Joint structure of concrete precast floor slab

Abstract

To make a shear key function in a vertical joint part, and to simplify filling work of a joint part, even when adopting a joint structure having a female joint and a male joint engaging with this female joint in a bridge axial directional joint structure.SOLUTION: In the joint structure in the direction perpendicular to the bridge, a recessed portion 20 in which an intermediate portion in a thickness direction is recessed in a recessed shape is formed in each of joint end surfaces of a side 1Aa and a side 1Ba of the concrete precast floor slabs on both sides with a joint portion as a boundary. The cross-sectional shape of a part where the recessed parts 20 face each other is formed in an elliptic shape long in the vertical direction in a state where the joint end faces of the concrete precast floor slabs adjacent in the bridge axis right angle direction face each other.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a joint structure that is compatible with construction methods such as half-section deck replacement, which are used to join adjacent concrete precast decks perpendicular to the bridge axis, in which horizontal movement of the decks is difficult after installation. [Background technology]

[0002] When carrying out renovation work on aging viaducts and bridges on expressways and other roads, it is necessary not only to update them to more durable structures, but also to use construction methods that reduce the social impact of traffic restrictions and minimize the disruption to user convenience.

[0003] The applicant has proposed a joint structure, as disclosed in Patent Documents 1 to 4 below, for the purposes of reducing the convenience for users by shortening the construction period for deck replacement work, reducing the amount of work required, and improving the safety of construction, in which female joints with a grooved cross section in plan view are embedded with their vertical grooves facing outward at a predetermined horizontal interval on the joint end surface of the concrete precast deck on one side of the joint portion, and male joints are embedded at a predetermined horizontal interval on the joint end surface of the concrete precast deck on the other side of the joint portion, with their tips protruding outward and with fixing parts at the tips that can engage with the female joints, and the female joint of the concrete precast deck on one side engages with the male joint of the concrete precast deck on the other side, thereby joining the concrete precast decks together.

[0004] In conventional deck replacement work, for example, in the case of a road with two lanes each on the inbound and outbound lanes, as shown in Figure 14, the work involves completely closing the road on one of the inbound and outbound lanes where the deck is to be replaced, and allowing two-way traffic on the other lane, as shown in Figure 14(A), and replacing the entire cross section of one of the lanes with a single precast deck.

[0005] However, this construction method requires large-scale traffic restrictions to be implemented in order to restrict two-way traffic at the construction site, which could lead to an increase in traffic congestion and traffic accidents.

[0006] In order to solve these problems, Patent Documents 5 and 6 below propose a construction method (the so-called half-section deck replacement method) in which the route on which the deck replacement is to be performed is divided into a primary construction section and a secondary construction section (driving lane and passing lane), the driving lane is left in a state where it can be used as a road, the adjacent passing lane is replaced, and after the replaced passing lane is used as a road, the driving lane is replaced. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-39292 [Patent Document 2] Japanese Patent Publication No. 2020-176372 [Patent Document 3] Japanese Patent Publication No. 2020-193481 [Patent Document 4] Patent Publication No. 2021-31902 [Patent Document 5] Patent No. 6323776 [Patent Document 6] Patent No. 6150138 Summary of the Invention [Problem to be solved by the invention]

[0008] In this type of half-section deck replacement method, in order to counteract the shear force caused by shear stress generated between the precast deck slab on the driving lane side and the adjacent precast deck slab on the passing lane side, it is common to provide a concave-convex shear key at the joint (vertical joint) as shown in Figure 15, which consists of a convex portion 51 provided on the end face of the joint of one precast deck slab 50 and a concave portion 53 with which the convex portion 51 can engage, provided on the end face of the joint of the other precast deck slab 52.

[0009] The construction procedure for precast decks with shear keys of the above-mentioned structure in the vertical joints was to lift the precast deck 52 to be erected later with a crane and place it next to the precast deck 51 that had been erected earlier, and then move the precast deck 52 horizontally in a direction perpendicular to the bridge axis to engage the convex portion 51 and concave portion 53 of the shear key.

[0010] This type of construction method is possible when a conventional loop joint, as shown in Figure 15, is used as the joint structure for the precast deck in the bridge axis direction, because after the precast deck slab 52 to be erected later is lowered, there is room for horizontal movement perpendicular to the bridge axis by at least the height of the shear key irregularities.

[0011] However, when the joint structure for concrete precast deck slabs in the bridge axis direction, which engages a female joint and a male joint as disclosed in Patent Documents 1 to 4, is adopted, there is no margin between the female joint and the male joint to allow horizontal movement perpendicular to the bridge axis, and problems arise such as interference from the uneven shear keys, making it impossible to drop the precast deck slab to be erected later. One possible solution is to widen the width of the vertical joints to prevent interference from the shear keys, but this creates problems such as complication of the filling work for filling the vertical joints, an increase in the amount of filling, and a decline in quality.

[0012] Therefore, the main objective of the present invention is to provide a joint structure for concrete precast deck slabs in the direction perpendicular to the bridge axis, which allows shear keys to function in the vertical joints and simplifies the work of filling the joints, even when a joint structure equipped with a female joint and a male joint that engages with it is used for the joint structure in the bridge axis direction between concrete precast deck slabs. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention according to claim 1 provides a bridge axis direction joint structure for joining adjacent concrete precast deck slabs in the bridge axis direction, and a bridge axis perpendicular direction joint structure for joining adjacent concrete precast deck slabs in the direction perpendicular to the bridge axis, The bridge axis direction joint structure is a joint end surface of the concrete precast deck slab on one side of the joint part, and female joints with a grooved cross section in a plan view are embedded at a predetermined interval in the horizontal direction with the vertical groove facing outward, On the other side of the joint, at a predetermined interval in the horizontal direction, male joints are embedded at the joint end surface of the concrete precast deck, with their tip ends protruding from the joint end surface of the concrete precast deck, and these male joints have fixing portions at their tips that can engage with the female joints. The female joint of one concrete precast deck slab is engaged with the male joint of the other concrete precast deck slab, joining the concrete precast decks together, and grout is filled in the internal space of the female joint, the space around the female joint, and the gap between the one concrete precast deck slab and the other concrete precast deck slab. The bridge axis perpendicular joint structure has a recess formed on the joint end surfaces of the concrete precast deck slabs on both sides of the joint section, with the middle part in the thickness direction recessed, A joint structure for concrete precast decks is provided, characterized in that the joint end faces of adjacent concrete precast decks facing each other in a direction perpendicular to the bridge axis are positioned opposite each other, and grout material is filled in these gaps, including the recesses.

[0014] In the invention described in claim 1 above, when a joint structure equipped with a female joint and a male joint that engages with it is adopted as the bridge axis direction joint structure for joining adjacent concrete precast deck slabs in the bridge axis direction, the bridge axis perpendicular joint structure for joining adjacent concrete precast deck slabs in the direction perpendicular to the bridge axis has a structure in which a recess is formed by recessing the middle part in the thickness direction on each of the joint end surfaces of the concrete precast deck slabs on both sides of the joint part, so that the shear key does not interfere when dropping in the precast deck slab to be erected later, and when adjacent concrete precast deck slabs in the direction perpendicular to the bridge axis are placed opposite each other, the recesses are arranged opposite each other, and grout material is filled in these gaps including the recesses, so that the shear key can function in the vertical joint, and because the groove width at the upper and lower ends of the vertical joint remains the same as before, there is no need to make the filling work complicated.

[0015] As a second aspect of the present invention, in order to introduce tension between adjacent concrete precast deck slabs in the direction perpendicular to the bridge axis, a plurality of PC steel members are provided that penetrate the joint structure in the direction perpendicular to the bridge axis, extend across the entire width in the direction perpendicular to the bridge axis, and are inserted into sheaths that are arranged at intervals in the direction of the bridge axis, The sheath is composed of a one-side sheath arranged with its edge facing the joint end surface of one of the adjacent concrete precast decks in the direction perpendicular to the bridge axis, a second-side sheath arranged with its edge facing the joint end surface of the other concrete precast deck, and a core sheath inserted into either the one-side sheath or the other-side sheath before the subsequent erection of the concrete precast deck. A joint structure for concrete precast deck slabs as described in claim 1 is provided, in which concrete precast deck slabs are placed adjacent to each other in the direction perpendicular to the bridge axis, and by pulling out the core sheath and inserting its tip into the sheath on the opposite side, the core sheath is connected between the sheath on one side and the sheath on the other side, and the sheath into which the PC steel is inserted is positioned across the entire width in the direction perpendicular to the bridge axis.

[0016] The invention described in claim 2 specifically shows a means for installing prestressing tendons inserted into sheaths extending across the entire width of the bridge to introduce tension between adjacent concrete precast deck slabs in the direction perpendicular to the bridge axis, by passing the sheaths through the joint structure in the direction perpendicular to the bridge axis. Specifically, one sheath is embedded in one of the concrete precast deck slabs and the other sheath is embedded in the other concrete precast deck slab, and a core sheath is inserted into either the one sheath or the other sheath. With the concrete precast deck slabs adjacent to each other in the direction perpendicular to the bridge axis, the core sheath is pulled out and its tip is inserted into the sheath on the other side, connecting the core sheath between the one sheath and the other sheath, so that the sheath inserting the prestressing tendons is arranged across the entire width of the bridge in the direction perpendicular to the bridge axis.

[0017] As the present invention related to claim 3, there is provided a joint structure for a concrete precast deck as described in claim 2, in which a joint widening portion is provided from the top surface of the concrete precast deck toward the positioning portion of the core sheath in order to pull out the core sheath.

[0018] In the invention described in claim 3 above, when concrete precast deck slabs are placed adjacent to each other in a direction perpendicular to the bridge axis, a joint widening portion is provided into which a hand or tool can be inserted to pull out the core sheath inserted into either the one-side sheath or the other-side sheath.

[0019] The present invention as claimed in claim 4 provides a joint structure for concrete precast decks as described in claim 1, in which when the joint end faces of adjacent concrete precast decks in the direction perpendicular to the bridge axis are opposed to each other, the cross-sectional shape of the portion where the recesses face each other is an elliptical shape that is elongated in the vertical direction.

[0020] In the invention described in claim 4 above, the cross-sectional shape of the part where the recesses that serve as shear keys face each other is formed as an ellipse that is long in the vertical direction, so that when grout material is filled in the joint, air can easily escape, simplifying the work of filling the joint. [Effects of the Invention]

[0021] As explained in detail above, according to the present invention, even when a joint structure equipped with a female joint and a male joint that engages with it is adopted as a joint structure in the bridge axis direction between concrete precast deck slabs, it is possible to make the shear key function in the vertical joint section and to simplify the work of filling the joint section. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a plan view showing the bridge axis direction joints 2 and the bridge axis transverse direction joints 3 of the concrete precast deck slabs 1Aa, 1Ab, 1Ba, and 1Bb. [Figure 2] FIG. 2 is an enlarged plan view of the bridge axis direction joint 2. [Figure 3] FIG. 3 is a view taken along the line III-III in FIG. 2. [Figure 4] 1 shows a female joint 4, where (A) is a front view, (B) is a plan view, (C) is a left side view, (D) is a right side view, and (E) is an E-E cross-sectional view of (B). [Figure 5] FIG. 10 is a perspective view of the deck showing the male joint 7. [Figure 6] 1 shows a male joint 7, in which (A) is a front view, (B) is a plan view, (C) is a left side view, and (D) is a right side view. [Figure 7] 10A to 10C are diagrams showing the joining procedure for the bridge axis direction joint 2. [Figure 8] FIG. 8 is a view taken along the line VIII-VIII in FIG. [Figure 9] FIG. 9 is a view taken along the line IX-IX in FIG. [Figure 10] This is an oblique view of the precast deck slab seen from the joint end face side of the joint part 3 perpendicular to the bridge axis. [Figure 11]This is an oblique view of the precast deck slab seen from the opposite side of the joint end surface of the joint 3 perpendicular to the bridge axis. [Figure 12] This is a modified example of the recess 20. [Figure 13] 10 shows procedural diagrams (A) to (D) of the joining procedure for the joint 3 perpendicular to the bridge axis. [Figure 14] This is an illustration of traffic regulations. [Figure 15] FIG. 10 is a perspective view showing the engagement method in the case of a conventional loop joint. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0024] As shown in Figure 1, the joint structure of the present invention is a mechanical joint structure consisting of bridge axis direction joint parts 2 for joining adjacent concrete precast deck slabs (hereinafter simply referred to as precast deck slabs) 1Aa, 1Ab together and 1Ba, 1Bb together in the bridge axis direction, and bridge axis perpendicular direction joint parts 3 for joining adjacent precast deck slabs 1Aa, 1Ba together and 1Ab, 1Bb together in the direction perpendicular to the bridge axis.

[0025] (Structure of bridge axis joint 2) First, we will explain in detail the bridge axis direction joint 2. The joint structures for joining precast deck slabs adjacent in the bridge axis direction described in the above Patent Documents 1 to 4 can be used as this bridge axis direction joint 2. As an example, we will explain the bridge axis direction joint described in the above Patent Document 4.

[0026] As shown in Figure 1, the bridge axis direction joint 2 is formed by embedding female joints 4 with groove-shaped cross sections in a plan view at a predetermined interval horizontally on the joint end surfaces of the precast deck slabs 1Aa and 1Ba on one side of the joint 2, with their vertical grooves 5 facing outward. On the other hand, male joints 7 are embedded at a predetermined interval horizontally on the joint end surfaces of the precast deck slabs 1Ab and 1Bb on the other side of the joint 2, with their tips protruding from the joint end surfaces of the precast deck slabs 1Ab and 1Bb, and with anchoring parts 6 at their tips that can engage with the female joints 4. As shown in Figures 2 and 3, the female joints 4 of the precast deck slabs 1Aa, 1Ba on one side are engaged with the male joints 7 of the precast deck slabs 1Ab, 1Bb on the other side, joining the precast deck slabs 1Aa, 1Ab together and 1Ba, 1Bb together, and grout material 8 is filled in the internal space of the female joints 4, the space around the female joints 4, and the gaps (horizontal joints MH) between the precast deck slabs 1Aa, 1Ba on one side and the precast deck slabs 1Ab, 1Bb on the other side.

[0027] This will be explained in more detail below.

[0028] First, the female joints 4 provided on the precast floor slabs 1Aa, 1Ba on one side will be described in detail with reference to FIGS.

[0029] As shown in detail in Figure 4, the female joint 4 is a metal member composed of a groove-type engaging portion 9 having a groove-shaped cross section in a plan view, with a longitudinal groove 5 formed on its front end face, and a female joint anchor portion 10 extending rearward from the rear end face of the groove-type engaging portion 9 that faces the front end face on which the longitudinal groove 5 is formed.

[0030] The groove-type engaging portion 9 has a box-like shape with an open top and the vertical groove 5 formed on the front end surface, communicating with the open top, along the vertical direction. The groove-type engaging portion 9 may have an open bottom as well as an open top. However, as shown in FIG. 4(E), it is preferable to provide a bottom plate that closes the bottom, giving it a groove-type cross section with a bottom. This prevents the groove-type engaging portion 9 from opening to both sides (opening in the direction that would widen the vertical groove 5). In addition, an opening (not shown) for communication with the filler may be provided in the center of the bottom surface of the groove-type engaging portion 9.

[0031] The groove-shaped engaging portion 9 is formed in a vertically elongated shape. That is, the height H in the front view shown in FIG. 8(A) is greater than the width B and depth C in the plan view shown in FIG. 8(B). The height H of the groove-shaped engaging portion 9 is preferably 1.2 to 3 times, and more preferably 1.5 to 2 times, the width B or depth C. The height H of the groove-shaped engaging portion 9 is preferably 50 to 90%, and more preferably 60 to 80%, of the thickness of the precast floor slabs 1Aa and 1Ba, and is preferably located at approximately the center of the thickness of the precast floor slabs 1Aa and 1Ba.

[0032] As shown in Figure 4, the width dimension B of the groove-type engagement portion 9 is approximately 80 to 150 mm, preferably 100 to 130 mm, and the depth dimension C is preferably equal to or smaller than the width dimension B, approximately 60 to 120 mm, preferably 70 to 100 mm.

[0033] As shown in Figure 4(D), the width S of the longitudinal groove 5 formed in the groove-type engaging portion 9 is 20 to 60 mm, preferably 30 to 50 mm, and is 110 to 220%, preferably 120 to 200%, of the thickness of the male joint anchor portion 11 constituting the male joint 7 described below. This ratio to the thickness of the male joint anchor portion 11 is desirably set within an appropriate numerical range, as it is strictly related to the tolerance for manufacturing or installation errors. Furthermore, if this ratio is too large, the engagement with the fixing portion 6 of the male joint 7 will be reduced, reducing the joint strength, so it is desirably formed at a specified ratio.

[0034] The vertical groove 5 may be formed vertically from the upper edge to the lower edge of the groove-type engaging portion 9. However, as shown in FIG. 4, it is preferable to form a U-shaped vertical groove extending from the upper edge to the middle of the vertical groove 5. By connecting the lower end of the U-shaped vertical groove in the width direction, it is possible to prevent the vertical groove 5 from opening to both sides. The vertical groove 5 may be formed with a substantially uniform width along its entire length, as shown in FIG. 4(D), or, although not shown, may have a sloped portion at the upper end of the vertical groove 5 whose width gradually increases toward the upper end. By providing the sloped portion at the upper end of the vertical groove 5, the protruding male joint anchor portion 11 (see FIG. 5) can be more easily inserted into the vertical groove 5 when the other precast deck slab 1Ab, 1Bb is dropped in from above.

[0035] As shown in Figures 2 and 3, when the precast deck slabs 1Aa, 1Ba on one side are joined to the precast deck slabs 1Ab, 1Bb on the other side, the male joint anchor portion 11 protruding from the joint end surface of the precast deck slabs 1Ab, 1Bb on the other side is inserted into the vertical groove 5, and the fixing portion 6 provided at the tip of the male joint anchor portion 11 is inserted into the internal space of the groove-type engagement portion 9.

[0036] The female joint anchor portion 10 extending rearward from the groove-type engaging portion 9 is preferably formed in a flat plate shape along a vertical plane, as shown in Figure 4. The female joint anchor portion 10 extends rearward a predetermined length from the center of the rear end face that faces the front end face on which the longitudinal groove 5 of the groove-type engaging portion 9 is formed. The rear end of the female joint anchor portion 10 is provided with rear end fixing portions 10a that protrude on both sides and have a flat plate shape along a plane parallel to the joining end face.

[0037] The height dimension of the female joint anchor portion 10 is preferably formed to have a substantially constant width over the entire length, and is 30 to 100% of the height H of the groove-type engaging portion 9, preferably 40 to 60%.

[0038] The female joint anchor portion 10 is preferably positioned independently of the rebars of the precast deck slabs 1Aa and 1Ba. In other words, the stress in the bridge axis direction acting on the female joint 4 is substantially supported only by the female joint anchor portion 10, and does not act on the bridge axis direction rebars. In this way, by providing the female joint anchor portion 10 independently of the bridge axis direction rebars, design freedom can be improved in terms of the placement of the bridge axis direction rebars, and while it is difficult to apply this to curved or inclined rebars when connecting to the bridge axis direction rebars, when placed independently of the rebars, it can be applied as long as it does not interfere with adjacent rebars.

[0039] Furthermore, the length of the female joint anchor portion 10 in the bridge axis direction should be 1.2 to 3 times, and preferably 1.5 to 2 times, the depth C of the groove-type engaging portion 9, and it is not necessary to provide it over the entire length of the precast deck slabs 1Aa, 1Ba. As such, because the length of the female joint anchor portion 10 is short and it is not connected to the reinforcing bars in the bridge axis direction, handling during fabrication of the precast deck slabs 1Aa, 1Ba is easy and handleable.

[0040] To position the female joint 4 on one side of the precast slabs 1Aa, 1Ba, as shown in Figures 2 and 3, the groove-shaped engaging portion 9 is embedded with the opening on its upper surface facing outward from the top surface and the vertical groove 5 facing outward from the joint end surface, and the female joint anchor portion 10 is positioned in a state where it is completely embedded inside the concrete of the precast slabs 1Aa, 1Ba.

[0041] The female joint 4 is preferably manufactured by a mold casting method, which allows for greater freedom in shape. This allows the groove-shaped engaging portion 9 and female joint anchor portion 10 to be formed integrally, and by integrating the joint portion body and the anchor portion without welding, crimping, or bolting, the structure is stabilized and concerns about fatigue damage are eliminated, resulting in a high-strength joint structure and facilitating the manufacture of precast deck slabs 1Aa and 1Ba. Furthermore, manufacturing using a mold casting method increases the bond strength with concrete, improving the fixation of the female joint 4.

[0042] Next, the male joints 7 provided on the precast deck slabs 1Ab, 1Bb on the other side adjacent to each other in the bridge axis direction will be described with reference to FIGS. 2, 3, 5 and 6. FIG.

[0043] As shown in detail in Figures 5 and 6, the male joint 7 is a metal member consisting of a male joint anchor portion 11 whose tip end protrudes from the joint end surface of the precast deck slabs 1Ab, 1Bb and whose base end is embedded in concrete, and a fixing portion 6 which is provided at the protruding tip of this male joint anchor portion 11 and can be inserted into the groove-type engaging portion 9 of the female joint 4.

[0044] The fixing portion 6 is formed by wide portions that protrude on both sides from the male joint anchor portion 11 in a plan view as shown in Figure 6(A), and is formed so that it can be inserted downward from the top opening into the internal space within the groove-type engagement portion 9 of the female joint 4.

[0045] The anchoring portion 6 is formed in a vertically elongated shape. That is, the height K of the anchoring portion 6 in the front view shown in Fig. 10(A) is greater than the width D of the anchoring portion 6 in the plan view shown in Fig. 6(B). The height K of the anchoring portion 6 is preferably 60 to 90%, and more preferably 70 to 80%, of the height H of the groove-shaped engaging portion 9, and is preferably positioned approximately in the center of the groove-shaped engaging portion 9 in the vertical direction when the precast deck slabs 1Aa, 1Ab or 1Ba, 1Bb are joined, as shown in Fig. 3.

[0046] The width D of the anchoring portion 6 is formed to be approximately equal over the entire length in the vertical direction, and is formed so that it protrudes by approximately the same width from both sides of the male joint anchor portion 11 extending behind it. The width D of the anchoring portion 6 is formed to be larger than the width S of the vertical groove 5 formed in the groove-type engaging portion 9, and as shown in Figure 2, when the anchoring portion 6 is inserted into the groove-type engaging portion 9, there is an overlapping margin U between both sides of the anchoring portion 6 and both sides of the vertical groove 5 in the direction perpendicular to the joint end face (the bridge axis direction). Because this overlapping margin U is formed over the entire length in the height direction of the anchoring portion 6, the engagement area between the female joint 4 and the male joint 7 is increased, and the joint strength between the female joint 4 and the male joint 7 can be increased.

[0047] The male joint anchor portion 11 extending rearward of the anchoring portion 6 is formed in a flat plate shape along a vertical plane. One end of this flat male joint anchor portion 11 protrudes from the joint end surface of the other precast floor slabs 1Ab, 1Bb and is connected along the vertical direction to the center of the width direction of the anchoring portion 6, and the other end is disposed in a state where it is embedded inside the concrete of the other precast floor slabs 1Ab, 1Bb. The rear end of the male joint anchor portion 11 is provided with rear end anchoring portions 11a in a flat plate shape that protrudes on both sides and follows a plane parallel to the joint end surface in a plan view shown in Figure 6(B).

[0048] It is preferable that the male joint anchor part 11 and the fixing part 6 are formed so that the height of the male joint anchor part 11 and the height of the fixing part 6 are approximately equal at their connection part, and that the upper and lower ends of both parts are approximately aligned. This allows the stress acting on the fixing part 6 to be borne approximately evenly by the entire male joint anchor part 11.

[0049] In the embodiment shown in Figure 6(A), the height of the male joint anchor portion 11 is relatively small rearward from the middle portion. The ratio of the height of the rear portion, which is relatively small, to the height of the front portion, which is relatively large, is 40 to 80%, preferably 55 to 75%. When changing the height, if a step or other portion where the height changes suddenly is provided, stress will concentrate there and cause damage, so it is preferable to provide an inclined portion 11b where the height changes gradually, as in the illustrated example. The gradient of this inclined portion 11b in the direction of extension of the male joint anchor portion 11 is 30% or less, preferably 20% or less. The inclined portion 11b may be provided on either the upper or lower end of the male joint anchor portion 11, but it is preferable to provide it on both the upper and lower end edges, as in the illustrated example, to form a tapered shape. The inclined portion 11b is preferably formed on the portion of the male joint anchor portion 11 that is embedded in the concrete of the precast floor slabs 1Ab, 1Bb, and in the portion that protrudes from the joint end surface, it is preferably formed at a constant height that is approximately the same as the height K of the anchoring portion 6. The male joint anchor portion 11 may also be formed at a substantially uniform height over its entire length, which further increases the anchoring strength of the male joint anchor portion 11. In this case, the anchoring portion 6 and rear end anchoring portion 11a connected to the front and rear end edges of the male joint anchor portion 11 are formed at approximately the same height as the male joint anchor portion 11.

[0050] The plate thickness T of the male joint anchor portion 11 may be formed to be approximately constant over its entire length, or may be varied. In either case, it is formed to be smaller than the width S of the vertical groove 5 of the groove-type engaging portion 9.

[0051] The male joint 7 can be manufactured by joining steel plates by welding or other methods, but it is preferable to manufacture it by mold casting, which allows for greater freedom in shape. Manufacturing it by mold casting allows the anchoring portion 6 and male joint anchor portion 11 to be formed as a single unit. By integrating the joint portion body and the anchor portion without welding, crimping, or bolting, the structure is stabilized and concerns about fatigue damage are eliminated, resulting in a high-strength joint structure and facilitating the manufacture of precast deck slabs 1Ab and 1Bb. Furthermore, manufacturing it by mold casting increases the bond strength with concrete, improving the anchorage of the male joint 7.

[0052] (Connection method for bridge axis joint 2) As shown in Figure 7(A), the precast deck 1Ab is installed by vertically dropping the anchoring portion 6 of the male joint 7 of the precast deck 1Ab, which is adjacent in the bridge axis direction, from above onto the groove-type engaging portion 9 of the female joint 4 of the preceding precast deck 1Aa, which has already been installed, and aligning the two (Figure 7(B)). As shown in Figure 7(B), the female joint 4 and the male joint 7 are connected by engaging the male joint anchor portion 11 of the male joint 7 with the vertical groove 5 of the groove-type engaging portion 9, and inserting the anchoring portion 6 into the internal space of the groove-type engaging portion 9 of the female joint 4, thereby joining the two precast decks 1Aa and 1Ab. In this invention, a simple fitting structure is used, using the female joint 4 with the groove-type engaging portion 9 and the male joint 7 with the anchoring portion 6, so that the tolerance for error is large, absorbing manufacturing and construction errors and making alignment easy.

[0053] 7(C), the internal space IS of the groove-type engaging portion 9, the upper space US of the groove-type engaging portion 9, and the gap (horizontal joint MH) between the precast floor slab 1Aa on one side and the precast floor slab 1Ab on the other side are filled with grout material 8. Note that instead of the grout material 8, concrete or mortar may be filled.

[0054] In the above example, it has been explained that a female joint 4 is provided on the joint end surface of the precast deck 1Aa on one side, and a male joint 7 is provided on the joint end surface of the precast deck 1Ab on the other side. However, when joining three or more precast decks in a row, a female joint 4 is provided on one opposing side of a single rectangular precast deck, a female joint 4 is provided on one opposing side, and a male joint 7 is provided on the other opposing side, and the precast decks are installed by joining each precast deck in sequence.

[0055] When joining three or more consecutive precast decks, the female joint 4 is provided on the end face opposite to the male joint 7 of the succeeding precast deck 1Ab installed as described above, and the next succeeding precast deck is installed in the same manner.

[0056] (Structure of joint 3 perpendicular to the bridge axis) The bridge axis perpendicular joint 3 has a recess 20 formed by recessing the middle part in the thickness direction on the joint end surfaces of the precast deck slabs 1Aa and 1Ba on both sides of the joint and on the joint end surfaces of the precast decks 1Ab and 1Bb on both sides of the joint, When the joint end faces of adjacent precast deck slabs 1Aa, 1Ba and 1Ab, 1Bb in the direction perpendicular to the bridge axis are placed opposite each other, the recesses 20 are arranged opposite each other as shown in Figures 8 and 9, and grout material 21 is filled into the gaps (vertical joints MV) including the recesses 20, creating a joint structure.

[0057] As a result, unlike conventional joint structures that have uneven shear keys on the joint end surfaces of adjacent precast deck slabs perpendicular to the bridge axis, the shear keys no longer interfere when lowering the precast deck slab to be erected laterally, and there is no need to move the precast deck slab to be erected laterally after erection.

[0058] Furthermore, by filling the vertical joint MV including the recess 20 with grout material 21, a shear key can be made to function in the vertical joint, making it possible to resist the shear force that occurs between them.

[0059] Furthermore, since the groove width at the upper and lower ends of the vertical joint remains the same as in the conventional case, there is no need to make the filling work of the grout material 21 more complicated.

[0060] This will be explained in more detail below.

[0061] As shown in Figure 10, the recess 20 is a depression formed in the vertical middle of the joint end surfaces of adjacent precast deck slabs 1Aa, 1Ba and 1Ab, 1Bb in the direction perpendicular to the bridge axis, and extends continuously between the joint end surfaces of each precast deck slab with adjacent precast deck slabs in the bridge axis direction over the entire length of the bridge axis direction of each precast deck slab.

[0062] As shown in Figures 9 and 10, the joint end faces above and below the recess 20 each have an upper end face 22 and a lower end face 23 that face each other and are spaced apart by the joint width of the vertical joint when adjacent precast deck slabs are placed opposite each other in the direction perpendicular to the bridge axis, and are provided along the bridge axis direction.

[0063] As shown in Figure 10, the ratio (Z / Y x 100%) of the vertical length Z of the recess 20 to the vertical height Y of the joint end face where the recess 20 is formed is 20 to 95%, preferably 50 to 90%. If it is less than 20%, the function as a shear key is insufficient, and sufficient resistance to the shear force generated at the joint end face cannot be obtained. If it is greater than 95%, the height of the upper end face 22 and the lower end face 23 cannot be sufficiently secured, which may reduce the quality of the vertical joint.

[0064] As shown in Figure 9, when the joint end faces of adjacent precast deck slabs 1Aa, 1Ba or 1Ab, 1Bb in the direction perpendicular to the bridge axis are opposed to each other, the cross-sectional shape of the portion where the recesses 20 face each other preferably forms an ellipse that is long in the vertical direction. This allows air to escape easily when grout material 21 is filled into the vertical joint MV, simplifying the work of filling the joint. However, as long as air can be properly removed, it is also possible to form the grout into shapes such as (A) a diamond, (B) a hexagon, or (C) a square, as shown in Figure 12.

[0065] As shown in Figures 1 and 8, in order to introduce tension between adjacent precast deck slabs 1Aa, 1Ba and between 1Ab, 1Bb in the direction perpendicular to the bridge axis, multiple PC steel members 25 are provided which penetrate the joint section 3 perpendicular to the bridge axis, extend across the entire width in the direction perpendicular to the bridge axis, and are inserted into sheaths 24 arranged at intervals in the direction of the bridge axis.

[0066] As shown in Figure 8, the sheath 24 is composed of a one-side sheath 26 that is buried with its edge facing the joint end surface of the precast deck 1Aa on one side adjacent to the bridge axis in the direction perpendicular to the bridge axis, a other-side sheath 27 that is buried with its edge facing the joint end surface of the precast deck 1Ba on the other side, and a core sheath 28 that is inserted into the one-side sheath 26 before the subsequent erection of the precast deck 1Ba.

[0067] As shown in Figure 13(A), the precast deck slabs 1Aa and 1Ba are arranged adjacent to each other in the direction perpendicular to the bridge axis, and as shown in Figure 13(B), the core sheath 28 is pulled out from the one side sheath 26 and its tip is inserted into the other side sheath 27 on the opposite side (Figure 13(C)), so that the core sheath 28 connects the one side sheath 26 and the other side sheath 27, and the sheath 24 into which the PC steel 25 is inserted is positioned across the entire width in the direction perpendicular to the bridge axis.

[0068] The length of the core sheath 28 is set according to the joint width, and when inserted into the one-side sheath 26, the core sheath 28 is positioned so that its tip protrudes from the one-side sheath 26. On the outer peripheral surfaces of both ends of this core sheath 28, there are provided seal portions 28a that can be sealed between the one-side sheath 26 and the other-side sheath 27 that are attached thereto, in order to prevent the grout material 21 filled in the vertical joint MV from penetrating into the sheath and to prevent the filler material injected into the sheath from leaking out.

[0069] 1, 8, and 10, joint widening portions 29, in which the joint width is widened, are provided from the top surfaces of the precast decks 1Aa, 1Ba, 1Ab, and 1Bb toward the placement portion of the core sheath 28. By providing the joint widening portions 29, it becomes easier to insert a hand or a tool into the joint widening portions 29 to pull out the core sheath 28 from the one-side sheath 26 and insert the tip end into the other-side sheath 27.

[0070] As the PC steel material 25, a wide range of commonly known materials such as PC steel strands, PC steel wires, PC steel rods, and fully threaded PC steel rods used in prestressed concrete can be used.

[0071] In the above example, one side sheath 26 with a core sheath 28 inserted therein is placed on the precast deck 1Aa, which is erected first, but one side sheath 26 with a core sheath 28 inserted therein may also be placed on the precast deck 1Ba, which is erected subsequently.

[0072] (Connection method for joint 3 perpendicular to the bridge axis) The following explains the connection procedure when installing a trailing precast slab 1Ba adjacent to an already installed preceding precast slab 1Aa in the direction perpendicular to the bridge axis. When installing the trailing precast slab 1Ba, as shown in Figure 7, the bridge axis direction joint 2 is connected between this precast slab 1Ba and the already installed precast slab adjacent to it in the bridge axis direction.

[0073] The trailing precast slab 1Ba is installed by dropping it vertically from above, connecting the female joint 4 and male joint 7 between it and the preceding precast slab adjacent in the bridge axis direction. As a result, as shown in Figure 9, the joint end faces of the adjacent precast slabs 1Aa and 1Ba in the direction perpendicular to the bridge axis face each other, and the recesses 20 formed in each precast slab are positioned opposite each other.

[0074] After each precast deck is placed, a hand or tool is inserted through the joint widening portion 29 to pull out the core sheath 28, and the tip is inserted into the sheath on the opposite side.

[0075] After the bottom and end faces of the vertical joints MV are closed with blocking bodies, the gaps are filled with grout 21. This grout 21 can be the same as the grout 8 filled in the horizontal joints MH. Furthermore, simultaneously with the work of filling the vertical joints MV with grout 21, the work of filling the horizontal joints MH that are continuous with the vertical joints MV with grout 8 may be performed.

[0076] After the grout material 21 has hardened, PC steel members 25 are inserted into the sheath 24, tension is introduced, and then grout material is injected into the sheath to fix it in place. [Explanation of symbols]

[0077] 1Aa·1Ab·1Ba·1Bb...Concrete precast deck (precast deck), 2...Bridge axis direction joint, 3...Bridge axis perpendicular direction joint, 4...Female joint, 5...Vertical groove, 6...Anchorage, 7...Male joint, 8...Grout, 9...Groove-type engagement part, 10...Female joint anchor part, 11...Male joint anchor part, 20...Recess, 21...Grout, 22...Upper end face, 23...Lower end face, 24...Sheath, 25...PC steel, 26...One side sheath, 27...Other side sheath, 28...Core sheath, 29...Joint widening part

Claims

1. The bridge is provided with a bridge axis direction joint structure for joining adjacent concrete precast deck slabs in the bridge axis direction, and a bridge axis perpendicular direction joint structure for joining adjacent concrete precast deck slabs in the direction perpendicular to the bridge axis, The bridge axis direction joint structure is a joint end surface of the concrete precast deck slab on one side of the joint part, and female joints with a grooved cross section in a plan view are embedded at a predetermined interval in the horizontal direction with the vertical groove facing outward, On the other side of the joint, at a predetermined interval in the horizontal direction, male joints are embedded at the joint end surface of the concrete precast deck, with their tip ends protruding from the joint end surface of the concrete precast deck, and these male joints have fixing portions at their tips that can engage with the female joints. The female joint of one concrete precast deck slab is engaged with the male joint of the other concrete precast deck slab, joining the concrete precast decks together, and grout is filled in the internal space of the female joint, the space around the female joint, and the gap between the one concrete precast deck slab and the other concrete precast deck slab. The bridge axis perpendicular joint structure has a recess formed on the joint end surfaces of the concrete precast deck slabs on both sides of the joint section, with the middle part in the thickness direction recessed, A joint structure for concrete precast decks, characterized in that the joint end faces of adjacent concrete precast decks facing each other in the direction perpendicular to the bridge axis are positioned opposite each other, and grout material is filled in the gaps between these, including the recesses.

2. In order to introduce tension between adjacent concrete precast deck slabs in the direction perpendicular to the bridge axis, a plurality of PC steel members are provided that penetrate the joint structure perpendicular to the bridge axis, extend across the entire width in the direction perpendicular to the bridge axis, and are inserted into sheaths that are spaced apart in the direction of the bridge axis. The sheaths consist of a one-side sheath that is embedded with its edge facing the joint end surface of one of the adjacent concrete precast decks in the direction perpendicular to the bridge axis, a second-side sheath that is embedded with its edge facing the joint end surface of the other concrete precast deck, and a core sheath that is inserted into either the one-side sheath or the other-side sheath before the subsequent erection of the concrete precast deck.

2. A joint structure for concrete precast deck slabs as described in claim 1, wherein, when the concrete precast deck slabs are placed adjacent to each other in the direction perpendicular to the bridge axis, the core sheath is pulled out and its tip is inserted into the sheath on the opposite side, so that the core sheath is connected between the sheath on one side and the sheath on the other side, and the sheath into which the PC steel is inserted is positioned across the entire width in the direction perpendicular to the bridge axis.

3. A joint structure for a concrete precast deck as described in claim 2, wherein a joint widening portion is provided from the top surface of the concrete precast deck toward the position where the core sheath is located in order to pull out the core sheath.

4. A joint structure for concrete precast decks as described in claim 1, wherein when the joint end faces of adjacent concrete precast decks in the direction perpendicular to the bridge axis are opposed to each other, the cross-sectional shape of the portion where the recesses face each other is an ellipse that is elongated in the vertical direction.

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