35 Prestress applying member

Claims (7)

Concrete structures that are substructures and
At least the lower end is embedded in the concrete structure, at least the upper end, the projects from the upper surface of the concrete structure, the placed horizontally superstructure which is formed in the upper housing cavity on the concrete structure and steel angle stopper that are fitted with the tolerance,
It is provided with a prestress applying member arranged in the concrete structure.
The prestress in the horizontal direction from the front side surface to the inside of the concrete structure , which is opposite to the external force received by the steel angle stopper from the superstructure , is applied to the concrete structure by the prestress applying member. Steel angle stopper embedded part reinforcement structure characterized by being given. The steel angle stopper embedded portion reinforcing structure according to claim 1, wherein the prestress applying member is arranged at least in the vicinity of the upper surface of the concrete structure. Said prestressing member, with respect to the vertical direction the steel angle stopper is the direction that extends, and, in the left-right direction which is perpendicular to the horizontal direction, on both sides of at least the steel angle stopper The steel angle stopper embedded portion reinforcing structure according to claim 1 or 2 to be arranged. When the distance from the steel angle stopper until the front side of the concrete structure and d, the pre-stressing element is previously for Kihidari right, in the range from at least both sides of the steel angle stopper to a distance d in The steel square stopper embedded portion reinforcing structure according to claim 3, which is arranged. The pre-stressing element is previously for Kihidari rightward, the steel angle stopper embedded reinforcement structure of claim 4 which is disposed within a range of from at least both sides of the steel angle stopper to a distance d / 2. The steel angle stopper embedded portion reinforcing structure according to any one of claims 1 to 5, wherein the concrete structure is a rigid frame viaduct or a pier. Embedded in a concrete structure is a substructure of at least the lower end of the steel angle stopper, at least the upper end of the steel angle stopper protruding from an upper surface of the concrete structure, to the placed superstructure on the concrete structure and Rukoto fitted with a tolerance in the horizontal direction formed in an upper housing cavity,
A prestress applying member is arranged on the concrete structure, and the prestress is a horizontal direction from the front side surface to the inside of the concrete structure, which is opposite to the external force received by the steel angle stopper from the superstructure. Is applied to the concrete structure by the prestress applying member.
A method for reinforcing a steel corner stopper embedded portion, which comprises.

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