JP5270112B2 - Wall structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wall-like structure manufacturable at low cost despite the fact that its structure is hard to cause cracking in a wall body part erected on a bottom board part. <P>SOLUTION: In this concrete wall-like structure formed by erecting the wall body part on the bottom board part, the bottom board part 1 having a projecting portion 2 projecting upward with a thickness equal to that of the wall body part is formed and an upper wall body portion 3 is formed by depositing concrete on the projecting portion 2. Therefore, the wall body part is formed of the projecting portion 2 and the upper wall body portion 3. Since a restriction by the bottom board part is reduced and a temperature stress produced is also reduced, cracking is suppressed more than in the case where the wall body part is erected by directly depositing concrete on the bottom board part. Since only the bottom board part having the projecting portion is formed, the wall-like structure can be constructed at low cost. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a concrete wall-like structure found in a general wall or a box culvert wall.

  Conventionally, this type of concrete wall-like structure is constructed by pouring concrete that becomes a wall body portion onto a bottom slab portion made of existing concrete such as a bottom plate or a floor board. In the wall-like structure constructed in this way, cracks are likely to occur in the wall portion standing on the bottom plate portion. The cause is considered to be because the volume change of the concrete due to the heat of hydration of the cement is restrained by the bottom slab part made of existing concrete. In many cases, such a crack generated in the wall portion extends upward from the vicinity of the bottom plate portion. In addition, once it occurs, its width increases, and there are many cases that are problematic from the appearance.

  As a general countermeasure conventionally taken against such cracks, the following can be cited. For example, material efforts such as using low heat cement or expansion material to reduce temperature stress are taken, or a method of concentrating cracks on the joints by placing crack-inducing joints on the wall is adopted. It is.

Japanese Patent Laid-Open No. 06-048790 JP 2001-220833 A

Among the measures described above, the method of using a low heat-generating cement as a material approach requires that a dedicated silo be installed in the raw concrete plant, which cannot be adopted in factories operating in ordinary facilities. Moreover, the expansion material leads to a cost increase of about 2,000 to 3,500 yen per 1 m ^{3, and} there is a situation that it is difficult to adopt in general construction. Therefore, recently, the number of cases using crack-inducing joints has been increasing, but joints must be inserted from the base to the top of the wall during construction, which is troublesome and costly for large structures. There is a problem of being big.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to be able to construct at a low cost while having a structure that hardly causes cracks in the wall body portion standing on the bottom plate portion. It is to provide a wall-like structure.

The wall-like structure according to the first aspect of the present invention is a concrete wall-like structure in which a wall body portion is erected on a bottom slab, and has a thickness equivalent to that of the wall body portion. The bottom plate part having the protruding ridge part is formed, and the upper wall part is formed by placing the concrete on the protruding part to form the wall part by the protruding part and the upper wall part. In the wall part, a plurality of vertical crack-inducing joints are formed at least on the ridge part, and when the crack-inducing joints are formed on both the ridge part and the upper wall part, the upper wall body the spacing of cracks induced joint which is formed in a portion size comb than the spacing of the cracks induced joint formed in the ridge portion, cracks induced joint formed in the ridge portion, cracks to reduce the degree of restraint of the top wall portion It is characterized by being a trigger joint .

  A wall-like structure according to a second aspect of the present invention is the wall-like structure according to the first aspect, wherein the bottom slab portion is made of concrete cast in the field, and the protruding portion is formed by concrete casting together with the bottom slab portion. It is characterized by being.

  A wall-like structure according to a third aspect of the present invention is the wall-like structure according to the first aspect, wherein the bottom slab portion is made of concrete cast in-situ, and the protruding portion is separately provided after the concrete of the bottom slab portion is hardened. It is characterized by being made from concrete.

  The wall-like structure according to claim 4 is the wall-like structure according to claim 1, wherein the bottom plate portion is composed of a plurality of continuous bottom plate panels made of precast concrete, and the protruding portion is the bottom plate portion. It is characterized in that it is integrally formed with the bottom plate panel body in a state of protruding from the bottom.

  The wall-like structure according to claim 5 is the wall-like structure according to claim 1, wherein the bottom plate portion is composed of a combination of a plurality of continuous block bodies made of precast concrete and a concrete portion that is cast in place. The ridge portion is characterized by being formed at the upper part of the block body.

  The wall-like structure of the present invention forms a bottom plate portion having a protruding portion protruding upward at a thickness corresponding to the wall portion, and concrete is cast on the protruding portion to form an upper wall portion. By doing so, the wall part is composed of the ridge part and the upper wall part, so that compared with standing the wall body directly on the bottom plate part, the restraint from the bottom plate part is reduced. Since it weakens and the generated temperature stress is reduced, cracking is suppressed. And since it only needs to form the bottom plate part which has a protrusion part, it can construct at low cost.

  FIG. 1 is a perspective view showing an example of a wall-like structure according to the present invention. This wall-shaped structure is a box culvert. That is, the bottom plate and the side wall of the box culvert constitute a wall-like structure. In addition, a in the figure schematically shows a reinforcing bar embedded in concrete, and the same applies to the following drawings.

  When the box culvert shown in FIG. 1 is formed, the bottom plate portion 1 is first formed by concrete on-site, and at that time, the protruding portion 2 is simultaneously formed on the bottom plate portion 1 with the thickness of the side wall. . The height of the protruding portion 2 is usually about 20 to 80 cm, but may be appropriately designed according to dimensions and materials. Next, the upper wall portion 3 and the top plate portion 4 are formed by pouring concrete on the ridge portion 2. Therefore, the side wall of the box culvert is a wall body portion in which the upper wall portion 3 overlaps the ridge portion 2. And since the upper wall part 3 is standingly arranged from the bottom plate part 1 via the protrusion part 2, the restraint from the bottom plate part 1 becomes weak, and the generated temperature stress becomes small.

  FIG. 2 is a perspective view showing another example of the wall-like structure according to the present invention. This wall-like structure is a box culvert similar to that shown in FIG. That is, the bottom plate and the side wall of the box culvert constitute a wall-like structure.

  When the box culvert shown in FIG. 2 is formed, the bottom plate portion 1 is first formed by concrete on site. Then, after the concrete of the bottom slab portion 1 is hardened, the ridge portion 2 is formed by separately casting concrete. This type of protruding portion 2 is preferably higher than that in the case of FIG. 1, but the height may be appropriately designed according to dimensions and materials as described above. Next, the upper wall portion 3 and the top plate portion 4 are formed by pouring concrete on the ridge portion 2. Also in the case of this box culvert, the side wall is a wall body portion in which the upper wall portion 3 is superimposed on the ridge portion 2. And since the upper wall part 3 is standingly arranged from the bottom plate part 1 via the protrusion part 2, the restraint from the bottom plate part 1 becomes weak, and the generated temperature stress becomes small.

  In such a wall-like structure composed of a bottom plate portion and a wall body portion, the boundary portion between the bottom plate portion and the wall body portion often receives a large cross-sectional force in design. Therefore, as shown in FIG. 1, it is desirable not to make this boundary portion a joint, but to separate the joint from the bottom plate portion. However, even in a wall-like structure having a seam at the boundary between the bottom plate portion 1 and the wall body portion as shown in FIG. 2, since the protrusion 2 is present, the restraint from the bottom plate portion 1 is weakened. This reduces the temperature stress that occurs and is effective in suppressing cracking.

  FIGS. 3 and 4 are perspective views showing modifications of the wall-like structure shown in FIGS. 1 and 2, respectively, and in each case, a plurality of vertical crack-inducing joints 5 are provided side by side on the side of the ridge portion 2. FIG. . Thus, if the crack induction joint 5 is provided in the protrusion part 2 and the performance can be exhibited reliably, the restraint with respect to the upper wall part 3 can be weakened significantly. As a result, temperature stress can be reduced and cracking can be suppressed.

  Induction of cracks in the ridge portion 2 occurs as follows. That is, in the case of the wall-like structure shown in FIG. 3 in which the ridge portion 2 is constructed simultaneously with the bottom slab portion 1, the upper wall portion 3 is driven at the initial age after the concrete is driven. Later, when the cement swells due to the heat of hydration of the cement, a tensile force acts on the ridge portion 2, thereby inducing a crack. Further, in the case of the wall-like structure shown in FIG. 4 in which the ridge portion 2 is constructed separately from the bottom plate portion 1, a tensile force acts when the temperature of the ridge portion 2 drops and after the upper wall body portion 3 is constructed. Therefore, cracks are induced at this time.

  FIGS. 5 and 6 are perspective views showing still other modifications of the wall-like structure shown in FIGS. 1 and 2, respectively, and in each case, a vertical crack-inducing joint 5 is provided in the ridge portion 2 side by side. The upper wall portion 3 is also provided with a crack-inducing joint 6.

  When the temperature stress is large, the crack of the upper wall portion 3 may not be suppressed only by the crack-inducing joint 5 of the ridge portion 2. In such a case, as shown in FIGS. 5 and 6, a crack-inducing joint 6 is also provided in the upper wall portion 3. However, if the crack-inducing joint 5 is provided in the ridge portion 2, the degree of restraint of the upper wall portion 3 is reduced, so that the interval between the crack-inducing joints 6 provided in the upper wall portion 3 may be increased. it can. Therefore, compared with the case where a crack-inducing joint is provided over the entire wall body, it is possible to rationalize the construction and reduce the cost.

  FIG. 7 is a perspective view showing another example of a wall-like structure according to the present invention. A box culvert is a target structure for this wall-like structure. That is, the bottom plate and the side wall of the box culvert constitute a wall-like structure. In the figure, “a” schematically shows a reinforcing bar embedded in concrete.

  When forming the box culvert shown in FIG. 7, first, a necessary number of precast concrete bottom plate panels 7 shown in FIG. 8 are prepared. The bottom slab panel body 7 used here has a ridge portion 7b protruding on both sides of the bottom slab portion 7a, and has a shape in which a reinforcing bar a protrudes above the ridge portion 7b. In this way, a plurality of bottom plate panels 7 are arranged side by side so that the ridge portions 7b are continuous, and then concreted on the ridge portions 7b to form the upper wall portion 3 and the top plate portion 4. .

  In the case of this box culvert, the side wall is a wall portion in which the upper wall portion 3 overlaps the ridge portion 7b. And since the upper wall part 3 will be in the state standing from the bottom plate part 7a via the protrusion part 7b, the restraint from the bottom plate part 7a will become weak, and the generated temperature stress will become small.

  The box culvert shown in FIG. 7 has precast concrete bottom slab panel bodies 7 arranged side by side. Therefore, there is a joint between adjacent bottom slab panel bodies 7, and the joint b of the ridge portion 7b is shown in FIG. Exhibits the same effect as the crack-induced joint shown in. However, if the temperature stress is so large that cracking of the upper wall portion 3 cannot be suppressed only by this joint b, cracking is induced in the upper wall portion 3 as shown in FIG. What is necessary is just to take the form which provided the joint.

  FIG. 9 is a perspective view showing a modification of the wall-like structure shown in FIG. This wall-shaped structure is composed of a combination of a plurality of continuous block bodies 8 whose bottom plate portions are made of precast concrete and a concrete portion 9 which is cast in place. The block body 8 used here has a rectangular parallelepiped shape, and an upper portion thereof forms a protruding portion 8a.

  The block body 8 is supplied to the construction site in any form shown in FIGS. In the case of Fig.10 (a), the block body 8 of the shape where the reinforcing bar a protruded in the downward side part and the upper part of the protrusion part 8a is used, respectively. FIG. 10B uses a structure in which two block bodies 8 are connected at a predetermined interval by reinforcing bars a protruding from the lower side.

  In forming the box culvert shown in FIG. 9, first, a necessary number of precast concrete block bodies 8 are prepared. Next, when the block body 8 of FIG. 10A is used, a plurality of block bodies 8 are arranged in two rows with the protruding portion 8a facing upward, and then the blocks installed in the two rows. Concrete is placed between the bodies 8. When the block body 8 shown in FIG. 10B is used, the block bodies 8 in pairs are arranged side by side with the ridges 8a facing upward, and then the installed block body 8 is placed. Make concrete in between. As a result, a bottom plate portion is formed by the plurality of continuous block bodies 8 and the concrete portion 9 which is cast on the spot, and the protruding portion 8a of the block body 8 protrudes from both sides of the bottom plate portion. After the bottom plate portion is formed in this way, the upper wall portion 3 and the top plate portion 4 are formed by concrete casting on the protruding portion 8a of the block body 8.

  In the case of this box culvert, the side wall is a wall body portion in which the upper wall portion 3 overlaps the protruding portion 8 a of the block body 8. And since the upper wall part 3 will be in the state standing from the bottom plate part via the protrusion part 8a, the restraint from a bottom plate part will become weak and the generated temperature stress will become small.

  FIG. 11 is a perspective view showing another modification of the wall-like structure shown in FIG. Similarly to the wall-shaped structure of FIG. 9, this wall-shaped structure is composed of a combination of a plurality of continuous blocks 10 made of precast concrete and a concrete portion 11 that has been cast in the field. The block body 10 used here has an L-shaped cross section in which the protruding portion 10b protrudes from the horizontal portion 10a.

  The block body 10 is supplied to the construction site in any form shown in FIGS. In the case of Fig.12 (a), the block body 10 of the shape where the reinforcing bar a protruded from the upper part of the protrusion part 10a and the side part of the horizontal part 10 is used, respectively. In the case of FIG. 12B, a structure in which two block bodies 10 are connected at a predetermined interval by a reinforcing bar a protruding from a side portion of the horizontal portion 10a is used.

  In forming the box culvert shown in FIG. 11, first, a necessary number of precast concrete block bodies 10 are prepared. Next, when the block bodies 10 in FIG. 12A are used, a plurality of block bodies 10 are arranged in two rows with the protruding portion 10b facing upward and placed outside, and then installed in the two rows. Concrete is placed between the block bodies 10 that have been made. When the block body 10 shown in FIG. 12B is used, the block bodies 10 in which two blocks are paired are arranged side by side with the protruding portion 10a facing upward, and then the installed block body 10 is placed. Make concrete in between. As a result, a bottom plate portion is formed by the plurality of continuous block bodies 10 and the concrete portion 11 cast in place, and the protruding portion 10b of the block body 10 projects from both sides of the bottom plate portion. After the bottom plate portion is formed in this way, the upper wall portion 3 and the top plate portion 4 are formed by placing concrete on the protruding portion 10b of the block body 10.

  In the case of this box culvert, the side wall is a wall body portion in which the upper wall portion 3 overlaps the protruding portion 10 b of the block body 10. And since the upper wall part 3 will be in the state standing from the bottom plate part via the protrusion part 10b, the restraint from a bottom plate part will become weak and the generated temperature stress will become small.

  Since these box culverts shown in FIGS. 9 and 11 are precast concrete blocks 8 and 10 arranged side by side, there is a joint b in the ridges 8a and 10b, and the joint b is a crack shown in FIG. Exhibits the same effect as the trigger joint. However, if the temperature stress is so large that cracking of the upper wall portion 3 cannot be suppressed only by this joint b, cracking is induced in the upper wall portion 3 as shown in FIG. What is necessary is just to take the form which provided the joint.

  In addition, when the precast concrete bottom slab panel body 7 and the block bodies 8 and 10 shown in FIGS. 7 to 12 are used, not only the prevention of cracking but also the labor saving and construction period in the construction of the box culvert and the wall structure are performed. Can be shortened, and rationalization of construction can be promoted.

  As described above, the embodiment of the present invention has been described in detail. However, the wall-shaped structure according to the present invention is not limited to the box culvert as described above. For example, a general wall-shaped structure as shown in FIG. And other various wall-like structures.

It is a perspective view which shows an example of the wall-shaped structure which concerns on this invention. It is a perspective view which shows the other example of the wall-shaped structure which concerns on this invention. It is a perspective view which shows the modification of the wall-shaped structure shown in FIG. It is a perspective view which shows the modification of the wall-shaped structure shown in FIG. It is a perspective view which shows another modification of the wall-shaped structure shown in FIG. It is a perspective view which shows another modification of the wall-shaped structure shown in FIG. It is a perspective view which shows the other example of the wall-shaped structure which concerns on this invention. It is a perspective view of the bottom plate panel body used for the wall-shaped structure shown in FIG. It is a perspective view which shows the modification of the wall-shaped structure shown in FIG. It is a perspective view of the block body used for the wall-shaped structure shown in FIG. It is a perspective view which shows another modification of the wall-shaped structure shown in FIG. It is a perspective view of the block body used for the wall-shaped structure shown in FIG. It is a perspective view which shows the example applied to the general wall-shaped structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bottom plate part 2 Projection part 3 Upper wall part 4 Top plate part 5,6 Crack induction joint 7 Bottom plate panel body 7a Bottom plate part 7b Projection part 8 Block body 8a Projection part 9 Concrete part 10 Block body 10a Horizontal part 10b Ridge part 11 concrete part

Claims (5)

A concrete wall-like structure in which a wall body portion is erected on the bottom plate portion, forming a bottom plate portion having a protruding portion protruding upward at a thickness corresponding to the wall body portion, By forming concrete on the ridge part to form the upper wall part, the ridge part and the upper wall part constitute the wall part,
In the wall portion, a plurality of vertical crack-inducing joints are formed at least on the ridge portion, and when the crack-inducing joint is formed on both the ridge portion and the upper wall portion, the spacing of cracks induced joint formed in the upper wall portion size comb than the spacing of the cracks induced joint formed in the ridge portion,
The wall-like structure characterized in that the crack-inducing joint formed in the protruding portion is a crack-inducing joint for reducing the degree of restraint of the upper wall portion .   2. The wall-like structure according to claim 1, wherein the bottom plate portion is made of concrete cast on the spot, and the protruding portion is formed by concrete casting together with the bottom plate portion.   2. The wall-like structure according to claim 1, wherein the bottom plate portion is made of concrete cast on the spot, and the protruding portion is formed by separately casting concrete after the concrete of the bottom plate portion is hardened.   2. The wall-like shape according to claim 1, wherein the bottom plate portion is composed of a plurality of continuous bottom plate panels made of precast concrete, and the ridge portion is integrally formed with the bottom plate panel body so as to protrude from the bottom plate portion. Structure.   2. The wall-like shape according to claim 1, wherein the bottom plate portion is formed of a combination of a plurality of continuous block bodies made of precast concrete and a concrete portion that is cast on the spot, and the ridge portion is formed at an upper portion of the block body. Artifacts.

Images