Precast prestress concrete slab and slab structure

Abstract

To reduce slab re-bars.SOLUTION: A PCaPC slab 100 includes a slab body 102 that is formed from fiber-reinforced concrete, tendons 110 that are embedded and tensioned along the entire length of the slab body 102, and connecting bars 120 that are embedded in a slab end 103 of the slab body 102 and protrude laterally from the slab end 103.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to precast prestressed concrete slab slabs and slab structures. [Background technology]

[0002] Patent Document 1 discloses a technology related to a precast prestressed concrete member in which tension is applied to tendons embedded inside using a pretensioning method. This prior art pretensioned PCaPC member has anchorage zones for the tendons at both longitudinal ends, and damping material is wound around the outer periphery of at least one of the upper and lower end reinforcing bars in the central section between the anchorage zones.

[0003] Patent Document 2 discloses a technology related to a pretensioning member that increases the tensile strength of a concrete member by applying compressive stress in advance via tendons. In this prior art pretensioning member, which tensions deformed reinforcing bars to introduce prestress into concrete, the deformed reinforcing bars are unbonded at both ends to provide bond splitting prevention sections, and spiral reinforcing bars are arranged around the deformed reinforcing bars at least in a section adjacent to the center of the bond splitting prevention section, where a force that spreads the concrete radially from the deformed reinforcing bar acts and there is a possibility of bond splitting failure.

[0004] Patent Document 3 discloses a technology related to the floor structure of a building. In this prior art, the beams of the building are formed wider than the columns, and first flat sheaths with flat cylindrical shapes and steel strands inserted therethrough are arranged along the length of the beams, on both sides of the beams, outside the columns. The steel strands in the first flat sheaths are tensioned and both ends are fixed to the concrete edges of the beams or floor slabs. Cement paste is filled into the first flat sheaths to join the steel strands and the first flat sheath together. Also, second flat sheaths with irregularly shaped shapes and steel strands inserted therethrough are arranged lengthwise and widthwise on the floor slab of the building, and the steel strands in the second flat sheaths are tensioned and both ends are fixed to the concrete edges of the beams or floor slabs. Cement paste is filled into the second flat sheaths to join the steel strands and the second flat sheath together. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-155878 [Patent Document 2] Patent No. 4326518 [Patent Document 3] Japanese Patent Application Publication No. 60-5948 Summary of the Invention [Problem to be solved by the invention]

[0006] It is desirable to improve construction efficiency by reducing the amount of slab reinforcement in concrete slabs.

[0007] In view of the above, an object of the present invention is to reduce the amount of slab reinforcing bars. [Means for solving the problem]

[0008] The first aspect is a precast prestressed concrete slab comprising a slab body formed from fiber-reinforced concrete, tendons disposed and embedded along the entire length of the slab body and tensioned, and connecting bars embedded in the ends of the slab body and protruding laterally from the ends of the slab body.

[0009] In the first aspect of the precast prestressed concrete slab, rigidity is ensured by the tension of the tendons and the fibers, and the bending stress acting on the slab body due to the tension is handled by the fibers, so the amount of slab rebar in the precast prestressed concrete slab can be reduced.

[0010] The second aspect is a slab structure in which the precast prestressed concrete slab plates of the first aspect are installed on both sides of a beam, and connecting bars protruding laterally from the ends of the slab body are embedded in the beam.

[0011] In the slab structure of the second embodiment, the precast prestressed concrete slab and the beam are connected by connecting bars, which improves construction efficiency.

[0012] A third aspect is a slab structure described in the second aspect, in which fall prevention bars protrude from the ends of the slab body of the precast prestressed concrete slab plate and are embedded in the beams.

[0013] In the third embodiment of the slab structure, the fall prevention reinforcement prevents the precast prestressed concrete slab from falling, so the amount of reinforcement needed to prevent falling is reduced. [Effects of the Invention]

[0014] According to the present invention, the amount of slab reinforcing bars can be reduced. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a cross-sectional view of the slab structure of the first embodiment taken along the X direction. [Figure 2] FIG. 2 is a cross-sectional view of a main part of FIG. [Figure 3] This is a diagram showing the end of the tendon fixed with an anchoring fitting. [Figure 4] FIG. 2 is a plan view of the slab structure of the first embodiment. [Figure 5] FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. [Figure 6] FIG. 3 is a cross-sectional view corresponding to FIG. 2 of a slab structure according to a modified example of the first embodiment. [Figure 7] FIG. 3 is a cross-sectional view corresponding to FIG. 2 of a slab structure according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] First Embodiment A precast prestressed concrete slab and slab structure according to a first embodiment of the present invention will be described.

[0017] In each drawing, two directions perpendicular to the horizontal direction are the X direction and the Y direction, respectively indicated by the arrows X and Y. The vertical direction perpendicular to the X direction and the Y direction is the Z direction, indicated by the arrow Z.

[0018] Each drawing is merely a schematic representation. The dimensions and proportions of each element shown in the drawings may not necessarily correspond to those of the actual product. The dimensions, proportions, and number of each element may not necessarily correspond between multiple drawings. Hatching representing cross sections has been omitted if it makes the view difficult to see.

[0019] In addition, descriptions of configurations that are not directly related to the present invention and well-known configurations may be omitted or simplified.

[0020] These also apply to the modified example and second embodiment described later.

[0021] [Precast prestressed concrete slab] First, we will explain the precast prestressed concrete slab. Hereinafter, the precast prestressed concrete slab will be referred to as the "PCaPC slab." Also, each direction refers to the state when the slab 10 (see Figures 1 to 4) described below is installed.

[0022] As shown in Figure 4, the PCaPC slab slab 100 is a large rectangular slab slab with the X direction as the longitudinal direction in plan view. The PCaPC slab slab 100 is applied with tension (prestress) in the X direction. The PCaPC slab slab 100 is manufactured in a factory or the like separate from the construction site.

[0023] As shown in FIGS. 1 and 2, the PCaPC slab 100 is composed of a slab body 102, tendons 110, connecting bars 120, and fall prevention bars 130.

[0024] The slab body 102 is made of fiber-reinforced concrete. Fiber-reinforced concrete is a concrete material in which synthetic fibers, steel fibers, etc. are combined with concrete. The slab body 102 of this embodiment is formed with a slab-side protrusion 104 that protrudes laterally from the lower part of the slab end 103 in the X direction, in this embodiment in the X direction (see also Figure 3). The upper side of the slab-side protrusion 104 at the slab end 103 is designated as a step portion 106 (see also Figure 3).

[0025] The tendons 110 of this embodiment are made of PC steel wires and are embedded in a tensioned state over the entire length in the X direction of the slab body 102. The tendons 110 arranged along the X direction may be provided in multiple pieces at intervals in the Y direction in a plan view.

[0026] The tendon 110 of this embodiment is embedded with its underside curved in a convex shape in the slab body 102. The end 112 of the tendon 110 protrudes from the step 106 of the slab end 103 of the slab body 102 (see also Figure 3).

[0027] As shown in Figure 3, the end 112 of the tendon 110 protruding from the step 106 of the slab body 102 of the PCaPC slab slab 100 is fixed to the step 106 by an anchoring fitting 150. In this embodiment, a sheath pipe 152 into which the tendon 110 is inserted is arranged before concrete is poured, and after concrete is poured, the tendon 110 is inserted and tensioned to introduce tension force (prestress). Note that the connecting bars 120 and fall prevention bars 130 are not shown in Figure 3.

[0028] As shown in Figures 1 and 2, the connecting bar 120 of this embodiment is made of steel bar and is embedded in the upper end of the slab end 103 in the slab main body 102, and protrudes laterally from the step portion 106, which in this embodiment is in the X direction.

[0029] The fall prevention bar 130 is an L-shaped metal piece that is embedded in the lower end of the slab end 103 in the slab main body 102 and protrudes upward from the upper surface of the slab-side protrusion 104. A disk-shaped anchoring portion 132 is provided at the protruding upper end of the fall prevention bar 130.

[0030] Here, in the PCaPC slab slab 100 of this embodiment, slab reinforcement, specifically slab main reinforcement and distribution reinforcement arranged at the upper and lower ends, are not embedded.

[0031] 4 and 5, grooves 140 are formed on the top surface of the long sides 108 of the slab body 102 of the PCaPC slab slab 100, which is rectangular in plan view and extends along the X direction, along the Y direction. Multiple grooves 140 are formed at intervals in the X direction. Note that no grooves 140 are formed on the long sides 108 of the PCaPC slab slab 100 that are joined to beams 31 that extend along the X direction, as will be described later.

[0032] [Slab structure] Next, the slab structure 12 of the slab 10 constructed using the PCaPC slab slab 100 will be described.

[0033] As shown in FIG. 4, the slab 10 is composed of multiple PCaPC slab panels 100 lined up and joined in the Y direction. In plan view, the PCaPC slab panels 100 are spanned by columns 20 and beams 30 that run along the Y direction and are joined to the columns 20. The grooves 140 of the PCaPC slab panels 100 adjacent in the Y direction are connected to each other. The beams that run along the X direction and are joined to the columns 20 are denoted by the reference numeral 31. In this embodiment, the columns 20, beams 30, and beams 31 are made of reinforced concrete.

[0034] As shown in Fig. 2, in the beam 30 extending along the Y direction in this embodiment, beam main reinforcements 32 are arranged at the upper and lower ends, respectively, and rectangular frame-shaped shear reinforcement bars 34 are arranged so as to surround the beam main reinforcement bars 32. Note that, like the beam 30, a beam 31 extending along the X direction (see Fig. 4) also has beam main reinforcements 32 arranged at the upper and lower ends, respectively, and rectangular frame-shaped shear reinforcement bars 34 arranged so as to surround the beam main reinforcement bars 32. In addition, in the column 20 (see Fig. 4) of this embodiment, column main reinforcement bars and shear reinforcement bars are arranged.

[0035] 1 and 2, a beam-side protrusion 36 that protrudes laterally, in the X direction in this embodiment, is formed at the upper end of the beam 30 that extends along the Y direction in this embodiment. Therefore, the cross section of the beam 30 along the Y direction is T-shaped.

[0036] The PCaPC slab slab 100 is installed on both sides of the beam 30 in the X direction and spans across it (see also Figure 3). The connecting bars 120 protruding from the step portion 106 are embedded in the upper ends of the beams 30, and the connecting bars 120 are connected to each other with lap joints. The connecting bars 120 are installed on only one side of the beam 30 at the end of the X direction of the slab 10 and span across it.

[0037] The beam-side protrusion 36 is constructed on top of the slab-side protrusion 104. The portion of the fall prevention reinforcement 130 that protrudes from the top surface of the slab-side protrusion 104 is embedded in and fixed to the beam-side protrusion 36.

[0038] As shown in Figures 4 and 5, connecting bars 142 made of reinforcing bars are placed in grooves 140 connecting adjacent PCaPC slab panels 100 in the Y direction, and then grout material 149 (see Figure 5) is filled into the grooves 140. This connects and integrates the PCaPC slab panels 100 adjacent in the Y direction.

[0039] One of the long sides 108 of the PCaPC slab panels 100 that make up both sides of the slab 10 in the Y direction does not have a groove 140, but has a joint bar 145 that protrudes in the Y direction embedded in advance. The joint bar 145 is also embedded in the upper end of the beam 31.

[0040] [Construction method] Next, an example of a method for constructing the slab structure 12 of this embodiment will be described.

[0041] As shown in Figures 2 and 5, a U-shaped formwork 200 for the beam 30 (see Figure 2) and a U-shaped formwork 201 for the beam 31 (see Figure 5) are installed. The PCaPC slab slab 100 is placed on the upper end 202 of the formwork 200 and the upper end 203 of the formwork 201. Also, as shown in Figure 1, the PCaPC slab slab 100 is supported by shoring 210. Then, the beam main reinforcement 32 and the shear reinforcement 34 are arranged to construct the beams 30 and 31. Note that for ease of understanding, a gap is shown between the shoring 210 and the PCaPC slab slab 100, but in reality there is no gap.

[0042] [Effect] Next, the operation of this embodiment will be described.

[0043] The PCaPC slab slab 100 has a slab body 102 made of fiber-reinforced concrete. Additionally, tendons 110 are curved and embedded in the slab body 102. Therefore, the rigidity of the PCaPC slab slab slab 100 is ensured by the tension of the tendons 110 and the fibers, and the bending stress acting on the slab body 102 due to the tension is handled by the fibers.

[0044] In addition, the connecting bars 120 protruding from the step portion 106 of the PCaPC slab slab 100 are embedded in the upper ends of the beams 30, and the connecting bars 120 are connected to each other with lap joints.

[0045] Therefore, slab reinforcement is not arranged in the PCaPC slab slab 100. Specifically, the PCaPC slab slab slab 100 does not have main slab reinforcement and distribution reinforcement arranged at the upper and lower ends.

[0046] The PCaPC slab slabs 100 and the beams 30 are connected by connecting bars 120 that protrude in the X direction. Adjacent PCaPC slab slabs 100 in the X direction are connected by lap joints via the connecting bars 120. This reduces the amount of reinforcing bars required for connection. Furthermore, by forming the beam-side protrusions 36 on the beams 30, the anchorage and joint allowance of the connecting bars 120 are increased.

[0047] Furthermore, connecting bars 142 made of reinforcing bars are placed in the grooves 140 connecting adjacent PCaPC slab panels 100 in the Y direction, and then grout is filled into the grooves 140. This connects and integrates adjacent PCaPC slab panels 100 in the Y direction. This reduces the amount of reinforcing bars needed to connect adjacent PCaPC slab panels 100.

[0048] In addition, since the fall prevention bars 130 protruding from the slab body 102 of the PCaPC slab panel 100 are embedded in the beam-side protruding portion 36 of the beam 30, the amount of reinforcing bars used to prevent falling is reduced.

[0049] In this way, in the PCaPC slab slab 100 and slab structure 12 of this embodiment, the slab reinforcing bars and other reinforcing bars are reduced, thereby improving construction efficiency.

[0050] <Modification> Next, a modified example of the beam along the X direction will be described.

[0051] 6 is constructed using a half-precast concrete beam 232. The upper side of the half-precast concrete beam 232 in the beam 230 is a cast-in-place section 236 that is constructed by casting on-site.

[0052] In this modified example, the PCaPC slab 100 is placed on the upper surface 234 of the X-direction end of the half precast concrete beam 232. This reduces the number of formwork 200 (see FIG. 2) and formwork 201 (see FIG. 5), improving construction efficiency.

[0053] Second Embodiment A precast prestressed concrete slab and slab structure according to a second embodiment of the present invention will be described. Note that the same reference numerals are used to designate the same components as those in the first embodiment, and redundant descriptions will be omitted or simplified.

[0054] [Precast prestressed concrete slab] As shown in Figure 7, the PCaPC slab slab 300 is a large rectangular slab slab with its longitudinal direction in the X direction when viewed from above. The PCaPC slab slab 300 is tensioned in the X direction. The PCaPC slab slab 300 is manufactured in a factory or the like separate from the construction site.

[0055] The PCaPC slab 300 is configured to include a slab body 302, tendons 110, and studs 320 as an example of connectors.

[0056] The slab body 302 is made of fiber-reinforced concrete. The slab body 302 of this embodiment has a slab-side protrusion 304 that protrudes laterally from the top of the slab end 303 in the X direction, in this embodiment, in the X direction.

[0057] The tendons 110 are made of PC steel wires and are embedded in the slab body 102 over the entire length in the X direction while tension is applied. A plurality of tendons 110 arranged along the X direction may be provided at intervals in the Y direction in plan view. The tendons 110 of this embodiment are embedded in the slab body 102 with their undersides curved in a convex shape. The ends 112 of the tendons 110 protrude from the slab-side protrusions 304 of the slab body 302. The ends 112 of the tendons 110 are fixed by anchoring fittings 150 (see Figure 3).

[0058] In this embodiment, a stud 320 having a disk-shaped fixing portion 322 at its tip is embedded in the upper end of the slab end portion 303 of the slab main body 302 and protrudes laterally from the slab side protrusion 304, in the X direction in this embodiment.

[0059] Here, in the PCaPC slab slab 300 of this embodiment, slab reinforcement, specifically slab main reinforcement and distribution reinforcement arranged at the upper and lower ends, are not embedded.

[0060] Although not shown, similar to the first embodiment, grooves 140 (see FIGS. 4 and 5) are formed on the top surface of the long sides of the slab body 302, which is rectangular in plan view and extends along the X direction, along the Y direction. Multiple grooves 140 are formed at intervals in the X direction (see FIGS. 4 and 5). One of the long sides of the PCaPC slab slab 300, which constitute both sides of the slab 11 in the Y direction (described later), does not have grooves 140, but has pre-embedded joint reinforcements 145 protruding in the Y direction (see FIGS. 4 and 5).

[0061] [Slab structure] Next, the slab structure 13 of the slab 11 constructed using the PCaPC slab slab 300 will be described.

[0062] As shown in Fig. 7, the slab 11 is composed of multiple PCaPC slab panels 300 lined up and joined in the Y direction. In a plan view, the PCaPC slab panels 300 are suspended across beams 330 that run along the Y direction and are joined to columns. In this embodiment, the beams 330 running along the Y direction have main beam reinforcement bars 32 arranged at the top and bottom ends, and rectangular frame-shaped shear reinforcement bars 34 arranged to surround the main beam reinforcement bars 32.

[0063] The PCaPC slab slab 300 is installed on both sides of the beam 330 in the X direction and spans it. At the lower end of the beam 330, which is aligned in the Y direction in this embodiment, a beam-side protrusion 332 is formed that protrudes laterally, in the X direction in this embodiment. The slab-side protrusion 304 of the PCaPC slab slab slab 300 is configured to be positioned above the beam-side protrusion 332.

[0064] The studs 320 protruding from the slab-side protrusions 304 are embedded in the beam-side protrusions 36 and are connected by being fixed to each other.

[0065] Although not shown in the drawings, similarly to the first embodiment, connecting bars 142 made of reinforcing bars are placed in the grooves connecting the PCaPC slab panels 300 adjacent in the Y direction, and then grout material is filled into the grooves 140. This connects and integrates the PCaPC slab panels 300 adjacent in the Y direction.

[0066] Although not shown, in the first embodiment, one long side of the PCaPC slab panels 300 that form both sides of the slab 11 in the Y direction does not have a groove 140, but has a joint bar 145 (FIGS. 4 and 5) embedded in advance that protrudes in the Y direction. The joint bar 145 is embedded in the upper end of the beam 31.

[0067] [Construction method] Next, an example of a construction method for the slab structure 13 of this embodiment will be described.

[0068] As shown in Figure 7, hat-shaped formwork 400 for beam 330 and formwork 201 for beam 31 (see Figure 5) are installed. PCaPC slab slab 300 is placed on the end upper surface 404 of the flange portion 402 of formwork 400 and the upper end 203 of formwork 201 (see Figure 5). In addition, PCaPC slab slab 300 is supported by shoring 210 (see Figure 1). Then, beam main reinforcement 32 and shear reinforcement 34 are arranged, and beam 330 and beam 31 are constructed.

[0069] [Effect] Next, the operation of this embodiment will be described.

[0070] The PCaPC slab slab 300 has a slab body 302 made of fiber-reinforced concrete. The tendons 110 are curved and embedded in the slab body 302. Therefore, the PCaPC slab slab slab 300 reduces the amount of slab rebar.

[0071] In addition, the studs 320 protruding from the slab-side protrusion 304 of the PCaPC slab panel 300 are embedded in the upper ends of the beams 30, and the studs 320 are mutually fixed, thereby reducing the amount of reinforcing bars required for connection.

[0072] In addition, the slab-side protrusion 304 of the PCaPC slab panel 300 is configured to be arranged on top of the beam-side protrusion 332 of the beam 330. This reduces the need for reinforcement for preventing falling and the need for fall prevention reinforcement 130 (see FIG. 2).

[0073] In this way, in the PCaPC slab slab 300 and slab structure 13 of this embodiment, the slab reinforcing bars and other reinforcing bars are reduced, thereby improving construction efficiency.

[0074] <Other> The present invention is not limited to the above embodiment.

[0075] For example, in the above-described embodiments, the PCaPC slab slabs 100, 300 do not have any slab main reinforcement or distribution bars embedded at the top and bottom ends, but this is not limited to this. If necessary, slab reinforcement such as slab main reinforcement and distribution bars may be arranged in the slab body 102, 302. In this case, too, the amount of slab reinforcement can be reduced compared to when there are no tendons 110 and fiber-reinforced concrete is used as the material.

[0076] For example, the beams 30, 31 and the column 20 are made of reinforced concrete, but this is not limited to this. The beams and columns may be made of steel-framed reinforced concrete or steel-framed. In the case of steel-framed construction, the PCaPC slab panels 100, 300 are placed on the steel beams, and concrete or the like is poured on top of the steel beams, and the connecting bars 120 and studs 320 are embedded.

[0077] Furthermore, for example, in the PCaPC slab panels 100 and 300 of the above-described embodiments, tension (prestress) is introduced to the tendons 110 in a factory separate from the construction site, but this is not limited to this. Tension (prestress) may be introduced to the tendons 110 after they are transported to the construction site.

[0078] Furthermore, the present invention can be embodied in various forms without departing from the spirit and scope of the present invention. A plurality of embodiments and modifications can be implemented in combination as appropriate. [Explanation of symbols]

[0079] 10 Slabs 11 Slab 12 Slab structure 13 Slab structure 100 Precast prestressed concrete slab 102 Slab body 103 Slab Edge 110 Tensile material 120 Connecting Muscles 130 Fall prevention bars 300 Precast prestressed concrete slab 302 Slab body 303 Slab Edge 320 Stud (example of connecting bar)

Claims

1. a slab body formed of fiber-reinforced concrete; Tendons that are disposed and embedded over the entire length of the slab body and to which tension is applied; A connecting bar embedded in the end of the slab body and protruding laterally from the end of the slab body; Precast prestressed concrete slab plate.

2. The precast prestressed concrete slab of claim 1 is installed on both sides of a beam, and connecting bars projecting laterally from the ends of the slab body are embedded in the beam. Slab structure.

3. Fall prevention bars protrude from the end of the slab body of the precast prestressed concrete slab, The fall prevention bar is embedded in the beam.

3. The slab structure of claim 2.

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