Joint structure and forming method for PCa deck slabs of road bridges

Abstract

To provide a joint structure of road bridge PCa floor slabs that can effectively introduce prestress force only to a longitudinal joint without parallelly moving two PCa floor slabs connected to each other at the same time, and a formation method therefor.SOLUTION: In a joint structure 100 of road bridge PCa floor slabs to which a first joint 30 provided at a first PCa floor slab 10 and a second joint 40 provided at a second PCa floor slab 20 are connected, a first shaft body 31 forming the first joint 30 is projected to a side from a first joint end surface 11, the second joint 40 has a box 42 inside the second PCa floor slab 20, and an inside of the box 42 includes a worm gear 43, a worm wheel 44 and a second shaft body 41 projected to a side from a second joint end surface 21. The first shaft body 31 and the second shaft body 41 are strained by screwing to both ends of a screw groove 61 penetrating a coupler 60 in a gap G between the first joint end surface 11 and the second joint end surface 21, and the gap G is obstructed with a filling material 70.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a joint structure for PCa deck slabs of road bridges and a method for forming the same. [Background technology]

[0002] On expressways that are around 50 years old or older, the deck slabs have deteriorated and their rigidity has decreased, so replacement work with new deck slabs is being carried out. In conventional expressway deck replacement work, one lane (either the inbound or outbound lane) that has the deck to be replaced (for example, an existing RC (Reinforced Concrete) deck) is completely closed to traffic, and the driving lane and passing lane on the other lane are restricted to two-way traffic, allowing the deck replacement work to be carried out while the expressway remains in operation. However, this method can make it difficult to enforce two-way traffic regulations on heavy traffic routes, interchanges, lanes located near service areas, and the like. Therefore, the half-section deck replacement method is one method that makes it possible to replace decks even in such lanes.The half-section deck replacement method is a construction method in which the deck to be replaced is divided into the driving lane side and the passing lane side, and the existing deck is removed for each half section due to lane restrictions and replaced with a new precast concrete deck (PCa: Precast Concrete deck, precast deck).With this method, it is possible to replace the deck while keeping part of both the inbound and outbound lanes in service, for example.

[0003] In the half-section deck replacement method, a vertical joint perpendicular to the bridge axis is installed between the PCa deck installed first and the PCa deck installed later. However, there are various challenges in constructing this vertical joint. One problem is that when attempting to apply rebar loop joints to vertical joints, the rebars are positioned at the same height and interfere with each other, making horizontal movement for alignment impossible. Patent Document 1 proposes a joint structure for PCa floor panels that uses such loop joints, but this joint structure also has the same inherent problem. Another issue is that when attempting to apply curved prestressed concrete (PC) steel members with intermediate anchorages, bending occurs due to eccentric axial forces, and furthermore, construction scaffolding is required on the underside of the deck. Another issue is that when attempting to apply joints in which PC steel rods are buried in advance and joined with couplers, it is virtually impossible to align the threads of the PC steel rods on both the precast prestressed concrete (PCaPC) deck slab that is installed first and the PCaPC deck slab that is installed later. Furthermore, another issue is that when prestressing is attempted to be introduced to the entire structure later by using PC cables that pass through the PCaPC deck slabs that are installed first and the PCaPC deck slabs that are installed later, additional prestressing force will be added to the prestressing force that has already been introduced to each PCaPC deck slab, resulting in excessive prestressing force acting on general parts of the PCaPC deck slab other than the vertical joints, resulting in severe compressive stress. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-49621 Summary of the Invention [Problem to be solved by the invention]

[0005] Thus, when applying the half-section deck replacement method, which enables efficient deck replacement, it is desirable to have a joint structure for PCa decks of road bridges and a method for forming the joint structure that can resolve the various issues mentioned above that arise with the half-section deck replacement method.

[0006] The present invention aims to provide a joint structure for PCa deck slabs of road bridges and a method for forming the same, which can effectively introduce prestress forces only to the vertical joints without causing parallel movement of the two PCa deck slabs that are connected to each other. [Means for solving the problem]

[0007] In order to achieve the above object, one aspect of the joint structure of a PCa deck slab of a road bridge according to the present invention is as follows: A joint structure of a PCa deck of a road bridge in which a first joint provided in a first PCa deck and a second joint provided in a second PCa deck are connected, The first joint is formed by a first shaft, a part of which is disposed inside a first insertion hole inside the first PCa deck slab, and another part of which protrudes laterally from an end face of the first joint, The second joint is A box is provided inside the second PCa floor slab, The box includes a rotatably mounted worm gear, a worm wheel rotated by the worm gear around its central axis of rotation, and a second shaft that is threaded into a bolt groove opened at the rotation center of the worm wheel, slides along the central axis of rotation, passes through a second insertion hole inside the second PCa deck, and protrudes laterally from the end face of the second joint. The first shaft and the second shaft are tensioned by being screwed into both ends of a threaded groove that passes through a coupler in the gap between the first joint end face and the second joint end face, and the gap is closed by a filler material.

[0008] According to this aspect, the first joint of the first PCa deck and the second joint of the second PCa deck that constitute the road bridge, which are connected to each other, are respectively equipped with a first shaft body and a second shaft body, and the first shaft body and the second shaft body are screwed into the coupler in the gap between the end faces of both decks and tensioned, so that prestress force can be effectively introduced only to the vertical joint without causing parallel movement of the two connected PCa decks. In this specification, PCa slabs also include PCaPC slabs. Filling material is filled into the gap between both end faces of the first PCa deck and the second PCa deck (the first joint end face and the second joint end face), and the coupler in the gap and parts of the first shaft body and second shaft body that protrude into the gap from both end faces are buried with the filling material to close the gap. After the gap is closed with filler material, the worm wheel is rotated and the second shaft is slid, causing the second shaft, which is in a tensioned position, to pull the coupler, tensioning the first shaft and introducing prestress force into both the second shaft and the first shaft.

[0009] In another aspect of the joint structure of the PCa deck of the road bridge according to the present invention, the first joint has the first shaft and a polygonal head fixed to one end of the first shaft, the first insertion hole has a straight hole having a diameter larger than that of the first shaft, and a polygonal hole communicating with the straight hole, having a contour complementary to that of the polygonal head, and having a depth greater than a thickness of the polygonal head, The polygonal head engages with the polygonal hole to form a rotation prevention mechanism that prevents the first shaft from rotating around its axis.

[0010] According to this aspect, the polygonal head of the first joint engages with the polygonal hole that constitutes the first insertion hole, forming an anti-rotation mechanism that prevents rotation of the first shaft around its axis.This means that the anti-rotation mechanism can prevent the first shaft from rotating when the second shaft is rotated by rotation of the worm wheel.This allows the coupler and first shaft to be maintained in a non-rotating position, allowing only the second shaft to rotate, and the second shaft to slide inside the second insertion hole while attracting the coupler, allowing prestress force to be introduced into both the first shaft and the second shaft. Furthermore, because the polygonal hole is deeper than the thickness of the polygonal head, there is play in the polygonal hole when the polygonal head is placed in the polygonal hole. Therefore, although the polygonal head engages with the polygonal hole in a non-rotatable manner, it can move in the depth direction of the polygonal hole. This allows for fine adjustment of the engagement between the threads (threads) on the coupler and the end of the shaft, making it easier to attach the end of the shaft to the coupler.

[0011] In another aspect of the joint structure of the PCa deck of the road bridge according to the present invention, The thread groove has a right-hand thread, One end of the first shaft is threaded into one end of the threaded groove, and one end of the second shaft is threaded into the other end of the threaded groove. When the first shaft and the second shaft are connected via the coupler, the coupler moves relative to the first shaft and the second shaft, and the first joint and the second shaft are tensioned by the sliding of the second shaft due to the rotation of the worm wheel.

[0012] According to this aspect, in the deck replacement construction, the first PCa deck and the second PCa deck are installed on the bridge girder with a gap between them, and when screwing one end of each of the first and second shaft bodies into both ends of the coupler's threading groove, the end of the first shaft body is first screwed into the threading groove at one end of the coupler, then the coupler is shifted to the side of the first shaft body, and then the second PCa deck is installed and the first and second shaft bodies are screwed together. This connection procedure eliminates the need to translate either or both of the first and second PCa decks when connecting the first and second shaft bodies via the coupler, achieving good joint connection construction.

[0013] In another aspect of the joint structure of the PCa deck of the road bridge according to the present invention, a first sheath extending into the gap is provided between the first insertion hole and the first shaft; a second sheath extending into the gap is provided between the second insertion hole and the second shaft; a third sheath is provided around the coupler in the gap and extends over both ends of the first sheath and the second sheath; The first sheath, the second sheath, and the third sheath are each filled with grout.

[0014] According to this aspect, a first sheath and a second sheath are provided between the first insertion hole and the first shaft, and between the second insertion hole and the second shaft, respectively, extending into the gap, and a third sheath is provided around the first shaft, the second shaft, and the coupler in the gap so as to wrap around the first sheath and the second sheath, and grout is filled inside these sheaths, thereby ensuring the corrosion resistance of the first shaft, the second shaft, and the coupler, while maintaining the initial prestress force introduction position.

[0015] In addition, one aspect of the method for forming a joint structure of a PCa deck slab of a road bridge according to the present invention is as follows: A method for forming a joint structure of a PCa deck that connects a first joint provided on a first PCa deck and a second joint provided on a second PCa deck, A process A includes preparing the first PCa deck and the second PCa deck, installing the first PCa deck on the girder in advance, and installing the second joint end surface of the second PCa deck on the girder in a position with a gap from the first joint end surface of the first PCa deck; and a step B of connecting the first joint and the second joint, In the step A, The first joint is formed by a first shaft, a part of which is disposed inside a first insertion hole inside the first PCa deck slab, and another part of which protrudes laterally from an end face of the first joint, The second joint is A box is provided inside the second PCa floor slab, The box includes a rotatably mounted worm gear, a worm wheel rotated by the worm gear around its central axis of rotation, and a second shaft that is threaded into a bolt groove opened at the rotation center of the worm wheel, slides along the central axis of rotation, passes through a second insertion hole inside the second PCa deck, and protrudes laterally from the end face of the second joint. In the step B, The first shaft and the second shaft are threaded into both ends of a threaded groove that passes through a coupler in the gap, the gap is closed with a filler, and the worm wheel is rotated to slide the second shaft, thereby tensioning the first shaft and the second shaft.

[0016] According to this aspect, the first joint of the first PCa deck slab and the second joint of the second PCa deck slab that make up the road bridge are each equipped with a first axle body and a second axle body, and the first axle body and the second axle body are screwed into a coupler in the gap between the end faces of both decks, and the first axle body and the second axle body are tensioned by rotating the worm wheel and sliding the second axle body, thereby making it possible to effectively introduce prestress force only into the vertical joint without causing parallel movement of the two connected PCa deck slabs.

[0017] Here, since this embodiment is a construction method that applies the half-section deck replacement method, in Step A, half of the existing, deteriorated deck (half of each of the up and down tracks) is removed to expose the bridge girders, and multiple first PCa decks are installed on top of the girders in the bridge axis direction. At this time, adjacent first PCa decks in the bridge axis direction are connected at their horizontal joints. After multiple first PCa decks are installed in the bridge axis direction over a certain section, the remaining half of the existing decks is removed to expose the end girders, and multiple second PCa decks are installed on top of the girders in the bridge axis direction. At this time, the second PCa decks are installed with a gap between them and the corresponding first PCa decks. Then, using this gap, both ends of the first and second axles are screwed into both ends of the threaded grooves that pass through the coupler. The gap is then closed with filler, and the second axle is slid as described above to tension the first and second axles. [Effects of the Invention]

[0018] According to the joint structure of the PCa deck of a road bridge and the method for forming it of the present invention, prestress force can be effectively introduced only to the vertical joint without causing parallel movement of the two PCa decks that are connected to each other. [Brief explanation of the drawings]

[0019] [Figure 1] This is an oblique view showing the state before the end of the first shaft body of the first PCa deck and the end of the second shaft body of the second PCa deck that constitute a road bridge are screwed into both ends of the coupler, and also shows step A of an example of a method for forming a joint structure of a PCa deck of a road bridge in an embodiment. [Figure 2] FIG. 1 is a perspective view of an example of a joint structure of a PCa deck slab of a road bridge according to an embodiment. [Figure 3] FIG. 10 is a perspective view showing an example of a first joint provided in the first PCa deck, with the embedded area visible. [Figure 4] FIG. 10 is a perspective view showing an example of a second joint provided in the second PCa deck, with the embedded area visible. [Figure 5]FIG. 10 is a process diagram illustrating step B of an example of a method for forming a joint structure of a PCa deck slab of a road bridge according to an embodiment. [Figure 6] 5, this is a process diagram illustrating the B process. [Figure 7] 6, this is a process diagram illustrating the B process. [Figure 8] 7, this is a process diagram illustrating the B process. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, a joint structure of a PCa deck slab of a road bridge and a method for forming the same will be described with reference to the accompanying drawings. Note that in this specification and the drawings, substantially identical components may be designated by the same reference numerals to avoid redundant explanation.

[0021] [Joint structure of PCa deck slab of road bridge according to embodiment and its forming method] Referring to Figures 1 to 8, an example of a joint structure for PCa decks and a method for forming the same according to an embodiment will be described. Here, Figure 1 is a perspective view showing the state before the end of the first shaft body of the first PCa deck and the end of the second shaft body of the second PCa deck constituting a road bridge are screwed to both ends of a coupler, and also shows step A of an example of a method for forming a joint structure for PCa decks of a road bridge according to an embodiment. Also, Figure 2 is a perspective view of an example of a joint structure for PCa decks of a road bridge according to an embodiment, Figure 3 is a perspective view showing an example of a first joint provided in the first PCa deck with a see-through embedded area, and Figure 4 is a perspective view showing an example of a second joint provided in the second PCa deck with a see-through embedded area. Furthermore, Figures 5 to 8 are process diagrams illustrating step B of an example of a method for forming a joint structure for PCa decks of a road bridge according to an embodiment.

[0022] The first PCa slab 10 and the second PCa slab 20 shown in FIG. 1 are constructed by dividing the aging reinforced concrete slabs (not shown) of the inbound and outbound lanes of an expressway in a direction perpendicular to the bridge axis, removing the existing reinforced concrete slabs in one of the divided areas to expose the bridge girders (not shown), and then installing multiple first PCa slabs 10 in the bridge axis direction. While FIG. 1 and other figures show one corresponding first PCa slab 10 and one corresponding second PCa slab 20, multiple combinations of these are installed in the bridge axis direction. During construction, multiple first PCa slabs 10 are installed first over a certain section in the bridge axis direction. Next, the existing reinforced concrete slabs in the other divided area are removed to expose the bridge girders (not shown), and then installing multiple second PCa slabs 20 in the bridge axis direction. Each second PCa slab 20 is installed with a gap G between the first PCa slab 10 and the second PCa slab 20.

[0023] Here, the joint structure of the horizontal joints of the first PCa decks 10 adjacent in the bridge axis direction is omitted from the illustration, but an appropriate joint structure is applied to connect multiple first PCa decks 10 in the bridge axis direction, and similarly, connect multiple second PCa decks 20 in the bridge axis direction.

[0024] From the first joint end face 11 of the first PCa deck 10, portions of multiple (five in the illustrated example) first shaft bodies 31 protrude laterally toward the second PCa deck 20. These first shaft bodies 31 form the first joint 30 together with a polygonal head 32 (see Figure 3).

[0025] A first sheath 50A is disposed around the first shaft 31, and part of it protrudes laterally from the first joint end surface 11 in the same manner as the first shaft 31.

[0026] Furthermore, the end opening of the grout injection hole 17 faces the position on the wide upper surface 12 of the first PCa deck 10 that corresponds to the first joint 30 .

[0027] On the other hand, portions of multiple (five in the illustrated example) second shaft bodies 41 protrude from the second joint end face 21 of the second PCa deck 20 toward the side of the first PCa deck 10. These second shaft bodies 41 form the second joint 40 together with a box 42, a worm gear 43, and a worm wheel 44 (all see Figure 4).

[0028] A second sheath 50B is disposed around the second shaft 41, and part of it protrudes laterally from the second joint end face 21 in the same manner as the second shaft 41.

[0029] The end opening of the grout injection hole 27 faces the wide upper surface 22 of the second PCa deck 20 at a position corresponding to the second joint 40. Furthermore, the end opening of the second insertion hole 26, which communicates with the worm gear 43, faces the wide upper surface 22.

[0030] The coupler 60 has a threaded groove 61 that passes through it, with one end 61a of the threaded groove 61 threadedly engaging the threaded portion 31b of the first shaft 31, and the other end 61b of the threaded groove 61 threadedly engaging the threaded portion 41b of the second shaft 41. For installation, for example, one end 61a of the threaded groove 61 of the coupler 60 is threadedly engaged with the threaded portion 31b of the first shaft 31 in the X1 direction, and then the coupler 60 is shifted toward the first shaft 31 and the second PCa deck 20 is installed. Next, the coupler 60 is moved in the X2 direction, and the threaded portion 41b of the second shaft 41 is threadedly engaged with the other end 61b of the threaded groove 61 of the coupler 60. As will be described below, the length of the first shaft 31 that extends from the first joint end face 11 can be adjusted, making it easy to attach both the ends of the first shaft 31 and the second shaft 41 to the coupler 60.

[0031] Furthermore, a third sheath 50C spanning both the ends of the first sheath 50A and the second sheath 50B is disposed around the coupler 60 in the gap G. Although only one third sheath 50C disposed around one coupler 60 is shown in FIG. 1, a third sheath 50C is disposed around all of the couplers 60.

[0032] The third sheath 50C in the illustrated example has a structure in which two half sheaths 52 are rotatably connected via hinges 51. After the coupler 60 is threaded onto both ends of the first shaft 31 and the second shaft 41, the third sheath 50C is moved in the X3 direction so as to surround the coupler 60. By closing the two half sheaths 52 in the X4 direction via the hinges 51, the coupler 60, the first shaft 31, and the second shaft 41 are completely surrounded by the three sheaths 50A, 50B, and 50C. Note that the interior of each sheath 50A, 50B, and 50C will be filled with grout in a subsequent process.

[0033] Prestress force is introduced into the first shaft 31 and the second shaft 41 by inserting a torque introducing tool T in the X5 direction through the second insertion hole 26 and rotating the torque introducing tool T by engaging the engagement key K at the tip of the torque introducing tool T with the key engagement groove 43b (see Figure 4) of the worm gear 43. The method of introducing prestress force will be described in detail below.

[0034] After the prestress force is introduced, grout is injected into the interior of each of the sheaths 50A, 50B, and 50C in the X6 direction through the grout injection holes 17 and 27, respectively.

[0035] As shown in Figure 2, prior to the introduction of prestressing force to the first shaft body 31 and the second shaft body 41, filler material 70 is filled into the gap G between the first joint end face 11 and the second joint end face 21, and after the filler material 70 hardens, prestressing force is introduced to the first shaft body 31 and the second shaft body 41, and grout is injected into the inside of each sheath 50A, 50B, 50C, thereby forming a joint structure 100 for the PCa deck of a road bridge. This joint structure 100 is a vertical joint extending in the bridge axis direction.

[0036] The grout injection hole 17 facing the wide upper surface 12 of the first PCa deck 10, the grout injection hole 27 facing the wide upper surface 22 of the second PCa deck 20, and the second insertion hole 26B are all blocked with grout 80.

[0037] As shown in Figure 3, a first insertion hole 15 is opened inside the first PCa deck 10, and its end faces the first joint end face 11. The first insertion hole 15 has a straight hole 15a and a polygonal hole 15b that communicates with the straight hole 15a.

[0038] A first sheath 50A is inserted into the straight hole 15a, and a part of it protrudes laterally from the first joint end face 11. A grout injection hole 17 facing the wide upper surface 12 penetrates a part of the first sheath 50A and faces its inner wall.

[0039] The first joint 30 has a first shaft 31 and a polygonal head 32 (a hexagonal head in the illustrated example) fixed to one end 31a of the first shaft 31. Here, the first shaft 31 and the polygonal head 32 may be manufactured separately and fixed together by adhesive, welding, or the like, or may be manufactured as a single unit by casting or the like.

[0040] The straight hole 15a of the first insertion hole 15 has a larger diameter than the first shaft 31, and the polygonal hole 15b of the first insertion hole 15 has a shape in front view that has a contour complementary to the polygonal head 32. With this configuration, the polygonal head 32 engages with the polygonal hole 15b, and the first joint 30 is prevented from rotating about its longitudinal axis by the first insertion hole 15, and the polygonal hole 15b and the polygonal head 32 form an anti-rotation mechanism.

[0041] The depth t2 of the polygonal hole 15b is set deeper than the thickness t1 of the polygonal head 32. The first joint 30 is able to slide in the X5 direction toward the second PCa deck 20 by the difference Δt (play) between the two. This allows the end of the first shaft 31 to be attached to the coupler 60 first, and then the end of the second shaft 41 can be easily attached to the coupler 60 by adjusting the length of the first shaft 31 that extends from the first joint end face 11 as desired. Here, the other end 31b of the first shaft 31 is provided with a thread that screws into the threading groove 61 of the coupler 60.

[0042] As shown in Figure 4, a box 42 that forms the second joint 40 is buried inside the second PCa deck 20. A rotatably mounted worm gear 43 and a worm wheel 44 that is rotated around its central axis of rotation L by the worm gear 43 are disposed inside the box 42. A gear 43c of the worm gear 43 and a gear 44c of the worm wheel 44 mesh with each other, so that the rotation of the worm gear 43 can be transmitted to the worm wheel 44.

[0043] A bolt groove 44a is formed in the rotation center of the worm wheel 44, and one end 41a of the second shaft 41 is screwed into the bolt groove 44a. When the one end 41a of the second shaft 41 is screwed into the bolt groove 44a, the bolt groove 44a has an excess length (play), which allows the one end 41a of the second shaft 41 to slide. Specifically, as will be explained below, when the second shaft 41 slides, a prestress force is introduced to both the second shaft 41 and the first shaft 31, and the second shaft 41 is allowed to slide when this prestress force is introduced.

[0044] The second PCa deck 20 has a second insertion hole 26B facing the wide upper surface 22 at a position corresponding to the worm gear 43 inside the box 42. Furthermore, the second PCa deck 20 has a separate second insertion hole 26A facing the second joint end face 21, and a second sheath 50B is disposed in the second insertion hole 26A, with a portion of the second sheath 50B extending laterally from the second joint end face 21. The grout injection hole 27 facing the wide upper surface 22 penetrates a portion of the second sheath 50B and faces its inner wall.

[0045] The second shaft 41, one end 41a of which is threadedly engaged with the bolt groove 44a of the worm wheel 44, is inserted into the second insertion hole 26A, and a portion of which protrudes laterally from the second joint end face 21. The other end 41b of the second shaft 41 is provided with a thread that threads into the threading groove 61 of the coupler 60.

[0046] An engagement groove 43a is provided at one end of the worm gear 43, and a key engagement groove 43b is provided in the engagement groove 43a. A torque introducing tool T (see FIG. 1) is inserted into the engagement groove 43a via the second insertion hole 26B, and an engagement key K at one end of the torque introducing tool T is engaged with the key engagement groove 43b. Rotation of the torque introducing tool T rotates the worm gear 43 in the Y1 direction. The rotation of the worm gear 43 rotates the worm wheel 44 in the Y2 direction about its rotation center axis L, and the second shaft 41 rotates in the Y3 direction in synchronization with the rotation of the worm wheel 44.

[0047] The rotation of the second shaft 41 due to the rotation of the worm wheel 44 is performed when a prestress force is introduced into both the first shaft 31 and the second shaft 41. When introducing this prestress force, the thread 31b on the end of the first shaft 31 and the thread 41b on the end of the second shaft 41 are threadedly engaged with one end 61a and the other end 61b of the thread groove 61 of the coupler 60, respectively.

[0048] Here, the screw groove 61 is provided with a right-hand thread, and the threads 31 b and 41 b of the first shaft 31 and the second shaft 41 are threaded in a form that allows them to be screwed into the screw groove 61 .

[0049] On the other hand, as described above, the first shaft 31 is prevented from rotating about its axis by the rotation prevention mechanism formed by the polygonal hole 15b and the polygonal head 32. With this configuration, when the second shaft 41 is rotated in the Y3 direction in synchronization with the rotation of the worm wheel 44, the rotation of the first shaft 31 and the coupler 60 is restricted, so only the second shaft 41 rotates, and the second shaft 41 slides inside the second insertion hole 26A in the Y4 direction in synchronization with the rotation, attracting the coupler 60 and the first shaft 31.

[0050] The pulling action of the second shaft body 41 on the coupler 60 and the first shaft body 31 introduces prestress force to both the first shaft body 31 and the second shaft body 41. Moreover, with this method of introducing prestress force, prestress force is introduced only to the first joint 30 and the second joint 40, so there is no risk of excessive prestress force being applied to general parts other than the vertical joints in the first PCa deck 10 and the second PCa deck 20, resulting in severe compressive stress.

[0051] According to the joint structure 100, it is possible to effectively introduce prestress force only into the vertical joint without causing parallel movement of the two PCa deck slabs 10, 20 that are connected to each other.

[0052] Next, an example of a method for forming a joint structure of a PCa deck slab of a road bridge according to an embodiment will be described with reference to Fig. 1 and Figs. 5 to 8.

[0053] As shown in Figure 1, an aged RC slab (not shown) is divided in a direction perpendicular to the bridge axis, and the existing RC slab in one of the divided areas is removed to expose the bridge girders (not shown), and multiple first PCa slabs 10 are installed in the bridge axis direction. Next, the existing RC slab in the other divided area is removed to expose the bridge girders (not shown), and multiple second PCa slabs 20 are installed in the bridge axis direction. At this time, as shown in Figure 5, each second PCa slab 20 is installed with a gap G between the first PCa slab 10 and the second PCa slab 20 (this is step A).

[0054] As shown in Figure 5, a portion of the first shaft 31 forming the first joint 30 protrudes laterally from the first joint end face 11 of the first PCa deck 10, and a portion of the second shaft 41 forming the second joint 40 protrudes laterally from the second joint end face 21 of the second PCa deck 20. First, the thread 31b of the first shaft 31 is screwed into one end 61a of the screw groove 61 of the coupler 60, and then the thread 41b of the second shaft 41 is screwed into the other end 61b of the screw groove 61.

[0055] At this time, the first shaft 31 is slid as desired in the X5 direction to adjust the length of overhang from the first joint end face 11, and the coupler 60 is turned to move it in the X6 direction toward the threaded portion 41b, thereby threading the threaded portion 41b into the threading groove 61. Here, a portion of the first sheath 50A disposed between the first insertion hole 15 and the first shaft 31 overhangs into the gap G, and a portion of the second sheath 50B disposed between the second insertion hole 26A and the second shaft 41 also overhangs into the gap G.

[0056] Next, as shown in Figure 6, a third sheath 50C is placed around the coupler 60 in the gap G, spanning the protruding portions of both the first sheath 50A and the second sheath 50B, and the first sheath 50A, the second sheath 50B, and the third sheath 50C seal the first shaft 31, the second shaft 41, and the coupler 60 from the gap G. After that, the gap G is filled with a filler material 70 to fill the gap G.

[0057] Next, as shown in Figure 7, the tip of the torque introducing tool T is engaged with the worm gear 43, and the torque introducing tool T is used to rotate the worm gear 43 in the Y1 direction, rotate the worm wheel 44 in the Y2 direction around its rotation center axis, and rotate the second shaft body 41 in the Y3 direction.

[0058] Due to the anti-rotation mechanism formed by the polygonal hole 15b and polygonal head 32, the second shaft 41 rotates and slides in the Y4 direction relative to the first shaft 31 and coupler 60, which do not rotate. As the second shaft 41 slides in the Y4 direction, the coupler 60 and the entire first shaft 31 are pulled in the Y5 direction toward the second PCa deck 20, and the desired prestress force is introduced into both the first shaft 31 and the second shaft 41.

[0059] After the desired prestress force is introduced into the first shaft 31 and the second shaft 41, as shown in Fig. 8, grout 80 is injected into the inside of the first sheath 50A, the second sheath 50B, and the third sheath 50C through the grout injection holes 17 and 27. The grout 80 blocks the inside of each sheath 50A, 50B, and 50C as well as the inside of the box 42 and the inside of the grout injection holes 17 and 27, thereby forming a joint structure 100 (this is step B).

[0060] According to the method of forming the joint structure shown in the figure, while applying the half-section deck replacement method, prestress force can be effectively introduced only to the vertical joint without moving both of the two PCa decks 10, 20 that are connected to each other in parallel.

[0061] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0062] 10: 1st PCa floor slab (PCa floor slab) 11: First joint end face 12: Wide top 13: Horizontal joint end face 15: First insertion hole 15a: Straight hole 15b: Polygonal hole 17: Grout injection hole 20: 2nd PCa floor slab (PCa floor slab) 21: Second joint end face 22: Wide top 23: Horizontal joint end face 26, 26A, 26B: Second insertion hole 27: Grout injection hole 30: First joint 31: First axis 31a: One end (end) 31b: Threaded (other end) 32: Polygonal head 40: Second joint 41: Second axis 41a: One end (end) 41b: Threaded (other end) 42: Box 43: Worm gear 43a: Engagement groove 43b: Key engagement groove 43c: Gear 44: Worm wheel 44a: Bolt groove 44c: Gear 50A: First sheath (sheath) 50B: Second sheath (sheath) 50C: Third sheath (sheath) 51: Hinge 52: Half-split sheath 60: Coupler 61: Right-hand thread (threaded groove) 61a: one end 61b: other end 70: Filling material 80:Grout 100: Joint structure of PCa deck of road bridge (joint structure of PCa deck, joint structure) G: Gap T: Torque introduction tool K: Engagement key L: Rotation axis

Claims

1. A joint structure of a PCa deck of a road bridge, in which a first joint provided on a first PCa deck and a second joint provided on a second PCa deck are connected, The first joint is formed by a first shaft, a part of the first shaft is disposed inside a first insertion hole inside the first PCa deck slab, and the other part protrudes laterally from an end face of the first joint, The second joint is A box is provided inside the second PCa floor slab, The box includes a rotatably mounted worm gear, a worm wheel rotated by the worm gear around its central axis of rotation, and a second shaft threadedly engaged with a bolt groove formed at the rotation center of the worm wheel, sliding along the central axis of rotation, passing through a second insertion hole in the second PCa deck, and projecting laterally from the end face of the second joint. A joint structure for a PCa deck slab of a road bridge, characterized in that the first shaft body and the second shaft body are tensioned by being screwed into both ends of a threaded groove that passes through a coupler in the gap between the first joint end face and the second joint end face, and the gap is blocked by a filler material.

2. the first joint has the first shaft and a polygonal head fixed to one end of the first shaft, the first insertion hole has a straight hole having a diameter larger than that of the first shaft, and a polygonal hole communicating with the straight hole, having a contour complementary to that of the polygonal head, and having a depth greater than a thickness of the polygonal head, 2. A joint structure for a PCa deck slab of a road bridge as described in claim 1, characterized in that the polygonal head engages with the polygonal hole to form an anti-rotation mechanism that prevents the first shaft from rotating around its axis.

3. The thread groove has a right-hand thread, 3. A joint structure for a PCa deck slab of a road bridge as described in claim 1 or 2, characterized in that one end of the first shaft body is threaded into one end of the threaded groove, and one end of the second shaft body is threaded into the other end of the threaded groove, and when the first shaft body and the second shaft body are connected via the coupler, the coupler moves relative to the first shaft body and the second shaft body, and the sliding of the second shaft body due to the rotation of the worm wheel tensions the first shaft body and the second shaft body via the coupler.

4. a first sheath extending into the gap is provided between the first insertion hole and the first shaft; a second sheath extending into the gap is provided between the second insertion hole and the second shaft; a third sheath is provided around the coupler in the gap and extends over both ends of the first sheath and the second sheath; 3. A joint structure for PCa deck slabs of a road bridge according to claim 1 or 2, characterized in that the first sheath, the second sheath and the third sheath are filled with grout.

5. A method for forming a joint structure of a PCa deck of a road bridge, which connects a first joint provided on a first PCa deck and a second joint provided on a second PCa deck, A process A includes preparing the first PCa deck and the second PCa deck, installing the first PCa deck on the girder in advance, and installing the second joint end surface of the second PCa deck on the girder in a position with a gap from the first joint end surface of the first PCa deck; and a step B of connecting the first joint and the second joint, In the step A, The first joint is formed by a first shaft, a part of the first shaft is disposed inside a first insertion hole inside the first PCa deck slab, and another part protrudes laterally from an end face of the first joint, The second joint is A box is provided inside the second PCa floor slab, The box includes a rotatably mounted worm gear, a worm wheel rotated by the worm gear around its central axis of rotation, and a second shaft threadedly engaged with a bolt groove formed at the rotation center of the worm wheel, sliding along the central axis of rotation, passing through a second insertion hole in the second PCa deck, and projecting laterally from the end face of the second joint. In the step B, A method for forming a joint structure of a PCa deck slab of a road bridge, characterized in that the first shaft body and the second shaft body are screwed into both ends of a threaded groove that passes through a coupler in the gap, the gap is blocked with filler material, and the worm wheel is rotated to slide the second shaft body, thereby tensioning the first shaft body and the second shaft body via the coupler.

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