JPH1018304A - Mat foundation structure and its construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly precisely and easily form a mat foundation for a prefabricated housing without the need for deep excavation and integrally form steel beams and concretes to obtain highly rigid composite beams. SOLUTION: Foundation work is applied on a ground surface constituting a mat foundation corresponding to the strength and nature of the ground, self- leveling material 22 is placed into the ground surface to form a horizontal reference plane 23 and a PC sill plate A is arranged on the reference plane 23 to fix poles B. The upper face levels of the poles B are adjusted to connect the poles B together with a girder C. A lower end bar 8b is arranged at the lower side of the girder C and the previously bent end of an upper end bar 8a is inserted into a hole 9 provided in the lower flange 7a of the beam C to form an embedded reinforcing bar E. Concrete 25 is placed to embed parts of the lower flange 7a and the web 7c of the girder C in a plane defined by a form 24. An upper building body is built up on the poles B, the girder C and beams before the concrete 25 is placed, thus to shorten a construction period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foundation structure of a prefabricated house and a construction method thereof, and more particularly to a foundation structure capable of integrating steel beams and concrete and a construction method thereof.

[0002]

2. Description of the Related Art A solid foundation structure is sometimes used as a foundation structure of a prefabricated house. Among them, Japanese Patent Laid-Open No.
There is a technique disclosed in Japanese Patent No. 9529. This technology relates to a solid foundation using a steel frame, and a foundation beam is configured as a steel-framed reinforced concrete structure (SRC structure) made of steel beams, reinforcing bars, and concrete.
A large number of mounting holes are formed in the web of the shaped steel, and the ends of the threaded rebar are inserted into the mounting holes, and the nuts are screwed and fixed. This foundation beam is installed so as to be embedded in the ground surface, and a steel beam is connected to a steel beam to form a foundation. This technique is advantageous because the positional accuracy of the anchor bolt can be improved.

[0003] On the other hand, there is a case where a floor slab is formed by casting concrete on an upper part of a floor beam. In this case, as shown in FIG. 8, studs 52 are welded to the upper flange 51a of the floor beam 51 made of H-section steel at a predetermined pitch, and stress is transmitted by the adhesive force of the concrete 53 to the stud 52 to transmit the stress. It is configured to increase the rigidity of 51. In this way, a steel beam and a floor slab integrated with each other to add the rigidity of the floor slab to the evaluation of the rigidity of the steel beam may be referred to as a composite beam.

[0004]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 3-199529.
In the technique disclosed in Japanese Patent Laid-Open No. H10-207, a steel beam is directly connected to a steel beam. For this reason, any one of the beams arranged orthogonally fits in the win, and there is a possibility that the variation in the length of the beams increases. In addition, the position accuracy of the anchor bolt is improved compared to the RC foundation, but in order to secure the level accuracy in the height direction or the accuracy in the horizontal direction, after joining the beams, the joined beams are lifted. There is a possibility that there is a problem that it is not an easy task to sandwich the spacer or adjust the position.

In addition, since the foundation beam is buried below the ground surface, concrete and steel bars are required to excavate the ground deeply and cover the steel beam, which takes a period of time required for rebar arrangement work and concrete placing work. There may be a problem that the cost may increase, or a problem that the construction period of the upper structural body is performed after the concrete is cast and the construction period is prolonged.

In particular, since the ends of the reinforcing bars are inserted into a large number of mounting holes formed in the web of steel beams and fixed by nuts, the work of threading each reinforcing bar and the nuts on each reinforcing bar are required. There is a problem that it takes time and effort to screw together.
Further, the method of directly applying a force in a direction perpendicular to the web surface on the web of the steel beam is not the original usage of the shaped steel, and has a problem of poor strength. .

The applicant of the present application has developed a solid foundation structure that solves the above-mentioned problems and a construction method thereof, and has already applied for a patent (Japanese Patent Application No. 7-1089). In this technique, since a pole is interposed when connecting a steel beam, the length of the steel beam is all the internal dimension between the poles, and variations in length can be reduced.

[0008] However, when concrete is cast on the ground surface surrounded by steel beams on the outer periphery of the building, means for integrating the cast concrete and the steel beams is not disclosed. There is a point to be.

When the stud is welded to the flange of the steel beam as in the prior art when the steel beam and the concrete in the solid foundation are integrated, quality control is important for the welding operation, and welding skills are required. A qualified person needs to carry out the work. Therefore, it is necessary to strictly control the process in order to secure welding technicians. Considering the transportation of steel beams, it is preferable to perform stud welding on site. However, at the stage of foundation work, the welding operation may be affected by the weather, which may cause problems in process management and quality control.

[0010] An object of the present invention is to further develop the above-mentioned invention by integrating a steel beam and concrete, and to achieve a solid foundation structure that can be constructed with good work accuracy and a small number of parts by easy work. It is an object of the present invention to provide a construction method in which the length is shortened.

[0011]

In order to solve the above problems, a solid foundation structure according to the present invention comprises a pole installed on a ground surface constituting a foundation, a steel beam connecting the poles, and a building. Made of concrete cast on the ground surface surrounded by steel beams on the outer periphery of the steel beam, and the end of the buried reinforcing bar is bent and inserted into a hole provided in the lower flange of the steel beam. It is characterized by the following.

In the solid foundation structure described above, a ground surface is excavated, and a plurality of poles are installed at predetermined intervals with respect to the ground surface by rolling the excavated ground surface, and the poles are connected by steel beams. It is also constructed by casting concrete on the outer periphery of the building and on the ground surface surrounded by steel beams. In particular, by bending and inserting the end of the buried reinforcing bar into the hole provided in the lower flange of the steel beam, the steel beam and concrete can be integrated through the buried reinforcing bar to form a composite beam. For this reason, a solid foundation having high rigidity (hereinafter simply referred to as “foundation”) can be configured by a simple operation that does not require a welding operation. In particular, in the solid foundation structure described above, it is preferable that the holes provided in the lower flange of the steel beam have a preset pitch.

In the above basic structure, a self-leveling material is cast on a ground surface on which a pole is to be installed to form a horizontal reference surface, and a precast concrete base plate is installed on the reference surface, and It is preferable to install a pole.

In the above-mentioned foundation structure, a self-leveling material is cast on the ground surface constituting the foundation to form the surface as a horizontal reference surface, and a precast concrete base plate (PC base plate) is formed on the reference surface. When the pole is installed on the PC base plate, the horizontality of the reference plane can be guaranteed, and the level of the pole can be easily guaranteed.

The pole is only fixed to the PC base plate and is not connected to the ground surface. For this reason, it is possible to move the pole in the horizontal direction on the reference plane on which the self-leveling material is cast together with the PC base plate,
If it is necessary to adjust the horizontal position of the pole when connecting the steel beam to the pole, the PC base plate can be easily moved and installed at an accurate position.

[0016] Further, a method for constructing a foundation structure according to the present invention comprises:
A pole is installed on the ground surface constituting the foundation, the poles are connected by a steel beam, the upper structural body is installed on the pole or the steel beam, and a hole provided in a lower flange of the steel beam is provided. Insert the bent end and place the rebar,
It is characterized in that concrete is cast on the ground surface surrounded by steel beams on the outer periphery of the building to form a solid foundation.

In the above construction method, the upper structure skeleton is installed on a pole installed on the ground surface constituting the foundation or a steel beam connecting the poles, and concrete is placed on the ground surface surrounded by the steel beam. It is possible to advance the construction method of the superstructure body at the same time or simultaneously with the construction of the superstructure body, thereby shortening the construction period.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the above-mentioned foundation structure and construction method will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a main part illustrating a foundation structure, FIG. 2 is a perspective view illustrating a reinforcing arrangement of the foundation structure according to the present embodiment, FIG. 3 is a schematic diagram illustrating a relationship between a steel beam and a foundation bar, FIG. 4 is a diagram illustrating a pole installed on the ground surface, FIG. 5 is a foundation plan, FIG. 6 is a diagram illustrating an example of another pole, and FIG. 7 is a diagram illustrating still another example of a pole. .

In the foundation structure according to the present invention, a PC base plate A is installed at a plurality of predetermined positions according to the upper building as shown in a base plan of FIG. And a steel beam C between adjacent poles B
After the bent end of the buried reinforcing bar E is inserted into the hole formed in the lower flange of the girder C, the girder C in the plane defined by the PC base plate A, the pole B, and the girder C It is constructed by casting concrete to a height including the lower flange and a part of the web.

The PC base plate A is made of precast concrete, and has a bottom plate 1 having a predetermined size and a mounting portion 2 on which a pole B is mounted. A plurality of reinforcing bars 1a are arranged on the bottom plate 1, and a plurality of insert nuts for fastening bolts 3 when the pole B is fixed are embedded in the mounting portion 2 at a predetermined pitch.

As a base plate on which the pole B is installed,
The PC base plate A is not necessarily required to be the PC base plate A formed of the precast concrete shown in the present embodiment, and may be formed using a steel plate or a shape steel.

The pole B of this embodiment is formed by using a flat bar made of a rolled steel plate, has a height equal to the height of the girder C set corresponding to the upper building, and is formed at the lower end. Is provided with a flange 4a connected to the mounting portion 2 of the PC base plate A, and a flange 4b is provided at an upper end for connecting a frame of an upper building. Flange 4
A plurality of webs 5 connecting the girders C are provided in the orthogonal direction between a and 4b. A plurality of bolt holes 6 are formed at predetermined positions of the flanges 4a, 4b and the web 5.

The girder C is made of H-shaped steel having a height preset according to design conditions such as the weight and floor area of the upper building. In the lower flange 7a of the girder C, holes 9 for inserting bent ends of the upper reinforcing bar 8a constituting the buried reinforcing bar E are formed at a predetermined pitch. Similarly, studs (not shown) are formed in the upper flange 7b and the web 7c. A plurality of bolt holes 10 are formed corresponding to the connection positions of the small beams D shown in FIG.

A connecting member 11 for connecting to the pole B is attached to the end of the girder C. This connection member
11 is formed in an L-shape including a joining piece 11a joined to the girder C and a joining piece 11b having a bolt hole and joining to the pole B, and is joined to the girder C via the joining piece 11a in advance. The joining piece 11b is brought into contact with the web 5 of the pole B so that the joining piece 11b
The bolts 12a are inserted into the bolt holes 6 of the poles B and the bolt holes 6a of the poles B, and the nuts 12b are fastened.

Next, a description will be given of the foundation structure and the construction procedure constituted by the members A to C.

First, the installation position of the PC base plate A is excavated in accordance with the foundation plan to perform the ground work 21 (see FIG. 4). The local business
21: Rolling of a specified part, laying of crushed stone after rolling, digging of a predetermined part, crushing of crushed stone or laying of crushed stone after rolling, improvement of surface ground, crushing of crushed stone after rolling or laying of pile, , Compaction or crushed stone laying after compaction, and these methods can be appropriately selected according to the strength and properties of the ground.

Therefore, if the condition of the ground is good and the strength is sufficient, only the compaction is sufficient. When excavating the ground, the excavation depth may be such that the upper surface of the bottom plate 1 of the PC base plate A is at the same level as the ground surface (about 150 mm). Thereafter, a self-leveling material 22 is cast at the installation position of the PC base plate A to form a horizontal reference surface 23.

Next, a PC base plate A for mounting the pole B on the reference surface 23 is installed. PC base plate A is pole B
Is installed where it should be installed. Then, the pole B is mounted on the mounting portion 2 of the predetermined PC base plate A, and fixed by the bolt 3. When the pole B is fixed to each PC base plate A, the PC base plate A is placed so that the level of the flange 4b of the pole B (the top end level of the pole B) coincides with a preset level. Part 2 and flange 4a of pole B
Spacers are appropriately arranged between the two. The top end level adjustment work can be performed by simply lifting the pole B and interposing a spacer between the pole B and the mounting portion 2 of the PC base plate A, and the work is easy.

In the above state, the pole B is placed on the ground surface via the PC base plate A, and a horizontal force is applied to the PC base plate A on which the pole B is mounted, so that the reference It is possible to move on the surface 23 in a desired direction.

Next, the girder C is connected between the poles B installed adjacent to each other. The connection of girder C to pole B is
This is performed via the joining member 11 attached to the end. That is,
The joining member 11 previously attached to the end of the girder C is brought into contact with the web 5 of the pole B, and the bolts 12a and the nuts 12b are temporarily tightened to connect the poles B with the girder C. After connecting the girder C and the pole B, the girder D is connected to a predetermined position of the girder C.

When the horizontal position of the pole B is displaced from a reference line (not shown) when the poles B are connected by the girder C, this positional deviation is caused by the connection of the girder C to the PC base plate A and the pole B. Is adjusted by moving in the horizontal direction. Then, after all the poles B have been adjusted to the preset installation positions, the bolts 12a and the nuts 12b are fully tightened.

After the poles B are connected by the large beams C as described above, the small beams D are connected so that the upper flange of the small beams D is at the same level as the upper flange 7b of the large beams C. . Thereafter, the upper skeleton is built on the poles B, the girders C, and the small beams D. That is, the skeleton columns are attached on the upper flanges of the poles B, girders C, and the small beams D, and the upper floor beams and the seismic resistance are sequentially mounted. Attach elements.

The reinforcing bars E are laid out in parallel with the building. In this arrangement, a plurality of lower streaks 8b are arranged in a lattice at a predetermined pitch through a lower side of the lower flange 7a of the girder C, and a plurality of upper streaks 8a are arranged on the upper side of the flange 7a. Are arranged in the upper end muscles 8
This is performed by inserting the bent end of a into the hole 9 formed in the lower flange 7a of the girder C (see FIG. 2).

When arranging the upper reinforcing bar 8a constituting the buried reinforcing bar E, holes 9 are formed in the lower flange 7a of the large beam C at a predetermined pitch in advance, so that the bent ends are inserted into the holes 9. It is possible to set the arrangement pitch of the upper streaks 8a, and it is possible to omit an inking operation for arranging the upper streaks 8a.

After the reinforcing bars E are laid out, the formwork 24 is attached to the outer periphery of the building (see FIG. 1). Formwork around the foundation
After stipulating by 24, concrete inside the formwork 24
Place 25. At this time, the concrete 25 is pressed to a depth that covers the lower flange 7a of the girder C and a predetermined lower portion of the web 7c and does not cover the small girder D that is smaller than the girder C. Is established. Then, when the poured concrete 25 has hardened, the target foundation is constructed.

In the above basic structure, the lower flange 7 of the girders C
The lower flange 7a is inserted in a state in which the bent end of the upper reinforcing bar 8a constituting the embedded reinforcing bar E is inserted into the hole 9 formed in the lower flange 7a.
The concrete 25 and the girder C are firmly integrated with each other via the upper reinforcing bar 8a (buried reinforcing bar E) by being cast into a depth covering a predetermined lower portion of the web 7b, thereby forming a steel beam. The girder C can be evaluated as a composite beam, and a foundation having high rigidity can be formed. For this reason, the buckling of the girder C can be restrained by the hardened concrete, and the cross-sectional performance of the girder C can be reduced to reduce the weight.

In addition, it is possible to precede the construction of the upper structure before casting the concrete, which is compared with the conventional method of constructing the foundation by placing concrete and then constructing the upper structure. Thus, it is possible to shorten the construction period required for the reinforcing work, concrete placing work, and curing.

In the above-described embodiment, a case has been described in which a plate cut from a rolled steel plate or a steel pole made of a standard flat bar is used as the pole B. However, the pole B only needs to have a function of connecting the girder C, and is not limited to steel.

FIG. 6 shows a PC made of precast concrete.
FIG. 3 is a perspective view illustrating a configuration of a pole 31. The PC pole 31 is formed in a rectangular rod shape having a length greater than the height of the girder C. The PC base plate 32 has the same basic configuration as that of the PC base plate A described above, except that a concave portion 32a into which the lower end portion 31a of the PC pole 31 is fitted instead of the mounting portion 2 is formed. A plurality of column base anchor bolts 33 are embedded at a predetermined pitch in the upper end surface 31b of the PC pole 31, and a plurality of insert nuts are embedded at a predetermined pitch in each side surface 31c. Is formed.

Even when the PC pole 31 configured as described above is used as the pole B, the lower end 31a is fitted into the recess 32a of the PC base plate 32 to adjust the level, and
The girder C can be connected to the adjusted PC pole 31.

FIG. 7 is a perspective view for explaining the structure of a cast steel pole 35 made of cast steel. The cast steel pole 35 is formed in a shape in which one end of a square tube is closed by a lid, and an opening 35a is formed at a lower end portion, as shown in FIG. That is, the outer shape of the cast steel pole 34 is formed in the shape of a square bar like the PC pole 31. Further, as shown in FIG. 3A, a tap hole 37 for fastening a bolt 36 for fixing a column base is formed in an upper end surface 35b of the cast steel pole 35, and a bolt 36 for fixing a girder C is formed on each surface 35c. Multiple tap holes to fasten
37 are formed at the same pitch as the PC pole 31.

The length of the cast steel pole 35 is not particularly limited. For example, when the cast steel pole 35 is formed to have the same length as the PC pole 31, a PC base plate for the pole 31 is used.
It is possible to use 32. However, it is preferable to reduce the length of the cast steel pole 35 in order to reduce the manufacturing cost. In this case, the opening 35 of the cast steel pole 35
It is preferable to use a PC base plate 38 formed with a projection 38a that fits into a.

Even with the cast steel pole 35 configured as described above, it is possible to configure the same basic structure as the pole B described above.

Further, in the above-described method for constructing the foundation, after the concrete 25 is cast, the formwork 24 does not have to be removed when the concrete 25 hardens. Therefore, the ALC which constitutes the floor of the first floor during the curing period of the poured concrete
It is also possible to lay panels such as panels, thereby shortening the entire construction period.

It is also possible to build the upper frame after the concrete 25 is cast. In this case, however, the curing of the concrete is performed in comparison with the case where the upper frame is built before the concrete is cast. Only in the period corresponding to the period, the number of days for shortening the construction period is reduced.

[0046]

As explained in detail above, in the foundation structure according to the present invention, a pole is interposed when connecting steel beams,
In addition, since the end of the buried reinforcing bar is bent and inserted into the hole provided in the lower flange of the steel beam, and then concrete is poured, the connection work between the steel beam and the pole is easy, and the structure of the steel beam. In particular, the length is unified to the distance between the poles, the variation in length can be reduced, and the composite beam can be formed by firmly integrating the steel beam and concrete. Therefore, a foundation having high rigidity can be constructed without increasing the number of parts.

The function as a conventional stud can be exhibited by the buried reinforcing bar passed through the hole provided in the lower flange of the steel beam. Therefore, a composite beam having high rigidity can be formed without performing welding work. In particular, since welding work is not required, even a worker who does not hold the welding qualification can proceed and can carry out the work without being affected by the weather. Therefore, the accuracy of the process control can be improved.

In arranging the reinforcing bars, holes are formed in the lower flange of the steel beam at a predetermined pitch in advance. By inserting the bent ends of the reinforcing bars into the holes, the arrangement pitch of the reinforcing bars is increased. Can be set, and the inking work for arranging the buried reinforcing bars can be omitted.
In addition, the rebar arrangement work can be performed extremely easily as compared with the case where the nut is screwed and fixed.

When connecting the poles with steel beams, a self-leveling material is cast on the ground surface on which the poles are installed to form a horizontal reference plane. Since the pole can be easily secured and the pole can be moved in the horizontal direction, the positional accuracy in the horizontal direction can be easily secured. For this reason, it is possible to construct a high-precision foundation, and it is possible to greatly improve the accuracy of the construction of the upper structural body, thereby improving the accuracy of the first floor level.

Since there is no need to excavate the ground deeply,
Remaining soil treatment is reduced, and the construction period can be shortened and costs can be reduced.

After the concrete has been cast, 1
By laying floor plates on the floor, it is possible to provide a space for the construction of the upper part, and it is possible to improve workability and safety.

The steel beam constituting the foundation can be used for the upper structure of the second floor or more. Therefore, the number of types of parts can be reduced, and the method of fixing the floor plate on the first floor can be shared with the method of fixing the floor plate on the second floor or more.

When the lower flange and a part of the web are covered with concrete and the buried reinforcing bar whose end is inserted into the hole of the lower flange is integrated, the reinforcing bar is fixed to the web. In comparison, steel beams and concrete are strongly integrated, improving the performance of transmitting bending stress between steel beams and concrete slabs and increasing rigidity to reduce buckling of steel beams. The beam can be restrained, and the cross-sectional performance of the beam can be reduced synergistically to reduce the weight.

Further, since the entire steel beam is not covered with concrete, the amount of concrete to be cast can be reduced. In this case, fixing the reinforcing bar to the lower flange rather than fixing the reinforcing bar to the web of the steel beam enables the beam to be concretely integrated with the concrete.

Further, in the construction method according to the present invention, when concrete is cast after the upper frame is installed on the pole or the steel beam, the method of building the upper frame can be advanced in advance. This makes it possible to shorten the construction period and has other features.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part for explaining a basic structure.

FIG. 2 is a perspective view illustrating a reinforcement arrangement state of the foundation structure according to the embodiment.

FIG. 3 is a schematic diagram illustrating a relationship between a steel beam and a foundation reinforcing bar.

FIG. 4 is a diagram illustrating a pole installed on the ground surface.

FIG. 5 is a basic plan view.

FIG. 6 is a diagram illustrating an example of another pole.

FIG. 7 is a diagram illustrating still another example of a pole.

FIG. 8 is a diagram illustrating an example of a conventional composite beam.

[Explanation of symbols]

 A PC base plate B Pole C Large beam D Small beam E Buried reinforcing bar 1 Bottom plate 1a Reinforcing bar 2 Placement part 3 Bolt 4a Lower flange 4b Upper flange 5 Web 6 Bolt hole 7a Lower flange 7b Upper flange 7c Web 8a Upper bar 8b Lower bar 9 Hole 11 Connection member 11a, 11b Joint piece 11c Bolt hole 12a Bolt 12b Nut 21 Ground work 22 Self-leveling material 23 Reference surface 24 Formwork 25 Concrete 31 PC pole 32, 38 PC base plate 35 Cast steel pole

Claims (4)

[Claims] 1. A pole installed on a ground surface constituting a foundation, a steel beam connecting between the poles, and concrete cast on a ground surface surrounded by steel beams on the outer periphery of the building. Wherein the end of a buried reinforcing bar is bent and inserted into a hole provided in a lower flange of the steel beam. 2. The solid foundation structure according to claim 1, wherein the holes provided in the lower flange of the steel beam have a preset pitch. 3. A horizontal reference surface is formed by casting self-leveling material on the ground surface on which the pole is to be installed, a precast concrete base plate is installed on the reference surface, and the pole is installed thereon. The solid foundation structure according to claim 1 or 2, wherein: 4. A pole is installed on the ground surface constituting the foundation, the poles are connected by a steel beam, an upper structural body is installed on the pole or the steel beam, and a lower flange is provided on the lower flange of the steel beam. Inserting the bent end into the hole provided, arranging rebar, and placing concrete on the ground surface surrounded by steel beams on the outer periphery of the building to constitute a solid foundation Foundation construction method.