JP2020090856A - Joining method and adjustment member of precast member - Google Patents

Abstract

To provide a method for joining precast members which does not utilize a wet joint in a case of joining precast members to which prestress is introduced, and also provide an adjustment member for use therein.SOLUTION: A method for joining precast members, comprising a temporary placing process for temporarily placing a plurality of precast floor slabs 1 in places other than the construction site, and a main assembling process for performing main assembling of the plurality of precast floor slabs 1 at the construction site. The temporary placing process performs a temporary member placing work to place a pair of precast floor slabs 1 with a gap between the end faces, a formwork assembling work to install a formwork on the bottom and side of the gap, a member forming work to fill the gap with a cement-based material to form an adjustment member 3, and a form removal work to remove the formwork. Further, the main assembling process performs a member carrying-in work to carry in the precast floor slab 1 and the adjustment member 3 to the construction site, and a member connecting work to connect the pair of precast floor slabs 1 via the adjustment member 3.SELECTED DRAWING: Figure 1

Description

The present invention relates to precast member technology.

A precast member may be used for the purpose of shortening the construction period. For example, in the construction to renew a deteriorated floor slab on an in-service road bridge, it is necessary to finish the construction in a short time, such as performing the renewal work at midnight when the traffic volume is low and opening the next morning. The precast member may be used to shorten the construction period. On the other hand, the precast member is deformed due to shrinkage during production or introduction of prestress. In particular, precast members made of ultra-high-strength fiber-reinforced concrete can increase the strength and weight of the members, but since they shrink more than ordinary concrete, large deformation will occur when manufacturing large members. . If such a precast member is used and a dry joint is used that connects the end faces to each other as they are, the error of each precast member will be added, and a large error will occur in the final product. I'm worried. Therefore, in the case of connecting a plurality of precast members like a deck of a bridge, there is a possibility that the finished shape accuracy cannot be ensured as a final structure. Such a problem is not limited to the floor slab of the bridge, and may similarly occur in other structures that connect a plurality of precast members such as a box girder.

Therefore, by adopting a so-called wet joint in which cast concrete or the like is cast between the precast members, an error of the precast members may be absorbed (for example, refer to Patent Document 1).
Since the wet joint needs to be cured by placing concrete or the like at the joint at the construction site, it takes time and hinders shortening of the construction period. Therefore, it cannot be adopted when there is a time constraint.

JP, 2018-059357, A

An object of the present invention is to develop a joining technique for joining precast members without using a wet joint.

INDUSTRIAL APPLICABILITY The present invention can realize a joining technique that does not use a wet joint in the slab renewal work using a precast slab.
A method for joining a precast member, which is the first invention for solving the above-mentioned problems, in a place other than a construction site, a plurality of precast members constituting a predetermined length range are temporarily placed, and in a lacking portion within the predetermined length range. The method includes a step of casting a cement-based material to form an adjusting member, and a step of performing a connecting operation using the precast member used for temporary placement at the construction site and the adjusting member.
Further, the joining method of the precast member of the second invention, a temporary placement step of temporarily placing a plurality of precast members at a place other than the construction site, and a main assembly process of permanently assembling the plurality of precast members at the construction site. Be prepared. In the temporary placement step, a member temporary placement operation of placing a pair of the precast members in a state where a gap is left between the end faces, a formwork assembly work of installing a formwork on the lower surface and the side surface of the gap, and A member forming operation of filling the clearance with cement-based material to form an adjusting member and a demolding operation of demolding the mold are performed. Further, in the main assembly step, a member loading operation of loading the precast member and the adjusting member into the construction site and a member connecting operation of connecting a pair of the precast members via the adjusting member are performed.
According to the method of joining the precast members, since the precast members are connected using the adjustment member made of the precast formed by the matchcast method using the end surface of the precast member as a mold, shrinkage during the production of the precast member The structure can be constructed in a state in which an error caused by warping when introducing prestress or the like is absorbed. Further, since the adjusting member is a precast member, it is not necessary to use a wet joint on site, and the work can be simplified. In addition, high quality construction can be performed in a short time.

In the member temporary disposing work, if another precast member is connected to the end surface of the precast member on the side opposite to the gap side, an adjusting member is formed for each predetermined number of precast members in the main assembly process. Even in such a case, it is possible to form the adjusting member capable of absorbing the error generated by connecting the plurality of precast members.
Further, in the member temporary disposing work, it is desirable to adjust the angle of the end face of the precast member so that the inclination angle is expected to occur on the end face of the precast member in the main assembly process. With this configuration, for example, an adjusting member that absorbs an error caused by connecting a plurality of precast members can be formed by disposing one precast member in the temporary placement step.
Further, in the demolding work, one of the pair of precast members is removed from the adjusting member, and in the member carrying-in work, the adjusting member is carried in while being attached to the end face of the other precast member. You may. By doing so, it is possible to further shorten the construction period by reducing the number of man-hours in the main assembly process.

Further, the adjusting member of the present invention is a member made of precast concrete, which is provided between the precast members at the joint between the precast members. The adjustment member has a shape in which the abutment surface with the precast member is formed by a matchcast method, and has a shape capable of absorbing a manufacturing error or a construction error of the precast member. By using this adjusting member, it is possible to absorb errors caused by shrinkage during manufacturing of the precast member and warpage during the introduction of prestress, and as a result, a structure in which a plurality of precast members are connected is of high quality. Can be built on. Further, while the same effect as the wet joint can be secured by the member made of precast, it is possible to omit the on-site concrete pouring and curing required when the wet joint is adopted.

According to the joining method of the precast member and the adjusting member of the present invention, it becomes possible to construct a high-quality structure by absorbing an error that occurs during manufacturing of the precast member, an error that occurs when introducing prestress, and the like, and The work can be simplified and the construction period can be shortened compared with the case where the wet joint is adopted.

It is a figure which shows the precast floor slab of embodiment of this invention, (a) is a top view seen from lower side, (b) is sectional drawing. It is a figure which shows the state which put the precast floor slab temporarily, (a) is a side view, (b) is a top view. It is a figure which shows a form, (a) is a side view, (b) is a top view. It is sectional drawing which shows a demolding jig. It is sectional drawing which shows a temporary fixing jig. It is a side view which shows a tilt adjusting member.

<First embodiment>
In the first embodiment, a case where a precast floor slab (precast member) 1 is used to shorten the construction period in a business of renewing an aged slab of a bridge in service will be described. The precast floor slab 1 is made of a prestressed concrete member. In the slab renewal business, a plurality of precast slabs 1 are connected in the bridge axis direction. As shown in FIG. 1, the precast floor slab 1 has grid-like ribs 11 formed on the lower surface. In addition, a joint portion 12 is formed at an end portion of the lower surface of the precast floor slab 1. A bolt insertion hole 13 is formed in the joint portion 12. It should be noted that the formation location of the joint portion 12 is not limited to the lower surface of the precast floor slab 1. The precast floor slabs 1 are connected to each other by bolts B inserted into the bolt insertion holes 13 of both precast floor slabs 1 in a state of being abutted with the ends of the other adjacent precast floor slabs 1.
The precast floor slab 1 is deformed such as warp due to shrinkage (manufacturing error) during manufacturing and introduction of prestress. Therefore, when a plurality of precast floor slabs 1 are connected by a dry joint, an error (warp) of the precast floor slabs 1 is accumulated, and a large error occurs at the ends of the bridge. In the present embodiment, the joining method of the precast member and the adjusting member 3 that can absorb the deformation generated in the precast floor slab 1 are adopted.

The precast member joining method according to the present embodiment includes a temporary placement step of temporarily placing a number of precast floor slabs 1 corresponding to a predetermined length range, and a main assembly step of main assembly of the precast floor slabs 1 temporarily placed in the temporary placement step. It has and.
In the temporary placement process, temporary member placement work, formwork assembly work, member forming work, and demolding work are performed in a place other than the construction site.
In the member temporary placement work, as shown in FIGS. 2A and 2B, the pair of precast floor slabs 1 (the first joining portion floor slab 14 and the second joining portion floor slab 15) are joined to each other at their end faces. It is arranged with a gap S between them. At this time, the other end surface of the first joint floor slab 14 (the end surface opposite to the second joint floor slab 15) and the other end surface of the second joint floor slab 15 (first joint floor) Another precast floor slab 1 (general floor slab 16) is connected to each of the end faces opposite to the slab 14). It should be noted that the number of general part floor slabs 16 bonded to the first joint part floor slab 14 and the second joint part floor slab 15 is not limited. The floor slab 16 for general parts may be installed as necessary.

In the formwork assembling work, as shown in FIGS. 3(a) and 3(b), between the pair of precast floor slabs 1 (between the first joint floor slab 14 and the second joint floor slab 15). The mold 2 is installed on the lower surface and the side surface of the gap S (the lacking portion within the predetermined length range) formed in (1).
The bottom frame 21 installed on the lower surface of the gap S is made of a steel plate. The material forming the bottom mold 21 is not limited. On the upper surface of the bottom mold 21 in the bridge axial direction, the ends of the first joint floor slab 14 and the second joint floor slab 15 are placed. A waterproof rubber or grease is interposed between the upper surface of the bottom form 21 and the lower surface of each precast floor slab 1 to ensure water tightness. The bottom frame 21 and the precast floor slab 1 are fixed with a jig such as a bolt, if necessary.

The side surface formwork 22 installed on the side surface of the gap S is composed of a structural member having an L-shaped cross section. The side surface form 22 is arranged so that one piece (bottom plate 23) faces the lower side and the other piece (side plate 24) faces the side surface of the gap S. The end portion of the side plate 24 in the bridge axis direction is in contact with the end portion of the precast floor slab 1 on the side of the gap S. The side plate 24 is formed with insertion holes 25, which are elongated holes, one by one, corresponding to the contact points with the precast floor slab 1. That is, the side plate 24 is formed with insertion holes 25 (two insertion holes 25 in total) at the front end and the rear end in the bridge axis direction. The side surface form 22 is fixed to the precast floor slab 1 by screwing the bolt B inserted into the insertion hole 25 into the precast floor slab 1. At this time, watertight rubber or grease is provided between the side surface form 22 and the precast floor slab 1 to ensure watertightness. The insertion hole 25 does not necessarily have to be a long hole, and may have a circular shape larger than the outer diameter of the shaft portion of the bolt B, for example.

It should be noted that in the gap S, a cylindrical body 31 is arranged corresponding to the position of the bolt insertion hole 13 of the adjacent precast floor slab 1. The cylindrical body 31 has an inner diameter equivalent to that of the bolt insertion hole 13 and has strength that does not deform due to the pressure of the concrete poured in the member forming work. The material forming the cylindrical body 31 is not limited, and for example, a steel pipe or a vinyl chloride pipe may be used.
Further, in the present embodiment, a release agent (not shown) is applied to the end surface of the first joint floor slab 14 and the inner surface of the mold 2 in advance. The release agent may also be applied to the end surface of the second joint floor slab 15.

In the member forming work, concrete is filled in a region surrounded by the formwork 2 (gap S between the first joint part floor slab 14 and the second joint part floor slab 15) and cured until a predetermined strength is exhibited. To do. When the concrete is hardened, the adjusting member 3 is formed in which the abutment surface with the precast floor slab 1 (the first joint floor slab 14 or the second joint floor slab 15) is formed by the matchcast method. The material forming the adjusting member 3 is not limited to concrete as long as it is a cement material, and may be mortar or non-shrink mortar, for example. In addition, the adjusting member 3 may be provided with a reinforcing bar if necessary.

In the demolding work, the mold 2 is demolded after the concrete filled in the gap S exhibits a predetermined strength. In the present embodiment, the first joint floor slab 14 (one precast floor slab 1 of the pair of precast floor slabs 1) is removed from the adjusting member 3 and is not joined to the second joint when the mold 2 is not released from the mold. The adjusting member 3 is left on the end face of the floor slab 15 (the other precast floor slab 1). The adjusting member 3 does not necessarily have to be left on the end face of the second joint floor slab 15, and may be removed from both precast floor slabs 1.
In the demolding work, the demolding jig 4 is used. As shown in FIG. 4, the demolding jig 4 is fixed to the adjusting member 3 and the first joint floor slab 14. Inserts 32 and 17 are embedded in advance in the adjusting member 3 and the first joint floor slab 14, respectively, and the jig body 41 is fixed via bolts 42 screwed into the inserts 32 and 17. The jig body 41 is composed of a component member having an L-shaped cross section. The jig body 41 fixed to the adjusting member 3 and the jig body 41 fixed to the first joint floor slab 14 face each other. The jig main body 41 fixed to the adjusting member 3 is provided with a long bolt 43 projecting toward the first joint floor slab 14 side so as to be able to move forward and backward. When the long bolt 43 is extended toward the first joint floor slab 14, a pressing force is applied to the jig body 41 fixed to the first joint floor slab 14, so that the first joint floor The plate 14 is separated from the adjusting member 3. When removing the adjusting member 3 from both precast floor slabs 1, the demolding jig 4 may be fixed to the first joint floor slab 14 and the second joint floor slab 15.

In the main assembly process, a member loading operation and a member connecting operation are performed.
In the member loading operation, the plurality of precast floor slabs 1 used in the temporary placing step and the adjusting member 3 formed in the temporary placing step are loaded into the construction site. At this time, the adjusting member 3 is carried in while being attached to the end face of the second joint floor slab 15.
When the members are carried in, as shown in FIG. 5, the adjusting member 3 is fixed to the end face of the second joint floor slab 15 via the temporary fixing jig 5. The temporary fixing jig 5 is fixed to the inserts 32 and 17 embedded in advance in the adjusting member 3 and the second joint floor slab 15. That is, the temporary fixing jig 5 is disposed across the adjusting member 3 and the second joint floor slab 15 to connect the adjusting member 3 and the second joint floor slab 15. ..

In the member connecting work, as shown in FIGS. 1A and 1B, the first joint part floor slab 14 and the second joint part floor slab 15 are connected via the adjusting member 3. With the adjusting member 3 interposed between the first joint floor slab 14 and the second joint floor slab 15, the bolt insertion hole 13 of the first joint floor slab 14 and the bolt of the adjusting member 3 By inserting the bolt B into the insertion hole (cylindrical body 31) and the bolt insertion hole 13 of the second joint floor slab 15 and screwing the bolt B into the nut N, the first joint floor slab 14 and The two-joint floor slab 15 is connected.
In addition, the slab 14 for general parts used in the temporary placing step is connected to the slab 14 for the first joint part and the slab 15 for the second joint part.

According to the precast member joining method and the adjusting member 3 of the present embodiment, the precast floor slab 1 is formed by using the precast adjusting member 3 formed by the matchcast method using the end surface of the precast floor slab 1 as a frame. Because of the connection, the precast floor slab 1 can be connected in a state in which an error or the like caused by shrinkage at the time of manufacturing the precast floor slab 1 or warpage at the time of introducing prestress is absorbed.
Further, since the adjusting member 3 is a precast member formed at a place other than the construction site, it is not necessary to use a wet joint on the site, work can be simplified, and high-quality construction can be performed in a short time. It will be possible.
Since the adjusting member 3 is conveyed while being attached to the end face of the second joint floor slab 15, it is possible to reduce the risk of the thin adjusting member 3 being damaged during transportation. Further, it is not necessary to secure a space for individually transporting the adjusting member 3.

<Second embodiment>
In the second embodiment, similarly to the first embodiment, in a project of renewing an aged floor slab of a bridge in service, joining of precast members capable of absorbing deformation generated in the precast floor slab 1 The method and the case of using the adjusting member 3 will be described.
The joining method of the precast members includes a temporary placement step of temporarily placing a number of precast floor slabs 1 corresponding to a predetermined length range, and a main assembly step of permanently assembling the precast floor slabs 1 temporarily placed in the temporary placement step. There is.
In the temporary placement process, temporary member placement work, formwork assembly work, member forming work, and demolding work are performed in a place other than the construction site.

In the member temporary placement work, the pair of precast floor slabs 1 (the first joining portion floor slab 14 and the second joining portion floor slab 15) are placed with a gap S between the end faces.
At this time, as shown in FIG. 6, an inclination adjusting member 6 is arranged at the end portions of the pair of precast floor slabs 1 on the abutting surface side. The inclination adjusting member 6 has a warp height of the precast floor slab 1 which is expected to occur at the joint when a number of the precast floor slabs 1 corresponding to a predetermined length range are connected. Is a member that lifts the end of the. That is, the ends of the first joint part floor slab 14 and the second joint part floor slab 15 on the side of the gap S (butting surface side) are lifted by the tilt adjusting member 6, and the angle of the end faces is adjusted. ing. The tilt adjusting member 6 may be configured to be expandable and contractable so that the height can be adjusted. At this time, the water blocking plate 61 is arranged on the lower surface of the gap S.
In addition, the details of the temporary placement process (contents of the mold assembling work, member forming work, and demolding work) are the same as those in the first embodiment, and thus detailed description thereof will be omitted.
Further, since the contents of this assembling step are the same as those in the first embodiment, detailed description will be omitted.

According to the joining method of the precast member and the adjusting member 3 of the present embodiment, the adjusting member 3 is formed by the matchcast method in the state where the angle of the end surface of the precast floor slab 1 is adjusted. It is not necessary to connect the slab for general parts 16 to the slab for joints 14 and the slab for second joints 15. Therefore, in the temporary placement step, it is possible to omit the labor required for joining the required number of general-use floor slabs 16 together. Further, even when the work space corresponding to the predetermined length range cannot be secured in the work place of the temporary placement step, the adjusting member 3 can be molded.
Other functions and effects of the second embodiment are similar to those of the first embodiment, and detailed description thereof will be omitted.

Although the embodiment according to the present invention has been described above, the present invention is not limited to the above-described embodiment, and each component can be appropriately modified without departing from the spirit of the present invention.
In the above embodiment, the case where a plurality of precast floor slabs 1 into which prestress has been introduced is connected in the bridge axis direction at the site has been described, but prestress may be introduced at the site. For example, after the plurality of precast floor slabs 1 are installed at predetermined positions, the tension material (PC steel wire, PC steel rod, PC) is provided in the through holes for tension material placement provided in the precast floor slab 1 and the adjusting member 3 in advance. The prestress may be introduced at the site by inserting a stranded steel wire or the like, or the prestress may be introduced at the site by an out cable (outer cable). Since the adjustment member 3 is interposed at the joint between the precast floor slabs 1, the displacement (error) during the production of the precast floor slab 1 is absorbed by the adjustment member 3 so that the prestress is effectively applied to the cross section. You can
Moreover, in the said embodiment, the case where the joining method of the precast member of this invention and the adjustment member 3 were employ|adopted in the floor slab renewal business using the precast floor slab 1 was demonstrated. The member to which 3 can be applied is not limited to the floor slab. For example, the joining method of the precast member and the adjusting member of the present invention may be adopted in the joining portion between the box girders made of precast.

1 Precast floor slab (precast member)
14 First joining floor slab 15 Second joining floor slab 16 General floor slab 2 Formwork 3 Adjusting member 4 Demolding jig 5 Temporary fixing jig 6 Tilt adjusting member

Claims (6)

In a place other than the construction site, a plurality of precast members constituting a predetermined length range are temporarily placed, and a step of forming a cement-based material in the insufficient portion within the predetermined length range to form an adjusting member,
And a step of performing a connecting operation using the precast member and the adjusting member used for temporary placement at a construction site. A temporary placement step of temporarily placing a plurality of precast members in a place other than the construction site,
A method of joining precast members, comprising a main assembly step of main assembly of a plurality of the precast members at the construction site,
In the temporary placement step,
In a state where a gap is left between the end faces, a member temporary placement work for placing the pair of the precast members,
Formwork assembly work to install the formwork on the lower surface and the side surface of the gap,
A member forming operation of filling the clearance with a cement-based material to form an adjusting member,
Perform demolding work to demold the formwork,
In the main assembly process,
Member loading work for loading the precast member and the adjusting member to the construction site,
A method for joining precast members, comprising: connecting a pair of the precast members via the adjusting member. The joining method of a precast member according to claim 2, wherein, in the temporary member placement operation, another precast member is connected to an end surface of the precast member opposite to the gap side. The precast member joining method according to claim 2 or 3, wherein an angle of an end face of the precast member is adjusted in the temporary member placement operation. In the demolding operation, one of the pair of precast members is removed from the adjusting member,
The joining method of a precast member according to claim 2, wherein in the member carrying-in operation, the adjusting member is carried in while being attached to an end surface of the other precast member. .. In the joint portion of the precast members, a precast concrete adjustment member interposed between the precast members,
An adjusting member, wherein a butting surface with the precast member is formed by a match casting method, and has a shape capable of absorbing a manufacturing error or a construction error of the precast member.

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