Concrete Wall Construction Method

Abstract

To provide a concrete wall construction method for constructing a concrete wall on a vertical construction surface at a wall construction floor without any wall on the lower floor side, which technique can rationalize and simplify timbering for the concrete wall constructed on the vertical construction surface.SOLUTION: A concrete wall construction method for constructing a concrete wall 3 on a vertical construction surface 2 at a wall construction floor F3 without any wall on the lower floor side comprises: a lower side wall construction step for constructing a concrete wall 16 of a lower side part 6 of the vertical construction surface by separating a concrete wall construction part of the vertical construction surface 2 to an upper side part 5 and the lower side part 6 of the vertical construction surface in a vertical direction; and an upper side wall construction step for constructing a concrete wall 15 of the upper side part 5 of the vertical construction surface after jointing the concrete wall 16 of the lower side part 6 of the vertical construction surface, constructed by the lower side wall construction step, to columns 1 on edge sides of both sides of the vertical construction surface 2.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a concrete wall construction method for constructing a concrete wall on the vertical structural plane of a wall construction floor where no wall exists on the lower floor side. [Background technology]

[0002] On a wall construction floor above a floor where no wall exists, a concrete wall such as a load-bearing wall may be constructed on a vertical structural plane where no wall exists below (see, for example, Patent Document 1). In such a concrete wall construction method, shoring for supporting the concrete wall constructed over the entire vertical structural surface of the wall construction floor must be installed on the floor below the wall construction floor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 09-264049 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional concrete wall construction methods, when a concrete wall is constructed in one go across the entire vertical structural surface of the wall construction floor, the support work installed on the lower floor must be large enough to support the weight of the concrete wall across the entire vertical structural surface. For example, when installing vertical shoring on the floor below the wall construction floor and using that shoring to support a concrete wall constructed across the entire vertical structural surface of the wall construction floor, in order to keep the deflection of the floor on which the shoring is installed within an acceptable range, it may be necessary to install shoring on each of the multiple floors below the wall construction floor and distribute the weight of the concrete wall constructed across the entire vertical structural surface to the floors of each of the multiple floors, which requires very large-scale and complicated work. In view of this situation, the main objective of the present invention is to provide a technology that can rationally and simply support a concrete wall constructed on a vertical structural surface of a wall construction floor where there is no wall on the lower floor, in a concrete wall construction method in which a concrete wall is constructed on the vertical structural surface of the wall construction floor. [Means for solving the problem]

[0009] The present invention 1 The characteristic configuration is: A concrete wall construction method for constructing a concrete wall on a vertical structural plane of a wall construction floor where no wall exists on the lower floor side, comprising: The concrete wall construction portion of the vertical structural plane is divided into an upper portion of the vertical structural plane and a lower portion of the vertical structural plane, A lower wall construction step is carried out to construct a concrete wall of the lower part of the vertical structural face, After the concrete wall of the lower part of the vertical structural face constructed by executing the lower wall construction step is joined to the columns on both sides of the vertical structural face, An upper wall construction step is carried out to construct a concrete wall of the upper part of the vertical structural plane; In the upper wall construction process, wall reinforcing bars to be placed in the upper part of the vertical structural surface are unitized into wall reinforcing bar units, which are pre-assembled on the ground, and the pre-assembled wall reinforcing bar units are then lifted and installed on the upper part of the vertical structural surface.

[0010] According to this configuration, when a concrete wall is constructed on a vertical structural surface on a floor where no wall exists below, the lower wall construction step is carried out to construct the concrete wall on the lower part of the vertical structural surface. At this time, the concrete wall constructed on the vertical structural surface does not correspond to the entire vertical structural surface, but corresponds to the lower part of the vertical structural surface, which is a part of it. Therefore, when the lower wall construction step is carried out, the support work for the concrete wall in the lower part of the vertical structural plane to be constructed can be relatively simplified. Next, the lower wall construction process is carried out, and the constructed concrete wall of the lower part of the vertical structural plane is joined to the columns on both sides of the vertical structural plane. Then, the weight of the concrete wall of the lower part of the vertical structural plane is transferred to and supported by the columns on both sides, so that some or all of the shoring used in the lower wall construction process can be removed. Next, the upper wall construction process is carried out to construct the concrete wall of the upper part of the vertical structural face. In this case, the weight of the concrete wall of the upper part of the vertical structural plane constructed on the vertical structural plane is transmitted to and supported by the columns on both sides to which the concrete wall is joined via the concrete wall of the lower part of the vertical structural plane located below. Therefore, during the upper wall construction process, it is possible to omit or greatly simplify the support work for the concrete wall of the upper part of the vertical structural plane to be constructed. Therefore, the present invention provides a technology that can rationally and simply support the concrete wall constructed on the vertical structural surface of a wall construction floor where there is no wall on the lower floor side in a concrete wall construction method in which a concrete wall is constructed on the vertical structural surface. Furthermore, According to this configuration, in the upper wall construction process, there is no need to perform the complicated task of directly placing wall reinforcement bars on the upper part of the vertical structural face, which is surrounded by the beams on the upper edge of the vertical structural face, the concrete walls on the lower part of the vertical structural face, and the columns on both sides, and pre-assembled wall reinforcement units can be installed with relatively simple work.

[0011] The present invention 2 The characteristic configuration is: A concrete wall construction method for constructing a concrete wall on a vertical structural plane of a wall construction floor where no wall exists on the lower floor side, comprising: The concrete wall construction portion of the vertical structural plane is divided into an upper portion of the vertical structural plane and a lower portion of the vertical structural plane, A lower wall construction step is carried out to construct a concrete wall of the lower part of the vertical structural face, After the concrete wall of the lower part of the vertical structural face constructed by executing the lower wall construction step is joined to the columns on both sides of the vertical structural face, An upper wall construction step is carried out to construct a concrete wall of the upper part of the vertical structural plane; In the lower wall construction process, a first shoring that supports the concrete wall constructed on the lower portion of the vertical structural face is installed in a vertical position on the floor of the first shoring installation floor, which is the floor below the wall construction floor, and a second shoring that supports the floor of the first shoring installation floor is installed on the floor of the second shoring installation floor, which is the floor below the first shoring installation floor, in an inclined position with its lower end side closer to the column, After the concrete wall constructed on the lower part of the vertical structural face is joined to the columns on both sides of the vertical structural face, the first support and the second support are removed and the upper wall construction process is carried out.

[0012] According to this configuration, when a concrete wall is constructed on a vertical structural surface on a floor where no wall exists below, the lower wall construction step is carried out to construct the concrete wall on the lower part of the vertical structural surface. At this time, the concrete wall constructed on the vertical structural surface does not correspond to the entire vertical structural surface, but corresponds to the lower part of the vertical structural surface, which is a part of it. Therefore, when the lower wall construction step is carried out, the support work for the concrete wall in the lower part of the vertical structural plane to be constructed can be relatively simplified. Next, the lower wall construction process is carried out, and the constructed concrete wall of the lower part of the vertical structural plane is joined to the columns on both sides of the vertical structural plane. Then, the weight of the concrete wall of the lower part of the vertical structural plane is transferred to and supported by the columns on both sides, so that some or all of the shoring used in the lower wall construction process can be removed. Next, the upper wall construction process is carried out to construct the concrete wall of the upper part of the vertical structural face. In this case, the weight of the concrete wall of the upper part of the vertical structural plane constructed on the vertical structural plane is transmitted to and supported by the columns on both sides to which the concrete wall is joined via the concrete wall of the lower part of the vertical structural plane located below. Therefore, during the upper wall construction process, it is possible to omit or greatly simplify the support work for the concrete wall of the upper part of the vertical structural plane to be constructed. Therefore, the present invention provides a technology that can rationally and simply support the concrete wall constructed on the vertical structural surface of a wall construction floor where there is no wall on the lower floor side in a concrete wall construction method in which a concrete wall is constructed on the vertical structural surface. Furthermore, According to this configuration, when the lower wall construction step is performed, the first shoring is installed in a vertical position on the floor of the first shoring installation floor, which is the floor below the wall construction floor, and the second shoring is installed in an inclined position on the floor of the second shoring installation floor, which is the floor below the first shoring installation floor, The weight of the concrete wall on the lower part of the vertical structural plane to be constructed can be rationally supported by the floors of the first and second support floors and the columns on both sides of the vertical structural plane. In addition, the first and second supports can be removed when the concrete walls constructed on the lower part of the vertical structural face are joined to the columns on both sides of the vertical structural face, and the upper wall construction process can be carried out. A third characteristic configuration of the present invention is that in the lower wall construction step, a precast concrete wall member is erected at the center of the lower portion of the vertical structural face, and then concrete is poured into the joints on both sides of the wall member to construct a concrete wall of the lower portion of the vertical structural face; The upper wall construction step is carried out after the concrete poured into the joint in the lower wall construction step has developed strength. According to this configuration, in the lower wall construction process, the central concrete wall, which is part of the lower part of the vertical structural face, is constructed with pre-fabricated precast concrete wall members, rather than with cast-in-place concrete, which requires the installation of large-scale formwork and shoring at short intervals, thereby improving work efficiency by omitting the installation of formwork and shoring at short intervals. The joints on both sides of the wall members are constructed with cast-in-place concrete, and as the concrete develops its strength, it is determined that the concrete wall on the lower part of the vertical structural plane, consisting of the two joints and the wall members erected between them, has been joined to the columns on both sides of the vertical structural plane, and the next upper wall construction process can then be carried out. [Brief explanation of the drawings]

[0013] [Figure 1]FIG. 1 is an elevation view showing a state of a first step of a lower wall construction process in a concrete wall construction method according to an embodiment of the present invention. [Figure 2] 1 is a side view showing a state of a first step of a lower wall construction process in a concrete wall construction method according to an embodiment of the present invention; [Figure 3] FIG. 1 is an elevation view showing a second step of the lower wall construction process in the concrete wall construction method of the present embodiment. [Figure 4] 1 is a side view showing a state of a second step of the lower wall construction process in the concrete wall construction method of the present embodiment. [Figure 5] FIG. 1 is an elevation view showing a state of a third step of the lower wall construction process in the concrete wall construction method of the present embodiment. [Figure 6] 1 is a side view showing a state of a third step of the lower wall construction process in the concrete wall construction method of the present embodiment. [Figure 7] FIG. 1 is an elevation view showing a state of a first step of the upper wall construction process in the concrete wall construction method of the present embodiment. [Figure 8] 1 is a side view showing a state of a first step of the upper wall construction process in the concrete wall construction method of the present embodiment. [Figure 9] FIG. 1 is an elevation view showing a second step of the upper wall construction process in the concrete wall construction method of the present embodiment. [Figure 10] 1 is a side view showing a state of a second step of the upper wall construction process in the concrete wall construction method of the present embodiment. [Figure 11] FIG. 1 is an elevation view showing a state of a third step of the upper wall construction process in the concrete wall construction method of the present embodiment. [Figure 12] 1 is a side view showing a state of a third step of the upper wall construction process in the concrete wall construction method of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of a concrete wall construction method according to the present invention will be described with reference to the drawings. The concrete wall construction method of this embodiment (hereinafter sometimes referred to as "this wall construction method") is configured as a method for constructing a concrete wall 3 such as a load-bearing wall on a vertical structural face 2 of a wall construction floor where there is no wall on the floor below, as shown in Figures 11 and 12. Note that in this embodiment, for ease of explanation, the wall construction floor is assumed to be the third floor F3, but this wall construction floor may be any floor where there is no wall on the floor below.

[0015] In this wall construction method, the concrete wall construction portion of the vertical structural plane 2 is divided into an upper part 5 of the vertical structural plane and an upper part 6 of the vertical structural plane, and then a lower wall construction process for constructing a concrete wall 16 of the lower part 6 of the vertical structural plane and an upper wall construction process for constructing a concrete wall 15 of the upper part 5 of the vertical structural plane are carried out in sequence. Then, as will be described in detail later, after the concrete wall 16 of the lower part 6 of the vertical structural face constructed by carrying out the lower wall construction process is joined to the columns 1 on both sides of the vertical structural face 2, the concrete wall 15 of the upper part 5 of the vertical structural face is constructed by carrying out the upper wall construction process. In this way, this wall construction method is capable of rationally and simply supporting the concrete wall 3 constructed on the vertical structural face 2. The above-mentioned lower wall construction process is configured to sequentially carry out the first step of the lower wall construction process (Figures 1 and 2), the second step of the lower wall construction process (Figures 3 and 4), and the third step of the lower wall construction process (Figures 5 and 6), which will be described in detail later. On the other hand, the upper wall construction process is configured to sequentially execute the first step of the upper wall construction process (Figures 7 and 8), the second step of the upper wall construction process (Figures 9 and 10), and the third step of the upper wall construction process (Figures 11 and 12), which will be described in detail later. Each of these steps will be described in detail below.

[0016] (First step in the lower wall construction process) In the first step of the lower wall construction process shown in Figures 1 and 2, a precast concrete wall member 20 is erected at the center of the lower portion 6 of the vertical structural face 2 of the third floor F3 before the slab S3 of the third floor F3 is constructed. At this time, a first shoring 51 is installed at the center of the slab S2 of the second floor F2, which serves as the first shoring installation floor below the third floor F3, and a second shoring 55 is installed on the slab S1 of the first floor F1, which serves as the second shoring installation floor below the second floor F2. Furthermore, the first shoring 51 is installed in a vertical position, while the second shoring 55 is installed in an inclined position with its upper end located in the same center as the first shoring 51 and its lower end located in a corner near the column 1. With this configuration, the weight of the precast concrete wall member 20 is rationally supported by the first support structure 51 and the second support structure 55, and by the slabs S1, S2 on the first floor F1 and the second floor F2, and the columns 1 on both sides of the vertical structural face 2.

[0017] The precast concrete wall member 20 has a wall portion 21 that forms the central wall of the lower portion 6 of the vertical structural face, and a flat beam portion 25 at its lower end that is installed within the slab S3 of the third floor F3 and has the same height as the slab S3. A plurality of wall main reinforcements 23 that are connected to each of the wall main reinforcements provided in the upper portion 5 of the vertical structural face protrude vertically from the upper end surface of the wall portion 21 of the wall member 20 toward the upper portion 5 of the vertical structural face. A plurality of horizontal connecting bars 22 that are connected to each of the horizontal connecting bars protruding from the column 1 protrude horizontally from both side surfaces of the wall portion 21 of the wall member 20 toward the joints 30 on both sides. A plurality of beam main reinforcements 26 that are connected to each of the beam main reinforcements protruding from the column 1 protrude horizontally from both side surfaces of the beam portion 25 of the wall member 20 toward the joints 30 on both sides. Furthermore, a plurality of horizontal connecting bars 27, which are connected to a plurality of slab bars provided in the front and rear slabs S3, protrude from the front and rear surfaces of the beam portion 25 of the wall member 20 toward the area where the slab S3 is to be formed. In this embodiment, the beam portion 25 is configured as a flat beam installed inside the slab S3, but it may also be a normal beam.

[0018] (Second step of the lower wall construction process) Following the first step of the lower wall construction process, the second step of the lower wall construction process shown in Figures 3 and 4 is carried out. In this second step of the lower wall construction process, reinforcement work and formwork installation work are carried out for joints 30 on both sides of the wall member 20. A plurality of wall main reinforcements 31 are arranged in these joints 30, extending to the upper part 5 of the vertical structural face. Furthermore, a plurality of beam stirrups 32 are attached to a plurality of beam main reinforcements 26 protruding from the beam part 25 of the wall member 20. Additionally, formwork 53 for pouring concrete into the joints 30 is installed below and around the front and back (not shown) of the joints 30 on both sides. The formwork 53 is supported by first supports 52 in a vertical position installed on both sides on the slab S2 of the second floor F2. Furthermore, the supports 51, 52, 55 installed in this state only need to be capable of supporting the relatively lightweight concrete wall 16 (Figure 5) of the lower part 6 of the vertical structural face, which is constructed from concrete poured into the above-mentioned wall member 20 and the joints 30 on both sides of it, and are therefore simpler than those required to support the extremely heavy concrete wall 3 (Figure 11) constructed over the entire vertical structural face 2.

[0019] (Third step of the lower wall construction process) Following the second step of the lower wall construction process, the third step of the lower wall construction process shown in Figures 5 and 6 is carried out. In this third step of the lower wall construction process, concrete is poured into the slab S3 of the third floor F3, and concrete is poured into the joints 30 on both sides of the wall members 20. The concrete poured into the joints 30 on both sides and the wall portion 21 of the wall member 20 arranged in the center form the concrete wall 16 of the lower portion 6 of the vertical structural face, which is the lower portion of the vertical structural face 2. Furthermore, when the concrete poured into the joints 30 on both sides hardens and develops its strength, the concrete wall 16 of the lower part 6 of the vertical structural face is joined to the columns 1 on both sides of the vertical structural face 2, and its weight is transferred to and supported by the columns 1 on both sides. Therefore, the shoring 51, 52, 55 and formwork 53 are removed when the concrete poured into the joints 30 on both sides has developed an appropriate strength. Note that this removal does not have to be done when the concrete poured into the joints 30 has fully developed its strength. Furthermore, the shoring 51, 52, 55 may be left in place as appropriate even after the concrete poured into the joints 30 has developed its strength.

[0020] (First step in the upper wall construction process) After the first to third steps of the lower wall construction process are performed and the concrete wall 16 of the lower portion 6 of the vertical structural face is joined to the columns 1 on both sides of the vertical structural face 2, the first step of the upper wall construction process shown in FIGS. 7 and 8 is performed. In this first step of the upper wall construction process, wall reinforcing bar units 40, each unitized from the wall reinforcing bars to be placed in the upper portion 5 of the vertical structural face, are pre-assembled on the ground, and the pre-assembled wall reinforcing bar units 40 are then lifted and installed on the upper portion 5 of the vertical structural face. In this wall reinforcing bar unit 40, multiple wall main reinforcements 41 serving as the wall reinforcing bars to be placed in the upper portion 5 of the vertical structural face hang down from the beam main reinforcements 42 and stirrups 43 of the beams installed in the slab S4 on the upper floor. The upper ends of the wall main reinforcements 41 are bent horizontally and extend as main reinforcements 44 of the slab S4 on the upper floor. The wall reinforcing bar unit 40 configured in this way is lowered from the upper floor side and installed on the upper part 5 of the vertical structural face in a form in which the wall main bars 41 are inserted from above into the upper part 5 of the vertical structural face. These wall main bars 41 are then joined to the wall main bars 23, 31 protruding from the upper end surface of the wall member 20. In this step, there is no need to perform the complicated task of directly placing wall main reinforcement bars 41, etc., on the upper part 5 of the vertical structural face surrounded by the concrete wall 16 of the lower part 6 of the vertical structural face and the columns 1 on both sides, and the wall reinforcing bar units 40 that have been pre-assembled on the ground can be installed with relatively simple work.

[0021] (Second step of the upper wall construction process) Following the first step of the upper wall construction process, the second step of the upper wall construction process is carried out as shown in Figures 9 and 10. In this second step of the upper wall construction process, the reinforcing bars 46 are arranged and the reinforcing bars are joined in the upper part 5 of the vertical structural surface on which the wall reinforcing bar units 40 are installed.

[0022] (Third step of the upper wall construction process) Following the second step of the upper wall construction process, the third step of the upper wall construction process shown in Figures 11 and 12 is carried out. In this third step of the upper wall construction process, appropriate formwork (not shown) is installed for the upper part 5 of the vertical structural face, and concrete is then poured. The poured concrete then constructs the concrete wall 15 of the upper part 5 of the vertical structural face, which is the upper part of the vertical structural face 2. At this time, the weight of the concrete poured into the upper part 5 of the vertical structural face constructed on the vertical structural face 2 is effectively transmitted and supported by the columns 1 on both sides to which the concrete walls 16 are joined via the concrete walls 16 of the lower part 6 of the vertical structural face located below. Therefore, support for the concrete poured into the upper part 5 of the vertical structural face can be omitted or extremely simplified.

[0023] [Another embodiment] Other embodiments of the present invention will be described below. Note that the configurations of the embodiments described below are not limited to being applied independently, but can also be applied in combination with the configurations of other embodiments.

[0024] (1) In the above embodiment, the precast concrete wall member 20 erected at the center of the lower portion 6 of the vertical structural plane has a beam portion 25 that is installed inside the slab S3 at the lower end of the wall portion 21 that constitutes the wall at the center of the lower portion 6 of the vertical structural plane. However, it is also possible to erect only the wall portion 21, excluding the beam portion 25, as a precast concrete wall member at the center of the lower portion 6 of the vertical structural plane.

[0025] (2) In the above embodiment, in the lower wall construction process, the concrete wall 16 of the lower part 6 of the vertical structural face is constructed in the center using precast concrete wall members 20, and only the joints 30 on both sides are constructed using cast-in-place concrete. However, the entire concrete wall 16 of the lower part 6 of the vertical structural face may be constructed using cast-in-place concrete.

[0026] (3) In the above embodiment, in the upper wall construction process, wall reinforcement units 40, which are units made from wall main reinforcements 41 and the like to be placed in the upper part 5 of the vertical structural surface, are pre-assembled on the ground, and the wall reinforcement units 40 are then lifted and installed on the upper part 5 of the vertical structural surface. However, the configuration of the wall reinforcement units 40 can be changed as appropriate, and reinforcement work for the upper part 5 of the vertical structural surface may be carried out on site without using the wall reinforcement units 40.

[0027] (4) In the above embodiment, in the lower wall construction process, the first supports 51, 52 that support the concrete wall 16 constructed on the lower part 6 of the vertical structural face are installed in a vertical position on the slab S2 of the second floor F2, and the second support 55 that supports the slab S2 of the second floor F2 is installed on the slab S1 of the first floor F1 in an inclined position with its lower end closer to the column 1, but the installation state of these supports may be changed as appropriate. [Explanation of symbols]

[0028] 1 pillar 2 Vertical plane 3. Concrete wall 5 Upper part of vertical structural plane 6 Lower part of vertical structure 15 Concrete wall of the upper part of the vertical structural plane 16 Concrete wall of lower part of vertical structure 20 Wall components 30 Joint 40 Wall reinforcement units 41 Wall reinforcement (wall rebar) 51 1st shoring 52 1st shoring 55 2nd shoring F1 1st floor (2nd support installation floor) F2 2nd floor (first support installation floor) F3 3rd floor (wall construction floor)

Claims

1. A concrete wall construction method for constructing a concrete wall on a vertical structural plane of a wall construction floor where there is no wall on the lower floor side, comprising: The concrete wall construction portion of the vertical structural plane is divided into an upper portion of the vertical structural plane and a lower portion of the vertical structural plane, A lower wall construction step is carried out to construct a concrete wall of the lower part of the vertical structural face, After the concrete wall of the lower part of the vertical structural face constructed by executing the lower wall construction step is joined to the columns on both sides of the vertical structural face, An upper wall construction step is carried out to construct a concrete wall of the upper part of the vertical structural plane; In the upper wall construction process, a wall reinforcing bar unit formed by unitizing the wall reinforcing bars to be placed in the upper part of the vertical structural surface is pre-assembled on the ground, and the pre-assembled wall reinforcing bar unit is then lifted and installed on the upper part of the vertical structural surface.

2. A concrete wall construction method for constructing a concrete wall on a vertical structural plane of a wall construction floor where no wall exists on the lower floor side, comprising: The concrete wall construction portion of the vertical structural plane is divided into an upper portion of the vertical structural plane and a lower portion of the vertical structural plane, A lower wall construction step is carried out to construct a concrete wall of the lower part of the vertical structural face, After the concrete wall of the lower part of the vertical structural face constructed by executing the lower wall construction step is joined to the columns on both sides of the vertical structural face, An upper wall construction step is carried out to construct a concrete wall of the upper part of the vertical structural plane; In the lower wall construction process, a first shoring that supports the concrete wall constructed on the lower portion of the vertical structural face is installed in a vertical position on the floor of a first shoring installation floor that is the floor below the wall construction floor, and a second shoring that supports the floor of the first shoring installation floor is installed on the floor of a second shoring installation floor that is the floor below the first shoring installation floor in an inclined position with its lower end side closer to the column, A concrete wall construction method in which, after the concrete wall constructed on the lower part of the vertical structural face is joined to the columns on both sides of the vertical structural face, the first support and the second support are removed and the upper wall construction process is carried out.

3. In the lower wall construction step, a precast concrete wall member is erected at the center of the lower portion of the vertical structural face, and then concrete is poured into the joints on both sides to construct the concrete wall of the lower portion of the vertical structural face.

3. The concrete wall construction method according to claim 1, wherein the upper wall construction step is carried out after the concrete poured into the joint in the lower wall construction step has developed strength.

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