Composite structure

Abstract

To provide composite construction that can be used at a portion affecting large shear force without placing a plurality of joint members and enables improvement specially in terms of joint member production and a welding amount.SOLUTION: Composite construction 1 includes a steel member 10 on which joint members 30 are provided and a concrete-based member in which the joint members 30 are embedded. The joint member 30 has a tabular flat plate part 31, an open hole 32 provided at the flat plate part 31, and a protrusion part 36 provided on the flat plate part 31 and protruding in the direction perpendicular to a surface of the flat plate part 31. A plurality of joint members 30 is placed in a longer direction of the steel member 10. A distance between centers of open holes 32 of joint members 30 adjacent to each other is more than or equal to a first specified value PV1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a composite structure formed by integrally joining a steel member and a concrete-based member when constructing a building structure, a civil engineering structure, or the like.

Background Art

[0002] A structure formed by integrally joining a steel member and a concrete-based member (hereinafter referred to as "composite structure" in this specification) is widely used in the fields of building structures, civil engineering structures, and the like. In order to achieve reliable and smooth stress transmission between such dissimilar materials at the joint between these steel members and concrete-based members, a resistance action by anti-slip is essential. Based on this point, conventionally, for example, in the portion where a steel beam and a concrete slab are joined, a structure in which the concrete slab is joined to the steel beam via studs welded to the upper surface of the steel beam flange has been used (see, for example, Patent Documents 1, 2, etc.).

[0003] In such a composite structure in which a steel beam and a concrete slab are joined, since the studs transmit shear forces while deforming themselves, a large number of studs are required to realize a state in which both are well joined. For this reason, a large arrangement space is often required to arrange the studs.

[0004] Conventionally, as a joining member capable of solving such problems, a strip-shaped perforated steel plate shear connector (hereinafter referred to as a steel plate provided with through holes in this specification) in which a plurality of through holes are provided at predetermined intervals has been used (see, for example, Patent Documents 3, 4, etc.).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the perforated steel plate shear key as described above has a high effect of suppressing displacement deformation (here, the relative displacement between the slab and the steel frame), but since the shear strength is small, a large number of them have to be arranged when used in a place where a large shear force acts.

[0007] Also, as in Patent Document 4, a technique using a joining member having a shape in which a plurality of through holes are formed in a long rectangular steel plate has been proposed, but such a joining member is considered to still have room for improvement in terms of manufacturing and the amount of welding.

[0008] Therefore, an object of the present invention is to provide a composite structure that can be used in a place where a large shear force acts without arranging a large number of joining members, and that can be improved especially in terms of the attachment of the joining members and the amount of welding.

Means for Solving the Problems

[0009] One aspect of the present invention is a composite structure including a steel member provided with a joining member and a concrete member in which the joining member is embedded, The joining member has a plate-shaped flat plate portion, a through hole provided in the flat plate portion, and a protrusion protruding in a direction perpendicular to the surface of the flat plate portion provided in the flat plate portion. A plurality of joining members are arranged along the longitudinal direction of the steel member, It is a composite structure in which the distance between the centers of the through holes of adjacent joining members is equal to or greater than a first predetermined value.

[0010] According to the composite structure of the above-described aspect, by using a joining member having a through hole and a protrusion and being excellent in suppressing displacement deformation and transmitting shear force, a composite structure (in this specification, used as a term meaning a structure in which a steel member (steel frame beam) and a concrete member (concrete slab) are integrated to resist) is formed, and while improving the structural performance (used as a term meaning rigidity and load-bearing capacity in this specification), the number of joining members can be reduced. Reducing the number of joining members leads to a decrease in the placement locations, a decrease in obstacles at the work site, and a decrease in the amount of welding. Moreover, since a composite structure can be realized with fewer joining members, compared with a steel frame beam of equivalent performance, the amount of steel material can be reduced, such as by reducing the beam cross-section, which is economical.

[0011] Further, the composite structure of the above-described aspect enables an arrangement that can effectively transmit shear force. That is, when increasing the resistance to displacement deformation (shear strength between members) between the steel member and the concrete member, it is desired to arrange a large number of joining members. However, if they are arranged with a reduced interval, there is a risk that the steel plate will not deform and concrete failure will occur first. On the other hand, the composite structure with the reduced number of joining members as described above can transmit shear force while avoiding the occurrence of concrete failure first.

[0012] In the composite structure of the above-described aspect, the distance from the longitudinal end of the concrete member to the end of the joining member closest thereto may be equal to or greater than a second predetermined value.

[0013] In the composite structure of the above-described aspect, the concrete cover thickness representing the thickness between the upper end of the flat plate portion of the joining member of the composite structure disposed and in use in the structure and the upper end of the concrete member may be equal to or greater than a third predetermined value.

[0014] In the composite structure of the above-described aspect, the distance from the surface of the steel member to which the joining member is joined of the composite structure disposed and in use in the structure to the upper end of the concrete member may be equal to or greater than a fourth predetermined value.

[0015] In the composite structure of the above-described aspect, when the composite structure is disposed in a structure and is in a use state, the protrusion of the joining member protrudes facing one side, and on the side where the protrusion does not protrude, the distance from the center of the plate thickness of the flat plate portion of the joining member to the concrete edge may be equal to or greater than a fifth predetermined value.

[0016] In the composite structure of the above-described aspect, when the composite structure is disposed in a structure and is in a use state, the protrusion of the joining member protrudes facing one side, and on the side where the protrusion protrudes, the distance from the center of the plate thickness of the flat plate portion of the joining member to the concrete edge may be equal to or greater than a sixth predetermined value.

[0017] In the composite structure of the above-described aspect, when the composite structure is disposed in a structure and is in a use state, a concrete raising member is installed so as to sandwich the flat plate portion of the joining member, and the distances from the center of the plate thickness of the flat plate portion of the joining member to the respective concrete raising members (when in the use state as shown in FIG. 15, when the raising member is gently raised from the edge of the steel member, the distance to the average position of the height) may be equal to or greater than a seventh predetermined value.

[0018] In the composite structure of the above-described aspect, the raising amount of the concrete raising member may be 50 mm or less.

[0019] In the composite structure of the above-described aspect, one through hole may be provided in the flat plate portion, and a protrusion may be provided at the periphery of the through hole.

[0020] In the composite structure of the above-described aspect, the joining members may be a pair and may be arranged in parallel along the longitudinal direction of the steel member.

[0021] In the composite structure of the above-described aspect, the distance between the centers of the plate thicknesses of the flat plate-like base materials of the pair of joining members may be equal to or greater than an eighth predetermined value.

[0022] In the composite structure of the above-described aspect, the respective protrusions of the pair of joining members may face inward.

Advantages of the Invention

[0023] According to the present invention, it is possible to provide a composite structure that can be used at a location where a large shearing force acts without arranging a large number of joining members, and moreover, it is possible to improve aspects such as the attachment of the joining members and the amount of welding.

Brief Description of the Drawings

[0024]

Figure 1

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Embodiments for Carrying Out the Invention

[0025] Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings (see FIG. 1 etc.).

[0026] [Overview of Joint Member and Reinforcement Structure] The composite structure (hereinafter also referred to as "reinforcement structure") 100 is a structure formed by integrally joining a steel member 10 and a concrete-based member 20 (see FIG. 1), and is widely used in fields such as building structures and civil engineering structures. The steel member 10 is used, for example, as a steel frame beam in a building (hereinafter sometimes simply referred to as "beam". In FIGS. 3 etc., only a part of the steel member 10 is shown in the figure). As an example, the steel member 10 of the present embodiment has a long side 10X extending in the horizontal direction in FIG. 1 and a short side 10Y extending in the vertical direction in FIG. 1. The concrete-based member (for example, slab) 20 is used as a member constituting the framework (columns, walls, etc.) of the structure. The joint member 30 is used as a member for joining the steel member 10 and the concrete-based member 20.

[0027] The joint member (sometimes referred to as "barring shear connector" in this specification) 30 is a member for joining the steel member 10 and the concrete-based member 20, and constitutes the reinforcement structure 100 by joining the two (see FIGS. 1 to 3). In this reinforcement structure 100, there is a partition of a steel plate (flat base material) 31 shapeA flat joining member 30 installed at [the relevant position] with one side surface 31f and the back surface (not shown) joined by fillet welding 32, and a concrete-based member 20 formed on the surface 31f of the steel plate 31 with the joining member 30 embedded therein are included. A plurality of joining members 30 are arranged along the direction of the long side 10X of the steel member 10 (see Fig. 1). Through holes 35 are provided in these joining members 30. At the edge of the through hole 35, a protruding edge portion 36 is provided so as to protrude upward from one surface 31f of the joining member 30 (see Fig. 2). The through hole 35 is, for example, circular, and the protruding edge portion 36 has a boss-like or circumferential shape such as a sleeve shape continuous in the circumferential direction along the inner peripheral edge of the through hole 35. The protruding height of the protruding edge portion 36 from the surface 31f of the steel plate 31 is uniform in this embodiment (see Fig. 2, etc.), but conversely, the height may be intentionally made non-uniform. In this embodiment, the steel plate 31 forms a flat base material, but the material and material quality are not limited to this. In addition, although not particularly shown, those obtained by burring a steel pipe or those obtained by burring a section steel may be adopted.

[0028] In the reinforcement structure 100, the displacement between the joining member 30 and the concrete-based member 20 is prevented by the shear resistance of the concrete-based member 20 filled in the through hole 35 and the concrete-based member 20 around it (see Fig. 3, Fig. 16, etc.). Further, the protruding edge portion 36 provided in the through hole 35, the concrete-based member 20 in the vicinity thereof, and the end face 31A in the longitudinal direction of the steel plate 31 and the concrete-based member 20 exhibit a displacement prevention function by bearing pressure resistance, so the rigidity is high and the shear strength is greatly improved. In addition, the fillet welding 32 for joining the joining member 30 to the surface 31f of the steel plate 31 can be carried out in a factory or the like in advance and then transported to the construction site. By doing so, it is possible to avoid welding work at the construction site, and the workability is good. Note that the fillet welding 32 may be such that two long sides are welded as shown in Fig. 3, etc., or may be welded so as to go around including the end face 31A, and the shape of the fillet welding is not limited to that shown in the figure.

[0029] In addition, by providing the protruding edge portion 36 in the through hole 35, the rigidity of the joining member 30 itself is increased and it becomes difficult to deform. Therefore, the handleability during transportation and storage is improved, which is effective for improving the workability and contributes to the improvement of the strength of the reinforcing structure 100. Further, by improving the rigidity of the joining member 30, it is possible to prevent deformation due to the heat influence when performing the fillet welding 32.

[0030] Incidentally, the through hole 35 formed in the joining member 30 can also be used as an insertion hole for a wire rope, a shackle, etc. when lifting the steel material to which the joining member 30 is joined with a crane. Further, since a reinforcing bar can be inserted into the through hole 35 of the joining member 30, it can also be used as a spacer for holding the position and height of the reinforcing bar when performing the reinforcing bar placing work at the construction site of a building or civil engineering structure.

[0031] The processing method for forming the protruding edge portion 36 of the through hole 35 is not particularly limited, but in this embodiment, it is formed by a flanging process. The flanging process is a processing technique for raising the inner peripheral edge of the pre-hole formed in the steel plate 31, which is the material of the joining member 30, in the plate thickness direction of the steel plate 31 using a punch and a die.

[0032] Note that the steel member 10 constituting the reinforcing structure 100 is not limited to an H-shaped steel steel girder as long as it is a material to which the joining member 30 can be joined. For example, any shape steel such as an I-shaped steel, a T-shaped steel, an angle steel, a channel steel, or a steel pipe may be used for the beam.

[0033] Note that since a reinforcing bar (not shown) can be inserted into the through hole 35 of the joint member 30, one or a plurality of reinforcing bars (not shown) can be inserted into each through hole 35, and a structure can be adopted in which the concrete-based member 20 is formed on the surface 31f of the steel plate 31 with the joint member 30 and the reinforcing bars (not shown) embedded. With such a structure, the shear force (referring to the shear force in the direction parallel to the surface 31f of the steel plate 31, represented by the reference sign F in the figure. Also, the direction in which the shear force F acts (the horizontal direction in the case of this embodiment) is referred to as the shear force acting direction and represented by the reference sign X) can be shared by the reinforcing bars, so that the deformation capacity is improved, and excellent effects such as an improvement in the resistance to the lifting of the concrete-based member 20 can be obtained.

[0034] [Joint member with improved "displacement deformation performance"] In the joining member 30 that joins the steel member 10 and the concrete member 20 as described above, in order to achieve reliable and smooth stress transmission between these different materials, it is important to maintain a state in which the resistance due to displacement prevention acts. When an external force acts (see Fig. 1), it is normally possible for the concrete member 20 to break before the joining member 30 deforms or breaks. However, in light of the above point (the point that it is important to maintain a state in which the resistance due to displacement prevention acts), at the moment the concrete member 20 breaks, the state in which the resistance due to displacement prevention acts must inevitably be interrupted. Even if the concrete member does not completely break, the displacement prevention such as studs commonly used generally resists the force of the concrete trying to displace with a bearing pressure, and it is known that the bearing capacity deteriorates when the force acts repeatedly due to the bearing deformation of the concrete. Considering this point, in the embodiment, when a stress is generated in both the concrete member 20 and the steel member 10 by the action of an external force (see Fig. 1), the joining member 30 is formed in a shape that breaks prior to the concrete member 20. By incorporating the idea of causing the joining member 30 to break prior to the concrete member 20, it becomes possible to design by focusing on the cross-section of the joining member 30. Also, by making the shape and structure of the joining member 30 itself such that it deforms sufficiently, brittle fracture can be prevented, and it becomes possible to improve the deformation performance of the displacement prevention (the function or performance of suppressing the relative displacement accompanying displacement).

[0035] In determining the shape and structure of the joining member 30, by being determined by the shear strength rather than the bending strength within the steel plate surface, the shear force transmission capacity of the steel plate 31 can be fully exerted. For example, if the steel plate 31 is a single long rectangular plate in the shape of a single sheet long in the shear force acting direction X, and the joining member 30 is a single plate made of the steel plate 31 (see Fig. 9(A)), the shear strength of the joining member 30 during the action of the shear force F is mainly dominated by the shear strength (shear stress) of the steel plate 31 (the shear force of the steel plate 31 is prominent with respect to the displacement direction force, and bending failure does not occur. In the present embodiment, by arranging a plurality of joining members 30 in a discontinuous state, so to speak, a structure is constructed in which the bending strength rather than the shear strength is dominant (see Fig. 9(B)). However, for an object with a long height (h) like this, the bending stress of the steel plate 31 is prominent with respect to the shear force acting direction X (displacement direction), and shear failure does not occur. In this regard, in the present embodiment, attention is paid to the restraining function of the concrete-based member 20 to cause shear failure. This will be described later.

[0036] [Features of the reinforcement structure (1): High shear transmission performance by discontinuously arranged joining members] As described above, in the reinforcement structure 100 of the present embodiment, a plurality of joining members 30 having a shape with one through-hole 35 per steel plate 31 are arranged intermittently and discontinuously, rather than continuously. Such a structure, compared to a structure where they are continuously connected (i.e., a continuously connected structure), adds the bearing resistance of the edge surface (referring to the surface of the side of the steel plate 31 where the shear force F acts, indicated by reference numeral 31A in the figure) of each steel plate 31 and the bearing resistance of the flange portion 36 (the resistance corresponding to the shear force acting on the attachment portion of the flange portion 36 (indicated by reference numeral 36A in FIG. 5)), thereby improving the shear transmission performance (the performance of transmitting the force acting in the shear direction) of the entire steel plate 31. This can be more easily understood by assuming that when the steel plate 31 is, for example, a single rectangular plate long in the shear force acting direction X, the number of edges is small (for example, in the case of such a single steel plate 31, there is one edge), and the added shear force F acting on the edge is small. In FIGS. 5 to 7, after indicating the forces acting on the edge surface 31A and the attachment portion 36A with arrows (force diagrams), they are denoted as "bearing resistance".

[0037] According to the reinforcement structure 100 of the present embodiment with improved shear transmission performance as described above, by providing the through-holes 35 one-to-one with respect to the flange portions 36 (one through-hole 35 for one flange portion 36), the increased allowable stress of the attachment portion 36A of the flange portion 36 can be considered. Therefore, the shear strength per unit can be increased and the number of members can be reduced compared to the prior art. Also, the workability (ease of work) is improved by the amount of reduction in the number of joining members 30 and the miniaturization of each member. Further, according to the reinforcement structure 100 of the present embodiment, the amount of welding is reduced and the ease of construction is improved. Also, in the case of the structure where one through-hole 35 is formed per steel plate 31 as in the present embodiment, the force acting on the concrete member 20 can be dispersed and received by the edge surface 31A and the peripheral surface (the projection surface) of the flange portion 36, that is, the attachment portion 36A. Therefore, it is easy to ensure the overall strength and it is easy to improve the performance accordingly.

[0038] Next, to give a specific example of achieving the above-described high shear transmission performance, an example of a preferable range of the width B of the steel plate 31 of the joining member 30 (here, the width means the length along the shear force acting direction X (see FIG. 6 etc.)) is about 1.6 to 3 times the hole diameter of the through-hole 35. If specific numerical examples are given, it is 80 to 150 [mm] per one through-hole 35 and the flange portion 36. Explaining in another expression, when a steel plate 31 with a width B within the range of 80 to 150 [mm] is adopted with respect to the diameter φ40 to 60 [mm] of the through-hole 35, it becomes easy to form a configuration in which the through-hole 35 and the flange portion 36 are positioned at a predetermined preferable interval along the shear force acting direction X, which is preferable. Incidentally, when the width B is shorter than a predetermined value (80 [mm] in this example), the shear force transmission ability of the entire joining member 30 becomes small, so it is necessary to arrange a larger number of joining members 30 to ensure a shear force transmission ability equal to or greater than a predetermined value (if the steel plate width B is less than 80 mm, the shear strength determined by the fracture of the steel plate 31 is out of the practical range, and the shear strength per one becomes small. For this reason, in order to obtain the necessary joining strength between the concrete-based member 20 and the steel member 10, a large number of anti-slip measures are required). However, when a large number of joining members 30 are arranged excessively, the interval becomes small and the shear strength of the concrete-based member 20 cannot be ensured, so that "the shear strength of the steel plate 31" < "the shear strength of the concrete-based member 20" does not hold. On the other hand, when the width B is longer than a predetermined value (150 [mm] in this example), although the shear strength of the steel plate 31 increases, the concrete-based member 20 (for example, a slab. Hereinafter, it may be simply referred to as "slab") is in a state of being cut off by the joining member 30 so to speak, and the concrete-based member 20 held by these joining members 30 is likely to be damaged, and the deformation ability of the steel plate 31 itself becomes poor and the damage of the concrete-based member 20 tends to occur first. Furthermore, when the width B of the joining member 30 is longer than a predetermined value (150 [mm] in this example), it tends to be relatively expensive due to an increase in materials and work due to an increase in the welded portion between the steel member 10 and the joining member 30 and an increase in the size of the steel plate 31.

[0039] In the above description of the width B of the steel plate 31, it was described as "around one through-hole 35 and the flange portion 36". This is because by providing a plurality of flange portions 36 temporarily (it may be provided only on one surface side of the steel plate 31, or on both surfaces respectively), the shear strength of the concrete member 20 increases. Therefore, the width B of the steel plate 31 can be increased accordingly to prevent displacement and increase the overall shear strength. However, here too, the shear strength of the concrete member 20 must exceed the shear strength of the steel plate 31. When there is only one small opening, it is not simply a multiple of the number, but by increasing the flange portion 36, the resistance of the concrete can be increased, so the length of the steel plate 31 can be increased. As the length of the steel plate 31 increases, the shear strength of the steel plate can be increased.

[0040] Also, in the reinforcement structure 100 of the present embodiment, adjacent joining members 30 are arranged such that the distance between the centers of their through-holes 35 is equal to or greater than a first predetermined value PV1 (see FIG. 1). As a preferred example, the predetermined value PV1 is 180 mm. When the installation interval of the steel plates 31 of the joining members 30 (PV1 in this embodiment) is smaller than the slab thickness (that is, the thickness of the concrete member 20, indicated by the symbol G in FIG. 11. As an example, the slab thickness G is 150 mm), it is evaluated that the bearing area Ac becomes smaller. When the bearing area Ac becomes smaller, the concrete bearing strength fb one line below Equation [5] described later becomes smaller, and the shear strength due to the bearing resistance of Equation [5] becomes smaller. On the other hand, if the interval becomes larger, the bearing area Ac becomes larger isAs a result, the bearing pressure strength fb increases, and the concrete bearing capacity in Equation [5] increases. According to such a reinforcement structure 100, a structure for joining a steel member (such as a steel beam) 10 and a concrete member (such as a concrete slab) 20 with a smaller number of joining members 30 than before can be formed. Further, according to this reinforcement structure 100, both the steel member 10 and the concrete member 20 can be joined in a better state by the plurality of joining members 30. Further, according to such a reinforcement structure 100, the workability (such as the workability at the construction site) is improved. Further, according to such a reinforcement structure 100, by using the joining member 30 excellent in shear force transmission, the relative displacement between the steel member and the concrete member is suppressed and a composite structure (a structure in which a steel beam and a concrete slab are integrated to resist) is formed to improve the structural performance (rigidity, bearing capacity), while the number of the joining members 30 can be reduced. Reducing the number of the joining members 30 leads to a reduction in the placement locations, a reduction in the obstacles at the work site, a reduction in the welding amount, etc., which improves the workability. In addition, by forming a composite structure beam, the amount of steel can be reduced compared with a steel beam having the same performance.

[0041] [Feature of the reinforcement structure (2): Suppressing steel plate bending with concrete that restrains the upper part of the steel plate] In the present embodiment, a reinforcement structure 100 is constructed in a state where the upper part of the steel plate 31 (for example, all parts above the fillet weld 32 part) is covered and restrained by the concrete member 20 (in other words, in a state where the steel plate 31 that tries to bend is pressed from above so as not to be bent).

[0042] Here, the restraint function will be described with reference to the drawings (see FIGS. 7 and 8). When a force that causes relative displacement due to displacement occurs in the steel member 10 or the concrete member 20, the steel plate 31 that is not restrained by the concrete member 20 tends to be bent in the plane. (See FIGS. 7(A) and 8(A)). In this case, since the stress due to in-plane bending is prominent in the steel plate 31, the steel plate 31 is likely to undergo bending failure at an early stage. On the other hand, when a force that causes relative displacement due to displacement occurs in the steel plate 31 restrained by the concrete member 20, the in-plane bending of the steel plate 31 is restrained by the concrete member 20, and the steel plate 31 is in a state of being pressed down from above, so the bending stress at the root position (cross-section 31d) of the steel plate 31 is suppressed (see FIG. 7(B)). Therefore, until the steel plate 31 is broken by the shear stress at the root position of the steel plate, the failure due to the bending stress is suppressed.

[0043] (Without considering the restraint force) In order to shear-deform the steel plate 31, the width B must be increased. However, as the width B of the steel plate 31 is increased, problems such as increased material cost and increased welding become apparent when the steel plate 31 is long and continuous, and the concrete member 20 will break before the steel plate 31. In other words, it can be said that the reinforcement structure 100 of the present embodiment as described above is a structure in which the concrete member 20 arranged on the upper side restrains the bending deformation of the steel plate 31, so that the shear strength of the steel plate 31 can be maintained until the limit is reached while the width B of the steel plate 31 remains small.

[0044] From the perspective of fully exerting the above-mentioned restraint function, the covering thickness of the concrete member (the distance representing the thickness from the end face of the steel plate 31 (however, the end face of the upper end part on the side opposite to the steel member 10) 31B to the top end (upper end) 21 of the concrete member 20) C is not less than a third predetermined value PV3. For example, specifically, it is preferably at least 30 mm or more, more preferably 50 mm or more. In the case of a concrete slab or the like, although it is desired to reduce the slab thickness G and the covering thickness PV3 to reduce the weight, if the restraint force on the upper part of the steel plate 31 is small, fracture due to bending stress will occur first at the root position (cross section 31d) of the steel plate 31, resulting in a concern that the shear transfer capacity will decrease. To prevent this, by restraining the upper part of the steel plate 31 with the concrete member 20 by PV3 or more, the performance can be exerted up to the shear strength of the steel plate 31, and the overall shear force transfer capacity is improved.

[0045] [Features of the Reinforcement Structure (3): Shape in which the Joining Member Fails before the Concrete Member] As described above, based on the idea that the joining member 30 of the reinforcement structure 100 of the present embodiment fails before the concrete member 20, (Shear Strength of Steel Plate) < (Strength of Concrete Member) it is formed into a shape that satisfies this. However, specific examples of the shape of the joining member 30 are not particularly limited. In short, it can be said that the fact that the joining member 30 has such a shape itself is a feature of the joining member 30 of the present embodiment and the reinforcement structure 100 including the same. Specific examples of the concept and the shape / structure examples embodied thereby are as follows.

[0046] When considering the projected area of the steel plate 31 (including the flange part 36) along the shear force acting direction X (see Fig. 5. In this specification, it is referred to as the visible area and represented by the symbol A. Note that in Fig. 5(B), hatching is added for easy understanding, but it should be noted that this does not represent a cross section) and the cross-sectional area D of the cross section 31d of the steel plate 31 that is considered to receive the largest shear action (see Fig. 4), the ratio of these, that is, the visible area A / the cross-sectional area D of the steel plate, is The ratio of the visible attachment area A to the cross-sectional area D of the steel plate is 1.20 to 3.45 It is preferable that the ratio is within the range in order for the joining member 30 to break before the concrete member 20. The joining member 30 having a ratio value of about 2.55 can be said to be more preferable from this viewpoint.

[0047] As described above, the joining member 30 of the present embodiment sets the ratio of the cross-sectional area D along the acting direction of the shear force F acting on the joining member 30 and the visible attachment area A along the acting direction X of the shear force of the joining member 30 within a predetermined range. As described so far, by making the shear strength of the joining member 30 (the steel plate 31 thereof) < the strength of the concrete member, it is possible to design the joining member 30 that can deform while maintaining the shear strength even after the steel plate 31 yields, using the cross-sectional area D of the steel plate 31 as a parameter. Of course, the flange portion 36 as in the present embodiment formed on the joining member 30 protrudes in a direction to increase the visible attachment area A and affects the design based on the above formula.

[0048] [Features of the reinforcement structure (4): Shear strength of the joining member] The shear strength of the joining member (barring shear connector) 30 of the reinforcing member 100 will be described (see FIGS. 5, 6, etc.). The shear strength of the concrete member is obtained by adding the bearing resistance due to the visible attachment area consisting of the flange portion 36 and the end face and the shear resistance between the concrete filled in the through hole and the surrounding concrete.

[0049] The preconditions for obtaining the shear strength of the barring shear connector are shown below. Needless to say, the specific numerical values shown below are only a preferred example. (1) The concrete cover on the upper surface of the barring shear connector (the cover thickness of the concrete member 20) C is 30 mm or more (see FIG. 6). (2) The slab thickness G (the thickness of the concrete member 20) at the location where the barring shear connector is arranged shall be not less than a fourth predetermined value PV4 from the upper surface of the steel member (specifically, a beam flange as shown in FIG. 11, etc.) 10. For example, it shall be not less than 150 mm (see FIG. 11). From formulas (refer to formula [6] described later), etc., it can be said that "when the slab thickness G is small → the bearing area is small → the concrete bearing capacity decreases". In this embodiment, in consideration of this, the slab thickness G is set to be not less than the predetermined value PV4. (3) The distance J from the slab end (the longitudinal end of the concrete member 20) to the front small opening surface 31A in the shear force acting direction X (in this embodiment, equal to the longitudinal direction of the concrete member 20) of the barring shear connector closest to the slab end shall be not less than a second predetermined value PV2 (for example, not less than 250 mm) (see FIG. 10). By doing so, the small opening surface 31A and the protruding edge 36 of the joining member 30 press against the surrounding concrete, which leads to ensuring the shear force transmission capacity of the barring shear connector by preventing the destruction that would cause the end of the concrete member 20 to be punched out. (4) Although it is known that the steel bars in the slab also contribute to the restraint force of the concrete member, it is difficult to clearly evaluate the restraint effect and design accordingly. Also in this embodiment, as a prerequisite, the naturally configured slab shall contain an amount of steel bars that complies with various design standards. (5) When the distance K from the center of the plate thickness of the flat plate portion (indicated by reference numeral 37 in Fig. 12(A)) of the flat steel plate 31 of the barring shear connector to the edge of the floor slab (concrete member 20) is such that the protruding edge portion 36 faces the outside of the concrete member 20, the barring shear connector is arranged so that it is not less than a sixth predetermined value PV6, for example, not less than 200 mm (see Fig. 12(A)). When the barring shear connector is arranged so that the protruding edge portion 36 faces the inside of the concrete member 20, it is not less than a fifth predetermined value PV5, for example, not less than 100 mm (see Fig. 12(B)). Since the bearing pressure generated in the protruding edge portion 36 is transmitted to the concrete member as shown in Fig. 17, if there is not enough concrete on the protruding edge portion 36 side, a sufficient bearing area cannot be ensured and the concrete bearing capacity decreases (see Equation [6] etc. described later). In this embodiment, by setting the distance K to be not less than a predetermined value as described above, the concrete bearing capacity is prevented from decreasing. (6) When arranging the barring shear connectors in parallel on the beam flange (steel member 10), the number shall be up to a set of two (see Fig. 13). In this case, the distance L between a set of barring shear connectors shall be not less than 100 mm, which is the distance between the centers of the plate thicknesses of the flat steel plates 31 (see Figs. 13(A) and 13(B)). However, the orientation of the respective protruding edge portions 36 of the barring shear connectors arranged in parallel is not limited to that shown in Fig. 13. (7) On the upper surface of the steel member 10, a deck plate (concrete raising material) 300 is installed so as to sandwich the flat plate portion of the joining member 30. When there is a raise (referred to as slab raise) on the beam (steel member 10) by the deck plate 300, the raise amount (the peak height of the deck plate 300) N shall be below a predetermined value, for example, 50 mm or less (see Fig. 14). This is one of the conditions specific to the joining member 30 of this embodiment. When the height from the steel plate 31 at the center of the through hole 35 is 50 mm, if the raise amount exceeds 50 mm, the area caught by the protruding edge portion 36 and the shear cross-section of the raised portion becomes insufficient, and it was confirmed that the range where shear failure does not occur is 50 mm or less because it will break at the shear cross-section of the raised portion. In this case, ensure a raise width of 200 mm or more (100 mm or more from the center of the plate thickness of the steel plate 31 of the barring shear connector) so as to be uniform from the center in the beam flange width direction. Also, when using a deck plate 300 that has been subjected to end closure processing (processing in which the end of the deck plate with unevenness is flattened so that concrete does not leak from the peak portion, as described in, for example, JP-A-2005-290671), use the average of the slab widths at the lower and upper ends of the raise as the effective slab width, and ensure an effective width of a predetermined value, for example, 200 mm or more (from the center of the plate thickness of the flat plate portion of the barring shear connector, each of the seventh predetermined value PV7 or more, for example, 100 mm or more) uniformly from the center in the beam flange width direction (see Fig. 15). Generally, when the width becomes narrow, shear failure occurs and cracks at the interface between the raised portion of the concrete member and the slab. Therefore, in this embodiment, the above is done to avoid this.

[0050] The shear strength of the barring shear connector is represented by the smaller of the shear strength of the steel plate 31 and the shear strength due to the concrete resistance, and is expressed by Equation [1]. Regarding the shear strength of the steel plate 31, the cross-sectional area D (see Fig. 4) of the cross-section 31d of the steel plate 31, which is considered to receive the largest shear action, is taken as the design cross-section.

Equation

[0051] The concrete resistance includes the two-sided shear resistance (the two sides of the hole, namely the front and the back, that is, the front side where the edge portion 36 is located and the back side where there is no edge portion 36) due to the shear force acting between the filled concrete in the through-hole 5 and the slab concrete, and the bearing resistance due to the compressive force acting from the small end face 31A and the side surface of the edge portion 36 to the slab concrete.

Number

[0052] The shear strength of the steel plate 31 can be obtained by the following formula.

Number

[0053] The shear strength due to the two-sided shear between the filled concrete in the through-hole 35 and the slab concrete is expressed by Equation [4].

Number

[0054] The shear strength due to the bearing resistance of the small end face 31A and the edge portion 36 is expressed by Equation [5]. The bearing area is the sum of the found areas of the small end face 31A and the edge portion 36. Also, the bearing area at this time (the influence area of the influence part of the concrete member that bears the bearing pressure (the bearing pressure generated on the grounding surface of the edge portion 36 and the small end face 31A spreads in the concrete as shown in FIGS. 17(B) and 17(C). If we assume that the spreading range is the influence part and a certain position supports the spreading force, then the area of the supporting range is interpreted as the bearing area (influence area). The certain position is assumed to support the bearing pressure at a position 1.5tc (tc: concrete slab thickness) away from the small end face 31A in this embodiment) is shown in FIGS. 17 to 19.

Number

[0055] Here, as shown in FIG. 17, the bearing area is in the range 1.5tc (tc: concrete slab thickness) in front of the headed shear connector.(However, the value of tc is limited by the aforementioned slab thickness G) Also, the bearing area is expressed by Equation [6]. However, when the distance between the small end faces 31A ( bp d e ) when the barring shear connectors are arranged in a single row is less than the slab thickness, the bearing area is given by Equation [7].

Number

Number

[0056] Also, in the reinforcement structure 100 in the above-described aspect, the joint members 30 may be a pair and arranged in parallel along the longitudinal direction of the steel member 10. Since the number of required joint members 30 on the steel member 10 does not change, by arranging the joint members 30 in parallel, the interval can be simply doubled compared to the series arrangement. As the interval increases, the number of arrangement locations is halved, so the obstacles for the person walking and working on the steel member 10 are reduced, and the on-site workability can be improved. The bearing areas in the case where the barring shear connectors are arranged in parallel are shown in FIGS. 18 and 19. The distance between the centers of the plate thicknesses of the flat steel plates 31 of the pair of joint members 30 is preferably not less than a eighth predetermined value PV8, for example, not less than 100 mm. This is because if there is not enough concrete on the protruding edge portion 36 side, there is no necessary bearing area against the bearing pressure, and the concrete bearing strength decreases (see Equation [6], etc.). Incidentally, the value of 100 mm is a value confirmed to exhibit performance in the test specimen, and if it becomes narrower than this, the performance may not be exhibited. As this value becomes wider, the bearing area can be increased as derived from Equation [6], etc., so the performance improves.

[0057] Here, when the protruding edge portion 36 faces inward, it is as shown in FIG. 18, and when the protruding edge portion 36 faces outward, it is as shown in FIG. 19. The bearing area per barring shear connector is obtained by Equation [8] and Equation [9], respectively. Here, when arranging the barring shear connectors in parallel, up to a set of two is used, and the distance between the centers of the plate thicknesses of the flat steel plates 31 of the barring shear connectors is br d gLet it be so. However, when the distance between the small end faces 31A of the barring connectors ( bp d e ) is less than the slab thickness, then t c = bp d e is set and the bearing area is calculated.

Number

Number

[0058] In the reinforcement structure 100 of the above-described aspect, when the respective flange portions 36 of the pair of joining members 30 face inward (see FIG. 18), the bearing areas of each other interfere as compared with the form shown in FIG. 19. Therefore, the bearing area per joining member 30 becomes smaller than that in the single-row arrangement (see FIG. 17 etc.). For this reason, it is considered that the concrete bearing capacity per joining member 30 decreases. The calculated value of the concrete bearing capacity is in the column of "Calculated value of the bearing capacity of concrete members". An example in the case of a single-row arrangement is about 200 kN, whereas an example in the case of a parallel arrangement is calculated to be about 160 kN because the bearing area decreases. However, it has been confirmed that the actual experimental results do not follow this tendency. In one example, the maximum load of 367.3 kN (in the fourth row) is exhibited, which is equivalent to twice that of an example in the case of a single-row arrangement. The factor is considered to be that the bearing pressure has increased (due to the flange portion 36 facing inward, the restraint effect of the concrete sandwiched between the steel plates 31).

[0059] The above-mentioned embodiment is one example of a preferred embodiment of the present invention, but is not limited thereto and can be modified in various ways without departing from the gist of the present invention. For example, in the above-mentioned embodiment, the flange 36 is provided to turn up the edge of the through hole 35 provided in the joint member 30, but this is merely one example of a preferred structure for destroying the steel plate 31 before the concrete member 20. Although not particularly shown, the steel plate 31 may be provided with only the flange (projection) 36 without the through hole 35. In short, the specific shape and structure are not limited as long as they function to ensure a sufficient area for the joint member 30 to catch on the concrete member 20 (i.e., the visible area). EXAMPLES

[0060] The inventors have conducted various tests to obtain evidence and verification results for the various theories, formulas, and preferred numerical ranges described so far. As a concrete example showing the actual state, images of (the steel plates 31 of) the joint members 30 deformed by shear action are shown in Fig. 20 for test specimen No. 2 (spacing 130 mm) and Fig. 21 for test specimen No. 3 (spacing 180 mm). In test specimen No. 2, the steel plate 31 on the upper side in the figure is not deformed at all, the shear force acting on the steel plate 31 is small, and the concrete between the steel plates 31 breaks first, which are the main points of the results when the spacing is set to 180 mm. less than Various adverse effects were confirmed when this was done (see Figure 20). On the other hand, in test specimen No. 3, it was confirmed that the steel plate 31 on the upper side in the figure was also deformed. It was also confirmed that the shear force acting on the steel plate 31 was large. Based on these causal relationships, it was considered that the concrete between the steel plates 31 did not break first (see Figure 21). [Table 1] [Industrial Applicability]

[0061] The joint member according to the present invention and the reinforcing structure including the joint member can be widely used in fields such as the building industry and the civil engineering and construction industry. [Explanation of symbols]

[0062] 10…Steel member 10X…Long side 10Y…Short side 20…Concrete member 21…Top end (upper end) 30…Burring shear connector (joint member) 31…Steel plate (flat base material) 31A…Narrow face 31B…End face 31f…Surface 32…Fillet weld 35…Through hole 36…Flange (protrusion) 36A…Measuring part 37…Flat part 100…Reinforcement structure (composite structure) 300…Deck plate (concrete raising material) A…Measuring area of steel plate B…Width of steel plate C…Overlap thickness of concrete member D…Cross-sectional area of the cross-section receiving the largest shear action F…Shearing force G…Slab thickness (thickness of concrete member 20) J…Distance from the narrow face in front of the direction of the shear force action of the burring shear connector to the slab end (end of the concrete member) K…Distance from the center of the plate thickness of the steel plate of the burring shear connector to the edge of the floor slab L…Distance between a set of burring shear connectors N…Deck plate rib height Ac…Bearing area fb…Concrete bearing strength F…Shearing force t…Plate thickness of steel plate X…Shearing force action direction

Claims

1. A composite structure including a steel member provided with a joint member and a concrete member in which the joint member is embedded, wherein the joint member has a plate-shaped flat plate portion, a through hole provided in the flat plate portion, and a protrusion protruding in a direction perpendicular to the surface of the flat plate portion provided in the flat plate portion, wherein a plurality of the joint members are intermittently and discontinuously arranged in a single row or in parallel in a shutter shape along the longitudinal direction of the steel member, with the protrusion facing in a direction perpendicular to the longitudinal direction of the steel member, wherein the distance between the centers of the through holes of the adjacent joint members along the longitudinal direction of the steel member is a first predetermined value: 180 mm or more, wherein the distance from the end of the concrete member in the longitudinal direction to the end of the joint member closest thereto is a second predetermined value: 250 mm or more, wherein the joint member includes two such joint members respectively arranged at two locations closest to both ends in the longitudinal direction of the concrete member, and at least two such joint members arranged between these two locations, the composite structure.

2. The composite structure according to claim 1, wherein when the composite structure is arranged in a structure and is in a use state, the upper end portion of the flat plate portion of the joint member of the composite structure and the concrete covering thickness representing the thickness between the upper end portion and the upper end of the concrete member are a third predetermined value or more.

3. The composite structure according to claim 1 or 2, wherein when the composite structure is arranged in a structure and is in a use state, the distance from the surface of the steel member to which the joint member is joined of the composite structure to the upper end of the concrete member is a fourth predetermined value or more.

4. The composite structure according to any one of claims 1 to 3, wherein when the composite structure is arranged in a structure and is in a use state, the protrusion of the joint member protrudes facing one side, and on the side where the protrusion does not protrude, the distance from the center of the plate thickness of the flat plate portion of the joint member to the concrete edge is a fifth predetermined value or more.

5. The composite structure according to any one of claims 1 to 3, wherein when the composite structure is arranged in a structure and is in a use state, the protrusion of the joint member protrudes facing one side, and on the side where the protrusion protrudes, the distance from the center of the plate thickness of the flat plate portion of the joint member to the concrete edge is a sixth predetermined value or more.

6. When the composite structure is arranged in a structure and in a use state, a concrete raising material is installed so as to sandwich the flat plate portion of the joining member, and the distance from the plate thickness center of the flat plate portion of the joining member to each of the concrete raising materials is equal to or greater than a seventh predetermined value. The composite structure according to any one of claims 1 to 5.

7. The raising amount of the concrete raising material is 50 mm or less. The composite structure according to claim 6.

8. One through hole is provided in the flat plate portion, and the protrusion is provided at the periphery of the through hole. The composite structure according to any one of claims 1 to 7.

9. The joining members are paired and arranged in parallel along the longitudinal direction of the steel member. The composite structure according to any one of claims 1 to 8.

10. The distance between the plate thickness centers of the flat plate-like base materials forming the pair of joining members is equal to or greater than an eighth predetermined value. The composite structure according to claim 9.

11. The protrusions of each of the pair of joining members face inward. The composite structure according to claim 9 or 10.

Images