Deck roof structure and design method for deck roof structure

Abstract

This prevents the deck plates from coming apart when they deform due to temperature increases caused by fire or other factors. [Solution] A deck roof structure 100 is provided, comprising a deck plate 1 having a horizontal section 2 and a pair of left and right fitting ribs 4, 5 formed on both sides of the widthwise edge of the horizontal section 2; a base section 72 and a tight frame 70 having a plurality of protrusions 71 that protrude from the base section 72 and contact the lower surface of the horizontal section 2, on which the deck plate 1 is laid, wherein the amount of deformation within the cross-section of the deck plate 1 is δ, and the clearance between the lower ends of the fitting ribs 4, 5 and the upper surface of the base section 72 of the tight frame 70 is c, and δ > c.

Description

Technical Field

[0001] The present invention relates to a deck roof structure that constitutes a roof of a building and a design method of the deck roof structure.

Background Art

[0002] As a structure using a flat deck plate (roof slab) as a roof of a steel-frame building, the one described in Patent Document 1 is known. In the deck roof structure described in Patent Document 1, the deck plate is attached to the building frame via a tight frame.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the deck roof structure described in Patent Document 1, the space between the leg-shaped rib portions (reinforcing ribs) of the deck plate may be flat. When the temperature of the deck plate (steel material) rises due to a fire or the like under the action of a bending moment caused by a load, there is a problem that the amount of deformation increases due to a decrease in the bearing capacity.

[0005] When the amount of deformation in the cross section increases, the joints between adjacent decks come off, leading to problems such as the roof not being able to exhibit the expected load support force and gaps occurring in the roof, so it is necessary to avoid such situations. In addition, when the roof is a fire-resistant structure roof, it is necessary to adopt the roof structure described in Ministry of Construction Notice No. 1399 based on the provisions of Article 2, Paragraph 7 of the Building Standards Law. To obtain the ministerial certification for such a roof structure, it is necessary to conduct a test in accordance with the "Method of Fire and Heat Resistance Performance Test and Evaluation" issued by the designated performance evaluation agency and pass the test. As a specific example, flame shielding performance is required, and if a gap or the like occurs in the roof and an event such as fire leakage is confirmed, it will be judged as a failure.

[0006] Therefore, the present invention aims to provide a deck roof structure and a method for designing a deck roof structure that can prevent the deck plates from coming apart when they deform due to temperature rise caused by fire or the like. [Means for solving the problem]

[0007] [1] A deck roof structure comprising: a deck plate having a horizontal section and a pair of left and right fitting ribs formed on both edges of the horizontal section in the width direction; a base section and a tight frame having a plurality of protrusions that protrude from the base section and contact the lower surface of the horizontal section, on which the deck plate is laid, wherein the clearance c between the lower end of the fitting ribs and the upper surface of the base section of the tight frame is 5.93 mm or less. [2] The deck roof structure according to [1], characterized in that δ is the amount of deformation within the cross section of the deck plate, and c is the clearance between the lower end of the fitting rib and the upper surface of the base portion of the tight frame, and δ > c. [3] The deck roof structure according to [1] or [2], characterized in that the deck plate has a plurality of V-shaped ribs formed on the horizontal portion and extending in the longitudinal direction, and the height of the V-shaped ribs is 4.0 mm or more and 12 mm or less. [4] The deck roof structure according to [1] or [2], characterized in that the deck plate has reinforcing ribs formed on the horizontal portion and extending in the longitudinal direction, and the distance in the width direction between the reinforcing ribs and the fitting ribs of the deck plate is 200 mm or more and 220 mm or less. [5] The deck roof structure according to [1] or [2], characterized in that the thickness of the deck plate is 0.8 mm or more and 1.6 mm or less. [6] The deck roof structure according to [1] or [2], characterized in that the height of the deck plate is 75 mm or more and 120 mm or less.

[0008] [7] A method for designing a deck roof structure comprising: a deck plate having a horizontal portion and a pair of left and right fitting ribs formed on both edges of the horizontal portion in the width direction; a base portion and a tight frame having a plurality of protrusions that protrude from the base portion and contact the lower surface of the horizontal portion, on which the deck plate is laid, characterized in that the design is such that δ > c, where δ is the amount of deformation within the cross section of the deck plate and c is the clearance between the lower end of the fitting ribs and the upper surface of the base portion of the tight frame. [Effects of the Invention]

[0009] According to the present invention, in a deck roof structure in which deck plates are fitted together using interlocking ribs, it is possible to prevent the deck plates from coming apart even if the deck plates deform due to a temperature rise caused by a fire or the like. [Brief explanation of the drawing]

[0010] [Figure 1] This is a front view showing a deck roof structure according to an embodiment of the present invention, viewed horizontally along the longitudinal direction of the deck plate. [Figure 2] This is a cross-sectional view of a deck roof structure with a riser installed between the main frame and the tight frame. [Figure 3] This is a front view of a tight frame according to an embodiment of the present invention. [Figure 4] This is a front view of a deck plate according to an embodiment of the present invention. [Figure 5] This diagram shows how the convex portion of the tight frame contacts the flat portion and the adjacent slanted edge. [Figure 6] This diagram shows a situation where the flat portion of the deck plate is larger than the support surface of the tight frame, resulting in a poor fit. [Figure 7] This is an enlarged view illustrating the angle DPr between the flat portion of the deck plate and the adjacent hypotenuse, and the angle TFr between the inclined surface of the convex portion of the tight frame. [Figure 8]It is a diagram showing a state when the height TFh of the title frame is lower than the height DPh of the deck plate 1. [Figure 9] It is a diagram showing a state in which in-plane deformation has occurred in the deck plate in the deck roof structure. [Figure 10] It is a diagram showing a state in which by reducing the clearance, the fitting rib and the title frame come into contact with each other and fitting disengagement is avoided. [Figure 11] It is a diagram showing a model of the deck plate used in the analysis. [Figure 12] It is a diagram for explaining the in-plane deformation amount δ in the model of the deck plate. [Figure 13] It is a graph showing the relationship between the in-plane deformation amount δ of the deck plate and the heating time. [Figure 14] It is a front view of a deck roof structure having fitting ribs of other forms.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant descriptions are omitted.

[0012] The deck roof structure of the present invention constitutes, for example, the roof of a steel-frame building and is provided on the building frame such as beams and main houses of the building. As shown in FIG. 1, the deck roof structure 100 has a title frame 70 fixed to the frame 90 and a deck plate 1 fixed to the title frame 70.

[0013] The frame 90 of this embodiment is a steel H-section consisting of a flange 91 and a web 92. The steel H-section extends in a direction orthogonal to the longitudinal direction of the deck plate 1 (the direction along the plane of FIG. 1), and a plurality of them are installed at a predetermined interval in a direction orthogonal to the longitudinal direction of the deck plate 1. Further, as shown in FIG. 2, there is also a case where a light steel section, a channel steel, or the like is installed as a spacer 93 for aligning the height levels between the frame 90 and the tight frame 70.

[0014] As shown in FIG. 1, the tight frame 70 is a fitting for joining the deck plate 1 and the frame 90, and has a base portion 72 joined to the frame 90 and a plurality of convex portions 71 protruding from the base portion 72. As shown in FIGS. 1 and 3, the convex portion 71 of the tight frame of this embodiment has a trapezoidal shape, and has a support surface portion 73 that is in surface contact with the deck plate 1 and a slope surface portion 74 that is a slope connecting the support surface portion 73 and the base portion 72. The tight frame 70 is, for example, 30 mm to 100 mm in width and is formed of a strip steel, a zinc iron plate, or the like with a plate thickness of 2.3 mm to 4.5 mm The plate thickness is set as a plate thickness corresponding to thin plates and medium plates that are easy to bend in consideration of manufacturability.

[0015] The deck plate 1 is bent from a thin steel plate of about 0.8 mm to 1.6 mm that has been subjected to rust prevention treatment such as a hot-dip galvanized steel sheet (JIS G3302), and is a steel plate formed into a rectangular shape in plan view with a predetermined length according to the shape of the building. The length of the deck plate 1 varies depending on the thickness of the steel plate, but generally it is 1.0 m to 13 m.

[0016] As shown in FIGS. 1 and 4, the deck plate 1 is a substantially flat deck plate, and includes a rectangular flat horizontal portion 2, a reinforcing rib 3 protruding vertically (vertically) along the longitudinal direction from one side (lower surface) of the horizontal portion 2, and a pair of left and right fitting ribs 4 and 5 formed along the edges on both sides in the deck plate width direction (horizontal direction orthogonal to the extending direction of the reinforcing rib 3) of the horizontal portion 2 and having a shape that fits with each other.

[0017] In this embodiment, the deck plate 1 has a single reinforcing rib 3 protruding from the center of the horizontal section 2, and the horizontal section 2 is divided into a first horizontal section 21 and a second horizontal section 22 at this reinforcing rib 3. Of course, there may be multiple reinforcing ribs 3, and the horizontal section 2 may also be divided into three or more sections.

[0018] (Horizontal part) The first horizontal section 21 and the second horizontal section 22 are flat plate-shaped members positioned on the left and right sides of the reinforcing rib 3, and have irregularities formed along their longitudinal direction by being bent to increase bending rigidity and bending strength.

[0019] In the horizontal section 2 according to this embodiment, as shown in Figure 4, two V-shaped ribs 23, which are downward-convex protrusions with a trapezoidal cross-section, are formed on both the first horizontal section 21 and the second horizontal section 22 as irregularities to increase bending rigidity and bending strength. The two V-shaped ribs 23 form a mountain-shaped section 24 on the horizontal section 2 that is convex upward. In other words, the deck plate 1 has a plurality of reinforcing ribs 3 and mountain-shaped sections 24 between the reinforcing ribs 3. The mountain-shaped portion 24 has a horizontal surface, and a flat plate portion 25 is formed between a pair of mountain-shaped ribs 23. Alternatively, both the first horizontal portion 21 and the second horizontal portion 22 may have two mountain-shaped ribs 23 formed thereon, which have a trapezoidal cross-section and are convex upwards relative to the first horizontal portion 21 and the second horizontal portion 22.

[0020] A flat plate section 25 is provided between the two V-shaped ribs 23, and the deck plate 1 is supported by the tight frame 70 by the surface contact between the support surface section 73 of the tight frame 70 and the flat plate section 25.

[0021] As an example of the irregularities provided on the horizontal section 2, the above-described V-shaped rib 23 was used, but protrusions with a triangular or polygonal cross-section may also be used. In other words, the irregularities provided on the horizontal section 2 may be V-shaped ribs with protrusions or depressions of other shapes, as long as they are irregularities that can be bent along the longitudinal direction to increase bending rigidity and bending strength.

[0022] (Reinforcement ribs) The reinforcing rib 3 is vertically installed in the center of one side of the horizontal section 2 (between the first horizontal section 21 and the second horizontal section 22) and consists of a closed section 30 where two flat steel plates overlap, and a reinforcing rib section 31 with a triangular cross-section formed at the tip of this closed section 30. It has the function of improving the bending rigidity and bending strength of the horizontal section 2 in the longitudinal direction. Although the reinforcing rib section 31 is exemplified as having a triangular cross-section, it may also be in the shape of an inverted T or a polygon. (First mating rib) The first fitting rib 4, which is the right-hand fitting rib of the pair of fitting ribs shown in Figure 4, is composed of a flat plate-shaped first web portion 40 that rises perpendicularly to the plane of the first horizontal portion 21, which is in the out-of-plane direction of the horizontal portion 2; an inclined portion 41 (web portion) that slopes downward inward (towards the side adjacent to the reinforcing rib 3, the same applies hereinafter) from the tip of the first web portion 40 in the state shown in Figure 4; a first flange portion 42 that is horizontally continuous from the tip of the inclined portion 41; a first folded portion 43 that slopes upward from the tip of the first flange portion 42 in the state shown in Figure 4; and a guide inclined portion 44 that slopes in the opposite direction from the first folded portion 43 from the tip of the first folded portion 43. The first flange portion 42 protrudes out of the plane of the first web portion 40 and in the opposite direction to the second fitting rib 5. The first folded portion 43 is inclined out of the plane of the first flange portion 42 and toward the horizontal portion 2.

[0023] This first fitting rib 4 has the function of connecting the deck plates 1 together by fitting with the second fitting rib 5 of the adjacent deck plate 1.

[0024] Furthermore, the corners at the joints of the first web section 40, the inclined section 41, the flange section 42, the first folded section 43, and the guide inclined section 44 are all curved and bent to form rounded corners.

[0025] Furthermore, in the deck plate 1 according to the present invention, the inclined portion 41, which is part of the web portion, may not be inclined and may be continuous on the same plane as the first web portion 40, and the guide inclined portion 44, which is part of the flange portion, may not be present. However, even in the deck plate 1 according to the present invention, the first folded portion 43, which is the folded portion of the flange portion, is essential. If the first folded portion 43, which is the folded portion of the flange portion, is present, it becomes possible to lift one of the deck plates and fit the deck plates together.

[0026] (Second mating rib) The second fitting rib 5, which is the left fitting rib of the pair of fitting ribs shown in Figure 4, is composed of a flat plate-shaped second web portion 50 that rises perpendicularly to the plane of the second horizontal portion 22, which is in the out-of-plane direction of the horizontal portion 2; a second flange portion 51 that slopes inward and downward from the tip of the second web portion 50 in the state shown in Figure 4; and a pressing inclined portion 52 that slopes upward from the tip of the second flange portion 51 in the state shown in Figure 4. The second flange portion 51 extends out of plane from the second web portion 50 and in the same direction as the first flange portion 42 of the first fitting rib 4. The pressing inclined portion 52 is inclined out of plane from the second flange portion 51 and toward the horizontal portion 2.

[0027] Furthermore, the inclination height of the second flange portion 51 is higher than the inclination height of the first folded portion 43 and the guide inclination portion 44, and the inclination angle of the second flange portion 51 is different from the inclination angle of the first folded portion 43 and the guide inclination portion 44, and is gentler than these inclination angles in the state shown in Figure 3.

[0028] As shown in each figure, similar to the first fitting rib 4, the corners of the second web portion 50, the second flange portion 51, and the pressing inclined portion 52 of the second fitting rib 5 are all curved and bent to form rounded corners.

[0029] In the deck plate according to the present invention, the second flange portion 51 may be horizontal instead of inclined. However, even in the deck plate according to the present invention, the pressing inclined portion 52, which is the folded portion of the second flange portion 51, is essential because it fits with the first folded portion 43 of the first fitting rib 4. In short, in the deck plate according to the present invention, each flange portion must have a folded portion that is inclined out of the plane of the flange portion to prevent it from shifting in the short direction.

[0030] Furthermore, as shown in Figure 4, the horizontal distance D1 between the first web portion 40 of the first fitting rib 4 and the point where the inclination of the first folded portion 43, which is its folded portion, begins is approximately equal to the horizontal distance D2 between the outer surface of the second web portion 50 of the second fitting rib 5 and the outer surface of the point where the inclination of the pressing inclined portion 52, which is its folded portion, begins. Therefore, even if there is some error in the machining accuracy of the inclination angle of the first folded portion 43 and the pressing inclined portion 52, the second fitting rib 5 fits snugly into the first fitting rib 4, and the first web portion 40 and the second web portion 50 come into surface contact.

[0031] Next, the detailed shapes of the deck plate 1 and the tight frame 70 will be described. The detailed shapes described below are primarily intended to suppress misalignment of the deck plate 1 and the tight frame 70 during construction.

[0032] The deck plate 1 is formed such that the flat plate portion 25, which is the horizontal surface of the mountain-shaped portion 24, is in surface contact with the support surface portion 73, which is the horizontal surface of the convex portion 71 of the tight frame 70. Regarding the support surface portion 73 of the flat portion 25 and the convex portion 71 of the deck plate 1, the width dimension DPw of the flat portion 25 and the width dimension TFw of the support surface portion 73 are formed to satisfy equation (1). DPw≧TFw ···(1)

[0033] If equation (1) is not satisfied, that is, if the flat portion 25 of the deck plate 1 is smaller than the support surface portion 73 of the convex portion 71, the convex portion 71 of the tight frame 70 will come into contact with the flat portion 25 and the adjacent hypotenuse 26, as shown in Figure 5, and will not be stable. Furthermore, when joining from above with self-drilling screws or the like, out-of-plane deformation will occur in the deck plate 1, or the self-drilling screws may not reach the tight frame 70, making joining difficult. On the other hand, if the flat portion 25 of the deck plate 1 is extremely large, the arrangement will be as shown in Figure 6, and the effect of suppressing misalignment cannot be expected. Therefore, considering the suppression of construction errors and misalignment, it is desirable to use the dimensions within the range of equation (2). 0mm ≤ DPw - TFw ≤ 10mm ···(2)

[0034] Here, according to JIS G 3352 (Deck Plate), the dimensional tolerance for the effective product width of a deck plate is +8 mm, -2 mm. Since a variation of 10 mm in absolute value is possible, the upper limit of DPw-TFw in equation (2) was set to 10 mm.

[0035] As shown in Figure 7, the angle DPr between the flat portion 25 of the deck plate 1 (mountain-shaped portion 24) and the adjacent hypotenuse 26, and the angle TFr between the inclined surface 74 of the convex portion 71 of the tight frame 70 and the support surface 73 are formed to satisfy equation (3). 10°≦DPr≦TFr≦90° ···(3)

[0036] If the angle DPr on the deck plate 1 side is shallow, the effect of suppressing misalignment cannot be expected. Even considering the frictional resistance generated between the deck plate 1 and the tight frame 70 due to the weight of the deck plate 1, it is desirable that the angle DPr on the deck plate 1 side be at least 10° or more. Furthermore, if the angle TFr on the tight frame 70 side is shallower than the angle DPr on the deck plate 1 side, the protrusion 71 of the tight frame 70 will come into contact with the slanted side 26 of the unevenness of the deck plate 1, resulting in an unstable fit. On the other hand, if the angle TFr on the tight frame 70 side is 90° or more, the tight frame will take on an inverted triangular shape, making it impossible to stably support the load of the deck plate 1. Therefore, it is desirable that angles DPr and TFr satisfy equation (3).

[0037] Furthermore, the height TFh of the tight frame 70 shown in Figure 3 and the height DPh of the deck plate 1 shown in Figure 4 must satisfy equation (4). DPh ≤ TFh ···(4)

[0038] If equation (4) is not satisfied, as shown in Figure 8, the reinforcing rib 3 of the deck plate 1 and the base portion 72 of the tight frame 70 will come into contact, so the deck plate 1 will no longer be supported by the flat plate portion 25, making it difficult to position the deck plate 1. Furthermore, when joining from above with self-drilling screws or the like, out-of-plane deformation may occur in the deck plate 1, or the self-drilling screws may not reach the tight frame 70, making joining difficult.

[0039] <Construction method> Next, the construction method for the deck roof structure 100 described above will be explained. The construction method for the deck roof structure includes a tight frame fixing process and a deck plate laying process.

[0040] In the tight frame fixing process, the base portion 72 of the tight frame 70 is fixed to the structural frame 90 by welding, screws, or other appropriate mounting means. In the deck plate laying process, the deck plate 1 is laid on the tight frame 70 such that the support surface portion 73 of the convex portion 71 of the tight frame 70 is in surface contact with the lower surface of the flat portion 25 of the deck plate 1.

[0041] The method of joining the deck plate 1 and the tight frame 70, and the method of joining the tight frame 70 and the structural frame 90 (purlin) may be by self-drilling screws, fillet welding, or driven rivets.

[0042] Incidentally, the deck plate 1 deforms due to, for example, a temperature rise caused by a fire or the generation of a bending moment due to a load. Figure 9 shows how the deck plate 1 undergoes cross-sectional deformation in the deck roof structure 100. As shown in Figure 9, the cross-sectional deformation of the deck plate 1 causes the adjacent deck plates 1 to become disengaged.

[0043] The inventors believed that even if deformation occurs within the cross-section of the deck plate 1, disengagement could be avoided by adjusting the clearance between the lower ends of the fitting ribs 4 and 5 of the deck plate 1 and the upper surface of the base portion 72 of the tight frame 70.

[0044] Therefore, the inventors determined the amount of internal deformation δ of the deck plate 1 through the analysis described later, and designed the deck plate 1 to satisfy the following equation (1) when the clearance between the lower ends of the fitting ribs 4 and 5 and the upper surface of the base portion 72 of the tight frame 70 is c (see Figure 1) and the amount of internal deformation δ. δ>c ···(5) In other words, by designing the deck roof structure to satisfy equation (5), even if deformation occurs in the cross-section of the deck plate 1, as shown in Figure 10, the fitting ribs 4 of the deformed deck plate come into contact with the base portion 72 of the tight frame 70, thereby preventing the fitting ribs 4 and 5 from coming loose.

[0045] <Calculation of in-section deformation of deck plate through analysis> Next, we will explain the analysis performed to calculate the amount of deformation δ within the cross-section of the deck plate. The cross-sectional deformation δ is the deformation confirmed by FEM analysis, which models the deck plate shape and reproduces the temperature rise due to fire and the generation of bending moment due to load. The model was modeled with a unit width of 100 mm, taking symmetry into consideration. For the heating temperature, the temperature distribution of the deck plate was represented in 5 categories based on the results of a heat conduction analysis simulating a fire on the lower floor, and the temperature rise of the deck plate was applied linearly so that the temperature after 30 minutes (1800 seconds) conforms to the ISO standard heating curve. For the load, following the load conditions used in the performance evaluation test for obtaining ministerial certification as a fire-resistant roof conforming to Ministry of Construction Notification No. 1399 (in accordance with the Fire Resistance Performance Test and Evaluation Work Method Manual), 1 m 2 A constant load of 65 kg was applied to each unit.

[0046] In the FEM analysis, as shown in Figure 11, the amount of deformation δ within the cross section was compared by changing the height of the uneven shape (mountain-shaped rib 23) of the horizontal section 2 as a parameter. In other words, the inventors assumed that the amount of deformation δ within the cross section would change depending on the height of the uneven shape, and performed analyses on multiple models with different uneven shapes.

[0047] Figure 11(a) is a model of a deck plate 1 with no irregularities on the horizontal section 2 (Model 1). Figure 11(b) shows a model of deck plate 1 with a ridge height (height of the V-shaped rib 23) of 4 mm (Model 2). Figure 11(c) shows a model of deck plate 1 with a surface height of 8 mm (Model 3). Figure 11(d) shows a model of deck plate 1 with a surface height of 12 mm (Model 4). The height of the unevenness is the vertical distance from the horizontal surface 2 (top surface) of the deck plate 1 to the bottom surface of the V-shaped rib 23. The modeling scope was defined as the area enclosed by the dashed line in Figure 11.

[0048] Furthermore, the parameters listed below were common to all models. Deck plate thickness: 0.8mm Deck plate height DPh: 90mm The deck plate height DPh is the vertical distance from the horizontal surface 2 (top surface) of the deck plate 1 to the bottom surface of the reinforcing rib 3. Support span: 4,000 mm Material: SDP2G (Refer to JIS G 3352 deck plate)

[0049] Figure 12 illustrates the intra-sectional deformation δ in the deck plate model. As shown in Figure 12, the FEM analysis assumes that the center of the horizontal section 2 of the deck plate 1 is supported by a tight frame 70. Due to the center of the horizontal section 2 being supported by the tight frame 70, deformation occurs on the side of the reinforcing rib 3. The intra-sectional deformation δ is the amount of vertical deformation of the reinforcing rib 3.

[0050] Figure 13 is a graph showing the relationship between the amount of deformation δ within the cross-section of deck plate 1 and the heating time. As mentioned above, in the FEM analysis, the temperature rise of deck plate 1 is applied linearly so that the temperature after 30 minutes (1800 seconds) fits the ISO standard heating curve. As shown in the graph in Figure 13, in the first half, the amount of deformation δ within the cross section decreases as the height of the unevenness increases, but this reverses in part around 1300 seconds from the start of heating, indicating that the deformation performance plateaus with the model having an unevenness height of 4 mm. Table 1 shows the amount of deformation δ within the cross section at 1520 seconds (approximately 25 minutes) from the start of heating.

[0051] [Table 1]

[0052] Furthermore, Table 2 shows the results of varying the deck plate (DP) height and deck plate thickness, and organizing the data in the same way as in Table 1.

[0053] [Table 2]

[0054] The values ​​obtained by dividing the δ for the uneven specification (listed in the far right column) by the δ for the smooth specification are all less than 1, confirming that even when the deck plate height or thickness is changed, there is an effect of suppressing the amount of deformation within the cross-section by about 20-40%. Therefore, by providing unevenness (mountain-shaped ribs), the amount of deformation δ within the cross-section can be reduced, and the clearance c can be increased. Specifically, when the unevenness is 4 mm or more, the maximum amount of deformation within the cross-section is 26.2 mm (from the results of Model 3-3), so by setting the clearance c to 26.2 mm or less, the disengagement of the deck plates can be suppressed. On the other hand, the minimum value of the internal deformation δ was 5.93 mm (from the results of Model 3-5), indicating that even when the height of the unevenness is increased and the deck plate thickness is maximized, a deformation of 5.93 mm occurs. Therefore, keeping the clearance c at 5.93 mm or less is a necessary condition for suppressing the disengagement of the deck plates.

[0055] In the above analysis, the spacing between the reinforcing ribs and the fitting ribs in the width direction was assumed to be 200 mm in all cases. However, the amount of deformation δ within the cross-section increases as the spacing increases. While spacing between reinforcing ribs and fitting ribs of 200 mm or less is not problematic, if it exceeds 200 mm, it is desirable to limit the increase to about 10% (220 mm) or to adopt it after conducting special considerations. Special considerations could include, for example, modeling the shape of the deck plate to be used, as in the analysis described above, and calculating the intra-sectional deformation δ by inputting load and heat quantities based on the "Fire Resistance Performance Confirmation Test and Evaluation Procedure Manual," or measuring the intra-sectional deformation δ in a full-scale test. The intra-sectional deformation δ obtained by these methods may be used instead of the intra-sectional deformation δ obtained by the FEM analysis described above.

[0056] According to the above embodiment, in a deck roof structure 100 in which deck plates 1 are fitted together, even if the deck plates 1 are deformed due to a temperature rise caused by a fire or the like, it is possible to prevent the deck plates 1 from coming apart.

[0057] Furthermore, when a V-shaped rib 23 is provided in the horizontal section 2, the amount of deformation δ within the cross-section can be reduced and the clearance c can be increased by setting the height of the V-shaped rib 23 to 4.0 mm or more and 12 mm or less.

[0058] Similarly, by setting the widthwise spacing between the reinforcing rib 3 and the fitting ribs 4 and 5 to 200 mm or more and 220 mm or less, the thickness of the deck plate 1 to 0.8 mm or more and 1.6 mm or less, and the height of the deck plate 1 to 75 mm or more and 120 mm or less, the amount of deformation δ within the cross-section can be reduced and the clearance c can be increased.

[0059] Furthermore, the method of fitting adjacent deck plates 1 together is not limited to the fitting ribs of the shape described above. For example, it is also possible to use fitting ribs 3A and 35 of the type in which the deck plates 1 together are fitted together by inserting the right-angle bent portion 35 into the closing portion 30 as shown in Figure 14.

[0060] The fitting ribs 3A and 35 are configured such that a right-angle bent portion 35, provided on the other edge of the horizontal portion 2, is inserted into a reinforcing rib 3A provided on one edge of the horizontal portion 2. The reinforcing rib 3A on one edge in the width direction of the deck plate functions as an insertable reinforcing rib 3A into which the right-angle bent portion 35 is inserted.

[0061] For joining the deck plates 1 together, it is sufficient to simply insert the right-angle bent portion 35 into the closing portion 30 and fit them together. Alternatively, measures to increase resistance to disengagement, as shown in Figure 9, may be taken, such as joining with self-drilling screws if necessary. [Explanation of symbols]

[0062] 100... Deck roof structure, 1... Deck plate, 2... Horizontal section, 21... First horizontal section, 22... Second horizontal section, 23... V-shaped rib, 24... Mountain-shaped section, 25... Flat plate section, 26... Slanted side, 3... Reinforcement rib, 30... Closing section, 31... Reinforcement rib section, 35... Right-angle bend section, 3A... Reinforcement rib, 4... First fitting rib, 40... First web section, 41... Inclined section, 42... First flange section, 43... First folded section, 44... Guide inclined section, 5... Second fitting rib, 50... Second web section, 51... Second flange section, 52... Pressing inclined section, 70... Tight frame, 71... Convex section, 72... Base section, 73... Support surface section, 74... Inclined section, 90... Main body, 91... Flange, 92... Web.

Claims

1. A deck plate comprising a horizontal section and a pair of left and right fitting ribs formed on both sides of the horizontal section in the width direction, It comprises a base portion and a tight frame on which the deck plate is laid, having a plurality of protrusions that protrude from the base portion and contact the lower surface of the horizontal portion, A deck roof structure characterized in that the clearance c between the lower end of the fitting rib and the upper surface of the base portion of the tight frame is 5.93 mm or less.

2. The deck roof structure according to claim 1, characterized in that δ is the amount of deformation within the cross-section of the deck plate, and c is the clearance between the lower end of the fitting rib and the upper surface of the base portion of the tight frame, wherein δ > c.

3. The deck plate has a plurality of V-shaped ribs formed in the horizontal portion and extending in the longitudinal direction, The deck roof structure according to claim 1 or claim 2, characterized in that the height of the V-shaped rib is 4.0 mm or more and 12 mm or less.

4. The deck plate has reinforcing ribs formed in the horizontal portion and extending in the longitudinal direction, The deck roof structure according to claim 1 or claim 2, characterized in that the distance in the width direction between the reinforcing rib and the fitting rib of the deck plate is 200 mm or more and 220 mm or less.

5. The deck roof structure according to claim 1 or claim 2, characterized in that the thickness of the deck plate is 0.8 mm or more and 1.6 mm or less.

6. The deck roof structure according to claim 1 or claim 2, characterized in that the height of the deck plate is 75 mm or more and 120 mm or less.

7. A deck plate having a horizontal section and a pair of left and right fitting ribs formed on both edges of the horizontal section in the width direction, A method for designing a deck roof structure comprising a base portion and a tight frame having a plurality of protrusions that project from the base portion and contact the lower surface of the horizontal portion, on which the deck plate is laid, A method for designing a deck roof structure, characterized in that, if the amount of deformation within the cross-section of the deck plate is δ and the clearance between the lower end of the fitting rib and the upper surface of the base portion of the tight frame is c, then the structure is designed such that δ > c.

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