Method for designing stand

Abstract

To provide technology that reduces the shaking of steps even in stands having steps with small rises or long span.SOLUTION: A stand 13 provided with a step floor 15 configured from multiple precast members 21 has step floors 15 with different gradient, and a method for designing the stand 13 comprises setting the height of a rising part 30 of the precast members 21 according to the gradient of each step floor 15, setting the number of steps of a floor part of the precast members 21 according to the position where the precast members 21 are installed, and setting the necessity of a falling part 34 of the precast members 21 on the basis of bending rigidity according to the height of the rising part 30 of the precast members 21 and the number of steps of the floor part.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a method for designing a stand. [Background technology]

[0002] The stands installed in stadiums and the like have stepped floors in consideration of the line of sight of spectators. The stepped floors (hereinafter referred to as step floors) are supported by being spanned between a pair of inclined beams.

[0003] In such stands, measures are sometimes taken against vibrations caused by spectators walking, jumping, etc. For example, Patent Document 1 proposes providing vibration suppression beams with added weight between the beams (inclined large beams) that support the stepped floor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-084536 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, depending on the shape of the stand, the vibration suppression effect may not be sufficient. For example, in stands with steps that have a small rise or a long span, it is expected that the vibration of these steps will increase. [Means for solving the problem]

[0006] A design method for a stand that solves the above-mentioned problems is a design method for a stand having a stepped floor composed of a plurality of precast members, the stand having a plurality of stepped floors with different slopes, the design method including setting the height of the rising portion of the precast member according to the slope of the stepped floor, setting the number of steps of the floor portion of the precast member according to the position where the precast member is to be installed, and setting whether or not a falling portion of the precast member is required based on bending rigidity according to the height of the rising portion of the precast member and the number of steps of the floor portion. Effect of the Invention

[0007] According to the present invention, the swaying of steps can be reduced even in stands having steps with small rises or long spans. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view of the stand of one embodiment. [Diagram 2] A diagram showing an example of a precast member in the same embodiment. [Diagram 3] A diagram showing an example of a precast member in the same embodiment. [Figure 4] A diagram showing an example of a precast member in the same embodiment. [Diagram 5] A diagram showing an example of a precast member in the same embodiment. [Figure 6] A diagram showing an example of a precast member in the same embodiment. [Figure 7] A diagram showing an example of a precast member in the same embodiment. [Figure 8] A cross-sectional view showing the connecting portion of the precast members in the same embodiment. [Figure 9] A plan view showing the connecting portion of the precast members in the same embodiment. [Figure 10] 11A and 11B are diagrams illustrating an example of a design method for the stand in the embodiment. [Figure 11] 2 is a cross-sectional view showing a main part of the stand of the embodiment. FIG. [Figure 12] 2 is a cross-sectional view showing a main part of the stand of the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, one embodiment of a method for designing a stand will be described with reference to Figures 1 to 12. In this embodiment, the stand will be specifically described as a stand provided in a stadium (stadium) having a field. (stand) FIG. 1 shows an example of a stadium 11. The stadium 11 has a field 12 in the center. Stands 13 are arranged to surround the field 12. The stand 13 includes a support structure 14 and stepped floors 15A-D with different slopes. The stepped floors 15A-D have a stepped upper surface that becomes higher the further away from the field 12. Spectator seats and fences (both not shown) are provided on each of the stepped floors 15A-D.

[0010] The support structure 14 has columns 17, a raker beam (inclined large beam) 18, and horizontal beams 19 and 20. The columns 17 and the horizontal beam 19 support the raker beam 18. The raker beam 18 is inclined so as to become higher as it moves away from the field 12. The horizontal beam 19 is provided between the pair of raker beams 18.

[0011] 1, the raker beams 18 supporting each of the step floors 15A-D have different inclination angles in the step direction from the field 12 toward the highest position of the stand 13. For example, the support structure 14 includes a first raker beam 18A, a second raker beam 18B, a third raker beam 18C, and a fourth raker beam 18D in order of proximity to the field 12. The inclination angles gradually increase from the first raker beam 18A, which is closest to the field 12, to the fourth raker beam 18D, which is the furthest.

[0012] Each of the steps 15A-D is composed of precast members 21 (precast concrete). The precast members are concrete members that are manufactured in advance in a factory or the like. Each of the steps 15A-D can be composed, for example, by connecting a plurality of the precast members 21 to each other. The connection structure of the precast members 21 will be described later. The precast members 21 are prestressed by a tension member such as a PC steel strand. The first raker beam 18A supports the first step 15A composed of a plurality of the precast members 21. The second raker beam 18B, the third raker beam 18C, and the fourth raker beam 18D support the second step 15B, the third step 15C, and the fourth step 15D, respectively.

[0013] The precast members 21 constituting each of the step floors 15A to D may have different shapes. If the ratio of the height of the precast members 21 to the length in the step direction of the precast members 21 is the gradient of the precast members 21, the gradient of the precast members 21 constituting at least a part of the first step floor 15A to the fourth step floor 15D increases. However, each of the step floors 15A to D may include a precast member 21 having the same gradient as the precast members 21 included in the other step floors 15A to D. Also, in each of the step floors 15A to D, the shape of the precast members 21 is switched multiple times. In the first step floor 15A and the second step floor 15B, the height of the rise of the precast members 21 is switched multiple times. This allows the shape of these step floors 15 to be inclined in a manner close to a gentle curved surface, rather than in a planar inclination when viewed from the side. Furthermore, by reducing the gradient of the first step floor 15A and the second step floor 15B, the overall shape of the stadium 11 can be made into a mortar shape.

[0014] The stand 13 may have a different number of steps 15 at different positions in the circumferential direction surrounding the field 12. For example, three steps 15 may be provided at a predetermined position on the left side of the field 12, and four steps 15 may be provided at a predetermined position on the right side of the field 12. Furthermore, the stand 13 may be symmetrical or asymmetrical.

[0015] (Precast materials) Examples of the shapes of precast members that can form a step floor will be described with reference to Figs. 2 to 7.

[0016] Fig. 2 shows the side of the precast member 21A. The precast member 21A has a floor portion 31 and a rising portion 30 extending vertically upward relative to the plane of the floor portion 31, and is a precast member having a single floor portion formed into an L-shape on the side. Slab reinforcement bars 32 are embedded in the floor portion 31, and stirrup reinforcement bars 33 are embedded in the rising portion 30. Note that the tendons are omitted from Fig. 2. The same applies to Figs. 3 to 7 described below.

[0017] FIG. 3 shows a side view of the precast member 21B. The precast member 21B has a first floor portion 31A and a first rising portion 30A extending vertically upward with respect to the plane of the first floor portion 31A, and the first floor portion 31A and the first rising portion 30A have an L-shaped side shape. The precast member 21B also has a second floor portion 31B and a second rising portion 30B extending vertically upward with respect to the plane of the second floor portion 31B, and the second floor portion 31B and the second rising portion 30B have an L-shaped side shape. The precast member 21B is a precast member having two floor portions by connecting the first rising portion 30A and the second floor portion 31B. Slab reinforcement 32 is embedded in each of the first floor portion 31A and the second floor portion 31B. Stirrups 33 are embedded in the first rising portion 30A and the second rising portion 30B. Precast member 21B is a precast member having two floor stages, and therefore has higher bending rigidity in the vertical direction than precast member 21A having one floor stage shown in FIG. 2. For this reason, precast member 21B is less likely to shake than precast member 21A. Note that, although precast member 21B has two floor stages here, the number of floor stages may be two or more, for example, three.

[0018] 4 shows the precast member 21C. The precast member 21C has a floor portion 31, a rising portion 30 extending vertically upward relative to the plane of the floor portion 31, and a falling portion 34 extending vertically downward relative to the plane of the floor portion 31. Slab reinforcement 32 is embedded in the floor portion 31, and stirrup reinforcement 33 is embedded in the rising portion 30 and the falling portion 34.

[0019] Fig. 5 shows precast member 21C'. Precast member 21C' is similar to precast member 21 shown in Fig. 4, except that it does not have the falling portion 34 shown in Fig. 4. According to precast member 21C shown in Fig. 4, even in cases where the height of rising portion 30 cannot be sufficiently ensured, by having falling portion 34, it is possible to increase bending rigidity in the vertical direction more than precast member 21C' (see Fig. 5) that does not have falling portion 34. Therefore, precast member 21C having falling portion 34 is less likely to shake.

[0020] FIG. 6 shows a side view of the precast member 21D. The precast member 21D has a first floor portion 31A, a first rising portion 30A extending vertically upward relative to the plane of the first floor portion 31A, and a first falling portion 34A extending vertically downward relative to the plane of the first floor portion 31A. The precast member 21D also has a second floor portion 31B, a second rising portion 30B extending vertically upward relative to the plane of the second floor portion 31B, and a second falling portion 34B extending vertically downward relative to the plane of the second floor portion 31B. The precast member 21D is a precast member having two floor portions by connecting the first rising portion 30A and the second floor portion 31B.

[0021] Slab reinforcement 32 is embedded in the first floor portion 31A and the second floor portion 31B. Stirrup reinforcement 33 is embedded in the first rising portion 30A and the first falling portion 34A, and in the second rising portion 30B and the second falling portion 34B.

[0022] Fig. 7 shows a precast member 21D'. The precast member 21D' is similar to the precast member 21D shown in Fig. 6, except that it does not have the first descending portion 34A and the second descending portion 34B. The precast member 21D shown in Fig. 6 has the first descending portion 34A and the second descending portion 34B, and thus has higher bending rigidity in the vertical direction than the precast member 21D' shown in Fig. 7. Note that, although Figs. 6 and 7 show the precast member 21D having two floor stages, the number of floor stages may be two or more, for example, three.

[0023] Furthermore, precast members of shapes other than those of the precast members 21A to 21D may also be arranged in the stand 13. For example, at the tip of the step floor 15, a precast member or the like (not shown) having a wall that divides the spectator seats is provided.

[0024] The precast members 21 constituting each stepped floor 15 include those having different lengths in the step direction of the upper surface 35 and different heights of the rising portions 30, even if they are of the same type of shape classified according to the number of steps of the floor portion 31 and the presence or absence of the falling portion 34. For example, a precast member 21C having one floor portion 31 and a falling portion 34 includes multiple precast members 21C having falling portions 34 with different heights.

[0025] In the present invention, the shapes of the precast members are not limited to those shown in Figures 2 to 7. For example, the rising portion of the precast member may be provided at a position other than the positions shown in the figures, so long as it extends upward relative to the plane of the floor. Also, the falling portion of the precast member may be provided at a position other than the positions shown in the figures, so long as it extends downward relative to the plane of the floor. Furthermore, the rising portion and the falling portion of the precast member do not have to be perpendicular to the floor.

[0026] (connected structure) Next, an example of a connection structure of precast members will be described with reference to Fig. 8. For convenience of explanation, the connection structure in which the precast members 21A shown in Fig. 2 are connected to each other will be described below, but the connection structure between the precast members is not limited to that shown in Fig. 8.

[0027] Fig. 8 shows a connecting structure 38 when the precast members 21A shown in Fig. 2 are connected to each other. The connecting structure 38 has a plurality of connecting parts 39. The connecting parts 39 include inserts 41, strands 42, and anchor bolts 43. The connecting parts 39 are arranged in the width direction from one raker beam 18 (see Fig. 1) supporting the precast members 21A to the other raker beam 18.

[0028] An insert 41 is embedded in the lower end of the floor portion 31 of the precast member 21A located in the upper stage. The insert 41 is held by tendons 42 embedded in the precast member 21.

[0029] At the upper end of the first rising portion 30A of the floor portion 31 of the precast member 21A located at the lower stage, a hole 44 is formed which opens at the upper surface of the first rising portion 30A. An anchor bolt 43 is inserted into the hole 44, and the anchor bolt 43 inserted into the hole 44 is fixed by a filler 45 such as non-shrink mortar which is filled in the hole 44.

[0030] The female thread of the insert 41 provided in the upper precast member 21A is screwed into the male thread of an anchor bolt 43 fixed to the lower precast member 21. A packing material 46 and a sealing material 47 are provided between the upper precast member 21A and the lower precast member 21A.

[0031] Fig. 9 is a diagram showing a part of the step floor 15 having the connecting structure 38 shown in Fig. 8, and is a plan view of the end of the step floor 15 seen from above. The raker beams 18 support the precast members 21 on their upper surfaces. For the sake of explanation, only the anchor bolts 43 are shown in Fig. 9.

[0032] In FIG. 9, each connecting portion 39 (not shown) having an anchor bolt 43 is densely arranged in the width direction of the precast member 21 at the end of the width direction of the precast member 21, in other words, at the raker beam 18 side. That is, the connecting portions 39 are arranged at intervals of length L1 in the center of the width direction of the precast member 21. Also, the connecting portions 39 are arranged at intervals of length L2, which is shorter than length L1, at the end of the width direction of the precast member 21. By densely arranging the connecting portions 39 at the end of the precast member 21A in this way, even if the span of the precast member 21A in the width direction is long, it is possible to reduce the deviation between the steps during vertical displacement. Note that the connecting portions 39 are not limited to the above-mentioned arrangement, and may be arranged evenly in the width direction of the precast member in a part of the stand 13 (see FIG. 1), for example.

[0033] (Stand design method) Next, a method for designing a stand will be described with reference to Figures 1 and 10. Figure 10 is a diagram showing an example of a method for designing a stand.

[0034] First, the gradient of the steps 15 is set in accordance with the shape of the stadium 11 (Step S1). Specifically, the gradient is set so that it increases from the first step 15A to the fourth step 15D.

[0035] Next, the shape of the precast members 21 is set according to the vertical rigidity required for each step floor 15. Specifically, the height of the rising portion 30 of the precast members 21 is set according to the gradient of each step floor 15 set in step S1 (step S2). At this time, the length of the upper surface 35 of the precast members 21 in the step direction is also set. In other words, the gradient of the precast members 21 is set in step S2. If one step floor 15 has different gradients, the height of the rising portion 30 of the precast members 21 is set for each gradient.

[0036] Then, it is determined whether or not the number of stages of the floor portions 31 of the precast member 21 can be set to two or more (step S3). Furthermore, based on the bending rigidity according to the height of the rising portion 30 and the number of steps of the floor portion 31 of the precast member 21, it is determined whether or not the falling portion 34 is required (step S4).

[0037] Then, the shape of the precast member 21 is set (step S5). The type of shape is set based on the height of the rising portion 30 of the precast member 21, the determination result of whether the number of steps of the floor portion 31 of the precast member 21 can be set to two or more, the determination result of whether the falling portion 34 is necessary, etc., which were set in steps S2 to S4.

[0038] It is determined whether the shape of the precast members 21 has been set for all positions where the precast members 21 will be installed (Step S6). If there are any positions in the stand 13 where the shape of the precast members 21 has not been set (Step S6: NO), the process returns to Step S2, and the shape of the precast members 21 is set for the remaining positions (Steps S2 to S5). On the other hand, if it is determined that the shape of the precast members 21 has been set for all installation positions (Step S6: YES), the layout of the precast members 21 is completed.

[0039] With reference to Figures 11 and 12, the precast members 21 arranged based on the above-mentioned stand design method will be described. Figure 11 shows an example of a first step floor 15A. In the first step floor 15A with a small gradient, a precast member 21D having two floor sections 31 and a descending portion 34, and a precast member 21C having one floor section 31 and a descending portion 34 are installed. The precast members 21 are installed at the lower and upper ends of the first step floor 15A. Also, cast-in-place concrete 49 is provided at the tip of the first step floor 15A.

[0040] In precast member 21D installed on first step floor 15A, the height of rising portion 30 changes twice in the step direction. In other words, precast members 21E, 21F, and 21G of a two-step floor with rising portions 30 of different heights are installed in the step direction. Note that precast members 21E, 21F, and 21G are precast members 21D with rising portions 30 of different heights, and when describing these without distinguishing between them, they will simply be referred to as precast member 21D.

[0041] Precast members 21E, 21F, 21G have rising portions 30 that increase in height from the bottom up. Precast member 21C located at the bottom end of first step floor 15A has the same height of rising portion 30 as precast member 21E to which it is connected. Precast member 21C located at the top end of first step floor 15A has the same height of rising portion 30 as precast member 21G to which it is connected.

[0042] 12 shows an example of the second step floor 15B. Compared to the first step floor 15A, the precast member 21 provided on the second step floor 15B has a higher rising portion 30. A precast member 21B having two floor portions 31 and no falling portion 34, and a precast member 21C having one floor portion 31 and a falling portion 34 are installed on this second step floor 15B. For example, a precast member 21C having one floor portion 31 and cast-in-place concrete 49 may be provided on the lower end of the second step floor 15B.

[0043] Furthermore, in the second step floor 15B, the height of the rising portion 30 of the precast member 21B changes twice. In other words, precast members 21H, 21J, and 21K having two floor stages with rising portions 30 of different heights are installed in the step direction. Note that the precast members 21H, 21J, and 21K are precast members 21B having rising portions 30 of different heights, and when the description does not need to distinguish between them, they will simply be referred to as precast members 21B.

[0044] Precast members 21H, 21J, and 21K have rising portions 30 that increase in height from the bottom up. Precast member 21C at the bottom end has rising portion 30 that is the same height as precast member 21H to which it is connected.

[0045] As described above, according to the above embodiment, the following effects can be obtained. (1) According to the above embodiment, when laying out the precast members 21 on the stepped floor 15, the height of the rising portions 30 of the precast members 21 is set, and the number of steps of the floor portions 31 of the precast members 21 is set for each installation position. Then, based on the bending rigidity according to the height of the rising portions 30 of the precast members 21 and the number of steps of the floor portions 31, it is determined whether or not the falling portions 34 of the precast members 21 are necessary. This makes it possible to improve the aesthetic appearance of the stadium 11, for example by giving the stadium 11 a cone-like shape, while also increasing the bending rigidity of the precast members 21 in the vertical direction. This reduces shaking caused by spectators walking, etc.

[0046] (2) In the above embodiment, the anchor bolts 43 connecting the precast members 21 to each other are arranged densely at the ends where the gap between the steps increases when the precast members 21 are vertically displaced. This makes it possible to reduce the gap between the steps and reduce shaking.

[0047] (3) In the above embodiment, the precast members 21 of different shapes constituting the stepped floor 15 include a precast member 21D having two floor sections 31, and having a first descending portion 34A extending downward relative to the plane of the first floor section 31A and a second descending portion 34B extending downward relative to the plane of the second floor section 31B. Therefore, the precast members 21 with high bending rigidity can be arranged even on the first stepped floor 15A with a small gradient.

[0048] The above-described embodiment can be modified as follows: Each embodiment and the following modified examples can be combined with each other to the extent that there is no technical contradiction. The structure of the stadium is not limited to the structure of the stadium 11 in the above embodiment. For example, the stadium 11 has four stepped floors 15, but is not limited to this configuration.

[0049] In the above embodiment, the type of shape of the precast member 21 is not particularly limited as long as there are multiple types. The type of shape of the precast member 21 preferably includes at least a precast member 21D having two floor sections 31 and a descending section 34. The type of shape of the precast member 21 may also include a precast member 21 having a floor section 31 in three or more stages.

[0050] In the above embodiment, the anchor bolts 43 are closely spaced at the widthwise ends of the precast member 21, but this is not limited to the above. The anchor bolts 43 may be evenly spaced as long as it can reduce the misalignment between the steps during vertical displacement.

[0051] In the above embodiment, the stand is embodied as the stand 13 provided in the stadium 11. Alternatively, the stand may be provided in other buildings having stepped floors, such as a theater or a concert venue.

[0052] The layout of the precast members 21 in the above embodiment may be implemented, for example, by using an information processing device including a computer. Specifically, for example, at least a part of the procedure for setting the layout of the precast members 21 may be automatically executed using various input data. The information processing device includes, for example, a calculation device such as a CPU, a storage unit, an input device such as a mouse or a touch panel, and an output device such as a display. The storage unit stores a program for executing at least a part of the procedure for setting the layout. For example, the calculation device executes the program to perform a first process for setting the number of steps of the floor part of the precast members, a second process for setting the height of the rising part of the precast members, and a third process for determining whether or not a falling part is required. When the information processing device performs the first process, the second process, and the third process, the information processing device prestores information such as the gradient of the stand 13, information indicating the conditions for transporting and lifting the precast members 21 with a two-tiered floor, and information on the weight of the precast members 21.

[0053] Next, the technical ideas that can be understood from the above embodiment and other examples will be described below. (A) A method for designing a stand as described in claim 1, in which a precast member having two or more floor sections and having the descending sections each located below the rising sections is placed on the step with the smallest slope among the plurality of step floors.

[0054] (B) A method for designing a stand described in (A), in which a plurality of precast members having rising portions of different heights are placed on the step floor with the smallest slope. [Explanation of symbols]

[0055] 11...stadium, 12...field, 13...stand, 14...supporting structure, 15...step floor, 15A to 15D...first step floor to fourth step floor, 17...column, 18...raker beam, 18A to 18D...first step beam to fourth step beam, 21...precast member, 21A...precast member, 21A to 21K...precast member, 30, 30A, 30B...rising portion, 31, 31A, 31B...floor portion, 32...slab reinforcement, 33...stirrup reinforcement, 34, 34A, 34B...falling portion, 35...top surface, 38...connecting structure, 39...connecting portion, 41...insert, 42...anchor reinforcement, 43...anchor bolt, 45...filling material, 46...packing material, 47...sealing material, 49...cast-in-place concrete.

Claims

1. A method for designing a stand having a stepped floor composed of a plurality of precast members, comprising the steps of: The stand has a plurality of step floors having different slopes, The design method includes: Setting the height of the rising portion of the precast member according to the gradient of each step floor; Setting the number of steps of the floor portion of the precast member according to the position where the precast member is installed; A stand design method including determining whether or not a descending portion of the precast member is necessary based on bending rigidity corresponding to the height of the ascending portion of the precast member and the number of steps of the floor portion.

2. The stand design method according to claim 1 , wherein the intervals between the plurality of anchor bolts connecting the pair of precast members are made smaller at the ends of the precast members.

3. 3. A stand design method as described in claim 1 or 2, wherein the precast members constituting the stepped floor include precast members having two or more steps of the floor section and having downward portions extending downward relative to the planes of each of the floor sections.

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