JP2006144490A - Foundation structure of building and its construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To largely improve workability in the foundation structure of a building allowing uplift of the superstructure of the building. <P>SOLUTION: A foundation 10 including a pile 12 and a footing 14 is provided with a fitting protrusion 18 on an upper surface of a pile head and a fitting recess 20 in a lower surface of the footing. A relative displacement of the pile and the footing in a horizontal direction is hindered by fitting the fitting protrusion 18 to the fitting recess 20. The footing can lift up from the pile head as the fitting recess and the fitting protrusion move apart from each other. A fitting protrusion forming member 22 is made of precast concrete (PC), and a preceding cast part 42 of a cast-in-place concrete pile 12 is laid. The fitting protrusion forming member 22 made of PC is arranged on the upper surface of the preceding-cast part by the intermediary of a spacer 44. A following-cast concrete part of the pile 12 is laid to construct the pile 12. By using the pile head of the finished pile 12 as a part of a form, the footing 14 made of the cast-in-place concrete is laid. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a building basic structure and a construction method thereof. More particularly, the present invention relates to a building basic structure and a method for constructing the same, which allow the building superstructure to be lifted to reduce the energy received by the building when an earthquake occurs.

  If a horizontal acceleration is applied to the foundation of the building when an earthquake occurs, a falling moment will act on the building. When the acceleration in the horizontal direction is large and the aspect ratio of the building (the ratio of height to width) is also large, one side of the building tends to rise due to the overturning moment. As a result, in the case of a building that employs a pile foundation, for example, a tensile load for pulling out the pile acts on the pile on the floating side of the building, and a compressive load for pushing the pile increases on the opposite side. In order to construct a foundation structure with sufficient strength to withstand these loads, a corresponding cost is required, but in recent years, high-rise buildings with large aspect ratios have emerged one after another. Therefore, the increase in the cost was remarkable.

  Therefore, the foundation structure of the building is proposed in which the footing that is fixedly connected to the pile head is cut off from the pile head, and when a large overturning moment acts, the upper structure of the building above the footing is lifted from the pile head. Has been.

  For example, Japanese Unexamined Patent Application Publication No. 2003-129498 discloses a building basic structure in which the edge between a pile and a footing is cut by joining the pile and the footing via a steel pipe for shear resistance. In this foundation structure, a cushioning material is laid between the pile and the footing in order to mitigate the impact when the raised upper structure of the building is seated.

  Japanese Laid-Open Patent Publication No. 2000-240315 discloses a foundation structure of a building in which the column base is lifted to reduce the response of the building after it is lifted by the energy absorbing device. Then, a cushioning material for mitigating the impact at the time of sitting and a restoring member for controlling the displacement are interposed in the raised portion.

Japanese Patent Laid-Open No. 2001-115683 discloses a structure in which a damper is interposed in a gap between a steel pipe column of a building upper structure and a steel pipe embedded in a foundation footing that is a lower structure of the building.
JP 2000240315 A JP 2001-115683 A JP 2003-129498 A

  However, the basic structures that have been proposed in the prior art, including those disclosed in these patent documents, are forced to perform complicated and troublesome work to produce the raised portion. However, it was difficult to achieve high accuracy, which was accompanied by a difficulty related to workability. The method of using a precast concrete member (PC member) as the pile head part and footing that constitute the raised part is useful for simplifying on-site work. Therefore, transportation and installation work on the site will be difficult, and mortar grout will be applied to the narrow part of the joint between the pile head made of PC and the cast-in-place pile body. This is necessary and difficult. Furthermore, precise alignment is required between the pile head portions each configured as a PC member and the footing, but this alignment operation is not easy.

  The present invention has been made in view of such circumstances, and an object of the present invention is to greatly improve the workability of a building basic structure that allows the upper structure of the building to be lifted. .

  In order to achieve the above object, a building foundation structure according to the present invention is a building foundation structure including a pile and a footing supported by the pile, and a fitting convex portion is provided on the pile head upper surface of the pile. A fitting recess is provided on the lower surface of the footing, and the fitting protrusion and the fitting recess are fitted to prevent relative horizontal displacement between the pile and the footing. On the other hand, the foundation structure of the building in which the footing is lifted from the pile head of the pile by the separation of the fitting concave portion and the fitting convex portion when a falling moment of a predetermined size or more is applied to the building. The pile is constructed by joining a precast concrete (PC) member, which is a precast concrete (PC) member, which defines the fitting protrusion to a pile head of a cast-in-place concrete pile. And the footing is It is a cast-in-place concrete footing, and the fitting recess is defined on the lower surface of the footing by being placed using the pile head of the completed pile as a part of the formwork. Features.

  Further, the building foundation construction method according to the present invention is a building foundation comprising a pile and a footing supported by the pile, and a fitting convex portion is provided on the pile head upper surface of the pile, While a fitting recess is provided on the lower surface of the footing and the fitting protrusion and the fitting recess are fitted, relative horizontal displacement between the pile and the footing is prevented. Construction of the foundation structure of the building in which the footing is lifted from the pile head of the pile by separating the fitting concave portion and the fitting convex portion when a falling moment of a predetermined size or more is applied to the building In the method, the pile having the fitting convex portion provided on the pile head is constructed, and thereafter, the pile head of the completed pile is used as a part of a formwork and a cast-in-place concrete footing is placed. Thus, the fitting recess is defined on the lower surface. Characterized by constructing the footing.

  According to the present invention, in a foundation structure that allows the superstructure of a building to be lifted, a pile having a fitting protrusion on the pile head is constructed first, and then the pile head of the completed pile is Since the cast-in-place concrete footing is used as the portion, the fitting recess and the bottom surface of the footing can be defined with high accuracy by an extremely easy operation. Therefore, the field work for constructing the foundation is greatly facilitated, the workability is greatly improved, and the dimensional accuracy of the fitting convex part and the fitting concave part is also improved.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional side view of a foundation 10 employing a building foundation structure according to a preferred embodiment of the present invention. As shown in FIG. 1, the foundation 10 is a so-called reinforced concrete pile foundation including a reinforced concrete pile 12 and a reinforced concrete footing 14 supported by the pile 12 (in FIG. 1, in FIG. 12 and reinforcing bars arranged in the footing 14 are not shown). However, unlike the normal pile foundation, the pile head and the footing are not fixedly connected, and the pile head of the pile 12 and the footing 14 are cut off. And the fitting convex part 18 is provided in the pile head upper surface of the pile 12, the fitting recessed part 20 is provided in the lower surface of the footing 14, and these fitting convex part 18 and the fitting recessed part 20 are fitting, The relative horizontal displacement between the pile 12 and the footing 14 is prevented. On the other hand, when a horizontal acceleration is applied to the building from the ground when an earthquake occurs, and a falling moment of a predetermined magnitude or more determined according to the design of the building acts on the building, it fits on the floating side of the building. The footing 14 is lifted from the pile head of the pile 12 by separating the convex portion 18 and the fitting concave portion 20. In the figure, the interposition between the fitting convex portion 18 and the fitting concave portion 20 is a plate-shaped cushioning material, the periphery of the fitting convex portion 18 on the bottom surface of the footing 14 and the pile head upper surface of the pile 12. It is the edge cutting sheet that is interposed between the two and will be described later.

  The shape of the fitting convex portion 18 and the fitting concave portion 20 can be any shape as long as the above-described horizontal displacement prevention function and floating allowance function can be obtained, but can be adopted. Among these various shapes, it is particularly preferable to have a truncated cone shape or a truncated pyramid shape with the axis oriented in the vertical direction. Moreover, in order to implement | achieve the foundation which functions favorably, it is desired to define the fitting convex part 18 and the fitting recessed part 20 with high precision. The work to define the frusto-conical or pyramid-shaped convex part or concave part with high accuracy in reinforced concrete construction is very difficult with the conventional method using the formwork, but the work is extremely difficult by using the present invention. It can be easily implemented.

  FIG. 2 is a diagram showing a specific example of a precast concrete (PC) member used for constructing the foundation 10 of FIG. 1, wherein A is a plan view of the first specific example, and B is the same side surface. FIG. C is a plan view of the second specific example, D is a side view thereof, E is a cross-sectional view of the first and second specific examples, and F is a cross-sectional view illustrating a modified example of the first and second specific examples. FIG. Since the PC member shown in FIG. 2 is a member that defines the fitting convex portion 18, these are hereinafter referred to as a PC-made fitting convex portion defining member.

  The PC fitting projection defining member 22 according to the first specific example shown in FIGS. 2A and 2B has the fitting projection 18 and the fitting recess 20 shaped in the vertical direction. This is used when the shape is an octagonal frustum. The PC fitting convex portion defining member 22 includes a fitting convex portion defining portion 28 that is an upper portion and a base portion 30 that is a lower portion. A plurality of reinforcing bars 32 extend from the lower surface of the base portion 30, and these reinforcing bars 32 extend radially downward after extending downward. The fitting convex portion defining portion 28 has an octagonal truncated pyramid shape with the axis oriented in the vertical direction, and the base portion 30 has an octagonal prism shape with the axis oriented in the vertical direction.

  The PC-made fitting convex portion defining member 24 according to the second specific example shown in C and D of FIG. 2 has the fitting convex portion 18 and the fitting concave portion 20 shaped in the vertical direction. This is used in the case of a truncated cone shape. The difference from the PC-made fitting projection defining member 22 according to the first specific example is that the fitting projection defining portion 34, which is the upper portion, has a truncated cone shape whose axis is oriented in the vertical direction. The base portion 36, which is the lower portion, has a cylindrical shape with the axis oriented in the vertical direction. The other points are the same as those of the PC fitting convex portion defining member 22 according to the first specific example, and a plurality of reinforcing bars 32 similarly extend from the lower surface of the root portion 36. The shape of the PC-made fitting convex portion defining member used in the present invention is determined according to the design shape of the fitting convex portion 18 and the fitting concave portion 20, and is limited to the shapes exemplified above. It is not a thing.

  E in FIG. 2 is a cross-sectional view showing the reinforcing bars 32 of the PC fitting convex defining members 22 and 24, and a plurality of reinforcing bars 32 are assembled to each other via three hoop bars. It is attached. The reinforcing bar 32 is not limited to that shown in E of FIG. For example, F in FIG. 2 shows a modified example of the PC fitting projection defining members 22, 24. As shown in this figure, the reinforcing bars 32 are made of PC fitting projection defining members 22, You may make it extend from 24 outer peripheral part vicinity. In this modified example, a plurality of reinforcing bars 32 arranged in a radial manner are assembled to each other via four hoop bars.

  Below, the specific example of the construction method of the foundation structure of the building which concerns on suitable embodiment of this invention is demonstrated with reference to FIGS. 3-9 which showed each step. In this case, when the PC fitting convex defining member 22 shown in FIGS. 2A and 2B is used, and the PC fitting convex defining member 22 shown in FIG. 2F is used. This will be explained in the case where it is done.

  In the method of this specific example, first, the PC fitting projection defining member 22 is manufactured in a factory and transported to the site. On the site, the pile 12 is constructed as a cast-in-place concrete pile. In that case, first, as shown in FIG. 3, the leading portion 42 of the cast-in-place concrete pile 12 having the pile main reinforcement 40 is placed. This leading portion 42 is a main body portion of the entire cast-in-place concrete pile 12 excluding the pile head, and the imaginary line in FIG. 3 shows the shape of the pile head when the pile 12 is completed. Is.

  Next, as shown in FIG. 4, a plurality of spacers 44 for supporting the PC fitting convex portion defining member 22 are arranged on the upper surface of the leading portion 42. At this time, if the top surface of the leading portion 42 is rough and the spacer 44 is difficult to settle down, the top surface of the leading portion 42 may be appropriately hung. The spacer 44 is more easily installed by supporting the reinforcing bar 32 than by supporting the bottom surface of the concrete portion of the PC fitting projection defining member 22. In that case, the arrangement of the spacers 44 is matched to the form of the reinforcing bars 32 of the PC fitting convex portion defining member 22. 4A shows the arrangement of the spacers 44 when the PC-made fitting convex portion defining member shown in FIGS. 2A and 2B is used, and FIG. 4B shows the PC shown in FIG. 2F. The arrangement of the spacers in the case of using the fitting fitting defining member is shown.

  Subsequently, as shown in FIG. 5, the PC fitting convex portion defining member 22 is installed on the upper surface of the leading portion 42 through the spacer 44. The installation position of the fitting projection defining member 22 made of PC needs to be adjusted to the target position with high accuracy. However, if the method of installing on the top surface of the leading portion 42 via the spacer 44 is used as described above, High accuracy can be achieved very easily. The spacer 44 is schematically shown as a triangle in FIGS. 4 and 5, but in actuality, a spacer having an appropriate shape that can be easily adjusted in height is used. A thin plate for adjustment may be used together. Further, the hoop bar 45 is fastened to the upper protruding part of the main pile bar 40 protruding from the leading portion 42 of the pile 12. FIG. 5 shows a state in which the above has been completed. A in FIG. 5 is a plan view of a pile head, and B in FIG. 5 is a PC-made fitting convex defining member shown in A and B of FIG. FIG. 4C is a cross-sectional side view of the pile head when the PC fitting convex defining member shown in F of FIG. 2 is used.

  Subsequently, a formwork (not shown) for defining the pile head is assembled, and the upper protruding portion of the pile main reinforcing bar 40 and the reinforcing bar 32 extending from the lower surface of the PC fitting convex defining member 22 Then, the post-placed portion 46 of the cast-in-place concrete pile 12 is placed and the formwork is removed so that the base root portion 30 which is the lower portion of the fitting fitting defining member 22 made of PC is covered with concrete. This completes the construction of the cast-in-place concrete pile 12. FIG. 6 shows a state in which the above is completed. FIG. 6A is a plan view of the pile head of the completed pile 12, and FIG. 6B is a PC fitting projection shown in A of FIG. The sectional side view of the pile head of the completed pile 12 when the part defining member 22 is used, FIG. 6C shows the PC fitting convex part defining member 22 according to the modified example shown in F of FIG. It is a cross-sectional side view of the pile head of the completed pile 12 when used.

  In addition, about creation of the fitting convex part 18, the reinforcing bar and the ready-made formwork which are arranged to the fitting convex part 18 are used on-site without using the PC fitting convex part defining member. Although it is possible to adopt a method in which the fitting convex portion 18 is integrally defined when the concrete of the trailing portion 46 is placed by placing it on the pile head of the striking portion 42, the fitting convex portion 18. It is preferable to use a PC-made fitting convex portion defining member in order to make the size and shape of the high-precision.

  If the pile 12 is completed in this way, then, as shown in FIG. 7, on the surface of the fitting convex portion 18 defined by the fitting convex portion defining portion of the PC fitting convex portion defining member, A plate-like cushioning material 48 made of a chlorobrene rubber plate or the like is attached using an adhesive or the like. The plate-like cushioning material 48 is for absorbing an impact when the footing 14 that has lifted from the pile head at the time of the earthquake is seated again. Moreover, the edge cutting sheet 50, such as vinyl with which peeling of concrete is easy, is stuck on the upper surface of the pile head of the pile 12 around the fitting convex part 18. The plate-like cushioning material 48 also has a function as an edge cutting sheet because the concrete is easily peeled off when concrete is placed on the surface thereof. Moreover, as an example of a change in the above configuration, instead of adhering the edge cutting sheet 50 to the upper surface of the pile head of the pile 12 around the fitting convex portion 18, a plate-like cushioning material is also adhered there. May be.

  Further, the caulking material 51 is filled in the gap between the plate-shaped cushioning material 48 adhered to the top of the fitting convex portion 18 and the plate-shaped cushioning material 48 adhered to the slope portion of the fitting convex portion 18. The caulking material 51 is also filled in the gap between the plate-like cushioning material 48 and the edge cutting sheet 50 attached to the slope portion of the joint projection 18. The caulking material to be used is one that adheres strongly to the plate-like cushioning material 48 and the edge-cut sheet 50 at the time of filling, and that when the concrete is cast on the surface after curing, the concrete is easily peeled off.

  Next, as shown in FIG. 8, the reinforcing bar assembly 54 on the lower surface side of the footing 14 is installed on the pile head of the pile 12 through the spacer 52. This reinforcing bar assembly 54 includes a portion in which reinforcing bars are assembled in a lattice shape corresponding to the bottom surface of the footing 14 and a portion in which reinforcing bars are radially assembled corresponding to the fitting recesses 20, and is assembled in advance at a factory or the like. If things are transported to the site, work efficiency can be increased. 8A is a schematic diagram showing a reinforcing bar arrangement form of the reinforcing bar assembly 54. In FIG. 8, a dotted line around the reinforcing bar assembly 54 shows an outline of the footing 14 after completion. FIG. 8B is a partial cross-sectional side view of the pile head.

  Next, as shown in FIG. 9, the reinforcing bars 56 on the side surface side and the upper surface side of the footing 14 are fastened and fixed to the reinforcing bar assembly 54. Thereafter, a formwork (not shown) for defining the peripheral portion, side face, and top face of the pile 12 in the bottom face of the footing 14 is assembled, concrete is placed, and the formwork is removed, whereby FIG. The construction of the cast-in-place concrete footing 14 shown in FIG. According to this method, the pile 12 having the fitting protrusions 18 provided on the pile head is constructed first, and then the pile head of the completed pile 12 is used as a part of the formwork to make the cast-in-place concrete structure. Since the footing 14 is placed, the fitting recess 22 and the bottom surface of the footing 14 can be defined with high accuracy by an extremely easy operation.

  Moreover, according to the method which concerns on embodiment described above, since only the part of the fitting convex part 18 of a pile head is PC-ized as the fitting convex part definition member 22 made from PC, weight reduction of PC member In addition, the size and size can be reduced, transportation and installation work at the site are easy, and the position of the fitting convex portion 18 can be easily obtained with high accuracy. Furthermore, since the footing 14 is placed after the plate-like cushioning material 48 is attached to the fitting convex portion 18, the fitting between the plate-like cushioning material 48 and the fitting concave portion 20 of the footing 14 is good, and the fitting is performed. Since the stress due to the shearing load acting on the fitting convex portion 18 from the mating concave portion 20 is transmitted uniformly, a high resistance force against the gun or the horizontal direction acting on the footing 14 is obtained.

It is a section side view of the foundation which adopted the foundation structure of the building concerning a suitable embodiment of the present invention. It is the figure which showed the specific example of the precast concrete (PC) fitting convex part definition member used for the foundation of FIG. 1, A is a top view of the 1st specific example, B is the same side view, C is the 1st 2 is a plan view of the second example, D is the side view, E is a cross-sectional view of the first and second specific examples, and F is a cross-sectional view showing a modification of the first and second specific examples. It is a figure for demonstrating the construction method of the foundation structure of the building which concerns on suitable embodiment of this invention, and is a cross-sectional side view of a pile head. It is a figure for demonstrating the construction method of the foundation structure of the building which concerns on suitable embodiment of this invention, A and B are the cross-sectional side views of a pile head, respectively. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the construction method of the foundation structure of the building which concerns on suitable embodiment of this invention, A is a top view of a pile head, B, C is a cross-sectional side view of a pile head, respectively. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the construction method of the foundation structure of the building which concerns on suitable embodiment of this invention, A is a top view of a pile head, B, C is a cross-sectional side view of a pile head, respectively. It is a figure for demonstrating the construction method of the foundation structure of the building which concerns on suitable embodiment of this invention, and is a partial cross section side view of a pile head. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the construction method of the foundation structure of the building which concerns on suitable embodiment of this invention, A is the schematic diagram which showed the reinforcement arrangement | positioning form of a reinforcing bar assembly, B is a partial cross section side surface of a pile head FIG. It is a figure for demonstrating the construction method of the foundation structure of the building which concerns on suitable embodiment of this invention, and is a partial cross section side view of a pile head.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Foundation, 12 ... Cast-in-place concrete pile, 14 ... Footing, 18 ... Fitting convex part, 20 ... Fitting concave part, 22 ... PC fitting convex part definition member, 24 ... PC Mating convexity defining member made of 32, 32. Reinforcing bars of fitting convexity defining member made of PC, 40 ... Pile main bar, 42 ... Punched portion of pile, 44 ... Spacer, 46 ... After pile 48. Plated cushioning material, 50 ... Edge cutting sheet, 51 ... Caulking material, 52 ... Spacer, 54 ... Reinforcing bar assembly.

Claims (8)

A foundation structure of a building including a pile and a footing supported by the pile, wherein a fitting convex portion is provided on an upper surface of the pile head of the pile, a fitting concave portion is provided on a lower surface of the footing, and the fitting convexity is provided. When the horizontal displacement between the pile and the footing is prevented by fitting the part and the fitting concave part, while a falling moment of a predetermined size or more acts on the building In the foundation structure of the building in which the footing is lifted from the pile head of the pile by separating the fitting concave portion and the fitting convex portion,
The pile is constructed by joining a precast concrete (PC) member, which is a precast concrete (PC) member, that defines the fitting protrusion to a pile head of a cast-in-place concrete pile. And
The footing is a cast-in-place concrete footing, and the fitting recess is defined on the lower surface of the footing by being placed using the pile head of the completed pile as a part of the formwork. Yes,
The basic structure of the building.   The PC fitting convex part defining member includes a fitting convex part defining part which is an upper part and a base part which is a lower part, and a plurality of reinforcing bars extend from the lower surface of the base part. The building foundation structure according to claim 1, wherein:   The fitting convexity defining portion of the PC fitting convexity defining member has a shape of a truncated pyramid or a truncated cone with the axis oriented in the vertical direction, and the fitting convexity defining member made of PC 3. The foundation structure of a building according to claim 2, wherein the base portion has a shape of a prism or a cylinder having an axis oriented in a vertical direction.   The cast-in-place concrete pile has a precast concrete portion to be placed before the PC fitting convex part defining member is installed on the pile head, and the PC fitting convex part defining member is installed on the pile head. A post-cast concrete portion to be placed later, the post-cast concrete portion including the reinforcing bar extending from the lower surface of the PC fitting convex defining member, and the PC fitting convex defining member. The foundation structure of a building according to claim 2, wherein the base portion is included.   A plate-like cushioning material is stuck to the surface of the fitting convex portion, and an edge-cut sheet or a plate-like cushioning material is attached to the upper surface of the pile head of the pile around the fitting convex portion. The building foundation structure according to any one of claims 2 to 4, wherein the building foundation structure is provided. A foundation structure of a building including a pile and a footing supported by the pile, wherein a fitting convex portion is provided on an upper surface of the pile head of the pile, a fitting concave portion is provided on a lower surface of the footing, and the fitting convexity is provided. When the horizontal displacement between the pile and the footing is prevented by fitting the part and the fitting concave part, while a falling moment of a predetermined size or more acts on the building In the construction method of the foundation structure of the building in which the footing is lifted from the pile head of the pile by separating the fitting concave portion and the fitting convex portion,
By constructing the pile provided with the fitting convex portion on the pile head, and then, using the pile head of the completed pile as a part of the formwork, placing a cast-in-place concrete footing, Constructing the footing with the fitting recess defined on the lower surface;
A method for constructing the foundation structure of a building, characterized by that. When building the pile,
A member that defines the fitting convex portion, and a PC fitting convex portion defining member that is a precast concrete (PC) member in which a reinforcing bar extends from the lower surface,
Protruding the pile main reinforcement upwards and placing the cast-in part of cast-in-place concrete pile,
The PC-made fitting convex portion defining member is installed on the upper surface of the leading portion via a spacer,
The upper protruding portion of the pile main bar, the reinforcing bar extending from the lower surface of the PC fitting convex defining member, and the lower portion of the PC fitting convex defining member are wrapped with concrete. And placing the post-casting portion of the cast-in-place concrete pile to construct the pile,
The method for constructing a foundation structure of a building according to claim 6.   After the pile is completed, a plate-like cushioning material is stuck on the surface of the fitting convex portion, and the edge-cutting sheet or the plate on which the concrete can be easily peeled on the upper surface of the pile head around the fitting convex portion 8. The method for constructing a building foundation structure according to claim 7, wherein a cushioning material is attached, and then the cast-in-place concrete footing is placed.

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