JP4347158B2 - Steel bridge, steel bridge reinforcement method and repair method - Google Patents

Description

  The present invention relates to a steel bridge used for an elevated road or the like. The present invention also relates to a reinforcing method for reinforcing the steel bridge in advance, and a repair method for repairing the crack when the steel bridge is cracked.

  As shown in FIGS. 6 and 7, the general steel bridge supports the floor plate 1, the beam plate 2 and the beam plate 3 that are orthogonal to the lower surface of the floor plate 1, and the beam plate 3 together with the floor plate 1. The box girder 4 is a main component, and these are made of steel. Specifically, the girder 2 has an I-shaped cross section and extends in the longitudinal direction of the floor plate 1 and is generally called a vertical rib or a valve plate. Usually, a plurality of bars are arranged side by side at a predetermined interval over substantially the entire width direction of the floor plate 1, and the upper end of each girder plate 2 and the lower surface of the floor plate 1 are welded.

  On the other hand, the beam plate 3 has an inverted T-shaped cross section and extends in the width direction of the floor plate 1 and is generally called a horizontal rib. The beam plate 3 is formed with a cut 5 at a position corresponding to each girder plate 2, and has a circular scallop 5 a at the lower end which is the tip of the cut 5. And each girder 2 is penetrated in each notch 5, and one side edge of each notch 5 and one side of each girder 2 are welded. Furthermore, the upper end of the beam plate 3 and the lower surface of the floor plate 1 are welded. These beam plates 3 are arranged at predetermined intervals in the longitudinal direction of the floor plate 1.

  Further, the box girder 4 is a box-like frame body assembled by welding and bolt fastening, and extends in the longitudinal direction of the floor board 1 and supports the beam board 3 together with the floor board 1 at two points in the width direction ( (See support points X1 and X2 indicated by filled triangles in FIG. 7). Usually, the beam plate 3 and the floor plate 1 are assembled to the box girder 4 by welding or bolt fastening. The box girder 4 is placed on a stand (not shown) that is erected on the ground and is fixed by bolt fastening.

  Here, the girder plate 2 plays a role of increasing rigidity against the vertical deflection deformation mainly in the longitudinal direction of the floor plate 1, while the beam plate 3 mainly acts on the vertical deflection deformation in the width direction of the floor plate 1. On the other hand, it plays a role of increasing rigidity. Incidentally, the same structure as the beam plate 2 and the beam plate 3 is also applied to the frame constituting the box beam 4 in order to increase the rigidity of the box beam 4 itself (see FIG. 7).

  By the way, in the steel bridge having such a configuration, a passenger car, a truck, a bus, or the like travels on the floor board 1 (actually on asphalt laid on the upper surface). As shown in FIG. 8, a load F of the vehicle weight is repeatedly given to the floor plate 1, and is mainly transmitted to the beam plate 3 through the beam plate 2. In response to this, the beam plate 3 has a state in which the central portion between the supporting points X1 and X2 by the box girder 4 is repeatedly displaced slightly in the vertical direction. Thereby, as shown in FIG. 9, repeated vertical stress (see the solid arrow in FIG. 9) and repeated shear stress (see the white arrow in FIG. 9) are present in the central portion of the beam plate 3. Arise.

  Then, particularly in the vicinity of the lower end A (the portion surrounded by the dotted line in FIG. 9) of the weld joint W with the beam plate 2 located near the center portion of the beam plate 3, the above-described repeated vertical stress is dominant. As shown in FIG. 10, the fatigue crack C (hereinafter simply referred to as “crack”) starts from the scallop 5a as shown in FIG. May occur). The crack C generated here progresses while opening gradually by the action of continuous repeated vertical stress and the action of repeated shear stress.

  When the crack C reaches a certain length, the above-described shear stress acts dominantly, thereby shifting from the opening deformation mode to the in-plane shear deformation mode along the crack C, as shown in FIG. In addition, the crack C progresses rapidly. Such a crack C not only causes a reduction in the rigidity of the beam plate 3, but also causes excessive vibration of the steel bridge itself, which in turn may lead to pavement depression. Measures need to be taken.

  On the other hand, conventionally, when a crack C occurs in the beam plate 3 and is found, the steel bridge is repaired. As a repair method, for example, as shown in FIG. 12A, a circular through hole 6 is first formed at the tip of a crack C in the beam plate 3. Next, as shown in FIG. 12B, a steel attachment plate 110 is applied to the beam plate 3 so as to cover the crack C. The attachment plate 110 is a flat plate having a height that exceeds the length of the notch 5 including the scallop 5a. Then, as shown in FIG. 12 (c), the bolt 7 is attached to the attachment plate 110 with respect to the beam plate 3 at a plurality of locations across the crack C and at locations corresponding to the through holes 6 formed at the tip of the crack C. Fasten with bolts.

  By doing so, the notch coefficient at the tip of the crack C is reduced by the through-hole 6, so that the progress of the crack C can be stopped. At the same time, the beam plate 3 is strengthened by the attachment plate 110 and a part of the repeated vertical stress and the repeated shear stress generated in the beam plate 3 is borne by the attachment plate 110. That vertical stress and shear stress are reduced. As a result, it is possible to suppress further development of the crack C.

  It is also important to reinforce the steel bridge before the crack C occurs in the beam plate 3. The reinforcing method is almost the same as the above repair method, but covers the vicinity of the lower end A of the welded joint portion W of the beam plate 3 with the beam plate 2, that is, the portion where the crack C is supposed to occur. The steel attachment plate 110 is attached to the beam plate 3, and the attachment plate 110 is bolted to the beam plate 3 with bolts 7 at a plurality of points straddling the vicinity of the lower end A of the weld joint portion W in the vertical direction (for example, , See Patent Document 1).

In this way, the repetitive compressive stress and shear stress borne by the beam plate 3 are reduced by the attachment plate 110 in the same manner as the effect of the repair method described above. As a result, it is possible to suppress the generation of cracks C. Even if the crack C occurs, the progress of the crack C is alleviated.
JP 2001-207415 A

  However, in the conventional steel bridge repairing and reinforcing methods described above, although the beam plate 3 is strengthened by the attachment plate 110, the load F of the vehicle weight caused by repeated vertical stress and shear stress on the beam plate 3 is obtained. Is still transmitted directly to the beam plate 3 via the beam plate 2. Therefore, actually, the vertical stress generated in the beam plate 3 is not so much reduced, and the shear stress is not significantly reduced. Therefore, it can be said that the conventional steel bridge repair method and reinforcement method still have problems in terms of certainty regarding the suppression of the occurrence of cracks C in the beam plate 3.

  Then, this invention is made | formed in view of said problem, and it aims at providing the steel bridge which can suppress generation | occurrence | production and progress of a crack in a beam board with high certainty. Another object of the present invention is to provide a method for reinforcing a steel bridge capable of suppressing the occurrence of cracks in a beam plate with high certainty and a method for repairing a steel bridge capable of suppressing the progress of cracks with high certainty.

  In order to achieve the above object, a steel bridge according to the present invention includes a steel floor plate, steel girders perpendicular to the lower surface of the floor plate, and a notch having a circular scallop at the tip while passing through the girder plate. And a box girder that supports the beam plate together with the floor plate, the bottom surface of the floor plate and the upper end of the beam plate are welded and joined, and one side surface of the beam plate and the beam plate In the steel bridge in which one side edge of the notch is welded and the lower surface of the floor plate and the upper end of the beam plate are welded, the notch including the scallop while covering the welded joint portion of the beam plate and the beam plate An attachment plate having an L-shaped cross-section having a height exceeding the length of is attached to the beam plate and the beam plate by bolting.

  As a result, the beam plate is strengthened by the attachment plate, and further, the load of the vehicle weight caused by repeated vertical stress and shear stress on the beam plate is transmitted through the beam plate and the attachment plate in order. . Therefore, both vertical stress and shear stress in the vertical direction generated in the beam plate are remarkably reduced.

  The steel bridge reinforcing method according to the present invention for achieving the above object includes a steel floor plate, a steel beam plate orthogonal to the lower surface of the floor plate, and a circular scallop at the tip while passing through the beam plate. A steel bridge reinforcing method comprising: a beam plate having an incision formed therein; and a box girder that supports the beam plate together with the floor plate, wherein the lower surface of the floor plate and the upper end of the beam plate are welded and joined. For the steel bridge where one side of the plate and one side edge of the notch in the beam plate are welded and the lower surface of the floor plate and the upper end of the beam plate are welded, the lower end of the welded joint between the beam plate and the beam plate The steel bridge reinforcing method for reinforcing the vicinity is characterized by the following points.

  An attachment plate having an L-shaped cross section having a height exceeding the length of the notch including the scallop and covering the welded joint between the beam plate and the beam plate is bolted to the beam plate and the beam plate. To do. As a result, the beam plate is strengthened by the attachment plate, and further, the load of the vehicle weight caused by repeated vertical stress and shear stress on the beam plate is transmitted through the beam plate and the attachment plate in order. . Therefore, both vertical stress and shear stress in the vertical direction generated in the beam plate are remarkably reduced.

  Unlike this, the diameter of the scallop may be increased. As a result, the position where the repeated vertical stress in the vertical direction in the beam plate is concentrated from the part where cracking is supposed to occur, i.e., near the lower end of the welded joint between the beam plate and the beam plate. The vertical stress near the lower end is substantially relieved.

  A steel bridge repair method according to the present invention for achieving the above object includes a steel floor plate, a steel beam plate orthogonal to the lower surface of the floor plate, and a circular scallop at the tip while passing through the beam plate. A steel bridge repair method comprising: a beam plate having a notch formed therein; and a box girder that supports the beam plate together with the floor plate, wherein the lower surface of the floor plate and the upper end of the beam plate are welded and joined. For the steel bridge where one side of the plate and one side edge of the notch in the beam plate are welded and the lower surface of the floor plate and the upper end of the beam plate are welded, the lower end of the welded joint between the beam plate and the beam plate A steel bridge repair method for repairing a crack generated in a beam plate starting from a nearby scallop is characterized by the following points.

  An attachment plate having an L-shaped cross section having a height exceeding the length of the notch including the scallop while covering the crack of the beam plate and the welded joint portion between the beam plate and the beam plate and the beam plate A bolt is fastened to the beam plate. As a result, the beam plate is strengthened by the attachment plate, and further, the load of the vehicle weight caused by repeated compressive stress and shear stress on the beam plate is transmitted through the beam plate and the attachment plate in order. . Therefore, both the vertical stress and the shear stress generated in the beam plate are remarkably reduced.

  In contrast to this, it is preferable to install in the box girder a steel diagonal material that supports a portion of the beam plate that corresponds to a portion vertically below the starting point of the crack in a mountain shape. Or you may install in the said box girder the steel bundle material which supports the part corresponded in the vertically downward direction from the origin of the said crack in the said beam plate. If it does in this way, the displacement to the vertical direction of the beam board which used the support point by a box girder as a fulcrum will be restrained by a slanting material or a bundle material, As a result, the shearing stress which arises in a beam plate will be remarkably reduced.

  According to the steel bridge of the present invention, the vertical stress and shear stress generated in the beam plate are remarkably alleviated by the splicing plate, so that it is possible to suppress the occurrence of cracks in the beam plate with high certainty, Even if it occurs, the progress of the crack can be suppressed with high certainty.

  Further, according to the steel bridge reinforcing method of the present invention, since the vertical stress and shear stress generated in the beam plate are remarkably reduced by the joining plate, the occurrence of cracks in the beam plate can be suppressed with high certainty. However, even if a crack occurs, the progress of the crack can be suppressed with high certainty. Moreover, since the repeated vertical stress is substantially relieved in the vicinity of the lower end of the welded joint portion of the beam plate with the beam plate due to the scallop diameter expansion, the occurrence of cracks in the beam plate can be suppressed with high certainty.

  And according to the repair method of the steel bridge of this invention, since the vertical stress and shearing stress which both generate | occur | produce in a beam board are remarkably reduced by an attachment board, the progress of the crack in a beam board can be suppressed with high certainty. . In addition, since the shear stress generated in the beam plate is remarkably reduced by the diagonal material or the bundle material, the progress of the crack in the beam plate can be suppressed with high certainty.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the steel bridge and the repair method thereof according to the first embodiment of the present invention will be described. FIG. 1 is a perspective view of a steel bridge showing a repair procedure relating to the first embodiment. In the figure, parts having the same names and functions as those in FIGS. 6 to 12 are denoted by the same reference numerals, and redundant description will be omitted as appropriate. The same applies to the second to fifth embodiments described later.

  When a crack C is generated in the beam plate 3 (see FIGS. 10 and 11), the steel bridge is repaired by the following procedure. First, as shown in FIG. 1A, a circular through hole 6 is formed at the tip of a crack C in the beam plate 3. The through-hole 6 plays a role of reducing the notch coefficient at the tip of the crack C and stopping the progress of the crack C.

  Next, as shown in FIG. 1B, the corners formed by the beam plate 2 and the beam plate 3 are attached so as to cover the crack C and the welded joint portion W between the beam plate 2 and the beam plate 3. Attaching the contact plate 10. The splicing plate 10 is made of a bent L-shaped steel and has a height exceeding the length of the cut 5 including the scallop 5a.

  Then, as shown in FIG. 1 (c), the bolt 7 is connected to the beam plate 3 at a plurality of locations over the crack C and at locations corresponding to the through holes 6 formed at the tip of the crack C. Fasten with bolts. Further, the attachment plate 10 is bolted to the beam plate 2 with bolts 8 at a plurality of locations.

  In this way, the girder plate 2 and the beam plate 3 are strengthened by the attachment plate 10, and the load F of the vehicle weight caused by repeated vertical stress and shear stress on the beam plate 3 is reduced by the girder plate 2 and the attachment plate. It is transmitted through the plates 10 in order. At that time, most of the repeated vertical stresses and repeated shear stresses to be transmitted to the beam plate 3 are borne by the joining plate 10, so that both the vertical stress and shear stress borne by the beam plate 3 are remarkably reduced. Become so. Therefore, the progress of the crack C in the beam plate 3 can be suppressed with high certainty.

  Of course, the progress of the crack C is also stopped by the through hole 6. However, since the contribution degree of the through-hole 6 is lower than that of the splicing plate 10 for suppressing the progress of the crack C, the through-hole 6 is not necessarily essential, but the progress of the crack C can be suppressed with higher certainty. In view of the above, it is desirable to form the through hole 6 at the tip of the crack C.

  In addition, there is no particular limitation on the bolt fastening portion between the joining plate 10 and the beam plate 3 as long as it crosses the crack C. However, the lower end vicinity A of the weld joint W is close to the girder plate 2 in the vertical direction. The place to straddle is preferable. This is because the joining plate 10 can sufficiently bear the repeated vertical stress and the repeated shear stress resulting from the progress of the crack C.

  Further, the girder plate 2 may be welded to the attachment plate 10 in addition to the bolt fastening. Similarly, the beam plate 3 may be welded to the attachment plate 10 in addition to the bolt fastening. The girder plate 2 and the beam plate 3 are more firmly fixed to the splicing plate 10, and the repetitive compressive stress in the vertical direction and the repeated shear stress in the horizontal direction are sufficiently borne by the splicing plate 10. Because it can.

  In addition, the joining plate 10 is preferably steel as described above from the viewpoint of cost reduction, but may be other metal or fiber reinforcing material such as CFRP as long as the strength allows. It doesn't matter. When a fiber reinforcing material is applied, the fiber extending direction, that is, the reinforcing direction, is preferably at least the vertical direction or the horizontal direction. This is because strengthening in the vertical direction contributes to durability against repeated vertical stress in the vertical direction, and strengthening in the horizontal direction contributes to durability against repeated shear stress. When the joining plate 10 is a fiber reinforcing material, it is effective in that the weight increase of the entire steel bridge can be reduced.

  Next, a steel bridge and a repair method thereof according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view of a steel bridge according to the second embodiment. The feature of the second embodiment is that it is designed to reduce repeated shear stress generated in the beam plate 3.

  In the second embodiment, as shown in FIG. 2, a pair of steel diagonal members 11 having a mountain shape are installed in the box girder 4. Each diagonal member 11 supports, from the top of each other, the starting point of the crack C in the beam plate 3, that is, the lower end vicinity A of the weld joint W with the girders 2 located in the vicinity of the center portion, and the portion corresponding to the vertically lower part. To do. Incidentally, each diagonal member 11 is made of a plate material having an L-shaped cross section, and each of a protruding piece 3 a called a gusset protruding from the beam plate 3 and a protruding piece 4 a called a gusset protruding from the box girder 4, It is installed by bolting the end.

  In this way, the diagonal member 11 restrains the displacement of the beam plate 3 in the vertical direction about the support points X1 and X2 by the box girder 4 as a fulcrum, and as a result, the shear stress generated in the beam plate 3 becomes remarkable. It will be reduced. Therefore, the progress of the crack C in the beam plate 3 can be suppressed with high certainty.

  Next, a steel bridge and a repair method thereof according to a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view of a steel bridge according to the third embodiment. The feature of the third embodiment is that the repeated shear stress generated in the beam plate 3 is reduced as in the second embodiment.

  In the third embodiment, as shown in FIG. 3, a steel bundle 12 is installed in the box girder 4. The bundle 12 supports in the vertical direction the starting point of the crack C in the beam plate 3, that is, the lower end vicinity A of the welded joint W with the beam plate 2 located in the vicinity of the central portion, and the portion corresponding to the vertically lower side. Incidentally, the bundle member 11 is also made of a plate material having an L-shaped cross section, like the diagonal member 11 in the second embodiment, and a protrusion piece 3 a protruding from the beam plate 3 and a protrusion protruding into the box girder 4. Each end is installed on the piece 4a ′ by bolting.

  In this manner, as in the second embodiment, the bundle member 12 restrains the displacement of the beam plate 3 in the vertical direction about the support points X1 and X2 by the box girder 4 as a fulcrum, and as a result, the beam plate Since the shear stress generated in 3 is significantly reduced, the progress of the crack C in the beam plate 3 can be suppressed with high certainty.

  Then, the steel bridge which is 4th Embodiment of this invention, and its reinforcement method are demonstrated. FIG. 4 is a perspective view of a steel bridge showing a reinforcing procedure related to the fourth embodiment. In addition, although said 1st-3rd embodiment was an aspect which repairs about the crack C when the crack C arises in the beam board 3 which is a component of a steel bridge, on the other hand, this 1 4th Embodiment and 5th Embodiment mentioned later are aspects which reinforce the steel bridge in the step before the crack C arises.

  In the fourth embodiment, the steel bridge is reinforced by the following procedure. First, as shown in FIGS. 4 (a) and 4 (b), the vicinity of the lower end A of the welded joint W with the beam 2 located near the central portion of the beam plate 3, that is, the occurrence of a crack C is assumed. The joint plate 10 is placed on the corner formed by the beam plate 2 and the beam plate 3 so as to cover the portion to be covered. As in the first embodiment, the attachment plate 10 is made of a steel having a bent L-shaped cross section, and has a height exceeding the length of the notch 5 including the scallop 5a. is there.

  Then, as shown in FIG. 4 (c), the attachment plate 10 is fastened to the beam plate 3 with bolts 7 at a plurality of locations straddling the lower end vicinity A of the weld joint portion W in the vertical direction.

  By doing so, the girder plate 2 and the beam plate 3 are strengthened by the attachment plate 10 as in the first embodiment, and the vehicle weight caused by repeated compressive stress and shear stress on the beam plate 3 is increased. The load F is transmitted through the beam plate 2 and the attachment plate 10 in order. At that time, most of the repeated vertical stresses and repeated shear stresses to be transmitted to the beam plate 3 are borne by the joining plate 10, so that both the vertical stress and shear stress borne by the beam plate 3 are remarkably reduced. Become so. Therefore, the generation of the crack C in the beam plate 3 can be suppressed with high certainty, and even if the crack C occurs, the progress of the crack C can be suppressed with high certainty.

In addition, although there is no limitation in particular about the location of the bolt fastening of the joining plate 10 and the beam plate 3, the location which is near the girder plate 2 and straddles the lower end vicinity A of the weld joint W in the vertical direction is preferable.
Repeating compressive stress in the vertical direction due to the occurrence of the crack C can be sufficiently borne by the joining plate 10, and even if the crack C occurs, the repeated vertical stress and the repetition due to the progress of the crack C are repeated. This is because the shearing stress can be sufficiently borne by the joining plate 10.

  Similarly to the first embodiment, the girder plate 2 may be welded to the splicing plate 10 in addition to the bolt fastening, or the beam plate 3 may be welded to the joining plate 10 in addition to the bolt fastening. Good. Furthermore, the joining plate 10 may be another metal or a fiber reinforcing material such as CFRP.

  Next, a steel bridge and a reinforcing method thereof according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view of a main part of a steel bridge according to the fifth embodiment.

  In the fifth embodiment, as shown in FIG. 5, the scallop 5a included in the notch 5 welded to the beam plate 2 located near the central portion of the beam plate 3 is cut to increase the diameter.

  In this way, the position where the repeated compressive stress in the vertical direction in the beam plate 3 is concentrated is the portion where the crack C is supposed to be generated, that is, the welded joint portion W between the beam plate 2 and the beam plate 3 in the first place. It moves to the side portion vicinity B of the scallop 5a that is separated from the lower end vicinity A. That is, the vertical stress in the vicinity A of the lower end is substantially relaxed, and as a result, the generation of the crack C in the beam plate 3 can be suppressed with high certainty.

  In addition, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. Of course, the second embodiment or the third embodiment may be combined with the first embodiment, or the fifth embodiment may be combined with the fourth embodiment.

  The present invention is useful for steel bridges.

It is a perspective view which shows the repair procedure of the steel bridge regarding the steel bridge which is 1st Embodiment of this invention, and its repair method. It is sectional drawing of the steel bridge regarding the steel bridge which is 2nd Embodiment of this invention, and its repair method. It is sectional drawing of the steel bridge regarding the steel bridge which is 3rd Embodiment of this invention, and its repair method. It is a perspective view which shows the reinforcement procedure of the steel bridge regarding the steel bridge which is 4th Embodiment of this invention, and its reinforcement method. It is principal part sectional drawing of the steel bridge regarding the steel bridge which is 5th Embodiment of this invention, and its reinforcement method. It is a perspective view of a steel bridge. It is sectional drawing of a steel bridge. It is a schematic cross section of the steel bridge which shows the load condition of the vehicle weight given to a steel bridge. It is principal part sectional drawing of the steel bridge which shows the generation | occurrence | production state of the compressive stress to the perpendicular direction in the beam board which is a component of a steel bridge, and the shear stress to a horizontal direction. It is principal part sectional drawing of the steel bridge which shows the generation | occurrence | production state of the crack in the beam board which is a component of a steel bridge. It is principal part sectional drawing of the steel bridge which shows the progress condition of the crack in the beam board which is a component of a steel bridge. It is a perspective view which shows the repair procedure of the conventional steel bridge.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Floor board 2 Girder board 3 Beam board 4 Box girder 5 Scallop 6 Through-hole 7, 8 Bolt 10 Attachment board 11 Diagonal material 12 Bundled material

Claims (11)

A steel floor plate, a steel girder plate orthogonal to each other with respect to the lower surface of the floor plate, a beam plate having a circular scallop at the tip while passing through the girder plate, and a box that supports the beam plate together with the floor plate A steel bridge comprising a girder,
A steel bridge where the lower surface of the floor plate and the upper end of the beam plate are welded, one side surface of the beam plate and one side edge of the notch in the beam plate are welded, and the lower surface of the floor plate and the upper end of the beam plate are welded. In
An attachment plate having an L-shaped cross section having a height exceeding the length of the notch including the scallop and covering the welded joint between the beam plate and the beam plate is bolted to the beam plate and the beam plate. A steel bridge characterized by being prepared.   2. The bolt according to claim 1, wherein the attachment plate is bolted to the beam plate at a location that straddles the vicinity of the lower end of the welded joint portion between the beam plate and the beam plate in the vertical direction. Steel bridge.   The steel bridge according to claim 1, wherein the joining plate is made of steel.   The steel bridge according to claim 3, wherein at least one of the beam plate or the beam plate is welded to the attachment plate.   The steel bridge according to claim 1 or 2, wherein the splicing plate is made of a fiber reinforcing material reinforced at least in the vertical direction or the horizontal direction. A steel floor plate, a steel girder plate orthogonal to each other with respect to the lower surface of the floor plate, a beam plate having a circular scallop at the tip while passing through the girder plate, and a box that supports the beam plate together with the floor plate A method for reinforcing a steel bridge comprising a girder,
A steel bridge where the lower surface of the floor plate and the upper end of the beam plate are welded, one side surface of the beam plate and one side edge of the notch in the beam plate are welded, and the lower surface of the floor plate and the upper end of the beam plate are welded. On the other hand, in the steel bridge reinforcement method of reinforcing the vicinity of the lower end of the welded joint between the beam plate and the beam plate,
An attachment plate having an L-shaped cross section having a height exceeding the length of the notch including the scallop and covering the welded joint between the beam plate and the beam plate is bolted to the beam plate and the beam plate. A method for reinforcing a steel bridge, comprising: A steel floor plate, a steel girder plate orthogonal to each other with respect to the lower surface of the floor plate, a beam plate having a circular scallop at the tip while passing through the girder plate, and a box that supports the beam plate together with the floor plate A method for reinforcing a steel bridge comprising a girder,
A steel bridge where the lower surface of the floor plate and the upper end of the beam plate are welded, one side surface of the beam plate and one side edge of the notch in the beam plate are welded, and the lower surface of the floor plate and the upper end of the beam plate are welded. On the other hand, in the steel bridge reinforcement method of reinforcing the vicinity of the lower end of the welded joint between the beam plate and the beam plate,
A method for reinforcing a steel bridge, wherein the diameter of the scallop is increased. A steel floor plate, a steel girder plate orthogonal to each other with respect to the lower surface of the floor plate, a beam plate having a circular scallop at the tip while passing through the girder plate, and a box that supports the beam plate together with the floor plate A method of repairing a steel bridge comprising a girder,
A steel bridge where the lower surface of the floor plate and the upper end of the beam plate are welded, one side surface of the beam plate and one side edge of the notch in the beam plate are welded, and the lower surface of the floor plate and the upper end of the beam plate are welded. On the other hand, in the repair method of the steel bridge that repairs cracks generated in the beam plate starting from the scallop near the lower end of the welded joint between the beam plate and the beam plate,
An attachment plate having an L-shaped cross section having a height exceeding the length of the notch including the scallop while covering the crack of the beam plate and the welded joint portion between the beam plate and the beam plate and the beam plate A method of repairing a steel bridge, wherein a bolt is fastened to the beam plate. A steel floor plate, a steel girder plate orthogonal to each other with respect to the lower surface of the floor plate, a beam plate having a circular scallop at the tip while passing through the girder plate, and a box that supports the beam plate together with the floor plate A method of repairing a steel bridge comprising a girder,
A steel bridge where the lower surface of the floor plate and the upper end of the beam plate are welded, one side surface of the beam plate and one side edge of the notch in the beam plate are welded, and the lower surface of the floor plate and the upper end of the beam plate are welded. On the other hand, in the repair method of the steel bridge that repairs cracks generated in the beam plate starting from the scallop near the lower end of the welded joint between the beam plate and the beam plate,
A method for repairing a steel bridge, characterized in that a steel diagonal member that supports a portion of the beam plate that is vertically downward from the crack starting point is installed in the box girder. A steel floor plate, a steel girder plate orthogonal to each other with respect to the lower surface of the floor plate, a beam plate having a circular scallop at the tip while passing through the girder plate, and a box that supports the beam plate together with the floor plate A method of repairing a steel bridge comprising a girder,
A steel bridge where the lower surface of the floor plate and the upper end of the beam plate are welded, one side surface of the beam plate and one side edge of the notch in the beam plate are welded, and the lower surface of the floor plate and the upper end of the beam plate are welded. On the other hand, in the repair method of the steel bridge that repairs cracks generated in the beam plate starting from the scallop near the lower end of the welded joint between the beam plate and the beam plate,
A method for repairing a steel bridge, comprising: installing a bundle of steel that supports a portion of the beam plate corresponding to a portion vertically below the starting point of the crack in the box girder.   The method for repairing a steel bridge according to claim 8, wherein a circular through hole is formed at a tip of the crack in the beam plate.

Images