JP4258021B2 - Precast concrete slab for prestressed concrete floorboard - Google Patents

Description

    The present invention relates to a precast concrete slab for a prestressed concrete floorboard that can be used as a floorboard for a portion that receives a heavy load locally, such as a runway or a passage of a large aircraft at an airport, a passage where a gantry crane for unloading travels at a wharf, and the like.

    Conventionally, precast concrete plates (hereinafter referred to as PCaC plates) have been used as floor boards for buildings, elevated roads, piers, and the like. For these PCaC plates, rectangular prestressed concrete plates (hereinafter referred to as PC plates) in which tension materials are arranged in the vertical and horizontal directions to be used are used.

    This type of conventional PCaC plate to which prestress is applied is structurally in which the generated cross-sectional force (mainly bending moment) is supported on four sides, that is, the load applied downward on the surface is supported on the four sides of the PCaC plate. Is the smallest. In this case, when a downward load is applied to the upper surface of the PCaC plate, the same cross-sectional force is generated in both XY directions.

    For this reason, conventionally, the PCaC plate has a structure in which prestress is applied in the direction between two opposing sides (see, for example, Patent Documents 1 and 2).

Further, in such a PCaC plate, the bending moment generated when a downward load is applied to the surface is the largest in the central portion and decreases as it reaches the peripheral portion. Even if the tension force of the tendon material was partially increased, this had an effect on the whole, and it was not possible to introduce a large prestress partially. For this reason, conventionally, prestress is uniformly introduced in the entire region in accordance with the largest bending moment generated in the central portion.
JP-A 64-4307 JP-A-63-107638

    The conventional PCaC version as described above is sufficient when it is used in a place where an extremely heavy load of 600 tons is applied locally, such as an airport runway, an aircraft passage, and a gantry crane passage at a wharf. In order to obtain a load resistance, the overall plate thickness must be increased and a large prestress must be introduced over the entire plane, and the weight of the PCaC plate itself becomes extremely large, resulting in difficulty in handling. In addition, there is a problem that it requires high technology, many materials such as PC tension material and concrete, and advanced equipment for introducing prestress, which inevitably leads to high cost. For example, 10m square PCaC A plate that can withstand a heavy load of 500 to 800 t has not been seen in the past.

    In addition, when a large area PCaC plate is used in a place where a large load is applied locally, if the local load acts on a part that is deviated from the center, the plate itself is warped, and the corners are raised. Each time an aircraft or crane passes, the corners will lift and vibrate, creating a step between adjacent plates. To prevent this, the four corners of the PCaC plate and the lower support structure below it There is a problem that it is necessary to strengthen the connection between the two, which requires advanced technology and expensive materials.

    Furthermore, in order to solve the above-mentioned problems of the prior art, a diagonally high rigidity portion having rigidity greater than the surroundings is provided between the diagonals of the rectangular precast concrete plate body in a continuous arrangement, and the diagonally high rigidity is provided. A PCaC plate has been developed in which a PC tension material is inserted into the part. In this PCaC plate, when the PCaC plate is rectangular, the magnitude of the component force of the tension force introduced by the PC tension material is rectangular. There is a problem that the prestress is not uniformly distributed, unlike the longitudinal direction and the lateral direction.

    Therefore, in view of the above-described problems of the prior art, the present invention can be used as a runway base or a pier base by placing it on a lower support structure such as a pile supported on the bottom of the water at sea. The purpose of the present invention is to provide a rectangular prestressed concrete slab for prestressed concrete floor plates that is small in size, can withstand extremely large loads compared to conventional products, and can be manufactured at low cost.

The feature of the invention described in claim 1 for solving the conventional problems as described above and achieving the intended object is that a rectangular precast concrete plate main body is slanted between both long sides of the rectangular shape. One linear high-rigidity part arranged toward the other side and the other linear high-rigidity part arranged obliquely opposite to this, and the central portions of the linear high-rigidity parts intersect each other A plurality of X-type high-rigidity portions arranged in an X-shape are provided in an arrangement in which a plurality of X-shaped high-rigidity portions are arranged in the longitudinal direction of the rectangular shape, and a PC tension material is applied to each linear-type high-rigidity portion constituting each X-type high-rigidity portion. In precast concrete slabs for prestressed concrete floor plates that are inserted and applied with prestress toward the linear high-rigidity portions of the X-type high-rigidity portions, the X-type high-rigidity portions arranged side by side are adjacent to each other. Fits linear type high rigidity The PC tension material insertion hole is provided continuously through the continuous portion, and is connected to the linear high-rigidity portions adjacent to each other. The PC tension material insertion hole is continuously provided in the PC tension material insertion hole. By inserting and tensioning, pre-stress is introduced in succession to one linear high-rigidity part and the other linear high-rigidity part of the X-type high-rigidity parts adjacent to each other .

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the linear high-rigidity portion protrudes from the bottom surface of the precast concrete plate main body, and the height of the straight-type high-rigidity portion is highest at the center portion and gradually reaches both ends. This is because it is provided with a straight ridge that is lowered .

A feature of the invention described in claim 3 is that, in addition to the configuration of any one of claims 1 and 2, a peripheral high-rigidity portion is integrally provided on the four peripheral sides of the precast concrete plate main body. .

According to a fourth aspect of the present invention, in addition to the configuration of the third aspect, the peripheral high-rigidity portion is integrally provided with a circumferential ridge protruding from the bottom surface along the four sides of the precast concrete plate body. This is because of the configuration .

    The precast concrete slab for prestressed concrete floorboard according to the present invention is a rectangular precast concrete slab body, one linear high-rigidity portion disposed obliquely between both long sides of the rectangular shape, and An X-type high-rigidity portion, which is composed of the other straight-type high-rigidity portion arranged in the opposite diagonal direction and arranged in an X shape by crossing the center portions of the respective linear-type high-rigidity portions, Each of the X-type high-rigidity portions of the X-type high-rigidity portion is inserted into each linear-type high-rigidity portion of the X-type high-rigidity portion. As a result of applying prestress toward the surface, a tension force is applied substantially evenly in the longitudinal direction and the short direction of the rectangle, and the bending mode generated by supporting the four sides of this PCaC plate to form the floor board. This corresponds to the characteristic that the distribution of the bending point, that is, the bending moment, is the largest in the central portion and decreases as it reaches the peripheral portion. Compared with the one in which the prestress is introduced in the direction between the sides, the overall weight is small, and the tension for the prestress to be introduced is small. Furthermore, compared with the case where the PCaC plate is formed in a square shape, the number of sheets constituting the floor board is reduced, the working efficiency is improved, and the construction cost can be reduced.

Further, in the present invention, the end portions of the linear high-rigidity portions adjacent to each other of the X-type high-rigidity portions arranged side by side are integrally continuous, and the linear high-rigidity portions that are adjacent to each other through the continuous portion. A PC tension material insertion hole that is continuous with the PC tension material insertion hole, and a PC tension material insertion hole that is continuously inserted into the PC tension material to be tensioned. By introducing the prestress continuously with the other linear high-rigidity part, it is possible to introduce the prestress so that the central part has a sufficient load resistance against the super-large load.

Furthermore, the linear high-rigidity part is configured by integrally including a linear protrusion that protrudes from the bottom surface of the precast concrete plate body and whose height is the highest at the center and gradually decreases toward both ends. A PCaC plate having a large load resistance difference between the central portion and the peripheral portion can be easily manufactured.

Furthermore , since the peripheral high-rigidity part is integrally provided on the four sides of the precast concrete plate body, even if a large local load acts on a part of the surface of the PCaC plate, the warp of the plate itself is warped. It becomes difficult to generate | occur | produce, and the stable super-heavy load floor board structure can be comprised.

Further, the peripheral high-rigidity part is configured by integrally including circumferential ridges that protrude from the bottom surface along the four sides of the precast concrete plate body, thereby facilitating its manufacture.

    Next, the precast concrete slab for prestressed concrete floorboard according to the present invention will be described based on examples.

    1 to 5 show an example of a precast concrete plate for prestressed concrete floor board (hereinafter referred to as a PCaC plate), and reference numeral 1 in the drawing denotes a PCaC plate body.

The PCaC plate main body 1 has a rectangular shape in which four corners are cut out in a chamfered shape, and necessary reinforcement is provided inside although not shown.

    In this PCaC plate main body 1, a linear high-rigidity portion 3 arranged obliquely between both long sides 2, 2 of a rectangular shape, and an arrangement opposite to this linear high-rigidity portion 3 are arranged obliquely. X-type high-rigidity portions 5 and 5, each of which is composed of a straight-type high-rigidity portion 4 and arranged in an X shape by crossing the central portions of the respective linear-type high-rigidity portions 3 and 4, are arranged in the longitudinal direction of the rectangle. They are arranged side by side.

    Further, each X-type high-rigidity portion 5, 5 is located between the X-type high-rigidity portions 5, 5 adjacent to each other, at the end of the straight-type high-rigidity portion 3 of one X-type high-rigidity portion 5, and the other X-type high-rigidity portion 5, 5. The end of the linear high-rigidity part 4 of the mold high-rigidity part 5 is arranged to intersect.

    The straight type high-rigidity parts 3 and 4 are arranged on the bottom surface of the PCaC plate main body 1 so as to be inclined obliquely from the corner of one long side to the other long side 2 opposite to the corner. , 4a are integrally formed, the bottom surface of the PCaC plate body 1 is locally built up, and the rigidity of the portion is increased.

    The linear protrusions 3a and 4a are formed so that their substantially central portions intersect each other, and the height at the intersecting portion, that is, the central portion of the X-type high-rigidity portion 5 is the highest and decreases toward both ends.

    In addition, each of the straight ridges 3a and 4a is disposed between the X-type high rigidity portions 5 and 5 adjacent to each other, at the end of the straight ridge 3a of one X-type high rigidity portion 5 and on the other X-type high rigidity portion 5a. The ends of the straight linear ridges 4a of the rigid portion 5 are crossed with each other at the central portion in the longitudinal direction of the rectangle, and both X-type high-rigid portions 5, 5 are formed in a symmetrical arrangement via the rectangular center. Yes.

    Peripheral high-rigidity portions 6 are provided on the four sides around the PCaC plate main body 1. The peripheral high-rigidity portion 6 is constituted by circumferential ridges 6 a, 6 a... Integrally projectingly provided on the respective peripheral bottom surfaces of the PCaC plate main body 1, and the peripheral portion of the PCaC plate main body 1 is overlaid. As a result, the rigidity of the cross section is locally increased.

    Each of the circumferential ridges 6a, 6a... Is integrated with the end portions of the linear ridges 3a, 4a described above, and is formed in a continuous arrangement in the circumferential direction.

    The straight high rigidity portions 3 and 4 constituting the X high rigidity portions 5 and 5 are each formed with a PC tension material insertion hole along the longitudinal direction thereof. This PC tension material insertion hole is formed by, for example, embedding a steel pipe sheath such as a spiral wound pipe at the time of concrete placement molding of the PCaC plate main body 1 and / or the respective protrusions 3a, 4a, 6a.

    One of the PC tendon insertion holes is open at the corner and the other is at the long side facing the corner, and the PC tendon insertion hole passing through the linear rigid portion 3 is the other at the center. It arrange | positions so that it may cross | intersect the PC tendon material insertion hole which passes through the inside of the linear type high-rigidity part 4 of this.

    Further, between the X-type high-rigidity portions 5 and 5 adjacent to each other, the PC tension material insertion hole passing through the linear high-rigidity portion 3 of one X-type high-rigidity portion 5 and the other X-type high-rigidity portion 5 The PC tendon material insertion hole passing through the linear high-rigidity portion 4 is arranged to intersect. The PC tendon 7 is fixed to a rectangular corner at one end and to the long side 2 opposite to the corner at the other end.

    In this way, a plurality of X-type high-rigidity parts 5, 5 are arranged in the rectangular PCaC plate body 1 in the longitudinal direction of the rectangular shape and are integrally provided, and each of the X-type high-rigidity parts 5, 5 constitutes a linear high-rigidity part. The PC tension material 7 is inserted into 3 and 4, and prestress is applied by applying equal tension between each corner (long side) and the long side.

    Thereby, the introduced prestressed force is large at the central portion of the X-type high-rigidity portion 5, that is, at the intersection of the linear high-rigidity portions 3 and 4, even in the rectangular longitudinal direction and short-side direction. In the middle part of the rectangle, the linear high-rigidity part 3 of one X-type high-rigidity part 5 and the other X-type high-rigidity part 5 have a small stress distribution as they go. Since the linear high-rigidity portion 4 of the die high-rigidity portion 5 is crossed, a sufficient load resistance can be obtained.

    In order to manufacture such a PCaC plate, for example, as shown in FIG. 6, an X comprising linear protrusions 3a and 4a arranged in an X shape so as to cross each other and a PCaC plate main body portion on the upper side. X-type high-rigidity part constituting member constituting the mold-type high-rigidity part 5, and peripheral-part high-rigidity part constituting member constituting the peripheral-part high-rigidity part 6 composed of the circumferential ridge 6a and the PCaC plate body portion on the upper side thereof The high-rigidity component member 10 in which is integrated is molded. That is, the X-type high-rigidity constituent members constituting the X-type high-rigidity parts 5 and 5 are arranged side by side, and the peripheral high-rigidity part constituting members of the peripheral high-rigidity part 6 are arranged around it. The high-rigidity component member 10 having the spaces a, a ... penetrating in the up-down direction is molded.

    Next, the PC tension member 7 is inserted into the X-type high-rigidity component of the high-rigidity component 10 in the direction of the linear high-rigidity. The insertion of the PC tendon 7 may be performed by embedding an unbonded PC tendon in advance, or a high-rigidity component member is concretely cast by embedding a sheath for inserting the PC tendon in advance. Further, a PC tension material such as a PC steel rod or PC strand may be inserted into the sheath.

    In this way, the PC tendon 7 is inserted, and as shown in FIG. 7, one end thereof is fixed to one end of the linear high-rigidity portion of the X-type high-rigidity constituent member, and the other end is pulled by the hydraulic jack 11. The prestress is introduced by fixing to the other end of the linear high-rigidity component member in a tension state. In the figure, reference numeral 12 denotes a pressure bearing plate fixed to the opening end of the PC tension member insertion hole. The fixing tool 13 is screwed with a nut on the outer periphery of the PC iron bar and supported by the pressure bearing plate 12. Various fixing methods such as a nut fixing method and a wedge fixing method in which a PC tension material is held by a wedge having a half-tapered tapered cylinder can be used.

    After prestressing is introduced into the pre-formed high-rigidity component member 10 in this way, the portion a surrounded by the X-type high-rigidity component member and the peripheral high-rigidity component member is integrally formed therewith. Concrete that constitutes the remaining flat plate portion of the PCaC plate main body 1 is placed in the substantially upper half portion to form a rectangular PCaC plate in which post-cast concrete and high-rigidity constituent members are integrated.

    The concrete may be formed by placing a portion of the concrete that constitutes the upper surface of the PCaC plate main body in an arrangement superimposed on the inside of the portion a surrounded by the high-rigidity constituent members. In addition, both the post-cast concrete and the high-rigidity constituent member are provided with necessary reinforcement inside, and in order to integrate both, desired reinforcement is provided between them.

    Thus, by pre-molding the high-rigidity component member and introducing prestress, the tension force in the direction of the straight-line high-rigidity part of the X-type high-rigidity part 5 is strongly and suitably introduced, and is sufficient in the central part. Thus, even when the necessary tension force of the PC tension material is small, a desired prestress is effectively introduced.

    In this embodiment, when pre-stress is introduced to the high-rigidity component member, the high-rigidity component material is moved in the vertical direction due to an error in tension on the PC tendon material or an error in strength of the high-rigidity component material. Twisting may occur. In this case, prior to the placement of the post-cast concrete, a reaction force receiver is installed on the high-rigidity component member, and supported by this with a pressurizer such as a hydraulic jack, the upper surfaces of the four rigid-component components. Further, the upper surface of the long side portion is pressed downward to correct the flatness to a predetermined level.

    In this state, post-cast concrete is placed on the remaining portion of the flat portion of the PCaC plate main body and integrated with the high-rigidity component. The concrete is solidified and a predetermined strength is exhibited, so that the torsion of the high-rigidity component is maintained in a corrected state, and the flatness of the PC plate is maintained even after the correction force is released by the pressurizer. The

    Note that the flatness of the high-rigidity component using a pressurizer is forced even if distortion such as torsion does not occur or does not occur depending on the size of the PC plate to be manufactured and the prestress to be introduced. It is not always necessary when the degree is small.

    For example, when building a PC floor plate that supports super heavy loads such as runways and wharves at sea using this PCaC version A, as shown in FIGS. The beam 15 is supported on the lower support structures 14, 14... And the floor board support 16 is fixed thereon.

    This floor board support part 16 arrange | positions the crosspiece which consists of H type steel materials, a cast-in-place, or a PCaC material in a grid | lattice form, and each of the 4 sides 17,17 ... of each lattice is each 4 sides of one PCaC plate A. The PCaC plate is placed on each lattice to form a floor board extending in the plane direction.

    If each PCaC plate A to be used has all of the prestresses planned, surface pavement 18 is applied on them to form a road surface on which the vehicle or aircraft can travel. To do.

    In the above-described embodiment, the PC tendon insertion hole is formed in each high-rigidity portion along the longitudinal direction thereof, and the long side facing the corner or one long side from the corner or the long side. As shown in FIG. 10, the end portions of the linear high-rigidity portions 3 and 4 adjacent to each other of the X-type high-rigidity portions arranged side by side are integrally connected as shown in FIG. The PC tension material insertion hole is continuously provided in the linear high rigidity portions 3 and 4 which are adjacent to each other through the continuous portion, and the PC tension material 7 is inserted continuously through the PC tension material insertion hole. By tensing, the X-type high-rigidity part 5 of one X-type high-rigidity part 5 and the linear-type high-rigidity part 4 of the other X-type high-rigidity part 5 are connected to each other. You may make it introduce tension. In addition, the same code | symbol is attached | subjected to the part same as the above-mentioned Example, and description is abbreviate | omitted.

Thereby, the introduced prestressed force is large at the central portion of the X-type high-rigidity portion, that is, at the intersection of the linear high-rigidity portion, and is small as it goes to the peripheral portion in the rectangular longitudinal direction and short-side direction. In the central part of the rectangle having a stress distribution, a compressive force is suitably generated in the longitudinal direction and the short direction, prestress is introduced, and a sufficient load resistance can be obtained.

    In the above-described embodiment, the PCaC plate is described as having two X-type high-rigidity portions arranged side by side. For example, as shown in FIG. 11, three PCaC plates are arranged in the longitudinal direction of the rectangular PCaC plate body 1. The above X-type high-rigidity parts may be arranged side by side. In addition, the same code | symbol is attached | subjected to the part same as the above-mentioned Example, and description is abbreviate | omitted.

    In the above-described embodiment, the case where the peripheral high-rigidity portion is integrally provided around the PCaC plate main body 1 has been described, but the peripheral high-rigidity portion may not be provided.

    In the above-described embodiment, a case where a so-called post-tensioning method in which a PC tension material insertion hole is formed in each high-rigidity portion and a pre-stress is introduced through the PC tension material is shown. The PC tension material is placed in the formwork in a tensioned state, and concrete is placed there to form the above-mentioned PCaC plate. After the concrete has solidified, both ends of the PC tension material are cut to form a PCaC plate. A precast concrete plate for a prestressed concrete floor board may be formed by a so-called pretensioning method in which prestress is introduced.

It is a front view which shows an example of implementation of the precast concrete plate for prestressed concrete floor boards which concerns on this invention. It is a bottom view which shows a PCaC plate same as the above. FIG. 3 is a view taken along line DD in FIG. 2. It is the EE arrow directional view in FIG. FIG. 5 is a view taken along line FF in FIG. 2. (A) is a bottom view which shows a highly rigid part structural member, (b) is the GG arrow directional view. It is sectional drawing which abbreviate | omitted one part which shows the state of the prestress introduction | transduction operation | work with respect to the highly rigid structural member shown in FIG. It is sectional drawing which shows the use condition of the precast concrete plate for prestressed concrete floor boards shown in FIG. It is a top view which notches and shows a part same as the above. It is a bottom view which shows the other Example of the precast concrete board for prestressed concrete floor boards which concerns on this invention. It is a bottom view which shows the further another Example of the precast concrete plate for prestressed concrete floor boards which concerns on this invention.

Explanation of symbols

A, B Precast concrete slab for prestressed concrete floor board 1 PCaC slab body 2 Long side 3 Straight high-rigidity part 3a Straight ridge 4 Straight high-rigidity part 4a Straight ridge 5 X-type high-rigidity part 6 Peripheral high-rigidity part 6a Circumferential ridge 7 PC tension member 10 High rigidity member 11 Hydraulic jack 12 Supporting plate 13 Fixing tool 14 Lower support structure 15 Beam 16 Floor plate support 17 Side 18 of each lattice Surface pavement

Claims (4)

In the rectangular precast concrete plate body, one straight-type high-rigidity portion arranged diagonally between the two long sides of the rectangular shape, and the other straight-type high height portion arranged diagonally opposite to this A plurality of X-type high-rigidity portions arranged in an X shape by intersecting the central portions of the respective linear-type high-rigidity portions with each other in the longitudinal direction of the rectangular shape, A prestressed concrete floor board in which a PC tension material is inserted into each linear high-rigidity portion constituting each X-type high-rigidity portion and prestress is applied in the direction of each linear high-rigidity portion of the X-type high-rigidity portion. In precast concrete plate for
The ends of the linear high-rigidity parts adjacent to each other of the X-type high-rigidity parts arranged side by side are integrally connected, and the PC tension is continued through the continuous part to the linear high-rigidity parts adjacent to each other. One straight type high rigidity part and the other straight type high rigidity part of the X type high rigidity part adjacent to each other by providing a material insertion hole and inserting and tensioning the PC tension material continuously through the PC tension material insertion hole A precast concrete slab for prestressed concrete floor boards, characterized in that prestress is introduced continuously in the section . The linear high-rigidity area protrudes from the bottom surface of the precast concrete panel body, according to claim 1 which is constructed by integrally provided with a linear ridge gradually lowered as reaching its height highest across the central portion A precast concrete plate for prestressed concrete floorboard as described in 1. The precast concrete plate for prestressed concrete floor boards according to any one of claims 1 and 2 , wherein peripheral high-rigidity portions are integrally provided on four sides of the precast concrete plate body. The precast concrete slab for prestressed concrete floor boards according to claim 3, wherein the peripheral high-rigidity portion is integrally provided with circumferential ridges protruding from the bottom surface along the four sides of the precast concrete slab body.

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