JP2007040052A - Steel for unbonded prestressed concrete, its manufacturing method and structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide unbonded steel for prestressed concrete additionally having a simple antiseismic damping function, and an unbonded prestressed concrete structure using the unbonded steel for prestressed concrete. <P>SOLUTION: Steel 2 for prestressed concrete is placed in a sheath 1. A viscous antirust 4 is filled in a gap 3 between the sheath 1 and the steel 2 for the prestressed concrete. A winding sheath, polyethylene sheath or the like having a high adhesion is used for the sheath 1. PC steel rods, PC stranded wires, or deformed PC steel rods, high-strength steel bars or the like are used for the steel 2 for the prestressed concrete. The antirust 4 having a viscosity is also used. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an unbonded PC steel material having a function as a simple damping damper, a method for producing the PC steel material, and an unbonded prestress structure using the unbonded PC steel material.

  In general, unbonded PC steel is placed in members such as columns, beams, slabs, etc., such as PC structures, PRC structures, RC structures, and SRC structures, and is tensioned after the concrete is hardened to give compressive force (prestress) to the concrete. Therefore, it is often used to construct a long span frame that does not generate bending cracks even under long-term loads.

  In the unbonded prestress structure, grouting after tensioning of the PC steel material is not performed, and therefore, a corrosion preventive agent such as asphalt is previously applied to the surface of the PC steel material.

  The rust preventive agent in this case includes (1) that the PC steel material can follow the elongation of the PC steel material at the time of tension, does not generate adhesion resistance and friction resistance, and the stress distribution of the PC steel material becomes constant, (2 ) The deterioration of the rust preventive agent itself to a certain degree of temperature change over a long period of time, (3) In addition, it does not have a chemical adverse effect on concrete, PC steel, sheath tube, (4) Long rust preventive agent It is required to have properties such as that the PC steel material does not rust because it has a waterproof property and water barrier property for a period.

  For this reason, in the conventional unbonded prestressed structure, emphasis is placed on the fact that the PC steel material has sufficient waterproof / rustproof performance for a long period of time and that the rust inhibitor can sufficiently follow the PC steel material when the PC steel material is in tension. It was.

JP 2004-169363 A Japanese Patent Laid-Open No. 11-172761 JP 2001-90253 A Japanese Patent Laid-Open No. 2002-4418

  However, according to previous studies conducted by the present applicant, the unbonded PC steel material, which is a combination of a high-viscosity rust preventive agent (hereinafter referred to as “viscous rust preventive agent”), and a PC steel material having a large surface profile. -It was found that when dynamic deformation was generated between the viscous rust preventive agent, energy consumption occurred due to the frictional resistance and adhesion resistance between the PC steel material and the viscous rust preventive agent, resulting in additional attenuation.

  It was also confirmed that even when unbonded PC steel with large additional damping was used, the stress distribution of the PC steel was constant when the PC steel was in tension, and partial stress concentration during the tension was avoided.

  In other words, it was found that the unbonded PC steel material itself has a function as a simple vibration control damper by devising the material constituting the unbonded PC steel material.

  However, there have been few studies on the use of unbonded PC steel as a damping damper, and it was unknown whether there is a combination that actually has sufficient energy consumption.

  In view of these problems, the present invention has been made with a focus on the development of an additional damping unbonded PC steel material. The unbonded PC steel material also has a function as a simple damping damper, a method for producing the unbonded PC steel material, and the unbonded PC material. An object of the present invention is to provide an unbonded prestressed structure using steel.

  The unbonded PC steel material according to claim 1 is installed in a sheath, a PC steel material installed in the sheath, and a gap between the PC steel material and the sheath, and is attenuated by friction resistance or adhesion resistance with the PC steel material. It is comprised from the viscous rust preventive agent which adds.

  The present invention expects energy consumption due to the frictional resistance and adhesion resistance between the PC steel material and the viscous rust preventive agent accompanying the deformation between the PC steel material and the viscous rust preventive agent.

  For example, when unbonded PC steel is used for structural members such as pillars and beams in building structures and civil engineering structures, when PC steel expands and contracts due to dynamic loading such as wind, earthquake, and traffic vibration, Deformation occurs between viscous rust inhibitors, and energy such as wind and earthquake is consumed.

  That is, in this case, the unbonded PC steel can be said to be a member that not only functions as a structural member that transmits stress but also functions as a vibration control damper that consumes wind, seismic energy, and the like.

  In conventional unbonded PC steel, a material with low friction resistance was used, so even if deformation occurred between the PC steel and the rust inhibitor, energy consumption could not be expected. In the unbonded PC steel material of the present invention using a rusting agent, an optimal PC steel material and a sheath, when deformation occurs between the PC steel material and the viscous rust inhibitor, energy is generated by friction resistance and adhesion resistance between the PC steel material and the viscous rust inhibitor. Consumption occurs.

  The present applicant pays attention to the energy consumption of such unbonded PC steel, and in order to examine the optimal combination of unbonded PC steel, he conducted a full-scale dynamic adhesion experiment of unbonded PC steel, Verified.

  8 (a) to 8 (d) show the experimental results, (a) shows a case where a viscous rust inhibitor having a high viscosity and a deformed PC steel material are combined, and (b) shows a viscous rust inhibitor and a variant having a low viscosity. When PC steel is combined, (c) is a combination of a slightly higher viscosity viscous rust inhibitor and a deformed PC steel, and (d) is a combination of a slightly higher viscosity viscous rust inhibitor and PC round steel. Each case is shown.

  From this experimental result, it was found that an unbonded PC steel material having a large energy consumption is formed when a viscous rust inhibitor having a high viscosity is combined with a large PC steel material having a rough surface. Moreover, it turned out that the energy consumption of unbonded PC steel material is largely dependent on the kind of viscous rust preventive agent rather than the kind of PC steel material.

  Furthermore, use PC steel material with high strength and high adhesion and unbonded PC steel material using viscous rust preventive with excellent properties such as high fluidity, no shrinkage, high strength, high adhesion and high rust prevention. As a result, not only can corrosion of PC steel be prevented, but also energy consumption due to frictional resistance and adhesion resistance between PC steel and viscous rust inhibitor can be expected. When used as a simple damping damper, wind, earthquake, traffic vibration, etc. It has been found that it has beneficial effects such as securing adhesion damping against external force due to dynamic loading of the.

  In addition, when high addition damping is expected, the combination of the PC steel material and the viscous rust inhibitor may be selected with the largest energy consumption ability due to the frictional resistance and adhesion resistance between the PC steel material and the viscous rust inhibitor. It was also found that the additional attenuation can be controlled by a combination of the length of the PC steel material and the setting of the unbonded section.

  In this case, as the PC steel material, a PC steel bar (round steel), a PC steel strand, a deformed reinforcing bar, a deformed PC steel rod, a PC steel strand with indentation, etc., which are mainly used in the conventional PC structure are used. be able to.

  Viscous rust inhibitors include greases, waxes, epoxies, asphalts, rubbers, urethanes, silicones, oils, polyolefin polyols, liquid carbonization, which have high fluidity, no shrinkage, high adhesion, high viscosity, and rust resistance. Hydrogen resin various rubber blends, or other chemical substances or mixtures can be used.

  Furthermore, the sheath can be a wiping sheath having a high adhesion such as an uneven surface, a polystyrene sheath, a steel pipe, or a concrete mortar surface with an uneven surface.

  As a method of manufacturing the unbonded PC steel material of the present invention, after inserting the PC steel material into the sheath, a method of filling the gap between the sheath and the PC steel material with a high-viscosity rust inhibitor, the PC steel material in the sheath Before inserting, the method of inserting or winding the viscous rust preventive agent directly on the surface of the PC steel material in advance and then inserting the PC steel material into the sheath tube, or applying the viscous rust preventive agent directly on the surface of the PC steel material or For example, there is a method of winding and coating a polystyrene resin or the like which is cured and becomes a sheath thereon.

The unbonded PC steel material according to claim 2 is the unbonded PC steel material according to claim 1, wherein the viscosity of the viscous rust inhibitor is 0.001 MPa to 10 MPa, or the viscosity at 25 ° C. is 1.0 × 10 ³ Pa. Urethane, silicone, oil, polyolefin-based polyol, wax, liquid hydrocarbon resin, etc. with a viscosity of ˜1.0 × 10 ¹² Pa, rubber, grease with consistency (consistency) of 200 or less, epoxy with consistency of 400 or less, needle penetration It is a viscous rust preventive containing asphalt having a degree of 150 or less, or a mixture thereof.

  Here, the consistency is a test value of a consistency test for measuring the hardness of a material standardized by JISK2220. The consistency test is performed by intruding a specified cone into a sample and determining the penetration length. Represents the hardness of the sample. The penetration value is 1/10 mm, and the penetration value is 1. The larger the value, the softer the material, and the softer the material is, the softer the penetration test is used.

  The unbonded PC steel according to claim 3 is the unbonded PC steel according to claim 1 or 2, wherein the sheath is provided with irregularities.

  The unbonded PC steel material according to claim 4 is the unbonded PC steel material according to any one of claims 1 to 3, wherein the PC steel material is particularly limited to be provided with irregularities.

  The method for producing an unbonded PC steel according to claim 5 is characterized in that a viscous rust inhibitor is attached to the outer periphery of the PC steel, and then a sheath is placed on the viscous rust inhibitor.

  As a method of attaching the viscous rust preventive agent to the outer periphery of the PC steel material, for example, there is a method of forming the viscous rust preventive agent in a strip shape and winding it around the outer periphery of the PC steel material.

  In addition, as a method of covering the sheath on the viscous rust preventive agent, in addition to using a steel pipe as the sheath, a resin material that hardens after being applied to the surface of the viscous rust preventive agent and becomes a sheath is used. There is a method such as painting on.

  The method for producing an unbonded PC steel material according to claim 6 is the method for producing an unbonded PC steel material according to claim 5, in which unevenness is particularly provided on the outer periphery of the viscous rust inhibitor.

  8. The unbonded prestress structure according to claim 7, wherein the unbonded PC steel material is a sheath, a PC steel material installed in the sheath, and the PC steel material. And a viscous rust preventive agent that can be added with a damping property by friction resistance or adhesion resistance with the PC steel material.

  In particular, the present invention is applied to members such as pillars, beams, slabs, etc., such as PC structures, PRC structures, RC structures, SRC structures, etc. for building structures, civil engineering structures, etc. Long span that does not occur is possible, and seismic control of the structure can be achieved.

  According to the present invention, unbonded PC steel has good adhesion properties to PC steel, and is a deformed bar steel that can sufficiently handle tension, high strength rebar, PC steel strand, indented PC steel strand, PC Uses all types of PC steel or PC wire such as steel bars and deformed PC steel bars, and has excellent fluidity, non-shrinkage, high strength, high adhesion, and high rust prevention properties for viscous rust inhibitors. By using all kinds of viscous rust preventives such as wax, epoxy, asphalt, rubber, urethane, silicone, oil, polyolefin polyol, liquid hydrocarbon resin, various rubber blends or mixtures and compounds thereof, the viscosity of PC steel When relative displacement occurs between rust inhibitors, it also functions as a damping damper that can consume energy between PC steel and viscous rust inhibitor. It is possible to create an unbonded PC steel with.

  Further, the energy consumption capacity and the additional attenuation can be freely controlled by the combination of the unbonded PC steel material and the viscous rust inhibitor, the combination of the length of the PC steel material, the setting of the bond / unbond section, and the like.

  1 to 4 show an example of an unbonded PC steel material according to the present invention. In the figure, a PC steel material 2 is installed in a sheath 1, and a viscosity prevention is provided in a gap 3 between the sheath 1 and the PC steel material 2. Rust agent 4 is installed.

  As the sheath 1, for example, a wiping sheath or polyethylene sheath having a highly irregular surface and high adhesion as shown in FIGS. 1A and 1B is used.

  Further, for example, as shown in FIG. 1 (c), a sheath 1 for installing the PC steel material 2 may be formed by forming irregularities 5a on the inner periphery of a through hole 5 provided in a casing made of concrete or mortar. it can.

  Further, a viscous rust preventive agent 4 may be applied or wound around the outer periphery of the PC steel material 2, and a polyethylene resin or the like that will harden after application and become the sheath 1 may be applied thereon.

  For the PC steel material 2, for example, a PC steel rod 2a, a PC steel twisted wire 2b, and a deformed PC steel rod 2c as shown in FIGS. 2A, 2B, and 2C are used. For example, as shown in FIGS. 3 (a) to 3 (c), the stranded wire may be an indented PC steel wire having an indent (concave portion) 22e on the surface of the PC steel wire.

  The viscous rust inhibitor 4 is inserted into the sheath 1 after the PC steel material 2 is inserted into the gap 3 between the sheath 1 and the PC steel material 2 or before the PC steel material 2 is inserted into the sheath 1. In addition, it is installed between the sheath 1 and the PC steel material 2 so as to wrap a thing previously processed into a string shape around the outer periphery of the PC steel material 2.

  FIG. 4 shows a fixing portion at the end of the PC steel material 2, and the end of the PC steel material 2 is fixed by a supporting member 6 and a fixing member 7 such as a fixing nut.

  5 (a) and 5 (b) show an example of a method of attaching the viscous rust inhibitor 4 to the outer periphery of the PC steel material 2, while rotating the PC steel material 2 as shown in FIG. 5 (a). The viscous rust preventive agent 4 processed into a string shape is wound around the outer periphery of the PC steel material 2 in a spiral shape, and thereafter, the surface of the viscous rust preventive agent 4 is formed into an uneven shape by the processing machine 8.

  FIGS. 6 and 7 show a method of installing the unbonded PC steel material of the present invention at a joint between a column such as an RC structure and a beam.

  In the case of the method illustrated in FIGS. 6A to 6C, first, the unbonded PC steel material 9 having the above-described configuration, which has been manufactured in advance at a factory or the like, is composed of the pillar 10 and the beams on both sides thereof that have been arranged on site. 11 and 11 are set in a hanging curve shape.

  Next, the concrete of the pillar 10 and the beams 11 and 11 on both sides thereof is placed. Then, after the concrete is sufficiently cured, the PC steel material 2 is tensioned with the tensioning jack 12 to give post tension, and the end portion is fixed.

  In the case of the method illustrated in FIGS. 7A to 7D, the column 10 and the beams 11 on both sides thereof are used as a precast concrete (hereinafter referred to as “PCa”) member for the column and the beam, respectively. Produce. At that time, only the unbonded PC steel sheath 1 is embedded in the concrete of these PCa members in advance. Then, these PCa members are brought into the site and assembled.

  Next, the PC steel material 2 is continuously inserted through the column 10 and the sheath 1 of the both side beams 11 and 11, and the PC steel material 2 is tensioned by a tension jack 12 to give a predetermined post tension. After fixing, the pillar 10 and the beams 11 on both sides thereof are integrally joined. And the viscous rust preventive agent 4 is press-fitted into the gap between the sheath 1 and the PC steel material 2. The viscous filler 4 may be filled before tensioning the PC steel material.

  9, FIG. 10 and FIG. 11 show an example of an unbonded prestressed building using the unbonded PC steel material of the present invention, and each axial direction of each column 13, beam 14 and / or slab 15 in the concrete. A plurality of PC steel materials 9 having an unbonded structure are provided along the line.

  In addition, in the examples of FIGS. 9B, 9C and 10A, the PC steel material 9 installed on the upper end side of the beam 14 is installed in a suspended curve shape, and the example of FIG. The PC steel material 9 installed in the slab 15 is installed in a suspended curve shape.

Further, in the example of FIG. 10 (b), the out of PC steel 9 installed in the beam 14, a constant interval L ₁ of the joint and its one or both sides of the beam 14 of the beam 14 of each pillar 13 is unbonded structure without the interval L ₂ of the middle part of the beam 14 is in the beam 14 integral with structure (bond structure).

  Furthermore, in the example of FIG. 9C, FIG. 10A, and FIG. 10C, a plurality of unbonded PC steel materials 9 straddle between both members at the joints between the pillars 13 and the beams 14 as well. Among them, in the example of FIG. 9C and FIG. 10C, the PC steel material 9 is installed in a suspended curve shape. In addition, the joint mortar 23 is filled in the joint surface portion between each column 13 and the beam 14.

  In the example of FIG. 11B, a wall 16 is disposed between the beams 14 and 14 on the first floor and the second floor in the center of the building, and an unbonded PC steel material is provided between the wall 16 and the upper and lower beams 14 and 14. A plurality of 9 are installed.

  In the example of FIG. 11 (c), a plurality of cables 17 are installed radially from the upper end of the column 13 at the center of the building in the direction of girder on both sides, and the end of the cable 17 is an unbonded PC. Each is fixed to the foundation 24 through the steel material 9.

  FIG. 12A shows a cable-stayed bridge, and a plurality of cables 17 are obliquely projected from the upper end of each tower 18 between the bridge beams 18, and the leading end side of the cables 17 is passed through an unbonded PC steel material 9. Each is fixed to the digit 19.

  Moreover, FIG.12 (b) shows the roof of the stadium installed in the open space etc., and the PC steel material 9 of an unbond structure is used for the diagonal for installing the girder 20 diagonally in each tower 18. FIG.

13A and 13B show a concrete member manufactured as a sleeper or the like. In the example of FIG. 13A, a PC steel material 9 having an unbonded structure is provided in the concrete of the pretension member 21. is set up. In the example of FIG. 13B, the PC steel material 9 having an unbonded structure is installed in a certain section L ₃ in the middle portion of the post tension member 22.

  The present invention can be widely used not only as a structural member for transmitting stress in a building structure or a civil engineering structure, but also as a simple vibration control damper.

(A), (b), (c) is sectional drawing of the axial direction of an unbonded PC steel material. (A), (b), (c) is sectional drawing of the axis orthogonal direction of an unbonded PC steel material. (A) is a partial side view showing a strand of PC steel with indent, (b) is an end view thereof, and (c) is a partial side view showing a single strand of PC steel with indent. It is sectional drawing of the axial direction of the unbonded PC steel material edge part which shows the fixing | fixed part of PC steel material. (A) is a side view which shows the method of attaching a viscous rust preventive agent to the outer periphery of PC steel materials, (b) is sectional drawing of the axial direction which shows the method of attaching an unevenness | corrugation to the surface of a viscous rust preventive agent. (A)-(c) is a side view of the column-beam junction part which shows the installation method of unbonded PC steel materials. (A)-(d) is a side view of the column-beam junction part which shows the installation method of unbonded PC steel materials. (A)-(d) is a figure which shows the result of the full-scale dynamic adhesion experiment of unbonded PC steel materials. (A)-(c) is a front view which shows the building where the unbonded PC steel material was used. (A)-(c) is a front view which shows the building where the unbonded PC steel material was used. (A)-(c) is a front view which shows the building where the unbonded PC steel material was used. (A) is a front view which shows the cable-stayed bridge in which the unbonded PC steel material was used for the cable which hangs a bridge girder, (b) is a front view of a stadium. (A), (b) is sectional drawing of a post tension member and a pre tension member, respectively.

Explanation of symbols

1 Sheath 2 PC Steel 2a PC Steel Bar 2b PC Steel Strand 2c Modified PC Steel Bar 2d PC Steel Strand with Indent 2e Indent (concave)
DESCRIPTION OF SYMBOLS 3 Gap between sheath and PC steel material 4 Viscous rust preventive agent 5 Through hole 5a Concavity and convexity 6 Bearing member 7 Fixing tool 8 Processing machine 9 Unbonded PC steel materials 10, 13 Columns 11, 14 Beam 12 Jack for tension 15 Slab 16 Wall 17 Cable 18 Tower 19 Bridge girder 20 Girder 21 Pre-tension member 22 Post-tension member 23 Joint mortar 24 Foundation 25 Reinforcing bar

Claims (7)

  A sheath, a PC steel material installed in the sheath, and a viscous rust preventive agent that is installed in a gap between the PC steel material and the sheath and adds damping by frictional resistance or adhesion resistance with the PC steel material An unbonded PC steel characterized by that. Urethane, silicone, oil, polyolefin-based polyol having an adhesive stress degree of the viscous rust inhibitor of 0.001 MPa to 10 MPa, or a viscosity at 25 ° C. of 1.0 × 10 ³ Pa to 1.0 × 10 ¹² Pa, It is a viscous rust preventive containing wax, liquid hydrocarbon resin, rubber, grease having a consistency (consistency) of 200 or less, epoxy having a consistency of 400 or less, asphalt having a penetration of 150 or less, or a mixture thereof. The unbonded PC steel material according to claim 1.   The unbonded PC steel material according to claim 1 or 2, wherein the sheath is provided with irregularities.   The unbonded PC steel according to any one of claims 1 to 3, wherein the PC steel is provided with irregularities.   A method for producing an unbonded PC steel material comprising attaching a viscous rust preventive agent to the outer periphery of a PC steel material, and then covering the viscous rust preventive agent with a sheath.   6. The method for producing an unbonded PC steel material according to claim 5, wherein irregularities are provided on the outer periphery of the viscous rust inhibitor.   In an unbonded prestressed structure in which an unbonded PC steel is installed in a structure, the unbonded PC steel is installed in a sheath, a PC steel installed in the sheath, and a gap between the PC steel and the sheath, An unbonded prestress structure comprising a viscous rust inhibitor that adds damping by frictional resistance or adhesion resistance with PC steel.

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