Method for constructing a structure using precast components

Abstract

To facilitate the application of PPRC structures to long structures.SOLUTION: A PC member 11A, which is the lowest layer, is a block with a steel cutting edge on the lower side, and PC members 11B to 11F are sequentially laminated thereon. A PC member 12 is laminated on the PC member 11F, and PC members 13A to 13I are further laminated thereon in order. The lower PC members 11A-11F are first PC members having a common structure corresponding to the PC structure, and the upper PC members 13A-13I are second PC members having a common structure corresponding to the PPRC structure. In FIG. 1, a first laminate 110 is formed by laminating the first PC members on the lower side, and a second laminate 130 is formed by laminating the second PC members on the upper side. The PC member (intermediate PC member) 12 that is intermediate between the first laminate 110 and the second laminate 130 has the characteristics of both the first PC member and the second PC member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a construction method for constructing a structure using precast members (precast concrete members: PC members). [Background technology]

[0002] The PC well method is known as a construction method for constructing structures such as bridge pier foundations and shafts. In the PC well method, for example, short cylindrical concrete PC members (precast concrete members or precast members) are successively sunk into the ground, pressed in, and stacked to construct a long cylindrical PC well structure. At this time, tensioning work is performed using tendons for each PC member, allowing prestress to be applied. The PC members used in the PC well method can be manufactured in an appropriate environment at a location different from the construction site, making it easy to ensure their quality, facilitating construction and shortening the construction period.

[0003] As shown in Non-Patent Document 1, PC well structures constructed by stacking PC members in the PC well construction method are classified into two types according to their structure: a PC (Prestressed Concrete) structure and a PPRC (Precast Prestressed Reinforced Concrete) structure.

[0004] In a PC structure, PC steel bars (tension members) are provided in the vertical direction (stacking direction) for each PC member, and tension (prestress) is applied to each PC member by tightening nuts on these PC steel bars. At this time, tensioning can be applied to the upper PC member while the PC steel bars of the lower PC member and the PC steel bars of the PC member stacked above are connected with couplers and stacked. The positions of the PC steel bars in each PC member are set so that they overlap so that they can be connected with couplers when stacked.

[0005] When the structure or PC member is cylindrical, a large number of PC steel rods can be arranged along the circumferential direction, allowing a large prestress to be applied uniformly to each PC member, thereby suppressing the occurrence of cracks in the PC well structure and achieving high durability.

[0006] On the other hand, PPRC structures are similar to PC structures in that PC steel bars are used and stacked in each PC member. However, in PPRC structures, multiple reinforcing bars are also installed that penetrate the PC well structure vertically after stacking. In this case, the entire PC well structure is reinforced with reinforcing bars, so this structure has high strength against horizontal stress and is particularly suitable for structures that require earthquake resistance. The prestress applied to each PC member in PPRC structures is sufficient to be the minimum value required for construction.

[0007] PC structures and PPRC structures use PC members with structures that correspond to each structure. Specifically, PC members for PC structures are formed with many tendon through-holes through which PC steel bars (tension bars) pass so that the PC steel bars and nuts and anchor plates used during tensioning can be attached. PC members for PPRC structures also have similar tendon through-holes, but there are fewer of them than in PC structures, and instead there are many rebar through-holes through which rebar passes. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] PC Well Construction Method Research Group HP, https: / / www.pc-well.gr.jp / pcwell.php Summary of the Invention [Problem to be solved by the invention]

[0009] PPRC structures are particularly favorable for structures that require earthquake resistance, but when structures are long, they require correspondingly long rebars. In this case, it was not easy to insert the long rebars into the rebar through holes after all the PC components had been stacked. Also, in order to fix the rebars in place within the PPRC structure, the rebar insertion holes must be filled with filler (mortar before hardening) after all the PC components have been stacked, before the rebars are inserted and the filler is allowed to harden. In this case, if the rebars are long, the filler may harden before the rebars have been inserted, making this task difficult.

[0010] For this reason, a construction method was required that would allow the PPRC structure to be easily applied to long structures.

[0011] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide an invention that solves the above problems. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention has the following configuration. The method of constructing a structure using precast members of the present invention is a method of constructing a structure using precast members, comprising the steps of: constructing a structure by submerging a structure in which a plurality of precast members are stacked after tendons have been installed and tensioned; and providing a plurality of first precast members as the precast members, each of which has a plurality of tendon through holes through which the tendons pass in the stacking direction; and a plurality of second precast members, each of which has a smaller number of tendon through holes than in the first precast members, and a plurality of reinforcing bar through holes through which reinforcing bars pass in the stacking direction. The method includes a first stacking step of obtaining a first stack in which a plurality of first precast members are stacked in a state in which the tendons have been installed in each of the tendon through holes and tensioned, and submerging the first stack; and a second stacking step of obtaining a second stack in which a plurality of second precast members are stacked in a state in which the tendons have been installed in each of the tendon through holes and tensioned, the reinforcing bar through holes of the plurality of second precast members are communicated in the stacking direction, the second stack being further stacked on the first stack, and 2 The method comprises a second stacking process for sinking the stack, and a reinforcing bar installation process for inserting and fixing the reinforcing bars into each of the reinforcing bar through holes that are connected in the stacking direction in the second stack, so that the reinforcing bars overlap with all of the second precast members in the stacking direction but do not overlap with the first stack. The method of constructing a structure using precast members of the present invention is characterized in that an intermediate precast member is provided between the first stack and the second stack, the intermediate precast member having a plurality of tendon through holes corresponding to each of the tendon through holes in the first precast member and a plurality of reinforcing bar through holes corresponding to each of the reinforcing bar through holes in the second precast member, in the second stacking process, the second precast members are stacked so that the reinforcing bar through holes in the intermediate precast member and all of the second precast members are connected in the stacking direction, and in the reinforcing bar installation process, the reinforcing bars are inserted and fixed into each of the reinforcing bar through holes so that they overlap all of the second stack and the intermediate precast members in the stacking direction. The method of constructing a structure using precast members of the present invention is characterized in that the value of prestress applied to the second precast member by the tensioning operation in the second stacking process is set to be smaller than the value of prestress applied to the first precast member by the tensioning operation in the first stacking process. The present invention is characterized in that the first precast member and the second precast member both have a cylindrical shape with a central axis parallel to the stacking direction, and the multiple tendon through holes and the multiple reinforcing bar through holes are formed in a circumferential direction around the central axis in the cylindrical shape and distributed therearound. Effect of the Invention

[0013] Since the present invention is configured as described above, it is possible to easily apply the PPRC structure to long structures. [Brief description of the drawings]

[0014] [Figure 1] 1 is a vertical cross-sectional view showing the configuration of a structure constructed by a construction method according to an embodiment of the present invention. [Diagram 2] 3 is a cross-sectional view perpendicular to the vertical direction of a first precast member used in a construction method according to an embodiment of the present invention. FIG. [Diagram 3] 4 is a cross-sectional view perpendicular to the vertical direction of a second precast member used in a construction method according to an embodiment of the present invention. FIG. [Figure 4] FIG. 2 is a vertical cross-sectional view of an intermediate precast member used in a construction method according to an embodiment of the present invention. [Diagram 5] 1 is an example of a flowchart of a construction method according to an embodiment of the present invention. [Figure 6] 1A to 1C are cross-sectional views (part 1) illustrating steps of a construction method according to an embodiment of the present invention. [Figure 7] 5A to 5C are cross-sectional views (part 2) of the process of the construction method according to the embodiment of the present invention. [Figure 8] 5A to 5C are cross-sectional views (part 3) of the process of the construction method according to the embodiment of the present invention. [Figure 9] 4 is a cross-sectional view showing a structure around a tendon in a construction method according to an embodiment of the present invention. FIG. [Figure 10] 4 is a cross-sectional view showing the structure around the reinforcing bar in a construction method according to an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A method for constructing a structure according to an embodiment of the present invention will be described. This construction method is a type of PC well construction method, in which multiple PC members (precast concrete members or precast members) are stacked vertically, and prestress is applied to each PC member using PC steel bars (tension members). In addition, vertical rebars are also used, providing high strength against horizontal stress.

[0016] FIG. 1 is a cross-sectional view perpendicular to the vertical direction showing the structure of a structure 1 constructed by this construction method. Here, this structure 1 is used, for example, as the foundation of a bridge pier, and has a long, approximately cylindrical shape with a central axis along the vertical direction, and a laminated structure in which 16 short PC members are stacked vertically is pressed into the ground G. This construction method is characterized by the configuration of the PC members used here and the construction method associated therewith. As in the case of the well-known PC well construction method, each PC member is individually composed mainly of concrete. As will be described later, in reality, inside this structure 1, a concrete layer (base slab concrete layer) is provided at the bottom, and a soil layer (filled soil layer) is provided at the top, but these are omitted in FIG. 1, and only the PC members are shown in FIG. 1.

[0017] PC member 11A, which is the bottom layer in Fig. 1, is a block with a steel cutting edge on the underside, and PC members 11B to 11F are layered in sequence on top of this. PC member 12 is layered on top of PC member 11F, and PC members 13A to 13I are layered in sequence on top of that. PC member 13I, which is the top layer, is exposed from the ground G. Note that in reality, a thin bonding layer made of an epoxy adhesive is formed between adjacent PC members in the layering direction (vertical direction) in Fig. 1, but this is omitted in Fig. 1.

[0018] Here, the lower PC members 11A-11F are first PC members (first precast members) having a common structure corresponding to the PC structure, and the upper PC members 13A-13I are second PC members (second precast members) having a common structure corresponding to the PPRC structure. Therefore, in Fig. 1, a first stacked body 110 is formed by stacking the first PC members on the lower side, and a second stacked body 130 is formed by stacking the second PC members on the upper side.

[0019] The PC member (intermediate PC member) 12 between the first laminate 110 and the second laminate 130 has the characteristics of both the first PC member and the second PC member. Fig. 2 shows a vertical cross-sectional view of a PC member 11F, which is one of the first PC members, Fig. 3 shows a vertical cross-sectional view of a PC member 13A, which is one of the second PC members, and Fig. 4 shows a vertical cross-sectional view of a PC member 12, which is an intermediate PC member. In Fig. 1, the PC members 11A to 11F are shown to have the same outer diameter and inner diameter, but these are set appropriately as long as the laminate structure in Fig. 1 can be achieved, and they do not need to be equal. The same applies to the PC members 13A to 13I.

[0020] 2 shows the cross section of the PC member 11F, the cross-sectional structures of the PC members 11A to 11E are similar. However, as described above, the outer diameter and inner diameter may be slightly different, and may be different outside the ranges described here. The relationship between the PC member 13A and the PC members 13B to 13I is also similar.

[0021] In the PC member 11F (Fig. 2) which is the first PC member, twelve tendon through holes 20A-20L are formed along the circumferential direction. The tendon through holes are holes which penetrate the PC member 11F in the vertical direction (stacking direction), and accommodate the PC steel rods (tendons) 50 used in the tensioning work described below. Fig. 2 also shows an anchor plate 52 which is attached to the PC steel rods 50 during the tensioning work as described below. The PC members 11A-11E also have a similar configuration to that shown in Fig. 2, and when the PC members 11A-11F are stacked, the tendon through holes 20A-20L in all the PC members overlap in a plan view.

[0022] The second PC member 13A (Fig. 3) also has a tendon through-hole through which the PC steel bar 50 passes and which corresponds to that in the PC member 11F, and this tendon through-hole overlaps in plan view with the corresponding tendon through-hole in the PC members 11A to 11F below it. However, as shown in Fig. 3, the PC member 13A does not have the tendon through-holes 20B, 20D, 20F, 20H, 20J, and 20L in Fig. 2, and only has tendon through-holes 20A, 20C, 20E, 20G, 20I, and 20K.

[0023] On the other hand, the PC member 13A is provided with a large number of reinforcing bar through holes 21 in which reinforcing bars 60, which will be described later, are accommodated, instead of the tendon through holes 20B, 20D, 20F, 20H, 20J, and 20L. The reinforcing bar through holes 21 are arranged in groups of three in the circumferential direction between the locations corresponding to the unformed tendon through holes 20B, 20D, 20F, 20H, 20J, and 20L and the tendon through holes 20A, 20C, 20E, 20G, 20I, and 20K formed adjacent thereto, for a total of 36 reinforcing bar through holes 21. The reinforcing bar through holes 21 also penetrate the PC member 13A in the vertical direction, similar to the tendon through holes. 3, and when the PC members 13A-13I are stacked, the tendon through holes 20A, 20C, 20E, 20G, 20I, and 20K in all of the PC members overlap in a plan view. In the second stack 130, the reinforcing bar through holes 21 in each of the PC members communicate in the vertical direction, so that each reinforcing bar through hole 21 in FIG. 3 can accommodate a reinforcing bar 60 having a length approximately equal to the height of the second stack 130.

[0024] In the PC member 12 (Fig. 4) which is the intermediate PC member, tendon through holes corresponding to all of the tendon through holes 20A-20L in the PC member 11F (first PC member: Fig. 2) and reinforcing bar through holes corresponding to all (36) of the reinforcing bar through holes 21 in the PC member 13A (second PC member: Fig. 3) are provided. Therefore, in the laminated structure of Fig. 1, the tendon through holes 20A-20L in all of the PC members 11A-11F, 12 overlap in a plan view. Also, the tendon through holes 20A, 20C, 20E, 20G, 20I, 20K in all of the PC members 12, 13A-13I overlap in a plan view, and the reinforcing bar through holes 21 in all of the PC members 12, 13A-13I communicate in the vertical direction.

[0025] In addition, although each PC member has a cylindrical shape in Figures 2 to 4, it is not necessary for each PC member to be integrated into a cylindrical shape, and for example, the structure in Figures 2 to 4 may be divided into two parts, left and right. Also, other shapes, particularly those having a cross-sectional shape perpendicular to the vertical direction different from the above, may be appropriately used depending on the form of the structure to be constructed.

[0026] In the laminated structure of Fig. 1, a PC structure that does not use reinforcing bars is realized in the laminated structure of the first PC member (PC member 11A-11F) and the middle PC member (PC member 12) on the lower layer side, and a PPRC structure that uses reinforcing bars is realized in the laminated structure of the middle PC member (PC member 12) and the second PC member (PC members 13A-13I) on the upper layer side. The construction method in this case will be explained below.

[0027] Fig. 5 is a flow chart showing this construction method, and Fig. 6 and Fig. 7 are cross-sectional views showing the steps of this construction method in a simplified manner. As shown in Fig. 6(a), first, as a preparation step, a ground anchor 200 is installed at a construction point in the ground G by boring, and then a base frame 210 used to hold the PC member during construction on the ground is fixed to the ground anchor 200.

[0028] Next, as shown in Fig. 6(b), the PC member 11A, which is the lowest layer in Fig. 1, is fixed to the base frame 210 without inclination (S1 in Fig. 5). After that, as shown in Fig. 6(c), in this state, PC steel bars 50 and the like are placed in the tendon through holes 20A-20L (Fig. 2) of the PC member 11A as described later, and tensioning is performed on the PC member 11A to apply prestress along the vertical direction (S2 in Fig. 5). This tensioning is performed using 12 PC steel bars 50 corresponding to the tendon through holes 20A-20L. After that, grout is injected into each tendon through hole in the PC member 11A as described later and allowed to solidify.

[0029] Next, as shown in FIG. 6(d), an epoxy adhesive is applied to the upper surface of the PC member 11A as a bonding layer, and then the PC member 11B is laminated thereon (S3 in FIG. 5). At this time, the PC steel rod 50 is installed in the PC member 11B in the same manner as in the PC member 11A, and the PC steel rod 50 used in the lower PC member 11A side and the PC steel rod 50 used in the upper PC member 11B side are connected as described later. After that, as shown in FIG. 6(e), the PC member 11B is tensioned in the same manner as in FIG. 6(c) (S4 in FIG. 5), and then grout is injected into the tension member through hole 20 of the PC member 11B and allowed to solidify. As a result, the positional relationship between the PC member 11A and the PC member 11B is fixed with prestress applied to each of them.

[0030] Next, as shown in Fig. 6(f), the PC members 11A etc. are pressed into the ground G while the inside is excavated with a hammer grab (not shown) and set (S5 in Fig. 5). Thereafter, the same operations as those in Fig. 6(d)-(f) (S3-S5 in Fig. 5) are sequentially repeated for the PC members 11C-11F, and when a predetermined total number of first PC members (PC members 11A-11F) have been stacked (S6 in Fig. 5: Yes), the first stacked body 110 in Fig. 1 is formed (first stacking step).

[0031] Thereafter, similarly to the first PC member, the intermediate PC member 12 is also laminated (S7 in FIG. 5) and tensioned (S8 in FIG. 5), followed by pressing and sinking (S9 in FIG. 5). As a result, as shown in FIG. 6(g), with tensioning performed on each PC member, a first stack 110 is formed in the ground G, in which the PC members 11A-11F are stacked, and the PC member (intermediate PC member) 12 is fixed onto it.

[0032] Here, the prestress applied to the PC member in the tensioning work (Fig. 6(c)(e)) is, for example, 3.0 to 7.0 N / mm 2 This prestress value is a value required to ensure strength in the base portion of the structure 1 constructed by this construction method.

[0033] In the above work, PC steel rods 50 installed in the twelve tendon through holes 20A to 20L (Figure 2) in each of the PC members 11A to 11F, 12 are used, and as described below, the PC steel rods 50 are connected between adjacent PC members.

[0034] Next, as shown in Fig. 7(h), similarly to Fig. 6(d) (S3 in Fig. 5), an epoxy adhesive that will become a bonding layer is applied to the upper surface of the PC member 12, and then the upper layer PC member (second PC member) 13A is laminated (S10 in Fig. 5). At this time, as shown in Fig. 3, only six tendon through holes 20A, 20C, 20E, 20G, 20I, and 20K are provided in the PC member 13A, and PC steel rods 50 are installed in these tendon through holes, and these six PC steel rods 50 are connected to the PC steel rods 50 in the tendon through holes 20A, 20C, 20E, 20G, 20I, and 20K in the PC member 12 below. Also, each of the reinforcing bar through holes 21 in the PC member 12 (Fig. 4) communicates with each of the reinforcing bar through holes 21 in the PC member 13A (Fig. 3).

[0035] Next, as shown in FIG. 7(i), prestress is applied to the PC member 13A by tensioning using the PC steel rod 50 in the same manner as in FIG. 6(c)(e) (S11 in FIG. 5). After that, as shown in FIG. 7(j), the PC member 11A and the like are further pressed in and sunk in the same manner as in FIG. 6(f) (S12 in FIG. 5). The steps in FIG. 7(h)-(j) are sequentially repeated for the PC members 13B-13I, and the PC members up to the PC member 13I are stacked (S13 in FIG. 5: Yes), thereby forming the second stack 130 in FIG. 1 (second stacking step). As a result, a stacked structure is formed in the ground G in which the PC member 11A is provided in the lowest layer and the PC member 13I is provided in the uppermost layer, as shown in FIG. 7(k).

[0036] In the tensioning work (FIG. 7(i)), unlike the cases of FIGS. 6(c) and 6(e), only six PC steel bars 50 are used. Therefore, the prestress in this case is smaller than that in the cases of FIGS. 6(c) and 6(e), and is 0.5 to 1.0 N / mm 2This prestress value is the minimum required to perform the work shown in Figure 7.

[0037] In this state, the PC steel rods 50 in the tendon through holes 20A, 20C, 20E, 20G, 20I, and 20K of the PC members 12, 13A to 13I are connected to each other, and the reinforcing bar through holes 21 (FIGS. 3 and 4) in the PC members 12, 13A to 13I communicate with each other.

[0038] After that, the slime inside the cylindrical laminated structure is removed using a tremie pipe or a sand pump, and then concrete is poured at the bottom to form the bottom slab concrete layer 70, as shown in FIG. 8(l) (S14 in FIG. 5).

[0039] Next, as shown in FIG. 8(m), reinforcing bars 60 are stored and fixed in each of the reinforcing bar through holes 21 (FIGS. 3, 4) connected in the PC members 12, 13A to 13I (reinforcing bar installation process: S15 in FIG. 5). At this time, each of the reinforcing bar through holes 21 is filled with a filler (mortar) before solidification, and then the reinforcing bar 60 is stored and the filler is solidified, so that the reinforcing bar 60 is fixed in each reinforcing bar through hole 21. As shown in FIGS. 2 to 4, the reinforcing bar through holes 21 are formed only in the PC members 12 and the second laminate 130 (PC members 13A to 13I) on the upper layer side, and are not formed in the first laminate 110 (PC members 11A to 11F) on the lower layer side, so that the length of the reinforcing bar 60 corresponds to the height of the laminated structure of the PC members 12 and the second laminate 130, and is shorter than the height of the entire structure 1 (FIG. 1).

[0040] 8(n), after removing the moisture inside the laminated structure, soil is poured on top of the bottom slab concrete layer 70 inside to form a fill soil layer 71 (S16 in FIG. 5). In this way, the structure 1 in FIG. 1 is constructed.

[0041] Figure 9 is a cross-sectional view showing in detail the structure relating to the PC steel rod (tension member) 50 during the above-mentioned tensioning operation (Figure 6(e)), and shows a cross section along the vertical direction at the tension member through-hole 20A. Also shown here is a bonding layer 80 made of adhesive used when the PC member 11B was installed on the top of the PC member 11A (S3 in Figure 5). As mentioned above, after tensioning, the PC steel rod 50 etc. are fixed in the tension member through-hole 20 with grout, and the filling layer 90 made of this grout is also shown.

[0042] Here, PC steel rod 50A is used in lower PC member 11A, and PC steel rod 50B is used in upper PC member 11B. PC steel rods 50A, 50B are threaded, and nuts 51 are screwed onto them and attached from above. An anchor plate 52, which is a rectangular metal plate extending horizontally and through which PC steel rod 50 passes, is attached to the upper surfaces of PC members 11A, 11B. Correspondingly, recesses 52A are formed around tendon through holes 20A on the upper sides of PC members 11A, 11B, which are dug down so that anchor plate 52 does not protrude above the upper surfaces of PC members 11A, 11B when housed therein.

[0043] Therefore, the configuration shown in FIG. 9 is realized by attaching the nut 51 to the PC steel bars 50A and 50B above the anchor plate 52. At this time, the coupler 53, whose inner surface is threaded like the nut 51, is attached to the upper end of the PC steel bar 50A and the lower end of the PC steel bar 50B, so that the PC steel bar 50A and the PC steel bar 50B are joined and integrated. Therefore, by tightening the upper nut 51 in FIG. 9, prestress can be applied in the vertical direction to the PC member 11B via the PC steel bar 50B. As described above, the lower end side of the lower PC steel bar 50A is fixed to the PC member 11A outside the illustrated range, and by tightening the lower nut 51 in FIG. 9 in the tensioning work before this stage, prestress is similarly applied in the vertical direction to the PC member 11A. 9 shows the cross-sectional structure of the tendon through-hole 20A, but the other tendon through-holes have similar structures, and by tightening the nuts 51 to the PC steel bars 50 in all the tendon through-holes with a common torque, it is possible to apply a uniform prestress within the plane. As described above, this prestress is, for example, 3.0 to 7.0 N / mm 2 The range is said to be as follows.

[0044] 9, the PC members 11A, 11B are formed with grout injection holes 54, which are small holes that connect the tendon through-holes 20A with the outside on the side. Therefore, after prestressing is applied by tightening the nuts 51, highly fluid liquid grout is injected through the grout injection holes 54 and allowed to solidify, thereby forming a filling layer 90 and fixing the PC steel bars 50A, 50B in the tendon through-holes 20A.

[0045] The structure in Fig. 9 is the same for other connection points in the first laminate 110, and this structure is used to stack and tension each PC member. The same is true for the connection points between the PC member 12 and the PC member 13A in Fig. 7(i) and the connection points in the second laminate 130, but as mentioned above, in this case the number of tendon through holes (PC steel bars) used is small, and the prestress is 0.5 to 1.0 N / mm as mentioned above. 2It is set to a small degree.

[0046] FIG. 10 is a view showing a cross section along the vertical direction around the reinforcing bar through hole 21 in the PC members 13H and 13I when the reinforcing bar 60 is inserted and fixed in FIG. 8(m). As described above, the reinforcing bar through hole 21 in the lower PC member 13H and the reinforcing bar through hole 21 in the upper PC member 13I communicate with each other, and a common reinforcing bar 60 is provided inside the reinforcing bar through hole 21. As described above, the reinforcing bar 60 is installed after the reinforcing bar through hole 21 is filled with mortar as a filler before solidification, so that a filling layer 91 of solidified mortar is formed around the reinforcing bar 60 in the reinforcing bar through hole 21. That is, the reinforcing bar 60 is fixed in the second stack 130 by the structure of FIG. 10. Note that a single reinforcing bar 60 is used in FIG. 10, but in reality, a reinforcing bar 60 may be integrated by connecting a plurality of reinforcing bars using joints. However, unlike the PC steel members 50A and 50B in FIG. 9, even in such a case, the reinforcing bars are already integrated together at the time of installation in FIG. 8(m) (before the mortar hardens).

[0047] As described above, the filling layer 90 in Fig. 9 is formed by injecting grout through the grout injection hole 54 after tensioning and allowing it to solidify, and this operation is performed for each individual PC member. Therefore, grout is injected after the PC steel rod 50 is fixed to each PC member by the nut 51, anchor plate 52, etc. At this time, it is also easy to visually check whether grout has been filled into the tendon through-hole 20A, etc. in a single PC member.

[0048] In contrast, when forming the filled layer 91 in Fig. 10, the total depth of the reinforcing bar through holes 21 that are connected in the stacking direction corresponds to the stacking structure of the PC member 12 and the PC members 13A to 13I, and is about 10 times as deep as the tendon through hole 20A in the above case. For this reason, when mortar is injected after inserting the reinforcing bar 60 into the reinforcing bar through hole 21 as in the case of the PC steel rod 50, for example, it is not easy to confirm whether the reinforcing bar through hole 21 is filled with mortar. For this reason, the filled layer 91 in Fig. 10 is formed by forming the second stack 130 on the PC member 12 (Fig. 8(l)), injecting mortar into each reinforcing bar through hole 21 that is connected between them from above, inserting the reinforcing bar 60 from above, and then solidifying it.

[0049] In this case, if the reinforcing bar 60 is long and the reinforcing bar through hole 21 is deep, the mortar will harden and it will be difficult to install the reinforcing bar 60 unless the work of inserting the reinforcing bar 60 into the reinforcing bar through hole 21 is performed quickly. This is also true in the case where the reinforcing bar 60 is integrated using a joint as described above. This becomes more noticeable when the PPRC structure is applied to a structure that is long in the vertical direction.

[0050] In the above-mentioned structure 1, by using the PPRC structure (second laminate 130) only on the upper layer side where large horizontal stress is applied after construction, and using the PC structure (first laminate 110) on the lower layer side, it is possible to shorten the reinforcing bars 60 or the reinforcing bar through holes 21, facilitating the installation of the reinforcing bars 60 and facilitating the construction work of this structure 1. Also, since the overall length of the reinforcing bars 60 can be shortened, it becomes unnecessary to use joints, which also makes the work easier and faster.

[0051] In this case, by setting a large prestress on the lower layer side, it is possible to maintain high strength of the first laminate 110. In addition, by using the intermediate PC member 12 that is compatible with both PC and PPRC structures, it becomes particularly easy to combine the first laminate 110 and the second laminate 130.

[0052] In the above example, cylindrical PC members (first PC member, second PC member, intermediate PC member) whose cross-sectional structures are shown in Figures 2 to 4 were used, and each layer in Figure 1 was composed of each of these PC members alone. However, if the structure is large in the horizontal direction, the PC members in each layer may be divided in the horizontal direction and each layer of the structure may be formed by combining multiple divided PC members. Specifically, if the outer diameter of the structure 1 (each PC member) is about 3800 mm or more, it is preferable to use such a divided structure, and if the outer diameter is 3500 mm or less, it is preferable to use an undivided integrated structure.

[0053] In this case, for example, each of the PC members in Figs. 2 to 4 may be divided into two parts, left and right, and used. Even in this case, stacking (S3, S7, S10 in Fig. 5) and tensioning (S4, S8, S11) can be performed for each divided PC member, and pressing and sinking (S5, S9, S12) can be performed after each layer is formed. In other words, the above construction method is not limited to the case where each layer is composed of a single PC member. Even in this case, the installation of reinforcing bars can be performed in the same manner after all the PC members have been stacked (after the second stack has been formed).

[0054] In the above example, the PC well method using the PC members is described, and the structure constructed by this method is obtained by sinking it into the ground G. In this case, since it is necessary to handle particularly large horizontal stress only on the upper side, the reinforcing bar 60 is used only on the upper side. The same requirement is also valid for structures that are not pressed (sunk) into the ground. In other words, the above construction method is valid not only for the PC well method, but also for all PC methods that build structures by stacking PC members. In this case, it is not necessary for the structure or the PC members to have a cylindrical structure.

[0055] In addition, in the PC Well method, the structure in which the PC members are stacked is cylindrical and hollow inside. As long as the inside can be made hollow in this way, the outer shape of the PC member can be set appropriately. For example, the cross-sectional shape perpendicular to the vertical direction of the outer shape can be set appropriately according to the cross-sectional shape of the structure to be constructed, such as an ellipse, an oblong shape, or an (approximately) rectangular shape. Even in this case, it is easy to form multiple tendon through-holes and rebar through-holes distributed around the central axis, as described above.

[0056] In addition, in Figs. 2 to 4, as the simplest example, the tendon through-holes and the reinforcing bar through-holes are arranged on the circumference at almost equal intervals with a constant distance from the center, but they may be arranged in other configurations. For example, in Figs. 2 to 4, they may be arranged on the circumferences of two circles (first circle, second circle) with different distances from the center. Alternatively, in this case, the tendon through-holes or the reinforcing bar through-holes may be arranged in a staggered arrangement such that the tendon through-holes or the reinforcing bar through-holes are alternately present on the first circle and the second circle along the circumferential direction, or they may be arranged similarly on the circumferences of more circles. Even when the external shape of the cross-sectional shape of the PC member (structure) is not circular, the tendon through-holes and the reinforcing bar through-holes can be arranged in the same manner along the external shape of the cross-sectional shape. In this case, the tendon through-holes are formed in a dispersed manner so that the tendon can apply a uniform prestress, and the reinforcing bar through-holes are formed in a manner so that the strength can be uniformly increased by the reinforcing bar.

[0057] In the above example, an intermediate PC member 12 different from the first PC member and the second PC member was used between the first laminate 110 and the second laminate 130. However, for example, a PC member having the same structure as the second PC member can also be used as the intermediate PC member. In this case, for example, some of the rebar through holes in the second PC member can be used as tendon through holes in the relationship with the first laminate. In such a case, it is possible to realize a similar structure without substantially using an intermediate PC member.

[0058] The present invention has been described above based on the embodiment. This embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in the combination of the respective components, and that such modifications are also within the scope of the present invention. [Explanation of symbols]

[0059] 1 structure 11A~11F First PC member (First precast member: PC member) 12 Intermediate PC member (Intermediate precast member: PC member) 13A~13I Second PC member (Second precast member: PC member) 20A~20L tension material through hole 21 Reinforced concrete through hole 50, 50A, 50B PC steel bar (tension material) 51 Nut 52 Anchor Plate 52A Recess 53 Coupler 54 Grout injection hole 60 Steel Bar 70 Bottom concrete layer 71 Filled soil layer 80 Bonding layer 90, 91 packed bed 110 First laminate 130 Second laminate 200 Ground Anchor 210 Base Frame G. Ground

Claims

1. A method for constructing a structure using precast members, comprising the steps of: installing a structure in which a plurality of precast members are stacked after tensioning work has been performed by attaching a tension member; and constructing the structure by submerging the structure; The precast members include: A first precast member having a plurality of tendon through holes through which the tendons pass along the stacking direction; A second precast member having a plurality of tendon through holes, the number of which is smaller than that of the first precast member, and a plurality of reinforcing bar through holes through which reinforcing bars are inserted along the stacking direction; Each of these is provided multiple times. a first stacking step of installing the tendons in the tendon through-holes to obtain a first stack in which the first precast members are stacked in a state in which the tensioning operation has been performed, and then sinking the first stack; a second stacking step of stacking the second precast members on the first stack so that the reinforcing bar through holes of the second precast members are connected in the stacking direction, and the second stack is further stacked on the first stack to obtain a second stack in which the reinforcing bar through holes of the second precast members are connected in the stacking direction, and sinking the first stack and the second stack; a reinforcing bar installation process for inserting and fixing the reinforcing bar into each of the reinforcing bar through holes that are connected in the stacking direction in the second stack so as to overlap with all of the second precast members in the stacking direction and not overlap with the first stack; A method for constructing a structure using precast members, comprising:

2. Between the first stack and the second stack, providing an intermediate precast member having a plurality of tendon through holes corresponding to the tendon through holes in the first precast member and a plurality of reinforcing bar through holes corresponding to the reinforcing bar through holes in the second precast member; In the second stacking step, the second precast members are stacked so that the reinforcing bar through holes in the intermediate precast member and all of the second precast members are connected in the stacking direction; In the reinforcing bar installation step, the reinforcing bars are inserted into and fixed to each of the reinforcing bar through holes so as to overlap all of the second stacks and the intermediate precast members in the stacking direction.

2. A method for constructing a structure using precast members according to claim 1.

3. 3. A method for constructing a structure using precast members, as described in claim 1 or 2, characterized in that the value of prestress applied to the second precast member by the tensioning operation in the second stacking process is set to be smaller than the value of prestress applied to the first precast member by the tensioning operation in the first stacking process.

4. A method for constructing a structure using precast members, as described in any one of claims 1 to 3, characterized in that the first precast member and the second precast member both have a cylindrical shape with a central axis parallel to the stacking direction, and the multiple tendon through holes and the multiple reinforcing bar through holes are formed in the cylindrical shape and distributed in the circumferential direction around the central axis.

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