JP2012225144A - Precast floor slab, joint structure and construction method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a precast floor slab which can reduce the amount of a gap filler substantially while supplementing the structural weak points sufficiently; and a joint structure and a construction method for the same.SOLUTION: A precast floor slab 1 comprises a body part and a joint end part, and the joint end part comprises a plurality of cutout parts 5 and a plurality of protrusions 4 formed by the cutout parts 5. The cutout parts 5 are formed by being cut out in a slab axial direction, and the protrusions 4 are respectively provided with a reinforcement 6 for joint protruding in the slab axial direction. The reinforcement 6 for joint may be an integral object with the structural reinforcements buried in the body part and the protrusions 4 or a separate object which is connected with the structural reinforcement, and when being arranged and connected at the time of connection with the other precast floor slab, the counterpart of connection, each protrusion 4 faces the cutout part 5 of the other precast floor slab of connection, and the cutout part 5 can house the reinforcement 6 for joint of the counterpart of connection, and the arrangement of reinforcement 6 for joint inside the cutout part 5 can secure a filling space for a gap filler.

Description

  The present invention relates to a bridge slab constructed by connecting a plurality of precast slabs, and more specifically, a precast slab having a joint end formed by a plurality of notches and projections. And its joint structure and construction method.

  In Japan, most of the country is occupied by mountainous areas, and because of the steep terrain, the current situation is that the roads developed in the country depend on many bridges. On the other hand, countless structures are densely populated in urban areas, and if a new road is planned there, it will depend on many bridges such as overpasses, overpasses and viaducts.

  Bridges are important structures, not to mention the social impact at the time of their damage, so they have been designed rigorously with long-established design standards such as `` Road Bridge Specification / Description '' and extremely high quality. It is constructed in. Thus, while high quality is required for the bridge, it has been required to be constructed more economically and with a shorter construction period due to social demands and improved technical capabilities.

  The slabs that make up the superstructure of the bridge are naturally installed at the time of new construction, but are also installed at the time of repairing existing bridges. As a result, the opportunity for replacement with high-value-added slabs is increasing.

  In the Showa 30s when the Tokyo Olympics were imminent, so-called construction rush was built, and many concrete structures were built. These concrete structures are now about 50 years old. The durability of concrete is said to be 50 years or 100 years, but this has not been verified yet, and if it is 50 years, many concrete structures in Japan, such as concrete floor slabs of bridges, need some kind of reinforcement measures. Will be. In fact, bridge inspections are currently being conducted mainly by local governments, and many concrete floor slabs have been found to have deteriorated or damaged. Under these circumstances, the existing bridge concrete slabs are being renovated.

  As mentioned above, rapid construction is required for bridge construction, and in the case of repair work for existing bridges, a short construction period is required. For example, viaducts on motorway roads such as expressways secure a huge amount of traffic to support the distribution industry in Japan, and it is strongly desired that construction be completed as soon as possible considering economic losses due to suspension of operation. .

  From the background described above, precast slabs are often used for bridge slabs. The cast-in-place concrete method that has been used in the past required a long period of construction, from concrete installation to concrete placement, but also because a precast floor slab was manufactured at the factory and can be easily installed. , The period of occupying the site is extremely short. Moreover, with the advancement of technology, the application range of precast slabs has been greatly expanded. For example, by adopting a steel / concrete composite slab type, long spans exceeding 10 m, curved bridges with a radius of 100 m or less, slanting with an angle of 45 ° It can be applied to bridges and the like, and the adoption of precast floor slabs has become easier to use.

  In general, “precast” refers to the production of concrete members in advance in places such as factories and production yards (including construction sites). The precast floor slabs are “precast floors”. Called "version".

  On the other hand, the precast floor slab involves a public road transport from the production site to the construction site, and therefore cannot be a very large member. Therefore, a plurality of precast floor slabs are arranged in the direction of the bridge axis (or the direction perpendicular to the bridge axis), and the precast floor slabs are connected to each other to complete the entire floor slab.

  When connecting a plurality of precast slabs, a so-called “joint” is provided between the precast slabs. There are two major problems with this joint. One is a structural problem and the other is a construction problem.

  The bridge slab is subjected to its own weight, loading load, and other impact loads, and as a result, a cross-sectional force (axial force, shearing force, bending moment) is generated in the slab. If the entire floor slab is constructed as an integral structure (for example, by a cast-in-place concrete method), the entire member bears a load, and the cross-sectional force does not concentrate at any location. On the other hand, when a bridge slab is constructed by connecting precast slabs, the joint location becomes a weak point in the structure, and there is a possibility that shear force and bending moment may concentrate, which is a structural problem. It is.

  The precast floor slab has a great feature that enables rapid construction work, but if the connection work at the joint is troublesome, the effect of rapidness is reduced accordingly. However, in the conventional joints of precast floor slabs, reinforcement bars are placed, tension is applied by tensioning steel wires and bars, or they are adjoined by a special jig in order to compensate for the above structural problems. Various “joint reinforcement work” has been performed, such as fixing precast slabs or placing concrete or mortar at joints. As a result, the problem with construction is that rapid construction, which is a major feature of precast slabs, is not fully utilized. In particular, if the amount of concrete or mortar to be placed at the joint location is large, the time allocated for the placement will greatly affect the entire construction period.

  In order to solve the structural problem, conventionally, the precast slabs are connected by the following method. At the end of the precast floor slab, there are joint reinforcing bars that project structural reinforcing bars (main reinforcing bars and distribution bars), and the joint reinforcing bars of both precast floor slabs to be connected are overlapped. They were connected with cable ties. When superimposing both reinforcing bars, the fixing length requires a predetermined length (more than 30 times the reinforcing bar diameter D), so the reinforcing bars must protrude from the precast floor slab with a length of 30D or more. In other words, both precast slabs to be connected must be arranged with an interval of 30D or more. For example, when the structural reinforcing bar is D22, the distance between the two precast slabs is about 700 to 800 mm, and mortar or concrete is placed in a space obtained by multiplying the 700 to 800 mm by the plate thickness.

  Although the structural problem can be solved by using the joint structure as described above, the amount of mortar placement becomes large, and one construction problem cannot be solved. Furthermore, because it is necessary to bind the reinforcing bars for joints of the precast floor slabs to be connected, a large deviation (error) between the reinforcing bars for both joints is not allowed, and the position (pitch) of the reinforcing bars during production and installation Strict precision control was required for placement.

  In order to solve the structural problem or the construction problem, the improvement technology related to the joint of the precast floor slab has been proposed so far. For example, in Patent Document 1, the volume of the concrete space to be placed in the “joint portion” is reduced. A joint structure has been proposed in which the construction period and cost are reduced by reducing the weight.

Japanese Patent Laid-Open No. 2004-324211

  However, the joint structure of the precast floor slab according to Patent Document 1 is to install a compression plate on the reinforcing bar in the precast floor slab. By sandwiching concrete between the compression plates of the adjacent precast floor slabs, originally, It is intended to load the bending tensile force generated in the reinforcing bar on the concrete as a compressive force. Therefore, the production of the factory for installing the compression plate and rib plate on the reinforcing bar becomes complicated, and in addition, the compression plate and rib plate arranged in a complicated manner are arranged at narrow joint locations (and the through holes provided in the rib plate). It is necessary to connect the adjacent precast floor slabs to each other, and the construction related to the joint is difficult and requires considerable construction time.

  The subject of the present invention is to solve the structural problem and the construction problem that the prior art has at the same time. Specifically, the amount of interlining material is reduced while sufficiently compensating for structural weaknesses. An object of the present invention is to provide a precast slab that can be significantly reduced, a joint structure and a construction method thereof.

  The precast slab of the present invention comprises a main body portion extending in the plate axis direction and a joint end portion provided at one end or both ends in the plate axis direction of the main body portion in a precast floor slab connected and used by a joint. The joint end portion includes a plurality of cutout portions and a plurality of convex portions formed by the cutout portions, and the cutout portions are formed by cutting out in the plate axis direction. Is provided with a joint rebar that protrudes in the plate axis direction, and the joint rebar connects a separate object to the structural rebar even if it is integral with the structural rebar embedded in the main body and the convex part. If the connected state is arranged when connecting to the other precast floor slab, each convex part faces the notch part of the other connected precast floor slab, and the notch part is for the other connecting joint. Can accommodate rebar, notched By placing the joint rebar inside, a filling space formed between the notch and the joint rebar or / and a space between the precast slabs to be connected can be filled with a filling material. It is what is done.

  In the precast floor slab of the present invention, the joint end portion is provided with reinforcing reinforcing bars arranged in the direction perpendicular to the printing plate axis and penetrating the convex portion and the notch portion, the joint reinforcing bar is provided with a connection tool, and the structural reinforcing bar is It is exposed to the end face of the convex part, and a connecting tool is provided at the exposed end part, and the connecting reinforcing bar can be attached to and detached from the structural reinforcing bar by the connecting tool of the connecting reinforcing bar and the connecting tool of the structural reinforcing bar. it can.

  In the precast floor slab of the present invention, each of the convex portions is provided with an opening that penetrates in the direction perpendicular to the plate axis with the upper surface open, and each of the openings is arranged in a row or substantially in a row in the direction perpendicular to the plate axis. In addition, the reinforcing reinforcing bars penetrating the protrusions and the notches can be accommodated.

  In the precast floor slab of the present invention, each of the convex portions is provided with a through-hole penetrating in the direction perpendicular to the plate axis, and each through-hole is arranged in one or substantially one row in the direction perpendicular to the plate axis. It is also possible to insert a reinforcing bar penetrating the notch.

  The precast floor slab of the present invention comprises a joint end at one or both ends in the plate axis direction of the main body, a convex portion and a notch are formed at the joint end, and the upper surface of the joint end is one step higher than the upper surface of the main body. A low paragraph and a part may be provided.

  The joint structure of the precast floor slab of the present invention connects a precast floor slab provided with a main body portion extending in the plate axis direction and joint end portions provided at one end or both ends of the main body portion in the plate axis direction. In the joint structure, the joint end portion of the precast floor slab includes a plurality of notches formed by being cut out in the plate axis direction, and a plurality of convex portions formed by the notches. The convex part is provided with a joint reinforcing bar that is connected to the main body part and the structural reinforcing bar embedded in the convex part and protrudes in the plate axis direction, and the convex part of the one precast floor slab to be connected is Opposite to the cutout portion of the other precast floor slab, the one other cutout portion accommodates the other coupling joint rebar, and by this arrangement, a filling space formed between the cutout portion and the joint rebar or / And concatenated Square during filling material into the gap between the precast slabs of a filled structure.

  The joint structure of the precast floor slab of the present invention is provided with reinforcing reinforcing bars arranged in a direction perpendicular to the printing plate axis and penetrating the convex part and the notch part, and provided with a connecting tool in the joint reinforcing bar and exposed to the end face of the convex part. A connecting tool is provided in the structural reinforcing bar, and the connecting reinforcing bar can be attached to and detached from the structural reinforcing bar by these connecting tools, and the connecting reinforcing bar is locked to the reinforcing reinforcing bar of one precast floor slab to be connected, It can also be set as the structure connected to the said structural reinforcement of the connected precast slab.

  In the joint structure of the precast floor slab of the present invention, an opening that is open on the top surface and penetrates in the direction perpendicular to the plate axis is provided in the convex portion, and each opening is arranged in one or substantially one row in the direction perpendicular to the plate axis. The opening may contain a reinforcing reinforcing bar penetrating the protrusion and the notch, and may be filled with a filling material.

  In the joint structure of the precast floor slab of the present invention, in the joint structure, a precast floor slab in which the upper surface of the joint end is formed one step lower than the upper surface of the main body and a section is provided is used. In addition, a structure in which a filling material is filled in the gap between the filling space and the two floor slabs from the injection space secured by the above-mentioned paragraphs of both precast floor slabs arranged to face each other can also be adopted.

  In the joint structure of the precast floor slab of the present invention, a tension member or a tension member arranged in a direction perpendicular to the plate axis and a reinforcing reinforcing bar are provided between one convex end face to be connected and the other convex end face to be connected. The tension member may be a structure to which a tension force is applied.

  The construction method of the precast floor slab joint of the present invention is a precast floor slab provided with a main body portion extending in the plate axis direction, and joint end portions provided at one end or both ends of the main body portion in the plate axis direction. In the method of connecting by a joint, the joint end portion of the precast floor slab includes a plurality of notches formed by notching in the plate axis direction, and a plurality of convex portions formed by the notches. The convex portion of the one precast slab is connected to the main body portion and the structural reinforcing rod embedded in the convex portion, and is provided with a joint reinforcing rod protruding in the plate axis direction. However, both the precast floor slabs are arranged so that the other connecting joint rebar is accommodated in one of the notches, and the joint is placed in the notch. Reinforcing bars are placed The gap between the notch and the filling space formed between the reinforcing bar fitting or / and connected by both precast slab by being a method of filling between filling material.

  The construction method of the precast floor slab joint of the present invention is such that the reinforcing bar which is arranged in a direction perpendicular to the plate axis and penetrates the convex part and the notch part is engaged with a loop-like joint reinforcing bar provided with a connector, and the joint Connecting the reinforcing bar for connecting to the connecting tool provided on the structural reinforcing bar exposed at the end face of the convex part and connecting the connecting reinforcing bar to the connecting reinforcing bar of the other precast slab You can also.

  In the method for constructing a precast floor slab joint of the present invention, the convex portion of the precast floor slab is provided with an opening penetrating in the direction perpendicular to the plate axis with the upper surface open, and each opening is in the direction perpendicular to the plate axis. It is also possible to adopt a method in which reinforcing reinforcing bars that are arranged in a line or substantially in a line and penetrate the convex part and the notch part are arranged in the opening part, and the filling material is filled.

  In the construction method of the precast floor slab joint of the present invention, both precast floor slabs are arranged so that a gap is provided between one convex end face to be connected and the other convex end face to be connected. A tension member may be disposed and the filling material may be filled, and after the filling material is cured, the tension member may be tensioned in a direction perpendicular to the plate axis to apply tension.

  The construction method of the precast floor slab joint of the present invention uses the precast floor slab provided with a paragraph and a section in which the upper surface of the joint end portion is formed one step lower than the upper surface of the main body in the precast floor slab. By placing both precast floor slabs to be connected opposite each other, the section is secured with an injection space that is one step lower than the top surface of the main body of the precast floor slab, and both fillers are injected into the injection space. It is also possible to use a method in which a filling material is filled into the filling space and the gap between the precast slabs. The joint reinforcing bar in the present invention can be formed in a loop shape.

The precast slab of the present invention, its joint structure and construction method have the following effects.
(1) Since the joint end portion is composed of a notch portion and a convex portion, the amount of the filling material to be filled in the joint portion is remarkably reduced. As a result, it is excellent in economic efficiency and the construction period for the construction of the floor slab. Can be greatly shortened.
(2) The notch is notched in the plate axis direction and is a small space, but it can be used to place joint rebars as well as to fill in filling materials. be able to.
(3) No special member is required, and it can be easily manufactured because it is completed only by cutting out a part of the floor slab.
(4) Since there is no need to bind the reinforcing bars for joints as in the prior art, the labor can be saved.
(5) Since it is only necessary to arrange the joint rebar at an arbitrary position in the notch, a certain amount of error is allowed when placing the precast floor slab, and the labor for manufacturing and construction is reduced.
(6) Since the amount of filling material filled is very small and the occurrence of cracks and the like accompanying shrinkage can be suppressed, there is no fear of structural deterioration.
(7) The filling space which is one step lower than the upper surface of the main body portion of the precast floor slab is secured by the paragraphs of the opposite connected precast floor slab, so that it becomes easy to fill the filling material. Since the injection space can be secured long (wide) in the plate axis direction, the upper surface of the filling material poured into the injection space can be finished flat, and the quality of the joint portion of the precast floor slab is improved.

(A) is the whole side view which shows the bridge in floor slab installation, (b) is the whole top view which shows the bridge in floor slab installation, (c) is the detail drawing of the D section shown in (b). The perspective view which shows the condition which installs a floor slab on a bridge girder. (A) is a plan view showing a first type of precast floor slab before being connected, (b) is a plan view showing a first type of precast floor slab in a connected state, and (c) is shown in (b). Sectional drawing of AA arrow, (d) is sectional drawing of BB arrow shown to (b). (A) is a plan view showing a second type of precast floor slab before being connected, (b) is a plan view showing a second type of precast floor slab in a connected state, and (c) is shown in (a). (A) is a sectional view taken along the line AA shown in (b), (e) is a sectional view taken along the line B'-B 'shown in (a), f) is a sectional view taken along line BB shown in (b). Detailed drawing of the connection tool provided in the reinforcing bar for joints and the structural reinforcing bar. (A) is a plan view showing a third type precast floor slab before being connected, (b) is a plan view showing a third type precast floor slab in a connected state, and (c) is shown in (b). Sectional drawing of AA arrow, (d) is sectional drawing of BB arrow shown to (b). (A) is a plan view showing a fourth type precast floor slab before being connected, (b) is a plan view showing a fourth type precast floor slab in a connected state, and (c) is shown in (b). Sectional drawing of AA arrow, (d) is sectional drawing of BB arrow shown to (b). The plane model figure in the case of connecting three precast floor slabs with one joint part. It is another Example of this invention, Comprising: The perspective view in the middle of the connection of the precast floor slab which made the joint edge part one step lower than the floor slab upper surface. Explanatory drawing of the state which filled the filling material in the injection | pouring space of FIG. (A) is a plan view of the precast floor slab in connection, (b) is a cross-sectional view taken along the line BB of (a), and (c) is a cross-sectional view taken along the line AA of the filling space of (a) filled with a filling material. Figure.

[Embodiment]
One embodiment of a precast floor slab of the present invention, a joint structure of a precast floor slab, and a method for constructing a precast floor slab joint will be described with reference to the drawings.

(overall structure)
FIG. 1 is a general view showing a bridge during installation of a floor slab, FIG. 1 (a) is a side view thereof, FIG. 1 (b) is a plan view thereof, and FIG. 1 (c) is a diagram shown in FIG. FIG. As shown in Fig. 1 (a), several precast floor slabs 1 are already arranged on the bridge girder 2 on this bridge, and another precast floor slab 1 is suspended by a lifting machine on the bridge girder 2. Is about to be installed. As shown in FIG. 2, the precast slab 1 is placed on two or more bridge girders 2 (three bridge girders 2 in the figure) and arranged in the bridge axis direction. Of course, in the case of a bridge with a wide road width, the precast floor slabs 1 may be arranged side by side in a direction perpendicular to the bridge axis.

  The precast floor slabs 1 arranged at predetermined positions on the bridge girder 2 are connected to other adjacent precast floor slabs 1. “Connected” here means that the independent precast floor slabs 1 are integrated together, specifically, the precast floor so that the cross-sectional force (axial force, shear force, bending moment) can be transmitted. It is to connect the plates 1 to each other. In this way, one precast floor slab 1 adjacent on the bridge girder 2 and the other precast floor slab 1 are sequentially connected to complete the entire bridge floor slab.

  As shown in FIG. 1A and FIG. 2, when the precast floor slab 1 is arranged on the bridge girder 2, the adjacent precast floor slab 1 is usually already arranged on the bridge girder 2. 1 are arranged in a predetermined positional relationship. For example, as shown in FIG. 1B, a gap N can be provided between the two precast slabs 1 to be connected. Both precast slabs 1 can be placed in contact with each other, but in this case, a minute gap may occur due to the effects of manufacturing errors and installation errors. desirable. In addition, since this gap N is filled with a filling material such as mortar, the interval is set to a width in which mortar or the like can be placed (for example, 30 mm or more). Hereinafter, two precast floor slabs 1 arranged adjacent to each other for connection are referred to as “both precast floor slabs 1”, one of “both precast floor slabs 1” is “one precast floor slab 1”, and the rest Is referred to as “the connected precast slab 1”. In addition, a state where both precast floor slabs 1 are placed in a predetermined arrangement for connection is referred to as a “connected state”.

  Both the precast floor slabs 1 arranged in a connected state face each other (opposite) to form a joint point P shown in FIG. In this joint location P, both the precast floor slabs 1 are connected by arranging the reinforcing bars for joints described later and filling the filling material.

  As described above, the precast floor slabs 1 are arranged on the bridge girder 2 and both the precast floor slabs 1 in the connected state are connected at the joint point P. By repeating this in sequence, the entire bridge deck is completed. 1 (a) to 1 (c) and FIG. 2 show a simple beam type bridge, the present invention is not limited to this but can be implemented in any structural type (multi-span type). Moreover, although the joint structure in the case of connecting the precast floor slab 1 in the bridge axis direction is described here, the present invention is similarly implemented even when the precast floor slab 1 is connected in the direction perpendicular to the bridge axis. be able to.

  Hereinafter, each component will be described in detail.

(Precast floor slab)
The precast floor slab 1 is manufactured in advance (before the installation of the floor slab) in places such as factories and manufacturing yards (including construction sites). Reinforcing bar 3 ”(see FIG. 3C) and concrete. The precast slab 1 of the present invention includes precast slabs of any structure conventionally used, including those of RC (Reinforced Concrete) and PC (Prestressed Concrete).

  As shown in FIG. 2, the general precast floor slab 1 has a plate shape that is generally rectangular in plan view and relatively thin. Since the precast floor slab 1 is bridged over the bridge girder 2, the bridge girder 2 direction (bridge axis direction) can be set to any size, but the dimension in the direction perpendicular to the bridge axis is limited by the distance between the bridge girder 2 and is The planar shape has a short side in the axial direction and a long side in the direction perpendicular to the bridge axis. If the planar shape of the precast floor slab 1 is illustrated, it can be made into a rectangle with a long side of 5 to 10 m and a short side of 1 to 3 m. Of course, the present invention is not limited to such a shape, but for the sake of convenience, the present embodiment will be described in the case where the planar shape of the precast floor slab 1 is rectangular. For the following description, as shown in FIG. 1B, two axes are provided on the plane of the precast floor slab 1, one axis is defined as “plate axis direction”, and the other axis is defined as “plate axis perpendicular direction”. And The plate axis direction is a direction in which the other precast floor slab 1 is placed in the connected state, and in this embodiment, is the short side direction of the precast floor slab 1 as shown in FIG. The plate axis perpendicular direction is literally the direction perpendicular to the plate axis direction, and in this embodiment, is the long side direction of the precast floor slab 1 as shown in FIG. That is, when the precast floor slab 1 is connected in the bridge axis direction, the plate axis direction and the bridge axis direction coincide with each other in the connected state, and the plate axis perpendicular direction and the bridge axis perpendicular direction coincide with each other.

  The precast floor slab 1 includes a main body portion and a joint end portion. As shown in FIG. 1 (b), the joint end is provided on the end side in the plate axis direction of the precast floor slab 1. As shown in FIG. 1 (c), the protrusion 4 and the notch Part 5 is formed. And the part which becomes a main body in the part except a joint edge part among the precast slabs 1 is a main-body part. The joint ends are provided at both ends (plate axis direction) or one end of the precast floor slab 1. For example, as shown in FIG. 1 (b), the precast floor slab 1 (the left end in the figure) arranged at the end of the bridge floor slab is provided with a joint end only on one end side, and is arranged in the middle of the span and on both sides. The precast slab 1 to be connected may be provided with joint ends on both sides. Depending on the case (when connecting also in the direction perpendicular to the plate axis), joint ends can be provided on three or four sides of the rectangle.

(Fitting end)
As shown in FIG.1 (b), the some convex part 4 and the notch part 5 are repeatedly arrange | positioned at the joint edge part. As shown in FIG. 1C, the notch 5 is cut out in the plate axis direction from the plate shaft end (the end surface of the plate, the right end in the figure), and has a substantially rectangular shape. As will be described later, a joint reinforcing bar is disposed in the notch 5 and is filled with a filling material. Therefore, as long as a space necessary for this can be secured, the notch 5 can be formed in an arbitrary shape. A plurality of the notches 5 are formed at intervals in the direction perpendicular to the printing plate axis, and the portion that remains without being notched is the protrusion 4, in other words, the protrusion 4 is provided with the notch 5. It is formed with.

  The precast floor slab 1 of the present invention has various types in the arrangement method of the joint reinforcing bars 6 (FIG. 3A) and the mounting method of the reinforcing reinforcing bars 7 (FIG. 4A), which will be described later. There are various types of joint structures and construction methods. FIG. 3 is an explanatory view showing the first type precast floor slab 1 among them, and FIG. 3 (a) is a plan view showing the first type precast floor slab 1 before being connected, FIG. ) Is a plan view showing the first type precast slab 1 in a connected state, FIG. 3C is a cross-sectional view taken along the line AA in FIG. 3B, and FIG. It is sectional drawing of the BB arrow shown to b).

  As shown in FIG. 3A, the protrusion 4 is provided with a joint reinforcing bar 6. As shown in FIGS. 3 (c) and 3 (d), the structural rebar 3 is disposed over the main body and the convex part 4, and further protrudes from the end face of the convex part 4, and this protruding part is the joint reinforcing bar 6. . That is, the joint rebar 6 shown in this figure is a part of the structural rebar 3, but here, the protruding portion will be described as the joint rebar 6 for convenience. In addition, as will be described later, the joint reinforcing bar 6 can be separated from the structural reinforcing bar 3, and in this case, the structural reinforcing bar 3 embedded in the precast floor slab 1 (main body part and convex part 4) It is necessary to connect the joint reinforcement 6. In short, the joint rebar 6 protrudes from the end face of the convex portion 4 in the plate axis direction (outside) and can be in various forms as long as it is connected to the structural rebar 3.

  Further, as shown in FIGS. 3C and 3D, the joint reinforcing bar 6 may be formed in a loop shape (U-shape). In the case of the present invention, the length of the reinforcing bar 6 for the joint can be shortened, and the size of the notch portion 5 (the notch length) can be shortened because the fixing length of the reinforcing bar can be shortened when the loop shape is used. ) Is also reduced, and as a result, the filling amount of the filling material can be reduced, which is preferable.

  As shown in FIG. 3 (b), when both the precast floor slabs 1 to be connected are in a connected state, as shown in FIGS. 3 (c) and 3 (d), one of the precast floor slabs 1 (for example, the left side of the figure) The convex part 4 faces the notch part 5 of the connected precast floor slab 1 (for example, the right side of the figure) (hereinafter referred to as “opposing”). Similarly, the cutout portion 5 of one precast floor slab 1 faces the convex portion 4 of the connected other precast floor slab 1. For this reason, when providing joint ends at both ends of the precast floor slab 1, the arrangement of the notches 5 and the protrusions 4 at one joint end is different from the arrangement at the other joint end. That is, when an arbitrary plate axis direction line is drawn on the precast floor slab 1, for example, the convex portions 4 are arranged at the right end portion, and the notches 5 are arranged at the left end portion.

  In the connected state, as shown in FIG. 3B, the joint rebar 6 provided on the convex portion 4 of the one precast floor slab 1 is accommodated in the notch portion 5 that faces the joint. That is, the notch length of the notch portion 5 (the length notched in the plate axis direction from the plate shaft end) is the distance between the gaps N (FIG. 1 (b)) provided in the connected state and the length of the joint reinforcing bar 6. Designed to suit your needs.

  When connecting both the precast floor slabs 1, the interstitial material 16 is filled in the gaps N provided between the notches 5 and the precast floor slabs 1. Therefore, the notch 5 needs a space (filling space) for filling the filling material 16 and needs to be notched with a predetermined notch width (dimension in the direction perpendicular to the plate axis). For example, when the stuffing material is mortar, the notch width of the notch 5 is preferably 30 mm or more. In addition, the notch width of the notch part 5 is usually larger than the reinforcing bar diameter of the joint rebar 6, that is, the joint rebar 6 has a margin in the width direction in the notch part 5, and thus the joint rebar 6 in the manufacturing process. There is an effect that it is possible to absorb the bar arrangement error and the arrangement error when the precast floor slab 1 is installed.

  As described above, when both the precast floor slabs 1 are connected, the joint rebar 6 of one precast floor slab 1 is accommodated in the notched part 5 of the other precast floor slab 1 and filled into the notched part 5. The padding material 16 is cured and fixed. Considering that the joint rebar 6 is connected to the structural rebar 3 embedded in the precast floor slab 1 (FIGS. 3C and 3D), the joint rebar 6 is accommodated in the notch 5. This means that the structural rebar 3 of one precast floor slab 1 is fixed to the connected other precast floor slab 1. Conventionally, both the precast floor slabs 1 are connected by projecting the structural reinforcing bars 3 from both the precast floor slabs 1 and integrating them with a binding wire. On the other hand, in this invention, both the precast floor slabs 1 are connected by making the reinforcing bar 6 for joints squeeze into the other precast floor slab 1 so to speak. In other words, conventionally, it has been necessary to provide a space between the two precast slabs 1 by the fixing length of the reinforcing bar (30 times or more of the reinforcing bar diameter D) and to fill the filling material 16 therewith. There is no need to provide such an interval. Therefore, the present invention can remarkably reduce the filling amount of the filling material as compared with the conventional case, and is advantageous in terms of construction such as cracking of the filling material, economics such as material cost, construction labor and construction time. There is an effect.

(Filling material)
As described above, after the joint rebar 6 is accommodated in the notch 5, the filling space 14 formed between the notch 5 and the joint rebar 6 and the gap N provided between the two precast slabs 1 in a connected state. Is filled with a filling material 16. Generally, mortar is used for the filling material 16, but concrete, fiber reinforced mortar, polymer mortar, or the like may be adopted depending on the situation.

  From the viewpoint of rapid construction, it is desirable that the time required for curing the interlining material to be used is short. For example, if ultrafast hard mortar is used, strength can be expected to withstand use within about one hour after filling, which is preferable. In addition, if mortar reinforced with short fibers is used, the tensile strength is increased and crack resistance and deformation performance are improved, which is further preferable.

(Reinforcing bar)
FIG. 4 is an explanatory view showing a second type of precast floor slab 1. FIG. 4 (a) is a plan view showing the second type of precast floor slab 1 before being connected, and FIG. FIG. 4C is a plan view showing the second type precast slab 1 in a connected state, FIG. 4C is a cross-sectional view taken along the arrow A′-A ′ shown in FIG. 4A, and FIG. 4A is a cross-sectional view taken along the line AA shown in FIG. 4B, FIG. 4E is a cross-sectional view taken along the line B′-B ′ shown in FIG. 4A, and FIG. 4F is shown in FIG. It is sectional drawing of a BB arrow. As shown in these drawings, the reinforcing bars 7 arranged in the direction perpendicular to the plate axis can be installed at the joint point P (FIG. 1A). The joint point P, which was originally a structural weak point, is suitable because it is further reinforced by installing this reinforcing bar 7.

  As shown in FIGS. 4 (a) and 4 (b), the reinforcing reinforcing bars 7 are arranged in a direction perpendicular to the printing plate axis, so that they are installed so as to penetrate the convex portions 4 and the cutout portions 5 at the joint ends. In this case, the reinforcing reinforcing bar 7 can be fixed to the precast floor slab 1 so as to penetrate the convex part 4 and the notch part 5 in the process of manufacturing the factory, and an opening part is provided in the convex part 4 as will be described later. Thus, the reinforcing steel bars 7 can be installed on site (installation site of the precast floor slab 1). In addition, the reinforcing bars 7 can be installed in the gaps N (FIG. 1B) provided in a connected state.

(Tension member)
As shown in FIGS. 3 (b) to 3 (c), instead of (or in addition to) the reinforcing steel bars 7, the tension members 8 can be installed at the joint points P (FIG. 1 (a)). As the tension material 8, PC steel material can be exemplified, but various materials can be used as long as they can introduce pre-stress (tension force) by a so-called post-tension method in which tension is applied and tension is applied locally. can do. In order to install the tendon material 8, it is necessary to provide a gap N (FIG. 1 (b)) between the two precast slabs 1 in the connected state. A sheath tube is arranged in advance in the gap N, and the tension member 8 is inserted into the sheath tube, and the interstitial material 16 is filled. Then, after the filling material 16 is cured (for example, 1 hour after filling in the case of a super-hard hard mortar), both ends of the tension material 8 are tensioned in the direction perpendicular to the plate axis, and in this state, the grout is injected into the sheath tube and fixed. Apply prestress by wearing tools.

  It is also possible to use a pre-grout PC steel material that does not require a sheath tube. In this case, installation of the sheath tube and injection of grout into the sheath tube can be omitted, and the hardening time of the grout can be shortened. .

(Type of precast floor slab)
As described above, the precast floor slab 1 of the present invention has various types in how to attach the reinforcing bars 6 and the reinforcing bars 7 for the joints, and accordingly, there are various types in the joint structures and construction methods. To do. Here, the type of the precast floor slab 1 will be described.

  The precast floor slab 1 shown in FIGS. 3A to 3D is the first type. The joint rebar 6 is a series of structural rebars 3 and has a U-shape. In the connected state (FIG. 3B), a gap N (FIG. 1B) is provided between the two precast slabs 1, and a tension member 8 is installed here. Of course, instead of (in addition to) this tendon member 8, a reinforcing steel bar 7 can be installed.

  The precast floor slab 1 shown in FIGS. 4A to 4F is the second type. The joint rebar 6 is U-shaped as in the first type, but is characterized by being separate from the structural rebar 3 and detachable. In addition, a reinforcing reinforcing bar 7 is installed at the joint end so as to penetrate the convex portion 4 and the cutout portion 5. As shown in FIG. 5 (only one end of the joint rebar 6 is shown in the figure for convenience), couplers 9a (connectors) are fixedly provided at both ends of the joint rebar 6. Further, as shown in FIG. 5, a coupler 9b (connector) is also fixedly provided on the structural reinforcing bar 3. The coupler 9a fixed to the joint reinforcing bar 6 and the coupler 9b fixed to the structural reinforcing bar 3 are brought into contact with each other, and both are connected by a connecting screw 9c. In some cases, the joint rebar 6 once connected to the structural rebar 3 can be removed. Instead of the connecting screw 9c, a connecting screw 9d with an intermediate nut can be used.

  The second type joint rebar 6 is connected and fixed to the structural rebar 3 on site (installation site of the precast floor slab 1). At this time, the joint reinforcing bar 6 is fixed to the structural reinforcing bar 3 after being engaged with the reinforcing reinforcing bar 7 of the other precast floor slab 1 connected. Therefore, if it can be locked to the reinforcing bar 7 at the site, the joint reinforcing bar 6 can be carried in separately from the precast floor slab 1, but if it cannot be locked to the reinforcing bar 7 at the site, It is necessary to carry in the joint rebar 6 in a state of being locked to the reinforcing rebar 7. Specifically, as shown in FIGS. 4 (a) to 4 (f), the joint reinforcing bars 6 that are locked in advance with the reinforcing reinforcing bars 7 and carried together with the precast floor slab 1 are in a connected state (FIG. 4B ( In (d) and (f)), it is connected and fixed to the structural reinforcing bar 3 of the other precast slab 1 (FIGS. 4 (c) to (d) and FIGS. 4 (e) to (f)).

  The precast floor slab 1 shown in FIGS. 6A to 6D is the third type. FIG. 6A is a plan view showing a third type precast floor slab 1 before the connected state, FIG. 6B is a plan view showing the third type precast floor slab 1 in a connected state, and FIG. FIG. 6C is a sectional view taken along the line AA shown in FIG. 6B, and FIG. 6D is a sectional view taken along the line BB shown in FIG. 6B. Similar to the first type, the joint rebar 6 is a series of structural rebars 3 and has a U-shape. A characteristic feature is that an opening 10 (slit) penetrating in the direction perpendicular to the plate axis with the upper surface open is provided in the convex portion 4 at the joint end.

  The opening 10 provided in the third type is for installing the reinforcing bar 7 and, of course, has a space in which the reinforcing bar 7 can be arranged. At the same time, the openings 10 provided in the plurality of convex portions 4 constituting one connecting end are arranged so as to be arranged in approximately one row (including one row) so that the reinforcing reinforcing bars 7 can be arranged. If an example of the installation procedure of the reinforcing bar 7 is shown, first, both precast floor slabs 1 are arranged in a connected state (FIGS. 6B to 6D), and the reinforcing bar 7 is lowered from above the opening 10. It is installed at a predetermined position in the opening 10. At this time, a spacer can be installed in the opening 10 to adjust the installation height. Thereafter, a filling material is filled into the opening 10. In addition, although the opening part 10 can also be made into the through-hole which penetrates each convex part 4 without making upper part open, when it considers the ease of filling of a filling material, it is better to make it upper part open.

  A precast floor slab 1 shown in FIGS. 7A to 7D is a fourth type, which is a modification of the third type. FIG. 7A is a plan view showing a fourth type of precast floor slab 1 before being connected, FIG. 7B is a plan view showing a fourth type of precast floor slab 1 in a connected state, and FIG. FIG. 7C is a cross-sectional view taken along the line AA shown in FIG. 7B, and FIG. 7D is a cross-sectional view taken along the line BB shown in FIG. 7B. Similar to the first type, the joint rebar 6 is a series of structural rebars 3 and has a U-shape, but is embedded in the convex portion 4. Further, in the convex portion 4 at the joint end portion, an opening 10 penetrating in the direction perpendicular to the printing plate axis is provided in the same manner as in the third type. Then, two openings 10 are provided.

  The fourth type is characterized in that the convex portion 4 provided with the joint reinforcing bar 6 is accommodated in the facing notch portion 5. That is, by inserting the joint rebar 6 together with the convex portion 4 into the other precast floor slab 1, the joint rebar 6 is fixed. In addition, although each opening part 10 provided in the some convex part 4 which comprises one connection edge part is arrange | positioned so that it may be located in a line (a line is also included), it is the same as that of a 3rd type. Since the convex part 4 is accommodated in the notch part 5 which opposes, as shown in FIG.7 (b), the opening part 10 provided in the connection other convex part 4 is also located in a line in a connection state. Has been placed. Thus, since both the opening parts 10 provided in both the precast floor slabs 1 in the connected state are arranged so as to be arranged in substantially one row, the reinforcing reinforcing bars 7 can be easily installed. In addition, when two openings 10 are provided in one convex part 4, both openings 10 arranged in a substantially line are provided in two places as shown in FIG. Reinforcing bars 7 are respectively installed in two series of openings 10.

  The precast floor slab 1 shown in FIG. 9 is the fifth type. The precast floor slab 1 includes a joint end 12 at one or both ends of the main body 11 having a flat upper surface in the plate axis direction, and convex portions 4 and notches 5 are alternately formed in the joint end 12 in a direction perpendicular to the plate axis. In addition, the upper surface of the joint end portion 12 (the upper surface of the convex portion and its root side) is made one step lower than the upper surface of the main body portion 11 to form a section 13.

  When connecting the precast floor slab 1 of FIG. 9, the joint rebar 6 protruding from the convex part 4 of one precast floor slab 1 arranged opposite to each other is disposed in the notch part 5 of the other precast floor slab 1. Then, both or either one of the reinforcing reinforcing bars 7 and the tension members 8 are inserted in the direction perpendicular to the plate axis, and the convex portion 4 and the notch portion 5 are penetrated. With this arrangement, as shown in FIG. 9, a filling space 14 in which the filling material 16 can be filled in the notch 5 is secured, a gap N is secured between the precast floor slabs 1, and the opposing precast floor slabs 1 face each other. As a result, a one-step lower injection space 15 between the portions 13 is formed. A filling material 16 can be poured into the filling space 15 as shown in FIG. 10, and the filling material 16 can be filled into the filling space 14 and the gap N as shown in FIG. In this case, since the injection space 15 (FIG. 9) is secured long (wide), it becomes easy to inject the filling material, and the upper surface of the filling material 16 in the injection space 15 can be finished smoothly, and the precast slab The quality of the joint part can be improved.

(Construction procedure)
An example of the installation procedure of the precast floor slab 1 of this invention and the construction procedure of the joint structure of the precast floor slab 1 is shown.
The precast slab 1 suspended by a lifting machine is lowered onto the bridge girder 2 already constructed. At this time, in order for the convex part 4 of one precast floor slab 1 to oppose the other notch part 5 of a connection, and so that the connection other rebar 6 may be accommodated in one notch part 5 beforehand. Arranged at the specified surveyed position. In addition, when the clearance gap N is obtained between both the precast floor slabs 1, the precast floor slab 1 is installed at a predetermined interval in the plate axis direction.
After both the precast floor slabs 1 are in the connected state in this way, in the case of the type 2, the U-shaped joint reinforcing bar 6 is locked to one reinforcing reinforcing bar 7, and then the connector (coupler 9a, 9b). ) To fix the connected structural rebar 3.
In the case of type 3 or type 4, the reinforcing reinforcing bars 7 are installed in the opening 10 provided in the convex part 4.
Thereafter, the filling material 16 is filled into the notch 5 (filling space), the gap N, and the opening 10 in which the joint reinforcing bars 6 are accommodated. When the interlining material 16 is cured, the connection of both the precast floor slabs 1 is completed.
When the tensioning material 8 is installed, both ends of the tensioning material 8 are tensioned in the direction perpendicular to the plate axis after the filling material 16 is cured, and a pre-stress (tensioning force) is introduced by attaching a fixing tool in that state. To do.

[Other Embodiments]
The precast floor slab of the present invention and its joint structure and construction method are not limited to the case where two precast floor slabs 1 are butted and connected to each other, and as shown in FIG. Even when the plate 1 (three in FIG. 8, 1a, 1b, and 1c) is connected, it can be used. Even in this case, the structure, joint structure, and construction method of the precast slab 1 are the same as those in the above-described [Embodiment].

  The precast slab of the present invention, its joint structure and construction method can be used for various bridges such as road bridges, railway bridges, river bridges and viaducts, as well as segments used in city tunnel shield construction methods, It can be applied in all fields, such as precast plates for earth retaining used for deep earth retaining works, or box culverts with large sections.

1 Precast floor slab 1a First precast floor slab (when three are connected) 1b Second precast floor slab (when three are connected) 1c Third precast (when three are connected) Floor slab 2 Bridge girder 3 Structural reinforcing bar 4 Convex part 5 Notch 6 Reinforcing bar 7 Reinforcing bar 8 Tension material 9a Coupler (connecting bar) coupler
9b Coupler (structural rebar)
9c Connecting screw 10 Opening (slit)
DESCRIPTION OF SYMBOLS 11 Main part of precast floor slab 12 Joint end part 13 of precast floor slab Paragraph 14 Filling space 15 Injection space 16 Filling material N Crevice P Joint location

Claims (15)

In precast slabs that are connected by joints,
A main body portion extending in the printing plate axis direction, and a joint end portion provided at one or both ends of the printing plate axis direction of the main body portion,
The joint end includes a plurality of notches and a plurality of convex portions formed by the notches,
The notch is formed by being cut in the plate axis direction,
The protrusion is provided with a joint rebar that protrudes in the plate axis direction,
The joint rebar may be an integral part of the structural rebar embedded in the main body and the convex part or may be a separate object connected to the structural rebar,
When connected to the other precast floor slab, the projections face the notch of the other precast floor slab, and the notch can accommodate the joint rebar for the other joint. Yes, by providing a joint rebar in the notch, a filling space formed between the notch and the joint rebar or / and a gap between both precast slabs connected can be filled with a filling material. A precast floor slab characterized by ensuring a filling space. In the precast slab of claim 1,
The joint end is provided with a reinforcing steel bar that is arranged in a direction perpendicular to the plate axis and penetrates the convex part and the notch part,
The joint rebar is provided with a connector,
The structural reinforcing bar is exposed at the end face of the convex part, and a connection tool is provided at the exposed end part.
The precast floor slab, wherein the joint reinforcing bar is detachable from the structural reinforcing bar by the joint reinforcing bar connector and the structural reinforcing bar connector. In the precast slab of claim 1 or claim 2,
Each of the convex portions is provided with an opening that penetrates in the direction perpendicular to the plate axis with the upper surface open,
Each of the openings is arranged in one row or substantially in a row in a direction perpendicular to the plate axis, and can accommodate a reinforcing bar penetrating the convex portion and the cutout portion. In the precast slab of claim 1 or claim 2,
Each of the convex portions is provided with a through-hole penetrating in the direction perpendicular to the plate axis, and each through hole is arranged in a row or substantially in a row in the direction perpendicular to the plate axis, and a reinforcing reinforcing bar penetrating the convex portion and the notch portion is provided. A precast floor slab that can be inserted. In the precast floor slab according to any one of claims 1 to 4,
A joint end is provided at one or both ends in the printing axis direction of the main body part, and a convex part and a notch part are formed at the joint end part, and the upper surface of the joint end part is provided with a section that is one step lower than the upper surface of the main body part. Precast floor slab characterized by that. In the joint structure for connecting the precast floor slabs provided with a main body portion extending in the plate axis direction, and joint end portions provided at one or both ends in the plate axis direction of the main body portion,
The joint end of the precast floor slab has a plurality of notches formed by being cut out in the plate axis direction, and has a plurality of protrusions formed by the notches, A reinforcing bar for a joint that is connected to a structural reinforcing bar embedded in the main body part and the convex part and protrudes in the plate axis direction is provided;
The convex portion of the one precast floor slab to be connected is opposed to the notch of the other precast floor slab to be connected,
One of the cutouts accommodates the other connecting joint rebar, and this arrangement provides a space between the cutout and the joint reinforcing bar or / and a gap between the two precast slabs to be connected. A joint structure of a precast floor slab, characterized by being filled with a filling material. In the joint structure of the precast slab according to claim 6,
Reinforcing bars that are arranged in the direction perpendicular to the printing plate axis and penetrate the convex and notched portions are provided,
The connection rebar is provided with a connection tool, and the connection rebar is provided with a structural rebar exposed on the end face of the convex portion. With these connection tools, the connection rebar is detachable from the structural rebar,
The joint structure of a precast floor slab, wherein the joint reinforcing bar is locked to the reinforcing reinforcing bar of one precast floor slab to be connected and connected to the structural reinforcing bar of the other precast floor slab. . In the joint structure of the precast floor slab according to claim 6 or 7,
Openings penetrating in the direction perpendicular to the plate axis with the upper surface open are provided in the convex portion, and the respective openings are arranged in a row or substantially in a row in the direction perpendicular to the plate axis,
A joint structure for a precast floor slab, characterized in that a reinforcing reinforcing bar penetrating the convex portion and the notch portion is accommodated in the opening portion, and a filling material is filled therein. In the joint structure of the precast slab according to any one of claims 6 to 8,
In the precast floor slab, a precast floor slab is used in which the upper surface of the joint end is formed one step lower than the upper surface of the main body, and a section is provided. A joint structure for a precast slab, characterized in that a filling material is filled in a gap between a filling space and a filling space and both floor slabs. In the joint structure of the precast floor slab according to any one of claims 6 to 9,
A tension member disposed in a direction perpendicular to the printing plate axis is provided between one convex end face to be connected and the other convex end face to be connected.
A joint structure for a precast floor slab, wherein a tension force is applied by the tension member. In a method of connecting the precast floor slabs provided with a main body portion extending in the plate axis direction and joint end portions provided at one end or both ends in the plate axis direction of the main body portion by a joint,
The joint end of the precast floor slab has a plurality of notches formed by being cut out in the plate axis direction, and has a plurality of protrusions formed by the notches, A reinforcing bar for a joint that is connected to a structural reinforcing bar embedded in the main body part and the convex part and protrudes in the plate axis direction is provided;
Both of the protrusions of one of the precast slabs to be connected are opposed to the other notch of the connection, and the other of the joint reinforcing bars is accommodated in one of the notches. Place the precast floor slab,
Filling the filling space formed between the notch 5 and the joint rebar 7 by arranging the joint reinforcing bar in the notch or / and the gap between the two precast slabs connected to each other. The construction method of the precast floor slab joint characterized by the above-mentioned. In the construction method of the precast floor slab joint according to claim 11,
Lock the reinforcing bar for the joint in which the connection tool is provided to the reinforcing bar that is arranged in the direction perpendicular to the plate axis and penetrates the convex part and the notch part,
Connecting the joint rebar to a connector provided on the structural rebar exposed at the end face of the convex portion;
A construction method for a precast floor slab joint, characterized in that one rebar for joint to be connected and the structural rebar of the other precast floor slab to be connected are connected. In the construction method of the precast floor slab joint according to claim 11 or claim 12,
The convex part of the precast floor slab is provided with openings that are open on the upper surface and penetrated in the direction perpendicular to the plate axis, and each opening is arranged in a row or substantially in a row in the direction perpendicular to the plate axis,
The construction method of the precast floor slab joint characterized by arrange | positioning the reinforcing reinforcing bar which penetrates a convex part and a notch part in the said opening part, and filling a filling material. In the construction method of the precast floor slab joint according to any one of claims 11 to 13,
Place both precast floor slabs so that a gap is provided between one convex end face to be connected and the other convex end face to be connected,
In the gap, a tension member is disposed and a filling material is filled,
The construction method of the precast floor slab joint characterized in that, after the filling material is cured, the tension member is tensioned in a direction perpendicular to the plate axis to impart tension. In the construction method of the precast floor slab joint according to any one of claims 11 to 14,
Use a precast floor slab with a precast floor slab that has a section with the upper surface of the joint end one step lower than the upper surface of the main body. The section secures an injection space one step lower than the upper surface of the main body of the precast floor slab, injects a filling material into the injection space, and fills the filling space and the gap between the two precast floor slabs. The construction method of the precast floor slab joint characterized by the above-mentioned.

Images