JP5378922B2 - Fireproof coating structure of PC steel and its construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fire resistive covering structure excellent in fire resistance and heat resistance, and a method for constructing the same. <P>SOLUTION: This fire resistive covering structure includes rod-like prestressing steel 10 which has upper and lower ends connected to a structure 50 and which is obliquely arranged in a tensioned state, and an outside pipe 20 which is arranged in such a manner as to surround the peripheral surface of the prestressing steel 10 while having the gap between itself and the prestressing steel 10. A granular or powdery thermally-foamable fire-insulating material 30 is infilled in the gap between the prestressing steel 10 and the outside pipe 20. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a fireproof covering structure for PC steel used for construction, bridges, and the like, and a construction method thereof.

  Conventionally, steel materials used for structures and bridges are placed around the outer pipe so that there is a gap in the circumferential surface of the steel material in order to prevent the destruction of the steel material due to heat during a fire, and the mortar is placed in the gap between the steel material and the outer pipe. There is known a fireproof coating structure in which a grout material such as cement is filled and coated (see Patent Documents 1 and 2).

JP2007-46268 JP-A-10-183371

  However, the grout material has low fluidity due to the viscosity of the liquid and changes in viscosity depending on the moisture content. If the viscosity is low, it tends to sag and form voids and bubbles. There was a problem that bubbles and gaps were likely to remain.

  In addition, since the grout material is filled with the gravity of the grout material, the surface of the filled grout material becomes horizontal. There was a problem that an uncoated portion was generated.

  This invention is made | formed in view of the situation mentioned above, The objective is to provide the fireproof coating structure excellent in fire resistance and heat resistance, and its construction method.

  [1] An upper end and a lower end are connected to a structure, and are disposed so as to surround a peripheral surface of the PC steel material with a gap between the PC steel material and a rod-shaped PC steel material that is obliquely arranged in a tension state. A fire-resistant covering structure for PC steel, wherein a gap between the PC steel and the outer pipe is filled with a granular or powder heat-foaming fire-resistant heat insulating material.

  [2] The PC steel fireproof covering structure according to the item 1, wherein the PC steel material has a rust-proofing treatment on a peripheral surface.

  [3] The PC steel fireproof coating structure according to the above item 1 or 2, wherein the outer tube is divided into a plurality of portions in the longitudinal direction.

  [4] The PC steel fireproof coating structure according to any one of [1] to [3], wherein the outer pipe is divided into two in the axial direction.

[5] The outer tube is disposed so as to surround the peripheral surface of the PC steel while having a gap with the PC steel, and the upper end and the lower end are in tension in the structure so that the PC steel takes an oblique posture. connection,
A fire-resistant coating method for PC steel, wherein the gap is filled with a granular or powdery heat-foaming fire-resistant heat insulating material.

  [6] A structure built using the fireproof coating structure for PC steel according to any one of items 1 to 4.

  The present invention has the following effects.

  According to the invention of the preceding item [1], since it is filled with a granular or powdery heat-foamable refractory heat insulating material, due to the high fluidity of the solid, there is no gap or bubble, and no bubbles or gaps remain inside. In the case of a fire, the volume is increased by thermal foaming, so even if the exposed part remains on the side of the upper part of the PC steel facing obliquely upward, such an exposed part can be reliably covered, and as a result, A fire-resistant and heat-insulating structure excellent in fire resistance and heat resistance can be provided.

  According to the invention of [2], the PC steel material can be prevented from being deteriorated by rust because the peripheral surface of the PC steel material is subjected to the rust prevention treatment.

  According to the invention of [3], since the outer tube is divided into a plurality in the longitudinal direction, each outer tube can be filled with the heat-foaming refractory heat insulating material from between the outer tube adjacent to the upper side. Thereby, it can fill reliably from the near position where an unfilled part hardly remains with respect to each outer tube | pipe which becomes a filling part.

  According to the invention of the preceding item [4], since the outer pipe is divided into two in the axial direction, the outer pipe can be arranged after connecting the PC steel material without passing through the PC steel material in advance. Can be improved. Furthermore, the fireproof structure of the existing structure can be strengthened.

  According to the invention of the preceding item [5], the outer tube is disposed so as to surround the PC steel while having a gap with the PC steel, and the upper end and the lower end are arranged so that the PC steel takes an oblique posture. Because it is connected to the structure in tension and the gap is filled with granular or powdery heat-foaming refractory insulation, the high fluidity of the solids prevents voids and bubbles, leaving no bubbles or gaps. It is possible to cover up to an unfilled portion generated on the side surface of the upper portion of the steel material which is directed obliquely upward due to the increase in volume due to foaming by the heat of the heat, and the fire resistance and heat resistance can be improved.

  According to the invention of the preceding item [6], since it is a structure built by the fireproof covering structure described in any one of the preceding items 1 to 4, the above-described effects can be exhibited.

FIG. 1 is a front view showing a fireproof coating structure for PC steel according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a fireproof covering structure of the PC steel material. FIG. 2 is a process diagram showing a first process of the PC steel fireproof covering structure. FIG. 3 is a process diagram showing a second process of the fireproof covering structure of the PC steel material. FIG. 4 is a process diagram showing a third process of the fireproof covering structure of the PC steel material. FIG. 6: is an external appearance sectional view which shows the whole structure constructed | assembled through the 1st-3rd process using the PC steel material. FIG. 7 is a diagram showing a change in foaming of a heat-foamable fireproof heat insulating material. (A) illustrates a heat-foamable fireproof heat-insulating material before foaming and (B) after foaming. FIG. 8 is a cross-sectional view showing a PC steel fireproof coating structure according to a second embodiment of the present invention. FIG. 9: is sectional drawing which showed the fireproof coating structure of PC steel materials concerning 3rd Embodiment of this invention.

  Next, a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a front view showing a fireproof coating structure for PC steel according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a fireproof covering structure of the PC steel material.

  As shown in FIGS. 1 and 2, the fireproof coating structure 1 for PC steel according to the first embodiment includes a PC steel 10, an outer tube 20, a heat-foaming fireproof heat insulating material 30, and a rust-proof treatment part 40. And is composed of.

  “PC steel material 10” refers to a steel material used as a tension material for prestressed concrete. The PC steel material 10 includes a steel wire, a PC steel wire, a steel bar, and the like. The PC steel material 10 according to this embodiment is formed by twisting and bundling a plurality of (in this embodiment, seven) strands 10a. The diameter of the strand 10a is preferably, for example, 9.5 to 15.2 mm. In this embodiment, the diameter of 12.7 mm or 15.2 mm is adopted. The thickness of a plurality of (seven in this embodiment) PC steel material 10 is preferably 15.2 to 76.0 mm, for example, and is 38.1 mm or 45.6 mm in this embodiment.

  Fixing tools 14 are attached to the upper and lower ends of the PC steel material 10 so as to be connected to the structure 50 in a tensioned state. A screw groove 14a is formed in the fixture 14, and an anchor plate 15 is passed through the screw groove 14a, and a nut 16 is screwed. By rotating the nut 16, the anchor plate 15 moves in the longitudinal direction of the PC steel material 10. A protective cover 17 is attached to the peripheral surfaces of the nut 16 and the upper end of the fixing tool 14 in order to prevent deterioration of the screw groove 14a of the fixing tool 14, the nut 16, and the like. An end plug 19 is attached to the tip of the fixture 14.

  On the peripheral surface of the PC steel material 10, a rust prevention treatment portion 40 is formed. This rustproofing part 40 is formed by applying a rustproofing material.

  On the peripheral surface of the PC steel material 10, it arrange | positions so that the outer side pipe | tube 20 may have a predetermined clearance gap. This gap is preferably set to 3 to 50 mm, for example, and in this embodiment is set to 20 to 40 mm.

  The outer tube 20 is made of, for example, a steel tube formed in a circular cylindrical shape. The diameter of the outer tube 20 is preferably 40 to 240 mm, for example, and in this embodiment, a diameter of 90 to 130 mm is adopted.

  The length in the longitudinal direction of each outer tube 20... Is preferably, for example, 1000 to 5000 mm. In this embodiment, a length of 1500 mm is adopted.

  The outer tube 20 is divided into a plurality in the longitudinal direction, and the outer tubes 20 are arranged adjacent to each other. The adjacent outer pipes 20 are connected by, for example, an adhesive 21. The total length when all the adjacent outer pipes 20 are bonded 21 is set to have a certain interval when connected to the structure in order to secure a filling port of the heat-foamable refractory heat insulating material. Yes.

  A gap between the PC steel material 10 and the outer pipe 20 is filled with a granular or powdery heat-foaming refractory heat insulating material 30.

  Here, the term “granular” refers to a solid that is large enough to recognize its shape (grain shape) with the naked eye. Further, the “powder” refers to a solid that has a size such that its shape (grain shape) cannot be recognized with the naked eye. In the present invention, those having a particle size of 1 mm or more are called “granular”, and those having a particle size of less than 1 mm are called “powder”.

  The particle size of the granular or powdery heat-foamable refractory heat insulating material 30 is preferably, for example, 0.5 to 1.5 mm. In this embodiment, a granular particle of 1.0 mm is adopted.

  This heat-foamable refractory heat insulating material 30 has a property of foaming and expanding due to heat. The heat-foamable refractory heat insulating material 30 is preferably one that expands to about twice or more the diameter after foaming when subjected to heat, for example.

  Next, the construction sequence of the fireproof coating structure for PC steel according to this embodiment will be described.

  FIG. 3 is a process diagram showing a first process of the fireproof covering structure of the PC steel material. FIG. 4 is a process diagram showing a second process of the fireproof covering structure of the PC steel material. FIG. 5 is a process diagram showing a third process of the PC steel fireproof covering structure.

  First, materials necessary for construction and structures to be constructed will be described.

  As shown in FIGS. 3 to 5, the materials necessary for the work are PC steel material 10 subjected to rust prevention treatment (rust prevention treatment portion 40), and outer tube 20... Divided into a plurality in the longitudinal direction. The steel material drawing cable 12. The worker H carries these materials into a construction place (hanging position) in the structure 50.

  Next, the structure 50 to which the PC steel material 10 is attached will be described.

  Steel material insertion holes 51 for inserting the PC steel material 10 and fixing both ends thereof are formed in advance on the ceiling and floor 53 of the middle floor of the structure 50. The upper steel material insertion hole 51 is formed at the ceiling of the planned installation floor, that is, the location where the upper floor 53 and the column 52 intersect, and the lower steel material insertion hole 51 is the floor 53 of the planned installation floor, The steel material insertion hole 51 is formed at a position obliquely below. Further, the steel material insertion hole 51 is inclined along the oblique posture of the PC steel material 10 so that the PC steel material 10 arranged in the oblique posture is linear over the entire length. Further, the steel material insertion hole 51 is formed with an outer tube receiving portion 51 a having a slightly larger diameter than the outer tube 20 and an anchor plate receiving portion 51 b having a slightly larger diameter than the anchor plate 15.

  Next, the first step will be described.

  As shown in FIG. 3, the worker H attaches the PC steel material drawing cable 12 to the upper end portion of the PC steel material 10. And the worker H inserts the PC steel material 10 in the outer side pipes 20 ... divided into a plurality in the longitudinal direction. Then, the worker H inserts the PC steel material pulling cable 12 into the steel material insertion hole 51 on the upper side of the planned installation floor, and the worker H draws the PC steel material pulling cable 12 from the outside of the structure 50, and the PC steel material. 10 is inserted into the steel material insertion hole 51 and temporarily secured so that the upper end portion of the PC steel material 10 does not fall out of the steel material insertion hole 51.

  Next, the second step will be described.

  As shown in FIG. 4, first, the worker H passes the anchor plate 15 through the fixing member 14 of the PC steel material 10 inserted into the steel material insertion hole 51 on the lower side of the planned installation floor, and screw-fits the nut 16. Thus, the anchor plate 15 attached to the lower end portion of the PC steel material 10 is locked by the anchor plate receiving portion 51 b of the structure 50, whereby the lower end portion of the PC steel material 10 is fixed to the structure 50.

  Next, the worker H passes the anchor plate 15 through the fixture 14 of the PC steel material 10 inserted into the steel material insertion hole 51 on the upper side of the planned installation floor, and screws the nut 16 into the screw. At this time, by rotating the nut 16, the anchor plate 15 locked to the anchor plate receiving portion 51b moves downward, and the PC steel material 10 becomes in a tension state. This tension work can be performed using, for example, a tension jack. When the above tension work is completed, the worker H attaches the protective cover 17.

  The outer tube 20 stops at the outer tube receiving portion 51a and is not inserted into the outer tube 20 from the outer tube receiving portion 51a.

  Next, the third step will be described.

  As shown in FIG. 5, the worker H is in the gap between the PC steel material 10 and the outer pipe 20 from between the outer pipe 20 positioned on the lowermost side and the outer pipe 20 adjacent to the upper side (filling portion). The heat-foaming refractory heat insulating material 30 is sufficiently filled. When the heat-foamable refractory heat insulating material 30 is sufficiently filled in the gap, the worker H can connect the filling portion (the outer pipe 20 positioned on the lowermost side and the outer pipe 20 adjacent to the upper side with the filling section). Adhesive 21). Then, the worker H sufficiently fills the heat-foamable refractory heat insulating material 30 in the same manner from between the outer tube 20 that has already been bonded 21 and the outer tube 20 adjacent to the upper side thereof. Is bonded 21. This operation (filling operation and bonding operation) is repeated up to the outermost tube 20 on the uppermost side. In addition, about the outermost pipe 20 on the uppermost side, the worker H is filled with the heat-foamable refractory heat insulating material 30 from the space between the lower outer pipe 20 and the upper side.

  Next, the worker H finishes the upper end and the lower end of the PC steel material 10 already fixed to the structure 50 by backfilling 54 with non-shrinking mortar or the like to prevent deterioration.

  FIG. 6: is an external appearance sectional view which shows the whole structure constructed | assembled through the 1st-3rd process using the PC steel material. This structure 50 is a structure 50 having a suspended structure, and includes columns 52..., A floor 53..., And a PC steel material 10 provided with a fireproof coating. One PC steel material 10 is connected to each of the left and right pillars 52, 52. Moreover, the two PC steel materials 10 and 10 are connected to the center column 52 from right and left so that it may cross. The floor 53 is supported by the PC steel material 10 suspended from the upper floor. The PC steel material 10 used here is connected in a tension state as a suspension member that takes advantage of the characteristics of the PC steel material 10. Moreover, this structure 50 is a parking lot, for example.

  FIG. 7 is a diagram showing a change in foaming of the heat-foamable refractory heat insulating material 30. (A) illustrates the heat-foamable refractory heat insulating material before foaming and (B) after foaming.

  As shown in FIG. 7A, before foaming by receiving heat from a fire or the like, the surface of the heat-foaming refractory heat insulating material 30 becomes horizontal due to the influence of gravity, and the outer tube 20 disposed obliquely. A gap C (unfilled portion) is formed inside. That is, since an unfilled portion is formed before foaming, the side surface of the upper portion of the PC steel material 10 facing obliquely upward is exposed. At this time, the heat-foamable refractory heat insulating material 30 filled on the lower side of the PC steel material 10 is covered to every corner without any gaps or bubbles due to the high fluidity of the solid.

  As shown in FIG. 7B, after each granular heat-foaming refractory insulation 30 receives heat during a fire or the like, each thermal-foaming refractory insulation 30 expands and expands (this embodiment) Then, the volume of the heat-foamable refractory heat insulating material 30 is increased and the entire peripheral surface of the PC steel material 10 is refractory coated. At this time, the PC steel material 10 is covered also about the gap C (unfilled portion) that was not covered before foaming. That is, the exposed portion of the PC steel material 10 that existed before foaming is also fireproof coated.

  The fireproof covering structure for PC steel according to this embodiment has the following advantages.

  That is, since the fire-resistant covering structure 1 of PC steel is composed of the PC steel 10, the outer tube 20, the heat-foaming fire-resistant heat insulating material 30 and the rust-proofing portion 40, it flows down due to the high fluidity of the solid. In addition, there is no air bubbles or gaps left inside, and there is no air bubbles or gaps in the interior, and thermal foaming will increase the volume in the event of a fire, so even if exposed parts remain on the side facing diagonally upward above the steel material, Therefore, it is possible to provide a fireproof and heat insulating structure excellent in fire resistance and heat resistance.

Furthermore, because the heat-foamable refractory insulation 30 is heated and expands more than twice the diameter before foaming, the foam expands in the event of a fire and the volume increases. Even if the exposed portion remains on the side facing the surface, the exposed portion can be reliably covered, and as a result, a fire-resistant and heat-insulating structure excellent in fire resistance and heat resistance can be provided.
Furthermore, since the rust prevention processing part 40 was formed by apply | coating a rust prevention material to the surface of PC steel material 10, degradation by PC rust by rust can be prevented.

  Furthermore, since the outer pipe 20 is a steel pipe, a sufficient time can be ensured until the thermally foamable refractory heat insulating material expands by heat and covers the PC steel material 10.

  Furthermore, the worker H attaches the PC steel material drawing cable 12 to the upper end portion of the PC steel material 10, inserts the PC steel material 10 into the outer pipes 20 divided into a plurality in the longitudinal direction, and the worker H The PC steel material pulling cable 12 is inserted into the steel material insertion hole 51 on the upper side of the planned installation floor, the worker H pulls the PC steel material pulling cable 12 from the outside of the structure 50, and the PC steel material 10 is inserted into the steel material insertion hole 51. Since it was inserted, the PC steel material 10 can be easily inserted into the steel material insertion hole 51.

  Furthermore, the worker H passes the anchor plate 15 through the fixture 14 of the PC steel material 10 inserted into the steel material insertion hole 51 on the upper side of the planned installation floor, and the nut 16 is screwed. At this time, the worker H By using the tension jack to rotate the nut 16, the anchor plate 15 locked to the anchor plate receiving portion 51 b moves downward, and the PC steel material 10 becomes in a tension state. The PC steel material 10 can be connected to the structure 50 in a tensioned state.

  Furthermore, the worker H has a heat-foaming refractory fire between the outer pipe 20 located on the lowermost side and the outer pipe 20 adjacent to the upper side (filling portion) in the gap between the PC steel material 10 and the outer pipe 20. When the heat insulating material 30 is sufficiently filled, and the heat-foamable refractory heat insulating material 30 is sufficiently filled in the gap, the worker H fills the filling portion (the outer pipe 20 positioned on the lowermost side and the upper side thereof). Between the outer tube 20 already bonded 21 and the outer tube 20 adjacent to the upper side of the outer tube 20 in the same manner. Filling and adhering the filling part 21 in the same manner, and this operation (filling operation and adhering operation) was repeated up to the outermost tube 20 on the uppermost side. The heat-foaming refractory insulation 30 can be filled from between the pipe 20 and , Can be reliably filled from a position near the unfilled portion is less likely to remain on each outer tube 20, ... as a filling part. In addition, due to the high fluidity of the solid, there are no voids or bubbles created by sagging, no bubbles or gaps remain in the interior, and thermal foaming in the event of a fire increases the volume. Even if the exposed portion remains at the time of filling, such an exposed portion can be reliably covered, and as a result, a fireproof and heat insulating structure excellent in fire resistance and heat resistance can be provided.

  Further, since the structure 50 is a suspended structure 50 composed of the pillars 52..., The floor 53... And the PC steel material 10 with the fireproof coating, the suspended structure 50. The effect mentioned above can be produced.

  Furthermore, since the structure 50 is a parking lot, the above-described effects can be achieved for this parking lot.

  Next, a second embodiment of the present invention will be described below with reference to FIG.

  FIG. 8 is a cross-sectional view showing a PC steel fireproof coating structure according to a second embodiment of the present invention.

  As shown in FIG. 8, the fireproof coating structure 2 of the PC steel material 10 according to the second embodiment includes a PC steel material 10, a heat-foamable fireproof heat insulating material 30, a rust prevention treatment portion 40, and outer tubes 60a and 60b. And bolt fastenings 70, 70. The outer tubes 60a and 60b are formed in a split shape in the axial direction and are divided into a plurality of portions in the longitudinal direction. The outer tubes 60a, 60b,... Are fixed by bolts 70, 70,. In addition, the PC steel material 10, the rust prevention treatment part 40, and the heat-foamable fireproof heat insulating material 30 are the same as those in the first embodiment.

  Next, the construction sequence of the fireproof coating structure for PC steel according to this embodiment will be described.

  The worker H connects the upper end and the lower end to the structure 50 in a tensioned state so that the PC steel material 10 takes an oblique posture. In this PC steel material 10, the worker H arranges one outer pipe 60 a divided in the axial direction so as to surround one circumferential surface of the PC steel material 10. It arrange | positions so that the other outer side pipe | tube 60b corresponding to it may be enclosed by the single-sided peripheral surface of PC steel material 10 of a corresponding side. These are fixed with, for example, bolts 70 and 70 to form cylindrical outer tubes 60a and 60b.

  This operation is repeated in the same manner, and a plurality of outer tubes 60a, 60b,... Divided in the longitudinal direction are arranged in the axial direction as in the first embodiment. Other steps are the same as those in the first embodiment.

  The fireproof covering structure for PC steel of the second embodiment has the following advantages.

  That is, the fireproof covering structure 2 of the PC steel material 10 is composed of the PC steel material 10, the thermally foamable fireproof heat insulating material 30, the rust-proofing portion 40, the outer tubes 60a and 60b, and the bolts 70 and 70, and the outer tubes 60a and 60b. Is divided into a plurality of parts in the longitudinal direction, and the outer tubes 60a, 60b,... Are fixed by bolting 70, 70,. Even if it is not passed through the PC steel material 10 in advance, the outer tubes 60a, 60b,... Can be arranged after the PC steel material 10 is connected, thereby improving workability.

  Furthermore, in the PC steel material 10 in which the upper end and the lower end are connected to the structure 50 in a tensioned state so that the PC steel material 10 takes an oblique posture, the worker H has one outer pipe 60a divided in two in the axial direction. It arrange | positions so that the single-sided peripheral surface of PC steel material 10 may be enclosed, and the other outer pipe | tube 60b corresponding to it is arrange | positioned so that it may surround the single-sided peripheral surface of PC steel material 10 of a corresponding side, and they are bolted 70,70, for example. To form cylindrical outer tubes 60a, 60b, and this operation is repeated in the same manner. As in the first embodiment, the outer tubes 60a, 60b,. Since the other steps are the same as those in the first embodiment, the outer pipes 60a, 60b,... 60a, 60b ・- it can be placed, which makes it possible to improve the workability.

  Next, a third embodiment of the present invention will be described below with reference to FIG.

  FIG. 9: is sectional drawing which showed the fireproof coating structure of PC steel materials concerning 3rd Embodiment of this invention.

  As shown in FIG. 9, the fireproof covering structure 3 of the PC steel material 10 according to the third embodiment includes the PC steel material 10, the rust prevention treatment part 40, the inner tube 80, the thermally foamable fireproof heat insulating material 30, And an outer tube 90.

  An inner pipe 80 is disposed on the peripheral surface of the PC steel material 10 with a predetermined gap. The clearance between the PC steel material 10 and the inner tube 80 is preferably set to 3 to 15 mm, for example, and in this embodiment, set to 5 to 8 mm. The inner tube 80 preferably has a diameter of, for example, 23 to 100 mm. In this embodiment, a diameter of 48 to 62 mm is employed. The inner tube 80 is made of, for example, hard polyvinyl chloride.

  An outer tube 90 is arranged on the peripheral surface of the inner tube 80 with a predetermined gap. The gap between the inner tube 80 and the outer tube 90 is set to have a width of 20 to 50 mm or more. For example, it may be set to 30 mm. This gap is filled with a heat-foaming refractory heat insulating material 30. The diameter of the outer tube 90 is preferably set to 65 to 200 mm, for example, and in this embodiment, a diameter of 130 to 160 mm is adopted. The outer tube 90 is made of, for example, hard polyvinyl chloride. Moreover, you may employ | adopt what is formed with the steel pipe etc. besides this. In addition, the other PC steel material 10, the antirust process part 40, and the heat-foaming fireproof heat insulating material 30 are the same as that of the said 1st Embodiment.

  The fireproof covering structure for PC steel according to the third embodiment has the following advantages.

  That is, since the fire-resistant covering structure of the PC steel material 10 is composed of the PC steel material 10, the rust-proofing portion 40, the inner tube 80, the heat-foaming fire-resistant heat insulating material 30 and the outer tube 90, the outer tube 90 and the heat-foaming fire-resistant heat insulating material. By forming the three-stage fireproof layer of 30 and the inner pipe 80, the time until the thermally foamable fireproof heat insulating material 30 expands by the heat at the time of the fire and covers the entire peripheral surface of the PC steel material 10 is increased. It is possible to provide a fireproof covering structure that can be surely secured and is more excellent in fire resistance.

  Further, since the inner tube 80 is disposed in the PC steel material 10 with a predetermined gap on the peripheral surface, the heat-foaming fireproof heat insulating material 30 does not directly contact the PC steel material 10, so the PC steel material by the heat-foamable fireproof heat insulating material 30. 10 deterioration can be prevented.

  As mentioned above, although this invention has been demonstrated based on 1st-3rd embodiment, this invention is not limited to this, You may comprise as follows.

  (1) In the said 1st Embodiment, although it was set as the granular heat-foaming fireproof heat insulating material 30, even if this invention is not limited to this and uses a powdery heat-foamable fireproof heat insulating material 30, it is. good.

  (2) In the first embodiment, for example, the heat-foamable refractory heat insulating material 30 that expands to about twice or more the diameter before foaming is used. However, the present invention is limited to this. It may be expanded several times as long as the volume is increased before foaming and after foaming.

  (3) In the said 1st Embodiment, although the rust preventive material was apply | coated to the PC steel material 10 (rust prevention process part 40), this invention is not limited to this, It does not necessarily apply | coat a rust preventive material (rust prevention). There is no need for the processing unit 40).

  (4) In the first embodiment, in the third step, the worker H is a PC steel material between the outer pipe 20 located on the lowermost side and the outer pipe 20 adjacent to the upper side (filling portion). When the thermal foamable refractory insulation 30 is sufficiently filled in the gap between the outer tube 20 and the outer pipe 20, and the thermal foamable refractory insulation 30 is sufficiently filled in the gap, the worker H can fill the filling portion (the most Between the outer tube 20 positioned on the lower side and the outer tube 20 adjacent to the upper side thereof) 21 and between the outer tube 20 already bonded 21 and the outer tube 20 adjacent to the upper side thereof Similarly, the heat-foamable refractory heat insulating material 30 is sufficiently filled, and the filling portion is similarly bonded 21. This operation (filling operation and bonding operation) is repeated up to the outermost tube 20 on the uppermost side. It is not limited to this, but first, the outer tube 20 adjacent to the uppermost outer tube 20 Then, all the outer pipes 20 and the adjacent outer pipes 20 are bonded 21, and thereafter, the thermal foaming refractory insulation 30 is filled from between the uppermost outer pipe 20 and the adjacent outer pipe 20 (filling portion). Then, the filling portion may be bonded 21.

  (5) In the first embodiment, the structure 50 is, for example, a parking lot. However, the present invention is not limited to this. For example, the structure 50 is used for an external cable such as a bridge or a building structure. You may use the PC steel material which gave the fireproof coating structure of this invention to the thing.

  (6) In the first embodiment, for example, the outer tube 20 is a steel tube formed in a circular cylindrical shape, but the present invention is not limited to this, and is not necessarily a circular cylindrical shape. For example, a cylindrical shape such as a square shape, a rectangular shape, or a triangular shape may be used. Further, the outer pipe 20 is not necessarily a steel pipe, and may be, for example, a hard polyvinyl chloride pipe or a finishing material used in construction or the like.

  The outer tube 20 does not necessarily have an excellent fire resistance, and has a fire resistance until the filled heat-foamable fire-resistant heat insulating material 30 is thermally foamed and covers the PC steel material 10 in a fire. It should be.

  (7) In the said 1st Embodiment, the fixing tool 14 for connecting to the structure 50 in a tension | tensile_strength state is fixed to the upper end and lower end of PC steel material 10, and the thread groove 14a is attached to this fixing tool 14. FIG. An anchor plate 15 is passed through the thread groove 14a and a nut 16 is screwed. The anchor plate 15 is moved in the longitudinal direction of the PC steel 10 by rotating the nut 16. A protective cover 17 is attached to the peripheral surfaces of the nut 16 and the upper end of the fixture 14 in order to prevent the thread groove 14a of the fixture 14 and the nut 16 from deteriorating. Although the part plug 19 is attached, the present invention is not limited to this, as long as the PC steel material to which the fireproof coating is applied can be connected to the structure 50 in a tension state. Need not be formed.

  (8) In the first embodiment, the outer tube receiving portion 51a is formed to have a slightly larger diameter than the outer tube 20, and the anchor plate receiving portion 51b is formed to have a slightly larger diameter than the anchor plate 15. The invention is not limited to this, and may have a diameter larger than that of the outer tube 20 and the anchor plate 15, and is not necessarily formed in this way.

  (9) In the second embodiment, the outer tubes 60a and 60b are fixed by, for example, bolt tightening 70 and 70. However, the present invention is not limited to this, and for example, the outer tube 60a formed in two in the axial direction. , 60b may be fixed by adhesive, welding, other coupling means, or the like.

DESCRIPTION OF SYMBOLS 10 PC steel material 20 Outer pipe | tube 30 Thermal foaming fireproof heat insulating material 40 Rust prevention process part 50 Structure 60a Outer pipe | tube 60b Outer pipe | tube 90 Outer pipe | tube

Claims (6)

A bar-shaped PC steel material whose upper end and lower end are connected to the structure and arranged obliquely in a tension state;
An outer pipe disposed surrounding the peripheral surface of the PC steel while having a gap with the PC steel,
A fireproof covering structure for PC steel, wherein a gap between the PC steel and the outer tube is filled with a granular or powdery heat-foaming fireproof heat insulating material.   The refractory coating structure for PC steel according to claim 1, wherein the PC steel has a rust-proofing treatment on a peripheral surface.   The said outer pipe | tube is divided | segmented into plurality in the longitudinal direction, The fireproof covering structure of PC steel materials of Claim 1 or 2 characterized by the above-mentioned.   The fireproof covering structure for PC steel according to any one of claims 1 to 3, wherein the outer pipe is divided into two in the axial direction. An outer tube is disposed surrounding the peripheral surface of the PC steel while having a gap with the PC steel,
The upper end and the lower end are connected to the structure in a tension state so that the PC steel takes an oblique posture,
A fire-resistant coating method for PC steel, wherein the gap is filled with a granular or powdery heat-foaming fire-resistant heat insulating material.   The structure built using the fireproof covering structure of PC steel materials of any one of Claims 1-4.

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