Junction structure of wall balustrade and construction method

Abstract

To provide a junction structure of a wall balustrade and a construction method that enable rapid construction even if a work space for installing a mold or the like at a rear side of precast wall balustrade does not exist.SOLUTION: A precast wall balustrade 2 is integrated to a width direction end of a road bridge floor slab 1 by junction mortar placed in a space overlapped with closing reinforcements 3 protruded to an upper surface of the width direction end of the floor slab 1 and looped reinforcements 4 protruded from a lower end of the precast wall balustrade 2 in a bridge axial direction view. A plate-like rear temporary mold 5 is located between an end rear side upper end of the floor slab 1 and a rear side lower end of the precast wall balustrade 2. The front of the rear temporary mold 5 and the closing reinforcements 3 or the looped reinforcements 4 are combined and fixed with a plurality of mold fixing separators 9 to place the junction mortar there. Nut members 12 for mounting the mold fixing separator 9 are mounted to the front of the rear temporary mold 5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This invention relates to a joint structure and construction method for a precast wall parapet at the widthwise ends of the deck of a road bridge, which is integrated with joining mortar poured into the space formed by overlapping, as viewed in the bridge axis direction, closing reinforcement protruding from the top surface of the widthwise end of the deck and loop reinforcement protruding from the lower end of the precast wall parapet, and in particular enables rapid construction even when there is no working space on the back side of the precast wall parapet for installing formwork, etc. [Background technology]

[0002] In recent years, there has been an increase in the use of precast wall parapets manufactured in JIS factories for road bridges, which are installed to prevent vehicles from falling off while moving, in consideration of stable quality, improved strength and durability, labor-saving construction, shorter construction periods, and improved construction environments (reduced noise levels).

[0003] For example, Patent Document 1 describes a wall railing joint structure and construction method in which a precast wall railing is attached to the widthwise end of a road bridge deck, and closing reinforcement and loop reinforcement arranged at the upper end of the deck in the widthwise direction and the lower end of the precast wall railing, respectively, are integrated by pouring joining mortar into the space where they overlap when viewed in the bridge axis direction (hereinafter referred to as the "mortar pouring space").

[0004] In this type of wall parapet construction method, when pouring joining mortar into the mortar pouring space, a mortar pouring formwork is installed on the rear side of the end of the mortar pouring space, i.e., between the upper end of the rear side of the end of the deck and the lower end of the rear side of the precast wall parapet.

[0005] In addition, when there is not enough working space behind the wall parapet and a normal mortar pouring formwork cannot be installed, a stainless steel formwork is installed as the mortar pouring formwork (see Figure 9).

[0006] To briefly explain the steps of the construction method using the stainless steel formwork, a stainless steel formwork 21 for constructing the drainage section is installed at the rear end of the deck slab 20, and then a precast wall balustrade 23 with a stainless steel formwork 22 for the wall balustrade installed is erected at the end of the deck slab 20, and the stainless steel formwork 21 for constructing the drainage section and the stainless steel formwork 22 for the wall balustrade are joined to each other.

[0007] Then, after adjusting the height of the precast wall parapet 23 using the height adjustment bolts 24, 24 protruding from the end of the deck slab 20, a front formwork 25 is installed at the road side end of the joining mortar pouring space A, and joining mortar (non-shrink mortar) is poured into the joining mortar pouring space A. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2017-172144 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, the above-mentioned bridge wall parapet construction method is a construction method that is applied when the deck 20 is constructed by a prestressed concrete (PC) construction method and the drainage portion 21a at the deck end is constructed by on-site construction.

[0010] Furthermore, because this method involves constructing the joints of the precast wall balustrade 23 together with the drainage 21a at the end of the deck, there was the problem that it was difficult to apply when the drainage 21a is constructed as a secondary deck in a factory, such as in the case of a precast prestressed concrete (hereinafter, "PCa / PC") deck.

[0011] The present invention has been made to solve the above-mentioned problems, and has as its object to provide a joint structure and construction method for a wall parapet that enables rapid construction when constructing a precast wall parapet on-site to a PCa / PC deck slab whose cut-off section is constructed in a factory as a secondary deck slab, particularly when there is no working space behind the precast wall parapet and normal formwork cannot be installed. [Means for solving the problem]

[0012] The present invention relates to a joint structure of a wall balustrade in which a precast wall balustrade is attached to the widthwise end of a road bridge deck and integrated with joining mortar poured into the space formed by overlapping, as viewed in the bridge axis direction, closing bars protruding from the upper surface of the widthwise end of the deck slab and loop bars protruding from the lower end of the wall balustrade, a flat back throw-back formwork is placed between the upper end of the back side of the end of the deck slab and the lower end of the back side of the precast wall balustrade, and the joining mortar is poured with the front of the back throw-back formwork connected and fixed to the closing bars or loop bars with a plurality of separators.

[0013] By providing a rear skirt portion that hangs down along the rear throw-away formwork between the rear side upper end of the deck slab and the rear side lower end of the precast wall railing at the rear side lower end of the precast wall railing, the amount of mortar filled into the mortar filling space can be reduced accordingly, and the rear throw-away formwork can be made smaller and the number of separators can be reduced, making it possible to achieve economical construction, labor-saving construction and efficient construction.

[0014] In addition, the rear throw-away formwork can be easily fixed by attaching a nut member for mounting the separator to the front surface of the rear throw-away formwork and installing a fixing plate for fixing the separator at the fixing position of the separator relative to the closing reinforcement or the loop reinforcement.

[0015] In addition, the strength (rigidity) of the rear throw-away formwork can be increased by attaching a reinforcing liner to the front surface of the rear throw-away formwork, and further, by providing a hanging portion on the reinforcing liner for attaching the end of a separator, the rear throw-away formwork can be fixed more easily by hooking and attaching the end of the separator to the hanging portion.

[0016] In addition, when a notch is provided at the lower end of the back side of the precast wall balustrade into which the upper end of the back throw-in formwork fits, the back throw-in formwork can be installed flush with the back surface of the precast wall balustrade. The back throw-in formwork can be made of stainless steel plate, thereby improving the durability of the back throw-in formwork.

[0017] Also, if no notches are provided, the upper edge of the back throw-away formwork can be attached to the lower edge of the back side of the precast wall balustrade with a sealant in between. In this case, since there is a possibility that a gap will occur between the upper edge of the back throw-away formwork and the top of the sealant, which may allow water to accumulate, it is desirable to provide slits for draining water at appropriate intervals in the bridge axis direction at the upper edge of the throw-away formwork.

[0018] In addition, it is preferable to install a front formwork between the upper end of the deck and the lower end of the front side (road side) of the precast wall parapet, which will close the front side (road side) of the mortar pouring space described below, and further make a part of the front formwork a transparent formwork for checking the mortar filling. Effect of the Invention

[0019] According to the present invention, a flat back throw-away formwork is placed between the upper end of the back side of the end of the deck slab and the lower end of the back side of the precast wall balustrade in the space where the closing bars protruding from the upper surface of the widthwise end of the deck slab and the loop bars protruding from the lower end of the wall balustrade overlap when viewed in the bridge axis direction, and joining mortar is poured while the closing bars or the loop bars are connected and fixed with a number of separators.Moreover, since all of these operations can be performed on the deck slab, rapid construction is possible even if there is no work space to install an ordinary formwork on the back side of the precast wall balustrade.

[0020] Furthermore, since the rear throw-away formwork is formed in a very simple flat plate shape, it requires little processing effort and is easy to install, so it can be easily manufactured and installed. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a perspective view showing a joint between a deck end of a road bridge and a precast wall parapet arranged at the deck end, showing one embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing the deck end of the road bridge, the lower end of a precast wall railing, and a back face discard formwork in the embodiment of FIG. 1. [Diagram 3] FIG. 2 is a perspective view showing a joint between a deck end of a road bridge and a precast wall parapet arranged at the deck end in the embodiment of FIG. 1. [Figure 4] 4(a) is a perspective view showing an example of a rear throw-away formwork, and FIG. 4(b) is an enlarged view of part A in FIG. 4(a). [Diagram 5] FIG. 11 is a perspective view showing a joint between a deck end of a road bridge and a precast wall parapet arranged at the deck end, illustrating another embodiment of the present invention. [Figure 6] FIG. 6 is a perspective view showing the deck end of the road bridge, the lower end of the precast wall railing, and the rear throw-out formwork in the embodiment of FIG. 5. [Figure 7] This is an oblique view showing a rear discard formwork having a slit for draining water at the upper edge end. [Figure 8] FIG. 8 is a perspective view showing a joint between the deck end of a road bridge and a precast wall parapet arranged at the deck end, on which the rear discard formwork shown in FIG. 7 has been installed. [Figure 9] FIG. 11 is a perspective view showing a joint between a deck end of a road bridge and a precast wall parapet arranged at the deck end, illustrating another embodiment of the present invention. [Figure 10] FIG. 10 is a perspective view showing the deck end of the road bridge, the lower end of the precast wall railing, and the rear throw-out formwork in the embodiment of FIG. 9. [Figure 11]This illustrates an example of attaching a formwork fixing separator by hooking it onto a rear throw-away formwork, where Fig. 11(a) is an oblique view showing the entire rear throw-away formwork, and Fig. 11(b) is an enlarged view of part A in Fig. 11(a). [Figure 12] 1A to 1C are longitudinal cross-sectional views showing a conventional joining method for a joint between a deck end of a road bridge and a precast wall parapet arranged at the deck end. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Figures 1 to 4 show one embodiment of the present invention, illustrating the joint between the widthwise end of a road bridge deck and a precast wall parapet arranged at its upper end. In the figures, a plurality of closing reinforcements 3 and a plurality of loop reinforcements 4 are arranged in a mortar pouring space A formed by the widthwise end of the deck slab 1 and the lower end of the precast wall parapet 2.

[0023] In addition, a flat rear discard formwork 5 that covers the rear end of the mortar pouring space A is arranged between the upper end of the rear side of the deck slab 1 and the lower end of the rear side of the precast wall railing 2.

[0024] A PCa / PC plate is laid as the deck 1, and a water cutout 1a is formed at the width direction end of the deck 1. In addition, a precast wall balustrade 2 that realizes rapid construction and high durability is arranged.

[0025] The closing bars 3 are arranged in a roughly rectangular shape when viewed perpendicular to the bridge axis, are arranged at intervals in the bridge axis direction, and are fixed to the widthwise end of the deck 1. Like the closing bars 3, the loop bars 4 are arranged in a roughly rectangular shape when viewed perpendicular to the bridge axis, are arranged at regular intervals in the bridge axis direction, and are fixed to the bottom end of the precast wall parapet 2. The closing bars 3 and loop bars 4 are arranged in an alternating lap in the bridge axis direction.

[0026] Furthermore, in the mortar pouring space A, loop reinforcement 6 is arranged as haunch reinforcement on the deck side, and loop reinforcement 7 is arranged as haunch reinforcement on the precast wall parapet side.

[0027] Loop reinforcement 6 is fixed to the front side of the wall parapet of the deck slab 1, and loop reinforcement 7 is fixed to the lower end of the precast wall parapet 2, both of which are formed in an approximately L-shape when viewed in the bridge axis direction, and are arranged at intervals in the bridge axis direction.

[0028] In addition, the drainage section 1a at the end of the deck is formed integrally with the deck 1 in advance at a factory or the like, and the closing reinforcement 3 and loop reinforcement 6 as the haunch reinforcement on the deck side are arranged in advance when the deck slab 1 is manufactured, and the loop reinforcement 4 and loop reinforcement 7 as the haunch reinforcement on the precast wall balustrade side are arranged in advance when the precast wall balustrade 2 is manufactured.

[0029] The rear throw-away formwork 5 is formed into a rectangular flat plate that is long in the bridge axis direction, and is positioned between the upper end portion on the rear side of the end of the deck slab 1 and the lower end portion on the rear side of the precast wall parapet 2, i.e., on the rear side of the end portion of the mortar pouring space A.

[0030] As the rear temporary formwork 5, a highly durable stainless steel temporary formwork is arranged from the viewpoint of ensuring durability against the external environment by making it a permanent formwork that is completely buried.

[0031] In addition, sealing materials 8, 8 made of hard sponge or the like are continuously interposed in the bridge axis direction at the abutting surfaces between the upper end portion on the rear side of the end portion of the deck slab 1 and the lower end portion on the rear side of the precast wall railing 2 and the upper and lower edge ends of the rear throw-away formwork 5.

[0032] Furthermore, a notch 2a that continues in the bridge axis direction is formed on the surface where the lower end of the rear side of the precast wall railing 2 abuts against the upper edge of the rear throw-away formwork, and the upper edge of the rear throw-away formwork 5 is fitted into this notch 2a with sealing material 8 between them, allowing the rear throw-away formwork 5 to be installed flush with the rear of the precast wall railing 2 and preventing rainwater etc. flowing down the rear of the precast wall railing 2 from entering the joint (see Figures 1 and 3).

[0033] In addition, when the notch 2a is not provided, the upper edge end of the rear throw-away formwork 5 is closely adhered to the lower end of the rear side of the precast wall balustrade 2 with a sealing material 8 interposed therebetween (not shown).

[0034] In this case, there is a possibility that a gap may occur between the upper edge of the rear throw-away formwork 5 and the top of the sealing material 8, which may result in water accumulating, so slits 5a for draining water are provided at the upper edge of the rear throw-away formwork 5 at appropriate intervals in the bridge axis direction (see Figures 7 and 8).

[0035] The rear throw-away formwork 5 is fixed by multiple separators (hereinafter referred to as "formwork fixing separators") 9. The formwork fixing separators 9 are arranged in the mortar pouring space A, penetrating between the closing bars 3 and the loop bars 4 in the direction perpendicular to the bridge axis, and are arranged at predetermined intervals in the bridge axis direction.

[0036] The formwork fixing separators 9 are arranged in at least two tiers, one above the other, to reduce deformation of the rear end formwork 5 and to improve adhesion with the PCa / PC deck and the precast wall balustrade. The formwork fixing separators 9 are made of reinforcing bars, etc.

[0037] In addition, one end (the end on the rear throw-away formwork side) 9a of each formwork fixing separator 9 is connected to the rear throw-away formwork 5 by screwing it into a nut member 10 attached to the front surface (the side surface on the mortar pouring space A side) of the rear throw-away formwork 5.

[0038] On the other hand, the other end 9b of each formwork fixing separator 9 is fixed to the side of the closing bar 3 and / or loop bar 4 by a separator fixing plate 11 and a separator fixing nut 12.

[0039] The separator fixing plate 11 is formed in a long flat plate shape in the bridge axis direction, and is installed on the side of the closing bar 3 or loop bar 4, or between the side of the closing bar 3 and loop bar 4. In addition, a through hole 11a is formed in the separator fixing plate 11, penetrating in the direction perpendicular to the bridge axis, and the end 9b of each formwork fixing separator 9 passes through said through hole 11a.

[0040] Then, by tightening the separator fixing nut 12 to the end 9b of the formwork fixing separator 9, the rear throw-away formwork 5 is fixed between the upper end of the rear side of the end of the deck slab 1 and the lower end of the rear side of the precast wall balustrade 2.

[0041] The method of fixing the end 9b of the separator 9 for fixing to the formwork to the side of the closing bar 3 and / or the loop bar 4 is not limited to fixing with the separator fixing plate 11 and the separator fixing nut 12, but can also be fixed using, for example, a clamp structured to simultaneously hold the end 9b of the separator 9 for fixing to the formwork and the side of the closing bar 3 and / or the loop bar 4, or a cable tie or cable tie that simply ties the two together. Also, angle iron or reinforcing bars can be used instead of the separator fixing plate 11.

[0042] Reference numeral 13 denotes a front formwork that closes the front of the mortar pouring space A, and a part of the front formwork 13 is formed to be transparent so that the pouring status of the mortar being poured into the mortar pouring space A can be confirmed. For the same reason, the lower end of the precast wall balustrade 2 is provided with an upward gradient (taper) toward the road side (front side).

[0043] In this configuration, the precast wall balustrade 2 is integrally joined to the widthwise end of the deck slab 1 by pouring mortar such as non-shrink mortar into the mortar pouring space A.

[0044] In addition, since the rear throw-away formwork 5 will be left in place as a reinforcing member for the joint between the upper end portion on the rear side of the end portion of the deck slab 1 and the lower end portion on the rear side of the precast wall parapet 2, the only work required after pouring the mortar is to remove the front formwork 13.

[0045] Figures 5 and 6 show another embodiment of the present invention, in which a rear skirt portion 14 is formed continuously in the bridge axis direction at the lower end of the rear side of the precast wall railing 2, hanging down along the surface of the rear throw formwork 5 between the upper end of the rear side of the end of the deck 1 and the lower end of the rear side of the precast wall railing 2, i.e., at the rear end of the mortar filling space A.

[0046] The rear skirt portion 14 is formed with a substantially rectangular cross section when viewed in the bridge axis direction, and is formed with a sufficient thickness so that it is not easily damaged, particularly by external forces perpendicular to the bridge axis. Furthermore, the lower end of the rear skirt portion 14 is tapered upward toward the road side (front side).

[0047] In addition, since the rear skirt portion 14 narrows the vertical dimension of the mortar filling space A, the number of formwork fixing separators 9 for fixing the rear throw-away formwork 5 can be reduced, and in the embodiment, only one stage is installed.

[0048] Furthermore, as in the embodiment of Figure 1-4, a notch 14a that continues in the bridge axis direction is formed on the back surface of the rear skirt portion 14, and the upper edge end of the rear throw-away formwork 5 is fitted into this notch 14a with sealing material 8 interposed therebetween, thereby allowing the rear throw-away formwork 5 to be installed flush with the back surface of the precast wall railing 2 and preventing rainwater and the like flowing down the back surface of the precast wall railing 2 from entering the joint (see Figures 5 and 6).

[0049] In addition, when the notch 14a is not provided, the upper edge of the rear temporary formwork 5 is closely attached to the rear lower edge of the rear skirt portion 14 with the sealant 8 interposed therebetween (not shown).

[0050] According to the embodiment shown in Figures 5 and 6, by providing a rear skirt portion 14, the amount of mortar filled into the mortar filling space A can be reduced accordingly, and the rear throw-away formwork 5 can be made smaller, and the number of formwork fixing separators 9 can be reduced, thereby enabling labor-saving and efficient construction.

[0051] In addition, by lengthening the water supply route (infiltration path) to the joints for rainwater flowing down the back of the precast wall parapet 2, even if rainwater does infiltrate, the infiltration can be delayed.

[0052] Figures 9-11 show another embodiment of the present invention, in which a reinforcing liner 15 is attached to the front surface (the side surface facing the mortar pouring space A) of the rear throw-away formwork 5 to increase the strength (rigidity) of the rear throw-away formwork 5, and further, small holes 15a are provided in the reinforcing liner 15 as hanging portions for attaching the ends of the formwork fixing separators 16, so that the ends of the formwork fixing separators 16 can be hooked onto the small holes 15a for attachment.

[0053] More specifically, a reinforcing liner 15 is attached continuously in the bridge axis direction to approximately the center of the front surface of the rear throw-away formwork 5.

[0054] The reinforcing liner 15 is formed from a stainless steel angle bar and is attached to the front surface of the rear throw-away formwork 5 at approximately the center by welding or screwing.

[0055] In addition, a plurality of small holes 15a are formed in the reinforcing liner 15 as hooks for attaching one end of the formwork fixing separator 16. The small holes 15a are formed at equal intervals in the bridge axis direction and penetrate the reinforcing liner 15 in the vertical direction.

[0056] The formwork fixing separators 16 penetrate between the closing bars 3 and the loop bars 4 in the mortar pouring space A in a direction perpendicular to the bridge axis, and are arranged at predetermined intervals in the bridge axis direction. The formwork fixing separators 16 are made of reinforcing bars or the like, and are formed with hooks 16a and 16b at both ends, which are bent downward in an L-shape.

[0057] One hook 16a is inserted into the small hole 15a of the reinforcing liner 15 from above, and the other hook 16b is tied to the closing bar 3 or the like with a tie wire.

[0058] During construction, before installing the precast wall railing 2, multiple formwork fixing separators 16 are temporarily attached to the closing bars 3 and placed at specified intervals in the bridge axis direction. Then, after installing the precast wall railing 2, the separators 16 are pulled to the front side of the precast wall railing 2 and fixed to the closing bars 3.

[0059] When the width (height) of the rear discarded formwork 5 is relatively large, the reinforcing liners 15 and formwork fixing separators 16 may be arranged in two stages as in the embodiment shown in Figs.

[0060] Next, the construction method will be described (FIGS. 12(a) to (c)). (1) First, a seal 8 made of sponge or the like is attached continuously in the bridge axis direction to the upper end of the rear side of the end of the deck slab 1.

[0061] (2) Next, the rear throw-away formwork 5 is provisionally placed on the upper end of the rear side of the deck slab 1, and the front of its lower end is brought into close contact with the seal 8. In this case, multiple pieces of the rear throw-away formwork 5 are joined together according to the basic length of each piece, and provisionally placed over the entire length of the precast wall parapet 2 in the bridge axis direction. Additionally, the multiple angle irons 5b attached to the lower end of the rear throw-away formwork 5 are placed against the upper surface of the end of the deck slab 1, and the rear throw-away formwork 5 is temporarily placed in place so that it does not shift downward. The angle irons 5b are attached with intervals in the bridge axis direction. In addition, a formwork fixing separator 9 is placed on the front side of the rear throw-away formwork 5, its end portion 9a on the rear throw-away formwork side is connected to the front side of the rear throw-away formwork 5, and a separator fixing plate 11 and a separator fixing nut 12 are attached to the opposite end portion 9b.

[0062] (3) Next, the precast wall balustrade 2 is erected on the end of the deck 1, and the upper edge of the back discarded formwork 5 is fitted into the notch 2a of the precast wall balustrade 2. In this case, a sealant 8 is applied in advance to the lower end of the back side of the precast wall balustrade 2. Then, after adjusting the height of the precast wall balustrade 2, the rear throw-away formwork 5 is pulled to the front side (road side) via the formwork fixing separator 9 on the lower side of the rear throw-away formwork 5.

[0063] (4) Next, the separator fixing nuts 12 are tightened to temporarily fix the rear throw-away formwork 5, and then the upper-stage formwork fixing separator 9 is placed and the formwork fixing nuts 12, 12 of the upper-stage and lower-stage formwork fixing separators 9, 9 are firmly tightened to fix them in place.

[0064] (5) Next, a front formwork 13 is installed in front of the joint of the precast wall balustrade 2. Then, joint mortar (not shown) is poured between the rear throw-away formwork 5 and the front formwork 13 (mortar pouring space A).

[0065] In addition, by installing a transparent formwork on part of the upper side as the front formwork 13 and giving the lower end of the precast wall parapet 2 an upward slope (taper) toward the road side (front side), it is possible to easily check the status of mortar being poured into the mortar pouring space A. [Industrial Applicability]

[0066] The present invention enables rapid construction, particularly when there is no working space for installing formwork or the like on the rear side of a precast wall balustrade. [Explanation of symbols]

[0067] 1 floor slab 1a Draining section 2 Precast wall parapet 2a notch 3 Obturator muscle 4 Loop Muscles 5 Rear discarded formwork 5a Slit 5b Angle iron 6 Loop reinforcement on deck side as haunch reinforcement 7 Loop reinforcement on the parapet side of precast wall as haunch reinforcement 8. Sealing materials 9 Separator for fixing formwork (separator) 9a One end of the formwork fixing separator 9b The other end of the formwork fixing separator 10 Nut member 11 Separator fixing plate 12 Separator fixing nut 13 Front formwork 14 Back skirt 14a Notch 15 Reinforcement Liner 15a Small hole (latching part) 16 Separator for fixing formwork (separator) 16a One hook of the formwork fixing separator 16b Other hook of formwork fixing separator A Mortar casting space

Claims

1. A wall balustrade joint structure in which a precast wall balustrade is attached to the widthwise end of a road bridge deck slab and integrated with joining mortar poured into the space where closing bars protruding from the upper surface of the widthwise end of the deck slab and loop bars protruding from the lower end of the wall balustrade overlap when viewed in the bridge axis direction, characterized in that a flat back throw-back formwork is placed between the upper end of the back side of the end of the deck slab and the lower end of the back side of the precast wall balustrade, and the joining mortar is poured with the front of the back throw-back formwork connected and fixed to the closing bars or loop bars with a plurality of separators.

2. 2. The wall balustrade joint structure according to claim 1, wherein a rear skirt portion is provided at the rear side lower end of the precast wall balustrade, the rear skirt portion being suspended along the rear throw-away formwork between the rear side upper end of the deck slab and the rear side lower end of the precast wall balustrade.

3. 2. The wall balustrade joint structure according to claim 1, wherein a nut member for mounting the separator is attached to the front surface of the back surface discarding formwork.

4. 2. The wall balustrade joint structure according to claim 1, wherein a reinforcing liner for reinforcing the rear formwork is attached to the front surface of the rear formwork, and a hook portion for attaching the separator to the reinforcing liner is provided.

5. 2. The wall balustrade joint structure according to claim 1, wherein a fixing plate for fixing the separator is installed at a fixing position of the separator relative to the closing reinforcement or the loop reinforcement.

6. 2. The wall balustrade joint structure according to claim 1, wherein a notch is provided at the lower end of the back side of the precast wall balustrade to accommodate the upper end of the back discard formwork.

7. 2. The wall balustrade joint structure according to claim 1, wherein the back face formwork is a stainless steel plate.

8. 2. The wall balustrade joint structure according to claim 1, wherein a sealing material made of a hard sponge or the like is attached to the contact surface between the lower end of the rear side of the precast wall balustrade and the upper edge end of the rear throw-away formwork.

9. The wall balustrade joint structure according to claim 8, characterized in that drainage slits are provided at appropriate intervals in the bridge axial direction at the upper edge end of the back face discard formwork.

10. 1. A method for constructing a precast wall parapet at the widthwise end of a deck slab of a road bridge by pouring joining mortar into the space where closing bars protruding from the upper surface of the widthwise end of the deck slab and loop bars protruding from the lower end of the precast wall parapet overlap when viewed in the bridge axis direction. The method for constructing a wall parapet comprises the steps of: when placing the precast wall parapet above the widthwise end of the deck slab, installing a flat-plate throw-away formwork between the upper end of the deck slab on the rear side and the lower end of the rear side of the precast wall parapet, connecting and fixing the front of the throw-away formwork to the closing bars or the loop bars with a separator, and then installing a front formwork on the front side of the precast wall parapet, and pouring joining mortar between the throw-away formwork and the front formwork.

11. The method for constructing a wall balustrade according to claim 10, wherein a partially transparent formwork is installed as the front formwork.

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