Slab joint

Abstract

The present invention provides a slab joint that can improve bending followability by changing the behavior of the joint between precast slabs due to wheel loads to a bending-like behavior. [Solution] A slab joint 1 for joining two adjacent precast slabs C1, C1 comprises an embedded member 2 embedded in each of the two precast slabs C1, C1 and having a fitting recess 22, and a connecting member 3 whose ends are fitted across the fitting recess 22, with an opening 31 that penetrates horizontally formed in the connecting member 3.

Description

[Technical Field]

[0001] The present invention relates to a slab joint for connecting precast slabs, and more particularly to a slab joint having an opening that can improve bending followability by changing the behavior due to wheel load acting on the joint between precast slabs to a bending behavior. [Background technology]

[0002] Conventionally, when connecting precast bridge decks, loop reinforcement bars are placed in the gap formed by butting the connecting ends of the precast bridge decks together. These loop reinforcement bars project continuously from within the precast bridge deck in the direction of the bridge axis and bend and fold back in an arc shape within the gap. Loop reinforcement bars extending perpendicular to the bridge axis are then placed in the loop reinforcement bars, and the gap is filled with concrete to connect them.

[0003] For example, Patent Document 1 discloses a bridge deck joint fitting for connecting precast deck slabs, comprising a C-shaped joint fitting embedded in two opposing precast deck slabs and having fitting recesses, and an H-shaped joint fitting whose ends are fitted across these fitting recesses (see Claim 1 of the claims, paragraphs

[0041] to

[0056] of the specification, and Figures 3 to 6 of the drawings of Patent Document 1).

[0004] Furthermore, Patent Document 2 discloses a method for constructing a connection structure between a precast structural member and a time-hardening material, wherein, before casting the time-hardening material, a tension-introducing steel member is placed to connect one precast structural member and the other precast structural member, a tension-introducing steel member is used to apply tension to suppress cracking in the joint, and then a casting process is performed to cast the time-hardening material into the joint to connect and integrate the precast structural member and the time-hardening material, and in the tension-introducing process, the precast structural member is used to apply tension by engaging a fastening member such as a block or wedge with the joint or stud dowel (see Claim 1 of the claims in Patent Document 2, paragraphs

[0047] to

[0068] of the specification, and Figures 4 to 11 of the drawings).

[0005] However, the bridge deck joint fittings described in Patent Document 1 and the construction method for connecting precast structural members and time-hardening materials described in Patent Document 2 involve tightening bolts to fit the tapered surfaces of C-type joint fittings and H-type joint fittings together, introducing tension into the joint and creating a strong connection. However, when large bending stresses are transmitted to the connection due to wheel loads associated with vehicle traffic, the embedded joint fittings prevent sufficient reinforcement, reducing the load-bearing capacity of the deck at the ends, which could damage the precast deck.

[0006] Furthermore, Patent Document 3 discloses a concrete floor slab having a fixing device function for fixing the tensioning material and a joint receiving device function for receiving joints that connect adjacent concrete floor slabs, wherein the fixing surface is formed to face a slit provided on the opposing surface on the side opposite to the side of the adjacent concrete floor slab that faces the metal fittings, and the tensioning material is disposed between the metal fittings at both ends of the concrete floor slab, connected via joints, and prestress is introduced by the tensioning material (see Claim 1 of the claims in Patent Document 3, paragraphs

[0027] to

[0077] of the specification, Figures 1 to 13 of the drawings, etc.).

[0007] However, the concrete deck slab described in Patent Document 3 is connected by tensioning it with tension jacks to apply tension to the joints, resulting in a stronger connection than the bridge deck slab joint fittings described in Patent Document 1 or the construction method of the connection structure between precast structural members and time-hardening material described in Patent Document 2. However, the embedding of the joint fittings prevents sufficient reinforcement, and the load-bearing capacity of the deck slab at the ends remains reduced. Furthermore, the risk of damage to the precast deck slab when large bending stresses are transmitted to the connection points due to wheel loads from vehicle traffic cannot be eliminated.

[0008] On the other hand, Patent Document 4 discloses a joint structure for precast floor slabs comprising a first joint fitting embedded in each of two opposing precast floor slabs and having fitting holes, and a second joint fitting having a fitting portion that fits into the fitting holes and is connected by a connecting plate portion, wherein the connecting plate portion of the second joint fitting has a key insertion hole formed therein for inserting a reinforcing bar that serves as a shear key (see Claim 1 of the claims of Patent Document 4, paragraphs

[0007] to

[0017] of the specification, and Figures 1 to 5 of the drawings, etc.).

[0009] However, the key insertion holes in the joint structure of the precast floor slab described in Patent Document 4 are holes for inserting reinforcing bars that will serve as shear keys. Due to the embedding of the joint fittings, sufficient reinforcement cannot be provided, and the load-bearing capacity of the floor slab at the ends remains reduced. Therefore, it is not possible to eliminate the risk of damage to the precast floor slab when large bending stresses are transmitted to the joint due to wheel loads associated with vehicle traffic. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Patent No. 5787965 [Patent Document 2] Patent No. 6908988 [Patent Document 3] Patent No. 7372506 [Patent Document 4] Patent No. 3226986 [Overview of the project] [Problems that the invention aims to solve]

[0011] Therefore, the present invention was devised in view of the above-mentioned problems, and its objective is to provide a slab joint that can improve bending followability by changing the behavior of the joint between precast slabs due to wheel loads to a bending-like behavior. [Means for solving the problem]

[0012] The floor slab joint according to the first invention is a floor slab joint for joining two adjacent precast floor slabs, comprising: embedded members respectively embedded in the two precast floor slabs and having fitting recesses; and a connecting member whose both ends are fitted across the fitting recesses, wherein an opening penetrating in the horizontal direction is formed in the connecting member.

[0013] The floor slab joint according to the second invention is characterized in that, in the first invention, when the connecting member is fitted into the embedded members, the gap between the embedded members is narrower than the opening width in the bridge axis direction of the opening of the connecting member.

[0014] The floor slab joint according to the third invention is characterized in that, in the first invention, a screw portion for fixing the connecting member with bolts is formed in the embedded member.

[0015] The floor slab joint according to the fourth invention is characterized in that, in the first invention, the opening of the connecting member has an opening height in the height direction longer than the opening width in the bridge axis direction.

[0016] The floor slab joint according to the fifth invention is characterized in that, in the first invention, the opening of the connecting member has an opening height in the height direction shorter than the opening width in the bridge axis direction.

[0017] The floor slab joint according to the sixth invention is characterized in that, in the first invention, the opening height in the height direction perpendicular to the bridge axis direction of the opening of the connecting member is not less than half of the total height of the connecting member.

[0018] The floor slab joint according to the seventh invention is characterized in that, in the first invention, at least one of the upper side or the lower side of the opening of the connecting member has an arch shape.

[0019] The floor slab joint according to the eighth invention is characterized in that, in the first invention, at least a part of the connecting member has a truss structure.

[0020] The slab joint according to the ninth invention is characterized in that, in the first invention, at least a part of the connecting member has a rigid frame structure.

[0021] The slab joint according to the 10th invention is characterized in that, in the 7th invention, the opening has an arch shape on the upper side when a positive bending stress acts between the two precast slabs, and an arch shape on the lower side when a negative bending stress acts between the two precast slabs.

[0022] The slab joint according to the 11th invention is characterized in that, in the 8th invention, the opening is installed such that when a positive bending stress acts between the two precast slabs, the diagonal members of the truss structure open downwards, and when a negative bending stress acts between the two precast slabs, the diagonal members of the truss structure open upwards.

[0023] The slab joint according to the 12th invention is characterized in that, in the 7th invention, the connecting member has vertically extending flanges that prevent it from shifting horizontally relative to the embedded member.

[0024] The slab joint according to the 13th invention is characterized in that, in the 12th invention, the flange has a flange end face that is tapered and inclined with respect to the vertical plane, or the flange end face is formed in a direction parallel to the vertical plane.

[0025] The slab joint according to the 14th invention is characterized in that, in the first invention, the connecting member has vertically extending flanges that prevent it from shifting horizontally relative to the embedded member, and the horizontal cross-sectional shape of the flange end face of the flange is formed such that the flange end face and the embedded member can always be in partial contact.

[0026] The slab joint according to the 15th invention is characterized in that, in the 14th invention, the horizontal cross-sectional shape of the flange end face is arc-shaped.

[0027] The slab joint according to the 16th invention is, in the 14th invention, the width W of the flange. B The inner distance L of the flange housing portion that accommodates the flange of the embedded member. W The relationship is 1 <L W / W B It is characterized by satisfying the condition <10.

[0028] The slab joint according to the 17th invention is characterized in that, in the first invention, the connecting member has a chamfered edge along the edge of the opening, forming an inclined surface such that the area of ​​the opening narrows from the outside to the inside.

[0029] The slab joint according to the 18th invention is characterized in that, in the first invention, the upper surface of the connecting member is curved in an arch shape. [Effects of the Invention]

[0030] According to the first to eighteenth inventions, the connecting member has a small cross-sectional area, is lightweight, has a high second moment of area, and has excellent bending conductivity, so it can change the behavior of the joint between the floor slabs in response to wheel loads, etc., from shear behavior to bending behavior. As a result, it becomes possible to flexibly respond to bending stress acting on the joint between precast floor slabs, and the increased bending followability makes it possible to improve the resistance to torsion, which was difficult to achieve with conventional methods. [Brief explanation of the drawing]

[0031] [Figure 1] Figure 1 is an exploded perspective view showing the configuration of a slab joint according to one embodiment of the present invention. [Figure 2] Figure 2 is an overall perspective view showing the same slab joint. [Figure 3] Figure 3 is an overall plan view showing the floor slab joint shown above. [Figure 4] Figure 4 is a perspective view showing the embedded member of the slab joint described above. [Figure 5] Figure 5 shows the same buried member, where (a) is a front view, (b) is a right side view, and (c) is a top view. [Figure 6] Figure 6 is a perspective view showing the connecting member of the slab joint shown above. [Figure 7] Figure 7 shows the connecting member described above, where (a) is a front view, (b) is a right side view, and (c) is a top view. [Figure 8] Figure 8 is an explanatory diagram illustrating the positive and negative bending acting on the deck joint shown above, where (a) shows positive bending and (b) shows negative bending. [Figure 9] Figure 9 is an exploded perspective view showing the configuration of a slab joint according to a second embodiment of the present invention. [Figure 10] Figure 10 is an overall perspective view showing the same slab joint. [Figure 11] Figure 11 is an overall plan view showing the floor slab joint shown above. [Figure 12] Figure 12 is a perspective view showing a single connecting member of the same slab joint. [Figure 13] Figure 13 shows the same connecting member as above, with (a) being a front view, (b) being a right side view, and (c) being a top view. [Figure 14] Figure 14 is an explanatory diagram illustrating the arch effect. [Figure 15] Figure 15 is a perspective view showing a connecting member according to a modified example 1 of the slab joint of the present invention. [Figure 16] Figure 16 is a perspective view showing a connecting member according to a modified example 2 of the slab joint of the present invention. [Figure 17] Figure 17(a) is a schematic cross-sectional view showing a bending-resistant joint member with an opening in the vertical cross-section, and Figure 17(b) is a schematic cross-sectional view showing a shear-resistant joint member with a solid cross-section. [Figure 18] Figure 18 is an exploded perspective view showing the configuration of a slab joint according to a third embodiment of the present invention. [Figure 19] Figure 19 is an overall perspective view showing the same slab joint. [Figure 20] Figure 20 is an overall plan view showing the floor slab joint shown above. [Figure 21] Figure 21 is a perspective view showing the embedded member of the slab joint shown above. [Figure 22] Figure 22 shows the same buried member, where (a) is a front view, (b) is a right side view, and (c) is a top view. [Figure 23] Figure 23 is a perspective view showing the connecting member of the slab joint shown above. [Figure 24] Figure 24 shows the connecting member described above, where (a) is a front view, (b) is a right side view, and (c) is a top view. [Figure 25] Figure 25 is an overall plan view showing the same floor slab joint when there is a misalignment in the positional relationship between the embedded members. [Figure 26] Figure 26 is a side view showing a connecting member according to Modification 3, which is a modified example of the connecting member of the floor slab joint described above. [Modes for carrying out the invention]

[0032] Hereinafter, one embodiment of the slab joint according to the present invention will be described in detail with reference to the drawings.

[0033] [First Embodiment] First, the slab joint 1 according to the first embodiment of the present invention will be described using Figures 1 to 8. Figure 1 is an exploded perspective view showing the configuration of the slab joint 1 according to the first embodiment of the present invention, and Figure 2 is an overall perspective view showing the slab joint 1. Figure 3 is an overall plan view showing the slab joint 1.

[0034] As shown in Figures 1 to 3, the slab joint 1 according to this embodiment consists of a pair of embedded members 2, 2 which are embedded in the concrete of two precast slabs C1, C1 that are opposite each other, separated by a narrow joint J1 with a width of 50 mm or less that does not require reinforcement, a connecting member 3 which is attached across these embedded members 2, 2 to connect them, and fixing bolts 4 which fix the connecting member 3 to the embedded member 2, and has the function of joining two adjacent precast slabs C1, C1 separated by a joint J1.

[0035] (Buried component) Next, the embedded member 2 of the slab joint 1 will be described in detail using Figures 4 and 5. Figure 4 is a perspective view showing the embedded member 2 of the slab joint 1 by itself. Figure 5 is a diagram showing the embedded member 2 by itself, where (a) is a front view, (b) is a right side view, and (c) is a top view.

[0036] As shown in Figures 4 and 5, the embedded member 2 according to this embodiment is a cast iron fitting comprising a main body portion 20 and an anchor portion 21 protruding from the back side of the main body portion 20, opposite to the end face of the deck slab. The main body portion 20 is also provided with a D-shaped fitting recess 22 in plan view for accommodating one end of the connecting member 3. An opening 23 for inserting the connecting member 3 is formed on the deck slab end face side of this fitting recess 22. On the other hand, the outer peripheral surface 20a on the back side of the main body portion 20, where the anchor portion 21 protrudes, is a large-curvature arc in plan view, and the corners are also chamfered in an arc shape to form a rounded surface, resulting in a D-shape in plan view.

[0037] Furthermore, the main body portion 20 also has a pair of flange housing portions 24 that communicate with the fitting recess 22 and accommodate the flange 35 of the connecting member 3 described later. The outer inner surfaces 24a of these pair of flange housing portions 24 are inclined with respect to the vertical plane, and the distance between the outer inner surfaces 24a of the pair of flange housing portions 24 increases as you go upwards.

[0038] Furthermore, a trapezoidal bottom rib 26 is formed on the bottom surface 25 of the main body portion 20, which forms the bottom of the fitting recess 22, to engage with the bottom notch of the connecting member 3 described later. As shown in Figure 5(c), a threaded portion 27 is formed in the center of the bottom rib 26 in the longitudinal direction for bolting the fixing bolt 4.

[0039] As shown in Figure 5(c), the anchor portion 21 is a rectangular plate-shaped part in plan view with a predetermined thickness (e.g., 10 mm), and has two circular through holes 21a that penetrate vertically to increase the adhesion (anchoring force) with the embedded concrete. In this way, when concrete is poured, concrete enters the through holes 21a of the anchor portion 21, forming a shear key, which increases the adhesion (anchoring force) with the concrete at the through holes 21a. Furthermore, because it has a simpler structure compared to the anchor portion of other cotter-type floor slab joints described in Patent Documents 1 to 4, it is easy to demold from the mold during casting, less likely to form defects, and improves yield and work efficiency during manufacturing.

[0040] (Connecting component) Next, the connecting member 3 of the slab joint 1 will be described in detail using Figures 6 and 7. Figure 6 is a perspective view showing the connecting member 3 of the slab joint 1 by itself. Figure 7 is a diagram showing the connecting member 3 by itself, where (a) is a front view, (b) is a right side view, and (c) is a top view. Figure 8 is an explanatory diagram for illustrating the positive and negative bending acting on the slab joint 1, where (a) shows positive bending and (b) shows negative bending.

[0041] As shown in Figures 6 and 7, the connecting member 3 according to this embodiment is a metal fitting based on a cast iron connecting member body 30 which is oval in plan view and has a flat top surface. It has the function of joining the pair of buried members 2, 2 by fitting both ends across the respective fitting recesses 22, 22 of the pair of buried members 2, 2.

[0042] Furthermore, as shown in Figures 6 and 7(b), the connecting member body 30 has an opening 31, which is a through hole that penetrates horizontally. As described later, the presence of this opening 31 allows the cross-sectional area of ​​the member to be reduced while maintaining the second moment of area, thereby ensuring bending resistance with a small cross-sectional shape.

[0043] Furthermore, as shown in Figures 2, 3, and 7, when the connecting member 3 is joined to the pair of embedded members 2, 2, the gap G1 between the pair of embedded members 2, 2 is formed to be narrower than the opening width W1 in the bridge axis direction of the opening 31 (gap G1 < opening width W1).

[0044] Furthermore, as shown in Figure 7(b), the opening 31 of the connecting member 3 is formed such that the opening height H1 in the height direction perpendicular to the bridge axis direction is longer than the opening width W1 in the bridge axis direction (opening width W1 < opening height H1). By adopting this shape, the behavior of the slab joint 1 acting on the joint (joint portion J1) between the precast slabs C1, C1 due to the wheel load can be changed to a bending behavior, thereby improving bending followability.

[0045] Furthermore, by making the opening height H1 of the opening 31 of the connecting member 3 perpendicular to the bridge axis direction more than half of the total height H2 of the connecting member 3, as shown in Figure 7(b), the behavior of the slab joint 1 acting on the joint (joint portion J1) between the precast slabs C1, C1 due to the wheel load can be changed to a bending behavior, thereby further improving the bending followability.

[0046] As shown in Figure 7(b), the opening 31 of this connecting member 3 has an arched shape (arc-shaped in side view) on its upper side 31a, which changes the behavior of the slab joint 1 acting on the joint (joint J1) between precast slabs C1, C1 due to the wheel load to a bending behavior, thereby improving bending followability. In addition, because the upper side 31a of the opening 31 has an arched shape, even if the opening 31 is not filled with a filler material such as mortar, the arch effect can suppress a decrease in the load-bearing capacity of the slab joint 1. Note that, as shown in Figure 7(b), the lower side 31b of the opening 31 is planar (straight in side view).

[0047] However, as shown in Figure 8(a), when a positive bending stress acts on the joint (joint J1) between the two precast floor slabs C1, C1, it is preferable that the upper side 31a of the opening 31 be arched, as shown in Figures 6 and 7. As shown in Figure 8(b), when a negative bending stress acts on the joint (joint J1) between the two precast floor slabs C1, C1, it is preferable that the lower side 31b be arched, because the arch effect provides superior bending transmission.

[0048] Furthermore, the connecting member body 30 has a circular through-hole 32 that penetrates vertically from the top surface to the opening 31, and is configured so that a filler material such as non-shrink mortar can be filled into the opening 31 from above.

[0049] Furthermore, the connecting member body 30 has a pair of counterbore holes 33, 33 formed directly above the threaded portion 27 of each fitting recess 22, through which fixing bolts 4 for securing the connecting member 3 to the embedded member 2 are inserted, and for accommodating the bolt heads.

[0050] As shown in Figures 7(a) to 7(c), the upper part 33a is a large-diameter hole that accommodates the bolt head 4a of the fixing bolt 4, and the lower part 33b is a small-diameter hole through which the shaft portion 4b of the fixing bolt 4 is inserted (see also Figure 2).

[0051] As shown in Figures 7(a) and 7(b), a pair of trapezoidal notches 34 are formed on the bottom surface of the connecting member body 30, which is directly below the counterbore hole 33, and are hooked onto the bottom rib 26, which has a trapezoidal vertical cross-section.

[0052] In addition, two pairs of trapezoidal flanges 35 are provided on the side of the connecting member body 30, projecting outward at the position of the flange housing portion 24 mentioned above, for hooking the connecting member 3 onto the embedded members 2, 2. Furthermore, the flange end faces 35a of these flanges 35 are vertical surfaces, unlike the outer inner surface 24a of the flange housing portion 24. This is to accommodate installation errors between the two opposing precast floor slabs C1, C1. However, it goes without saying that, similar to the flange end face 35a' described later, it may also be an inclined surface that is inclined with respect to a vertical surface parallel to the outer inner surface 24a.

[0053] (Fixing bolts) As shown in Figure 1, the fixing bolt 4 is a commercially available socket head cap bolt consisting of a bolt head 4a with a hexagonal hole that can be rotated with a hex wrench, and a shaft portion 4b that connects to the bolt head 4a and has threads formed on its outer surface that engage with the threaded portion 27 of the embedded member 2.

[0054] [Second Embodiment] Next, the slab joint 1' according to the second embodiment of the present invention will be described using Figures 9 to 14. Figure 9 is an exploded perspective view showing the configuration of the slab joint 1' according to the second embodiment of the present invention, and Figure 10 is an overall perspective view showing the slab joint 1'. Figure 11 is an overall plan view showing the slab joint 1'.

[0055] The main difference between the slab joint 1' according to the second embodiment and the slab joint 1 according to the first embodiment described above is the shape of the connecting member 3'. This point will be explained, and identical components will be denoted by the same reference numerals, and their explanation will be omitted.

[0056] The slab joint 1' according to this embodiment, like the slab joint 1, consists of a pair of the aforementioned embedded members 2, 2 which are embedded in the concrete of two precast slabs C1, C1 that are opposite each other, separated by a narrow joint J1 with a width of 50 mm or less that does not require reinforcement, a connecting member 3' which is attached across these embedded members 2, 2 to connect them, and fixing bolts 4' which fix the connecting member 3' to the embedded member 2, and has the function of joining two adjacent precast slabs C1, C1 separated by a joint J1.

[0057] (Connecting component) Next, the connecting member 3' of the slab joint 1' will be explained in detail using Figures 12 and 13. Figure 12 is a perspective view showing the connecting member 3' of the slab joint 1' by itself. Figure 13 is a diagram showing the connecting member 3' by itself, with (a) being a front view, (b) a right side view, and (c) a top view. Figure 14 is an explanatory diagram for explaining the arch effect.

[0058] As shown in Figures 12 and 13, the connecting member 3' according to this embodiment is a metal fitting based on a cast iron connecting member body 30' which is rectangular in plan view, has a curved top surface, and is semi-circular in side view. It has the function of joining the pair of buried members 2, 2 by fitting both ends across the respective fitting recesses 22, 22 of the pair of buried members 2, 2.

[0059] Furthermore, as shown in Figures 12 and 13(b), the connecting member body 30' has an opening 31' which is a through hole that penetrates horizontally. Similar to the connecting member body 30 described above, the formation of this opening 31' allows the cross-sectional area of ​​the member to be reduced while maintaining the second moment of area, and bending resistance can be ensured with a small cross-sectional shape.

[0060] Furthermore, as shown in Figures 10, 11, and 13, when the connecting member 3' is joined to the pair of embedded members 2, 2, the gap G1 between the pair of embedded members 2, 2 is formed to be narrower than the opening width W1' in the bridge axis direction of the opening 31' (gap G1 < opening width W1').

[0061] Furthermore, as shown in Figure 13(b), the opening 31' of the connecting member 3' is formed such that the opening height H1' in the height direction perpendicular to the bridge axis direction is longer than the opening width W1' in the bridge axis direction (opening width W1' < opening height H1'). By adopting this shape, the behavior of the slab joint 1' acting on the joint (joint J1) between the precast slabs C1, C1 due to the wheel load can be changed to a bending behavior, thereby improving bending followability.

[0062] Furthermore, by making the opening height H1' of the opening 31' of the connecting member 3' perpendicular to the bridge axis direction more than half of the total height H2' of the connecting member 3', as shown in Figure 13(b), the behavior of the slab joint 1' acting on the joint (joint J1) between the precast slabs C1, C1 due to the wheel load can be changed to a bending behavior, thereby further improving the bending followability.

[0063] As shown in Figure 13(b), the upper part 31a' of this opening 31' is arch-shaped (arc-shaped in side view), which allows the behavior of the slab joint 1' acting on the joint (joint J1) between precast slabs C1, C1 due to the wheel load to be changed to a bending behavior, thereby improving bending followability. In addition, because the upper part 31a' of the opening 31' is arch-shaped, even if the opening 31' is not filled with a filler material such as mortar, the arch effect can suppress a decrease in the load-bearing capacity of the slab joint 1'. Note that, as shown in Figure 13(b), the lower part 31b' of the opening 31' is planar (straight in side view).

[0064] Thus, unlike the aforementioned connecting member 3, the connecting member 3' has an arched opening 31' at its upper side 31a', and the entire connecting member body 30' is arched. Therefore, as shown in Figure 14, when a vertical load is applied, the force is transmitted along the framework by the arched structure and reaches the support point. Similarly, when a positive bending stress, as shown in Figure 8(a), acts on the slab joint 1', the bending stress is transmitted as a compressive force to the fixing bolts 4', 4' at both ends due to the arched shape of the connecting member body 30', and can be counteracted by the tensile force on the bottom surface of the connecting member body 30' which is tightly connected to them. Therefore, the slab joint 1' according to this embodiment can efficiently counteract bending stress by reducing the volume of the cast iron portion, which has a higher specific gravity compared to fillers such as mortar.

[0065] Furthermore, the connecting member body 30' has a circular through-hole 32' in plan view that penetrates vertically from the top surface to the opening 31', and is configured so that a filler material such as non-shrink mortar can be filled into the opening 31' from above.

[0066] Furthermore, the connecting member body 30' has a pair of circular counterbore holes 33', 33' in plan view, directly above the threaded portion 27 of each fitting recess 22, through which fixing bolts 4 for securing the connecting member 3' to the embedded member 2 are inserted, and for accommodating the bolt heads. However, as shown in Figure 12, since the upper surface of the connecting member body 30' is a curved surface in plan view, the outer shape of the upper surface of the counterbore holes 33' is elliptical.

[0067] As shown in Figures 13(a) to (c), the upper part 33a' is a large-diameter hole that accommodates the bolt head 4a' of the fixing bolt 4', and the lower part 33b' is a small-diameter hole through which the shaft portion 4b' of the fixing bolt 4' is inserted (see also Figure 10).

[0068] As shown in Figures 13(a) and 13(b), a pair of trapezoidal notches 34' are formed on the bottom surface of the connecting member body 30', which is directly below the counterbore hole 33', and are hooked onto the bottom rib 26, which has a trapezoidal vertical cross-section.

[0069] In addition, two pairs of plate-shaped flanges 35' are provided on the side of the connecting member body 30' at the position of the flange housing portion 24, for hooking the connecting member 3' onto the embedded members 2, 2. Furthermore, the flange end faces 35a' of these flanges 35' are tapered, with the protrusion width increasing as it goes upwards, inclined with respect to a vertical plane parallel to the outer inner surface 24a of the flange housing portion 24. This is because contact between the connecting member and the embedded member is expected to introduce prestress in the tapered direction, and stress transmission from the connecting member to the embedded member is expected through contact between the members.

[0070] (Fixing bolts) As shown in Figures 9 and 10, the fixing bolt 4' is a commercially available socket head cap bolt consisting of a bolt head 4a' with a hexagonal socket that can be rotated with a hex wrench, and a shaft portion 4b' that connects to the bolt head 4a' and has threads formed on its outer surface that engage with the threaded portion 27 of the embedded member 2. However, this fixing bolt 4' is set to be shorter in length than the aforementioned fixing bolt 4 so that it can be accommodated in the counterbore hole 33'.

[0071] <Modified form of connecting member> (Connecting member relating to modified example 1) Next, the connecting member 5 according to Modification 1 will be described using Figure 15. Figure 15 is a perspective view showing the connecting member 5 according to Modification 1. The main difference between the connecting member 5 according to Modification 1 and the connecting member 3 according to the First Embodiment described above is that the shape of the opening 51 differs from the opening 31 described above. This point will be explained, and identical components will be denoted by the same reference numerals and their descriptions will be omitted.

[0072] As shown in Figure 15, the connecting member 5 according to the modified example 1 is a metal fitting based on a cast iron connecting member body 50 which is oval in plan view and has a flat top surface. It has the function of connecting the pair of buried members 2, 2 by fitting both ends across the respective fitting recesses 22, 22 of the pair of buried members 2, 2.

[0073] As shown in Figure 15, the connecting member body 50 has a pair of horizontally penetrating through holes, which are left and right openings 51. The formation of these openings 51 allows the cross-sectional area of ​​the member to be reduced while maintaining the second moment of area, and bending resistance can be ensured with a small cross-sectional shape.

[0074] The opening 51 is a symmetrical rectangular opening formed in the space between the flanges 35 and the partition wall 51c, which is formed in the center of the flat upper plate portion 51a and the flat lower plate portion 51b. The upper plate portion 51a and the lower plate portion 51b and the partition wall 51c are rigidly connected to each other, forming a so-called rigid frame structure.

[0075] Furthermore, the connecting member body 50 has a through hole 52 that penetrates vertically from the top surface to the opening 51, and is configured so that a filler material such as non-shrink mortar can be filled into the opening 51 from above. However, because a partition wall 51c is formed in the center of the aforementioned circular through hole 32, this through hole 52 is divided into two crescent-shaped through holes 52, 52.

[0076] Note that the counterbore 33, notch 34, and flange 35 have the same configuration as the connecting member 3 described above, so their explanation will be omitted.

[0077] (Connecting member relating to modified example 2) Next, the connecting member 6 according to the modified example 2 will be described using Figure 16. Figure 16 is a perspective view showing the connecting member 6 according to the modified example 2. The main difference between the connecting member 6 according to the modified example 2 and the connecting member 3 according to the first embodiment described above is that the shape of the opening 61 differs from that of the opening 31 described above. This point will be explained, and identical components will be denoted by the same reference numerals and their descriptions will be omitted.

[0078] The connecting member 6 according to the modified example 2, as shown in Figure 16, is a metal fitting based on a cast iron connecting member body 60 which is oval in plan view and has a flat top surface. It has the function of connecting the pair of buried members 2, 2 by fitting both ends across the respective fitting recesses 22, 22 of the pair of buried members 2, 2.

[0079] As shown in Figure 16, the connecting member body 60 has an opening 61, which is a through hole that penetrates horizontally. By forming the opening 61, the cross-sectional area of ​​the member can be reduced while maintaining the second moment of area, and bending resistance can be ensured with a small cross-sectional shape.

[0080] The opening 61 is formed by a truss structure in which a flat upper plate portion 61a and a flat lower plate portion 61b are connected by multiple diagonal members 61c, and the gap in the truss structure between the aforementioned flanges 35 becomes the opening. These diagonal members 61c are installed so as to spread outwards from one another as they extend downwards.

[0081] However, it is preferable that the diagonal members 61c of this opening 61 are installed so that they open downwards when a positive bending stress acts between the two precast floor slabs, as shown in Figure 8(a), and so that they open upwards when a negative bending stress acts between the two precast floor slabs, as shown in Figure 8(b). This is because such installation allows for a more flexible response to bending stress due to the arch effect, thereby improving bending followability.

[0082] Note that the through hole 32, counterbore hole 33, notch 34, and flange 35 have the same configuration as the connecting member 3 described above, so their explanation will be omitted.

[0083] <Cross-sectional performance> Next, using Figure 17 and Table 1, we will perform a calculation comparison of cross-sectional properties such as the second moment of area to examine the difference in bending transmission between commercially available cotter-type floor slab joints with solid cross-sections, such as those described in Patent Documents 1 to 3, and the bending-resistant joint members corresponding to the connecting members according to the present invention. Figure 17 is a cross-sectional view of joint members related to bending resistance and shear resistance, where (a) shows a bending-resistant joint fitting and (b) shows a shear-resistant joint fitting.

[0084] Table 1 below is a comparative calculation table for examining the rate of weight reduction achieved by comparing the weight from the cross-sectional area after adjusting the bending resistance type joint member with an opening in the vertical cross-section shown in Figure 17(a) and the shear resistance type joint member with a solid cross-section shown in Figure 17(b) so that their second moment of area is the same.

[0085] [Table 1]

[0086] As shown in Table 1, the second moment of area of ​​the steel section was calculated by making the steel area the same for both the bending-resistant and shear-resistant types. Generally, when calculating the stress acting on steel, the larger the second moment of area, the greater the stress reduction. Thus, when the stress acting on the bending-resistant and shear-resistant joint members is made the same, the bending-resistant steel joint member (joint fitting) has the advantage of being able to have a smaller cross-sectional area. Therefore, the bending-resistant joint member can effectively reduce the stress acting on the steel with a smaller steel cross-sectional area.

[0087] Furthermore, assuming the same second moment of area, the stress generated at the outermost edge of the steel material will be the same. On the other hand, the cross-sectional area of ​​the bending-resistant steel material is 1 / 3 that of the shear-resistant steel material. When this cross-sectional area is multiplied by the specific gravity of the steel material of the joint member to convert the weight, the calculation results show that the bending-resistant type contributes to a 67% weight reduction compared to the shear-resistant type. However, this weight reduction is limited to the part with the joint opening.

[0088] [Third Embodiment] Next, the slab joint 1" according to the third embodiment of the present invention will be described using Figures 18 to 24. Figure 18 is an exploded perspective view showing the configuration of the slab joint 1" according to the third embodiment of the present invention, and Figure 19 is an overall perspective view showing the slab joint 1". Figure 20 is an overall plan view showing the slab joint 1".

[0089] As shown in Figures 18 to 20, the slab joint 1" according to this embodiment, similar to the slab joint 1 described above, consists of a pair of embedded members 2",2" which are embedded in the concrete of two precast slabs C1, C1 facing each other with a narrow joint J1 of 50 mm or less in width that does not require reinforcement, a connecting member 3" which is attached across these embedded members 2",2" to connect them, and fixing bolts 4" which fix the connecting member 3" to the embedded member 2", and has the function of joining two adjacent precast slabs C1, C1 with a joint J1 in between.

[0090] (Buried component) Next, the embedded member 2" of the slab joint 1" will be explained in detail using Figures 21 and 22. Figure 21 is a perspective view showing the embedded member 2" of the slab joint 1" by itself. Figure 22 is a diagram showing the embedded member 2" by itself, where (a) is a front view, (b) is a right side view, and (c) is a top view.

[0091] As shown in Figures 21 and 22, the embedded member 2" according to this embodiment is a cast iron fitting comprising a main body 20" and an anchor portion 21" protruding from the back side opposite the end face of the deck slab of the main body 20". The main body 20" is also provided with a cross-shaped fitting recess 22" in plan view for accommodating one end of the connecting member 3".

[0092] Furthermore, an opening 23" for inserting the connecting member 3" is formed on the end face side of the floor slab of this fitting recess 22". On the other hand, the outer peripheral surface 20a" on the back side of the main body 20" from which the anchor portion 21" is attached has a large curvature and is shaped like a circular arc in plan view, and the corners are also chamfered in a circular arc shape. In addition, the outer surface 20b" of the flange housing portion 24" of the main body 20" has its widest point in the center in the height direction, making it easy to remove from the mold during casting.

[0093] Furthermore, the main body portion 20" also has a pair of flange housing portions 24" which communicate with the fitting recess 22" and accommodate the flange 35" of the connecting member 3" described later. The inner surfaces 24a" of this pair of flange housing portions 24" are inclined with respect to the vertical plane, and the distance between the inner surfaces 24a" of the pair of flange housing portions 24" increases as you go upwards.

[0094] Furthermore, as shown in Figure 22(c), a threaded portion 26" for bolting a fixing bolt 4" is formed on the bottom surface 25" of the main body portion 20" which forms the bottom of the fitting recess 22". Note that the bottom surface 25" of the embedded member 2" according to this embodiment does not have a rib corresponding to the bottom surface rib 26" of the embedded member 2 described above, and has a simplified configuration in which the threaded portion 26" is directly protruding. As a result, the angle of the connecting member 3" relative to the embedded member 2" can be adjusted, and as will be described later, even if there is a construction error in the installation position of the precast deck slab C1 and a displacement occurs in the gap G1 in the bridge axis direction X or the direction perpendicular to the bridge axis Y, the construction error can be absorbed by adjusting the angle of the connecting member 3".

[0095] As shown in Figure 22(c), the anchor portion 21" consists of a rectangular plate-shaped anchor plate 21a" with a predetermined thickness in plan view, and a hexagonal rod-shaped end anchor 21b" formed at the end of the anchor plate 21a" with the widest part in the center in the height direction. In addition, two circular through holes 21c" are drilled in the anchor plate 21a" to increase the adhesion (anchoring force) with the embedded concrete. When concrete is poured, concrete enters the through holes 21c" of the anchor plate 21a" to form shear keys, and the adhesion (anchoring force) with the concrete is increased at the through holes 21c". Furthermore, the anchoring force of the end anchor 21b" is added, increasing the anchoring strength and making it possible to resist the force that pulls the embedded member 2" out from the end of the embedded precast floor slab C1.

[0096] As described above, the embedded member 2" according to this embodiment has a shape that facilitates demolding from the mold during casting, with the width at the center in the height direction being the greatest overall. Compared to the embedded member 2 according to the first and second embodiments, it is easier to demold from the mold during casting, less likely to form defects, and improves yield and work efficiency during manufacturing.

[0097] (Connecting component) Next, the connecting member 3 of the slab joint 1 will be described in detail using Figures 23 and 24. Figure 23 is a perspective view showing the connecting member 3" of the slab joint 1" by itself. Figure 24 is a diagram showing the connecting member 3" by itself, where (a) is a front view, (b) is a right side view, and (c) is a top view.

[0098] As shown in Figures 23 and 24, the connecting member 3" according to this embodiment is a metal fitting based on a cast iron connecting member body 30" which has a horizontally elongated hexagonal shape in plan view and a flat top surface. It has the function of joining the pair of embedded members 2",2" by fitting both ends across the respective fitting recesses 22",22" of the pair of embedded members 2",2" mentioned above.

[0099] Furthermore, as shown in Figures 23 and 24(b), the connecting member body 30" has an opening 31" which is a through hole that penetrates horizontally. As mentioned above, this opening 31" allows the cross-sectional area of ​​the member to be reduced while maintaining the second moment of area, and bending resistance can be ensured with a small cross-sectional shape.

[0100] Furthermore, as shown in Figures 19, 20, and 24(b), when the connecting member 3" is joined to the pair of embedded members 2",2", the gap G1 between the pair of embedded members 2",2" is formed to be narrower than the opening width W1" in the bridge axis direction of the opening 31" (gap G1 < opening width W1).

[0101] Furthermore, as shown in Figure 24(b), the opening 31" of the connecting member 3" is formed such that the opening height H1" in the height direction perpendicular to the bridge axis direction is shorter than the opening width W1" in the bridge axis direction (opening width W1" > opening height H1"). If the opening height H1" is large, the bending resistance area decreases, and the rigidity drops too low. On the other hand, if the opening height H1" is too small, the cross-sectional area becomes larger than necessary, increasing the weight of the connecting member 3" and raising costs. Conversely, a larger opening width W1" is advantageous for weight reduction, but if the opening width W1" is too large, it approaches the bolt opening and increases the risk of failure.

[0102] Therefore, by setting the opening width W1" > opening height H1", an appropriate balance of rigidity can be ensured, and the rigidity in the height direction of the connecting member 3" can be expected, thereby reducing the risk of failure of the opening 31". In other words, by setting the dimension of the opening height H1" of the connecting member 3" to be smaller than the dimension of the opening width W1", it is possible to ensure appropriate rigidity in the height direction of the connecting member 3" while preventing the cross-sectional area from becoming unnecessarily large, thereby suppressing an increase in member weight and cost. In addition, by ensuring an appropriate opening width W1" while suppressing the opening height H1", stress concentration near the bolt opening can be alleviated and the burden shifted to the bending resistance part, thereby reducing the risk of failure of the connecting member 3". This improves the structural stability and reliability of the connecting member 3".

[0103] Furthermore, by making the opening height H1" of the opening 31" of the connecting member 3" more than half of the total height H2" of the connecting member 3", as shown in Figure 24(b), the behavior of the floor slab joint 1 acting on the joint (joint portion J1) between the precast floor slabs C1, C1 due to the wheel load can be changed to a bending behavior, thereby further improving the bending followability.

[0104] Unlike the aforementioned connecting member 3, the connecting member body 30" does not have a through hole corresponding to the through hole 32, which penetrates from the top surface to the opening 31". Instead, a chamfered surface is formed along the edge of the opening 31", so that the area of ​​the opening 31" narrows from the outside to the inside. Therefore, when filling with filler material, air in the opening 31" can be easily released from the inside to the outside without forming an air pocket.

[0105] Furthermore, as shown in Figures 23 and 24, the connecting member body 30" has a pair of countersunk holes 32", 32", formed directly above the threaded portion 26" of each fitting recess 22", through which fixing bolts 4" that secure the connecting member 3" to the embedded member 2" are inserted, and for housing the bolt heads.

[0106] As shown in Figures 24(a) to (c), the upper part 32a" is a large-diameter hole that accommodates the bolt head 4a" of the fixing bolt 4", and the lower part 32b" is a small-diameter hole through which the shaft portion 4b" of the fixing bolt 4" is inserted (see also Figures 18 to 20).

[0107] Furthermore, the counterbore hole 32" has an air vent groove 32c" formed therein so that a filler material such as mortar can be filled without any gaps around the fixing bolt 4". This allows the area around the bolt head 4a" of the fixing bolt 4", which is prone to having unfilled areas, to be filled with the filler material without any gaps.

[0108] In addition, on the side of the connecting member body 30", two pairs of arc-shaped flanges 33" are provided projecting outward at the position of the flange housing portion 24" mentioned above, for hooking the connecting member 3" onto the embedded members 2",2". Furthermore, as shown in Figures 23, 24(a), and 24(c), the flange end face 33a" of this flange 33" is an arc-shaped surface in plan view, and also an arc-shaped curved surface in side view when viewed in a direction perpendicular to the plate surface of the flange 33".

[0109] Therefore, as shown in Figure 25, even if there is a construction error in the installation position of the precast floor slab C1 and there is a misalignment in the positional relationship between the embedded members 2" into which the connecting member 3" is fitted, line contact is always ensured between the flange end face 33a" of the flange 33" of the connecting member 3" and the inner surface of the flange housing 24" of the embedded member 2", allowing stress transmission between the embedded members 2" fitted together via the connecting member 3". However, the horizontal cross-sectional shape of the flange end face 33a" is not limited to an arc shape; it is sufficient if it is formed so that the flange end face 33a" and the flange housing 24" can always be in partial contact. Figure 25 is an overall plan view showing the floor slab joint 1" when there is a misalignment in the positional relationship between the embedded members 2".

[0110] Furthermore, as shown in Figures 20 and 25, the width W of the flange 33” B And the inner distance L of the flange housing portion 24" of the embedded member 2" W The relationship is 1 <L W / W BIt is preferable to satisfy <10. Even if there is a construction error in the installation position of the precast floor slab C1 and there is a deviation in the bridge axis direction X or the direction perpendicular to the bridge axis Y in the gap G1, the construction error can be absorbed by adjusting the angle of the connecting member 3”. As described above, the line contact between the flange end face 33a” and the inner surface of the flange housing portion 24” is always ensured, and stress transmission between the embedded members 2” fitted through the connecting member 3” which is a metal member without using a filler becomes possible. According to the floor slab joint 1” according to the present embodiment, deviations in the bridge axis direction X and the direction perpendicular to the bridge axis Y can both be accommodated up to ±10 mm, and the rotation of the connecting member 3” can also be accommodated up to ±5°.

[0111] In the present embodiment shown in the figure, the width W of the flange 33” B = 20 mm, and the inner interval L of the flange housing portion 24” W = 50 mm. When L W / W B = 1, there is a possibility that the flange 33” may not fit into the flange housing portion 24”. And when L W / W B ≧ 10, the overall length of the floor slab joint 1” exceeds 250 mm, interfering with the internal reinforcement of the precast floor slab C1, increasing the overall weight and leading to an increase in costs such as an increase in mortar filling, which is not preferable.

[0112] (Fixed bolt) As shown in FIG. 18, the fixed bolt 4” is a general commercially available bolt, and includes a bolt head 4a” and a shaft portion 4b” having a thread formed on the outer peripheral surface thereof that is screwed with the threaded portion 26” of the embedded member 2” connected to the bolt head 4a”.

[0113] <Modification example of the connecting member 3”> FIG. 26 is a side view showing a connecting member 7 according to a modification example 3 which is a modification example of the connecting member 3” of the floor slab joint 1” according to the third embodiment. As shown in FIG. 26, the difference between the connecting member 7 according to the modification example 3 and the connecting member 3” of the floor slab joint 1” according to the aforementioned third embodiment is only that the upper surface of the connecting member body 70 has an arch shape (arc shape in side view). Therefore, the same components are denoted by the same reference numerals and detailed description is omitted.

[0114] As shown in Figure 26, since the entire connecting member body 70 has an arch shape, just as the force applied to the bridge is transmitted to the ground through the abutment as a compressive force, when a positive bending stress acts on the deck joint 1", the arch shape of the connecting member body 70 transmits that bending stress as a compressive force to the fixing bolts 4" at both ends, and the tensile force on the bottom surface of the connecting member body 70, which is tightly fastened to them, can counteract it. Therefore, the volume of the cast iron portion, which has a higher specific gravity than fillers such as mortar, can be reduced, and the bending stress can be counteracted efficiently.

[0115] According to the slab joint 1 to the slab joint 1'' with an opening according to the first embodiment described above (including cases where connecting members 3, 3', 3) are replaced with connecting members 5, 6, 7), the opening is formed in the connecting member, which allows the cross-sectional area of ​​the member to be reduced while maintaining the second moment of area, and thus ensures bending resistance with a small cross-sectional shape. In other words, with the slab joint 1 to the slab joint 1'', the cross-sectional area of ​​the connecting member is small, the weight is light, the second moment of area is high, and the bending transmission is excellent, so the behavior of the joint between slab joints in response to wheel loads etc. can be changed from shear behavior to bending behavior, and it becomes possible to flexibly respond to bending stress acting on the joint between precast slabs, and the bending followability is improved, which also improves the resistance to torsion, which was difficult in the past.

[0116] Furthermore, with slab joints 1 to 1”, the upper parts 31a and 31a' of the openings 31, 31', and 31'' are arched. Therefore, even if the openings are not filled with mortar or other filling material, the arch effect can suppress the reduction in the load-bearing capacity of slab joints 1 to 1''.

[0117] Furthermore, since the entire connecting member body 30' and connecting member body 70 are arch-shaped, just as the force applied to the bridge is transmitted to the ground through the abutment as a compressive force, when a positive bending stress acts on the deck joint 1', that bending stress is transmitted as a compressive force to the fixing bolts 4', 4', 4'' at both ends due to the arch shape of the connecting member body 30' (connecting member body 70), and can be counteracted by the tensile force on the bottom surface of the connecting member body 30' (connecting member body 70) that is tightly fastened to them. Therefore, the volume of the cast iron portion, which has a higher specific gravity compared to fillers such as mortar, can be reduced, and bending stress can be counteracted efficiently.

[0118] In addition, according to the slab joint 1" of the third embodiment (including the case in which the connecting member 3" is replaced with the connecting member 7), two pairs of arc-shaped flanges 33" are provided protruding outward from the side surface of the connecting member body 30" at the position of the flange housing portion 24" mentioned above, for hooking the connecting member 3" onto the embedded members 2",2". The flange end faces 33a" are arc-shaped in both plan view and side view, so even if there is a construction error in the installation position of the precast slab C1 and there is a misalignment in the positional relationship between the embedded members 2" into which the connecting member 3" is fitted, line contact is always ensured between the flange end faces 33a" of the flange 33" of the connecting member 3" and the inner surface of the flange housing portion 24" of the embedded member 2", allowing stress transmission between the embedded members 2" fitted together via the connecting member 3".

[0119] Furthermore, according to the third embodiment of the slab joint 1" (including the case in which the connecting member 3" is replaced with the connecting member 7), the width W of the flange 33" B And the inner distance L of the flange housing portion 24" of the embedded member 2" W The relationship is 1 <L W / W B Since the condition <10 is met, even if there is a construction error in the installation position of the precast deck slab C1 and a displacement occurs in the gap G1 in the bridge axis direction X or the direction perpendicular to the bridge axis Y, the construction error can be absorbed by adjusting the angle of the connecting member 3”.

[0120] Furthermore, according to the slab joint 1" of the third embodiment (including the case in which the connecting member 3" is replaced with the connecting member 7), a chamfered edge is formed along the edge of the opening 31" so that the area of ​​the opening 31" narrows from the outside to the inside, thereby creating an inclined surface. As a result, when filling with filler material, air in the opening 31" can be easily released from the inside to the outside. Thus, a through hole corresponding to the through hole 32 that penetrates vertically from the upper surface of the connecting member 3" to the opening 32" can be eliminated.

[0121] Although the floor slab joints 1 to 1" having openings according to the first to third embodiments of the present invention have been described in detail above, the embodiments described above or illustrated are merely examples of embodiments that have been materialized in carrying out the present invention. Therefore, the technical scope of the present invention should not be interpreted as being limited by these embodiments.

[0122] In particular, although cast iron was used as an example for the embedded member 2 and connecting members 3-3”, the embedded and connecting fittings are not limited to iron or steel. Any fitting formed by casting or forging is acceptable. Furthermore, it goes without saying that any member made of other materials such as resin or FRP can be used as long as it has the strength and rigidity to withstand the stresses such as bending stress and shear stress acting on the slab joint installed at the joint between precast slabs C1, C1.

[0123] If the opening heights H1, H1', ​​H1'' of the connecting member in the height direction perpendicular to the bridge axis direction are set to be more than half of the total height H2, H2', H2'' of the connecting member in the height direction perpendicular to the bridge axis direction, the behavior of the slab joint 1 acting on the joint (joint J1) between precast slabs C1, C1 due to the wheel load can be changed to a bending behavior, thereby further improving the bending followability.

[0124] The opening of the connecting member is formed such that the opening height H1 in the height direction perpendicular to the bridge axis is longer than the opening width W1 in the bridge axis direction (opening width W1 < opening height H1). Alternatively, the opening heights H1, H1', ​​H1'' in the height direction perpendicular to the bridge axis of the opening of the connecting member are formed such that the opening height H1'' in the height direction perpendicular to the bridge axis is shorter than the opening width W1'' in the bridge axis direction (opening width W1'' > opening height H1''). However, the opening width W1 in the bridge axis direction and the opening height H1 in the height direction perpendicular to the bridge axis may be of equal length.

[0125] As a modified example of the connecting member, a partition wall 51c is formed in the opening 51 between a flat upper plate portion 51a and a flat lower plate portion 51b, creating a symmetrical rectangular opening in the space between each flange 35 and the partition wall 51c. However, the opening does not have to be symmetrical as long as openings are formed on both sides. Furthermore, the partition wall 51c of the opening 51 may be formed in the opening 51 so that it is parallel to the upper plate portion 51a or the flat lower plate portion 51b (in the direction of the bridge axis), and the openings above and below the partition wall 51c may be symmetrical or asymmetrical. This configuration allows the opening to withstand shear forces. [Explanation of Symbols]

[0126] 1,1': Slab joint 2,2”: Buried component 20,20”: Main body 20a: Outer surface 21,21”: Anchor section 21a”: Anchor plate 21b”: End anchor 21a, 21c”: Through hole 22,22”: Mating recess 23,23”: Opening 24,24”: Flange housing 24a,24a”:Outer inner surface 25,25”: Base 26: Bottom ribs 27, 26": Screw portion 3,3',3”,5,6,7: Connecting members 30, 30’, 30”, 50, 60: Connection part body 31, 31’, 31”, 51, 61: Opening W1, W1’, W1”: Opening width H1, H1’, H1”: Opening height H2, H2’, H2”: Overall height 31a, 31a’: Upper side 31b, 31b’: Lower side 51a, 61a: Upper plate part 51b, 61b: Lower plate part 51c: Partition wall 61c: Diagonal member 32, 32’, 52: Through hole 33, 33’, 32”: Counterbore hole 33a, 33a’, 32a”: Upper part 33b, 33b’, 32b”: Lower part 34, 34’: Recess 35, 35’, 33”: Flange 35a, 35a’, 33a”: Flange end face 4, 4’, 4”: Fixing bolt 4a, 4a’, 4a”: Bolt head 4b, 4b’, 4b”: Shaft part C1: Precast floor slab J1: Joint part

Claims

1. A slab joint for joining two adjacent precast slabs, The two precast floor slabs each include an embedded member having a fitting recess, and a connecting member whose ends are fitted across these fitting recesses. The connecting member has an opening that penetrates horizontally. A deck slab joint characterized by the following.

2. When the connecting member is fitted into the buried member, the gap between the buried members is narrower than the opening width of the opening of the connecting member in the bridge axis direction. A slab joint according to claim 1, characterized by the following:

3. The buried member has a threaded portion for fixing the connecting member with a bolt. A slab joint according to claim 1, characterized by the following:

4. The opening of the connecting member has an opening height in the height direction that is greater than the opening width in the bridge axis direction. A slab joint according to claim 1, characterized by the following:

5. The opening of the connecting member has an opening height in the height direction that is shorter than the opening width in the bridge axis direction. A slab joint according to claim 1, characterized by the following:

6. The height of the opening in the connecting member perpendicular to the bridge axis direction is at least half of the total height of the connecting member. A slab joint according to claim 1, characterized by the following:

7. At least one of the upper or lower part of the opening of the connecting member is arched. A slab joint according to claim 1, characterized by the following:

8. The aforementioned connecting member has at least a portion of its structure as a truss. A slab joint according to claim 1, characterized by the following:

9. The aforementioned connecting member has at least a portion of it in a rigid frame structure. A slab joint according to claim 1, characterized by the following:

10. The opening is arched at the top when a positive bending stress acts between the two precast floor slabs, and arched at the bottom when a negative bending stress acts between the two precast floor slabs. A slab joint according to claim 7, characterized by the following:

11. The opening is installed such that when a positive bending stress acts between the two precast slabs, the diagonal members of the truss structure open downwards, and when a negative bending stress acts between the two precast slabs, the diagonal members of the truss structure open upwards. A slab joint according to claim 8, characterized by the following:

12. The connecting member has vertically extending flanges that prevent it from shifting horizontally relative to the embedded member. A slab joint according to claim 7, characterized by the following:

13. The flange is such that the flange end face is tapered and inclined with respect to the vertical plane, or the flange end face is formed parallel to the vertical plane. A slab joint according to claim 12, characterized by the above.

14. The connecting member has vertically extending flanges that prevent it from shifting horizontally relative to the embedded member, and the horizontal cross-sectional shape of the flange end face is formed such that the flange end face and the embedded member can partially come into contact. A slab joint according to claim 1, characterized by the following:

15. The horizontal cross-sectional shape of the flange end face is arc-shaped. A slab joint according to claim 14, characterized by the following:

16. The width W of the flange B The inner distance L of the flange housing portion that accommodates the flange of the embedded member. W The relationship is 1 < L W / W B <Makes the condition 10 A slab joint according to claim 14, characterized by the following:

17. The connecting member has an inclined surface formed by chamfering along the edge of the opening such that the area of ​​the opening narrows from the outside to the inside. A slab joint according to claim 1, characterized by the following:

18. The upper surface of the connecting member is curved in an arch shape. A slab joint according to claim 1, characterized by the following:

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