JP2023132791A - Joining method and floor slab structure - Google Patents

Abstract

To provide precast concrete floor slabs supported in two directions, one in the direction of a bridge axis and the other in the direction perpendicular to the bridge axis, a joining method for smoothly introducing pre-stress into a joint in the direction of the bridge axis and a floor slab structure, and a joining method and a floor slab structure that can reduce the number of intervening members between a pair of precast concrete floor slabs.SOLUTION: A joining method according to one embodiment comprises the steps of: placing each precast concrete floor slab 5 at a position spaced apart from a support member 3 above each of a plurality of support members 3 extending in the direction perpendicular to the bridge axis, and placing a plurality of precast concrete floor slabs 5 facing each other at a position other than directly above the support members 3; forming a joint 7 by filling a filler material 30 between a pair of precast concrete floor slabs 5 facing each other in a bridge axis direction D1; introducing pre-stress into a plurality of consecutive precast concrete floor slabs 5 in the bridge axial direction D1 by means of tensioning material 20; and filling the slabs with an inter-filling material 40.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a floor slab joining method and a floor slab structure.

JP 2019-127770A describes a joint structure for precast concrete plates. In this joint structure, the precast concrete slab has a joint end surface, and the two precast concrete slabs are arranged so that the joint end surfaces of the two precast concrete slabs face each other. A plurality of loop-shaped reinforcing members protrude from both joint end faces.

A plurality of lateral reinforcing members are arranged in a direction substantially perpendicular to the direction in which the reinforcing members protrude, and joint concrete is placed so as to embed the reinforcing members and the lateral reinforcing members. In this joint structure, a plurality of loop-shaped reinforcing members and a plurality of lateral reinforcing members are interposed between a pair of precast concrete slabs.

JP2019-127770A

By the way, in the case where a support member that supports precast concrete slabs is provided and a pair of precast concrete slabs face each other on the support member, the support member that supports the pair of precast concrete slabs and the space between the pair of precast concrete slabs is provided. An intervening member may be required that enters the area. However, in order to improve workability, it may be necessary to omit the above-mentioned intervening member. Therefore, it may be required to reduce the number of members interposed between a pair of precast concrete slabs.

An object of the present disclosure is to provide a joining method and a deck structure that can reduce the number of members interposed between a pair of precast concrete deck slabs.

The joining method according to the present disclosure connects a plurality of precast concrete deck slabs extending in a bridge axis direction, a direction perpendicular to the bridge axis perpendicular to the bridge axis direction, and a height direction perpendicular to both the bridge axis direction and the bridge axis perpendicular direction. This is a joining method that joins along the bridge axis direction. The joining method is to install each precast concrete slab at a position apart from the upper support member of a plurality of support members extending in the direction perpendicular to the bridge axis, and then connect the plurality of precast concrete slabs at a position other than directly above the support member. a step of forming joints by filling a filler between a pair of precast concrete slabs facing each other along the axial direction of the bridge, and a step of forming a joint between a pair of precast concrete slabs that are continuous in the axial direction of the bridge The method includes a step of introducing prestress into the slab using a tendon material, and a step of filling a space between the precast concrete deck slab and the support member with filler material.

In this joining method, multiple precast concrete slabs are joined along the bridge axis direction. A precast concrete slab is installed above each of the plurality of support members extending in a direction perpendicular to the bridge axis at a position separated from the support members. A pair of precast concrete slabs face each other at a position other than directly above the supporting member, and prestress is applied to the plurality of precast concrete slabs in the bridge axis direction with filler filled between the pair of precast concrete slabs. be introduced. Therefore, prestress can be introduced in the bridge axis direction without restricting the displacement of the precast concrete deck with respect to the supporting members. Further, since the pair of precast concrete slabs face each other at a position other than directly above the support member, it is possible to eliminate the need for an intervening member that is slid when introducing prestress in the bridge axis direction. Therefore, the number of members interposed between the pair of precast concrete slabs can be reduced.

The above-described joining method may include, after the step of forming the joint, a step of introducing prestress into the joint in a direction perpendicular to the bridge axis. In this case, prestress can be applied to the joint between the pair of precast concrete slabs in a direction perpendicular to the bridge axis.

The deck structure according to the present disclosure includes a plurality of support members extending in a direction perpendicular to the bridge axis, and a plurality of support members extending in the direction perpendicular to the bridge axis, the direction perpendicular to the bridge axis, and the direction perpendicular to the bridge axis and the direction perpendicular to the bridge axis. A plurality of precast concrete deck slabs arranged along the bridge axis direction while extending in the height direction of the plurality of support members and installed at a position apart from each of the upper support members; A filling material is filled between a pair of side-by-side precast concrete deck slabs, a tension material is inserted through a plurality of precast concrete deck slabs along the bridge axis direction, and a filling material is filled between the precast concrete deck slabs and supporting members. A filler material is provided. Prestress is introduced by tension members into a plurality of precast concrete deck slabs that are continuous in the axial direction of the bridge, and the plurality of precast concrete deck slabs face each other at positions other than directly above the supporting members.

In this deck structure, a precast concrete deck is installed at a position above each of a plurality of support members extending in a direction perpendicular to the bridge axis and separated from the support members. A pair of precast concrete deck slabs face each other at a position other than directly above the supporting member, and with filler filled between the pair of precast concrete deck slabs, the plurality of precast concrete deck slabs are moved in the bridge axis direction using tension members. prestress has been introduced. Therefore, prestress can be applied to the plurality of precast concrete slabs in the bridge axis direction without restricting the displacement of the precast concrete slabs with respect to the support member. Furthermore, since the pair of precast concrete slabs face each other at a position other than directly above the support member, it is possible to eliminate the need for an intervening member that is slid when introducing prestress in the bridge axis direction. Therefore, the number of members interposed between the pair of precast concrete slabs can be reduced.

According to the present disclosure, the number of members interposed between a pair of precast concrete slabs can be reduced.

FIG. 2 is a plan view showing a floor slab structure according to an embodiment. It is a bottom view showing an example of a precast concrete floor slab concerning an embodiment. FIG. 2 is a longitudinal cross-sectional view showing the joining structure of FIG. 1. FIG. FIG. 3 is a plan view showing a joining structure according to a reference example. FIG. 3 is a longitudinal cross-sectional view showing a joining structure according to a reference example.

Below, embodiments of a floor slab joining method and a floor slab structure 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 denoted by the same reference numerals, and redundant description will be omitted as appropriate. In addition, some parts of the drawings may be simplified or exaggerated for ease of understanding, and the dimensional ratios and the like are not limited to those shown in the drawings.

FIG. 1 is a plan view showing a bridge B having a site A to which a deck structure 1 and a joining method according to the present embodiment are applied. As shown in FIG. 1, the bridge B includes a plurality of girders 2 extending in the bridge axis direction D1, a plurality of support members 3 extending in the bridge axis perpendicular direction D2 between the plurality of girders 2, and a plurality of girders 2. 2 and a plurality of precast concrete deck slabs 5 arranged so as to extend in the direction D2 perpendicular to the bridge axis. The girder 2 and the support member 3 are arranged below the precast concrete slab 5. As an example, site A is a construction site on an expressway. For example, at site A, construction of a new bridge using precast concrete slabs 5 is being carried out.

The plurality of girders 2 include, for example, a plurality of steel main girders 2A and a plurality of side longitudinal girders 2B. The steel main girder 2A is thicker than the side longitudinal girder 2B. The steel main girder 2A is provided between a pair of side longitudinal girders 2B aligned in the direction D2 perpendicular to the bridge axis. As an example, two main steel girders 2A and two side longitudinal girders 2B are provided, and two main steel girders 2A are arranged between the two side longitudinal girders 2B. In the following explanation, the steel main girder 2A and the side longitudinal girder 2B will be collectively referred to as the girder 2 when there is no need to identify the steel main girder 2A and the side longitudinal girder 2B. The girder 2 is, for example, a steel girder with an upper flange, a web and a lower flange. However, the girder 2 is not limited to a steel girder, and may be a PC girder, for example.

The precast concrete floor slab 5 is a rectangular plate-shaped floor having a short side extending in the bridge axis direction D1 and a long side extending in the bridge axis perpendicular direction D2, and having a thickness in the height direction D3 (see FIG. 3). It is a version. The height direction D3 is orthogonal to both the bridge axis direction D1 and the bridge axis perpendicular direction D2. The precast concrete floor slab 5 is, for example, a UFC floor slab made of ultra high strength fiber reinforced concrete (UFC). In this case, at site A, new expressway bridge construction using UFC deck slabs will be carried out.

FIG. 2 is a bottom view of the precast concrete floor slab 5 viewed from below. As shown in FIG. 2, on the lower surface 5b of the precast concrete floor slab 5, for example, lattice-like ribs 5c are formed. The lattice rib 5c includes a plurality of bridge axis direction ribs 5d extending in the bridge axis direction D1 and a plurality of bridge axis perpendicular direction ribs 5f extending in the bridge axis perpendicular direction D2. The precast concrete floor slab 5 in which the lattice-like ribs 5c are formed on the lower surface 5b is sometimes referred to as a waffle-type floor slab.

FIG. 3 is an enlarged longitudinal sectional view of a pair of precast concrete floor slabs 5 in the floor slab structure 1 according to the present embodiment. As shown in FIG. 3, the precast concrete slab 5 has, for example, a plurality of PC steel members 6 extending in the direction D2 perpendicular to the bridge axis, and prestress is introduced in the direction D2 perpendicular to the bridge axis. For example, in the precast concrete deck slab 5, prestress is introduced only in the direction D2 perpendicular to the bridge axis by a pretension method.

The deck structure 1 includes a support member 3 and a tension material 20 that introduces prestress using a post-tension method to a plurality of precast concrete deck slabs 5 lined up in the bridge axis direction D1. The floor slab structure 1 further includes a filler 30 that is filled between a pair of precast concrete floor slabs 5 to form a joint 7, and a filler that is filled between the support member 3 and the precast concrete floor slab 5. 40. In this embodiment, the filler 30 forms the horizontal joints of the floor slab structure 1.

The support member 3 is, for example, a steel horizontal rib extending in the direction D2 perpendicular to the bridge axis. The support member 3 has an upper flange 3b, a web 3c, and a lower flange 3d. The precast concrete deck slab 5 has an end surface 5h facing the other precast concrete deck slab 5 in the bridge axis direction D1. For example, the end surface 5h has a planar shape extending in the direction D2 perpendicular to the bridge axis and in the height direction D3.

A filler 30 is filled between the pair of end surfaces 5h. For example, the filler 30 is a cement-based material that has fluidity when filled and hardens after a certain period of time from the time of filling. The filler 30 may be non-shrink mortar, cast-in-place UFC or UHPFRC (Ultra High Performance Fiber Reinforced Cementitious Composite), and various materials can be used as the filler 30.

The joint portion 7 is formed by filling a filler 30 between the pair of end surfaces 5h. At the joint 7, the pair of precast concrete floor slabs 5 face each other at a position other than directly above the support member 3. That is, the plurality of precast concrete floor slabs 5 are opposed to each other at a position other than directly above the support member 3 and apart from the support member 3 . In the present embodiment, "a position other than directly above" indicates a position other than vertically above, and indicates, for example, a state in which the position in plan view is shifted.

In the floor slab structure 1, a pair of precast concrete floor slabs 5 and a filler 30 are integrated by prestressing. The tension member 20 is inserted through a plurality of ribs 5f in the direction perpendicular to the bridge axis. In addition, the tendon material 20 may be inserted so as to cross the plurality of bridge axis direction ribs 5f, or may be inserted into the bridge axis direction ribs 5d. That is, an outer cable method may be adopted in which the tendon material 20 is exposed between a plurality of ribs 5f in the direction perpendicular to the bridge axis, or an inner cable method may be adopted in which the tendon material 20 is arranged within the ribs 5d in the bridge axis direction. may be done. For example, a sheath extending in the bridge axis direction D1 is embedded in each of the ribs 5f in the direction perpendicular to the bridge axis, and the tension material 20 is inserted into the inside of each sheath of the ribs 5f in the direction perpendicular to the bridge axis. In this way, the tension material 20 is inserted through the plurality of precast concrete deck slabs 5 lined up in the bridge axial direction D1, and is inserted into the anchoring parts (not shown) located outside the plurality of precast concrete deck slabs 5 in the bridge axial direction D1. ) is fixed by

The floor slab structure 1 includes a slip prevention member 50 that allows displacement of the plurality of precast concrete floor slabs 5 with respect to the support member 3 when prestress is introduced into the plurality of precast concrete floor slabs 5 by the tension members 20. The anti-slip member 50 includes a first anti-slip member 51 that projects downward from the precast concrete floor slab 5 and a second anti-slip member 52 that projects upward from the support member 3. For example, the first anti-slip member 51 projects downward from the rib 5f in the direction perpendicular to the bridge axis of the precast concrete deck slab 5, and the second anti-slip member 52 projects upward from the upper flange 3b of the support member 3.

Each of the length of the first anti-slip member 51 (length in the height direction D3) and the length of the second anti-slip member 52 is set in the space S between the precast concrete floor slab 5 and the support member 3. It is shorter than the height of the filled filler material 40. As shown in FIGS. 1 and 3, the space S is formed by a space holding member 8 placed on a floor assembly formed by a plurality of girders 2 and a plurality of support members 3. As an example, the space holding member 8 is a height adjustment bolt that protrudes downward from the lower surface 5b of the precast concrete floor slab 5. However, the space holding member 8 may be other than the height adjustment bolt, and the type of the space holding member 8 is not particularly limited.

A plurality of space retaining members 8 are placed on the above-mentioned floor assembly, and a space S is formed by interposing the space retaining members 8 between the floor assembly and the precast concrete floor slab 5. The filling material 40 filled in the space S is, for example, a cement-based material that has fluidity at the time of filling and hardens after a certain period of time from the time of filling. The material of the filler 40 may be the same as the material of the filler 30.

The anti-slip member 50 includes, for example, a plurality of first anti-slip members 51 and a plurality of second anti-slip members 52, and the first anti-slip member 51 and the second anti-slip member 52 are arranged in the bridge axis direction D1. They are lined up alternately. For example, the first anti-slip member 51 is a bolt (for example, an insert bolt), and the second anti-slip member 52 is a headed stud (stud dowel). However, the types of the first anti-slip member 51 and the second anti-slip member 52 are not limited to the bolts or headed studs described above, and are not particularly limited.

Next, a method for joining the precast concrete floor slab 5 according to this embodiment will be explained. First, a precast concrete floor slab 5 is prepared. At this time, as an example, prestress may be introduced into the precast concrete deck slab 5 only in the direction D2 perpendicular to the bridge axis by a pretension method in a factory for manufacturing the precast concrete deck slab 5.

In this case, before placing the concrete constituting the precast concrete slab 5, tension is applied to the PC steel material 6 arranged in the direction D2 perpendicular to the bridge axis, and after the concrete is placed and hardened, the tension is released. In this way, a plurality of precast concrete slabs 5 are prepared in which prestress is introduced only in the direction D2 perpendicular to the bridge axis (a step of introducing prestress in the direction perpendicular to the bridge axis by the pretension method).

Then, the space holding member 8 is placed on the floor assembly formed by the plurality of girders 2 and the plurality of support members 3, and the plurality of precast concrete floor slabs 5 are installed on the floor assembly. In addition, when the space holding member 8 is a height adjustment bolt, the precast concrete floor slab 5 is installed on the said floor assembly with the space holding member 8 protruding from the lower surface 5b of the precast concrete floor slab 5. At this time, a plurality of precast concrete deck slabs 5 are installed so as to be lined up in the bridge axis direction D1 above the floor assembly.

That is, each precast concrete deck slab 5 is installed at a position above each of the plurality of support members 3 extending in the direction D2 perpendicular to the bridge axis and separated from the support members 3. Then, the plurality of precast concrete floor slabs 5 are made to face each other at a position other than directly above the support member 3 (step of making the plurality of precast concrete floor slabs face each other).

Further, tension members 20 are inserted through the plurality of precast concrete floor slabs 5. At this time, the tendons 20 are inserted along the bridge axis direction D1 into the sheaths of the ribs 5f in the direction perpendicular to the bridge axis of the plurality of precast concrete deck slabs 5 that are continuous in the bridge axis direction D1 (step of inserting the tendons). At this time, as described above, the tension material 20 may be inserted so as to cross the plurality of bridge axis direction ribs 5f (outer cable method), or the tension material 20 may be inserted into the sheath provided in the bridge axis direction ribs 5d. The material 20 may be inserted through the cable (inner cable method).

A filler 30 is filled between a pair of precast concrete slabs 5 aligned in the bridge axis direction D1. Note that the tension material 20 described above may be inserted after the filling material 30 is filled. Then, the filler 30 is hardened to form a joint 7 between the pair of precast concrete slabs 5 (step of forming a joint). Note that after forming the joint portion 7, prestress may be introduced into the joint portion 7 in the direction D2 perpendicular to the bridge axis (step of introducing prestress in the direction perpendicular to the bridge axis). Specifically, a PC steel material is placed at or near the horizontal joint formed by the filler 30, and after the filler 30 hardens, prestress is introduced in the direction D2 perpendicular to the bridge axis using a post-tension method. You may.

Then, prestress by a post-tension method is introduced by tension members 20 to a plurality of precast concrete deck slabs 5 that are continuous in the bridge axis direction D1. Specifically, one end of the tension material 20 is fixed to the above-mentioned fixing section, and by applying a reaction force to the precast concrete deck slab 5 and pulling the other end of the tension material 20, the bridge axis is attached to the plurality of precast concrete deck slabs 5. Applying compressive force in direction D1 (step of introducing prestress by tendon). That is, prestress is introduced by obtaining a reaction force that pulls the tension material 20 from the precast concrete slab 5.

When introducing prestress by the tendons 20, the plurality of precast concrete floor slabs 5 can be displaced with respect to the support member 3. That is, the plurality of precast concrete floor slabs 5 and filler material 30 are slidable with respect to the support member 3. Therefore, prestress can be smoothly introduced into the plurality of precast concrete floor slabs 5 as the tension members 20 are tensioned.

As described above, after the prestress is introduced, the other end of the tension material 20 described above is fixed to the fixing section. Then, filler material 40 is filled between precast concrete slab 5 and support member 3 (step of filling filler material). After the filler material 40 is cured and the support member 3 and the filler material 40 and the filler material 40 and the precast concrete slab 5 are integrated, a series of steps is completed. More specifically, the series of steps is completed after the step of grouting the gap between the tensioned tension material 20 and the sheath.

Next, a method for joining the precast concrete slab 5 and the effects obtained from the slab structure 1 according to the present embodiment will be described. In the joining method and deck structure 1 according to this embodiment, a plurality of precast concrete deck slabs 5 are joined along the bridge axis direction D1. A precast concrete deck slab 5 is installed at a position above each of the plurality of support members 3 extending in the direction D2 perpendicular to the bridge axis and separated from the support members 3. A pair of precast concrete deck slabs 5 face each other at a position other than directly above the support member 3, and a bridge axis is attached to the plurality of precast concrete deck slabs 5 with filler 30 filled between the pair of precast concrete deck slabs 5. A prestress is introduced in direction D1. Therefore, prestress can be introduced in the bridge axis direction D1 without restraining the displacement of the precast concrete deck slab 5 with respect to the support member 3.

Moreover, since the pair of precast concrete slabs 5 face each other at a position other than directly above the support member 3, an intervening member that is slid when introducing prestress in the bridge axis direction D1 can be made unnecessary. Specifically, as shown in the reference examples of FIGS. 4 and 5, a pair of precast concrete floor slabs 5 face each other directly above the support member 3, and the joint portion 7 is provided vertically above the support member 3. In this case, the intervening member 10 and the fastening member 70 that can be slid in the bridge axis direction D1 with respect to the support member 3 may be required. By making the plurality of precast concrete slabs 5, fillers 30, and intervening members 10 slidable with respect to the supporting member 3 in a state where the intervening members 10 are not firmly fastened by the fastening members 70, the tension caused by the tension members 20 can be avoided. Accordingly, the intervening member 10 slides. By providing this intervening member 10, prestress can be smoothly introduced.

However, in the floor slab structure 1 and joining method according to the present embodiment, the pair of precast concrete slabs 5 face each other at a position other than directly above the support member 3, so that even without the intervening member 10, a plurality of precast concrete Prestress can be smoothly introduced into the floor slab 5. That is, prestress can be introduced in the bridge axis direction D1 without restraining the displacement of the precast concrete deck slab 5 with respect to the support member 3. Therefore, the number of members interposed between the pair of precast concrete slabs 5 can be reduced.

As described above, the joining method according to the present embodiment introduces prestress in the direction D2 perpendicular to the bridge axis to the joint 7 (for example, at the horizontal joint or in the vicinity of the horizontal joint) after the step of forming the joint 7. The method may also include a step of doing so. In this case, prestress can be introduced into the joint portion 7 of the pair of precast concrete deck slabs 5 in the direction D2 perpendicular to the bridge axis.

The embodiments of the joining method and floor slab structure according to the present disclosure have been described above. However, the joining method and floor slab structure according to the present disclosure are not limited to the embodiments described above, and can be modified as appropriate within the scope of the gist of the claims. That is, the structure, shape, size, material, number, and arrangement of each part of the floor slab structure, as well as the content and order of the steps of the joining method, can be changed as appropriate within the scope of the above-mentioned gist.

For example, in the embodiment described above, an example was described in which prestress is introduced in the direction D2 perpendicular to the bridge axis using a pretension method in a factory for manufacturing precast concrete deck slabs 5. However, prestressing using a post-tension method may be introduced at a location other than the factory where the precast concrete slab 5 is manufactured (for example, at the site A).

In the above-mentioned embodiment, an example was described in which the end surface 5h of the precast concrete slab 5 facing the other precast concrete slab 5 in the bridge axis direction D1 was flat. However, unevenness may be formed on the end surface 5h of the precast concrete slab 5 that faces the other precast concrete slab 5 in the bridge axis direction D1. In this case, the pair of precast concrete slabs 5 can be more firmly integrated.

In the embodiment described above, the precast concrete floor slab 5, which is a waffle-shaped floor slab in which the lattice-like ribs 5c are formed on the lower surface 5b, has been described. However, the precast concrete floor slab may be a precast concrete floor slab in which the lattice-like ribs 5c are not formed, and the type of the precast concrete floor slab can be changed as appropriate.

1... Slab structure, 2... Girder, 2A... Steel main girder, 2B... Side longitudinal girder, 3... Support member, 3b... Upper flange, 3c... Web, 3d... Lower flange, 5... Precast concrete floor slab, 5b... Lower surface, 5c... Lattice rib, 5d... Bridge axis direction rib, 5f... Bridge axis perpendicular direction rib, 5h... End face, 6... PC steel material, 7... Joint part, 8... Space holding member, 10... Intervening member, 20... Tensile material, 30... Filler material, 40... Filling material, 50... Slip prevention member, 51... First slippage prevention member, 52... Second slippage prevention member, 70... Fastening member, A... Site, B... Bridge, D1 ...Bridge axis direction, D2...Bridge axis perpendicular direction, D3...Height direction D3, S...Space.

Claims (3)

A plurality of precast concrete deck slabs extending in a bridge axis direction, a bridge axis perpendicular direction perpendicular to the bridge axis direction, and a height direction perpendicular to both the bridge axis direction and the bridge axis perpendicular direction are arranged in the bridge axis direction. A joining method of joining along the
Each of the precast concrete slabs is installed above each of the plurality of support members extending in the direction perpendicular to the bridge axis at a position separated from the support member, and the plurality of precast concrete floors are installed at a position other than directly above the support member. a step of making the plates face each other;
filling a filler between the pair of precast concrete slabs facing each other along the bridge axis direction to form a joint;
A step of introducing prestress into the plurality of precast concrete deck slabs that are continuous in the axial direction of the bridge using tendons;
filling a filler between the precast concrete floor slab and the support member;
A joining method comprising: After the step of forming the joint, a step of introducing prestress into the joint in a direction perpendicular to the bridge axis;
The joining method according to claim 1. A plurality of support members extending in a direction perpendicular to the bridge axis, which is perpendicular to the bridge axis direction;
Extending in the bridge axis direction, the bridge axis perpendicular direction, and the height direction perpendicular to both the bridge axis direction and the bridge axis perpendicular direction, and separated from the support member above each of the plurality of support members. a plurality of precast concrete slabs lined up along the bridge axis direction in a state where the slabs are installed at the same positions;
a filler filled between the pair of precast concrete slabs aligned along the bridge axis direction;
Tensile members inserted through the plurality of precast concrete slabs along the bridge axis direction;
a filler material filled between the precast concrete floor slab and the support member;
Equipped with
Prestress is introduced into the plurality of precast concrete slabs that are continuous in the axial direction of the bridge by the tension material,
The plurality of precast concrete floor slabs face each other at positions other than directly above the support member,
Floor slab structure.

Images