JP4399642B2 - Method for reinforcing steel structural members - Google Patents

Description

  The present invention relates to a reinforcing method for seismically reinforcing a steel structural member of an existing truss structure such as a communication tower or a power transmission tower.

  As shown in Fig. 2 (a), seismic reinforcement of angle steel for truss structures such as steel towers is performed by drilling an existing member 50 made of angle steel and adding material made of angle steel or steel plate (reinforcement steel). A method of overlapping 51 and fixing with bolts is conceivable. However, this may reduce the effective cross-sectional area due to the added bolt hole, which may lead to a decrease in the tensile strength of the existing member. Further, as shown in FIG. 2B, the existing member 50 has accessories such as a step bolt 52, and the attachment material 51 cannot be overlapped.

  In addition, it is also possible to improve the buckling strength by directly bonding the attachment material to the existing member with an adhesive, but if the existing member has been painted or galvanized, it will be peeled off during load resistance. Therefore, there is a possibility that the predetermined proof stress cannot be exhibited, and in order not to cause peeling, it is necessary to remove paint or galvanization.

  Patent Documents 1 and 2 are prior art related to the present invention. The invention of Patent Document 1 relates to a method for reinforcing the buckling strength of an existing truss structure composed of a shape steel or a steel pipe, and recalculates a structural calculation that takes into account the load of a new heavy object to be mounted on the existing truss structure. From these results, we determined the weak point truss members that would cause the compressive stress to exceed the safe buckling strength, completely removed the rust preventive paint for each, and made the angle steel of the required length the same material as the weak point truss member Attach the attachment material to the trough side surface of the weak point truss member of angle iron, or sandwich the attachment material of the half steel pipe to the weak point truss member of the steel tube, adhere with epoxy resin, and clamp with appropriate clamping means In addition, the truss loading capacity is improved by the weak cross-section truss member and the variable cross-section compression material.

  The invention of Patent Document 2 relates to a seismic reinforcement method for an existing column beam frame in which a brace such as a steel frame is installed and reinforced on an existing column beam frame made of reinforced concrete or steel reinforced concrete. The steel plate is fixed to the column by abutting a steel plate with a convex cross section so that at least the part where the brace is attached protrudes from the column surface, and winding the high-strength fiber sheet along the column surface and the outer surface of the steel plate while bonding them. Then, concrete is filled in the space between the column surface and the inner surface of the steel plate, and the end of the brace is attached to the outer surface of the steel plate.

JP-A-6-330643 Japanese Patent Laid-Open No. 10-184031

  As described above, in the seismic reinforcement of truss structure angle steel, the method of overlapping the attachments with bolts may reduce the effective cross-sectional area due to the added bolt holes, leading to a decrease in the tensile strength of existing members. In addition, there is a problem that reinforcement cannot be performed when there is an accessory such as a step bolt in the existing member. In addition, the method using an adhesive has a problem that it is necessary to remove paint or galvanization in order not to cause peeling.

  The present invention has been made to solve the above-described problems. When reinforcing an existing member of a truss structure with an attachment, there is no use of a bolt, and there is an accessory such as a step bolt on the existing member. Even in this case, it is possible to attach an auxiliary material to the existing member, and it is possible to securely fix the auxiliary material to the existing member regardless of the presence or absence of painting, galvanization, etc., and to improve the yield strength of the existing member with certainty It aims at providing the reinforcement method of the steel structural member which can be made to be made.

  The invention according to claim 1 of the present invention is an open section steel material (an angle steel, a channel shape steel, an H shape steel, etc.) such as an angle steel which is a steel structure member of a truss structure (a communication tower, a transmission tower, etc.) This is a method of reinforcing steel with open cross-section steel, and reinforcing steel (such as angle steel or steel plate) as an attachment is attached so as to form a closed cross-section by closing a pair of open ends of the open cross-section steel. It is characterized by fixing open-section steel and reinforcing steel by winding in the circumferential direction while adhering high-strength fiber sheets (sheets of flexible polyester fibers, carbon fibers, etc.) to the outer surface of the steel and the outer surface of the reinforcing steel This is a method for reinforcing a steel structural member.

  The present invention does not reinforce the existing open-section steel such as angle-shaped steel by superimposing reinforcing steel such as angle-shaped steel or steel plate, but reinforces the open-section steel such as angle-shaped steel or steel plate. Are attached so as to cover them to form a closed cross section. In the column material, when a compressive force is applied, the compressive force is not directly transmitted to the reinforcing steel material as the accessory material, but the yield strength is improved by restraining buckling.

  The high-strength fiber sheet may be provided over the entire length of the reinforcing steel material, but the effect of stiffening the existing member can be obtained only by providing the reinforcing steel material at, for example, both end portions and the intermediate portion. For example, an epoxy resin adhesive is used for bonding the fiber sheet, and the adhesive is applied between the fiber sheet and the open section steel material and the reinforcing steel material, so that the existing member can be bonded to the existing member regardless of the surface finish of the existing member. Reinforced steel can be held by adhesive force.

  The invention according to claim 2 of the present invention is the method for reinforcing a steel structural member according to claim 1, wherein the high-strength fiber sheet is wound around the outer surface of the open-section steel material and the outer surface of the reinforcing steel material more than twice. It is a method for reinforcing a steel structural member, characterized in that an adhesive is also applied between high-strength fiber sheets. If the adhesive is also applied between the high-strength fiber sheets wound more than twice, the reinforcing steel material can be reliably fixed to the existing member regardless of the surface finish of the existing member.

  According to a third aspect of the present invention, in the method of reinforcing a steel structural member according to the first or second aspect, a closed cross section having a square cross section is formed by the open section steel material of the angle steel and the reinforcing steel material of the angle steel. It is the reinforcement method of the steel structure member characterized by the above-mentioned. That is, this is a case where a closed cross section having a square cross section is formed by angle iron and angle steel.

  According to a fourth aspect of the present invention, in the method for reinforcing a steel structural member according to the first or second aspect, a closed cross section having a triangular cross section is formed by the open section steel of the angle steel and the reinforcing steel of the steel sheet. This is a method for reinforcing a steel structure member. That is, this is a case where a closed cross section having a triangular cross section is formed by angle steel and a steel plate.

  The invention according to claim 5 of the present invention is the method for reinforcing a steel structural member according to any one of claims 1 to 4, wherein a stiffening plate material orthogonal to the material axis is provided inside the reinforcing steel material. A steel structure member reinforcing method is provided, wherein stiffeners are attached at a predetermined interval in a material axis direction. That is, the stiffening plate material is disposed at, for example, a place where the fiber sheet is wound, and the end surface is brought into contact with the inner surface of the open-section steel material and is fastened with the fiber sheet to prevent the reinforcing steel material from being displaced.

  (1) A bolt is attached to an existing open steel such as an angle iron to form a closed cross section by attaching a reinforcing steel material such as an angle steel or a steel plate as a lid, and a high-strength fiber sheet is wound to reinforce. It is possible to reinforce by attaching an attachment without using it and without drilling. There is no reduction in the effective cross-sectional area due to the bolt holes, and the strength of existing steel structural members can be prevented from being reduced.

  (2) Since the reinforcing steel material is attached so as to cover it, it can be reinforced even if there is an accessory such as a step bolt on the existing open-section steel material such as angle iron.

  (3) Since the existing open-section steel material and the reinforcing steel material are fixed with a high-strength fiber sheet, the strength against peeling can be ensured regardless of whether the existing open-section steel material is coated or galvanized. There is no need to remove paint or galvanization, and the cost can be reduced.

  (4) Reinforced steel can be securely fixed to existing steel structural members by applying an adhesive between high-strength fiber sheets that are wound more than twice around the outer surface of the open section steel and the outer surface of the reinforcing steel. The buckling strength of existing steel structural members can be improved.

  (5) Since the reinforcement steel is added to the existing open-section steel and stiffened against buckling, the strength of the existing steel structural members is expected to increase even if the stress sharing to the accessory is small. it can.

  (6) By providing a stiffening plate on the reinforcing steel material as the accessory, it is possible to prevent the reinforcing steel material from slipping.

  Hereinafter, the present invention will be described based on the illustrated embodiments. This embodiment is an example applied to reinforcement of steel structural members such as main pillars and diagonal members of communication towers and power transmission towers. FIG. 1 shows an example in which the reinforcing method of the present invention is applied to a steel tower main pillar material. FIG. 2 shows the difference between the conventional reinforcing method and the present invention.

  In FIG. 1, an existing member 1 of a steel tower main pillar is angle steel as an open section steel material, and a gusset plate 2 to which diagonal materials are attached is attached to the angle steel existing member 1 at a predetermined interval in the material axis direction. The space between the upper and lower gusset plates 2 and 2 is a reinforcing section.

  In this reinforcing section, the reinforcing steel material 3 as an auxiliary material is attached to the existing angle steel member 1 so that the open ends of the pair of flanges 1a, 1a of the existing angle steel member 1 are closed to form a closed cross section. The angle steel existing member 1 and the reinforcing steel material 3 are fixed by winding the high strength fiber sheet 4 around the outer surface of the existing member 1 and the outer surface of the reinforcing steel material 3 in the circumferential direction while adhering the high strength fiber sheet 4 with an adhesive. When a compressive force acts on the column material, the compressive force does not act directly on the reinforcing steel material 3, but the reinforcing steel material 3 acts as a stiffener and restrains buckling to improve the yield strength.

  Angle steel is used for the reinforcing steel material 3, and the open ends of the pair of flanges are butted against the open ends of the pair of flanges of the existing member 1 to form a closed section with a square cross section (FIG. 1). d) and (e)). Alternatively, a steel plate is used, and the inner surfaces of both sides are butted against the open ends of the pair of flanges of the existing angle steel member 1 so that a closed cross-section with a right-angled isosceles triangle is formed (FIG. 1 (f), (g )reference).

  The high-strength fiber sheet 4 does not need to be provided over the entire length of the reinforcing section. By providing the high-strength fiber sheet 4 at both ends of the reinforcing steel material 3 and its intermediate portion, the effect of stiffening the existing angle steel member 1 can be obtained. The high-strength fiber sheet 4 is made of a flexible polyester fiber or carbon fiber sheet and bonded using an epoxy resin adhesive or the like. This adhesive is applied not only between the fiber sheet 4 and the steel materials 1, 3 but also between the fiber sheets 4, 4 wound twice or more, so that the surface finish of the existing member 1 for the angle iron is achieved. Regardless, the adhesive force can be maintained.

  Stiffener plates (stiffeners) 5 orthogonal to the material axis direction are attached to the inner surface of the reinforcing steel material 3 at both end portions and intermediate portions in the material axis direction, and the end surfaces of the stiffening plate material 5 are applied to the inner surface of the existing angle steel member 1. By contacting and binding with the fiber sheet 4, the displacement of the reinforcing steel material 3 is prevented. When the reinforcing steel material 3 is an angle steel, the stiffening plate material 5 has a square planar shape, and when the reinforcing steel material 3 is a steel plate, the planar shape is a right triangle. In any case, the corners of the stiffening plate 5 are chamfered to avoid the corners of the existing angle steel member 1.

  According to the present invention, a reinforcing steel material 3 such as an angle steel or a steel plate is attached to the existing angle member 1 so as to cover it to form a closed cross section, and the high strength fiber sheet 4 is wound and fixed. As described above, the reinforcing material can be reinforced without using a bolt or drilling. Further, since the reinforcing steel member 3 is attached to the existing angle member 1 so as to cover it, as shown in FIG. 2, even if the existing angle member 1 has an accessory such as a step bolt 52, the reinforcement is possible. It is. Moreover, since the angle steel existing member 1 and the reinforcing steel material 3 are fixed with the high-strength fiber sheet 4, the strength against peeling can be ensured regardless of whether the angle steel existing member 1 is coated or galvanized. Furthermore, by applying an adhesive also between the high strength fiber sheets 4 wound around the outer surface of the angle steel existing member 1 and the outer surface of the reinforcing steel material 3 more than twice, the reinforcing steel material 3 is applied to the angle steel existing member 1. It can fix reliably and can improve the buckling proof stress of the existing angle steel member 1. Moreover, since the reinforcing steel member 3 is attached to the existing angle member 1 to stiffen it against buckling, even if the stress sharing to the reinforcing steel member 3 is small, the proof strength of the existing angle member 1 is increased. I can expect.

  In addition, although the above demonstrated the case where it applied to the steel tower, it is not restricted to this, This invention is applicable also to reinforcement of the steel structure member of another truss structure.

It shows one embodiment of the reinforcing method of the present invention, (a) is a side view of a reinforced steel structural member, (b) is a side view of the reinforced steel material, (c) is a perspective view of the reinforced steel material, (D) is a horizontal sectional view of (a), (e) is a horizontal sectional view of (b), and (f) and (g) are horizontal sectional views when the shapes of the reinforcing steel materials are different. It is a horizontal sectional view of a steel structure member, (a) is a conventional reinforcement method, (b) is a step bolt, (c), (d) is a case of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Existing part of angle steel 1a ... Flange 2 ... Gusset plate 3 ... Reinforced steel (attachment)
4 ... High-strength fiber sheet 5 ... Stiffener plate

Claims (5)

It is a method for reinforcing open-section steel such as angle steel, which is a steel structural member of a truss structure,
Reinforced steel as an auxiliary material is attached to the open cross-section steel so that a pair of open ends of the open cross-section steel is closed to form a closed cross section, and a high-strength fiber sheet is attached to the outer surface of the open cross-section steel and the outer surface of the reinforcing steel. A method for reinforcing a steel structural member, comprising fixing an open-section steel material and a reinforcing steel material by winding in a circumferential direction while bonding.   The method for reinforcing a steel structural member according to claim 1, wherein the high strength fiber sheet is wound more than twice around the outer surface of the open section steel material and the outer surface of the reinforcing steel material, and the adhesive is also provided between the wound high strength fiber sheets. A method for reinforcing a steel structural member, wherein   3. A method for reinforcing a steel structural member according to claim 1 or 2, wherein a closed cross section having a square cross section is formed by the open section steel material of the angle iron and the reinforcing steel material of the angle steel. Method.   The method for reinforcing a steel structure member according to claim 1 or 2, wherein a closed cross section having a triangular cross section is formed by the open section steel material of the angle iron and the reinforcing steel material of the steel plate. .   5. The method for reinforcing a steel structural member according to claim 1, wherein a stiffening plate material orthogonal to the material axis is attached to the inside of the reinforcing steel material at a predetermined interval in the material axis direction. A method for reinforcing a steel structural member, wherein:

Images