Method for replacing concrete deck slabs for elevated roads

Abstract

To provide a replacement method of a concrete slab for a highway road which is divided into three or more sections in a road width direction, and can perform work while maintaining usage of a plurality of traffic lanes in a heavy traffic section with a heavy traffic volume at all times.SOLUTION: A replacement method of a concrete slab for a highway road includes: installing new precast concrete slabs 22, 22... where a recessed hole or recessed groove-like recess for forming a shear force transmission part is formed in a width direction joint surface part, in a state where other plural work sections are shared as roads for each of the work sections where a concrete slab is divided into three or more sections in a road width direction; forming a joint void part for forming a shear force transmission part between joint surface parts; filling the joint void part for forming the shear force transmission part with an expansive or unshrinkable filler; and forming a shear force transmission part 26 between the new precast concrete slabs 22, 22.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention mainly relates to a method for replacing a concrete floor slab for an elevated road for replacing a concrete floor slab portion in a steel girder bridge composed of a steel girder and a concrete floor slab.

Background Art

[0002] Generally, the concrete floor slab in a steel girder bridge is a structural member that directly supports vehicles. In addition to aging deterioration, it is directly affected by the increase in vehicle traffic volume and the enlargement of vehicles, and there are many damage cases that require replacement. Also, due to the spraying of antifreeze agents in cold regions and the influence of flying salt from the ocean, there are many cases of chloride deterioration due to the corrosion of steel materials in the concrete.

[0003] Conventionally, many repair methods have been developed as countermeasures against damage to the concrete floor slab as described above. As a fundamental countermeasure, there is a method of removing the existing concrete floor slab and constructing a new concrete floor slab for an elevated road there to perform replacement.

[0004] As a method for replacing this type of concrete floor slab, in order to suppress the loss of social benefits due to traffic regulations and traffic congestion, as shown in FIGS. 13 and 14, the road width direction of the concrete floor slab for an elevated road is divided into a primary construction part and a secondary construction part, and the replacement work of the primary construction part is carried out while leaving the existing concrete floor slab of the secondary construction part available as a road. After the completion of the replacement work of the primary construction part, the replacement work of the remaining secondary construction part is carried out in a state where this is used as a road. This method is becoming the mainstream (for example, refer to Patent Document 1).

[0005] In this method, first, as shown in FIG. 13(a), a temporary support girder 3 supported by a steel girder is temporarily installed on the lower surface of the cutting position while the entire width of the existing concrete floor slab 1 is used as a road, and the concrete floor slab installed on a plurality of steel girders is divided at a desired cutting position 2.

[0006] Next, as shown in Figure 13(b), with the secondary construction section 7 in use as a road, the existing concrete slab of the primary construction section 6 is dismantled, and then the existing concrete slab is lifted and removed using a truck crane or the like. Then, as shown in Figure 13(c), precast concrete slabs 8, which are halved versions of the slab 1, are transported into the area where the existing slab of the primary construction section 6 was removed using a truck crane or the like and installed in a continuous line toward the road.

[0007] Then, as shown in Figure 14(d), the new precast concrete slab 8 installed between the steel girders 4, 4 is opened to traffic as a road, the remaining existing slabs of the secondary construction section 7 that have not yet been replaced are removed using a crane device such as a truck crane, and then, as shown in Figure 14(e), half-cut precast concrete slabs 9 are installed in the area where the existing slabs of the secondary construction section 7 were removed, butting them against the precast concrete slab 8.

[0008] Then, the precast concrete slabs 8 and 9 are integrated to form the floor slab 10, which is then put into service across the entire width as shown in Figure 14(f).

[0009] Conventionally, in order to integrate two adjacent precast concrete slabs 8 and 9 in the direction of road width, a common method is to have straight or loop-shaped reinforcing bars protrude from the joint end faces of each precast concrete slab 8 and 9, and to place the straight or loop-shaped reinforcing bars protruding from each precast concrete slab 8 and 9 overlapping in the space formed between the joint end faces of the precast concrete slabs 8 and 9, and then to connect them by pouring cast-in-place concrete into the space in that state (see, for example, Patent Documents 2 and 3).

[0010] However, in recent years, a method has been developed in which a PC tensioning member is inserted between the two precast concrete slabs 8 and 9, and while the PC tensioning member is under tension, its end is fixed to the precast concrete slabs 8 and 9, thereby integrating the precast concrete slabs 8 and 9 and applying prestress to the entire width of the concrete slab using a post-tensioning method.

[0011] Furthermore, as a method for integrating two adjacent precast concrete slabs 8 and 9 in the road width direction, a joint projection is provided on the joint end of one of the precast concrete slabs that abut each other in the road width direction, and a groove-shaped joint recess is formed on the joint end of the other precast concrete slab. When joining the two precast concrete slabs, the joint projection and the joint recess are fitted together, thereby strengthening the rigidity of the joint and making it easier to control the installation height of the precast concrete slabs.

[0012] On the other hand, when replacing concrete bridge decks, in sections with heavy traffic, it is required to keep multiple lanes open at all times from the perspective of ensuring safety during construction.

[0013] However, with the conventional construction method described above, which involves dividing the deck slab into two sections in the direction of the road width, it is difficult to precisely define traffic control lanes. Therefore, in order to cope with heavy traffic sections, it is desirable to divide the deck slab into three or more sections in the direction of the road width and carry out the work in that manner.

[0014] For example, when replacing a road with three lanes on each side, if the bridge deck is divided into two sections in the width direction, replacing the deck for one lane in section 1 allows two lanes in section 2 to be opened to traffic. However, replacing the deck for section 2 only allows one lane in section 1 to be opened to traffic.

[0015] On the other hand, if a three-lane road is divided into three sections in the width direction, it becomes possible to keep any two lanes of section 1 to 3 open while replacing the bridge deck of the other section. [Prior art documents] [Patent Documents]

[0016] [Patent Document 1] Japanese Patent Publication No. 2007-239365 [Patent Document 2] Japanese Patent Publication No. 2009-264040 [Patent Document 3] Japanese Patent Publication No. 2000-328704 [Overview of the project] [Problems that the invention aims to solve]

[0017] However, with the conventional technology described above, when a concrete deck for an elevated road is divided into three or more sections in the width direction and the deck is replaced while at least two lanes remain in service, the following problems arise when replacing the concrete deck of the central section, because the lanes on both outer sections flanking the central section remain in service.

[0018] The conventional construction method described in the aforementioned patent document has a structure in which a joint protrusion and a joint recess are fitted together. Therefore, when dividing a concrete deck slab for an elevated road into three or more sections in the width direction and replacing the deck slab while keeping at least two lanes in service, when lowering a precast concrete slab to be installed in the central section between the precast concrete slabs of the two outer sections, it is not possible to secure space to horizontally move the precast concrete slab in order to fit the joint protrusion into the joint recess, and the joint protrusion on one precast concrete slab interferes with the other precast concrete slab, making it unsuitable for application.

[0019] Furthermore, in the conventional method, in which straight or loop-shaped reinforcing bars are made to protrude from the joint end faces of each precast concrete slab 8, 9, and the straight or loop-shaped reinforcing bars protruding from each precast concrete slab 8, 9 are placed overlapping in the space formed between the joint end faces of the precast concrete slabs 8, 9, and then cast concrete is poured into the space to connect them, a joint width of about 40 cm is generally required to ensure the joint length of the straight or loop-shaped reinforcing bars. However, due to the relationship between the width during construction and the width of traffic restrictions, there was a risk that such a wide joint width could not be secured.

[0020] In addition, in the replacement work of the concrete floor slab, it is desired to quickly lift the traffic control. In the placement of in-situ concrete that requires a series of processes such as formwork assembly, steel bar assembly, concrete placement, curing, and formwork disassembly, there were problems in the process.

[0021] Therefore, in view of such conventional problems, the present invention divides into three or more sections in the road width direction, and aims to provide a method for replacing a concrete floor slab for an elevated road that can perform work while maintaining the use of multiple lanes at all times in a heavy traffic section with a large traffic volume.

Means for Solving the Problems

[0022] The feature of the invention according to claim 1 for solving the above-mentioned conventional problems is in a method for replacing a concrete floor slab for an elevated road that replaces a concrete floor slab supported by a plurality of bridge girders. An operation section is set by dividing the concrete floor slab into at least three or more sections in the road width direction. For each operation section, while using other multiple operation sections as roads, a new precast concrete slab is installed in which recesses for forming a shear force transmission section are continuously formed in the road length direction at the joint surface in the width direction to replace the existing concrete floor slab that has been removed. This process includes the step of lowering the newly installed precast concrete slab from directly above between the already installed precast concrete slabs. A shear force transmission section forming joint gap portion is formed between the joint surfaces of adjacent new precast concrete slabs in the width direction, which consists of a vertical joint portion with a predetermined width and the recesses for forming the shear force transmission section facing each other across the vertical joint portion. An expansive or non-shrinking filler is filled in the shear force transmission section forming joint gap portion to form a shear force transmission section between adjacent new precast concrete slabs in the width direction, and the adjacent new precast concrete slabs are joined.

[0023] The feature of the invention according to claim 2 is that, in addition to the configuration of claim 1, the new precast concrete slab is prestressed by a pre-tensioning method.

[0024] The feature of the invention according to claim 3 is that, in addition to the configuration of claim 1 or 2, each of the newly installed precast concrete slabs has a PC tendon insertion hole with one end communicating with the concave portion for forming the shear force transmission portion and the other end opening to the other widthwise end face or the back surface portion of the concrete slab, and tension is applied to the PC steel bars inserted across adjacent newly installed precast concrete slabs through the PC tendon insertion holes to apply post-tensioning prestress between adjacent newly installed precast concrete slabs.

[0025] The feature of the invention according to claim 4 is that, in addition to the configuration of claim 3, a working concave groove is formed on the widthwise joint end portion of the newly installed precast concrete slab, facing the surface of the concrete slab from the position of the PC tendon insertion hole, and the PC tendon insertion holes of adjacent newly installed precast concrete slabs are connected with a sheath material using the gap between the working concave grooves facing each other.

Advantages of the Invention

[0026] The method for replacing the concrete floor slab for elevated roads according to the present invention, by comprising the configuration according to claim 1, can drop newly installed precast concrete slabs from directly above even when the working sections on both sides are in use as roads, and can form a structure for transmitting shear force between adjacent concrete slabs. Since work can be carried out for each of three or more working sections, it is possible to perform the work of replacing the floor slab while always using a plurality of sections as roads in heavy traffic sections and the like.

[0027] <0***0103>Also, in the present invention, by comprising the configuration according to claim 2, it is possible to ensure the durability when the newly installed precast concrete slab during the replacement work is used as a road, and to shorten the construction period.

[0028] Furthermore, in the present invention, by comprising the configuration according to claim 3, prestress can be introduced between adjacent new precast concrete slabs to enhance the durability of the joint portion.

[0029] Furthermore, by providing the configuration described in claim 4, the connection work of the joint sheath connecting the PC tensioning material insertion holes can be performed smoothly. [Brief explanation of the drawing]

[0030] [Figure 1] This is a partially enlarged plan view of an elevated road that has been replaced using the method for replacing concrete deck slabs for elevated roads according to the present invention. [Figure 2] This is a cross-sectional view taken along line AA, as shown above. [Figure 3] This is an enlarged cross-sectional view showing the joint between the new precast concrete slabs in Figure 2. [Figure 4] This is a cross-sectional view taken along the line BB shown above. [Figure 5] This is an enlarged cross-sectional view showing the joint between the new precast concrete slabs in Figure 4. [Figure 6] (a) is a plan view showing the new precast concrete slabs installed on both sides of the same, (b) is a plan view showing the new precast concrete slabs installed on the inner side of the same, and (c) is a side view showing the joint end face of the same. [Figure 7] (a) to (c) are cross-sectional views showing the state of the replacement work in the first work section in the method for replacing concrete deck slabs for elevated roads according to the present invention. [Figure 8] (d) to (f) are cross-sectional views showing the state of the replacement work in the third work area mentioned above. [Figure 9] (g) to (i) are cross-sectional views showing the state of the replacement work in the second work area as described above. [Figure 10] This is a cross-sectional view showing the state of the connection work for the PC tensioning material insertion holes mentioned above. [Figure 11] This is a cross-sectional view showing another embodiment of an elevated road that has been replaced by the method for replacing concrete deck slabs for elevated roads according to the present invention. [Figure 12] This is a cross-sectional view showing yet another embodiment of the same. [Figure 13](a) to (c) are cross-sectional views showing the state of the replacement work in the first work section in the conventional method of replacing concrete deck slabs for elevated roads using a two-part method. [Figure 14] (d) to (f) are cross-sectional views showing the state of the replacement work in the second work area as described above. [Modes for carrying out the invention]

[0031] Next, an embodiment of the method for replacing concrete slabs for elevated roads according to the present invention will be described based on the examples shown in Figures 1 to 10.

[0032] Figures 1 to 5 show a concrete slab for an elevated road (hereinafter referred to as PC slab 20) constructed by the method of the present invention. This PC slab 20 is constructed by dividing the road width direction of the concrete slab into at least three or more work sections A1 to A3, installing new precast concrete slabs 22, 22... in place of the existing concrete slab 21 in each work section A1 to A3, joining them together in the road width direction, inserting PC tensioning members 23 between adjacent new precast concrete slabs 22, 22 in the width direction, and applying prestress between the new precast concrete slabs by a post-tensioning method by tensioning the PC tensioning members 23, and the entire PC slab 20 is supported by multiple steel girders 24, 24...

[0033] Each work area A1 to A3 is constructed by supporting numerous newly constructed precast concrete slabs 22, 22…, which have been prestressed in the road width direction by a pretensioning method, by arranging them in the length direction of steel girders 24, 24….

[0034] As shown in Figure 6, the newly constructed precast concrete slabs 22, 22… are formed in a rectangular shape in plan view, with the PC slab 20 to be constructed divided according to the number of set work sections A1 to A3. At the ends on the other work section side in the road width direction, i.e., at the joint ends with the newly constructed precast concrete slabs 22, 22… installed in other work sections, recessed grooves 25 for forming shear force transmission sections are formed, which are continuous in the road axis direction.

[0035] The recess 25 for forming the shear force transmission section is formed in the shape of a continuous groove in the direction of the road length, and its upper and lower side edges are tapered, sloping toward the center from the joint side.

[0036] Furthermore, by providing recesses 25 for forming shear force transmission sections at the joint ends of the newly installed precast concrete panels 22, 22..., a joint void for forming shear force transmission sections is formed between the joint surfaces of adjacent newly installed precast concrete panels 22, 22... in the width direction, consisting of a vertical joint section of a predetermined width and the recesses 25 for forming shear force transmission sections facing each other across the vertical joint section.

[0037] Furthermore, the width of the newly installed precast concrete slabs 22, 22… in the road width direction is set so that when installed, a predetermined width, i.e., a joint width of 20 to 30 mm, is formed between adjacent newly installed precast concrete slabs 22, 22, and the joint surfaces are butted together with the said joint width in between.

[0038] The joint voids for forming the shear force transmission section are filled with an expandable or non-shrinkable filler such as mortar, and a shear force transmission section 26 is formed between adjacent newly constructed precast concrete slabs 22, 22 in the width direction, having key-shaped protrusions 26a, 26a that fit into recesses 25 for forming the shear force transmission section, thereby enabling shear force to be transmitted between adjacent newly constructed precast concrete slabs 22, 22...

[0039] Furthermore, each newly constructed precast concrete slab 22, 22… has PC tensioning member insertion holes 28, 28 formed at intervals along the length of the road. One end of these holes communicates with a recess 25 for forming a shear force transmission section, and the other end opens to a tensioning bearing section 27 protruding from the back surface. PC tensioning members 23 are inserted through these PC tensioning member insertion holes 28, 28, spanning between adjacent newly constructed precast concrete slabs 22, 22. After the shear force transmission section 26 is formed, the PC tensioning members 23 are tensioned to introduce prestress using a post-tensioning method, thereby improving the durability of the joints and preventing crack formation.

[0040] Furthermore, at the widthwise joint ends of the newly installed precast concrete slabs 22, 22…, working grooves 29 are formed from the positions of the PC tensioner insertion holes 28, 28 toward the concrete slab surface, and the PC tensioner insertion holes 28, 28 of adjacent newly installed precast concrete slabs 22, 22… can be connected with a joint sheath 30 using the gaps between the opposing working grooves 29, 29. It is preferable that the gaps between the working grooves 29, 29 be approximately 90 mm in order to facilitate smooth operation.

[0041] Furthermore, although not specifically shown in the diagram, pre-tensioning PC tensioning members are embedded in these newly constructed precast concrete slabs 22, 22... under tension to the desired tension, and the return force of these pre-tensioning PC tensioning members introduces prestress in the direction of the road width through a pre-tensioning method.

[0042] Furthermore, the newly constructed precast concrete slabs 22, 22... have reinforcing bar connection sections 31, 31... made of loop reinforcement bars protruding from both ends in the shorter direction, that is, from both ends in the direction of the road length. When adjacent newly constructed precast concrete slabs 22, 22... in the direction of the road length are butted together, the reinforcing bar connection sections 31, 31... of adjacent newly constructed precast concrete slabs in the direction of the road length are overlapped, and cast-in-place concrete 36 is poured between adjacent newly constructed precast concrete slabs 22, 22 in the direction of the road length to join the adjacent newly constructed precast concrete slabs 22, 22... in the direction of the road length.

[0043] Next, an example of replacing a concrete deck slab for an elevated road using the method of the present invention will be described.

[0044] This method involves dividing the existing concrete deck slab 21 shown in Figure 7 into three work sections A1 to A3 in the direction of the road width. With the other work sections A1 to A3 still in use as roads, the deck slab replacement work is carried out in the order of the first, third, and second work sections. After that, the adjacent newly installed precast concrete slabs 22, 22 are joined together to integrate the entire deck slab and complete the replacement work.

[0045] In this embodiment, the floor slab replacement work is carried out in the order of the first, third, and second work areas, but the order of work is not limited to this, and the order of work can be determined arbitrarily.

[0046] Next, we will explain the replacement process for this example step by step.

[0047] a. Installation of temporary support material 32 on the underside of the cut section of the existing concrete slab. As shown in Figure 7(a), the existing concrete deck slab 21 to be replaced is in use and is divided into three work sections A1 to A3 in the width direction. In this embodiment, the work sections A1 to A3 will be defined and explained from left to right in the figure.

[0048] Furthermore, if the boundary between each work section A1 to A3 is cantilevered by the portion that extends from the nearest steel girder 24, 24..., the lower surface of the tip of the cantilevered portion will be supported from below by a temporary support member 32 as needed to bear the downward load from the road surface.

[0049] The temporary support members 32 are, for example, composed of diagonal members installed between the underside of the deck slab and the steel girders 24, 24... In addition to diagonal members, temporary steel girders may also be used as the temporary support members 32.

[0050] b. Cutting of the existing concrete slab and removal of the existing concrete slab in the first work area A1 As shown in Figure 7(b), a guard rail 33 is installed on the upper surface of the edge of the second work area A2 on the side of the first work area A1. Only the second and third work areas A2 and A3 are used as roads with the guard rail 33 as the boundary, blocking passage on the first work area A1. The boundary portion of the existing concrete slab 21 between the first work area A1 and the second work area A2 is cut, and the existing concrete slab 21a in the first work area A1 portion is removed.

[0051] For example, this removal may involve using a crane to lift each section of the existing concrete deck 21 on the road direction side, lowering it to the ground, crushing it to the required size on the ground, and separating the steel and concrete. Alternatively, it may be crushed while still erected on the steel girders 24, 24..., and separating the concrete and steel.

[0052] c. Installation of new precast concrete slabs 22 in the first work area A1. As shown in Figure 7(c), a predetermined number of new precast concrete slabs 22, which have been previously manufactured in the precast concrete structure fabrication yard, are erected on the steel girders 24, 24… of the first work section A1, from which the existing concrete slab 21a has been removed, in the longitudinal direction of the steel girders 24, 24…, and adjacent new precast concrete slabs 22, 22 in the longitudinal direction of the road are joined with cast-in-place concrete 36. In addition, the lower edge of the side of the second work section A2 of the new precast concrete slabs 22 is supported by temporary support members 32, thereby giving the new precast concrete slabs 22 of the first work section A1 sufficient strength to withstand use as a road.

[0053] The installation of the new precast concrete slab 22 involves lowering it from directly above the first work area A1 using a crane or similar equipment so that it is positioned in a butt-joint configuration with the end face of the second work area A2. Since there are no protruding parts at the widthwise end of the new precast concrete slab 22, it can be lowered directly downwards.

[0054] d. Removal of the existing concrete slab in the third work area A3. As shown in Figure 8(d), the newly installed precast concrete slab 22 in the first work area A1 is made strong enough to be used, and temporary pavement 34a is applied to the surface as needed. Then, the temporary guardrail 33 that was previously installed on the edge of the second work area A2 is moved to the side edge of the second work area A2 toward the third work area A3, the first work area A1 and the second work area A2 are opened to use as roads, and the third work area A3 is closed to use.

[0055] In this state, as shown in Figure 8(e), with passage over the third work area A3 blocked, the boundary portion of the existing concrete slab 21 between the second work area A2 and the third work area A3 is cut, and the existing concrete slab 21c in the third work area A3 portion is removed.

[0056] e. Installation of new precast concrete slab 22 in the third work area A3. As shown in Figure 8(f), a predetermined number of new precast concrete slabs 22, which were previously manufactured in the precast concrete structure fabrication yard, are erected on the steel girders 24, 24… of the third work section A3, where the existing concrete slab 21c has been removed, in the longitudinal direction of the steel girders 24, 24…, and adjacent new precast concrete slabs 22, 22 in the longitudinal direction of the road are joined with cast-in-place concrete 36. In addition, the lower edge of the second work section A2 side of the new precast concrete slabs 22 is supported by temporary support members 32, so that the new precast concrete slabs 22 of the third work section A3 have sufficient strength to withstand use as a road.

[0057] The installation of the new precast concrete slab 22 involves lowering it from directly above the third work area A3 using a crane or similar equipment so that it is positioned in a butt-joint configuration with the end face of the second work area A2. Since there are no protruding parts at the widthwise end of the new precast concrete slab 22, it can be lowered directly downwards.

[0058] f. Removal of the existing concrete slab in the second work area A2. As shown in Figure 9(g), the newly installed precast concrete slab 22 in the third work area A3 is made to a usable strength, and temporary pavement 34a is applied to the surface as needed. Then, the temporary guardrail 33 that was previously installed on the edge of the second work area A2 is moved to the side edge of the second work area A2 in the third work area A3, and a new guardrail 33 is installed on the side edge of the second work area A2 in the first work area A1. The first work area A1 and the third work area A3 are opened to the public as roads, and the second work area A2 is closed to the public.

[0059] In this state, as shown in Figure 9(h), the existing concrete slab 21b of the second work area A2, which has already been separated from the first work area A1 and the third work area A3, is removed.

[0060] g. Installation of new precast concrete slabs 22 in the second work area A2. As shown in Figure 9(i), a predetermined number of new precast concrete slabs 22, 22, ... which were previously manufactured in the precast concrete structure fabrication yard, are erected on the steel girders 24, 24, ... of the second work area A2 from which the existing concrete slab 21b has been removed, arranged in the length direction of the steel girders 24, 24, ... and the adjacent new precast concrete slabs 22, 22 in the length direction of the road are joined with cast-in-place concrete 36.

[0061] Since new precast concrete slabs 22, 22… (or existing concrete floor slabs 21a or 21c, depending on the work order) are already installed on both sides of the second work area A2, i.e., in the first work area A1 and the third work area A3, the new precast concrete slab 22 in the second work area A2 is lowered from directly above the second work area A2 using a crane or the like, so that both ends in the width direction are aligned with the end faces of the new precast concrete slabs 22, 22… installed in the first and third work areas A1 and A3, respectively. At this time, since there are no protrusions at the width direction ends of the new precast concrete installed in each work area A1 to A3, adjacent new precast concrete slabs 22, 22 can be lowered directly below without interfering with each other.

[0062] Then, when the new precast concrete slabs 22, 22… are installed in the first to third work areas A1 to A3, a joint void for forming a shear force transmission section is formed between the joint surfaces of adjacent new precast concrete slabs 22, 22 in the width direction, consisting of a vertical joint section of a predetermined width and a recess 25 for forming a shear force transmission section that faces the vertical joint section.

[0063] h. Connection of PC tensioning material insertion holes 28, 28 In either of the newly constructed precast concrete slabs 22, 22… that are adjacent to each other in the width direction, a joint sheath 30 is provided in a state where it is pulled into the PC tensioning member insertion hole 28, as shown in Figure 10(a).

[0064] The joint sheath 30 is formed in a tubular shape with a male threaded portion screwed onto its outer circumference. It is screwed into the female threaded portion formed on the recessed end of the PC tensioning material insertion hole 28 and can be inserted into and removed from the PC tensioning material insertion hole 28 by rotating it. It can also be screwed into the end of the other PC tensioning material insertion hole 28 to connect the two PC tensioning material insertion holes 28.

[0065] Therefore, in the first to third work areas A1 to A3, once the new precast concrete slabs 22, 22… are installed, a worker inserts their hand into the gap between the opposing work grooves 29, 29 and rotates the joint sheath 30, which was pulled into the PC tensioner insertion holes 28, 28, connecting the PC tensioner insertion holes 28, 28 of adjacent new precast concrete slabs 22, 22… with the joint sheath 30, as shown in Figure 10(b).

[0066] i. Formation of the shear force transmission section 26 In parallel with the connection work of the PC tensioner insertion holes 28, 28, formwork is installed on the lower surface of the joint and the end face in the road length direction, and as shown in Figures 3 and 5, an expandable or non-shrinkable filler is filled into the joint void for forming the shear force transmission section, and by curing and hardening the filler, a shear force transmission section 26 is formed between the newly constructed precast concrete slabs 22, 22 adjacent to each other in the width direction.

[0067] The shear force transmission section 26 is formed when a filler such as mortar is filled into the recesses 25, 25 for forming the shear force transmission section, thereby creating key-shaped protrusions 26a, 26a, and a structure is formed in which shear force is transmitted between adjacent newly constructed precast concrete slabs 22, 22 in the width direction.

[0068] j. Introduction of prestress Once the filler has hardened and a shear force transmission section 26 has been formed between adjacent newly constructed precast concrete slabs 22, 22 in the width direction, a PC tensioning member 23 for post-tensioning is inserted through the PC tensioning member insertion holes 28, 28 so as to span between adjacent newly constructed precast concrete slabs 22, 22 in the width direction. As shown in Figure 10(c), both ends of the tensioning member are then fixed to the tension bearing sections 27 formed on the back surface of the newly constructed precast concrete slabs 22, 22… using fixing devices 35, thereby introducing prestress.

[0069] This prestress will be introduced between the anchoring devices 35, 35, and prestress will be introduced in the road width direction of adjacent newly constructed precast concrete slabs 22, 22… in the width direction, and both newly constructed precast concrete slabs 22, 22… will be integrated.

[0070] k. Removal of temporary guardrails and temporary support materials 32, and commencement of full-width operation. After constructing the new PC slab 20 in this manner, the temporary guardrails 33, 33 and temporary support members 32 are removed as shown in Figures 2 to 5, new pavement 34 is laid over the entire road, and the entire width of the replaced PC slab 20 is opened to traffic as a road, thus completing the replacement.

[0071] In the above-described embodiment, the work was carried out by dividing a road with three lanes in each direction into three sections, but the work may also be carried out by dividing it into four or more sections.

[0072] Furthermore, in the above-described embodiment, we explained a case in which both ends of the PC tensioning material 23 for post-tensioning are fixed with anchoring devices 35 to the tension bearing portions 27 formed on the back surface of the newly installed precast concrete slabs 22, 22… in a tensed state to introduce prestress. However, the method of introducing prestress between adjacent newly installed precast concrete slabs 22, 22 is not limited to this, and the fixing position of the PC tensioning material 23 is not particularly limited.

[0073] For example, as shown in Figure 11, one end of the PC tensioning member 23 may be fixed to a tensioning bearing portion 27 formed on the back surface of the newly constructed precast concrete slab 22 using a fixing device 35, and the other end may be fixed to the side surface (road width side end surface) of the newly constructed precast concrete slab 22 using a fixing device 35. Alternatively, as shown in Figure 12, a single PC tensioning member 23 may be passed through multiple newly constructed precast concrete slabs 22, 22... that are connected in the road width direction, and both ends of the tensioning member 23 may be fixed to both end surfaces in the road width direction using fixing devices 35. [Explanation of Symbols]

[0074] 20 PC floor slab 21 Existing concrete slab 22 Newly constructed precast concrete panels 23 PC tendons 24 Steel girder 25 Recess for forming shear force transmission section 26 Shear force transmission section 27 Tension and pressure area 28 PC tensioner insertion holes 29 Working grooves 30 Joint Sheaths 31 Reinforcement bar connection 32 Temporary support materials 33 Guardrail 34 Pavement 35 Fixing device

Claims

1. In a method for replacing concrete deck slabs for elevated roads, which involves replacing concrete deck slabs supported by multiple bridge girders, A work area is set up in which the concrete slab is divided into at least three or more sections in the direction of the road width. When installing a new precast concrete slab in each work area, in place of the existing concrete slab that has been removed while other work areas are still in use as roads, the new slab has a recess for forming a shear force transmission section formed continuously in the road length direction on the width direction joint surface, and the process includes the step of lowering the new precast concrete slab from directly above between the already installed new precast concrete slabs, A joint void for forming a shear force transmission section is formed between the joint surfaces of adjacent newly constructed precast concrete panels in the width direction, consisting of a vertical joint section of a predetermined width and a recess for forming the shear force transmission section that faces the vertical joint section. A method for replacing a concrete deck slab for an elevated road, characterized by filling the joint void for forming the shear force transmission section with an expandable or non-shrinkable filler, forming a shear force transmission section between adjacent newly installed precast concrete slabs in the width direction, and joining the adjacent newly installed precast concrete slabs.

2. The method for replacing a concrete deck slab for an elevated road according to claim 1, wherein the newly installed precast concrete slab is prestressed by a pretensioning method.

3. Each of the newly constructed precast concrete slabs is provided with a PC tensioning member insertion hole that is open at one end to the recess for forming the shear force transmission section and at the other end to the other end face in the width direction or on the back surface of the concrete slab. A method for replacing concrete deck slabs for elevated roads according to claim 1 or 2, wherein PC steel members inserted across adjacent newly constructed precast concrete slabs through the PC tensioning member insertion holes are tensioned to apply post-tensioning type prestress between adjacent newly constructed precast concrete slabs.

4. At the widthwise joint end of the newly constructed precast concrete slab, a working groove is formed extending from the position of the PC tensioning member insertion hole toward the concrete slab surface. A method for replacing a concrete slab for an elevated road, according to claim 3, wherein the gaps between opposing working grooves are used to connect the PC tensioner insertion holes of adjacent newly installed precast concrete slabs with a sheath material.

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