JP2018021330A - Guard fence for bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a guard fence for a bridge properly plastically deformable to an impact load by a collision of a vehicle.SOLUTION: A front support part 4F and a rear support part 4R for constituting a support member 4 are integrated into a base member 2, and the front support part 4F and the rear support part 4R are integrated via a center pillar 3, and a column body 5 is integrated into the center pillar 3, and is integrated into the front support part 4F, and a fixing end to the base member 2 in the front support part 4F and the rear support part 4R is further positionally dislocated forward to the center pillar 3, and buckling strength of the column body 5 is set higher than buckling strength of the support member 4.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a bridge guard fence erected on the ground cover of a road bridge.

  This type of bridge guard fence is proposed in Patent Document 1. The bridge guard fence of Patent Document 1 includes a base member that is fixed to an upper surface of a road bridge via an anchor bolt, and a support member that is erected on the upper surface of the base portion. A lateral beam is attached to the support member.

JP, 2015-45162, A

  In this type of bridge guard fence, a large force in the pulling direction acts on the anchor bolt via the support member due to an impact load generated at the time of a vehicle collision, etc., and the anchor bolt buried portion of the ground may be damaged. .

  In order to prevent a large force in the pulling direction from acting on the anchor bolt, it is conceivable that the bridge guard fence is plastically deformed against an impact load.

  Therefore, an object of the present invention is to provide a bridge protection fence that can be appropriately plastically deformed against an impact load caused by a vehicle collision or the like.

  The guard fence for a bridge according to the present invention includes a base member fixed to an upper surface of a road bridge via an anchor bolt, a cylindrical column body, a middle column inserted in a lower portion of the column body, And a support member having a spacing support portion that is attached between the base member and the middle column and supports the column main body at a position spaced upward from the base member.

  In the above-described configuration, the column main body is supported by the separation support portion that supports the column main body at a position spaced upward from the base member in the support member between the base member and the middle column. For this reason, the column main body is supported at a position spaced upward from the base member via the support member, the strength of the cylindrical column main body is made higher than the strength of the support member, and the column main body is firmly attached to the middle column. When the support member receives an impact load on the column main body, the support member can be plastically deformed.

  In the bridge guard fence of the present invention, a structure in which the support body is erected integrally with the support member can be employed.

  If the column main body and the support member are integrated with each other like the bridge guard fence with the above configuration, the impact load received by the column main body can be easily transmitted to the support member.

  In the bridge guard fence of the present invention, a configuration in which the middle pillar is penetrated by the support member can be adopted.

  In the bridge guard fence having the above-described configuration, it is possible to secure the support strength of the column main body by the middle pillar by securing the bonding strength between the middle pillar and the supporting member by allowing the middle pillar to penetrate the supporting member.

In the bridge guard fence according to the present invention, the support member is fixed to the base member and extends in a plate shape extending upward, and extends backward from the upper portion of the first portion. A plate-shaped and integrally provided with the second portion having the spacing support portion,
The angle formed by the extending direction of the second portion with respect to the upper surface of the base member is an angle of 10 degrees that is a downward gradient from the front to the rear, and an angle of 30 degrees that is an upward gradient from the front to the rear. It is possible to adopt a configuration with an angle between.

  The bridge guard fence configured as described above includes a first portion fixed to the base member and a second portion extending rearward from the upper portion of the first portion, so that the support member is plasticized by the impact load received by the column main body. Deformed.

  In the bridge guard fence of the present invention, a configuration in which the first portion and the second portion intersect at an angle of 90 degrees or more can be adopted.

  In the bridge guard fence configured as described above, the first portion fixed to the base member and the second portion extending rearward from the upper portion of the first portion intersect at an angle of 90 degrees or more, and the support body supports the separation support portion. The support member is plastically deformed by the impact load received by the column main body by being supported by the second portion having the support.

  In the bridge guard fence according to the present invention, the support member further includes a third portion, and the third portion is fixed to the base member and disposed below the second portion with respect to the base member. A configuration in which a plate-like portion extending rearward is provided, the middle pillar passes through the second portion, and a lower end is supported by the third portion can be adopted.

  In the bridge guard fence configured as described above, the middle portion of the middle column is supported by the second portion, and the lower end of the middle column is supported by the third portion, so that the middle column is reliably supported.

  In the guard fence for a bridge according to the present invention, it is possible to adopt a configuration in which the column main body is formed of aluminum and the middle column is formed of a steel pipe.

  The bridge guard fence with the above configuration can meet demands such as weight reduction and longer life of the bridge guard fence as a whole.

  In the guard fence for a bridge according to the present invention, the support member can be appropriately plastically deformed against an impact load caused by a vehicle collision or the like, with the support body being supported by a support member different from the base member.

It is a left view which shows a base unit among the guard fences for bridges concerning 1st embodiment of this invention. The base unit is shown, (a) is a plan view and (b) is a bottom view. The base unit is shown, (a) is a front view, and (b) is a rear view. It is a perspective view which shows the base unit and a pillar part. It is a perspective view which shows the base unit, a column part, and a cross beam (two-dot chain line display). It is a left side view showing a base unit and showing a case where an intermediate force is moved rearward under external force. It is a left view which shows a base unit and a pillar part among the guard fences for bridges concerning 1st embodiment of this invention.

  Hereinafter, a bridge guard fence according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 6. The bridge guard fence according to the first embodiment can be applied to either an existing road bridge K or a new road bridge K.

  The bridge guard fence is provided on the ground cover W of the road bridge K as shown in FIG. The ground cover W is arranged along the bridge length direction at each of both ends in the width direction of the road bridge K. The bridge guard fence includes a base unit 1 that is fixed to the upper surface of the ground cover W, and a pillar portion that extends upward from the base unit 1.

  A plurality of base units 1 are provided by being arranged at a predetermined interval in the bridge length direction (specified as the lateral direction) on each cover W. The column portion is provided for each base unit 1. The bridge guard fence further includes a plurality of horizontal beams 6 (three are represented by two-dot chain lines in FIG. 5) that are fixed so as to extend over the respective column portions. Since each base unit 1 and each column part are the same structure, in FIG. 1 thru | or FIG. 6, one base unit 1 and a column part are represented, and description of each base unit 1 and each column part is substituted.

  The base unit 1 includes a base member 2, a support member 4, and a middle pillar 3. The base unit 1 is entirely made of steel. The base member 2 is placed and fixed on the upper surface (which is a plane) of the ground cover W. As shown in FIG. 2, the base member 2 is formed in a plate shape having a rectangular shape in plan view. The base member 2 is formed with anchor bolt mounting holes 21 at a plurality (four locations). The anchor bolt mounting holes 21 are formed at two positions in front of the front first portion 41 of the front support portion 4F described later, and at two positions on the left and right sides of the front first portion 41. Each anchor bolt mounting hole 21 is a long hole that is long in the width direction of the road bridge K, that is, a long hole that is long in the width direction of the ground cover W (specified as the front-rear direction). The base member 2 is fixed to the ground cover W by inserting the anchor bolt B1 embedded in the ground cover W into the anchor bolt mounting hole 21 and fastening the nut N to the protruding portion of the anchor bolt B1 with respect to the base member 2. ing.

  As shown in FIGS. 1, 3, and 4, the support member 4 is fixed to the base member 2. The support member 4 is attached between the base member 2 and the middle column 3, and is configured to support a column main body 5 described later at a position spaced upward from the base member 2. The support member 4 includes a front support portion 4F fixed to the front and rear positions of the base member 2, a rear support portion 4R corresponding to the third portion, and further includes an intermediate reinforcing portion 4C.

  The front support portion 4F is disposed on the front side (width direction center side) with respect to the rear support portion 4R, and the rear support portion 4R is disposed on the rear side (width direction outer side) with respect to the front support portion 4F. The front support portion 4F is formed by bending a plate-shaped steel material, and integrally includes a front first portion 41 and a front second portion 42. The lateral length of the plate-shaped steel material is smaller than the lateral length of the base member 2 and is set longer than the lateral length of the middle column 3 and a column main body 5 described later. The front first part 41 and the front second part 42 are set to the same length.

  The front first portion 41 is fixed to the upper surface 22 of the base member 2 so as to extend upward (along the vertical direction). Specifically, the lower end surface of the front first portion 41 is fixed to the horizontal center portion of the upper surface 22 of the base member 2 and the substantially central portion in the front-rear direction by welding.

  The front second portion 42 extends from the upper end of the front first portion 41 with an obtuse angle indicated by an angle θ <b> 1 with respect to the front first portion 41. The front second portion 42 has an inclination indicated by an angle θ2 and is inclined and extended so as to be higher toward the rear. That is, in the first embodiment, the front second portion 42 is inclined so as to be separated from the upper surface 22 of the base member 2 toward the rear. Further, the rear end position of the front second portion 42 is positioned further rearward beyond the rear end surface 23 of the base member 2.

  A separation support portion 43 that supports the middle column 3 is formed in the front second portion 42 so that the middle column 3 separate from the front support portion 4F can be inserted. The separation support portion 43 is a rectangular insertion hole portion through which the middle column 3 is inserted, and is a portion that supports a middle portion in the longitudinal direction of the middle column 3 at a position spaced upward from the base member 2. By allowing the middle pillar 3 to penetrate the front second portion 42, it is possible to secure the bonding strength between the middle pillar 3 and the front second portion 42, and to secure the supporting force of the column main body 5 (described later) by the middle pillar 3. ing. The separation support portion 43 is formed at a position closer to the rear of the front second portion 42, that is, at a position further shifted rearward with respect to the rear end surface 23 of the base member 2.

  The rear support portion 4 </ b> R is disposed at the same position in the lateral direction with respect to the front support portion 4 </ b> F and the base member 2. The rear support portion 4R is formed by bending a plate-shaped steel material, and integrally includes a rear first portion 410 and a rear second portion 420. This plate-shaped steel material is thicker than the steel material constituting the front support portion 4F. The lateral length of the rear support portion 4R is set to be smaller than the lateral length of the base member 2 and longer than the lateral lengths of the middle column 3 and the column main body 5. The rear first portion 410 and the rear second portion 420 are set to the same length.

  The rear first portion 410 is fixed to the rear end surface 23 of the base member 2 so as to extend upward (along the vertical direction). Specifically, the lower end portion of the rear first portion 410 is fixed to the lateral center portion of the rear end surface 23 of the base member 2 by welding. The upper end position of the rear first portion 410 is lower than the upper end position of the front first portion 41.

  The rear second portion 420 is extended rearward from the upper end of the rear first portion 410 and obliquely upward. That is, the rear second portion 420 is inclined so as to be farther away from the upper surface 22 of the base member 2, and is extended with an obtuse angle with respect to the rear first portion 410. The rear end position of the rear second portion 420 substantially coincides with the rear end position of the front second portion 42. The rear second portion 420 is at a lower position than the front second portion 42.

  The inclined upper surface of the rear second portion 420 is a support surface that abuts and supports the lower end of the middle column 3 inserted through the separation support portion 43. Specifically, the lower end surface of the middle column 3 is welded to the inclined upper surface of the rear second portion 420. Therefore, the lower end surface of the middle column 3 has the same inclination angle as the inclination angle of the inclined upper surface of the rear second portion 420. With this configuration, the middle column 3 is disposed at a position that is rearward with respect to the base member 2. Further, the middle column 3 is positioned above the base member 2 and is held by the front support portion 4F and the rear support portion.

  The intermediate reinforcing portion 4C is a rectangular plate-like body along the vertical direction. The intermediate reinforcing portion 4C is disposed between the front support portion 4F and the rear support portion 4R and in front of the middle column 3. The four sides of the intermediate reinforcing portion 4C are welded so as to be connected to the upper surface 22 of the base member 2, the rear surface of the front first portion 41, the lower surface of the front second portion 42, the front surface of the rear first portion 410, and the front surface of the middle pillar 3. Yes. According to this configuration, since the front support portion 4F and the rear support portion 4R are reinforced by the intermediate reinforcing portion 4C, the strength of the entire support member 4 can be increased. In the first embodiment, the support member 4 is provided between the base member 2 and the middle pillar 3 as described above.

  The middle pillar 3 is a single square steel pipe having a substantially square shape in cross section. The middle column 3 is inserted through the spacing support portion 43 along the vertical direction (vertical direction). A reinforcing plate 31 extending in the front-rear direction is provided at the upper end of the middle pillar 3. The middle plate 3 is reinforced by the reinforcing plate 31 so as not to be crushed in the front-rear direction by an impact load caused by a vehicle collision or the like. Since the middle column 3 is not crushed (not deformed) even if it receives an impact load, loosening of the fitting state of the column main body 5 with respect to the middle column 3 can be suppressed, and therefore the impact load can be transmitted to the support member 4 side. As shown in FIGS. 3 (a) and 3 (b), the front column fixing bolt hole 33 penetrates in two places in the lower part of the front surface of the middle pillar 3, and the rear column fixing bolt hole 34 penetrates in two places in the upper part of the rear surface. ing. A transverse beam fixing bolt hole 35 penetrates at one place on the front and rear surfaces of the middle pillar 3 at the same height.

  The column portion includes such a middle column 3 and the column main body 5. Therefore, in the first embodiment, the middle pillar 3 is a member that is also used as the base unit 1 and the pillar portion. A lateral beam 6 made of aluminum alloy is attached to the column main body 5.

  The column main body 5 is formed in a rectangular tube shape that is externally fitted to the middle column 3 from above. In order to ensure the support of the column main body 5 by the middle column 3, the overlapping dimension in the vertical direction of the middle column 3 and the column main body 5 may be greater than or equal to the cross-sectional dimension before and after the middle column 3 or the left and right sectional dimensions. preferable. For example, the overlapping dimension is set to be not less than twice and not more than twice the cross-sectional dimension. The buckling strength of the column main body 5 is set higher than the buckling strength of the support member 4. The column main body 5 is fitted to a protruding portion 30 that protrudes upward from the inclined upper surface of the front second portion 42 of the front support portion 4F in the middle pillar 3, and covers this outwardly. That is, the middle column 3 is inserted in the lower part of the column body 5.

  The column body 5 is formed to be sufficiently longer than the protruding portion 30 of the middle column 3. The lower end of the column main body 5 is in contact with the inclined upper surface of the front second portion 42 of the front support portion 4F, and the lower portion is firmly fixed to the protruding portion 30 by the mounting bolt B2 so as to follow the vertical direction. Therefore, the lower end surface of the column main body 5 has the same inclination angle as the inclination angle of the inclined upper surface of the front second portion 42. With this configuration, the column main body 5 is integrated with the support member 4.

  The column main body 5 is externally fitted to the middle column 3, and the middle column 3 is disposed at a position deviated rearward with respect to the base member 2, so that the column main body 5 is rearward with respect to the base member 2. It is placed at a position that is off. The column main body 5 is placed and supported in the vicinity of the separation support portion 43 on the inclined upper surface of the front second portion 42 in the front support portion 4F. The entire base unit 1 is made of steel, whereas the column main body 5 is made of an aluminum alloy.

  As shown in FIG. 5, the column main body 5 is formed by attaching a mounting bolt B <b> 2 from the outside using the front column fixing bolt hole 33 and the rear column fixing bolt hole 34. Further, a cross beam 6 is fixed to the column body 5. The lower one of the horizontal beams 6 is attached to the column body 5 by a bolt (not shown) penetrating the column body 5 and the middle column 3.

  In the bridge guard fence having the above-described configuration, the support member 4 is constituted by the front support portion 4F, the rear support portion 4R, the intermediate reinforcement portion 4C, and the middle pillar 3, and these are integrated. Thus, the column main body 5 is separated from the base member 2 upward and rearward and supported by the separation support portion 43. For this reason, when a vehicle collides with the column main body 5 or the cross beam 6 and an impact load is applied to the column main body 5, the impact load is easily transmitted to the support member 4.

  Since the support member 4 is composed of a combination of the front support portion 4F, the rear support portion 4R, the intermediate reinforcement portion 4C, and the middle pillar 3, the strength of the support member 4 is higher than that in the case where the support member 4 is composed of one member. It is easy to ensure, and therefore the column main body 5 can be reliably supported.

  On the other hand, each component member, in particular, the front support portion 4F and the rear support portion 4R can share the impact load. For this reason, compared with the case where the impact load is borne by one member, it is possible to set the buckling strength with respect to the impact load with a high degree of freedom.

  Thereby, when a predetermined impact load is applied to the column main body 5, the column main body 5 is not buckled, and the anchor bolt B1 fixing the base member 2 to the ground cover W is not pulled out. The support member 4 can be buckled to absorb the impact load. Here, the buckling strength is a strength corresponding to a stress when the member starts plastic deformation.

  Specifically, it is assumed that the column main body 5 along the vertical direction tilts backward when a predetermined impact load is applied due to a vehicle collision or the like. First, in the bridge guard fence in the first embodiment, the front support part 4F and the rear support part 4R constituting the support member 4 are integrated with the base member 2, and the front support part 4F and the rear support part 4R are It is integrated via the middle pillar 3. Further, the column body 5 is integrated with the middle column 3 and is integrated with the front support portion 4F. Furthermore, the fixed ends to the base member 2 in the front support portion 4F and the rear support portion 4R are displaced forward with respect to the middle column 3. The buckling strength of the column main body 5 is set higher than the buckling strength of the support member 4.

  Under this condition, a case will be described in which the column main body 5 receives a predetermined impact load and tilts backward, and the support member 4 buckles and absorbs the impact load. In the front support portion 4F, as shown in FIG. 6, both the front first portion 41 and the front second portion 42 are pulled rearward. That is, the front second portion 42 is pulled rearward, and the front first portion 41 along the vertical direction is inclined rearward with the fixed end to the base member 2 as a fulcrum. And since the separation distance from the front first part 41 is large as much as the separation support part 43 is disposed closer to the rear of the front second part 42, the bending moment accompanying the inclination of the column main body 5 is increased. 41 greatly acts on the fixed end to the base member 2.

  As a result, the front support portion 4F is buckled so that the angle (in this case, an obtuse angle) of the intersection between the front first portion 41 and the front second portion 42 increases. And since the front 2nd part 42 inclines so that it may leave | separate with respect to the upper surface 22 of the base member 2 back, and since it is extended with the obtuse angle with respect to the front 1st part 41, an intersection part is easy to spread. Further, the middle column 3 is inserted through a separation support portion 43 formed on the rear side of the front second portion 42. And since the separation | spacing support part 43 is a hole, in the area | region in which the separation | spacing support part 43 is formed among the front 2nd parts 42, stress concentration arises and it is easy to buckle. FIG. 6 shows a state in which the middle part in the longitudinal direction of the front second part 42 is deformed so as to be broken.

  The middle column 3 is positioned rearwardly with respect to the base member 2 and is mounted and fixed on the rear second portion 420 of the rear support portion 4R, and is integrated with the front support portion 4F. It is integrated. For this reason, the bending moment accompanying the inclination of the column main body 5 acts on the rear second portion 420 of the rear support portion 4 </ b> R at the fixed end to the base member 2. The rear support portion 4R is present at a position directly below the middle pillar 3, and in the region where the separation support portion 43 is formed in the front second portion 42, stress concentration occurs and the buckling portion 4R easily buckles. Is the fulcrum of the inclination of the middle pillar 3 (the pillar body 5), the lower part of the middle pillar 3 moves forward when the middle pillar 3 tilts backward. For this reason, the rear support portion 4R is configured to receive the rear first portion 410 and the rear second portion against the bending moment received around the fixed end of the rear first portion 410 to the base member 2 and the support of the intermediate reinforcing portion 4C. Buckling occurs so that the angle of the intersection of 420 narrows (the inclination with respect to the base member 2 becomes shallow), and the rear first portion 410 buckles forward around its fixed end.

  The rear support portion 4R is formed thicker than the front support portion 4F, and the intermediate reinforcing portion 4C connects the base member 2 and the middle column 3, so that the middle column 3 is inclined rearward. , The excessive inclination is suppressed. However, there is no reinforcing member on the lower rear side of the rear support portion 4R, and the space portion S is formed. For this reason, buckling of the rear support portion 4R is not excessively restricted.

  In the first embodiment, since the external force at the time of vehicle collision or the like is absorbed by the buckling (plastic deformation) of the front support portion 4F and the rear support portion 4R, the anchor bolt B1 that fixes the base member 2 to the ground cover W. The pulling force acting on the ground can be reduced, and damage to the ground cover W can be suppressed. If damage to the ground cover W can be suppressed, repair of the ground cover W becomes unnecessary or requires minimal repair. If it becomes so, it can recover | restore only by replacing | exchanging the damaged base unit 1, the support | pillar main body 5, and the cross beam 6, and can suppress the cost of restoration construction.

  The column main body 5 and the horizontal beam 6 are separate members from the base unit 1, and the column main body 5 and the horizontal beam 6 made of aluminum alloy are used. Thus, the freedom of material selection is high for the column main body 5 and the cross beam 6. Particularly in recent years, from the viewpoint of reducing the weight, aesthetics, or extending the life of the bridge protective fence as a whole, the support body 5 and the cross beam 6 made of aluminum alloy are customer demands and can meet customer demands.

  In this bridge guard fence, the front support portion 4F is provided with the front second portion 42, the rear support portion 4R is provided with the rear second portion 420, and the middle column 3 is displaced rearward with respect to the base member 2. The front second portion 42 and the rear second portion 420 are supported. By doing in this way, even if it is the existing ground cover W with a narrow front-rear width, it is possible to secure the building limit defined in the road structure ordinance.

  The present invention is not limited to the first embodiment, and various modifications can be made without departing from the gist of the present invention. The same applies to the specific configuration of each part. In 1st embodiment, the support member 4 illustrated the case where the front support part 4F and the back support part 4R were provided.

  However, the number of supporting members may be one as in the second embodiment shown in FIG. In the bridge guard fence in the second embodiment, the support member 4 formed by bending a single steel plate is used, and the first portion 41a is fixed to stand on the upper surface 22 of the base member 2, and the second portion 42a. Is extended rearward from the upper end of the first portion 41a. The second portion 42 a is formed with a spacing support portion 43 that inserts and supports the middle column 3 and supports and fixes the lower end of the column main body 5 inserted into the middle column 3.

  In each said embodiment, the case where the support member 4 was made to insert and support the middle pillar 3 was illustrated. However, if the support member 4 includes a spacing support portion that supports the column main body 5 at a position spaced upward from the upper surface 22 of the base member 2, the middle pillar 3 is not necessarily inserted through the support member 4. Also, it is only necessary to be placed and fixed on the support member 4.

  In the first embodiment, as the front support portion 4F, the front second portion 42 is inclined so as to be separated from the upper surface 22 of the base member 2 toward the rear, and is extended with an obtuse angle with respect to the front first portion 41. The case is illustrated (the same applies to the rear support portion 4R). However, the front second portion 42 is not limited to a configuration that extends at an obtuse angle with respect to the front first portion 41. For example, as shown in FIG. 7 as the second embodiment, the angle formed by the front first portion 41 and the front second portion 42 may be 90 degrees.

  Alternatively, in the first embodiment, the case where the front second portion 42 is inclined away from the upper surface 22 of the base member 2 toward the rear and is extended with an obtuse angle with respect to the front first portion 41 is illustrated. . However, referring to FIG. 1, the angle θ1 in the extending direction of the front second portion 42 (or the rear second portion 420) with respect to the surface direction of the upper surface 22 of the base member 2 is a downward slope from the front to the rear. Can be selected in a range of 40 degrees, which is between an angle of 10 degrees and an angle of 30 degrees that is an upward gradient from the front to the rear. Further, preferably, the direction of the front second portion 42 (or the rear second portion 420) with respect to the surface direction of the upper surface 22 of the base member 2 is an upward gradient of 30 degrees or less from the direction parallel to the upper surface 22 toward the rear. This is the range.

  Regarding the angle θ1 of the front second portion 42 with respect to the base member 2 and the setting of the mutual angle θ2 between the front first portion 41 (or rear first portion 410) and the front second portion 42 (or rear second portion 420), It is not necessary to satisfy both the conditions of the angle θ1 being in the range of 40 degrees and the angle θ2 being the obtuse angle, and it can be set so as to satisfy only one of the conditions. For this reason, for example, the front first portion 41 and the front second portion 42 may intersect at an acute angle. In other words, in the above embodiment, the front first portion 41 (or the rear first portion 410) is not erected on the upper surface 22 of the base member 2 along the vertical direction, but the front first portion 41 (or the rear first portion 410). You may make it stand in the base member 2 so that it may incline ahead or back, so that the upper part may be.

  The inclination angle of the front first portion 41 (or the rear first portion 410) with respect to the upper surface 22 of the base member 2 is within a range of 10 degrees in the front-rear direction with respect to 90 degrees, so that the support member 4 is appropriately buckled. Therefore, it is preferable. In order to ensure the ease of buckling of the support member 4 when the front first portion 41 and the front second portion 42 intersect at an acute angle, the angle θ2 is preferably less than 90 degrees and 70 degrees or more. By setting the angles θ1 and θ2 as described above, it is easy to set the support member 4 to an appropriate buckling strength in order to tilt the column main body 5 backward.

  In the first embodiment, the front first portion 41 of the front support portion 4F and the rear first portion 410 of the rear support portion 4R are substantially parallel, and the front second portion 42 of the front support portion 4F and the rear support portion 4R are rearward. The case where it was made substantially parallel with the 2nd part 420 was illustrated. However, the present invention is not limited to this, and the front first portion 41 and the rear first portion 410 may not be parallel, and the front second portion 42 and the rear second portion 420 may not be parallel.

  In each said embodiment, the case where the square steel pipe which is cross-sectional view substantially square was used as the middle pillar 3 was illustrated. However, the intermediate pillar 3 may have various shapes such as a circular tube, a rectangular tube having a substantially rectangular cross-sectional view, a channel material, and a solid material.

  In each said embodiment, the case where it formed in plate shape about the 1st parts 41 and 410 and the 2nd parts 42 and 420 in the supporting member 4 was illustrated. However, on the premise that the separation support portion 43 can be secured, at least one of the other shapes such as a rod shape may be used.

  Furthermore, by arranging a reinforcing material or the like in the space portion behind the rear support portion 4R, the rear support portion 4R can be reinforced and the support force can be adjusted with respect to the impact load. The intermediate reinforcing portion 4C can be omitted.

  In 1st embodiment, the lower end surface of the middle pillar 3 illustrated the structure mounted and fixed to the rear 2nd part 420 of 4 R of back support parts. Thus, since the middle pillar 3 is not penetrated by the rear second portion 420 of the rear support portion 4R, it is possible to make the size of the rear second portion 420 smaller than the cross-sectional dimension of the middle pillar 3. However, from the viewpoint of securing strength, it is preferable to fix the lower end surface of the middle column 3 to the rear second portion 420 over the entire cross-sectional dimension.

  A drainage hole penetrating in the vertical direction can be formed at the front end portion of the rear support portion 4R in the rear second portion 420 (near the continuous portion with the rear first portion 410). Since the drainage holes can drain rainwater or the like that has entered the column portion, corrosion of the base unit 1 can be suppressed.

  In each said embodiment, the case where the anchor bolt attachment hole 21 formed in the base member 2 was made into a long hole long in the width direction of the bridge K for roads was illustrated. However, the anchor bolt mounting hole 21 is provided so that the position of the anchor bolt B1 can be dealt with when the reinforcing bar embedded in the ground cover W or the floor slab (slab) of the road bridge K is avoided. It may be a long hole along the bridge length direction. Alternatively, the anchor bolt mounting hole 21 may be a combination of a long hole along the width direction and a long hole along the bridge length direction.

  In each of the above embodiments, the overlapping dimension in the vertical direction of the middle column 3 and the column main body 5 is the cross-sectional dimension before and after the middle column 3 or the left and right cross sections in order to ensure the support of the column main body 5 by the middle column 3. The case where it is set to be not less than twice the dimension and not more than 2 times is illustrated. However, the overlap dimension is not limited to be not less than twice the cross-sectional dimension and not more than two times, and is a dimension exceeding twice the cross-sectional dimension on the assumption that the column main body 5 can be reliably supported by the middle pillar 3. There may be.

  DESCRIPTION OF SYMBOLS 1 ... Base unit, 2 ... Base member, 3 ... Middle pillar, 4 ... Support member, 4C ... Intermediate reinforcement part, 4F ... Front support part, 4R ... Back support part, 5 ... Post body, 6 ... Cross beam, 21 ... Anchor Bolt mounting hole, 22 ... upper surface, 23 ... rear end face, 30 ... projecting part, 41 ... front first part, 42 ... front second part, 43 ... separation support part, 410 ... rear first part, 420 ... rear second part, B1 ... Anchor bolt, S ... Space, W ... Ground cover

Claims (7)

A base member fixed to the upper surface of the road bridge via anchor bolts;
A cylindrical support body,
A middle column inserted in the lower part of the column body;
A support member that is attached between the base member and the middle post and has a spacing support portion that supports the column main body at a position spaced upward from the base member;
Guard fence for bridges characterized by comprising   The bridge guard fence according to claim 1, wherein the column main body is erected integrally with the support member.   The bridge fence according to claim 1 or 2, wherein the middle pillar is penetrated by the support member. The support member is fixed to the base member and has a first portion formed in a plate shape extending upward, a plate portion extending backward from the upper portion of the first portion, and A second part having a spacing support part integrally;
The angle formed by the extending direction of the second portion with respect to the upper surface of the base member is an angle of 10 degrees that is a downward gradient from the front to the rear, and an angle of 30 degrees that is an upward gradient from the front to the rear. The guard fence for a bridge according to any one of claims 1 to 3, wherein an angle between them is set.   The bridge guard fence according to claim 4, wherein the first part and the second part intersect at an angle of 90 degrees or more. The support member further comprises a third portion;
The third portion includes a plate-like portion that is fixed to the base member and is disposed below the second portion and extends rearward with respect to the base member.
The bridge fence according to claim 4 or 5, wherein the middle pillar penetrates the second part and a lower end is supported by the third part.   The bridge guard fence according to any one of claims 1 to 6, wherein the column main body is formed of aluminum, and the middle column is formed of a steel pipe.

Images