Foundation structure and construction method of foundation structure

Abstract

In a foundation structure where the edge of the floor slab cantilevered over the footing of the foundation, both the vertical and horizontal lines between the floor slab and the foundation are separated. [Solution] The foundation structure 100 comprises a foundation section 110 having a footing section 120 constructed on the ground and a rising section 131 rising from the footing section 120; an L-shaped precast concrete member 140 that extends from the upper surface 122 of the footing section 120 onto the ground, with a first gap 102 and a second gap 14 formed between the upper surface 122 of the footing section 120 and the side surface 132 of the rising section 131, respectively; and a floor slab 150 that is constructed by pouring concrete onto the ground with the precast concrete member 140 as part of the formwork and that can be seen projecting above the upper surface 122 of the footing section 120.

Description

Technical Field

[0001] The present invention relates to a foundation structure and a method for constructing the foundation structure.

Background Art

[0002] Patent Document 1 discloses a technology related to a dirt floor. In this prior art patent, there is provided a dirt slab constructed by placing concrete on the ground in a state separated from the foundation part of a building, and in the dirt floor that constitutes the floor surface of the building by this dirt slab, a partition wall extending downward from the lower surface of the dirt slab is provided in a manner of partitioning the ground below the dirt slab into a plurality of divided regions.

[0003] Patent Document 2 discloses a technology related to a vibration isolation floor structure provided with a dirt slab. In this prior art patent, there are provided a dirt slab extending over a plurality of foundation structures, a ground-side vibration isolation material interposed between the dirt slab and the ground part in a state of cutting off the dirt slab and the ground part, and a foundation-side vibration isolation material interposed between the dirt slab and the foundation structure in a state of cutting off the dirt slab and the foundation structure.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the case of a foundation structure where the end of the dirt slab jumps out onto the footing part of the foundation part, not only the edge cut of the vertical line between the end of the dirt slab and the side surface of the upright part rising from the footing part of the foundation part but also the edge cut of the horizontal line between the end of the dirt slab and the upper surface of the footing part need to be considered, and ingenuity is required.

[0006] The purpose of this invention is to separate both the vertical and horizontal lines between the floor slab and the foundation in a foundation structure where the end of the floor slab cantilever over the footing of the foundation. [Means for solving the problem]

[0007] The first embodiment is a foundation structure comprising: a foundation having a footing section constructed on the ground and a rising section rising from the footing section; an L-shaped precast concrete member provided with gaps formed between the upper surface of the footing section and the side surface of the rising section, and projecting onto the ground from the upper surface of the footing section; and a floor slab constructed by pouring concrete onto the ground using the precast concrete member as part of the formwork, and projecting above the upper surface of the footing section.

[0008] In the first embodiment of the foundation structure, the L-shaped precast concrete member has gaps formed between the upper surface of the footing and the side surface of the rising section. Concrete is then poured into the precast concrete member as part of the formwork to construct the floor slab. Therefore, gaps are formed between the floor slab and the upper surface of the footing and the rising section of the foundation, and the two are almost completely separated. In other words, in a foundation structure where the end of the floor slab cantilever over the footing of the foundation, both the vertical and horizontal lines between the floor slab and the foundation are separated. Consequently, compared to a case where only the vertical line is separated, vibrations transmitted to the floor slab through the foundation, especially micro-vibrations, are reduced.

[0009] The second aspect is a construction method for a foundation structure, comprising the steps of: constructing a foundation on the ground having a footing and a rising portion extending from the footing; installing the precast concrete member on the ground such that a support member attached by penetrating the L-shaped precast concrete member is brought into contact with the upper surface of the footing, and gaps are formed between the upper surface of the footing and the side surface of the rising portion; constructing a floor slab by pouring concrete into the precast concrete member as part of the formwork; removing the support member after the concrete of the floor slab has hardened; and pouring concrete onto the floor slab.

[0010] In the construction method of the foundation structure of the second embodiment, in the process of constructing the floor slab by pouring concrete using precast concrete members as part of the formwork, the floor slab is supported by a support member that abuts against the upper surface of the footing, and the load of the floor slab acts on the footing through the support member. Then, by removing the support member after the concrete of the floor slab has hardened, the load of the floor slab no longer acts on the footing of the foundation. Therefore, in a foundation structure where the end of the floor slab cantilever over the footing of the foundation, both the vertical and horizontal lines between the floor slab and the foundation are separated. Consequently, compared to the case where only the vertical line is separated, vibrations transmitted to the floor slab through the foundation, especially micro-vibrations, are reduced.

[0011] The third aspect is a construction method for the foundation structure described in the second aspect, wherein the precast concrete member has a hole formed in it, and the support member is attached by inserting it through the hole.

[0012] In the construction method of the foundation structure of the third embodiment, the support member can be easily inserted through the precast concrete member by passing it through a hole formed in the precast concrete member. [Effects of the Invention]

[0013] According to the present invention, in a foundation structure where the end of the floor slab can overhangs the footing of the foundation, it is possible to separate both the vertical and horizontal lines between the floor slab and the foundation. [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view showing a cross-section along line 1-1 in Figure 2 of the basic structure of one embodiment. [Figure 2] This is a plan view of the foundation structure of one embodiment. [Figure 3] This is a cross-sectional view showing the state after the precast concrete members have been installed in the construction method of the foundation structure shown in Figure 1. [Figure 4] This is a cross-sectional view showing the construction of the main part of the floor slab after concrete has been poured using precast concrete members as part of the formwork, following the construction method of the foundation structure in Figure 1 as shown in Figure 3. [Figure 5] This is a cross-sectional view showing the construction method of the foundation structure in Figure 1, after the threaded reinforcing bars have been removed following Figure 4. [Figure 6] Figure 5 is a cross-sectional view showing the construction method of the foundation structure in Figure 1, with the top concrete section of the floor slab later constructed. [Figure 7] This is a cross-sectional view showing a cross-section of the basic structure of one embodiment along line 7-7 in Figure 2. [Modes for carrying out the invention]

[0015] <Embodiment> An embodiment of the present invention, a foundation structure, and a method for constructing the foundation structure are described below. The two orthogonal horizontal directions are denoted as the X and Y directions, and are indicated by arrows X and Y, respectively. The vertical direction perpendicular to the X and Y directions is denoted as the Z direction, and is indicated by arrow Z.

[0016] The drawings are only schematically shown. Dimensions, ratios, etc. of each element shown in the drawings may not necessarily match the actual ones. Also, between multiple drawings, dimensions, ratios, numbers, etc. of each element may not necessarily match. When it becomes difficult to view, hatching representing a cross-section may be omitted.

[0017] In addition, regarding configurations not directly related to the present invention and well-known configurations, etc., the description may be omitted or simplified.

[0018] [Foundation Structure] First, the foundation structure of an embodiment of the present invention will be described.

[0019] As shown in FIGS. 1 and 7, the foundation structure 100 is composed of a concrete foundation part 110 made of reinforced concrete and a dirt floor slab 150 made of reinforced concrete. The foundation part 110 of this embodiment is a strip foundation with an inverted T-shaped cross-section having a footing part 120 and a standing part 131 rising from the footing part 120. A foundation beam part 129 (also refer to FIG. 2) is provided across the footing part 120 and the standing part 131 in the foundation part 110. Reinforcing bars (not shown) are arranged in the foundation part 110. Also, a floor slab 102 is joined to the upper end of the standing part 131 of the foundation part 110.

[0020] The foundation part 110 of the foundation structure 100 extends in the Y direction as shown in FIG. 2. Also, columns 50 are joined to the standing part 131 of the foundation part 110 (also refer to FIG. 1). The columns 50 are provided at intervals in the Y direction. The columns 50 of this embodiment are steel columns, and the end parts 52 are embedded in the standing part 131, but it is not limited to this. Note that the periphery of the part where the column 50 is joined in the standing part 131 of the foundation part 110 is a column form 130 (also refer to FIG. 1). As shown in FIG. 1, the column form 130 constitutes the upper part of the foundation beam part 129 in the standing part 131. The part where the column form 130 is formed in the standing part 131 protrudes to the side opposite to the dirt floor slab 150 more than the part other than the column form 130 (refer to FIG. 7) (also refer to FIG. 2). Also, the base plate 51 at the lower end of the column 50 is located above the foundation beam part 129.

[0021] As shown in Figures 1 and 7, the foundation 110 and floor slab 150 of the foundation structure 100 are constructed on a ground improvement body 200, which is an example of ground. The ground improvement body 200 constructed on the ground in this embodiment has a foundation-side ground improvement section 210 and a floor slab-side ground improvement section 250. The floor slab-side ground improvement section 250 is constructed on the ground adjacent to the foundation-side ground improvement section 210, and its upper surface 252 is higher than the upper surface 212 of the foundation-side ground improvement section 210.

[0022] In this embodiment, the foundation 110 is constructed on top of the foundation-side ground improvement section 210, and the floor slab 150 is constructed on top of the floor slab-side ground improvement section 25. The upper surface 122 of the footing section 120 of the foundation 110 is lower than the upper surface 252 of the floor slab-side ground improvement section 250. There is a gap 202 between the side surface 124 of the footing section 120 and the upper side surface 254 of the floor slab-side ground improvement section 250, and this gap 202 is backfilled with soil. This backfilled portion is referred to as the soil section 10.

[0023] The floor slab 150 is constructed using precast concrete members 140 as part of the formwork. The precast concrete members 140 consist of a first plate portion 142 and a second plate portion 144. In this embodiment, an L-shaped retaining wall is used for the precast concrete members 140, but it is not limited to this.

[0024] The end portion 141 of the first plate portion 142 of the precast concrete member 140 is placed on the ground improvement portion 250 on the floor slab side and fixed with metal fittings 12 and screws, etc. The precast concrete member 140 protrudes from the ground improvement portion 250 on the floor slab side toward the foundation portion 110. Therefore, the first plate portion 142 of the precast concrete member 140 has a first gap 102 between the upper surface 122 of the footing portion 120 of the foundation portion 110 and the soil portion 10.

[0025] In this embodiment, a sheet-like insulating material 103 made of a soft material such as polyurethane is provided in the first gap 102. Also, a second gap 104 (see also Figure 2) is formed between the second plate portion 144 of the precast concrete member 140 and the side surface 132 of the rising portion 131 of the foundation portion 110.

[0026] A hole 143 is formed in the first plate portion 142 of the precast concrete member 140, and a mounting member 300 is provided above this hole 143. The mounting member 300 will be described later.

[0027] A floor slab 150 is constructed on top of the improved ground section 250 on the floor slab side. As mentioned above, the floor slab 150 is constructed by pouring concrete into precast concrete members 140 as part of the formwork. The precast concrete members 140 also constitute a part of the slab end 152 of the floor slab 150.

[0028] The floor slab 150 has a structure in which the slab end 152 cantilever out from the floor-side ground improvement section 250 to the foundation section 110, forming a first gap 102 between the slab end 152 and the upper surface 122 of the footing section 120 and the soil section 10 of the foundation section 110, and a second gap 104 is formed between the slab end 152 and the side surface 132 of the rising section 131.

[0029] From another perspective, the L-shaped precast concrete member 140 is provided with a first gap 102 and a second gap 104 formed between the upper surface 122 of the footing portion 120 of the foundation portion 110 and the side surface 132 of the rising portion 131, respectively, and extends from the upper surface 122 of the footing portion 120 to the ground improvement portion 250 on the floor slab side.

[0030] The floor slab 150 is reinforced with steel bars. In this embodiment, the lower reinforcement bars 170, designated as the upper reinforcement bars 160, and the shear reinforcement bars 172 are arranged. The foundation portion 110 side of the upper reinforcement bars 160 is bent downwards. The portion bent downwards is referred to as the bent portion 162. One end of the shear reinforcement bars 172 is anchored to the floor slab 150, and the other end is joined to the second plate portion 144 of the precast concrete member 140 with a post-installed anchor or the like.

[0031] In addition, L-shaped metal fittings 14 and 16 are attached to the opposing corners of the floor slab 150 and the rising portion 131 of the foundation 110, respectively.

[0032] [Mounting components] Next, we will describe the mounting member 300 provided on the first plate portion 142 of the precast concrete member 140.

[0033] As shown in Figures 3, 5, and 6, the mounting member 300 is composed of a steel pipe 302 and flange portions 310 and 320 joined to the upper and lower ends of the steel pipe 302, respectively. Screw holes 312 and 322 are formed in the center of the flange portions 310 and 320, respectively. The diameters of the screw holes 312 and 322 are smaller than the inner diameter of the steel pipe 302.

[0034] The mounting member 300 is fixed to the first plate portion 142 of the precast concrete member 140 such that the center of the steel pipe 302 coincides with or substantially coincides with the center of the hole 143 in the first plate portion 142 of the precast concrete member 140. In this embodiment, a chemical anchor (registered trademark) 330 embedded around the hole 143 in the first plate portion 142 of the precast concrete member 140 is inserted through a fixing hole (not shown) formed on the outer circumference of the lower flange portion 320 and fixed with a nut 332, but is not limited to this.

[0035] As shown in Figure 3, threaded reinforcing bars 350, with threaded nodes on their surface, are screwed into threaded holes 312 and 322 in the flange portions 310 and 320 of the mounting member 300. Note that threaded reinforcing bars 350 are an example of a support member.

[0036] The lower end 352 of the threaded reinforcing bar 350 is inserted through the hole 143 in the first plate portion 142 of the precast concrete member 140 and protrudes from the first plate portion 142. The lower end 352 of the threaded reinforcing bar 350 also penetrates the insulating material 103 and abuts against the upper surface 122 of the footing portion 120 of the foundation portion 110. The upper end 354 of the threaded reinforcing bar 350 protrudes from the upper flange portion 310.

[0037] [Construction methods for foundation structures] Next, an example of a construction method for the foundation structure will be described. The description will begin from the state in which the ground improvement body 200 and the foundation section 110 have been constructed. Also, a sheet-like insulating material 103 is provided on the upper surface 122 of the footing section 120 of the foundation section 110. Figures 3 to 6, which illustrate the construction method, show the main parts of the cross-section in Figure 1, and the cross-section in Figure 7 is similar.

[0038] First, as shown in Figure 3, the mounting member 00 is attached in advance to the hole 143 in the first plate portion 142 of the precast concrete member 140. The threaded reinforcing bar 350 is screwed into the threaded holes 312 and 322 of the flange portions 310 and 320 so that it protrudes from the first plate portion 142 of the precast concrete member 140. The amount of protrusion of the lower end portion 352 of the threaded reinforcing bar 350 from the first plate portion 142 is adjusted in advance so that it matches or approximately matches the vertical width of the first gap 102.

[0039] The end portion 141 of the first plate portion 142 of the precast concrete member 140 is placed on the ground improvement portion 250 on the floor slab side and fixed with metal fittings 12 and screws, etc. The lower end portion 352 of the threaded reinforcing bar 350 protruding from the first plate portion 142 of the precast concrete member 140 is passed through the insulating material 103 and brought into contact with the upper surface 122 of the footing portion 120 of the foundation portion 110.

[0040] Furthermore, the amount of protrusion of the lower end 352 of the threaded reinforcing bar 350 may be adjusted afterward so that it matches or approximately matches the vertical width of the first gap 102.

[0041] Next, as shown in Figure 4, the upper reinforcement bars 160, lower reinforcement bars 170, and shear reinforcement bars 172 are placed, and concrete is poured onto the precast concrete member 140 as part of the formwork to construct the main part 150A of the floor slab 150, excluding the top concrete section 250B which will be described later. At this time, the upper flange portion 310 of the mounting member 300 and the upper end portion 354 of the threaded reinforcement bars 350 are exposed.

[0042] As shown in Figure 5, after the concrete has hardened, the threaded reinforcing bars 350 are removed from the mounting member 300, and the threaded holes 312 in the upper flange portion 310 are sealed. Then, as shown in Figure 6, the top concrete portion 150B is poured to complete the floor slab 150.

[0043] [Effect] Next, the operation of this embodiment will be described.

[0044] In the foundation structure 100 of this embodiment, the L-shaped precast concrete member 140 has a first gap 102 and a second gap 104 formed between the upper surface 122 of the footing portion 120 of the foundation portion 110 and the side surface 132 of the rising portion 131, respectively. Then, concrete is poured onto the precast concrete member 140 as part of the formwork to construct the floor slab 150.

[0045] Therefore, a first gap 102 and a second gap 104 are formed between the floor slab 150 and the upper surface 122 of the footing portion 120 and the side surface 132 of the rising portion 131 of the foundation 110, respectively, and the two are almost completely separated. In other words, in the foundation structure 100 where the slab end 152 of the floor slab 150 cantileveres over the upper surface 122 of the footing portion 120 of the foundation 110, both the vertical and horizontal lines between the floor slab 150 and the foundation 110 are separated.

[0046] Therefore, compared to the case where only the vertical line is isolated, vibrations transmitted to the floor slab 150 via the foundation 110, especially micro-vibrations, are reduced.

[0047] Here, an insulating material 103 is provided in the second gap 104. However, the load from the slab end 152 of the floor slab 150 does not act on the upper surface 122 of the footing portion 120 via the insulating material 103. Therefore, the horizontal line is also isolated.

[0048] Next, we will explain that by using the construction method of the foundation structure 100 of this embodiment, the load on the slab end 152 of the floor slab 150 does not act on the upper surface 122 of the footing portion 120 via the insulating material 103.

[0049] Initially, the lower end 352 of the threaded reinforcing bar 350, which is attached to the mounting member 300 provided on the L-shaped precast concrete member 140, protrudes from the hole 143 in the first plate portion 142 and abuts against the upper surface 122 of the footing portion 120. Therefore, the load of the precast concrete member 140 is acted upon the upper surface 122 of the footing portion 120 via the threaded reinforcing bar 350.

[0050] Next, in this state, concrete is poured onto the precast concrete member 140 as part of the formwork to construct the floor slab 150. At this time, the load on the slab end 152 of the floor slab 150 is applied to the upper surface 122 of the footing portion 120 via the threaded reinforcing bars 350.

[0051] Then, after the concrete of the floor slab 150 has hardened, the threaded reinforcing bars 350 are removed from the mounting member 300, so that the load on the slab end 152 of the floor slab 150 is no longer acting on the upper surface 122 of the footing 120, thus creating a separation.

[0052] Furthermore, the threaded reinforcing bar 350 is attached to the mounting member 300 until the concrete hardens. Therefore, the steel pipe 302 of the mounting member 300 functions as a buckling prevention member for the threaded reinforcing bar 350.

[0053] Furthermore, by inserting the support member through the pre-formed hole 143 in the first plate portion 142 of the precast concrete member 140, the support member can be easily brought into contact with the upper surface 122 of the footing portion 120.

[0054] <Other> Furthermore, the present invention is not limited to the embodiments described above.

[0055] In the above embodiment, the lower end 352 of the threaded reinforcing bar 350, which is attached to the mounting member 300 provided on the precast concrete member 140, is made to protrude from the hole 143 in the first plate portion 142 and abut against the upper surface 122 of the footing portion 120, but it is not limited to this. Any mechanism or method is acceptable in which a support member that penetrates the precast concrete member 140 is abutted against the upper surface 122 of the footing portion 120 until the concrete of the floor slab 150 hardens, and the support member is removed after the concrete hardens.

[0056] For example, a support member such as a reinforcing bar, which is passed through the precast concrete member 140, is brought into contact with the upper surface 122 of the footing portion 120, and the floor slab is constructed by preventing concrete from entering around the support member with formwork or the like. After the concrete hardens, the support member and formwork are removed, and concrete is poured into the holes where the formwork was in the floor slab to fill them.

[0057] Alternatively, for example, the end portion 141 of the first plate portion 142 of the precast concrete member 140 may be firmly fixed to the ground improvement portion 250 on the floor slab side with anchors or the like. In this case, a support member that penetrates the precast concrete member 140 is not necessary.

[0058] Furthermore, in the above embodiment, for example, the foundation 110 and the floor slab 150 were constructed on top of the ground improvement body 200, but the invention is not limited to this. For example, the foundation 110 may be supported by piles constructed in the ground.

[0059] Furthermore, although an insulating material 103 was provided in the first gap 102 in the above embodiment, the invention is not limited to this, and the insulating material 103 may not be provided.

[0060] Furthermore, the present invention can be implemented in various forms without departing from the spirit of the invention. [Explanation of Symbols]

[0061] 100 Basic structure 102 First gap 104 Second gap 110 Foundation 120 Footing section 122 Top 131 Vertical section 132 Side view 140 Precast concrete members 142 First plate part 143 holes 144 Second plate part 150 floor slab 152 Slab end 200 Ground Improvement Units 350 Threaded reinforcing bars (an example of a support member)

Claims

1. A foundation having a footing section constructed on the ground and a rising section that rises from the footing section, A gap is formed between the upper surface of the footing portion and the side surface of the rising portion, and an L-shaped precast concrete member extends from the upper surface of the footing portion onto the ground, The aforementioned precast concrete members are constructed by pouring concrete onto the ground as part of the formwork, and a floor slab extends above the upper surface of the footing section, A foundation structure equipped with these features.

2. A step of constructing a foundation on the ground, having a footing and a rising section that rises from the footing, The process of installing the precast concrete member on the ground is as follows: a support member is attached by passing it through the L-shaped precast concrete member and brought into contact with the upper surface of the footing portion, and a gap is formed between the upper surface of the footing portion and the side surface of the rising portion; The process involves pouring concrete onto the aforementioned precast concrete members as part of the formwork to construct a floor slab, After the concrete of the floor slab has hardened, the process of removing the support member is performed. The process of pouring concrete onto the aforementioned floor slab, A construction method for a foundation structure that includes [a specific feature / feature].

3. The aforementioned precast concrete member has holes formed in it. The support member is attached by inserting it through the hole. A method for constructing the foundation structure described in claim 2.

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