JP2016079748A - Installation structure for bridge guard fence, base member for bridge guard fence, and installation method for bridge guard fence - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an installation structure for a bridge guard fence that ensures sufficient strength even with a narrow ground cover.SOLUTION: An installation structure for a bridge guard fence includes: a plurality of anchor bolts B1 fitted on a top surface of a ground cover W of a road bridge, in two or more rows in an extension direction of the ground cover; a base member 3 fixed to protrude outward in a bridge width direction from the ground cover W; a support post 1 fixed on the base member 3; and a transverse beam fitted on the support post 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an installation structure of a bridge protection fence, particularly a base member for the bridge protection fence, and an installation method of the bridge protection fence, which are particularly suitable for renewing an existing bridge protection fence.

  In recent years, serious accidents such as casualties have occurred due to damage to social infrastructure such as aging road structures. For this reason, renewal of aging social infrastructure is urgently needed, and this renewal is promoted by the government and local governments.

  Regarding the renewal method of the existing bridge guard fence related to this, for example, the method described in Patent Document 1 has been proposed by the applicant of the present application. This method first removes the existing bridge guard fence from the concrete ground cover, and further removes the portion of the existing anchor bolt protruding from the ground cover. Thereafter, a new anchor bolt (for example, post-installed anchor bolt) is installed on the ground cover, and a new bridge protection fence is attached to the ground cover.

  By the way, bridges managed by local governments (prefectures and municipalities) are formed with a narrower cover than the bridges managed by the government, for example, because the installation time is old or the bridge length is short. There are many. For such a narrow ground cover, conventionally, when updating an existing bridge guard fence, new anchor bolts cannot be installed in multiple rows in the direction of the ground cover extension. It was dealt with by embedding it deeply.

  However, when post-installed anchor bolts are installed on a narrow ground cover, it is necessary to embed the anchor bolts deeply in order to secure an effective shear area of concrete that can withstand vehicle collisions. Since it is low and the distance to the floor slab is small, there are many cases where it is difficult to install the anchor bolt with a sufficient embedding depth. For this reason, for example, when a vehicle collides with a guard fence for a bridge, the anchor bolt is pulled out from the ground cover by the force applied to the anchor bolt due to this collision, so that the guard fence for the bridge falls into the river and the vehicle There was also a problem that could fall into the river. Moreover, even if an anchor bolt can be installed, there are many cases where the building limit defined in the road structure ordinance cannot be secured due to the narrow width of the ground cover.

  In addition, there is a method of re-forming the widened ground cover after removing the existing ground cover, but because the construction becomes large, the construction period is long and traffic control is required over a long period of time. large. And since the weight of the widened ground cover increases from before the widening, the load on the bridge slab and the pier is increased.

  There is also a method to fix the bracket with anchor bolts on the outer surface of the bridge in the width direction of the bridge (the surface on the opposite side of the road facing the road or the surface on the river side) and attach a new strut to the bracket. However, since there is a possibility that a pulling load is always applied to the anchor bolt for fixing the metal fitting, there is a difficulty in safety and durability. And, in order to construct anchor bolts on the outer surface in the bridge width direction of the ground cover, it is necessary to assemble a temporary scaffold on the river, so the construction cost increases.

Japanese Patent No. 5190599

  In view of the above problems, the present invention provides an installation structure of a bridge protection fence, a base member for the bridge protection fence, and an installation method of the bridge protection fence that can sufficiently secure strength even in a narrow ground cover. The task is to do.

  The present invention provides a plurality of anchor bolts that are attached to the upper surface of a ground cover in a road bridge and are arranged in two or more rows in the extending direction of the ground surface, and project from the ground surface to the outside in the bridge width direction. The bridge guard fence installation structure includes a base member fixed by the plurality of anchor bolts, a support post fixed on the base member, and a lateral beam attached to the support post.

  The present invention also provides an anchor bolt mounting hole that is attached to the upper surface of a ground bridge in a road bridge and through which a plurality of anchor bolts arranged in two or more rows in the extending direction of the ground cover, and a bridge protection A pillar mounting bolt hole for attaching a fence post, and when fixed to the ground cover, one end is located outside the outer surface in the bridge width direction of the ground cover. It is a base member.

  According to these structures, a support | pillar can be displaced from a ground cover by providing a base member between a ground cover and a support | pillar. A sufficient amount of anchor bolts to be arranged in two or more rows in the extending direction of the ground cover on the top surface of the ground cover is sufficient even if the ground cover has a narrow width by the amount of the displacement. Space is reserved. For this reason, even if it is a narrow ground cover, a pillar can be fixed using a plurality of anchor bolts. Therefore, the column is fixed with sufficient strength by the plurality of anchor bolts.

  Further, the horizontal distance from the inner surface facing the road on the bridge in the ground cover to the position closest to the road among the horizontal beams is 250 mm or more, and at least of the plurality of anchor bolts within the range of the horizontal distance Some can be located.

  According to this configuration, it is possible to fix the column with sufficient strength and to easily install the guard fence for the bridge with a structure that conforms to the building limit specified in the road structure ordinance.

  Moreover, the said support | pillar is fixed with respect to the said base member by the fixing member, and the said fixing member can be located in the bridge width direction outer side rather than the said several anchor bolt.

  Further, the pillar mounting bolt hole of the base member can be positioned on the outer side in the bridge width direction when fixed to the ground cover than the anchor bolt mounting hole.

  According to these structures, the fixing member which fixes a support | pillar to a base member can be provided separately from an anchor bolt. For this reason, the fixed member can bear the deformation load of the base member, and the anchor bolt can bear the pull-out load that occurs when the vehicle collides with the bridge guard fence. Can be distributed. Therefore, there is a possibility that the embedding depth of the anchor bolt into the ground cover can be reduced as much as the load to be borne by the anchor bolt is reduced.

  Further, a base cover that covers the base member from above can be further provided.

  Moreover, the whole cover which covers a ground cover and the said base member from upper direction can be further provided.

  According to these structures, the beauty of the bridge guard fence can be improved, and corrosion of the base member and the anchor bolt can be suppressed. And even if it is a case where a vehicle runs on a base member, it can suppress that a vehicle is damaged.

  Further, a recess is formed around the anchor bolt mounting hole, and the recess includes a base member for a bridge guard fence that can accommodate the anchor bolt so that the plurality of anchor bolts do not protrude from an upper end of the recess. it can.

  According to this configuration, the anchor bolt can be prevented from protruding from the base member. For this reason, even if it is a case where a vehicle runs on a base member, it can suppress that a vehicle is damaged.

  The present invention also includes a step of embedding a plurality of anchor bolts in the ground cover, and disposing the base member on the ground cover, and fixing the base member to the ground cover by screwing a nut into the anchor bolt. A step of mounting the column to the base member by placing a column on the base member and screwing a nut into a bolt mounted in the column mounting bolt hole; A method of installing a guard fence for a bridge having a mounting process.

  According to this method, it is possible to provide a guard fence for a bridge in which a column is fixed with sufficient strength even in a narrow ground cover.

  According to the present invention, by providing the base member between the ground cover and the support column, the support column is fixed to the ground cover with sufficient strength. Therefore, it is possible to provide an installation structure of a bridge protection fence, a base member for the bridge protection fence, and an installation method of the bridge protection fence that can sufficiently secure strength even in a narrow ground cover.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a state in which a bridge guard fence (excluding horizontal beams) according to an embodiment is provided on a ground cover according to the present invention. The protection fence for the bridge (excluding the horizontal beam) is shown on the ground cover, (a) is a front view, (b) is a plan view, and (c) is a longitudinal section taken along line AA in (b). It is a surface figure (a horizontal beam is displayed with a dashed-two dotted line). The base member of the guard fence for the bridge is shown, (a) is a plan view, (b) is a right side view, (c) is a longitudinal sectional view taken along line BB in (a), and (d) is a bottom view. (E) is a longitudinal cross-sectional view of the CC arrow of (a). The reinforcement angle of the protective fence for bridges is shown, (a) is a front view, (b) is a longitudinal cross-sectional view of the DD arrow of (a). The state which provided the guard fence for bridges which concerns on embodiment provided with the base cover on the ground cover about this invention is shown, (a) is a front view, (b) is a top view. The state which provided the guard fence for bridges concerning the embodiment provided with the whole cover on the ground cover about the present invention is shown, (a) is a front view and (b) is a top view. It is the schematic shown in order for (a)-(f) about the installation construction method of the guard fence for bridges.

  Next, embodiments of the present invention will be described. Note that this embodiment is merely an example for understanding the present invention, and variations other than the present embodiment regarding the shape, structure, material, and the like of each part are within the scope of the present invention. It goes without saying that it is allowed.

  In the following description, the expression “front / rear / left / right” is based on the direction described in FIGS. 1 and 3A, and the expression “vertical direction” is based on the direction described in FIG.

  As the installation structure of the guard fence for bridges of this embodiment, it is comprised as shown in FIG.1 and FIG.2 (a)-(c), and the support | pillar 1 and the cross beam 2 (not shown in FIG. 1) also called "a handrail" ) Is combined with a base guard member 3 that functions as an attachment disposed between the ground cover W and the support column 1. Furthermore, as an installation structure of the guard fence for the bridge according to the present embodiment, it is in contact with the outer surface in the bridge width direction of the ground cover W (the surface opposite to the side facing the center of the road on the bridge and the rear surface in FIG. 1). A reinforcing angle 4 is provided. In the present invention, the reinforcing angle 4 is not essential, and an installation structure of a bridge guard fence without the reinforcing angle 4 may be configured.

  The base member 3 is made of cast iron (more specifically, made of ductile cast iron). However, the material of the base member 3 is not limited to this, and can be formed of various materials such as an aluminum casting, iron, and a stainless alloy. The base member 3 has a shape shown in FIGS. 3A to 3E, and has a plate shape that is substantially rectangular in plan view. When the base member 3 is disposed on the ground cover W as shown in FIG. 1 and FIGS. 2A to 2C, the base member 3 is positioned so that the front faces the road on the bridge, and the left-right direction is It is located in the extending direction (left-right direction) of the ground cover W. The base member 3 is fixed on the ground cover W so as to project outward from the ground cover W in the bridge width direction (front-rear direction).

  An anchor bolt mounting portion 31 is formed at a position near the front of the base member 3. Four anchor bolt mounting holes 311 are formed in the anchor bolt mounting portion 31 and are embedded in the ground cover W from the top surface of the ground cover W, so that the anchor bolt B1 mounted on the top surface of the ground cover W is attached to the anchor bolt B1. On the other hand, it is fastened with a nut. The anchor bolt B1 is embedded in the ground cover W so as to extend in the vertical direction. The anchor bolt mounting hole 311 is a long hole extending in the left-right direction, that is, a long hole extending along the extending direction (left-right direction) of the ground cover W when installed on the ground cover W. Thus, when the anchor bolt mounting hole 311 is a long hole, for example, when there is a reinforcing bar inside the ground cover W at a position where the anchor bolt B1 is to be installed, the anchor bolt B1 can be shifted and installed to avoid the reinforcing bar. .

  Although four anchor bolt mounting holes 311 are formed in the anchor bolt mounting portion 31 of the present embodiment, the number of anchor bolt mounting holes 311 formed is not limited to this. For example, the anchor bolt attachment portion 31 can be configured so that two anchor bolts B1 are attached so as to share one elongated hole formed as the anchor bolt attachment hole 311.

  The anchor bolt mounting portion 31 has a recess 312 as shown in FIGS. Two anchor bolt mounting holes 311 arranged in the front-rear direction are formed in one recess 312. Regarding the distance from the bottom surface 3a to the top surface 3b of the base member 3, the distance from the upper end of the recess 312 to the bottom surface 3a of the base member 3 is greater than the height at which the anchor bolt B1 protrudes from the top surface of the ground cover W. ing. Therefore, as shown in FIGS. 1 and 2A, the upper end portion of the anchor bolt B1 protruding from the ground cover W can be accommodated in the recess 312 and can be prevented from protruding from the upper surface 3b of the base member 3. . Therefore, it is excellent in aesthetics when the base member 3 is mounted on the ground cover W. Furthermore, even when the vehicle rides on the base member 3, it is possible to suppress the upper end portion of the anchor bolt B1 from hitting the tire, so that tire damage such as a burst hardly occurs.

  As for the bottom portion that supports the anchor bolt B1 in the recess 312, the plate thickness of the rear region 312 b is larger than the plate thickness of the front region 312 a as shown in FIG. The reason is based on the following assumptions. That is, the reaction force of the upper load of the support column 1 is received by the anchor bolt B1, but the rear anchor bolt B1 that is closer to the fulcrum (support mounting bolt B2 as a fixing member) is closer to the front side. This is because it is assumed that a larger reaction force is received than the anchor bolt B1 on the side, so that the reaction force is countered. Another reason for this is to cope with stress concentration caused by a sudden change in the longitudinal sectional shape at the rear end portion of the recess 312.

  A column attachment portion 32 is formed in the rear region of the base member 3. The upper surface of the column attachment portion 32 is shaped such that the lower end plate 11 of the column 1 can be disposed. A column mounting bolt hole 321 is formed in the column mounting portion 32, and a column mounting bolt B <b> 2 is mounted to fix the lower end plate 11 of the column 1. As shown in FIG. 3C, the base member 3 has a cross-sectional performance required from the bottom surface 3a to the top surface 3b in the column mounting portion 32, and the load of the column 1 and the cross beam 2 and, for example, strong wind The bending stress acting on the base member 3 due to the support column 1 and the cross beam 2 falling to the outside in the bridge width direction (rear) at the time of the vehicle or the collision of the vehicle, the bending of the base member 3 within the elastic range, It is possible to keep it below the proof stress value.

  Four column mounting bolt holes 321 are provided in the column mounting part 32. Of these, the two positioned forward are provided with a relatively small interval in the left-right direction, and the two positioned rearward are provided with a relatively large interval in the left-right direction. In addition, it is not limited to this, For example, two located in the front and two located in the back can also be provided at the same interval. As shown in FIG.3 (c), the column attachment bolt hole 321 has the enlarged part 321a expanded in the bottom face 3a side. As shown in FIG. 3D, the enlarged portion 321a has a shape having a flat surface 321b facing in the left-right direction when viewed from the bottom. When a hexagonal bolt is used as the post mounting bolt B2, as shown in FIG. 2 (c), the bolt head is positioned at the enlarged portion 321a. The bolt head is brought into contact with the flat surface 321b, thereby preventing the column mounting bolt B2 from rotating. For this reason, the support | pillar 1 can be fixed to the base member 3 only by screwing a nut from the upper surface 3b side with respect to the support | pillar mounting bolt B2. Although not shown, for example, the enlarged portion 321a is provided with a drop-off preventing mechanism for preventing the column mounting bolt B2 from falling out of the column mounting bolt hole 321 as shown in FIG. 7B. Even in this state, the column mounting bolt B2 is prevented from falling off.

  The column attachment portion 32 is located away from the anchor bolt attachment portion 31 at the rear (outside in the bridge width direction of the ground cover W). For this reason, by providing the base member 3 between the ground cover W and the support 1, the support 1 can be shifted from the cover W. Even if the ground cover W has a narrow width, it is arranged in such a manner that a plurality of (in the present embodiment) are arranged on the top surface of the ground cover so that there are two or more rows in the extending direction of the ground cover W. A sufficient space for attaching the four anchor bolts B1 is secured. The “two columns” includes a case where each column is composed of only one column. For this reason, even if it is the ground cover W with a narrow width | variety, the support | pillar 1 can be fixed using the some anchor bolt B1 arrange | positioned so that it may become 2 or more rows toward the extension direction of the ground cover W. Therefore, the support column 1 is fixed with sufficient strength by the plurality of anchor bolts B1.

  Further, the column mounting bolt B2 is provided separately from the anchor bolt B1. For this reason, it is assumed that the column mounting bolt B2 can bear the deformation load of the base member 3, and assuming this assumption, the anchor bolt B1 has a pulling load generated when a vehicle collides with the bridge guard fence. Since it can bear, the load burdened by the column mounting bolt B2 and the anchor bolt B1 can be dispersed. Therefore, it is considered that the embedding depth of the anchor bolt B1 into the ground cover W can be reduced by the amount of load that should be borne by the anchor bolt B1.

  Further, the anchor bolt B1 and the column mounting bolt B2 do not interfere with each other. Therefore, since the fixing of the base member 3 to the ground cover W and the fixing of the support column 1 to the base member 3 can be performed in separate steps, the bridge guard fence can be updated efficiently.

  Note that unlike the present embodiment, a part or all of the anchor bolt mounting hole 311 can also serve as the column mounting bolt hole 321. In this case, a part or all of the anchor bolt B <b> 1 can be used to fix the column 1 to the base member 3. However, in this case, in order to adapt to the construction limit of the road structure ordinance described later, for example, it is necessary to prepare a column 1 having a special shape. Therefore, as in this embodiment, the anchor bolt mounting hole 311 and the column mounting column are used. It is desirable to form it separately from the bolt hole 321.

  A reinforcement angle attachment hole 33 is formed behind the base member 3 and closer to the left and right ends than the column attachment portion 32. The reinforcing angle attaching hole 33 is a long hole extending in the front-rear direction, and is used when attaching the reinforcing angle 4.

  A rounded portion 34 having a constant curvature is formed at the front corner of the base member 3. Further, the front portion of the upper surface 3b of the base member 3 has a tapered shape that is inclined so as to descend forward as shown in FIG. Thus, the base member 3 having a tapered front portion can suppress the occurrence of impact and vibration of the vehicle even when the vehicle rides on the base member 3.

  As shown in FIGS. 3B, 3D, and 3E, hook recesses 35 are formed at both ends of the base member 3 in the left-right direction and at substantially the center in the front-rear direction. The hook recess 35 is used as a handle of an operator, and the base member 3 can be easily transported manually. Further, as shown in FIGS. 3C, 3D, and 3E, the meat stealing portion 36 that opens to the bottom surface side is formed at both the left and right end portions and the front portion that do not directly contribute to the load burden by the base member 3. This contributes to reducing the weight of the base member 3.

  The base member 3 is attached to the ground cover W as shown in FIG. 1 and FIGS. 2 (a) to 2 (c), the front end is located on the ground cover W as shown, and the rear end is the ground cover. Projects beyond W (outside in the width direction of the bridge). The column 1 attached in this state is in a state of being offset backward (outside in the bridge width direction) with respect to the ground cover W. Can be adapted to building limits.

  The strut 1 and the cross beam 2 can have the same structure as that conventionally used. A lower end plate 11 is provided at the lower end of the column 1. The lower end plate 11 and the base member 3 are fastened with a fixing member. For this reason, a bolt through hole 111 is formed in the lower end plate 11. In the present embodiment, the column mounting bolts B2 and nuts are used as the fixing members, but other fastening means may be used. Moreover, in this embodiment, although the hexagon bolt is used as the support | pillar mounting bolt B2, bolts other than a hexagon bolt can also be used. In some cases (specifically, when the base member 3 is formed of a weldable material), the lower end plate 11 can be welded to the base member 3. As shown in FIG. 2 (c), the cross beam 2 is attached to a recess formed in front of the support column 1, and as shown in FIGS. 5 (a) and 6 (a), in the extending direction of the ground cover W. Located along.

  In addition, it is also possible to comprise the support | pillar 1 and the base member 3 integrally, and in this structure, there exists an advantage that the effort which fixes the support | pillar 1 to the base member 3 can be saved. However, in this configuration, the weight of the combined body of the support column 1 and the base member 3 is larger than the respective weights, and in some cases, heavy equipment is required, and it is difficult to adjust the position of the support column 1 with respect to the ground cover W. There is a demerit that Further, when the support column 1 and the base member 3 are integrally formed, for example, even if only one of the support column 1 and the base member 3 is damaged, the entire structure must be replaced. Only damaged parts can be replaced. Accordingly, it is desirable that the support column 1 and the base member 3 are configured separately.

  Here, the road construction limit is defined in the road structure ordinance (decree). According to this, it is required that the structure be separated from the outer end of the roadway, that is, the inner surface of the ground cover W by 250 mm or more.

  When anchor bolts are installed on the ground cover W, sufficient pullout strength cannot be exhibited unless the anchor bolts B1 are arranged in a region surrounded by the reinforcing bars inside the ground cover W, particularly the hoop bars. On the other hand, it is difficult to adapt to the construction limit while arranging anchor bolts in this region, particularly in the case of the narrow ground cover W.

  In the present embodiment, since the column 1 can be offset rearward (outside in the bridge width direction) by the base member 3, the horizontal distance X from the inner surface of the ground cover W to the position closest to the road among the horizontal beams 2 (FIG. 2). (See (c)) can be 250 mm or more. For this reason, it is possible to easily satisfy the requirements of the road structure ordinance. In the present embodiment, all four anchor bolts B1 are located within the range of the horizontal distance X as shown in FIG. However, the present invention is not limited to this, and for example, at least a part of the plurality of anchor bolts such as the anchor bolt B1 positioned at the front can be configured to be positioned within the range of the horizontal distance X. As mentioned above, since the support | pillar 1 is offset back, the update of the protection fence in the bridge which has the narrow ground cover W can be accelerated | stimulated. Moreover, by using the base member 3, the column 1 and the cross beam 2 can be used as they are, without using a special shape for satisfying the building limit.

  Four anchor bolts B1 of this embodiment are used for each column 1. Three or five or more can also be used. Even if the embedding length of each anchor bolt B1 in the ground cover W is not increased, the burden load per anchor bolt B1 is reduced as the number of anchor bolts B1 increases. Sufficient pulling strength can be secured with a small embedding length. As the anchor bolt B1, a post-installed anchor such as a chemical anchor can be used.

  The reinforcing angle 4 is attached to the rear surface of the ground cover W (surface on the outer side in the bridge width direction) as shown in FIGS. As shown in FIGS. 4A and 4B, the reinforcing angle 4 is formed by welding a plurality of ribs 42 to a steel angle member 41 and reinforcing it. However, the material of the reinforcing angle 4 is not limited to this, and can be formed of various materials such as cast iron. Further, a nut 43 is fixed to one side of the angle member 41 by welding. An angle fixing bolt B3 is screwed into the nut 43. Since the reinforcing angle 4 can be attached to the base member 3 with only the angle fixing bolt B3, attachment is possible without assembling a temporary scaffold. The reinforcing angle 4 abuts on the rear surface of the ground cover W. Thereby, the bending stress which arises in the base member 3 when the support | pillar 1 tries to fall backward can be relieved. Moreover, since the compressive stress which the base member 3 gives to the ground cover W at the time of a vehicle collision can be reduced, damages such as chipping of the ground cover W due to the compressive load acting locally can be suppressed.

  The cover 5 can be attached so as to cover the base member 3. This cover 5 is formed of, for example, a synthetic resin, and can be implemented as a base cover 5a that covers only the base member 3 as shown by hatching in FIGS. 5 (a) and 5 (b). (A) It can also be implemented as the whole cover 5b which covers the upper part of the base member 3 and the ground cover W, as shown by hatching. The cover 5 can be attached by various means. For example, it can be performed by fitting to the base member 3, bolting, fixing to a rail installed on the ground cover W, or the like. In addition, the raw material of the cover 5 is not limited to this, For example, it can form with various raw materials, such as an aluminum alloy and steel.

  By providing the cover 5, the beauty of the bridge guard fence can be improved, and the corrosion of the base member 3 and the anchor bolt B1 can be suppressed. Further, even if the vehicle rides on the base member, it is possible to suppress damage to the vehicle, the base member 3, and the ground cover W. In particular, in the case of the whole cover 5b, the upper surface of the whole cover 5b can be made uneven, so that even if the vehicle rides on the base member, the tire of the vehicle is caught by the base member 3 portion. Can hardly be caused, so that the vehicle can be promptly guided on the road. Further, when the cover 5 is formed of a synthetic resin, the cover 5 hits a pedestrian or other structure even if the cover 5 is detached from the ground cover W due to a vehicle collision, strong wind, or river increase. The risk that arises during the process can be reduced.

  Next, an update method for an existing bridge protection fence, which is an example of a bridge protection fence installation method using the bridge protection fence according to the present embodiment, will be described. However, the construction order is not limited to the following description order, and the order can be appropriately changed. First, the pillars and lateral beams of the existing bridge protective fence are removed from the ground cover W. Next, among the existing anchor bolts embedded in the ground cover W, at least a portion protruding from the upper surface of the ground cover W is removed. If necessary, repair the surface of the ground cover W or the like. Next, as shown in FIG. 7A, four new anchor bolts B1 are embedded in the ground cover W. Next, as shown in FIG. 7 (b), the base member 3 that has been passed through the column mounting bolt B2 from below the column mounting bolt hole 321 is positioned on the ground cover W, and FIG. As shown, the nut N1 is screwed into the anchor bolt mounting hole 311 of the base member 3 through the anchor bolt B1. The nut N1 is temporarily fixed at this stage.

  Next, as shown in FIG. 7 (d), the support 1 is positioned on the support attachment portion 32 of the base member 3, and as shown in FIG. 7 (e), the bolt through hole 111 of the lower end plate 11 in the support 1. The nut N2 is screwed into the column mounting bolt B2 penetrating through the nut N2. The nut N2 is temporarily set at this stage. Next, as shown in FIG. 7 (f), the cross beam 2 is attached to the column 1. Thereafter, the positional relationship of each part is adjusted, and the nuts N1 and N2 screwed into the anchor bolt B1 and the column mounting bolt B2 and the bolts and nuts for mounting the horizontal beam 2 are finally tightened to complete. If necessary, a reinforcing angle 4 is attached below the base member 3. The reinforcing angle 4 may be attached to the base member 3 in advance, or may be attached to the base member 3 at the end of the process.

  As described above, in the present embodiment, the base member 3 acts as a “ground cover extending member” which is an attachment that extends the ground cover W rearward (outward in the bridge width direction). For this reason, even if it is the narrow ground cover W, the support | pillar 1 is attached with the anchor bolt B1 arrange | positioned so that it may become 2 or more rows toward the extension direction of the ground cover W (four in this embodiment). I can support it. Moreover, building limits can be secured. For this reason, safety is high while ensuring strength. Moreover, there is no need to reconstruct the ground cover W. In addition, since the work of renewal of the existing fence guard can be completed only on the ground cover W (it can be constructed only on the bridge), a temporary scaffold is installed behind (outside) the bridge on the river. There is no need, and the construction period can be shortened and the construction cost can be reduced. Moreover, since each member for carrying out the renewal construction method can be configured so that the worker can carry it by manpower, it is not necessary to use heavy machinery and construction costs can be reduced.

  In addition, the construction method of this embodiment is not limited only to the update of the existing bridge protection fence described so far. For example, a new bridge protection fence is provided for the ground cover W in which the bridge protection fence is not provided. It can also be applied when providing. Furthermore, this construction method can also be applied to the newly formed ground cover W.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to each said embodiment, A various change can be added in the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 1 Support | pillar 2 Horizontal beam 3 Base member 3a Bottom surface of base member 3b Upper surface of base member 311 Anchor bolt mounting hole 312 Recess 321 Support bolt mounting bolt hole 5a Base cover 5b Overall cover B1 Anchor bolt B2 Fixing member, support mounting bolt W Ground cover X Horizontal distance

Claims (9)

A plurality of anchor bolts attached to the upper surface of the ground cover in the road bridge and arranged in two or more rows in the extending direction of the ground surface;
A base member fixed by the plurality of anchor bolts so as to project outward from the ground cover in the bridge width direction;
A column fixed on the base member;
An installation structure of a guard fence for a bridge, comprising: a horizontal beam attached to the column. The horizontal distance from the inner surface facing the road on the bridge to the position closest to the road among the horizontal beams is 250 mm or more,
The installation structure of the guard fence for bridges according to claim 1, wherein at least a part of the plurality of anchor bolts is located within the range of the horizontal distance. The support column is fixed to the base member by a fixing member,
The installation structure of a guard fence for a bridge according to claim 1 or 2, wherein the fixing member is located on the outer side in the bridge width direction than the plurality of anchor bolts.   The installation structure of the guard fence for bridges in any one of Claims 1-3 further provided with the base cover which covers the said base member from upper direction.   The installation structure of the guard fence for bridges in any one of Claims 1-3 further provided with the whole cover which covers a ground cover and the said base member from upper direction. Anchor bolt mounting holes through which a plurality of anchor bolts that are attached to the top surface of the bridge in the road bridge and are arranged in two or more rows in the extending direction of the ground cover,
A post mounting bolt hole for mounting a bridge guard fence post,
A base member for a guard fence for a bridge, where one end is located outward from the outer surface in the bridge width direction of the ground cover when fixed to the ground cover.   The base member for a guard fence for a bridge according to claim 6, wherein the pillar mounting bolt hole is positioned on the outer side in the bridge width direction when fixed to the ground cover than the anchor bolt mounting hole. A recess is formed around the anchor bolt mounting hole,
The base member for a guard fence for a bridge according to claim 6 or 7, wherein the concave portion can accommodate an anchor bolt so that the plurality of anchor bolts do not protrude from an upper end of the concave portion. Embedding a plurality of anchor bolts in the ground cover;
A step of placing the base member according to any one of claims 6 to 8 on the ground cover, and fixing the base member to the ground cover by screwing a nut into the anchor bolt;
A step of mounting the column to the base member by placing a column on the base member and screwing a nut into the bolt attached to the column mounting bolt hole;
A method of installing a guard fence for a bridge, comprising attaching a horizontal beam to the support column.

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