JP2011153430A - Safety barrier and reinforcing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for reinforcing a safety barrier, which controls the displacement direction and torsion of an H steel-made strut and secures a high strut reinforcing effect at low costs. <P>SOLUTION: In the safety barrier with H steel-made struts, a pair of torsion restriction rods are laid between upper portions of the adjacent struts. A power between the adjacent struts is transmitted by the pair of torsion restriction rods, regulating the displacement direction of the struts upon receipt of an impact only to a slope valley side. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technology for reinforcing a protective fence for falling rocks, avalanches, landslides, and the like, and more particularly, to a protective fence provided with an H steel support and a method for reinforcing the same.

  As described in Patent Document 1, a plurality of rope members are laid in multiple stages between H steel columns that are erected at intervals, and a wire mesh is laid between the rope materials. Guard fences with a structure that finally receives the impact of falling rocks acting on a part of the rope material with the strength of the support column are well known, and many fences are installed in the vicinity of roads, railways and the like.

FIG. 13 is a diagram modeling the displacement of the struts a ₁ and a ₂ and the rope members b _{1 to} b ₅ arranged in multiple stages when an impact is applied to the protective fence described in Patent Document 1. Both ends of each rope materials b ₁ ~b ₅ is fixed to the respective terminal post a _1, section between the ends of the rope materials b ₁ ~b ₅ is slidably mounted on the intermediate posts a _2.
In the protective fence described in Patent Document 1, when an impact c such as falling rocks acts, the displacement amount of each rope member b _{1 to} b ₅ increases from the lower stage to the upper stage of the pillars a ₁ and a ₂ , and each pillar a It has been confirmed in experiments and accident sites that ₁ and a ₂ are not only bent but also twisted (rotational moment).

  Further, Patent Document 2 discloses a method of expanding a large protective fence at a position close to an existing protective fence on the upstream side of a slope as a method for reinforcing an old protective fence.

JP-A-7-197423 (paragraph 0002, FIGS. 6 and 7) JP 2006-183326 A (FIG. 4)

The conventional guard fence has the following problems.
<1> In the guard fence described in Patent Document 1, the strength design of the H steel columns a ₁ and a ₂ is designed to bend toward the slope valley (perpendicular to the extension direction of the guard fence). It was only designed and not designed for bending in the extension direction of the guard fence.
For this reason, the protective fence is destroyed by a smaller impact than originally designed, and there is a serious defect that the protective performance cannot be fully exhibited.
<2> The reinforcement technique disclosed in Patent Document 2 has a problem that the extension cost of the large protective fence is increased and the construction period is long, and the existing protective fence itself cannot be reinforced.

<3> A protective fence including an H-steel post represented by Patent Document 1 is left with structural defects, and is aging.
Under such circumstances, there is a demand for a technique for reinforcing a protective fence including an H-steel strut that can be reliably reinforced at low cost.

The present invention has been made in view of the above points, and an object of the present invention is to propose a technique for reinforcing a protective fence that can reinforce an H-steel support column at low cost.
A further object of the present invention is to propose a reinforcement technique for a protective fence that can control the displacement direction and twist of the support column.

1st invention of this application is a guard fence which comprises the support | pillar made from H steel, a pair of torsional restraint rods are stretched between the upper parts of adjacent struts, and the force between adjacent struts is applied by the pair of torsional restraint rods. Provided is a protective fence that transmits and restricts the displacement direction of the support column at the time of receiving only to the slope valley side without being twisted.
The second invention of the present application is characterized in that, in the first invention, a mounting jig is fixed to the upper portion of the support column, and a pair of torsional restraint rods are stretched between the upper portions of the adjacent support columns via the mounting jig. Provide a protective fence.
According to a third invention of the present application, in the first invention or the second invention, a buffer fitting is provided near an intermediate portion or an end portion of the torsion restraint rod so as to locally stop load transmission through the torsion restraint rod. Providing a characteristic protective fence.
According to a fourth aspect of the present invention, there is provided the protective fence according to any one of the first to third aspects, wherein a reinforcing restraint frame is externally reinforced at the bottom part of the sloped valley of the support.
According to a fifth aspect of the present invention, in the guard fence having the H-steel struts, a pair of torsional restraint rods are stretched between the upper portions of adjacent struts, and the displacement of the struts at the time of impact by the pair of torsional restraint rods Provided is a method for reinforcing a protective fence, characterized in that the direction is restricted only to a sloped valley side without twisting.
According to a sixth aspect of the present invention, there is provided a method for reinforcing a protective fence according to the fifth aspect of the invention, wherein a reinforcing restraint frame is externally reinforced at the bottom part of the sloped valley of the support.

The present invention can obtain at least one of the following effects.
<1> By simply stretching a pair of torsional restraint rods between the upper parts of adjacent H-steel struts, the strength against the twisting of the struts can be increased by a large number of adjacent struts, and the impact force can be extended over a wide range. Dispersed, the impact performance as a protective fence is greatly improved.
<2> By merely stretching a pair of torsional restraint rods between the upper portions of adjacent struts, the displacement direction of the struts at the time of impact can be restricted only to the slope valley side without causing twisting.
<3> When the torsional restraint rod is stretched through the mounting jig, it is not necessary to apply any processing to the support column, and the torsional restraint rod can be stretched easily and in a short time.
<4> By providing the shock-absorbing fitting near the middle part or the end of the torsional restraint rod, the torsional restraint rod can slide at the time of impact, and the load transmission through the torsional restraint rod can be locally stopped.
Therefore, even if a large impact acts on the protective fence, it is possible to restrain the torsion of each support column while avoiding the breakage of the torsion restricting rod.
<5> When the reinforcing restraint frame is externally mounted on the bottom of the slope on the sloped valley side, the local buckling deformation of the pillar can be restrained, and the bending deformation resistance of the pillar can be enhanced.

It is explanatory drawing of the protection fence which concerns on this invention, (a) is the figure seen from the slope mountain side of a protection fence, (b) is a top view of a protection fence Sectional view of II-II in FIG. Perspective view of the top of the protective fence It is explanatory drawing of the reinforcement effect | action of a torsion restraint rod, (a) is a model figure of the guard fence before an impact acts, (b) is a model figure of the guard fence when an impact acts. In the explanatory drawing concerning Example 3, it is a top view of the guard fence before the effect | action of an impact Sectional view of VI-VI in FIG. Sectional view of VII-VII in FIG. Perspective view of single shock absorber Perspective view of double shock absorber It is explanatory drawing which concerns on Example 4, and is a perspective view of a reinforcement restraint frame. In explanatory drawing which concerns on Example 4, it is a side view of the skirt part of a support | pillar Sectional view of XII-XII in FIG. An illustration of a conventional guard fence, modeling the displacement of the struts and the rope material arranged in multiple stages when an impact is applied

  DESCRIPTION OF EMBODIMENTS Preferred embodiments for carrying out the invention will be described with reference to the drawings.

<1> Outline of Guard Fence FIG. 1 (a) shows a view of the guard fence to which the present invention is applied as viewed from the slope mountain side, FIG. 2 (b) shows a plan view thereof, and FIG. FIG. 3 is a perspective view of the upper part of the protective fence.

  The guard fence on which the present invention is premised is an H-steel support column 10 (including a terminal support column and an intermediate support column) standing upright at intervals, and a plurality of rope members horizontally mounted between these support columns 10 20 and a net 21 such as a wire mesh attached to the plurality of rope members 20.

  The column 10 is a steel material having a H-shaped cross section composed of a flange 11 and a web 12, and the lower part thereof is directly embedded in the concrete foundation 30 or the slope.

  Both end portions of each rope member 20 are fixed to terminal struts (not shown), and a section between the end portions of each rope member 20 is arranged on the slope mountain side of the intermediate strut 10 and is slid through a fixture 22 such as a U bolt. It is mounted movably.

  In the above-described known guard fence, the present invention has a plurality of torsional restraint rods 40 stretched between the upper portions of adjacent struts 10, 10, and these torsional restraint rods 40 change the displacement direction of the struts 10 at the time of impact. While restricting only to the valley side, the torsion of the column 10 is restrained.

<2> Torsional restraint rod The torsional constraint rod 40 is a rope material, a bar material, or a pipe material that has substantially the same length as the span of the support column 10 and has excellent tensile strength.
As a material of the twist restraint rod 40, for example, a rope material made of steel or high-strength fiber, or a rod material such as a reinforcing bar, a PC steel rod, or a pipe material such as a steel pipe can be used. In consideration of the rope material is preferable.
At both ends of the torsional restraint rod 40, connection portions 41 that can be connected to a mounting jig 50 described later are formed.

  Although not shown in the drawings, a length adjusting bracket such as a turn buckle is interposed in a part of the torsional restraint rod 40, or the end portion of the torsional restraint rod 40 and the connecting portion 41 are screwed together to form the torsional constraint rod 40 It is good to comprise so that the full length of can be adjusted.

<3> Mounting jig The mounting jig 50 shown in FIGS.
The mounting jig 50 is a jig that has both the function of connecting the torsional restraint rod 40 without applying any processing to the existing column 10 and the function of expanding the torque transmission length between the column 10 and the torsional restraint rod 40. A fitting portion 51 that is externally attached to the column 10 and an extension plate 52 that is integrally fixed to one end of the fitting portion 51 are provided.

The fitting portion 51 has a space 53 that can be fitted from above the column 10 having the flange 11 and the web 12. In this example, the case where the space 53 is formed in a T shape so that the fitting portion 51 does not interfere with the fixture 22 is shown, but if it does not interfere with the fixture 22, it is formed in a substantially H shape that matches the cross-sectional shape of the column 10. May be.
The fitting portion 51 is formed by bending a single plate body so as to cover the peripheral surface of the support column 10 having an H-shaped cross section. You may comprise with box steel.

  A plurality of fixing bolts 54 are screwed onto the plate surface of the fitting portion 51 in order to fix the mounting jig 50 to the support column 10.

  Attachment holes 55 are formed at the four corners of the expansion plate 52, and are structured to be connectable to the connection portion 41 of the torsional restraint rod 40 by connecting elements 56 such as bolts and pins.

<4> Method for Stretching Torsion Restraint Rod Next, a method for stretching a plurality of twist restraint rods 40 between the upper portions of adjacent columns 10 and 10 will be described.

<4.1> Attaching the mounting jig The mounting jig 50 is set by inserting the fitting portion 51 into the upper portion of each column 10 constituting the protective fence.
At this time, as shown in FIG. 3, the fitting portion 51 is covered so as not to interfere with the fixture 22 attached to the uppermost portion of the flange 11 of the support column 10.
When the mounting jig 50 is put on, a plurality of fixing bolts 54 provided on the fitting portion 51 are tightened to fix the mounting jig 50 to the upper portion of the column 10.

<4.2> Extension of torsional restraint rod The torsional restraint rod 40 is bridged between the attachment jigs 50 attached to the upper portions of the adjacent struts 10, and the connection portion 41 at the end of the torsional constraint rod 40 is attached to the attachment jig. The mounting holes 55 formed in the 50 expansion plates 52 are aligned, and both ends of the torsional restraint rod 40 are connected to the mounting jig 50 by connecting elements 56 such as bolts and pins.
The connecting portion 41 of each torsional restraint rod 40 is rotatably connected to the mounting jig 50 so as to allow relative displacement.

  Finally, as shown in FIG. 1B, two torsional restraint rods 40 are stretched between the upper portions of the adjacent columns 10 so as to be parallel to each other.

In the case of the intermediate support column 10, four torsional restraint rods 40 are connected to one mounting jig 50 on both sides thereof, and in the case of the terminal support column, one mounting jig 50 is connected to one side thereof. Two torsional restraint rods 40 are connected.
A pair of front and rear torsional restraint rods 40 are stretched between the upper portions of all the columns 10 or over a limited section requiring reinforcement, thereby completing the reinforcement of the protective fence.

  In this example, the torsional restraint rod 40 can be stretched via the mounting jig 50 attached to the upper part of the column 10, so that it is not necessary to perform any processing on the column 10, and the tensioning rod 40 can be easily stretched. Can be done in a short time.

<5> Action of torsion restraint rod 40 The reinforcement action of the torsion restraint rod 40 will be described with reference to FIG.
FIG. 4A shows a model view of the protective fence in plan view before the impact F such as falling rocks acts, and FIG. 4B shows a model diagram of the protective fence when the impact F acts.

When an impact F acts on the protective fence, a force directed toward the slope valley and a force directed in the extending direction of the protective fence are applied to the support column 10 located in the receiving section.
In the present invention, a pair of torsional restraint rods 40, 40 are stretched between the upper portions of adjacent struts 10 to reinforce the struts 10.
Therefore, since the force directed in the extension direction of the protective fence is supported by the adjacent strut 10 by a pair of torsional restraint rods 40, 40 stretched between the upper portions of the respective struts 10, the strut 10 located in the receiving section is It only displaces toward the slope valley without twisting.

In other words, the pair of torsional restraint rods 40, 40 restrains the torsion (rotational moment) of the column 10.
Since the displacement of the column 10 is transmitted to the column 10 other than the receiving section via the torsional restraint rod 40, all the columns 10 to which the force is transmitted are similarly displaced toward the slope valley side to protect the column. Displacement toward the extension direction of the fence is restricted.

Accordingly, the strut 10 that does not act on the torsion is subjected to a force directed toward the slope valley, and exhibits sufficient strength against bending deformation of the strut 10 as compared with the case where the torsional restraint rod 40 is stretched and not reinforced. can do.
Thus, the receiving performance as a protective fence is remarkably improved only by extending a pair of torsional restraint rods 40, 40 between the upper portions of the adjacent columns 10.

The control of the displacement direction of the column 10 will be described in detail with reference to FIGS. 4 (a) and 4 (b).
4 (a) is a plan view of the guard fence model before the action of the impact F, and FIG. 4 (b) is a plan view of the guard fence model after the action of the shock F. The lower part of the drawing shows the slope valley side.
4 (a), the overall length L ₁ of the inclined surface mountain and slope valley pair of before and after placement on the side twist restraining rod 40, 40 are both equal, also facing distance L ₂ between the end portions of the torsion constraint rod 40, 40 Both are equal. For this reason, as shown in FIG. 4A, before the action of the impact F, the two front and rear torsional restraint rods 40, 40 constitute the long sides of a planar regular square.

Also act impact F to the safety barrier, as shown in FIG. 4 (b), facing the distance L ₂ between the total length L ₁ and the end portion of the front and rear torsion constraint rod 40, 40 does not change.
That is, even if the impact F acts, the two front and rear twist restraint rods 40, 40 constitute the long side of the plane regular quadrangle or the long side of the plane parallelogram, and the torsion (rotational moment) of each column 10 Can be effectively restrained.

In the first embodiment, the case where the torsional restraint rod 40 is stretched via the attachment jig 50 attached to the upper portion of the column 10 has been described. However, the attachment jig 50 is omitted, and the torsional constraint directly on the flange 11 of the column 10. The heel 40 may be stretched.
Further, the position where the torsion restraint bar 40 is stretched is not limited to the uppermost part of the column 10, and may be stretched between the middle parts of the column 10.
If a plurality of sets of torsional restraint rods 40 are stretched in the height direction with respect to the column 10, the torsional constraint effect of the column 10 is further enhanced.

  Further, the present invention is not limited to an existing protective fence, and can be applied to a new protective fence.

  Based on FIGS. 5 to 9, load transmission through the torsional restraint rod 40 is locally performed by installing a shock-absorbing metal fitting in the middle or near the end of the torsional restraint rod 40 installed between the upper portions of the adjacent columns 10 and 10. An embodiment which is limited to the above will be described.

  FIG. 5 is a plan view of the protective fence before the impact action, FIG. 6 shows a cross section of the mounting jig 50 at the support column, and FIG. 7 shows a torsional restraint rod 40 installed between the upper portions of the adjacent columns 10 and 10. The cross section of the polymerization part is shown.

<1> Method of Tensioning Torsion Restraint Rod In this example, as shown in FIG. 5, each twist restraint rod 40 is slidably attached to the upper portion of the support column 10 via a single shock absorber 60.

The torsional restraint rods 40 provided on the respective struts 10 are superposed near the end portions, and the superposed portions are slidably connected via a double buffer fitting 63.
That is, two torsional restraint rods 40, 40 are arranged in the same line between the upper portions of adjacent struts 10, 10, and the overlapping portion of the two torsional restraint rods 40, 40 is a double buffer. It is stretched through a metal fitting 63 without any slack.

  In the present embodiment, the buffer metal fittings 60 and 63 are provided at both the intermediate portion and the end portion of the torsion restricting rod 40, but the buffer metal fitting 60 is provided at either the intermediate portion or the end portion of the torsion restricting rod 40. , 63 need only be deployed.

  The construction range of the torsional restraint rod 40 via the buffer metal fittings 60 and 63 can be partially applied to a part of the protective fence or can be applied over the entire length of the protective fence.

<2> Single Buffer Bracket 60 The single buffer bracket 60 illustrated in FIG. 8 is a restraint in which a central portion of a rectangular steel plate is bent into a substantially U shape so that one twist restraint bar 40 can be gripped. A plate 61 and a fastening bolt 62 capable of fastening both ends of the restraining plate 61 are provided. For example, a buffer fitting described in Japanese Patent No. 382836 can be used.

  The single shock-absorbing bracket 60 is overlapped on both ends of the extension plate 52 of the mounting jig 50, and a single torsion restraint rod 40 is gripped by the fixing force of the fastening bolt 62 that fixes the overlapped portion. When the tension (load) exceeding the gripping force is applied, the torsional restraint rod 40 is allowed to slide with respect to the support column 10.

<3> Double shock absorber 63 The double shock absorber 63 illustrated in FIG. 9 is a restraint in which a central portion of a rectangular steel plate is bent into a substantially U shape so that two twist restraint rods 40 can be gripped. It includes a plate 61, one or a plurality of partition plates 64 accommodated in the restraint plate 61, and tightening bolts 62 capable of fastening both ends of the restraint plate 61. For example, it is described in Japanese Patent No. 4024070. Can be used.

The overlapping portion of the two torsional restraint rods 40 is accommodated in the space in the restraint plate 61 constituting the double buffer metal fitting 63 with the partition plate 64 interposed therebetween, and both ends of the restraint plate 61 are tightened with the fastening bolts 62. Each torsional restraint rod 40 is gripped by tightening, and when a tension (load) exceeding this gripping force is applied, the two torsional restraint rods 40 can slide together to extend the entire length of the torsional restraint rod 40. It has become.
In order to allow elongation of the two restraint rods 40 that have been polymerized, it is necessary to previously form an extra length portion as a sliding allowance at the overlapping portion of the two twist constraint rods 40.

  The shock-absorbing bracket is not limited to the structure of the single or double shock-absorbing metal fittings 60 and 63 described above, and may have a structure that allows the torsional restraint rod 40 to slide when a certain level of tension is applied. Various publicly known shock-absorbing metal fittings can be applied.

<4> In operational view of a torsional restraint rod 4 (b), rectangle formed in the opposing distance L ₂ between the total length L ₁ and the end portion of the torsion constraint rods 40, 40 of the two front and rear, to the action of an impact F The deformation into a parallelogram is as described above.
When a larger impact F is applied, the space between adjacent struts 10 is narrowed when deforming into a parallelogram, and all the struts 10 on the outer side of the adjacent struts 10 are forcibly displaced, resulting in torsion. It is assumed that a large stress is generated in the restraint rod 40 and breaks.

In this embodiment, the torsional restraint rod 40 slides with respect to the support column 10 via the buffer metal fittings 60 and 63 in the above case, or is installed between the upper portions of the adjacent support columns 10 and 10. By extending the entire length of the torsional restraint rods 40, 40, it is possible to prevent transmission of a load through the torsional restraint rod 40.
Therefore, even if a larger impact F acts, the torsional restraint rod 40 slides between the buffer metal fittings 60 and 63 provided near the middle part or the end of the torsional restraint rod 40, so that the torsional restraint rod 40. It is possible to restrain the torsion (rotational moment) of each support column 10 while avoiding breakage of the support column 10.

The above description has been given of the case where the two front and rear torsional restraint rods 40, 40 are horizontally mounted between the upper portions of the adjacent columns 10. However, the slope mountain side is omitted from the column 10 and the restraint rod 40 is disposed only on the slope valley side. May be placed horizontally.
In the above-described embodiment, when the shock absorbing structure acts on the protective fence, a tensile force acts on the restraint rod 40 horizontally mounted on the slope valley side, and a compressive force acts on the restraint rod 40 horizontally mounted on the slope mountain side. Will act.
When the restraint rod 40 is made of a rope material, the rope-made restraint rod 40 does not generate a resistance against the compressive force.
Therefore, between the upper portions of adjacent struts 10 and at least on the sloped valley side where the tensile force acts, the torsional restraint rod 40 is horizontally mounted, which is economical because the number of torsional restraint rods 40 can be halved. In addition, it is possible to expect an effect of preventing the twisting of the column 10 equivalent to the above-described embodiment.

10 to 12 show another embodiment in which the reinforcing restraint frame body 70 is attached to the skirt portion of the support column 10 to further reinforce the support column 10.
FIG. 10 shows a perspective view of the reinforcing restraint frame 70, FIG. 11 shows a side view of the skirt portion of the support column 10, and FIG. 12 shows a cross-sectional view of the skirt portion of the support column 10.

<1> Reinforcement restraint frame body Reinforcement restraint frame body 70 is a member that reinforces the bottom part on the sloped valley side of the support column 10, has a U-shape, and a back plate 71 that can exteriorize the outer surface of one flange 11, L It is formed by two side plates 72 and 72 that can be externally straddled across the inner surface of one flange 11 and the side surface of the web 12, and forms a planar T-shaped space 74 inside.
A plurality of fixing bolts 73 are screwed onto the plate surfaces of the side plates 72 and 72 in order to fix the reinforcing and restraining frame body 70 to the support column 10.
In this example, the back plate 71 and the side plates 72 and 72 are welded and manufactured. However, a single band-shaped metal plate may be bent and formed so as to form a plane T-shaped space 74. .

<2> Installation Method of Reinforcement Restraint Frame Body The installation method of the reinforcement restraint frame body 70 will be described. The reinforcement restraint frame body 70 from above the support column 10 with respect to the flange 11 and the web 12 on the slope trough side at the bottom of the support column 10. Drop.
Since the planar shape of the space 74 of the reinforcing constraint frame 70 is formed in a substantially T shape in accordance with the cross-sectional shape of the support column 10, the reinforcement constraint frame body 70 includes the flange 11 and the web on the slope valley side at the bottom of the support column 10. 12 outer peripheral surfaces can be covered.
Finally, by tightening the fixing bolts 73 provided on the plate surfaces of the side plates 72, 72, the reinforcing and restraining frame body 70 is fixed to the skirt portion on the slope valley side of the support column 10, and the mounting of the reinforcing and restraining frame body 70 is completed.

<3> Action of Reinforcement Restraint Frame Generally, the support fence post is easily buckled on the sloped valley side, and the bottom of the support pillar 10 is considered to be a weak point.
As in the present embodiment, the reinforcing restraint frame 70 can be reinforced simply by mounting and fixing it to the bottom of the slope 10 on the sloped valley side.
Therefore, when the displacement on the slope valley side of the support column 10 is generated, the reinforcement restraining frame body 70 can restrain the buckling deformation of the support column 10 and can increase the bending deformation resistance of the entire support column 10.

  Considering the reinforcing effect of the entire protective fence, it is desirable to use the fourth embodiment together with the first to third embodiments. Good.

10 ······················································································································ Double shock-absorbing metal fittings 70 ... Reinforcement restraint frame

Claims (6)

In a protective fence equipped with an H steel column,
A pair of torsional restraint rods are stretched between the tops of adjacent columns,
Transmitting the force between adjacent struts by the pair of torsional restraint rods, and restricting only the slope valley side without twisting the displacement direction of the struts at the time of impact,
Guard fence.   2. The protective fence according to claim 1, wherein a mounting jig is fixed to an upper portion of the support column, and a pair of torsional restraint rods are stretched between the upper portions of the adjacent support columns via the mounting jig.   3. The protective fence according to claim 1 or 2, wherein a buffer fitting is provided near an intermediate portion or an end portion of the torsion restraint rod so as to locally stop load transmission through the torsion restraint rod.   4. The protective fence according to any one of claims 1 to 3, wherein a reinforcing restraint frame is externally reinforced at the bottom of the sloped valley side of the support column. In a protective fence equipped with an H steel column,
A pair of torsional restraint rods are stretched between the tops of adjacent columns,
It is characterized by restricting only the slope valley side without twisting the displacement direction of the column at the time of receiving by the pair of torsional restraint rods,
How to reinforce the protective fence.   6. The method of reinforcing a protective fence according to claim 5, wherein a reinforcing restraint frame is externally reinforced at the skirt portion on the sloped valley side of the support column.

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