Concrete slab, manufacturing method of concrete slab, and bonding method of concrete slab

Abstract

To provide a concrete slab, a manufacturing method of the concrete slab, and a bonding method of the concrete slab that can restrain creep deformation in a concrete slab with inclination on an upper surface.SOLUTION: A concrete slab 1 according to one embodiment comprises: a concrete block 5 extending in a first direction D1, a second direction D2, and a third direction D3, and having an upper surface 2 extending obliquely upward as approaching the center of the first direction D1; and a sheath pipe 6 provided within the interior of the concrete block 5 with a post-tension steel material 7 inserted therein. The sheath pipe 6 extends obliquely upward as approaching the center of the first direction D1 so as to be along the upper surface 2.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a concrete slab, a method for manufacturing a concrete slab, and a method for joining a concrete slab. [Background technology]

[0002] Patent Document 1 describes a concrete deck construction method for repairing a concrete deck of a bridge. This construction method includes a first concrete deck installation step, a first prestressing step, a second concrete deck installation step, a removal step, an insertion step, and a second prestressing step.

[0003] In the first concrete slab installation process, the existing concrete slab is removed, and then two or more divided first concrete slabs are newly installed. In the first prestressing process, first post-tensioning members are inserted into the multiple first concrete slabs, and prestress is applied to the multiple first concrete slabs by the first post-tensioning members.

[0004] In the second concrete slab installation process, the second concrete slab is installed adjacent to the first concrete slab, and in the removal process, the first post-tensioning member is removed from the first concrete slab. In the insertion process, the second post-tensioning member is inserted into the first concrete slab and the second concrete slab from which the first post-tensioning member has been removed.

[0005] In the second prestressing process, prestress is applied to the first and second concrete slabs using second post-tensioning members. This construction method allows prestressing without connecting the post-tensioning members, improving the flexibility of the concrete slabs during construction. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6808585 Summary of the Invention [Problem to be solved by the invention]

[0007] Concrete slabs are sometimes used with a sloped top surface for drainage and other purposes. This type of concrete slab has a top surface that extends diagonally upward or downward toward the center. However, pretensioning may be applied to this type of concrete slab in a direction different from the direction in which the top surface extends. In this case, prestress is applied in a direction different from the top surface, which can cause eccentricity of the prestress. When prestressing becomes eccentric, elastic deformation or creep deformation may occur in the concrete slab.

[0008] The present disclosure aims to provide a concrete slab that can suppress creep deformation in a concrete slab having a slope on the upper surface, a method for manufacturing a concrete slab, and a method for joining a concrete slab. [Means for solving the problem]

[0009] The concrete slab according to the present disclosure is (1) a concrete slab that extends in a first direction and a second direction intersecting the first direction and has a thickness in a third direction intersecting both the first and second directions. The concrete slab includes a concrete block that extends in the first, second, and third directions and has an upper surface that extends diagonally upward or downward toward the center in the first direction, and a sheath pipe provided inside the concrete block and through which post-tensioning steel is inserted. The sheath pipe extends diagonally upward or downward toward the center in the first direction along the upper surface.

[0010] This concrete slab comprises concrete blocks extending in a first direction, a second direction, and a third direction, each having an upper surface that extends diagonally upward or downward toward the center in the first direction. The concrete slab comprises sheath pipes, through which post-tensioning steel is inserted. The sheath pipes extend diagonally upward or downward toward the center in the first direction, along the upper surface of the concrete block. Therefore, even if pretension is introduced in a direction different from the direction in which the upper surface extends, eccentricity of the prestress can be suppressed by inserting post-tensioning steel into the sheath pipes along the upper surface to introduce post-tension into the concrete slab. Therefore, by introducing prestress using post-tensioning steel inserted into the sheath pipes extending along the upper surface of the concrete block, elastic deformation and creep deformation of the concrete slab can be suppressed.

[0011] (2) In the above (1), the concrete slab may include pretensioning steel extending along the first direction inside the concrete block. In this case, prestress is introduced inside the concrete block by the pretensioning steel extending along the first direction. Even in this case, prestress is introduced by posttensioning steel inserted into a sheath pipe extending diagonally upward or downward along the top surface toward the center in the first direction, thereby suppressing eccentricity of the prestress and creep deformation.

[0012] The method for manufacturing a concrete slab according to the present disclosure is (3) a method for manufacturing a concrete slab that extends in a first direction and a second direction intersecting the first direction and has a thickness in a third direction intersecting both the first and second directions. The method for manufacturing a concrete slab includes the steps of arranging pretensioning steel along the first direction and tensioning the pretensioning steel, arranging a sheath tube that extends diagonally upward or diagonally downward toward the center in the first direction and through which a post-tensioning steel is inserted, and pouring concrete into the pretensioning steel and the sheath tube to manufacture a concrete block having an upper surface that extends diagonally upward or diagonally downward toward the center in the first direction along the sheath tube.

[0013] In this method of manufacturing a concrete slab, pretensioning steel is placed along a first direction and tensioned. A sheath tube is placed, extending diagonally upward or downward toward the center in the first direction. Concrete is then poured into the tensioned pretensioning steel and sheath tube, producing a concrete block with an upper surface that extends diagonally upward or downward toward the center in the first direction along the sheath tube. Therefore, by inserting post-tensioning steel into the sheath tube to introduce post-tension into the concrete slab, it is possible to suppress eccentricity of prestress, as with the concrete slab described above, and therefore suppress elastic deformation and creep deformation in the concrete slab.

[0014] The concrete slab joining method according to the present disclosure is (4) a concrete slab joining method for joining multiple precast slabs to the aforementioned concrete slab. The multiple precast slabs include a center precast slab having a first continuous surface continuous with its upper surface and a first sheath pipe therein, and end precast slabs having a second continuous surface continuous with the first continuous surface and a second sheath pipe therein. The concrete slab joining method includes the steps of inserting post-tensioning steel into the sheath pipe of the concrete slab to introduce prestress into the concrete slab with the post-tensioning steel, inserting post-tensioning tendons into the first and second sheath pipes, connecting the post-tensioning tendons extending from the first sheath pipe to the post-tensioning steel with connecting members, and tensioning the post-tensioning tendons extending from the second sheath pipe.

[0015] In this concrete slab joining method, a center-side precast slab and an end-side precast slab are joined to the concrete slab. The concrete slab is the concrete slab described above, and has an upper surface and sheath tubes that extend diagonally upward or downward toward the center in the first direction. Therefore, by inserting post-tensioning steel into the sheath tubes and introducing prestress into the concrete slab using the post-tensioning steel, it is possible to suppress prestress eccentricity and the occurrence of elastic deformation and creep deformation, as with the concrete slab described above. Furthermore, post-tensioning tendons inserted into the first sheath tube of the center-side precast slab and the second sheath tube of the end-side precast slab are connected to the post-tensioning steel of the concrete slab, and the post-tensioning tendons extending from the end-side precast slab are tensioned. This joining method allows the center-side precast slab and the end-side precast slab to be joined to the concrete slab, and tension can be applied to the center-side precast slab and the end-side precast slab.

[0016] (5) In the above (4), the method for joining concrete slabs may include the steps of erecting the concrete slab before connecting it to the post-tensioning steel, erecting end-side precast slabs after erecting the concrete slab, and erecting a center-side precast slab after erecting the end-side precast slab. In this case, the concrete slab, end-side precast slab, and center-side precast slab can be erected in this order. [Effects of the Invention]

[0017] According to the present disclosure, elastic deformation and creep deformation can be suppressed in a concrete slab having a slope on the upper surface. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 10 is a cross-sectional view showing an example of a completed deck slab connection structure in which the upper and lower lines are integrated. [Figure 2] FIG. 1 is a plan view showing a concrete floor slab according to an embodiment. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] FIG. 3 is a cross-sectional view taken along line BB in FIG. 2. [Figure 5] 1( a ), 1 ( b ), and 1 ( c ) are diagrams showing steps of a concrete floor slab joining method according to an embodiment. [Figure 6] 1( a ), 1 ( b ), and 1 ( c ) are diagrams showing steps of a concrete floor slab joining method according to an embodiment. [Figure 7] 1( a ), 1 ( b ), and 1 ( c ) are diagrams showing steps of a concrete floor slab joining method according to an embodiment. [Figure 8] FIG. 10 is a cross-sectional view showing an example of a connecting member. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of a concrete slab, a manufacturing method for a concrete slab, and a joining method for a concrete slab according to the present disclosure will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements are given the same reference numerals, and duplicate explanations will be omitted as appropriate. The drawings may be partially simplified or exaggerated for ease of understanding, and dimensional ratios, angles, etc. are not limited to those described in the drawings.

[0020] Fig. 1 is a diagram showing a cross section of an example viaduct B equipped with a concrete slab 1 according to this embodiment. As shown in Fig. 1, the viaduct B has, for example, a concrete slab 1 extending in a first direction D1 and a second direction D2 intersecting the first direction D1 and having a thickness in a third direction D3 intersecting both the first direction D1 and the second direction D2, and a plurality of precast slabs 10 joined to the concrete slab 1.

[0021] For example, the first direction D1 is the width direction (direction perpendicular to the bridge axis), the second direction D2 is the bridge axis direction, and the third direction D3 is the vertical direction. Also, the first direction D1 is the longitudinal direction of the concrete slab 1, the second direction D2 is the lateral direction (width direction) of the concrete slab 1, and the third direction D3 is the thickness direction of the concrete slab 1.

[0022] The viaduct B has wall parapets B1 constructed on precast slabs 10 located at both ends in the first direction D1. The multiple precast slabs 10 include a central precast slab 20 joined to the concrete slab 1, and end precast slabs 30 joined to the central precast slab 20 on the side opposite to the concrete slab 1.

[0023] For example, the concrete slab 1 is located in the center of the viaduct B in the first direction D1, and the end-side precast slab 30 is located at the end of the viaduct B in the first direction D1. The center-side precast slab 20 is located between the concrete slab 1 and the end-side precast slab 30. The concrete slab 1 has an upper surface 2 that extends diagonally upward toward the center in the first direction D1. In other words, the concrete slab 1 has a convex upper surface 2. The center-side precast slab 20 has a first continuous surface 21 that is continuous with the upper surface 2, and the end-side precast slab 30 has a second continuous surface 31 that is continuous with the first continuous surface 21.

[0024] The concrete slab 1 has, for example, a lower surface 3 whose height corresponds to the linear arrangement of the pretensioning steel 8. The central precast slab 20 has a first lower surface 22 that is continuous with the lower surface 3, and the end-side precast slab 30 has a second lower surface 32 that is continuous with the first lower surface 22. For example, in the concrete slab 1, the lower surface 3 extends parallel to the upper surface 2. For example, in the central precast slab 20, the first lower surface 22 extends parallel to the first continuous surface 21, and in the end-side precast slab 30, the second lower surface 32 extends parallel to the second continuous surface 31.

[0025] The concrete deck 1 has a haunch portion 4 that protrudes downward on its underside 3. The central precast deck 20 has a haunch portion 23 that protrudes downward on its first underside 22, and the end-side precast deck 30 has a haunch portion 33 that protrudes downward on its second underside 32. For example, the haunch portions 4, 23, and 33 are trapezoidal. The central precast deck 20 has a first sheath pipe 24 through which a post-tensioning tendon 40 (described below) is inserted, and the end-side precast deck 30 has a second sheath pipe 34 through which the post-tensioning tendon 40 is inserted. Note that the first sheath pipe 24, second sheath pipe 34, and post-tensioning tendon 40 are shown in simplified form in the drawings.

[0026] The viaduct B has multiple steel girders B2 arranged along the first direction D1. Note that the steel girders B2 are simplified in the drawings. The concrete deck 1 is erected with its haunch portion 4 resting on the steel girders B2. Similarly, the center precast deck 20 is erected with its haunch portion 23 resting on the steel girders B2, and the end precast deck 30 is erected with its haunch portion 33 resting on the steel girders B2.

[0027] Fig. 2 is a plan view showing the concrete slab 1. As shown in Fig. 1 and Fig. 2, the concrete slab 1 has concrete blocks 5 extending in a first direction D1, a second direction D2, and a third direction D3, sheath pipes 6 provided inside the concrete blocks 5, post-tensioning steel members 7 inserted into the sheath pipes 6, and pre-tensioning steel members 8.

[0028] The concrete block 5 indicates the concrete portion other than the sheath pipe 6, the post-tensioning steel material 7, and the pre-tensioning steel material 8. The concrete block 5 is made of concrete. For example, the concrete block 5 may be made of high-strength fiber-reinforced concrete. The concrete block 5 may also be made of UHPFRC (Ultra High Performance Fiber Reinforced cement-based Composites). In this case, the concrete block 5 can be made high in strength.

[0029] The concrete block 5 has an end face 5c at the end in the first direction D1 that extends in the second direction D2 and the third direction D3. The end face 5c is the surface facing the precast floor slab 10 (central precast floor slab 20). The concrete block 5 has a pair of end faces 5c, and the pair of end faces 5c are aligned along the first direction D1.

[0030] The concrete block 5 has a plurality of through holes 5b. The through holes 5b are holes that penetrate the concrete deck 1 in the third direction D3. As an example, the through holes 5b have an oval shape extending in the first direction D1 when viewed along the third direction D3. In the concrete block 5, a plurality of through holes 5b are lined up along the first direction D1, and a plurality of through holes 5b are lined up along the second direction D2. Studs fixed to the steel girders B2 are inserted into the through holes 5b.

[0031] Figure 3 is a schematic diagram of a cross section taken along line AA in Figure 2. Figure 4 is a schematic diagram of a cross section taken along line BB in Figure 2. As shown in Figures 2, 3, and 4, the concrete slab 1 has a plurality of post-tensioning steel members 7 and a plurality of pre-tensioning steel members 8. The post-tensioning steel members 7 extend inside and along the sheath tube 6. The pre-tensioning steel members 8 extend linearly, for example, along the first direction D1.

[0032] For example, the pretensioning steel 8 is made of PC steel. The multiple pretensioning steels 8 are arranged, for example, at positions symmetrical with respect to the reference line X. The reference line X passes through the center of the concrete slab 1 in a plan view (when viewed along the third direction D3) and extends along the first direction D1. For example, the pretensioning steels 8 are arranged at both ends and the center in the second direction D2 in a plan view when viewed from the sheath tube 6.

[0033] For example, the multiple pretensioning steel members 8 include upper pretensioning steel members 8b located on the upper surface 2 side of the concrete slab 1 and lower pretensioning steel members 8c located on the lower surface 3 side of the concrete slab 1. The upper pretensioning steel members 8b and the lower pretensioning steel members 8c are aligned inside the concrete block 5 along the third direction D3.

[0034] For example, upper pretensioning steel members 8b and lower pretensioning steel members 8c are arranged at both ends and the center in the second direction D2 in a plan view from the sheath tube 6. For example, a plurality of upper pretensioning steel members 8b and a plurality of lower pretensioning steel members 8c are arranged between a pair of sheath tubes 6 lined up along the second direction D2. In the above, an example has been described in which pretensioning steel members are arranged in two rows, one above the other, such as the upper pretensioning steel members 8b and the lower pretensioning steel members 8c. However, the pretensioning steel members may be arranged in a single row.

[0035] At both ends in the second direction D2 in plan view, the lower pretensioning steel material 8c, the upper pretensioning steel material 8b, and the sheath tube 6 are arranged in this order. Between the pair of sheath tubes 6, the lower pretensioning steel material 8c, the upper pretensioning steel material 8b, the upper pretensioning steel material 8b, and the lower pretensioning steel material 8c are arranged in this order.

[0036] For example, the number of sheath tubes 6 provided inside the concrete slab 1 is less than the number of pretensioning steel members 8 provided inside the concrete slab 1. For example, the concrete slab 1 has eight pretensioning steel members 8 and two sheath tubes 6. For example, the two sheath tubes 6 are arranged in positions symmetrical to each other with respect to the reference line X.

[0037] The concrete slab 1 includes a plurality of reinforcing bars 9 embedded in a concrete block 5. For example, the plurality of reinforcing bars 9 include a plurality of first reinforcing bars 9b extending in a first direction D1, a plurality of second reinforcing bars 9c extending in a second direction D2, a first haunch reinforcing bar 9d extending in the haunch portion 4 along the first direction D1, and a second haunch reinforcing bar 9f extending in the haunch portion 4 along the second direction D2.

[0038] For example, two first reinforcing bars 9b are lined up along the third direction D3, and two second reinforcing bars 9c are lined up along the third direction D3. For example, the concrete slab 1 has a plurality of haunch portions 4. For example, the plurality of haunch portions 4 include a first haunch portion 4A located in the center of the concrete slab 1 in the first direction D1, and a pair of second haunch portions 4B located at each end of the concrete slab 1 in the first direction D1.

[0039] The first haunch portion 4A has a pair of inclined surfaces 4b aligned along the first direction D1 and a lower surface 4c located between the pair of inclined surfaces 4b. The second haunch portion 4B has a lower surface 4c located at an end of the concrete slab 1 in the first direction D1 and a lower inclined surface 4b extending obliquely upward from an end opposite to the end surface 5c of the lower surface 4c.

[0040] For example, haunch portions 4 are formed at both ends and the center in the first direction D1 of the concrete floor slab 1. The first haunch reinforcement 9d has an inclined portion 9g that extends along the inclined surface 4b of the haunch portion 4, and an extended portion 9h that extends along the underside 4c of the haunch portion 4. A plurality of first haunch reinforcement 9d and a plurality of second haunch reinforcement 9f are arranged in each haunch portion 4. Note that if the height of the concrete floor slab 1 is low, the arrangement of the first haunch reinforcement 9d and second haunch reinforcement 9f may be omitted.

[0041] As described above, the upper surface 2 of the concrete slab 1 extends obliquely upward toward the center in the first direction D1. For example, the upper surface 2 has a top 2b located in the center of the first direction D1, a first inclined surface 2c extending from the top 2b to one end surface 5c, and a second inclined surface 2d extending from the top 2b to the other end surface 5c. For example, the first inclined surface 2c and the second inclined surface 2d are flat surfaces. For example, the gradient of the first inclined surface 2c with respect to the first direction D1 and the gradient of the second inclined surface 2d with respect to the first direction D1 are 2%. However, these gradients are not limited to 2% and can be changed as appropriate.

[0042] The sheath tube 6 extends along the upper surface 2. That is, the sheath tube 6 is inclined toward the same side as the upper surface 2. In this embodiment, the upper surface 2 and the sheath tube 6 have a mountain-like shape that extends obliquely upward toward the center in the first direction D1. Like the upper surface 2, the sheath tube 6 extends obliquely upward toward the center in the first direction D1.

[0043] For example, the sheath tube 6 has a curved portion 6b located in the center in the first direction D1, a first inclined portion 6c extending from the curved portion 6b to one end face 5c, and a second inclined portion 6d extending from the curved portion 6b to the other end face 5c. For example, the first inclined portion 6c and the second inclined portion 6d extend linearly.

[0044] For example, the gradient of the first inclined portion 6c with respect to the first direction D1 may be the same as the gradient of the first inclined surface 2c with respect to the first direction D1, or may be different from the gradient of the first inclined surface 2c with respect to the first direction D1. Similarly, the gradient of the second inclined portion 6d with respect to the first direction D1 may be the same as the gradient of the second inclined surface 2d with respect to the first direction D1, or may be different from the gradient of the second inclined surface 2d with respect to the first direction D1. As an example, the gradient of the first inclined portion 6c with respect to the first direction D1 and the gradient of the second inclined portion 6d with respect to the first direction D1 are 2%. However, these gradients are not limited to 2% and can be changed as appropriate.

[0045] For example, the curved portion 6b is curved so as to protrude upward toward the center in the first direction D1. As an example, the curved portion 6b has an arc shape. The curved portion 6b is located between the first inclined portion 6c and the second inclined portion 6d. By positioning the curved portion 6b at the center of the sheath tube 6 in the first direction D1, it is possible to prevent the post-tensioning steel material 7 inserted into the sheath tube 6 from breaking at the center of the sheath tube 6 in the first direction D1.

[0046] Next, an example of a manufacturing method for the concrete deck 1 will be described. First, a formwork is prepared. The formwork is shaped so that, when concrete is poured, an upper surface 2 and a lower surface 3 that extend diagonally upward toward the center in the first direction D1, as well as a haunch portion 4 and an end surface 5c, are formed. A sheath pipe 6, pretensioning steel material 8, and reinforcing bars 9 are placed inside this formwork.

[0047] The pretensioning steel materials 8 are arranged along the first direction D1, and the pretensioning steel materials 8 are placed in a tensioned state (a step of tensioning the pretensioning steel materials). More specifically, a plurality of upper pretensioning steel materials 8b and a plurality of lower pretensioning steel materials 8c are arranged, and the plurality of upper pretensioning steel materials 8b and the plurality of lower pretensioning steel materials 8c are placed in a tensioned state. The sheath tube 6 is arranged inside the formwork so as to extend obliquely upward toward the center in the first direction D1 (a step of placing the sheath tube). Then, the first reinforcing bars 9b, the second reinforcing bars 9c, the first haunch bars 9d, and the second haunch bars 9f are arranged inside the formwork.

[0048] Thereafter, concrete is filled into the formwork, and the concrete is poured onto the pretensioning steel 8 and sheath tube 6 to produce a concrete block 5 (a process for producing a concrete block). More specifically, concrete is poured into the formwork in which the sheath tube 6, the plurality of pretensioning steels 8, and the plurality of reinforcing bars 9 are arranged, and the concrete is allowed to harden, thereby producing the concrete block 5. After the concrete has hardened, primary prestress is introduced by releasing both ends of the pretensioning steel 8. A concrete block 5 is then produced, having an upper surface 2 and a lower surface 3 that extend obliquely upward along the sheath tube 6 toward the center in the first direction D1.

[0049] Then, post-tensioning steel material 7 is inserted into the sheath pipe 6 of the concrete block 5. At this time, the post-tensioning steel material 7 extends diagonally upward toward the center in the first direction D1 along the sheath pipe 6. The post-tensioning steel material 7 inserted into the sheath pipe 6 introduces secondary prestress to the concrete block 5 by the post-tensioning method.

[0050] More specifically, one end of the post-tensioning steel 7 is fixed to a connecting member 50 (see FIG. 8) located on the end face 5c, and a reaction force is obtained from the concrete block 5 to pull the other end of the post-tensioning steel 7, thereby applying a compressive force to the concrete block 5 in the first direction D1. In other words, prestress is introduced by obtaining a reaction force from the concrete block 5 that pulls the post-tensioning steel 7. After this prestress is introduced, both ends of the post-tensioning steel 7 are fixed to the connecting member 50. Through the above steps, the manufacture of the concrete deck 1 is completed.

[0051] Next, a joining method for concrete deck slabs 1 according to this embodiment will be described. Below, an example of construction work will be described in which an existing deck C of a road L of a viaduct B having an up track L1 and an down track L2 is replaced with a concrete deck slab 1, a center precast deck 20, and an end precast deck 30, as shown in Fig. 5(a). The existing deck C is installed on steel girders B2. For simplification, the steel girders B2 are not shown in Figs. 5, 6, and 7.

[0052] This construction is carried out while maintaining multiple lanes through which vehicle V can pass. For example, the existing viaduct B has a first lane Z1, a second lane Z2, a third lane Z3, a fourth lane Z4, a fifth lane Z5, and a sixth lane Z6, in that order, through which vehicle V can pass. The first lane Z1, the second lane Z2, and the third lane Z3 are provided on the outbound lane L2, and the fourth lane Z4, the fifth lane Z5, and the sixth lane Z6 are provided on the inbound lane L1. The construction to update the deck C of the outbound lane L2 will be described below.

[0053] For example, in this construction, the up line L1 and down line L2 are integrated, and the down line L2 is widened by updating the deck slab. First, the wall parapet B1 and deck slab C located near the center of the viaduct B in the first direction D1 are removed. At this time, the wall parapet B1 and deck slab C of the up line L1 located near the center of the viaduct B in the first direction D1 are removed, and the wall parapet B1 and deck slab C of the down line L2 located near the center of the viaduct B in the first direction D1 are also removed to open up space S for installing the concrete deck slab 1.

[0054] As described above, prestress is introduced to the concrete slab 1 in advance using the post-tensioning steel material 7 (prestress introduction process). That is, the post-tensioning steel material 7 is inserted into the sheath pipe 6 of the concrete slab 1, and prestress is introduced to the concrete slab 1 by the post-tensioning steel material 7.

[0055] 5(b), the concrete slab 1 is erected (the process of erecting the concrete slab). Specifically, in the space S, the haunch portion 4 is placed on the steel girder B2, and reinforcing bars are placed between the slab C and each end of the concrete block 5 in the first direction D1, and filler material Y is poured, thereby erecting the concrete slab 1 in the center of the viaduct B in the first direction D1.

[0056] After the installation of the concrete slab 1 is completed, the lanes that vehicle V can travel through are switched as shown in Figures 5(b) and 5(c). Specifically, the first lane Z1, second lane Z2, and third lane Z3 are switched to the first new lane N1 located on the slab C adjacent to the concrete slab 1, and the second new lane N2 and third new lane N3 located on the concrete slab 1.

[0057] At this time, a movable guardrail P is installed on the end side of the first new lane N1 in the first direction D1. For example, the movable guardrail P can be moved in the first direction D1 by running a guardrail switching vehicle. As an example, the movable guardrail P is a road zipper system. By moving the movable guardrail P in the first direction D1, it is possible to increase the number of lanes on which vehicles V can travel during the day to multiple lanes, and to reduce the number of lanes on which vehicles V can travel at night to a single lane.

[0058] Then, the protective fence B3 installed on the slab C is removed, and the slab C and wall parapet B1 located at the end of the down line L2 in the first direction D1 are removed. Next, as shown in Figures 5(c) and 6(a), the end-side precast slab 30 is erected (process of erecting the end-side precast slab). Then, a movable protective fence P is placed at the boundary between the slab C and the concrete slab 1, which is located on the opposite side of the end-side precast slab 30 when viewed from the concrete slab 1.

[0059] For example, the length in the first direction D1 of the end-side precast deck 30 is longer than the length in the first direction D1 of the removed deck C. This widens the viaduct B (down line L2). When erecting the end-side precast deck 30, the haunch portion 33 is placed on the steel girder B2, and the wall parapet B1 is installed on the end-side precast deck 30.

[0060] As shown in Figure 6(b), the first new lane N1 is closed and the fixed protective fence Q is moved to a position closer to the concrete slab 1. A new fixed protective fence Q is placed on the end-side precast slab 30, and the fourth new lane N4 on the end-side precast slab 30 becomes a lane that vehicles V can travel on.

[0061] As shown in Figures 6(b) and 6(c), the slab C located between the end-side precast slab 30 and the concrete slab 1 is removed. Then, the central precast slab 20 is erected between the end-side precast slab 30 and the concrete slab 1 (process of erecting the central precast slab). When erecting the central precast slab 20, the haunch portion 23 is placed on the steel girder B2, and reinforcing bars are placed between the central precast slab 20 and the end-side precast slab 30, and filler material Y is poured. The central precast slab 20 is joined to the end-side precast slab 30 using the above procedure. At this point, the central precast slab 20 is not joined to the concrete slab 1 and is separated from the concrete slab 1.

[0062] Next, as shown in Figure 7(a), a fifth new lane N5 above the boundary between the central precast slab 20 and the end-side precast slab 30, and a sixth new lane N6 above the central precast slab 20, are made lanes that vehicles V can travel on. At this time, a movable protective fence P is placed above the end of the central precast slab 20 on the concrete slab 1 side. Then, the slab C located between the central precast slab 20 and the concrete slab 1 is removed.

[0063] As shown in Figure 7(b), a new slab 25 having a sheath pipe 26 is placed between the central precast slab 20 and the concrete slab 1, and the new slab 25 is erected on the steel girder B2. Then, post-tensioning tendons 40 are inserted through the sheath pipe 26 of the new slab 25, the first sheath pipe 24 of the central precast slab 20, and the second sheath pipe 34 of the end-side precast slab 30 (step of inserting post-tensioning tendons).

[0064] Then, the post-tensioning tendons 40 extending from the sheath pipes 26 are connected to the post-tensioning steel members 7 of the concrete deck 1 by the connecting members (the process of connecting to the post-tensioning steel members). Figure 8 is a cross-sectional view showing a connecting member 50, which is an example of the connecting member. As shown in Figure 8, the connecting member 50 has an anchor plate 51, a spacer 52, a coupler sheath 53, a primary grip 54, a coupler sleeve 55, a secondary grip 56, a holding plate 57, and a float 58.

[0065] For example, the anchor plate 51 is disposed inside a recess 5d recessed along the first direction D1 in the end face 5c of the concrete block 5. The anchor plate 51 has an insertion hole 51b through which the post-tensioning steel material 7 is inserted, and a spacer 52 is disposed between the inner surface defining the insertion hole 51b and the post-tensioning steel material 7.

[0066] The coupler sheath 53 and the coupler sleeve 55 are cylindrical. The coupler sheath 53 and the coupler sleeve 55 are arranged outside the concrete block 5, and the coupler sleeve 55 is housed inside the coupler sheath 53. The primary grip 54, the secondary grip 56, and the holding plate 57 are arranged inside the coupler sleeve 55.

[0067] The coupler sheath 53 has a cylindrical portion 53b facing away from the concrete block 5, and the post-tensioning tendon 40 is inserted into the cylindrical portion 53b. The primary grip 54 tightens the post-tensioning steel 7 inserted into the insertion hole 51b of the anchor plate 51, and the secondary grip 56 tightens the post-tensioning tendon 40 inserted into the cylindrical portion 53b. In this way, the connection member 50 tightens the post-tensioning steel 7 and the post-tensioning tendon 40, thereby connecting the post-tensioning steel 7 to the post-tensioning tendon 40.

[0068] 7(b) and 7(c), a connecting member 50 is connected to the portion of the post-tensioning tendon 40 that extends from the first sheath pipe 24 and is inserted into the sheath pipe 26 of the new deck slab 25 and extends from the sheath pipe 26. A post-tensioning steel member 7 is connected to the connecting member 50 to which the post-tensioning tendon 40 is connected, and filler material Y is poured between the concrete deck slab 1 and the new deck slab 25, and between the new deck slab 25 and the central precast deck slab 20.

[0069] After the filler Y between the concrete slab 1 and the new slab 25, and the filler Y between the new slab 25 and the central precast slab 20, have hardened, the post-tensioning tendons 40 extending from the second sheath pipe 34 are pulled (step of pulling the post-tensioning tendons). This applies a compressive force in the first direction D1 to the new slab 25, the central precast slab 20, and the end-side precast slab 30.

[0070] That is, prestress is introduced by obtaining the reaction force that pulls the post-tensioning tendons 40 from the new deck 25, the center precast deck 20, and the end precast deck 30. Through the above steps, the replacement of the deck on the down track L2 of the viaduct B is completed. After that, for example, the replacement of the deck on the up track L1 of the viaduct B is carried out using the same procedure as the replacement of the deck on the down track L2. After that, the series of steps in the joining method for concrete deck slabs 1 according to this embodiment is completed.

[0071] Next, we will explain the effects obtained from the concrete slab 1 according to this embodiment, the method for manufacturing the concrete slab 1, and the method for joining the concrete slab 1. As shown in Figures 3 and 4, in the method for manufacturing the concrete slab 1 according to this embodiment, the concrete slab 1 includes concrete blocks 5 extending in a first direction D1, a second direction D2, and a third direction D3, and the concrete blocks 5 have upper surfaces 2 that extend obliquely upward toward the center in the first direction D1.

[0072] The concrete slab 1 is equipped with a sheath pipe 6, through which a post-tensioning steel member 7 is inserted. The sheath pipe 6 extends diagonally upward toward the center of the first direction D1 along the top surface 2 of the concrete block 5. Therefore, even if pretension is introduced by the pretensioning steel member 8 in a direction different from the direction in which the top surface 2 extends, eccentricity of the prestress can be suppressed by introducing post-tension into the concrete slab 1 by inserting the post-tensioning steel member 7 into the sheath pipe 6 along the top surface 2. Therefore, by introducing prestress using the post-tensioning steel member 7 inserted into the sheath pipe 6 extending along the top surface 2 of the concrete block 5, creep deformation of the concrete slab 1 can be suppressed.

[0073] In this embodiment, the concrete slab 1 is provided with pretensioning steel members 8 that extend along the first direction D1 inside the concrete block 5. In this case, prestress is introduced inside the concrete block 5 by the pretensioning steel members 8 that extend along the first direction D1. Even in this case, prestress is introduced by the pretensioning steel members 8 that are inserted into the sheath tubes 6 that extend diagonally upward along the top surface 2 toward the center in the first direction D1, thereby making it possible to suppress eccentricity of the prestress and creep deformation.

[0074] In the joining method for concrete slabs 1 according to this embodiment, as shown in Figures 5 to 7, a center-side precast slab 20 and an end-side precast slab 30 are joined to the concrete slab 1. In this joining method, post-tensioning tendons 40 inserted into the first sheath tube 24 of the center-side precast slab 20 and the second sheath tube 34 of the end-side precast slab 30 are connected to the post-tensioning steel 7 of the concrete slab 1, and the post-tensioning tendons 40 extending from the end-side precast slab 30 are pulled. This joins the center-side precast slab 20 and the end-side precast slab 30 to the concrete slab 1, and tension can be applied to the center-side precast slab 20 and the end-side precast slab 30.

[0075] In this embodiment, the joining method for the concrete slab 1 includes the steps of erecting the concrete slab 1 before connecting it to the post-tensioning steel 7, erecting the end-side precast slabs 30 after erecting the concrete slab 1, and erecting the center-side precast slab 20 after erecting the end-side precast slab 30. Therefore, the concrete slab 1, the end-side precast slab 30, and the center-side precast slab 20 can be erected in this order.

[0076] The above describes embodiments of the concrete slab, concrete slab manufacturing method, and concrete slab joining method according to the present disclosure. However, the concrete slab, concrete slab manufacturing method, and concrete slab joining method according to the present disclosure are not limited to the contents of the above-described embodiments, and may be modified within the scope of the gist described in the claims. In other words, the shape, size, material, number, and arrangement of each part of the concrete slab, as well as the content and order of the steps of the concrete slab manufacturing method and concrete slab joining method, can be modified as appropriate within the scope of the above gist.

[0077] For example, in the above-described embodiment, a concrete slab 1 was described that includes a concrete block 5 having an upper surface 2 that extends diagonally upward toward the center in the first direction D1, and a sheath pipe 6 that extends along the upper surface 2. However, the concrete slab may also include a concrete block having an upper surface that extends diagonally downward toward the center in the first direction D1, and a sheath pipe that extends diagonally downward along the upper surface toward the center in the first direction D1.

[0078] In the above-described embodiment, a concrete slab 1 is described that includes pretensioning steel 8 that extends linearly along the first direction D1. However, the type of pretensioning steel that the concrete slab includes is not limited to the pretensioning steel 8 and can be changed as appropriate. Furthermore, the concrete slab may not include pretensioning steel.

[0079] In the above-described embodiment, a description has been given of the concrete deck 1 used in the replacement work of the deck C of the viaduct B. However, the concrete deck according to the present disclosure is not limited to the replacement work of the deck C of the viaduct B, but may also be used in the installation work of a new deck, and can be used in various construction works. [Explanation of symbols]

[0080] REFERENCE SIGNS LIST 1...concrete slab, 2...upper surface, 2b...top, 2c...first inclined surface, 2d...second inclined surface, 3...bottom surface, 4...haunch portion, 4A...first haunch portion, 4B...second haunch portion, 4b...inclined surface, 4c...bottom surface, 5...concrete block, 5b...through hole, 5c...end surface, 5d...recess, 6...sheath tube, 6b...curved portion, 6c...first inclined portion, 6d...second inclined portion, 7...post-tensioning steel, 8...pre-tensioning steel, 8b...upper pre-tensioning steel 1. Pre-tensioning steel, 8c...lower pre-tensioning steel, 9...reinforcing bar, 9b...first reinforcing bar, 9c...second reinforcing bar, 9d...first haunch bar, 9f...second haunch bar, 9g...inclined portion, 9h...extension portion, 10...precast slab, 20...central precast slab, 21...first continuous surface, 22...first lower surface, 23...haunch portion, 24...first sheath pipe, 25...newly constructed slab, 26...sheath pipe, 30...end precast slab, 31...second continuous surface, 32... Second underside, 33...haunch portion, 34...second sheath pipe, 40...post-tensioning tendon, 50...connecting member, 51...anchor plate, 51b...insertion hole, 52...spacer, 53...coupler sheath, 53b...tubular portion, 54...primary side grip, 55...coupler sleeve, 56...secondary side grip, 57...holding plate, 58...float, B...viaduct, B1...wall parapet, B2...steel girder, B3...protective fence, C...deck slab, D1...first direction, D2 ...second direction, D3...third direction, L...road, L1...uphill lane, L2...downhill lane, N1...first new lane, N2...second new lane, N3...third new lane, N4...fourth new lane, N5...fifth new lane, N6...sixth new lane, P...movable guardrail, Q...fixed guardrail, S...space, V...vehicle, X...reference line, Y...filler, Z1...first lane, Z2...second lane, Z3...third lane, Z4...fourth lane, Z5...fifth lane, Z6...sixth lane.

Claims

1. A concrete floor slab extending in a first direction and a second direction intersecting the first direction and having a thickness in a third direction intersecting both the first direction and the second direction, a concrete block having an upper surface that extends in the first direction, the second direction, and the third direction and extends obliquely upward or downward toward a center in the first direction; a sheath tube provided inside the concrete block and through which a post-tensioning steel material is inserted; Equipped with the sheath tube extends obliquely upward or obliquely downward along the upper surface toward the center in the first direction; Concrete floor slab.

2. a pretensioning steel member extending along the first direction inside the concrete block; The concrete deck according to claim 1.

3. A method for manufacturing a concrete floor slab extending in a first direction and a second direction intersecting the first direction and having a thickness in a third direction intersecting both the first direction and the second direction, A step of arranging a pretensioning steel material along the first direction and tensioning the pretensioning steel material; a step of arranging a sheath tube extending obliquely upward or downward toward the center in the first direction and through which a post-tension steel material is inserted; A process of pouring concrete onto the pretensioning steel and the sheath pipe to produce a concrete block having an upper surface that extends obliquely upward or downward along the sheath pipe toward the center in the first direction; Equipped with Manufacturing method of concrete deck slab.

4. A method for joining a plurality of precast concrete slabs to the concrete slab according to claim 1 or 2, The plurality of precast deck slabs are a central precast deck slab having a first continuous surface continuous with the upper surface and a first sheath pipe therein; an end-side precast deck slab having a second continuous surface continuous with the first continuous surface and having a second sheath pipe therein; It contains A step of inserting the post-tensioning steel material into the sheath pipe of the concrete slab to introduce prestress into the concrete slab by the post-tensioning steel material; a step of inserting a post-tensioning tendon through the first sheath tube and the second sheath tube; connecting the post-tensioning tendon extending from the first sheath tube to the post-tensioning steel member by a connecting member; tensioning the post-tensioning tendon extending from the second sheath tube; Equipped with Joining methods for concrete deck slabs.

5. Before the step of connecting to the post-tensioning steel member, erecting the concrete floor slab; a step of erecting the end side precast floor slab after the step of erecting the concrete floor slab; a step of erecting the center side precast floor slab after the step of erecting the end side precast floor slab; Equipped with The method for joining concrete slabs according to claim 4.

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