JP7186600B2 - Fixing structure between main girder and precast floor slab and fixing method between main girder and precast floor slab - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fixing structure for a main girder and a precast floor slab and a fixing method for the main girder and a precast floor slab.

A road bridge comprising a main girder having upwardly protruding studs, a precast floor slab having stud holes such as box vents for accommodating the studs, and a filler such as mortar for filling the box vents for accommodating the studs. A fixed structure between the main girder and the precast floor slab has been proposed. For example, in Patent Document 1, a precast floor slab formed with a plurality of stud holes for accommodating studs and combining with the steel girder is installed on the steel girder, and the steel girder is placed in the stud hole of the installed precast floor slab. A method is disclosed in which a stud is erected on the upper surface of the hole and the inside of the stud hole is filled with a filler.

Japanese Unexamined Patent Application Publication No. 2018-21403

By the way, there is a possibility that the interface between the precast floor slab and the filler may open on the upper surface of the precast floor slab due to the shrinkage of the filler such as mortar. If the boundary surface opens on the upper surface of the precast floor slab, moisture and salt will enter the lower surface of the precast floor slab due to rainwater, etc., which may reduce the durability of the fixed structure between the main girder and the precast floor slab. have a nature.

Accordingly, it is an object of the present invention to provide a fixing structure for a main girder and a precast floor slab and a method for fixing the main girder and a precast floor slab that can improve the durability of the structure for fixing the main girder and the precast floor slab. aim.

The present invention comprises a main girder having an upward projecting portion, a precast floor slab having an accommodating portion for accommodating the projecting portion on the lower surface, and a filler for filling the accommodating portion accommodating the projecting portion. Main girders and precast floor slabs where the length of the path from the upper surface of the slab to the lower surface of the precast floor slab along the interface between the housing part and the filler is longer than the distance between the upper and lower surfaces of the precast floor slab. is a fixed structure.

According to this configuration, there are provided a main girder having a projecting portion that projects upward, a precast floor slab having an accommodating portion that accommodates the projecting portion on the lower surface, and a filler that fills the accommodating portion that accommodates the projecting portion. In the fixed structure of the main girder and the precast slab, the length of the path from the upper surface of the precast slab to the lower surface of the precast slab along the interface between the housing section and the filler is Since it is longer than the distance from the bottom surface, the path for moisture and salt intrusion due to rainwater, etc. from the top surface of the precast floor slab to the bottom surface is longer than the thickness of the precast floor slab, and the durability of the fixed structure between the main girder and the precast floor slab. can improve sexuality.

In this case, it is preferable that the direction in which the boundary surface between the accommodating portion and the filler extends from the upper surface to the lower surface of the precast floor slab varies.

According to this configuration, since the direction in which the boundary surface between the container and the filler extends from the top surface to the bottom surface of the precast floor slab varies, the boundary surface extends from the top surface to the bottom surface of the precast floor slab. Compared to the case where the direction of movement does not change, the length of the path from the upper surface of the precast slab to the lower surface of the precast slab along the interface between the container and the filler becomes longer. The length of the route for moisture and salt to enter the lower surface due to rainwater and the like is lengthened, and the durability of the fixing structure between the main girder and the precast floor slab can be improved.

Further, the storage section may be open to the lower surface of the precast floor slab and closed to the upper surface of the precast floor slab.

According to this configuration, since the storage section is open to the lower surface of the precast floor slab and closed to the upper surface of the precast floor slab, the boundary surface between the storage section and the filler can be seen from the upper surface of the precast floor slab. Since there is no route to the lower surface of the precast floor slab along the slab, there is no route for water or salt to enter from the upper surface of the precast floor slab to the lower surface due to rainwater, etc., and the fixed structure of the main girder and the precast floor slab. durability can be improved.

Also, the storage section may be open to the lower surface and upper surface of the precast floor slab.

According to this configuration, since the storage section is open to the lower surface and upper surface of the precast floor slab, the filler can be injected from the upper surface of the precast floor slab, and the filler can be injected from the lower surface of the precast floor slab. Even when injecting the filler, it is easy to inject the filler because the air is easily released from the accommodating portion.

In this case, the boundary surface between the container and the filling material should include an inclined surface that is inclined so that the distance from the upper surface becomes shorter as it approaches the opening of the container that is open to the upper surface of the precast floor slab. is preferred.

According to this configuration, the boundary surface between the storage section and the filler is an inclined surface that is inclined so that the distance from the upper surface becomes shorter as it approaches the opening of the storage section that is open to the upper surface of the precast floor slab. Therefore, when the filling material is injected, air is easily released from the opening, and air is less likely to accumulate in the housing.

Moreover, it is preferable to further include a lid member that is larger than the opening area of the opening of the storage section that is open to the upper surface of the precast floor slab and covers the opening.

According to this configuration, since the lid member covering the opening of the storage section, which is open to the upper surface of the precast floor slab, is larger than the opening area and covers the opening, the precast floor can be viewed from the upper surface of the precast floor slab. The length of the path leading to the lower surface of the precast floor slab along the boundary surface between the upper surface of the slab and the lid member and the boundary surface between the container and the filler becomes longer, and the path from the upper surface to the lower surface of the precast floor slab becomes longer. The penetration path of moisture and salt due to rainwater, etc. is also lengthened, and the durability of the fixing structure between the main girder and the precast floor slab can be improved.

In this case, the lid member may be made of precast concrete.

According to this configuration, since the lid member is made of precast concrete, the quality of the lid member is not affected by the weather at the construction site. Moreover, installation of the lid member is easy.

Moreover, the lid member may be formed of cast-in-place concrete.

According to this configuration, since the cover member is made of cast-in-place concrete, it is difficult for a gap to occur at the interface between the upper surface of the precast floor slab and the cover member. It is possible to more effectively prevent the intrusion of moisture and salt due to

Moreover, it is preferable that the lid member is made of ultra-high-strength fiber-reinforced concrete.

According to this configuration, the lid member is made of ultra-high-strength fiber-reinforced concrete, so that the strength and durability of the lid member can be improved.

Further, the present invention includes a floor slab installation step of installing the precast floor slab on the main girder in a state in which the projecting portion projecting upward from the main girder is accommodated in the accommodation portion on the lower surface of the precast floor slab; a filling step of filling the filled storage portion with a filler, and in the floor slab installation step, the length of the path from the upper surface of the precast floor slab to the lower surface of the precast floor slab along the boundary surface between the storage portion and the filler; Saga is a method of fixing a main girder and a precast floor slab in which a precast floor slab that is longer than the distance between the upper surface and the lower surface of the precast floor slab is installed on the main girder.

In this case, in the floor slab installation step, it is preferable to install precast floor slabs on the main girders, the direction of which extends from the upper surface to the lower surface of the precast floor slab at the interface between the storage section and the filler material. be.

Further, in the floor slab installation step, the precast floor slabs may be installed on the main girders in which the storage section is open to the lower surface of the precast floor slab and closed to the upper surface of the precast floor slab.

Further, in the floor slab installation step, a precast floor slab in which the storage section is open to the lower surface and the upper surface of the precast floor slab may be installed on the main girder.

In this case, in the floor slab installation process, the boundary surface between the storage part and the filler was inclined so that the distance from the upper surface of the precast floor slab became shorter as it approached the opening of the storage part opened to the upper surface of the precast floor slab. It is preferable to install a precast deck slab containing a slope on the main girder.

In addition, before the filling material to be filled in the filling process solidifies, a lid having a larger opening area than the opening of the storage part opened to the upper surface of the precast floor slab installed on the main girder in the floor slab installation process It is preferable to further include a lid member installation step of installing the lid member so as to cover the opening with the member.

According to this configuration, in the lid member installation process, the opening area of the opening of the storage section that is open to the upper surface of the precast floor slab installed on the main girder in the floor slab installation process is larger than the opening area of the opening. Since the covering lid member is arranged, the route for moisture and salt to enter from the upper surface to the lower surface of the precast floor slab becomes longer, and the durability of the fixing structure between the main girder and the precast floor slab can be improved. . In addition, since the lid member installation step is performed before the filler to be filled in the filling step is solidified, it is possible to reduce moisture dissipation from the filler into the air and reduce drying shrinkage of the filler.

In this case, the lid member installed in the lid member installation step may be made of precast concrete.

Moreover, the lid member installed in the lid member installation step may be formed of cast-in-place concrete.

Moreover, it is preferable that the lid member installed in the lid member installation step is formed of ultra-high-strength fiber-reinforced concrete.

According to the fixing structure of the main girder and the precast floor slab and the fixing method of the main girder and the precast floor slab of the present invention, the durability of the fixing structure of the main girder and the precast floor slab can be improved.

Fig. 2 is a perspective view showing a fixing structure between a main girder and a precast floor slab according to the first embodiment; Fig. 4 is a perspective view of the vicinity of a projecting portion of the fixing structure between the main girder and the precast floor slab according to the first embodiment; Fig. 4 is a vertical cross-sectional view of the vicinity of the projecting portion of the fixing structure between the main girder and the precast floor slab according to the first embodiment; FIG. 4 is a vertical cross-sectional view showing a state after a floor slab installation process of the method of fixing the main girder and the precast floor slab according to the first embodiment. It is a longitudinal cross-sectional view of the vicinity of the projecting portion of the fixing structure between the main girder and the precast floor slab according to the second embodiment. It is a longitudinal cross-sectional view near the projecting portion of the fixing structure between the main girder and the precast floor slab according to the third embodiment. FIG. 11 is a vertical cross-sectional view of the vicinity of a projecting portion of a fixing structure between a main girder and a precast floor slab according to a fourth embodiment; FIG. 11 is a vertical cross-sectional view of the vicinity of a projecting portion of a fixing structure between a main girder and a precast floor slab according to a fifth embodiment; FIG. 11 is a vertical cross-sectional view of the vicinity of a protruding portion of the fixing structure between the main girder and the precast floor slab according to the sixth embodiment. FIG. 11 is a vertical cross-sectional view showing a lid member installation step of a method of fixing a main girder and a precast floor slab according to a sixth embodiment; FIG. 12 is a vertical cross-sectional view of the vicinity of a projecting portion of the fixing structure between the main girder and the precast floor slab according to the seventh embodiment.

EMBODIMENT OF THE INVENTION Hereafter, embodiment of the fixing structure of a main girder and a precast floor slab and the fixing method of a main girder and a precast floor slab which concerns on this invention is described in detail, referring drawings. As shown in FIGS. 1, 2 and 3, a main girder and precast floor slab fixing structure 1A according to the first embodiment of the present invention includes a main girder 2, a precast floor slab 3A and a filler 9. The main girder 2 is, for example, a steel girder. The main girder 2 has a projection 5 projecting upward from a flange 4 at its upper end. The projecting portion 5 is, for example, a headed stud whose upper end is enlarged in diameter.

The precast floor slab 3A has a lower surface 6 and an upper surface 7. As shown in FIG. The precast floor slab 3</b>A has a housing portion 8 for housing the projecting portion 5 on the lower surface 6 . In the present embodiment, the housing portion 8 is not a conventional box-opening hole penetrating from the upper surface to the lower surface of the precast floor slab, but a concave portion provided in the lower surface 6 of the precast floor slab 3A. The filling material 9 fills the accommodation portion 8 that accommodates the projecting portion 5 . The filler 9 is, for example, non-shrinkage mortar. The filler 9 is placed in a space surrounded by the flange 4 of the main girder 2, the formwork 11 provided on both side edges of the upper surface of the flange 4, the lower surface 6 of the precast floor slab 3A, and the storage section 8. filled.

In this embodiment, the storage section 8 is open to the lower surface 6 of the precast floor slab 3A and closed to the upper surface 7 of the precast floor slab 3A. In the present embodiment, since the storage portion 8 is closed to the upper surface 7 of the precast floor slab 3A, the precast floor is moved from the upper surface 7 of the precast floor slab 3A along the interface 10 between the storage portion 8 and the filler 9. There is no path to the underside 6 of plate 3A. Therefore, the length of the path from the upper surface 7 of the precast floor slab 3A to the lower surface 6 of the precast floor slab 3A along the interface 10 between the container 8 and the filler 9 is infinite. longer than the distance d between the upper surface 7 and the lower surface 6 of the .

Note that the length of the path from the upper surface 7 of the precast floor slab 3A to the lower surface 6 of the precast floor slab 3A along the boundary surface 10 between the container 8 and the filler 9 is the same as in the present embodiment. If 8 is closed to the top surface 7 of the precast slab 3A and the path does not exist, it means that the path length is infinite. Further, the distance d between the upper surface 7 and the lower surface 6 of the precast floor slab 3A means, for example, the thickness of the precast floor slab 3A.

A method of fixing the main girder and the precast floor slab in this embodiment will be described below. As shown in FIG. 4, the precast floor slab 3A is installed on the main girder 2 in a state in which the projecting portion 5 projecting upward from the main girder 2 is accommodated in the accommodation portion 8 of the lower surface 6 of the precast floor slab 3A. An installation process is performed. The order of joining the projecting portion 5 to the flange 4 of the main girder 2 and installing the precast floor slab 3A to the flange 4 of the main girder 2 may be either before or after.

As described above, in the floor slab installation process, the length of the path from the upper surface 7 of the precast floor slab 3A to the lower surface 6 of the precast floor slab 3A along the boundary surface 10 between the housing portion 8 and the filler 9 is A precast floor slab 3A longer than the distance d between the upper surface 7 and the lower surface 6 of the precast floor slab 3A is installed on the main girder 2. - 特許庁Further, in the floor slab installation step, the precast floor slab 3A is installed on the main girder 2, in which the storage section 8 is open to the lower surface 6 of the precast floor slab 3A and closed to the upper surface 7 of the precast floor slab 3A. be done.

As shown in FIG. 3, a filling process is performed to fill the accommodating portion 8 accommodating the protruding portion 5 with the filling material 9 . In the present embodiment, the filling step is performed by, for example, injecting the filling material 9 into the accommodating portion 8 through a hole (not shown) provided in the mold 11 . After solidification of the filler 9, the fixing structure 1A of the main girder 2 and the precast floor slab 3A of this embodiment is completed.

According to this embodiment, the main girder 2 having the projecting portion 5 projecting upward, the precast floor slab 3A having the housing portion 8 for housing the projecting portion 5 on the lower surface 6, and the housing portion 8 housing the projecting portion 5 In the fixed structure 1A for the main girder 2 and the precast floor slab 3A provided with a filler 9 for filling Therefore, there is no path from the upper surface 7 of the precast floor slab 3A to the lower surface 6 of the precast floor 3A along the boundary surface 10 between the container 8 and the filler 9. Therefore, the precast floor There is no path for moisture and salt to enter from the upper surface 7 to the lower surface 6 of the slab 3A, and the durability of the fixing structure 1A between the main girder 2 and the precast floor slab 3A can be improved.

A second embodiment of the present invention will be described below. As shown in FIG. 5, in the fixing structure 1B for the main girder and the precast floor slab of this embodiment, the precast floor slab 3B has a small hole in the center of the upper part of the housing portion 8 that communicates from the housing portion 8 to the upper surface 7. It has an opening 12 which is a part. Therefore, the housing section 8 is open to the lower surface 6 and the upper surface 7 of the precast floor slab 3B.

In this embodiment, the interface 10 between the container 8 and the filler 9 extends vertically from the upper surface 7 to the lower end of the opening 12 , and extends from the lower end of the opening 12 to the peripheral edge of the container 8 . It extends laterally to the upper end of the receiving portion 8 , and extends vertically from the upper end of the peripheral portion of the housing portion 8 to the lower surface 6 . That is, in the present embodiment, the direction in which the boundary surface 10 between the containing portion 8 and the filling material 9 extends from the upper surface 7 to the lower surface 6 of the precast floor slab 3B varies. Therefore, the extending direction of the path p from the upper surface 7 of the precast floor slab 3B to the lower surface 6 of the precast floor slab 3A along the interface 10 between the container 8 and the filler 9 also varies.

In the floor slab installation process of the method of fixing the main girder and the precast floor slab of the present embodiment, the precast floor slab 3B in which the storage section 8 is open to the lower surface 6 and the upper surface 7 of the precast floor slab 3B is installed on the main girder 2. is installed in Further, in the floor slab installation process, the precast floor slab 3B whose direction of extension from the upper surface 7 to the lower surface 6 of the precast floor slab 3B at the boundary surface 10 between the housing portion 8 and the filler 9 varies is placed on the main girder 2. is installed in The filling step of the method of fixing the main girder and the precast floor slab of this embodiment is performed by, for example, injecting the filler 9 from the upper surface 7 of the precast floor slab 3B into the housing portion 8 through the opening 12. . Further, similarly to the first embodiment, the filling process may be performed by, for example, injecting the filling material 9 into the accommodating portion 8 through a hole (not shown) provided in the mold 11 .

In this embodiment, the main girder 2 having the projecting portion 5 projecting upward, the precast floor slab 3B having the housing portion 8 for housing the projecting portion 5 on the lower surface 6, and the housing portion 8 housing the projecting portion 5 are filled. In the fixing structure 1B for the main girder 2 and the precast floor slab 3B, the precast floor slab 3B is fixed from the upper surface 7 of the precast floor slab 3B along the boundary surface 10 between the housing portion 8 and the filler 9. Since the length of the path p leading to the lower surface 6 is longer than the distance d between the upper surface 7 and the lower surface 6 of the precast floor slab 3B, moisture and salt due to rainwater etc. from the upper surface 7 to the lower surface 6 of the precast floor slab 3B is longer than the thickness of the precast floor slab 3B, and the durability of the fixing structure 1B between the main girder 2 and the precast floor slab 3B can be improved.

In other words, in the present embodiment, since the direction in which the boundary surface 10 between the container 8 and the filler 9 extends from the upper surface 7 to the lower surface 6 of the precast floor slab 3B varies, the precast floor slab at the boundary surface is Compared to the case where the direction extending from the upper surface to the lower surface does not change, from the upper surface 7 of the precast floor slab 3B to the lower surface 6 of the precast floor slab 3B along the boundary surface 10 between the housing portion 8 and the filler 9. The length of the path p is lengthened, and the route for moisture and salt intrusion due to rainwater or the like from the upper surface 7 to the lower surface 6 of the precast floor slab 3B is also lengthened, and the durability of the fixing structure 1B between the main girder 2 and the precast floor slab 3B. can be improved.

In addition, in this embodiment, since the storage section 8 is open to the lower surface 6 and the upper surface 7 of the precast floor slab 3B, it is possible to inject the filler 9 from the upper surface 7 of the precast floor slab 3B. Even when the filler 9 is injected from the lower surface 6 of the precast floor slab 3B, it is easy to inject the filler 9 because the air is easily released from the accommodating portion 8 .

In addition, like the fixing structure 1C for the main girder and the precast floor slab according to the third embodiment of the present invention shown in FIG. It may have an opening 12 which is a small hole communicating with the upper surface 7 . Also in this embodiment, the same effects as in the second embodiment are obtained.

A fourth embodiment of the present invention will be described below. As shown in FIG. 7, in this embodiment, as in the second embodiment, the precast floor slab 3D of the fixed structure 1D between the main girder and the precast floor slab is placed in the center of the upper part of the storage section 8. It has an opening 12 which is a small hole communicating from the top surface 7 to the top surface 7 . In addition, in this embodiment, the boundary surface 10 between the storage section 8 and the filler 9 is closer to the upper surface 7 as the opening 12 of the storage section 8 that is open to the upper surface 7 of the precast floor slab 3D is approached. includes a slanted surface 13 that is slanted so that

In the floor slab installation process of the method of fixing the main girder and the precast floor slab of the present embodiment, as described above, the boundary surface 10 between the housing portion 8 and the filler 9 is positioned against the upper surface 7 of the precast floor slab 3D. A precast floor slab 3D including an inclined surface 13 inclined so that the distance from the upper surface 7 becomes shorter as it approaches the opening 12 of the open housing part 8 is installed on the main girder 2. - 特許庁The filling step of the fixing method of the main girder and the precast floor slab of this embodiment is performed in the same manner as in the second embodiment. Note that the inclined surface 13 of this embodiment may be applied to the third embodiment.

In this embodiment, the boundary surface 10 between the storage section 8 and the filler 9 becomes closer to the upper surface 7 as it approaches the opening 12 of the storage section 8 that is open to the upper surface 7 of the precast floor slab 3D. Since the slanted surface 13 is slanted so as to be , when the filling material 9 is injected, the air is easily released from the opening 12 and the air is less likely to accumulate in the accommodating portion 8 .

A fifth embodiment of the present invention will be described below. As shown in FIG. 8, in this embodiment, the precast floor slab 3E of the fixing structure 1E between the main girder and the precast floor slab has an opening 12 in the upper part of the housing portion 8 that communicates from the housing portion 8 to the upper surface 7. have. In this embodiment, the size of the opening 12 on the top surface 7 is the same as the size of the opening on the bottom surface 6, as in a conventional box-cut hole. However, the boundary surface 10 between the containing portion 8 and the filler 9 has a convex portion 14 and a concave portion 15 . Therefore, in the present embodiment, the direction in which the boundary surface 10 between the accommodating portion 8 and the filler 9 extends from the upper surface 7 to the lower surface 6 of the precast floor slab 3E varies. Therefore, the extending direction of the path p from the upper surface 7 of the precast floor slab 3E to the lower surface 6 of the precast floor slab 3E along the interface 10 between the container 8 and the filler 9 also varies. Incidentally, the convex portion 14 and the concave portion 15 of the present embodiment may be applied to the second to fourth embodiments described above.

In this embodiment, as in the second embodiment, since the direction in which the boundary surface 10 between the accommodating portion 8 and the filler 9 extends from the upper surface 7 to the lower surface 6 of the precast floor slab 3E varies, Compared to the case where the direction extending from the upper surface to the lower surface of the precast floor slab on the boundary surface does not change, the precast floor slab extends from the upper surface 7 of the precast floor slab 3E along the boundary surface 10 between the housing portion 8 and the filler 9. The length of the path p leading to the lower surface 6 of the precast floor 3E is lengthened, and the path for moisture and salt to enter from the upper surface 7 of the precast floor slab 3E to the lower surface 6 of the precast floor slab 3E is also lengthened. can improve the durability of the fixing structure 1E.

A sixth embodiment of the present invention will be described below. As shown in FIG. 9, in this embodiment, as in the fifth embodiment, the precast floor slab 3F of the fixing structure 1F between the main girder and the precast floor slab is placed above the housing portion 8 from the top surface of the housing portion 8. It has an opening 12 communicating with 7 . In this embodiment, the size of the opening 12 on the top surface 7 is the same as the size of the opening on the bottom surface 6, as in a conventional box-cut hole. However, the fixing structure 1F between the main girder and the precast floor slab of this embodiment has an area S larger than the opening area _S1 of the opening 12 of the storage section 8 that is open to the upper surface 7 of the precast floor slab 3F. ₂ and covering the opening 12 .

The lid member 16 is made of precast concrete. The precast floor slab 3F has an insert 17 and a notch 18 for fixing the lid member 16. As shown in FIG. The lid member 16 has a shape corresponding to the notch 18 . The lid member 16 has a counterbored hole portion 19 . The lid member 16 placed on the notch portion 18 is fixed by a bolt 20 inserted into the insert 17 through the counterbore portion 19 .

The lid member 16 is made of, for example, a cement-based material. The lid member 16 is made of, for example, ultra high strength fiber reinforced concrete (UFC). An example of the properties of ultra-high strength fiber reinforced concrete will be described below. This ultra-high-strength fiber-reinforced concrete is obtained by hardening a mixture containing, for example, cement, aggregate, mixing water, a chemical admixture for concrete, and reinforcing fibers. Said cements are, for example, ordinary Portland cement, high-early-strength Portland cement, moderate-heat Portland cement, sulfate-resistant Portland cement, or low-heat Portland cement.

As an example, the above-mentioned aggregate has a particle size of 2.5 mm or less, an absolute dry density of 2.5 g/cm ³ or more, a water absorption of 3.0% or less, a clay lump content of 1.0% or less, and a fine particle content of 2.0%. Hereinafter, aggregates having a NaCl content of 0.02% or less are used. This aggregate was judged to be "pale" in the test result of organic impurities according to the organic impurity test method for fine aggregate specified in JISA 1105. In addition, this aggregate has a stability of 10% or less according to the stability test method for aggregates with sodium sulfate specified in JIS A 1122, and the alkali silica reactivity specified in JISA 5308 Annex 1. It is an aggregate whose division by is division A.

The above-mentioned kneading water is, for example, kneading water other than the recovered water specified in JSCE-B 101-2005. The above chemical admixture for concrete is a high performance water reducing agent specified in JISA 6204. Further, the above reinforcing fibers are fibers having a diameter of 0.1 to 0.25 mm, a length of 10 to 24 mm, and a tensile strength of 2×10 ³ N/mm ^{2 or} more. The reinforcing fibers mentioned above may be, for example, steel fibres, high strength aramid fibres, high density polyethylene fibres, or carbon fibres.

The ultra-high-strength fiber-reinforced concrete, for example, the matrix is composed of a binder consisting of Portland cement, a pozzolanic material, and an etrin guide-generating material, an aggregate having a particle size of 2.5 mm or less, water, and a water reducing agent. there is In addition, the reinforcing fibers are steel fibers with a diameter of 0.2 mm and a length of 15 mm (manufacturing error of less than ±2 mm) and a tensile strength of 2 × 10 ³ N/mm ² or more, and a diameter of 0.2 mm and a length of 22 mm (manufacturing error of less than ±2 mm) and tensile strength of 2×10 ³ N/mm ² or more. % may be mixed. In addition, the characteristic values of the ultra-high-strength fiber-reinforced concrete after hardening are compression strength of 150 N/mm ² or more, crack initiation strength of 4 N/mm ² or more, tensile strength of 5 N/mm ^{2 or} more, and hydraulic conductivity of 1 × 10 ^-11 cm/. s, a chloride ion diffusion coefficient of less than 0.14 cm ² /year, and an abrasion coefficient of less than 240 mm ³ /cm ² .

The standard formulation of ultra-high-strength fiber-reinforced concrete is a flow value of 250 ± 20 mm, a mixing water ratio of 15% to the binder, an air content of 2.0%, a mixing water of 195 kg/m ³ , and a binder of 1287 kg/m. ³ , aggregate 905 kg/m ³ , superplasticizer 32.2 kg/m ³ , and reinforcing fiber 137.4 kg/m ³ (1.75 vol.%). Note that if there is concern about dryout, the lid member 16 may not be made of a cement-based material.

A method of fixing the main girder and the precast floor slab in this embodiment will be described below. As shown in FIG. 10, a floor slab installation step and a filling step are performed in the same manner as in the second embodiment. In this embodiment, before the filling material 9 to be filled in the filling process is solidified, the opening of the storage section 8 opened to the upper surface 7 of the precast floor slab 3F installed on the main girder 2 in the floor slab installation process. A lid member installation step is further performed to install the lid member 16 so as to cover the opening 12 with the lid member 16 larger than the opening area S ₁ of the portion 12 .

As described above, the lid member 16 installed in the lid member installation step is made of precast concrete. Also, the lid member 16 installed in the lid member installation process is formed of ultra-high strength fiber reinforced concrete. If the lid member 16 is provided with a small hole for filling the filler 9, the filling process may be performed after the floor slab installation process and the lid member installation process are performed. Also, the lid member 16 of the present embodiment may be applied to the second to fifth embodiments described above.

In this embodiment, a lid member 16 that covers the opening 12 and has an area S2 larger than the opening area _S1 of the opening 12 of the housing portion 8 that opens to the upper surface 7 of the precast floor slab 3F is further provided. In order to prepare, from the upper surface 7 of the precast floor slab 3F, along the boundary surface 10 between the upper surface 7 of the precast floor slab 3F and the lid member 16 and the boundary surface 10 between the storage portion 8 and the filler 9, the precast floor slab 3F The length of the path p leading to the lower surface 6 is lengthened, and the route of entry of moisture and salt due to rainwater and the like from the upper surface 7 of the precast floor slab 3F to the lower surface 6 is also lengthened. It is possible to improve the durability of the fixing structure 1F.

In addition, in the present embodiment, since the lid member installation step is performed before the filler 9 to be filled in the filling step is solidified, the loss of moisture from the filler 9 into the air is reduced, and the drying shrinkage of the filler 9 is reduced. can be reduced.

Also, in this embodiment, the lid member 16 is made of precast concrete, so the quality of the lid member 16 is not affected by the weather at the construction site. Moreover, installation of the lid member 16 is easy.

Moreover, in this embodiment, the lid member 16 is made of ultra-high-strength fiber-reinforced concrete, so that the strength and durability of the lid member 16 can be improved.

A seventh embodiment of the present invention will be described below. As shown in FIG. 11, in this embodiment, a fixing structure 1G between the main girder and the precast floor slab includes a lid member 21, as in the sixth embodiment. However, the precast floor slab 3G has the notch 18 for fixing the lid member 21, but does not have the insert 17. As shown in FIG. Moreover, the lid member 21 is made of cast-in-place concrete. The lid member 21 is made of, for example, ultra-high-strength fiber-reinforced concrete.

In the method of fixing the main girder and the precast floor slab of this embodiment, as in the second embodiment, after the floor slab installation process and the filling process are performed, before the filler material 9 to be filled in the filling process solidifies. Then, a lid member installation step is performed. As described above, the lid member 21 installed in the lid member installation step is made of cast-in-place concrete. Note that the lid member 21 of this embodiment may be applied to the second to fifth embodiments described above.

According to this embodiment, since the lid member 21 is made of cast-in-place concrete, it is difficult for a gap to occur at the interface 10 between the upper surface 7 of the precast floor slab 3G and the lid member 21. Intrusion of moisture and salt due to rainwater or the like from the upper surface 7 to the lower surface 6 can be more effectively prevented.

The present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art, including the embodiment described above. Moreover, it is also possible to configure a modified example using the technical matters described in the above-described embodiments.

1A, 1B, 1C, 1D, 1E, 1F, 1G... fixed structure, 2... main girder, 3A, 3B, 3C, 3D, 3E, 3F, 3G... precast floor slab, 4... flange, 5... protrusion, 6 ...Lower surface 7...Upper surface 8...Accommodating part 9...Filling material 10...Boundary surface 11...Formwork 12...Opening part 13...Slanted surface 14...Convex part 15...Concave part 16...Lid member , 17... insert, 18... notch, 19... counterbore, 20... bolt, 21... cover member, p... path, d... distance, _S1 ... opening area, _S2 ... area.

Claims (11)

a main girder having a protruding portion protruding upward;
a precast floor slab having an accommodation portion for accommodating the projecting portion on its lower surface;
a filling material that fills the accommodating portion that accommodates the protruding portion;
with
The housing portion is a recess provided in the lower surface of the precast floor slab, and is a structure for fixing the main girder and the precast floor slab that does not communicate with the upper surface of the precast floor slab. a main girder having a protruding portion protruding upward;
a precast floor slab having an accommodation portion for accommodating the projecting portion on its lower surface;
a filling material that fills the accommodating portion that accommodates the protruding portion;
with
The length of the path from the upper surface of the precast floor slab to the lower surface of the precast floor slab along the interface between the container and the filler is the distance between the upper surface and the lower surface of the precast floor slab. longer than
The accommodation portion is open to the lower surface and the upper surface of the precast floor slab,
A fixing structure between a main girder and a precast floor slab, further comprising a lid member having an opening area larger than an opening of the opening of the storage section opened to the upper surface of the precast floor slab and covering the opening. The fixing structure of the main girder and the precast floor slab according to claim 2 , wherein the lid member is made of precast concrete. The fixing structure of the main girder and the precast floor slab according to claim 2 , wherein the lid member is formed of cast-in-place concrete. The structure for fixing the main girder and the precast floor slab according to any one of claims 2 to 4 , wherein the lid member is made of ultra-high-strength fiber-reinforced concrete. a floor slab installation step of installing the precast floor slab on the main girder in a state in which the projecting portion projecting upward from the main girder is accommodated in the accommodation portion on the lower surface of the precast floor slab;
a filling step of filling the accommodating portion accommodating the protruding portion with a filler;
with
The accommodation portion of the precast floor slab in the floor slab installation step is a recess provided in the lower surface of the precast floor slab, and is not in communication with the upper surface of the precast floor slab, the main girder and the precast floor slab. and fixing method. In the filling step,
7. The method according to claim 6, wherein a formwork is provided to block the space between the main girder and the lower surface of the precast floor slab, and the filling material is injected through a hole provided in the formwork to fill the accommodation section. method of fixing the main girder and precast floor slab. a floor slab installation step of installing the precast floor slab on the main girder in a state in which the projecting portion projecting upward from the main girder is accommodated in the accommodation portion on the lower surface of the precast floor slab;
a filling step of filling the accommodating portion accommodating the protruding portion with a filler;
with
In the floor slab installation step, the length of the path from the upper surface of the precast floor slab to the lower surface of the precast floor slab along the boundary surface between the housing portion and the filler is installing the precast floor slab on the main girder, wherein the precast floor slab is longer than the distance between the upper surface and the lower surface, and the accommodation portion is open to the lower surface and the upper surface of the precast floor slab;
Before the filling material filled in the filling step is solidified, the opening of the opening of the storage section opened to the upper surface of the precast floor slab installed on the main girder in the floor slab installation step. A method of fixing a main girder and a precast floor slab, further comprising a lid member installation step of installing the lid member so as to cover the opening with a lid member having a larger area. The method of fixing a main girder and a precast floor slab according to claim 8 , wherein the lid member installed in the lid member installation step is made of precast concrete. 9. The method of fixing a main girder and a precast floor slab according to claim 8 , wherein said lid member installed in said lid member installation step is made of cast-in-place concrete. The method of fixing a main girder and a precast floor slab according to any one of claims 8 to 10 , wherein the lid member installed in the lid member installation step is made of ultra-high strength fiber reinforced concrete.

Images