JP2010196294A - Repair construction method for i-shaped girder bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a repair construction method for restoring functions of a support and a section around the support irrespective of limits on a space below a horizontal girder. <P>SOLUTION: This I-shaped girder bridge is constituted by connecting girder end edge parts of outer main girders 4, 6 each having a full-web girder end and a middle main girder 5 having a cut-out section 7 at its girder end mutually by end horizontal girders 8a, 8b and supporting the girder end of the middle main girder 5 and the end horizontal girders 8a, 8b on each of girder receiving brackets 9b and 9a, 9c provided protrudedly on faces in the direction of bridge axis of the horizontal girder 3 of a steel bridge pier 1 through the support 10. In this repair construction method for the I-shaped girder bridge, new cut-out sections 17 are provided at the girder ends of each of the outer main girders 4, 6, and then new girder receiving brackets 18 are provided in sections corresponding to the horizontal girder 3. The existing girder receiving brackets 9a, 9c for supporting the horizontal girder at each end and the existing support 10 on their upper side are removed, the girder receiving bracket 9b for supporting the middle main girder is reinforced, and then the girder ends of the middle main girder 5 and the outer main girders 4, 6 each provided with the cut-out sections 7, 17 are supported on the reinforced girder receiving bracket 9b and each of the new girder receiving brackets 18 through a new support. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for repairing an I-girder bridge that replaces a support provided at a portion of a steel pier of an I-girder bridge that supports the load of each main girder and reinforces the periphery of the support.

  One type of steel bridge is a multi-main I-girder bridge. As an example of this type of multi-main I-girder bridge, for example, FIG. There are three main I girder bridges as shown in FIG.

  This is made of a gate-shaped steel made up of a pair of pedestals 2 standing on both sides in the bridge width direction, and cross beams 3 extending in the bridge width direction and integrally attached to the respective pedestals 2 at both ends thereof. A pier 1 is provided.

  Further, three main girders 4, 5 and 6 consisting of I-digits are arranged at a required interval in the bridge width direction, and among the main girders 4, 5 and 6, each main girder at both ends in the bridge width direction. (Below, referred to as the outer main girder) 4 and 6 girder ends are full webs, and the main girder (hereinafter referred to as the middle main girder) 5 in the center of the bridge width direction is notched to the lower side. Part 7 is provided. In the middle main girder 5, both side surfaces of a required part of the girder edge that is away from the upper girder end of the notch 7 and girder ends of the outer main girder 4 and 6 located on both sides thereof The upper inner surface of the required part of the spar edge apart from the required dimension is integrally connected to each other via separate cross beams (hereinafter referred to as end cross beams) 8a and 8b extending in the bridge width direction in parallel with the cross beam 3. As the configuration, the end of the girder provided with the notch 7 of the middle main girder 5 and the position closer to the outer end in the bridge width direction of each of the end cross girders 8a and 8b are connected to the cross beam of the steel pier 1 3 is supported by a support (shoe) 10 on the upper side of the support brackets 9a, 9b, 9c projecting at the lower part of each bridge axial direction surface.

According to the I girder bridge having such a configuration, the main beam 4, 5, 6 can be received within the vertical dimension of the horizontal beam 3 by the horizontal beam 3 of the steel pier 1 so that the horizontal beam 3 The height positions of the upper and lower ends of the main girder can be aligned with the height positions of the upper and lower ends of each of the main girders 4, 5 and 6, and this is an advantageous configuration in the case where the girder is restricted due to construction limits or the like. I can do it. 16 (a), (b), (c) and FIG. 17, for convenience of illustration, the description of the floor slabs provided on the upper side of the cross beam 3 and the main girders 4, 5, 6 of the steel pier 1 is omitted. is there. (The same applies to the following figures.)
By the way, in recent years, in the I girder bridge having the configuration as shown in FIGS. 16A, 16B, and 17, the function of each support 10 is deteriorated and the surroundings of the support are damaged due to aging. It has been pointed out.

  Therefore, a so-called main girder full web construction work has been conventionally performed as a repair method capable of performing functional recovery by replacing each of the bearings 10 and reinforcing the surroundings of the bearings (see, for example, Non-Patent Document 1).

  The main girder full web construction is performed, for example, according to the procedures shown in FIGS. 18 (a) (b) to 20 (a) (b) (c). That is, first, as shown in FIGS. 18A and 18B, the cross beam 3 of the steel pier 1 in the I girder bridge having the same configuration as that shown in FIGS. 16A, 16B and 17 is used. On the lower side, a wide additional horizontal beam 11 extending to the lower position of the girder ends of the main girders 4, 5 and 6 in the bridge axis direction is arranged, and its upper end is integrally attached to the lower end of the horizontal beam 3, Both ends in the bridge width direction of the additional horizontal beam 11 are fixed integrally to the two leg posts 2 respectively. At this time, jack-up cradles 12a, 12b, and 12c are placed in advance at the positions directly below the main girders 4, 5, and 6 on the respective bridge axis direction surfaces of the additional horizontal beams 11, and the corresponding main girders 4 are provided. Alternatively, the required dimensions are projected along 5 or 6, respectively. Note that the jack-up cradle 12b below the middle main girder 5 is a full web at the center side of the span rather than the notch 7 of the middle main girder 5, as shown in FIG. Project to the lower position of the part.

  Next, as shown in FIGS. 19 (a), (b), and (c), the jacks 13 installed on the jack-up cradles 12a, 12b, and 12c of the additional lateral beam 11 are respectively jacked up, By receiving the lower flanges of the main girders 4, 5 and 6 on the upper side of the jack 13, the loads acting on the main girders 4, 5 and 6 are received by the jacks 13 and the jack up receptacles. It is transmitted to and supported by the additional lateral beam 11 via the bases 12a, 12b, and 12c.

  Next, as described above, when the load acting on the main girders 4, 5 and 6 is received by the additional lateral beam 11 via the jacks 13 and the jack-up cradles 12a, 12b and 12c, The girder brackets 9a, 9b, 9c and the upper supports 10 provided on each bridge axial direction surface of the cross beam 3 of the steel pier 1 are loaded with the main girders 4, 5, 6 respectively. In this state, the existing girder brackets 9a, 9b, 9c and the existing supports 10 are removed from the transverse beam 3.

  Thereafter, the lower flange provided around the notch 7 of the middle main girder 5 is cut out, and then the girder receiving the end of the middle main girder 5 as shown in FIG. In the space where the bracket 9b and the support 10 have been removed, the full web reinforcing member 14 having the required shape that can be fitted into the notched portion of the web is bolted to the remaining web of the middle main beam 5. Thus, the end of the middle main beam 5 is made full web. Further, the stiffeners 15 on the fulcrum are connected to both side surfaces of the web at the position of the full web-formed middle main girder 5 above the additional lateral beam 11 and above the new support 16 described later. Reinforce by attaching ribs to the lower flange. Similarly, as shown in FIG. 20 (c), at the positions of the outer main girders 4 and 6 above the additional lateral beam 11 and above the new support 16 described later, The fulcrum upper stiffener 15 is reinforced by attaching it to both sides of the web and the lower flange in a rib shape.

  After completing the full web at the end of the middle main beam 5 as described above, as shown in FIGS. 20 (a), (b), and (c), the main beams 4, 5, After the new bearings 16 are installed at positions below the end of the six girders, the jacks 13 are jacked down so that the main girders 4, 5, 6 are connected to the new girders. The support is replaced and the reinforcement work around the support is completed by supporting the additional lateral beam 11 via 16.

  Thereafter, the jacks 13 and the jack-up cradles 12a, 12b, 12c are removed. Further, if necessary, after the middle main girder 5 is fully webbed and before the jacks 13 are jacked down, the existing end cross beams 8a and 8b are moved or replaced. It is.

Tetsuhiro Shimozato, “Operation Rejuvenation of Metropolitan Expressway”, JSSC Journal, Japan Steel Structure Association, October 2003, No. 50, p. 1-10

  However, in the conventional main girder full web construction, the end of each outer main girder 4 and 6 that was originally a full web and the girder end of the middle main girder 5 to be newly fully webbed are newly installed 16. Since it is necessary to provide the additional horizontal beam 11 to be received from below under the existing horizontal beam 3 of the steel pier 1, the space below the existing horizontal beam 3 is limited due to the construction limit, The actual situation is that it cannot be applied to an I-girder bridge in which a vertical space for mounting the additional horizontal beam 11 cannot be secured.

  Therefore, the present invention is provided with an outer main girder having a full web at the end of the girder and a middle main girder having a notch at the end of the girder, and projecting at a required portion of the bridge axial direction surface of the cross beam of the steel pier. On the girder bracket, the upper girder end of the middle main girder notch and the end of the horizontal girder that connects the middle main girder and the girder edges of each outer main girder are located near the outer edge in the bridge width direction. For the I-girder bridge of the type that is configured to be supported by the support, the space for attaching the reinforcing member to the lower side of the transverse beam of the steel pier is limited, and the conventional main girder full web Even if it is not possible to secure the vertical space required to install the additional horizontal beams to be added in the construction work, the repair method for the I-girder bridge that can be used to replace each support and reinforce the support around the support Is to provide.

  In order to solve the above-mentioned problem, the present invention corresponds to claim 1, wherein the outer ends of the outer main girders located at both ends of the bridge width direction are full webs, and the inner ends of the outer width of the bridge are located inside the bridge width direction. The notch of the above-mentioned middle main girder is provided on each girder bracket that has a notch in the lower part of the girder end of the main girder and protrudes at the required position in the bridge width direction on the bridge axial direction surface of the steel beam. The end of the spar and the portion near the outer end of the bridge width direction of each end cross girder that connects the end edges of the middle main girder adjacent to each outer main girder are supported through respective supports. In the I-girder bridge, a notch is newly formed at the end of each outer main girder, and then each outer main girder is located at a position corresponding to each outer main girder on the bridge axial direction surface of the horizontal beam. A new girder bracket that protrudes to the inside of the notch provided at the end of the girder is provided. With each jack installed on each jack-up cradle to protrude, with the main girder jacked up, the existing girder bracket for supporting each end girder and the existing support above it At the same time, the existing support on the upper side of the support bracket for supporting the middle main girder is removed, and then the support bracket for supporting the middle main girder and a new support on the upper side of each of the above new girder brackets. After each of the jacks is jacked down, the ends of the girders in which the notches of the outer main girders are newly installed are placed on the new girder brackets and the middle main girder girders. The ends are supported by the support brackets for supporting the middle main girder via the new bearings.

  In the above configuration, when a notch is newly provided at the end of each outer main girder, it corresponds to a notch to be provided in the outer main girder on both side surfaces of the end of each outer main girder in advance. After attaching the reinforcing material provided with the notches, respectively, the spar ends of the main girders are cut along the notches of the reinforcing materials to form the notches at the spar ends of the main girders. Like that.

  Furthermore, in each of the above-described configurations, after attaching reinforcing members each having a notch portion that is slightly larger than the existing notch portion at both ends of the middle end of the middle main beam, By cutting the web around the existing notch portion of the middle main girder along the notch portion of each reinforcing material, the notch portion reinforced by the reinforcing material at the end of the middle main girder , And the end of the middle main girder provided with the notch reinforced by the reinforcing members is supported on the girder bracket for supporting the middle main girder via a new support.

According to the repair method of the I girder bridge of the present invention, the following excellent effects are exhibited.
(1) Steel piers with notches at the bottom of the girder end of the middle main girder located inside the bridge width direction with full webs at the ends of each outer main girder located at both ends of the bridge width direction In the beam receiving bracket projecting at the required position in the bridge width direction on the bridge axial direction surface of the cross beam, the end of the beam provided with the notch portion of the middle main beam and the middle main beam adjacent to the outer main beam Cut the girder ends of each outer main girder in the I-girder bridge, which supports each side girder connecting the girder edge edges of each girder in the bridge width direction outside end portion by supporting each. A new notch that protrudes to the inside of the notch provided at the end of each outer main girder at the location corresponding to each outer main girder in the bridge axial direction surface of the above-mentioned transverse beam is newly established. A bracket is provided, and each jack installed on each jack-up pedestal that protrudes from a required position on the bridge axis direction surface of the cross beam. Remove the existing girder bracket for supporting each side cross girder and the existing support above it while jacking up each main girder using a stick, and the girder bracket for supporting the middle main girder After removing the existing support on the upper side of each of the above, and then arranging a new support on the support bracket for supporting the middle main girder and each of the new girder brackets, the jacks are jacked. By turning down, the end of the above-mentioned outer main girder is newly installed at the end of each new girder bracket, and the end of the middle main girder is supported by the above-mentioned girder support bracket for the middle main girder. In addition, since each is supported by the new support, the existing support in the I-girder bridge of the above type can be replaced with a new support, and the support point can be removed from the end cross beam. It can be changed to the end of the main digit It is possible to achieve the functional recovery of around bearing and bearing. Furthermore, if the girder bracket for supporting the middle main girder is reinforced, further functional recovery around the bearing can be achieved.
(2) In addition, each outer main girder is a new girder holder that has a new girder with a notch part corresponding to the notch part of each main girder in the direction of the bridge axis of the transverse beam of the steel pier. Since the bracket is placed and supported via a support, even if a large space cannot be secured in the space below the cross beam of the steel bridge pier due to construction limitations, etc. Surrounding reinforcement can be implemented.
(3) When a notch is newly provided at the end of each outer main girder, a notch corresponding to the notch to be provided in the outer main girder on both side surfaces of the end of each outer main girder in advance Are attached, and then the spar ends of the main girders are cut along the notches of the reinforcing members to form notches at the spar ends of the main girders. As a result, it is possible to prevent the possibility that the rigidity in the vicinity of the end of each outer main girder temporarily decreases. Therefore, under the service of the I-girder bridge, it is possible to carry out construction for replacement of the above-mentioned bearings and reinforcement around the bearings.
(4) After attaching reinforcing members each having a notch portion that is slightly larger than the existing notch portion at both ends of the middle main girder end of the middle main beam, Cutting the web around the existing notch of the middle main girder along the notch of the middle main girder to provide a notch reinforced by the reinforcing members at the end of the middle main girder, By supporting the end of the middle main girder, which is provided with a notch reinforced by each reinforcing material, to the girder bracket for supporting the middle main girder via a new support, Even if damage due to fatigue occurs around the existing notch at the beam end, the damaged portion can be removed to reinforce the beam end of the middle main beam.

The procedure of one embodiment of the I girder bridge renovation method of the present invention is shown. (A) is provided with a notch portion at the end of the outer main girder, and a new girder bracket and a temporary jack-up bracket on the horizontal beam. The plan view which shows the state which provided the stand and the cradle for jackup, (b) is an AA direction arrow view of (A), (C) is an BB direction arrow view of (I). . In the repairing method of the present invention, each outrigger and the existing one end cross girder are jacked up, (A) is a schematic plan view, (B) is a CC direction arrow view of (A). FIG. FIG. 3 shows the procedure after jack-up in FIG. 2 in the repair method of the present invention, where (a) shows the state where the existing girder brackets and supports on both sides in the bridge width direction are removed, and (b) shows the other side of the existing one. FIG. 3C is a view corresponding to FIG. 2B showing a state in which the end cross beam is removed, and FIG. FIG. 3 shows the procedure after FIG. 3 (c) in the repair method of the present invention. (A) In place of the existing one end cross beam, a state where a new other end cross beam is jacked up is ) Is a view corresponding to FIG. 2 (b) showing a state in which the jack that has received one end cross beam is removed. Fig. 4 shows the procedure after Fig. 4 (b) in the repair method of the present invention, where (a) shows the state where one of the existing end cross beams has been removed, and (b) shows a new one end cross beam attached. FIG. 3 is a diagram corresponding to FIG. It is a general | schematic cutting side view which shows the state which reinforced the girder bracket of the bridge width direction center part by the repair construction method of this invention. In the renovation method of the present invention, each outrigger and a new other end cross girder are jacked down after a new support is provided. (A) is a schematic plan view, (b) is (b) It is a DD direction arrow line view. The state of removing the temporary jack-up cradle, the jack, the outrigger, and the temporary cross beam and finishing the repair method of the present invention is shown. (A) is a schematic plan view, (B) is E- of (A). E direction arrow view, (c) is the FF direction arrow view of (a). In the repairing method of the present invention, the reinforcing procedure when the outer main girder is provided with a notch is shown. (A) shows a state in which the outer main girder outer reinforcing member is attached to the outer side surface of the outer main girder in the bridge width direction. (B) is a schematic perspective view showing a state where the existing stiffeners on the inner side surface in the bridge width direction of the outer main girder are removed. FIG. 9 shows the procedure after FIG. 9 (b) in the reinforcing procedure when the outer main girder is provided with a notch in the repair method of the present invention. (B) is a schematic perspective view showing a state in which a notch is provided at the end of the outer main girder. FIG. 10 shows the procedure after FIG. 10 (b) in the reinforcing procedure when the outer main girder is provided with a notch in the repairing method of the present invention, and the outer main girder inner girder edge reinforcing material is attached to each outer main girder. It is a schematic perspective view which shows the state to each attach. In the repair method of the present invention, the reinforcement procedure of the end of the middle main girder is shown. (A) shows the state where the existing stiffener on one side of the bridge width direction of the middle main girder is removed. It is a schematic perspective view which shows the state which attached the middle main girder reinforcement to the one side surface of the bridge width direction of the middle main girder, respectively. 12 shows the procedure after FIG. 12 (b) in the reinforcing procedure of the end of the middle main girder in the repair method of the present invention, where (b) shows the existing stiffener on the other end face in the bridge width direction of the middle main girder. (B) is a schematic perspective view showing a state in which the middle main girder reinforcing material is attached to the other side surface in the bridge width direction of the middle main girder. FIG. 13B shows a procedure after FIG. 13B in the reinforcing procedure of the middle main girder end in the repair method of the present invention, and the middle main girder end reinforcing material is provided on each side surface in the bridge width direction of the middle main girder. It is a schematic perspective view which shows the state which attaches each. 14 shows the procedure after FIG. 14 in the reinforcing procedure of the middle main girder end in the repairing method of the present invention, in which the web around the existing notch portion of the middle main girder end is cut and newly It is a schematic side view which shows the state which formed the notch part. It shows the outline of an example of the 3 main I girder bridges that have been used on the Metropolitan Expressway. (B) is a plan view, (b) is a view taken in the direction of arrows GG in (b), (c) (A) is a HH direction arrow directional view. It is a perspective view which expands and shows the support structure part of the main girder in 3 main I girder bridges of FIG. This figure shows the state where an additional horizontal beam is installed under the horizontal beam of the steel pier in the conventional main girder full web construction. (A) is a schematic plan view, (b) is the I- It is an I direction arrow directional view. It shows the state where each main girder is jacked up in the main girder full web construction. (B) is a schematic plan view, (b) is a view taken along arrow JJ in (b), (c) is ( It is a KK direction arrow line view of a). This figure shows the state where each main girder is placed on the upper side of the new bearing after the main main girder is converted into a full web in the main girder full web construction. (B) is a schematic plan view, (b) is (b) ) Is an LL direction arrow view, and (C) is an MM direction arrow view of (A).

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIGS. 1 (a), (b), (c) to FIG. 15 show an embodiment of the repair method for an I-girder bridge according to the present invention, which is as follows.

  That is, as shown in FIGS. 16 (a), (b), and (c) and FIG. 17, the outer main girders 4 and 6 having full webs at the ends of the girders, and the middle main girders 5 having notches 7 at the end of the girders, The beam support brackets 9a, 9b, and 9c projecting on the bridge axial direction surface of the cross beam 3 of the steel pier 1 are connected to the upper spar end of the notch portion 7 of the middle main girder 5 and the middle The portions closer to the outer end in the bridge width direction of the end cross beams 8a and 8b connecting the end portions of the main beam 5 and the outer main beams 4 and 6 are supported via the support 10, respectively. As shown in FIGS. 1 (a) and 1 (b), notches 17 are respectively provided at the lower portions of the girder ends of the outer main girders 4 and 6 in the I-girder bridge.

  Next, the notch portion 17 provided in each outer main girder 4, 6 is located at a lower position corresponding to each outer main girder 4, 6 on each bridge axial direction surface of the cross beam 3 of the steel pier 1. New girder brackets 18 projecting in the direction of the bridge axis inside are provided.

  Further, as shown in FIGS. 1 (a) and 1 (c), a temporary installation is provided at a position corresponding to a portion closer to the inner end portion in the bridge width direction of each of the end cross girders 8a and 8b on each bridge axial direction surface of the cross beam 3. Jack-up cradles 19a and 19b are provided so as to project to positions below the end cross beams 8a and 8b.

  Further, as indicated by the two-dot chain line in FIGS. 1 (a) and 1 (b), in the vicinity of the cross beam 3 on the outer surface of the outer main girders 4 and 6 in the bridge width direction at a position away from the end of the girders. Temporary outriggers 20 that extend up to are respectively provided. On the other hand, a jack-up cradle 21 that protrudes to a position below each of the outriggers 20 is provided at a lower position near the both ends in the bridge width direction corresponding to each of the outriggers 20 on each bridge axial direction surface of the cross beam 3. For example, the new girder bracket 18 is provided as an integral part.

  Furthermore, as shown by the two-dot chain line in FIGS. 1 (a) and 1 (c), the inner side surface in the bridge width direction at a position away from the beam ends of the outer main girders 4 and 6 and the middle main girder. Temporary cross beams 22 extending in the bridge width direction are disposed between both sides of the bridge width direction at the required distance from the end of the five girder ends, and both ends of the temporary cross beams 22 are connected to the outer sides. The main girder 4 and 6 are respectively attached to the inner side surface in the bridge width direction and the both side surfaces of the middle main girder 5 in the bridge width direction.

  Thereafter, as shown in FIGS. 2A and 2B, each jack-up cradle 21 located below each outrigger 20 and a temporary jack-up cradle provided below the one end cross beam 8a. The jacks 23a, 23b, and 23c are respectively installed on the 19a, and the main girders 4, 4a, 23b, and 23c are passed through the outriggers 20 and the one end cross beam 8a above the jacks 23a, 23b, and 23c, respectively. Jack up 5 and 6. As a result, the loads of the main girders 4, 5, 6 applied to the support 10 on the existing girder receiving brackets 9a, 9b, 9c can be received by the jacks 23a, 23b, 23c. Therefore, in this state, as shown in FIG. 3 (a), the girder brackets 9a and 9c on both sides of the bridge width direction and the upper supports 10 are removed. Furthermore, the jack-up operation of the jacks 23a, 23b, and 23c causes the existing other end cross beam 8b to be out of the load transmission path that transmits the load of the main beams 4, 5, and 6 to the cross beam 3. As shown in FIG. 3 (b), the existing other end cross beam 8b in a state where the loads of the main beams 4, 5, 6 are not applied is arranged at both ends in the longitudinal direction with the outer main beam 6 in the middle. After removing the main girder 5 from the main girder 5 and then reinforcing the outer main girder 6 and the middle main girder 5 in the removed portion of the existing other end cross girder 8b as described later, FIG. As shown in FIG. 4, a new other end cross beam 24b extending in the bridge width direction is provided between the reinforced beam end edges on the upper side of the notches 17 and 7 of the outer main beam 6 and the middle main beam 5. Are attached together.

  After the existing other end cross beam 8b is replaced with a new other end cross beam 24b as described above, as shown in FIG. 4 (a), below the new other end cross beam 24b. By installing another jack 23d on the temporary jack-up cradle 19b located at the position and jacking up the new other end cross beam 24b with the jack 23d, the main girders 4, 5, 6 can be received by the jack 23d that receives the new other end cross beam 24b and the jacks 23a and 23b that receive the outriggers 20 described above. As a result, the jack 23c that has received the one end cross girder 8a can be jacked down, and the jack 23c is jacked down and removed as shown in FIG.

  When the jack 23c that has received the existing one end cross beam 8a is jacked down, the existing one end cross beam 8a transmits the load of the main girders 4, 5, 6 to the cross beam 3. As shown in FIG. 5 (a), both ends in the longitudinal direction of the existing one side beam 8a in a state where the loads of the main beams 4, 5, and 6 no longer act are removed from the path. After the main girder 4 and the middle main girder 5 are separated and removed, the outer main girder 4 and the middle main girder 5 are reinforced as described later, as shown in FIG. A new one end cross beam 24a extending in the bridge width direction is integrally attached between the upper edge portions of the notches 17 and 7 of the beam 4 and the middle main beam 5.

  Further, in the state where the loads of the main girders 4, 5 and 6 are received by the jacks 23a, 23b and 23d, as shown in FIG. 6, the jacks are installed on the upper side of the girder bracket 9b in the center of the bridge width direction. The existing support 10 is removed, and a series of lower beam flange brackets 9b provided on both sides in the bridge axis direction of the horizontal beam 3 is passed through the lower side of the lower flange of the horizontal beam 3. And the upper end of the beam bracket reinforcing member 25 is integrally attached to the lower side of each beam bracket 9b at the center in the bridge width direction and the lower flange of the cross beam 3. Thus, each girder bracket 9b is reinforced.

  Thereafter, as shown in FIGS. 7 (a) and 7 (b), the upper side of the reinforced girder bracket 9b in the center of the bridge width direction of the bridge beam direction surface of the cross beam 3 of the steel pier 1 and the both ends in the bridge width direction. After providing a new support 26 on the upper side of each of the new girder brackets 18, the jacks 23 a, 23 b, 23 d receiving the outriggers 20 and the new other end horizontal girder 24 b are both jacked down. Thus, on the upper side of each support 26, the upper end of the notch 7 of the middle main girder 5 and the upper girder of the notch 17 newly provided on each of the outer main girders 4 and 6 are provided. The ends are respectively placed, and the loads of the middle main girder 5 and the outer main girders 4 and 6 are applied to the new bearings 26, the reinforced girder bracket 9b at the center in the bridge width direction, and both ends in the bridge width direction. The steel bridge via each new girder bracket 18 on the side So as to subject tell 1 of the cross beams 3.

  After the loads of the main girders 4, 5 and 6 are supported on the cross beam 3 through the new bearings 26 and the girder brackets 9b and the new girder brackets 18 as described above, The temporary jackup cradle 19a, 19b, each outrigger 20 and each temporary horizontal girder 22 are removed to complete the repair work for the I-girder bridge. As a result, as shown in FIGS. 8 (a), (b), and (c), the end of the girder provided with the notch 17 of each of the outer main girders 4 and 6 is provided below the bridge axial direction surface of the transverse beam. The upper ends of the new girder brackets 18 provided at the locations are respectively supported via new supports 26, and the end of the girder provided with the notch portion 7 of the middle main girder 5 is provided at the center of the reinforced bridge width direction. I having a structure in which the existing brackets 9a and 9c supporting the outer main girders 4 and 6 are removed from the upper side of the girder bracket 9b via a new support 26. Try to construct a girder bridge renovation structure.

  In the above, when the notch portion 17 is newly provided at the end of the girder that is the full web of each of the outer main girders 4, 6, the girder height suddenly changing portion formed by providing the notch portion 17, In order to ensure the rigidity that can withstand the load applied to the outer main girders 4 and 6, the vicinity of the end portions of the outer main girders 4 and 6 around the newly formed notch 17 is reinforced. There is a need to. In view of this point, the present invention reinforces the periphery of the notch 17 provided in each of the outer main girders 4 and 6 according to the procedure shown in FIGS. .

  That is, first, as shown in FIG. 9 (a), notches corresponding to the shape of the notches 17 to be formed are formed on the outer surface in the bridge width direction near the end portions of the outer main girders 4 and 6. An outer main girder outer reinforcing member 27 having a portion 17a and having a lower flange 28a along the cutout portion 17a is integrally attached.

  Next, as shown in FIG. 9 (b), in the region on the side farther from the end of the girder than the end lateral girders 8a and 8b in the vicinity of the end of the girder on the inner side surface in the bridge width direction of the outer main girders 4 and 6. After the attached rib-shaped existing stiffener 29 is cut and removed, and the cut surface of the existing stiffener 29 is flattened by a grinder or the like, as shown in FIG. In the region where the existing stiffeners 29 on the side farther from the end of the girders than the side girders 8a and 8b in the vicinity of the girders on the inner side surface of the girders 4 and 6 are removed, the outer main girders 4 , 6 having a notch 17b corresponding to the shape of the notch 17 to be formed at the end of the spar and having the lower flange 28b along the notch 17b. To be attached to.

  Next, as shown in FIG. 10 (b), the lower main web is placed at the lower end of the web at the end of each outer main girder 4, 6 (only the outer main girder 6 is shown in FIG. 10 (b)). Cut along the shape of the notches 17a and 17b of the outer reinforcing member 27 and the inner reinforcing member 30 for 4 and 6, so as to form the notch 17 at the ends of the outer main girders 4 and 6. It is.

  Thereafter, as shown in FIG. 11, when the other end cross beam 8b (see FIG. 3) attached to the inner side surface in the bridge width direction of the outer main beam 6 is removed as shown in FIG. An outer side provided with a lower flange 28c along the upper side of the newly formed notch 17 in the region from the removed part of the other end cross beam 8b to the end of the beam on the inner side surface in the bridge width direction of the outer main beam 6. The edge part opposite to the side where the main girder inner girder end reinforcing material 31 is arranged closer to the outer main girder end girder end reinforcing member 31 in the outer main girder inner girder end reinforcing material 31 is The outer main girder 6 is integrally attached via the filler plate 32 in a state where it is arranged with the required dimensions overlapped on the end edge portion on the side arranged near the girder end. Although not shown, the outer main girder 4 is also attached to the inner side surface in the bridge width direction of the outer main girder 4 as shown in FIG. When the one end cross beam 8a is removed, the newly formed notch is formed in a region from the removed portion of the one end cross beam 8a to the end of the girder on the inner surface of the outer main beam 4 in the bridge width direction. An outer main girder inner girder end reinforcement 31 having a lower flange 28 c along the upper side of 17 is integrally attached via a filler plate 32. As a result, the notch portions 17 are provided at the ends of the outer main girders 4 and 6, respectively, and the girder height suddenly changing portions formed by the notch portions 17 are attached to both side surfaces in the bridge width direction. Each reinforcing material 27, 30, 31 can be reinforced strongly.

  Further, in the present invention, in order to be able to reinforce the periphery of the bearing even in the case where damage due to fatigue has occurred around the existing notch portion 7 of the middle main girder 5, FIG. B) Through the procedure shown in FIG. 15, the end of the middle main beam 5 is also reinforced.

  Specifically, as shown in FIG. 12 (a), first, the side of the middle main girder 5 on the side farther from the girder than the one side girder 8a in the vicinity of the girder end of one side surface in the bridge width direction. After the rib-shaped existing stiffener 33a attached to the region is cut and removed, and the cut surface of the existing stiffener 33a is flattened by a grinder or the like, as shown in FIG. In the region of the side of the main girder 5 near the side of the girder on one side in the width direction of the bridge, in the region on the side farther from the girder end than the one side girder 8a, it is slightly more than the existing notch 7 of the middle main girder 5 A first middle main girder reinforcing member 34a having a large notch 35a and having a lower flange 36a around the notch 35a is integrally attached.

  Further, in the same manner as above, the region on the side farther from the beam end than the other side beam 8b in the vicinity of the beam end of the other side surface of the middle main beam 5 in the bridge width direction is also shown in FIG. As shown in FIG. 13, after the rib-shaped existing stiffener 33b is cut and removed and the cut surface of the existing stiffener 33b is flattened by a grinder or the like, the middle main girder 5 as shown in FIG. A notch that is slightly larger than the existing notch portion 7 of the middle main girder 5 in a region farther from the girder end than the other end cross girder 8b in the vicinity of the girder end portion on the other side surface of the bridge width direction. A second middle main girder reinforcing member 34b having a portion 35b and having a lower flange 36b around the notch 35b is integrally attached.

  Next, as shown in FIGS. 3 (b) and 5 (a), when the end cross beams 8b and 8a attached to the both sides of the middle main beam 5 are sequentially removed, 14, the lower flange 36a of each of the middle main girder reinforcing members 34a, 34b is provided in a region from the removed portion of each of the end cross girders 8b and 8a to the end of the girder on both sides in the bridge width direction of the middle main girder 5. , 36b and lower flanges 36c, 36d respectively corresponding to the middle main girder end reinforcing members 37a, 37b are arranged near the end of the middle main girder 5 in the middle main girder end reinforcing members 37a, 37b. In a state where the end edge on the side opposite to the side is arranged to overlap the required dimension on the end edge on the side of the middle main girder reinforcing member 34a, 34b, which is located near the end of the middle main girder 5, The plates 38 are sequentially attached integrally with the plate 38 interposed therebetween.

  Thereafter, as shown in FIG. 15, the lower flanges 36a and 36b around the notches 35a and 35b of the middle main girder reinforcement members 34a and 34b, and the middle main girder edge reinforcement members 37a and 37b, respectively. At a position along the flanges 36c and 36d, the web around the existing notch 7 below the end of the middle main girder 5 is cut, and the middle main girder 5 is used for the middle main girder 5 A new notch 7a whose periphery is strongly reinforced by the reinforcing members 34a and 34b and the girder end reinforcing members 37a and 37b can be formed. If a new notch 7a that is slightly larger than the existing notch 7 is formed at the end of the middle main girder 5 as described above, the girder height at the end of the middle main girder 5 is initially changed. It is smaller than the digit height. Therefore, the decrease in the girder height is set by setting the thickness dimension of the new support 26 that receives the upper girder end of the newly formed notch 7a to be thicker than the original thickness dimension, or by a sole (not shown). It is assumed that the height position of the upper end of the middle main beam 5 is not changed by increasing the thickness dimension of the plate.

  As described above, the existing lateral girders 8b and 8a are provided on the inner side surfaces of the outer main girders 4 and 6 in the bridge width direction and on both side surfaces of the middle main girder 5 in the bridge width direction. Since the girder end reinforcements 31 and 37a, 37b are integrally attached to the removed portions of the end cross beams 8b and 8a, respectively, the existing end cross beams 8b and When the new end cross beams 24a and 24b are provided as shown in FIGS. 3 (c) and 5 (b) after the removal of 8a, both ends of the new end cross beams 24a and 24b are Each girder end reinforcement 31 is attached to each of 37a and 37b.

  When a new girder bracket 18 integrated with each jack-up pedestal 21 is provided on each bridge axial direction surface of the cross beam 3 of the steel pier 1, each bridge of the cross beam 3 as shown in FIG. A new girder bracket 18 integrated with each of the jack-up cradles 21 is disposed at a predetermined lower portion of the axial surface so that the lower end of the new girder bracket 18 protrudes below the horizontal beam 3 to the required dimension. A connecting member 39 extending in the bridge axis direction through the lower side of the horizontal beam 3 is arranged between the members corresponding to the bridge axis direction across the horizontal beam 3 at the lower end protruding portion of the new girder bracket 18, Both end portions in the longitudinal direction of the member 39 are integrally attached to the lower end protruding portions of the respective new beam receiving brackets 18, and the upper end portion of the connecting member 39 is integrally attached to the lower side of the lower flange of the transverse beam 3. A. Further, a transverse beam extending in the direction of the bridge axis in the transverse beam 3 between the required portions on the inner surface of the web of the transverse beam 3 which is inside the attachment location of each of the new girder brackets 18 in each bridge axis direction surface of the transverse beam 3. The internal reinforcing member 40 is disposed, and both longitudinal ends thereof are integrally attached to required portions of the inner surface of the web of the cross beam 3, and the lower end portion of the cross beam internal reinforcing member 40 is connected to the upper side of the lower flange of the horizontal beam 3. By attaching them integrally to each other, it is possible to reinforce the installation location of each of the new girder brackets 18 in the horizontal beam 3 around the bearing.

  Thus, according to the repair method of the I girder bridge of the present invention, the girder ends are provided with the outer main girders 4 and 6 having full webs, and the middle main girder 5 having the notch portions 7 at the girder ends. Girder brackets 9b, 9a and 9c projecting from the bridge axial direction surface of the cross beam 3 of the bridge pier 1 are connected to the upper end of the notch 7 of the middle main girder 5, the middle main girder 5 and the outside Existing support in an I-girder bridge of a certain type that supports the laterally outer portions of the end cross beams 8a and 8b connecting the end edges of the main girders 4 and 6 via the support 10 respectively. 10 can be exchanged for a new bearing 26, and the function can be restored.

  Each of the outer main girders 4 and 6 is provided with a notch portion 17, and the upper end of the notch portion 17 is placed at a lower portion of the bridge axial direction surface of the cross beam 3 of the steel pier 1. Since the new girder bracket 18 protruded is placed via the support 26, it is necessary to add to the space below the cross beam 3 of the steel bridge pier 1 by the conventional main girder full web construction work. Even when a space for providing a certain additional horizontal beam cannot be secured due to a construction limit or the like, the existing bearings 10 can be replaced with new bearings 26 and reinforcement around the bearings can be performed.

  In addition, the outer main girders 4 and 6 are formed on the outer side surface in the bridge width direction near the end portions of the outer main girders 4 and 6 before the existing stiffener 29 on the inner side surface in the bridge width direction is removed. Since the outer main girder outer reinforcing member 27 is integrally attached to reinforce, it is possible to prevent the possibility that the rigidity in the vicinity of the girder ends of the outer main girders 4 and 6 temporarily decreases. For the middle main girder 5 as well, after the existing stiffener 33a on one side in the bridge width direction is removed, the middle main girder reinforcing member 34a is integrally attached to one side in the bridge width direction, and then the other in the bridge width direction and the like. Since the existing stiffener 33b on the side surface is removed, it is possible to prevent a possibility that the rigidity in the vicinity of the end of the middle main girder 5 temporarily decreases. Therefore, in the state where the road on the floor slab (not shown) provided above the horizontal beam 3 and the main girders 4, 5, 6 is used, the existing bearings 10 are replaced with new bearings 26, It becomes possible to carry out reinforcement work around the bearing.

  In addition, this invention is not limited only to the said embodiment, In each said embodiment, each jack 23a used in order to jack up so that a load may not act sequentially on the existing end cross beam 8a, 8b. , 23b, 23c, and 23d, the jacks 23a and 23b are installed above the jack-up cradles 21 projecting from predetermined positions on the respective bridge axial directions of the cross beams 3 of the steel pier 1 and Although the outrigger 20 temporarily installed on the outer side surface in the bridge width direction of the outer main girders 4 and 6 is shown as being jacked up, the jacks 23a and 23b are installed on the new girder bracket 18 to You may make it jack up the end of the girder which newly provided the notch part 17 of the girder 4 and 6. FIG. In this case, the jacks 23a, 23b on the new girder brackets 18 and the jacks 23c installed on the temporary jack-up cradle 19a are connected to the girder ends of the outer main girders 4, 6 and one end. By jacking up the cross beam 8a, it is possible to remove the existing girder brackets 9a and 9c and the existing supports 10 on the upper side, to remove the existing other side cross beam 8b, The girder 24b can be attached. The jacks 23a and 23b on the new girder brackets 18 and the jacks 23d installed on the temporary jack-up cradle 19b are connected to the girder ends of the outer main girders 4 and 6, and the new other By jacking up the end cross beam 24b, it is possible to remove the one existing end cross beam 8a and attach a new one end cross beam 24a. Thereafter, the newly installed end cross beams 24a and 24b are jacked up by the two jacks 23c and 23d on the temporary jack-up cradles 19a and 19b, and the jacks 23c and 23d By setting the state of receiving the loads related to all the main girders 4, 5, and 6, the jacks 23a and 23b on the new girder brackets 18 are replaced with the bearings 26, and then the jacks 23c and 23d are placed. By jacking down, the ends of the outer main girders 4 and 6 can be received on the upper side of the new support 26 installed on the new girder brackets 18.

  Moreover, the girder ends were provided with outer main girders 4 and 6 having a full web and a middle main girder 5 having a notch 7 at the girder end, and protruded on the bridge axial direction surface of the cross beam 3 of the steel pier 1. The upper end of the notch 7 of the middle main girder 5 and the end of the middle main girder 5 and the outer edge of the outer main girders 4 and 6 are connected to the girder brackets 9b, 9a and 9c. If the I-girder bridge of a certain type is configured to support the laterally-shifted portions of the cross beams 8a and 8b through the support 10, respectively, it can be applied to I-girder bridges other than the viaduct of the Metropolitan Expressway. Of course, various modifications can be made without departing from the scope of the present invention.

1 Steel bridge pier 3 Cross beam 4 Outer main girder 5 Middle main girder 6 Outer main girder 7 Notch 9a, 9b, 9c Girder bracket 8a, 8b End cross girder 10 Bearing 17, 17a, 17b Notch 18 New girder Bracket 19a, 19b Temporary jackup cradle (jack cradle)
21 Jack-up cradle 23a, 23b, 23c, 23d Jack 26 Bearing 27 Outer main girder outer reinforcing material (reinforcing material)
30 Outer main girder inner side reinforcement (reinforcement)
34a, 34b Middle main girder reinforcement (reinforcement)
35a, 35b Notch

Claims (3)

  The girder ends of each outer main girder located at both ends of the bridge width direction are full webs, and a notch is provided at the bottom of the girder end of the middle main girder located inside the bridge width direction. Girder ends provided with notches in the middle main girder on each girder bracket projecting at a required position in the bridge width direction on the bridge axis direction surface, and the girder end of the middle main girder adjacent to each outer main girder A notch is formed at the end of each girder of the above-mentioned outer main girder in the I-girder bridge, which is configured to support the outer girder in the bridge width direction of each end cross girder connecting the edges with each other via a support. Next, a new girder bracket that protrudes to the inside of the notch provided at the end of each outer main girder is provided at a position corresponding to each outer main girder in the bridge axial direction surface of the horizontal beam. In addition, each jack installed on the jack-up cradle protruding from the required portion on the bridge axial direction surface of the horizontal beam. In the state where each main girder is jacked up, the existing girder bracket for supporting each end girder and the existing support on the upper side are removed, and the upper side of the girder bracket for supporting the middle main girder is removed. Remove the existing support, and then place a new support on the upper side of the new girder bracket and the girder bracket for supporting the middle main girder, and then jack down each of the jacks. Then, the end of the girder in which the notch portion of each outer main girder is newly installed is used for each new girder bracket, and the end of the middle main girder is used for the girder bracket for supporting the middle main girder, respectively. A method of repairing an I-girder bridge, characterized in that it is supported through the new support.   When a notch is newly provided at the end of each outer main beam, a notch corresponding to the notch to be provided in the outer main beam is provided on both side surfaces of the end of each outer main beam in advance. 2. A reinforcing member is attached, and then the spar ends of the main girders are cut along the notches of the reinforcing members to form notches at the spar ends of the main girders. The repair method for the I-girder bridge described.   After attaching a reinforcing material having a notch portion that is slightly larger than the existing notch portion at both ends of the middle main girder end, the notch of each reinforcing material By cutting the web around the existing notch portion of the middle main girder along the portion, a notch portion reinforced by each reinforcing material is provided at the end of the middle main girder, and each reinforcing material 3. The I-girder bridge according to claim 1 or 2, wherein a girder end of the middle main girder provided with a notched portion reinforced by the above is supported on a girder bracket for supporting the middle main girder via a new support. Renovation method.

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