JP2019148108A - Bridge pier construction method - Google Patents

Abstract

[Problem] To provide a method for constructing bridge piers that can shorten the construction period of bridge construction. [Solution] A plurality of panel members 30 made of precast concrete having an outer panel 34, an inner panel 35, and a connecting panel 36 and with an integrated reinforcing bar cage 38 are prepared (step ST1), and the outline of a column main body 8 is prepared. A plurality of panel members 30 are arranged along with a gap 41 at at least one location in the circumferential direction (step ST12), and concrete is poured into the closed space 37 other than the part where the gap 41 is provided (step ST14). ), this is repeated to construct the column body intermediate body 48 which is an unfinished state of the column body part 8 in which the gap 41 is extended upward (step ST2), and the column head 9 is placed on the column body intermediate body 48. is constructed (step ST3), and the gap 41 of the column body intermediate body 48 is closed to complete the column body portion 8 (steps ST4, ST7). [Selection diagram] Figure 9

Description

  The present disclosure relates to a method for constructing a pier having a column main body and a column head.

  Large reinforced concrete piers may be constructed in valleys in mountainous areas. Such piers need to be constructed in a vertical direction by repeatedly building a concrete structure of a predetermined height on the foundation for each lift, so that construction takes time and the cross-sectional dimensions are large. Become. Therefore, in recent years, a half precast method using precast concrete for the outer peripheral surface portion of the pier and using this as a formwork is increasing.

  In addition, when building a pier for each lift, it is necessary to connect the main reinforcing bars extending in the vertical direction, and it takes time to assemble the band reinforcing bars and the intermediate band reinforcing bars. Therefore, a precast concrete panel member that forms the surface of the pier surface is pre-embedded with a strip reinforcement and intermediate strip reinforcement, and the panel pier under construction in which main reinforcement with a length equivalent to multiple lifts is built. The present applicant has developed a SPER method that repeatedly performs the work of building up and the work of placing concrete inside the panel member (see Non-Patent Document 1). The SPER method can save labor for rebar assembling work on site, so the construction period can be greatly shortened.

[Online], search on December 1, 2016, Internet (URL: http://www.smcon.co.jp/service/sper/)

  By the way, when a pier is provided in a river, a lake, the sea, etc., a pier may be built on a steel pipe sheet pile well foundation. In addition, there is a case where a beam for supporting a steel pipe sheet pile well is required in the part where the pier is constructed. In such a case, the lower part of the pier is built to a height lower than that of the cut beam, and the side pressure of the steel pipe sheet pile cannula is reduced by backfilling or pouring water into the steel pipe sheet pile well, and then the pier is removed after removing the cut beam. You can complete the pier by restarting the construction. However, if such a procedure is taken, since the superstructure of the bridge can be started only after the pier is completed, even if the SPER method described in Non-Patent Document 1 is used, the construction period of the bridge work is prolonged. Unavoidable.

  In view of such a background, it is an object of the present invention to provide a method for constructing a pier that can shorten the construction period of bridge work.

  In order to solve such a problem, an aspect of the present invention is to construct a pier (2) having a column main body (8) and a column head (9) disposed on the column main body. A pier construction method comprising an outer panel (34), an inner panel (35), and a connecting portion (36) for connecting the outer panel and the inner panel, and a plurality of strip reinforcing bars (32) and a plurality Preparing a plurality of panel members (30) made of precast concrete integrated with reinforcing bar rods (38) including intermediate band reinforcing bars (33) (ST1), at least along the contour of the column main body and A step (ST12) of arranging a plurality of the panel members with a gap (41) in one circumferential direction, and the gap closed by the outer panel, the inner panel and at least two of the connecting portions are provided. The step of placing concrete in the closed space (37) other than the formed portion (ST14), the step of arranging the panel members, and the step of placing concrete in the closed space become the height of the column main body. Step (ST2 (ST11-ST16)) of constructing the column body intermediate body (48) which is the unfinished state of the column body portion with the gap extended upward, and the top of the column body intermediate body The step of building the column head (ST3), and the step of completing the column main body by filling the gap of the column main body intermediate below the column head (ST4, ST7). It is characterized by.

  According to this configuration, after the pillar main body intermediate with the gap extended upward is constructed, the pillar head is constructed on the pillar main body intermediate, so that it is performed on or protrudes from the column head The superstructure of the bridge can be started before the pier work is completed. As described above, the construction for completing the column main body is not critical and may be performed in parallel with the superstructure, so that the construction period of the bridge construction can be shortened.

  In the above configuration, the step (ST4, ST7) of completing the column main body (8) is performed by using the reinforcing bars (32) of the panel member (30) disposed on both sides of the gap (41). Steps (ST31, ST43) connected to each other via a joint unit (43), and the inner panel (35) and the outer panel (34) of the panel member arranged on both sides of the gap are closed. , A step of assembling a precast concrete joint panel (ST32, ST44) which forms the periphery of the formwork (50) or the column main body, and placing concrete in the gap closed by the formwork or the joint panel (ST33, ST45).

  According to this configuration, even if the column head is constructed before the column main body is completed, the column main body can be completed after the belt reinforcing bars are continuous in the circumferential direction.

  Moreover, in the said structure, the step (ST3) which builds the said column head (9) assembles the connection main rebar (31D) extended below from the said column head and arrange | positioned in the said clearance gap (41) ( The step (ST7) of completing the column main body portion (8) including ST25) may further include a step (ST42) of extending the main reinforcing bar (31) and connecting to the connecting main reinforcing bar.

  According to this configuration, even if the column head is constructed before the column main body is completed, the column main body can be completed after the main reinforcing bars are continued in the vertical direction.

  In the above configuration, at least one beam (22) is provided in a portion where the column main body (8) is constructed, and the gap (41) is in plan view with respect to each beam. Steps (ST6) for removing the at least one beam after the step (ST3) for constructing the column head (9), provided at two locations in the circumferential direction passing through the column main body (8). The step (ST4, ST7) of completing the column main body portion includes the step of assembling the formwork (50) or the joint panel (ST32) in a space lower than the at least one beam. In the space where the step of placing concrete in the gap (ST33) and filling the lower part of the gap (ST4), and the space where the at least one beam is removed, the formwork May includes a step (ST7) for filled between the upper portion of the gap by performing a step (ST45) for concrete is in the step (ST44) and the gap of assembling the joint panel.

  According to this configuration, the column head can be constructed on the column main body constructed in a state where the cutting beam remains. That is, the removal work of the cut beam is not critical, and the construction period of the bridge work can be shortened. Further, the pillar main body portion can be completed by gradually filling the gap while removing the beam.

  Moreover, in the said structure, the step (ST4) which fills the lower part of the said gap | interval is good to be performed after the step (ST3) which builds the said column head.

  The step of filling the lower part of the gap can be constructed together with, for example, the construction of the column body intermediate before the step of constructing the column head, since the beams do not interfere with each other. According to this, the column main body intermediate can be constructed quickly and the column head can be constructed earlier.

  Moreover, in the said structure, the said pier (2) is constructed | assembled on the steel pipe sheet pile well foundation (10), and before the step (ST6) which removes the said cut beam (22), the said lower part of the said cut beam After the first backfilling step (ST5) of backfilling or pouring the earth and sand around the pier and the step of filling the lower part of the gap (ST4), the second backfilling or pouring the earth and sand around the pier A backfilling step (ST8) may be further included.

  According to this configuration, even if the pier is constructed on a steel pipe sheet pile well foundation, it is possible to safely remove the beam while performing backfilling step by step.

  Thus, according to this invention, the construction method of the pier which can shorten the construction period of bridge construction can be provided.

Side view of a bridge constructed by applying the method according to the embodiment Front view of the bridge constructed by applying the method according to the embodiment 1 is a cross-sectional view showing a state before the foundation pier construction shown in FIG. The top view which shows the state before construction of the pier of the foundation shown in FIG. Front view showing the construction allocation of the pier shown in FIG. Plan view showing the construction assignment of the pier shown in FIG. Detailed plan view of the pier end shown in FIG. Detailed plan view of the middle part of the pier shown in FIG. The flowchart which shows the procedure of the pier construction method which concerns on embodiment Flow chart showing the procedure of the pillar body intermediate construction work shown in FIG. Front view of the pier with the pillar body intermediate construction completed Flow chart showing the procedure of the pillar head construction work shown in FIG. Front view of the pier after the construction of the column head has been completed FIG. 9 is a flowchart showing the procedure of the gap lowering process shown in FIG. Front view of the pier after the gap clearance is complete FIG. 9 is a flowchart showing the procedure of the upper gap filling process shown in FIG. Front view of the pier in the state where the gap gap filling work has been completed

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a side view of a bridge 1 constructed by applying the method according to the embodiment, and FIG. 2 is a front view thereof. As shown in FIG. 1 and FIG. 2, the bridge 1 is constructed so that the bridge girder 3 is continuous over a plurality of spans between three or more abutments arranged so as to be separated from each other in the direction of the bridge axis, and support stands such as the pier 2. Is a multi-girder continuous bridge of continuous girder type.

  The bridge girder 3 is supported by the pier 2 via a support 4 and is a continuous box girder made of concrete in which an upper floor slab 5 and a lower floor slab 6 are connected by a plurality of webs 7. In the illustrated example, the bridge girder 3 is a multi-box girder having four webs 7 spaced in the direction perpendicular to the bridge axis. The two webs 7 arranged at both ends are inclined so as to expand upward, and the two webs 7 arranged at the center respectively extend in the vertical direction. The two webs 7 arranged at both ends have a lower end connected to an end portion of the lower floor slab 6 in the direction perpendicular to the bridge axis and an upper end joined to an intermediate portion of the upper floor slab 5 in the direction perpendicular to the bridge axis. The upper floor slab 5 is formed wider than the lower floor slab 6 and protrudes laterally from the web 7. The width of the lower floor slab 6 and the pair of webs 7 is smaller than the width of the pier 2, and the width of the upper floor slab 5 is larger than the width of the pier 2.

  In another embodiment, the bridge girder 3 may be separated into a portion corresponding to the left span of the pier 2 and a portion corresponding to the right span, and is rigidly coupled to the pier 2 without the support 4. May be. The bridge girder 3 may be a single box girder having two webs 7.

  The pier 2 has an oblong, generally constant cross-sectional shape that is long in a direction perpendicular to the bridge axis, and has a substantially hollow column main body 8 and a solid structure disposed on the column main body 8. It has a column head 9. The pier 2 is constructed of reinforced concrete on the foundation 10 constructed in the ground G.

  In this specification, the term "constructed by reinforced concrete" means not only reinforced concrete structures in which concrete is reinforced by reinforcing bars, but also PC steel wires, PC cables, steel materials, steel fibers, carbon fibers, aramid fibers, and aramids. Including those containing muscles. The term “consisting of concrete” does not mean that it is composed of concrete alone, but includes concrete as a structural body. It is a reinforced concrete structure, a prestressed concrete structure reinforced with PC steel wire or PC cable, or steel fiber. Or a structure reinforced with carbon fiber, aramid fiber, aramid muscle, or the like.

  The substantially hollow structure means that the column main body 8 is composed of a solid column base 8A and a hollow column 8B constructed on the column base 8A. In the present embodiment, four hollow spaces that are separated from each other and arranged in a row in a direction perpendicular to the bridge axis are formed in the column portion 8B. In other words, the pillar body portion 8 of the pier 2 includes an outer peripheral wall 8C having an outer contour at the pillar portion 8B and three intermediate walls integrally formed so as to extend in the bridge axis direction inside the outer peripheral wall 8C. 8D.

  In other embodiments, the entire column main body 8 may have a solid structure. In this case, the column head 9 indicates the upper end portion of the pier 2 that supports the bridge girder 3 via the support 4. In other embodiments, the column head 9 may have a larger cross-sectional shape than the column main body 8. When the bridge girder 3 is rigidly connected to the pier 2 as described above, the upper end portion of the pier 2 overhanging from the bridge girder 3 (which can be said to be a portion of the continuous bridge girder 3 disposed on the pier 2) is the column head 9. The part below the column head 9 of the pier 2 forms the column main body 8. Also in this case, the column main body 8 may have a substantially hollow structure or a solid structure.

  FIG. 3 is a cross-sectional view showing a state before the pier of the foundation 10 shown in FIG. 1 is constructed, and FIG. 4 is a plan view thereof. The pier 2 is indicated by an imaginary line. As shown in FIG. 3 and FIG. 4, the foundation 10 is a steel pipe sheet pile well foundation constructed in a river, and a plurality of steel pipe sheet piles 11 arranged in a ring shape on the outer peripheral edge, and a plurality of steel pipes. Inside the sheet pile 11, there is provided a spread sand 12, a bottom concrete 13 and a top concrete 14 constructed in order from the bottom. The steel pipe sheet piles 11 adjacent to each other are connected to each other by a joint 15 (only a part of which is shown in FIG. 4) subjected to a water stop treatment, and a plurality of steel pipe sheet piles 11 form a closed annular steel pipe sheet pile well 16. Yes. In this embodiment, the steel pipe sheet pile well 16 is formed in an oval shape that is long in the direction perpendicular to the bridge axis in plan view. Filled concrete 17 (FIG. 3) is constructed in portions corresponding to the top slab concrete 14, the bottom base concrete 13, and the laying sand 12 in each steel pipe sheet pile 11. The top slab concrete 14 is provided at a position where the bottom surface and the top surface are lower than the existing ground line 19 below the water surface 18.

  The steel pipe sheet pile well 16 functions as a retaining wall when the pier 2 is constructed on the top concrete 14 inside thereof. After the construction of the pier 2, the steel pipe sheet pile well 16 is cut at a height near the upper surface of the top slab concrete 14, the upper part is removed, and the remaining lower part is a part of the foundation 10 shown in FIGS. Become. While the steel pipe sheet pile well 16 functions as a retaining wall, earth pressure and water pressure act on the steel pipe sheet pile well 16 from the outside. Therefore, a support 20 made of H-section steel is provided inside the steel pipe sheet pile well 16. In the present embodiment, the pier 2 is constructed in a state where the two-stage support works 20 are provided at positions having different heights.

  The support 20 is provided with three or more stages (for example, five stages) when excavating and draining the inside of the steel pipe sheet pile 16 for the construction of the top concrete 14. After the construction of the top slab concrete 14, the lower stage support 20 which has become unnecessary has been removed, and when the pier 2 is constructed, the upper two stages of support that cannot be removed until water is poured inside the steel pipe sheet pile 16 The work 20 is left.

  Each supporter 20 includes an annular oval flank 21 provided inside the steel pipe sheet pile cannula 16, and a plurality of (in this embodiment) extending in the flank 21 and extending in the bridge axis direction. 4) and a plurality of fires 23. The flank 21 is arranged with the pair of flanges facing inward and outward, and supports the steel pipe sheet piles 11 from the inside by filling the space between the steel pipe sheet piles 11. The cut beam 22 is arranged with a pair of flanges facing up and down, and is joined to the inner peripheral surface of the flank 21 to prevent deformation of the flank 21. The fire struck 23 is obliquely joined to the cut beam 22 and the protuberance 21 on both the left and right sides of both ends of the cut beam 22. Four cutting beams 22 are provided in each stage, and a total of eight cutting beams 22 pass through the space for constructing the pier 2.

  Next, the construction method of the pier 2 will be described.

  In the present embodiment, in order to shorten the construction period, the pier 2 is constructed by the above SPER method in which the pier surface is formed by a plurality of precast concrete panel members 30 (30A, 30B) formed so as to embed the band rebar 32 in advance. To do. FIG. 5 is a front view showing construction assignment of the pier 2 shown in FIG. 1, and FIG. 6 is a plan view thereof. As shown in FIG. 5, the pier 2 is planned to perform concrete placement into the inside of the panel member 30 in six times (divided into six lifts). The height of concrete for one lift is planned to be approximately 5 m (for example, 5.4 m), and the height of the panel member 30 is planned to be one lift by stacking the panel members 30 in a plurality of stages. The In the present embodiment, the height of the three-stage panel member 30 corresponds to the height of one lift.

  As shown in FIG. 6, the panel member 30 at each stage is planned to be divided into five at four locations corresponding to the hollow space in the direction perpendicular to the bridge axis. The two pier end portions provided at both ends do not include the intermediate wall 8D, and the three pier intermediate portions provided in the intermediate portion include the intermediate wall 8D. These division positions are aligned with the beam 22 in plan view. In other words, it is planned that the position of the temporary cutting beam 22 matches the division position of the panel member 30 (the position of the hollow space). In the present embodiment, the three pier intermediate portions have the same shape and the same size, and the two pier end portions have the same shape and the same size.

  Furthermore, the panel member 30 at each stage is planned to be divided into two in the bridge axis direction due to the limitation of the size that can be transported by the trailer and the limitation of the lifting load of the lifting equipment. The two panel members 30 divided in the bridge axis direction have rotational symmetry and are substantially the same. That is, each step of the pier 2 is configured by a total of ten panel members 30 including four corner panel members 30A having an arc shape of approximately ¼ circle and six intermediate panel members 30B having a T shape. The

  7 is a detailed plan view of the pier end shown in FIG. 6, and FIG. 8 is a detailed plan view of the middle part of the pier shown in FIG. As shown in FIGS. 7 and 8, in the pier 2 (in the concrete), there are a plurality of main reinforcing bars 31 (31A, 31B, 31C) extending vertically and a plurality of horizontally arranged annular members. A belt reinforcing bar 32 (32A, 32B, 32C) and a plurality of intermediate belt reinforcing bars 33 (33A, 33B, 33C) that are arranged at predetermined intervals along the circumferential direction of the pier 2 and extend horizontally are arranged. Yes.

  Specifically, a plurality of first main reinforcing bars 31A are arranged along the outer peripheral surface of the pier 2 and a plurality of second main reinforcing bars 31B are arranged inside the first main reinforcing bar 31A, and the inner peripheral surface of the pier 2 and A plurality of third main reinforcing bars 31C are arranged along the outer surface of the intermediate wall 8D (FIG. 8). On the outer peripheral side of the first main reinforcing bar 31A, a plurality of first strip reinforcing bars 32A arranged at predetermined intervals in the vertical direction are arranged so as to surround the first main reinforcing bar 31A. On the outer peripheral side of the second main reinforcing bar 31B, a plurality of second band reinforcing bars 32B arranged at predetermined intervals in the vertical direction are arranged so as to surround the second main reinforcing bar 31B. On the inner peripheral side of the third main reinforcing bar 31C, a plurality of third strip reinforcing bars 32C arranged at predetermined intervals in the vertical direction are arranged so as to be surrounded by the third main reinforcing bar 31C.

  At the position where the intermediate wall 8D (FIG. 8) of the bridge pier 2 is provided, a plurality of first intermediate strip reinforcing bars 33A that are arranged in the vertical direction with a predetermined interval and extend in the bridge axis direction are the first main front and rear. The reinforcing bars 31A are arranged so that the ends thereof are locked and bridged between them. At a position where the intermediate wall 8D of the pier 2 is not provided, a plurality of second intermediate band reinforcing bars 33B arranged at predetermined intervals in the vertical direction are arranged at predetermined positions in the circumferential direction of the pier 2 at the first band reinforcing bar. 32A and the 3rd belt | strand reinforcement 32C are made to latch over an edge part, and it is spanned over them. Inside the intermediate wall 8D (FIG. 8), a plurality of third intermediate strip rebars 33C that are arranged at a predetermined interval in the vertical direction and extend in the direction perpendicular to the bridge axis are left and right at a predetermined position in the bridge axis direction. The first intermediate band reinforcing bar 33A is engaged with the end portion of the reinforcing bar 33A.

  As shown in FIG. 7, the corner panel member 30 </ b> A includes an outer panel 34, an inner panel 35, and a plurality of connection panels 36 each made of concrete. The outer panel 34 forms the outer peripheral surface of the pier 2, and the inner panel 35 forms the inner peripheral surface of the pier 2. The connection panel 36 connects the outer panel 34 and the inner panel 35, and cooperates with the outer panel 34 and the inner panel 35 to form a closed space 37 that is closed in a plan view inside the corner panel member 30 </ b> A. doing. Further, the corner panel member 30A is manufactured as a precast product in which a reinforcing bar 38 formed by assembling a plurality of band reinforcing bars 32 and a plurality of intermediate band reinforcing bars 33 is integrally provided. The band reinforcement 32 protrudes in the circumferential direction from the circumferential edge of the adjacent outer panel 34 or inner panel 35 so that the mechanical joint 39 can be provided.

  As shown in FIG. 8, the intermediate panel member 30 </ b> B includes an outer panel 34 made of concrete, two inner panels 35, and a plurality of connection panels 36. The outer panel 34 forms the outer peripheral surface of the pier 2 and the inner panel 35 forms the inner peripheral surface of the pier 2 and the outer surface of the intermediate wall 8D. The connection panel 36 connects the outer panel 34 and the inner panel 35, or connects the two inner panels 35, and cooperates with the outer panel 34 and the inner panel 35 to form a flat surface inside the intermediate panel member 30B. A closed space 37 that is closed in view is formed. Further, the intermediate panel member 30B is manufactured as a precast product in which a reinforcing bar bar 38 formed by assembling a plurality of band reinforcing bars 32 and a plurality of intermediate band reinforcing bars 33 is integrally provided. The band reinforcing bar 32 and the first intermediate band reinforcing bar 33A protrude in the circumferential direction from the circumferential edge of the adjacent outer panel 34 or inner panel 35 so that the mechanical joint 39 can be provided.

  The main reinforcing bar 31 is provided so as to extend upward from the top slab concrete 14, is added at an appropriate position and extended upward, and is not included in the reinforcing bar 38. . The main reinforcing bar 31 is arranged in advance at a predetermined position before the panel member 30 is suspended and arranged at an appropriate position, and is inserted into the panel member 30 from below so as to have the above arrangement. In the present embodiment, the main reinforcing bar 31 protrudes from the top concrete 14 slightly longer than the height of one lift, and the main reinforcing bars 31 having a length corresponding to the height of two lifts are sequentially added to the column head 9. It is connected to a connecting main reinforcing bar 31D (see FIG. 13) provided so as to protrude downward from the lower end of the column head 9.

  The band reinforcing bars 32 of the panel members 30 adjacent to each other in the bridge axis direction are connected to each other by a mechanical joint 39. Further, the first intermediate band reinforcing bars 33 </ b> A are connected to each other by an intermediate band reinforcing bar joint unit 42 in which two mechanical joints 39 are provided at both ends of the short intermediate band reinforcing bar 33. A concrete panel (34, 35) is not provided at a position where the mechanical joint 39 and the intermediate band reinforcing bar joint unit 42 are arranged. In this embodiment, the joint panel 40 made of concrete that forms the periphery of the pier 2 is used. Is provided to block between the concrete panels. Thereby, the closed space 37 is also formed between the panel members 30 adjacent to each other in the bridge axis direction. In another embodiment, instead of providing the joint panel 40, a formwork may be assembled to close between the concrete panels.

  As shown in FIG. 3 and FIG. 4, the four cut beams 22 in total of 4 × 2 stages are provided so as to pass through the space for constructing the pier 2. Therefore, as shown in FIG. 6, the panel member 30 is arranged so that the gap 41 is formed at the position where the cut beam 22 is provided in plan view. Here, the arrangement so that the gap 41 is formed means that the strip reinforcing bars 32 of the panel members 30 adjacent to each other are separated from each other with a dimension larger than the width of the cut beam 22. As shown in FIG. 7 and FIG. 8, the band reinforcing bars 32 of the panel members 30 adjacent to each other in the direction perpendicular to the bridge axis are provided with two mechanical joints 39 at both ends of the short band reinforcing bar 32 arranged in the gap 41. They are connected to each other through the band reinforcing bar joint unit 43.

  FIG. 9 is a flowchart showing a procedure of the pier construction method according to the embodiment. As shown in FIG. 9, the construction of the pier 2 is performed as follows. That is, a necessary number of panel members 30 having the above-described configuration are manufactured and prepared in a factory or a yard (step ST1). Thereafter, a pillar body intermediate construction work for constructing the pillar body intermediate 48 (see FIG. 11) is performed (step ST2).

  FIG. 10 is a flowchart showing a procedure of the pillar body intermediate construction work shown in FIG. 9. As shown in FIG. 10, in the pillar body intermediate construction work, the number of steps of the panel members 30 to be stacked is a predetermined lift level that requires assembly of the main reinforcing bars 31 (in this embodiment, the second, fourth, and sixth lifts). If not (step ST11: No), the one-stage panel members 30 are arranged at predetermined positions so that a gap 41 is formed between those adjacent in the direction perpendicular to the bridge axis (step ST12). . If the number of steps of one lift (three steps in this embodiment) is not reached (step ST13: No), the operation of step ST12 is repeated, and the panel members 30 are stacked up to three steps that are the number of steps of one lift. At this time, for the panel members 30 adjacent to each other in the bridge axis direction, the reinforcing bars are connected to each other by the mechanical joint 39 (FIG. 7) or the intermediate strip reinforcing bar joint unit 42 (FIG. 8), and then the joint panel 40 is arranged to reinforce the reinforcing bars. The connecting portion is closed to form a closed space 37.

  After the panel member 30 has three stages (step ST13: Yes), concrete is placed in the closed space 37 inside the panel member 30 (step ST14). If the five lifts necessary for the construction of the column main body 8 have not been completed (step ST15: No), the process returns to step ST11. If it is a predetermined lift that requires assembly of the main reinforcing bar 31 in step ST11 (Yes), the main reinforcing bar 31 is assembled (step ST16), and the operations after step ST12 are continued. When 5 lifts necessary for the construction of the column main body 8 are completed in step ST15 (Yes), the column main body in an unfinished state of the column main body 8 with the gap 41 extended upward as shown in FIG. Intermediate 48 is constructed and the process is completed.

  Returning to FIG. 9, after the pillar body intermediate construction work in step ST2, a pillar head construction work is performed (step ST3). FIG. 12 is a flowchart showing the procedure of the pillar head construction work shown in FIG. 9. As shown in FIG. 12, in the pillar head construction work, the panel members 30 for one step are arranged at predetermined positions on the pillar main body intermediate 48 (step ST21). If the number of steps of one lift (in this embodiment, three steps) is not reached (step ST22: No), the work of step ST21 is repeated, and after the number of steps of one lift is reached (step ST22: Yes), the hollow space is removed. The bottom formwork of the column head 9 to be closed is assembled (step ST23). Thereafter, the band reinforcing bars 32 of the panel members 30 adjacent to each other are coupled to each other (step ST24), and various reinforcing bars including the connecting main reinforcing bars 31D are assembled (step ST25). Further, the side mold 50 (see FIG. 13) is assembled so as to close the gap 41 (step ST26), concrete is placed (step ST27), and the column head 9 is constructed as shown in FIG. After the concrete is hardened, the support 4 (FIG. 2) is attached on the column head 9 (step ST28), and this process ends.

  When the pillar body intermediate construction work is completed, the superstructure of the bridge 1 for erection of the bridge girder 3 on the pillar head 9 can be started. Subsequent construction may be performed in parallel with the superstructure.

  Returning to FIG. 9, the description will be continued. After the column head construction work in step ST3, a gap lower space filling work is performed (step ST4). FIG. 14 is a flowchart showing a procedure of the gap lowering work shown in FIG. As shown in FIG. 14, in the gap lower space filling work, the band reinforcing bars 32 of the panel members 30 adjacent to each other are connected to each other by the band reinforcing bar joint unit 43 in a space lower than the lower cut beam 22 (step ST31), the side mold frame 50 (see FIG. 15) is assembled so as to close the space between the inner panels 35 and the outer panels 34 of the panel member 30 disposed on both sides of the gap 41 (step ST32). Thereafter, concrete is placed in the gap 41 closed by the side mold 50 to fill the lower portion of the gap 41 (step ST33), and this process is completed. The concrete of the gap lower stuffing work corresponds to the first lift in the gap 41.

  FIG. 15 is a front view of the pier 2 in a state in which the gap lowering work has been completed. Returning to FIG. 9, the description will be continued. After step ST4, the gap lower portion is filled, and water is poured into the steel sheet pile well 16 to a height lower than the upper end of the lower portion of the gap 41 as shown in FIG. 15 (step ST5), and the support work 20 is removed. (Step ST6). Thereafter, the gap upper portion is stuffed (step ST7).

  FIG. 16 is a flowchart showing the procedure of the gap upper space shown in FIG. As shown in FIG. 16, in the gap upper stuffing process, the next lift is a predetermined lift that requires assembly of the main reinforcing bars 31 (in this embodiment, the second and fourth lifts) (steps). (ST41: Yes), the main rebar 31 for the second and third lifts is assembled in the space where the cut beam 22 in the gap 41 is removed (step ST42). Next, the band reinforcing bars 32 of the panel members 30 adjacent to each other are connected to each other by the band reinforcing bar joint unit 43 (step ST43), the side mold frame 50 of the second lift is assembled (step ST44), and is closed by the side mold frame 50. Concrete is placed in the formed gap 41 (step ST45). Since the second to fifth 4 lifts are not completed (step ST46: No), the steps after step ST41 are repeated. In step ST41, when it is the fourth lift (Yes), when assembling the main reinforcing bar 31 in step ST42, the main reinforcing bar 31 is also connected to the lower end of the connecting main reinforcing bar 31D disposed above. The fifth lift of concrete is placed by reverse winding (step ST45), and when the four lifts are completed (step ST46: Yes), this process ends.

  FIG. 17 is a front view of the pier 2 in a state in which the gap upper stuffing work has been completed. Returning to FIG. 9, the description will be continued. After the gap upper portion filling work in step ST7, a backfill material such as earth and sand is backfilled in the steel pipe sheet pile well 16 (step ST8), the steel pipe sheet pile 11 is cut, and the upper part is removed (step ST9). Thereby, the pier 2 shown in FIG.1 and FIG.2 is completed.

  Next, the feature point of the bridge pier construction method of this embodiment which builds the bridge pier 2 in such a procedure, and the effect are demonstrated.

  As shown in FIGS. 10 and 11, in the present pier construction method, step ST12 in which a plurality of panel members 30 are arranged along the outline of the column main body portion 8 with a gap 41 at least in one circumferential direction. Step ST14 in which concrete is placed in a closed space 37 other than the portion provided with the gap 41, which is closed by the outer panel 34, the inner panel 35, and the at least two connecting panels 36, and the height of the column body 8 (Step ST15 becomes Yes), and the column main body intermediate 48 which is the unfinished state of the column main body 8 with the gap 41 extended upward is constructed (Step ST2). Subsequently, as shown in FIGS. 9 and 13, a pillar head construction work for constructing the pillar head 9 is performed on the pillar main body intermediate 48 (step ST3), and thereafter, as shown in FIGS. 15 and 17. Further, the column main body portion 8 is completed by filling the gap 41 of the column main body intermediate body 48 below the column head 9 (step ST4 and step ST7).

  Therefore, the superstructure of the bridge 1 performed on the pillar head 9 can be started after the pillar head construction work in step ST3 and before the pier construction is completed. More specifically, four, two stages, a total of eight cut beams 22 are provided so as to pass through the space for constructing the pier 2 as shown in FIGS. 3 and 4. Therefore, conventionally, the lower part of the pier 2 is constructed to a height lower than the lower beam 22 and water is poured into the steel pipe sheet pile well 16 to a height lower than the upper end of the constructed bridge pier 2, or After removing the supporting work 20 by backfilling, the pier 2 was constructed by the procedure of resuming the construction of the pier 2. Therefore, the superstructure could only be started after the column head 9 was completed and the pier construction was completed. On the other hand, in the pier construction method of the present embodiment, a pillar head construction work for constructing the pillar head 9 is performed before the pillar body portion 8 is completed (step ST3), and the steps after step ST4 for completing the pillar body portion 8 are performed. Since the construction is not critical and can be performed in parallel with the superstructure, the bridge construction period can be shortened.

  In the gap lower gap filling step (step ST4) and the gap upper gap filling step (step ST7) for completing the column main body portion 8, as shown in FIGS. The band reinforcing bars 32 of the arranged panel member 30 are connected to each other via the band reinforcing bar joint unit 43 (step ST31, step ST43), and between the inner panel 35 and the outer side of the panel member 30 arranged on both sides of the gap 41. The side molds 50 are assembled so as to close the space between the panels 34 (step ST32, step ST44), and concrete is placed in the gap 41 closed by the side molds 50 (step ST33, step ST45). Therefore, even if the column head portion 9 is constructed in step ST3 before step ST7 for completing the column main body portion 8, the column main body portion 8 can be completed after the belt reinforcing bars 32 are continued in the circumferential direction.

  In the pillar head construction work (step ST3) for constructing the pillar head 9, as shown in FIGS. 12 and 13, the connecting main reinforcing bars 31D extending downward from the pillar head 9 and arranged in the gap 41 are assembled ( Step ST25). Further, in the gap upper gap work (step ST7) for completing the column main body 8, the main reinforcing bar 31 is extended and connected to the connecting main reinforcing bar 31D as shown in FIG. 16 (step ST42). Therefore, even if the column head portion 9 is constructed in step ST3 before step ST7 for completing the column main body portion 8, the column main body portion 8 can be completed after the main reinforcing bars 31 are continued in the vertical direction.

  In the gap lower gap filling step (step ST4), as shown in FIG. 14, the side formwork 50 is assembled in a space lower than the cut beam 22 (step ST32), and concrete is placed in the gap 41 (step ST33). ). In addition, as shown in FIG. 9, after the pillar head construction work (step ST3) for constructing the pillar head 9, the cutting beam 22 is removed (step ST6), and the gap upper spacing work (step ST7), As shown in FIG. 16, in the space from which the cut beam 22 has been removed, the side formwork 50 is assembled (step ST44), and concrete is placed in the gap 41 (step ST45) to complete the column main body portion 8. . By adopting such a procedure, it becomes possible to construct the column head 9 on the column main body intermediate 48 constructed with the beam 22 remaining, and step ST6 for removing the beam 22 is critical. Not. This makes it possible to shorten the construction period for bridge construction. Moreover, the pillar main body 8 can be completed by removing the gaps 22 in stages while removing the beam 22.

  As shown in FIG. 9, the gap lower portion filling step (step ST4) for filling the lower portion of the gap 41 does not interfere with the beam 22, so that the column head constructing step (step ST3) for constructing the column head 9. For example, the column main body intermediate construction work (step ST2) for constructing the column main body intermediate 48 may be performed together. However, in doing so, it takes more time to build the column body intermediate 48. In the present embodiment, the gap lowering work (step ST4) is performed after the column head construction work (step ST3). Therefore, it is possible to quickly construct the column main body intermediate 48 and perform the column head construction work (step ST3) earlier.

  In addition, before removing the lower beam 22 in step ST6, water is injected around the pier 2 below the lower beam 22 (step ST5), and the gap lower space is filled (step ST4). Later, earth and sand are backfilled around the pier 2 (step ST8). Thus, since the water injection and backfilling into the steel pipe sheet pile canteen 16 around the pier 2 are performed in stages, the cut beam 22 can be safely removed in step ST6.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, in the above-described embodiment, the side mold frame 50 is assembled in order to close the gap 41 in step ST32 and step ST44, but the joint panel 40 made of concrete forming the periphery of the pier 2 may be assembled. In addition, the gap lower gap filling process in step ST3 may be performed before the column head construction work in step ST3. Alternatively, below the beam 22, the circumferential length of the panel member 30 is increased so as not to form the gap 41, and the concrete panel is formed by the joint panel 40 in the same manner as between the panel members 30 adjacent to each other in the bridge axis direction. You may make it close | close. Furthermore, in the said embodiment, in the pillar head construction work, although the panel member 30 is arranged (step ST21), you may assemble a formwork without using the panel member 30. FIG. In the above-described embodiment, the cross-sectional shape of the pier 2 is an oval substantially constant shape, but it may be a rectangle or a circle, and may vary depending on the position in the vertical direction. In addition, the specific configuration, arrangement, quantity, and procedure of each member and part can be changed as long as they do not depart from the spirit of the present invention. On the other hand, not all the constituent elements shown in the above embodiment are necessarily essential, and can be appropriately selected.

1 Bridge 2 Pier 3 Bridge Girder 8 Column body 9 Column head 10 Foundation (Steel pipe sheet pile well)
DESCRIPTION OF SYMBOLS 20 Supporting work 22 Cutting beam 30 Panel member 30A Corner panel member 30B Intermediate panel member 31 Main reinforcing bar 31D Main reinforcing bar for connection 32 Reinforcing bar 33 Intermediate reinforcing bar 34 Outer panel 35 Inner panel 36 Connection panel 37 Closed space 38 Reinforcing bar 41 Clearance 43 Band rebar joint unit (mechanical joint unit)
48 Column body intermediate 50 Side formwork

Claims (6)

A construction method of an pier having a column main body and a column head arranged on the column main body,
A plurality of panels made of precast concrete having an outer panel, an inner panel, and a connecting portion that connects the outer panel and the inner panel, and a plurality of reinforcing bars including a plurality of reinforcing bars and intermediate reinforcing bars Preparing a member;
Arranging the plurality of panel members along the outline of the column main body part and at least at one circumferential position;
Placing concrete in a closed space other than the portion provided with the gap, which is closed by the outer panel, the inner panel and at least two of the connecting portions;
The step of arranging the panel members and the step of placing concrete in the closed space are repeated until the height of the column main body is reached, and the gap is extended upward, and the column main body is in an incomplete state. Building a pillar body intermediate;
Building the column head on the column body intermediate;
Filling the gap of the column main body intermediate below the column head to complete the column main body portion. The step of completing the pillar main body is as follows:
Connecting the reinforcing bars of the panel members arranged on both sides of the gap to each other via a mechanical joint unit;
Assembling a joint panel made of precast concrete that forms the periphery of the formwork or the column main body so as to close the space between the inner panels and the outer panels of the panel members disposed on both sides of the gap;
2. The pier construction method according to claim 1, further comprising: placing concrete in the gap closed by the formwork or the joint panel. The step of constructing the column head includes a step of assembling a connecting main rebar extending downward from the column head and arranged in the gap,
The pier construction method according to claim 2, wherein the step of completing the column main body further includes a step of extending a main reinforcing bar and connecting the main reinforcing bar to the connecting main reinforcing bar. At least one cutting beam is provided in a portion where the column main body portion is constructed, and the gap is provided in two circumferential directions passing through the column main body portion in plan view with respect to each cutting beam. And
After the step of constructing the column head, further comprising the step of removing the at least one beam;
The step of completing the pillar main body is as follows:
In the space lower than the at least one beam, the step of assembling the formwork or the joint panel and the step of placing concrete in the gap to fill the lower portion of the gap;
Including a step of assembling the formwork or the joint panel and a step of placing concrete in the gap in the space where the at least one beam is removed, and filling the upper portion of the gap. The pier construction method according to claim 2 or claim 3, wherein   The pier construction method according to claim 4, wherein the step of filling the lower portion of the gap is performed after the step of constructing the column head. The pier is built on a steel pipe sheet pile well foundation,
Before the step of removing the beam, a first backfilling step of backfilling or pouring water around the pier below the beam;
6. The pier construction according to claim 4, further comprising a second backfilling step of backfilling or pouring water around the pier after the step of filling the lower portion of the gap. Method.

Images