JP2006063513A - Precast concrete slab for prestressed concrete floor slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prestressed concrete slab which can be used as a base course of a runway and that of a wharf, the weight of which is light, which can bear a load greater than a conventional product, and which can be inexpensively manufactured. <P>SOLUTION: A diagonal-direction high-rigidity part 3, the rigidity of which is maximized in the central part of a diagonal line and made gradually lower toward both ends, is continuously arranged between both the opposite angles of a square PCaC slab body 1, and PC tendons 6a and 6a are inserted into the high-rigidity part 3, so that prestress can be imparted in both the diagonal directions. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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 slabs (hereinafter referred to as PCaC slabs) 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 (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 has been 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 PCaC plate with a large area 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, warping occurs in the plate itself, and a situation occurs where the corners are lifted, 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.

  In view of the conventional problems as described above, 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 water bottom at sea, and its weight is small. The present invention has been made for the purpose of providing a PCaC plate capable of withstanding an extremely large load as compared with conventional products and capable of forming a PC floor board that can be manufactured at low cost.

  In order to solve the conventional problems as described above and achieve the intended purpose, the feature of the invention described in claim 1 is that the rigidity of the rectangular PCaC plate main body is larger than that of the surroundings between the diagonals. A PCaC plate for prestressed concrete floor boards, in which directional high-rigidity portions are provided in a continuous arrangement and PC diagonal material insertion holes are provided in the diagonally high-rigidity portions.

  The invention according to claim 2 is characterized in that, in addition to the configuration of claim 1, the diagonally high-rigidity portion is integrally formed with diagonal ridges continuously raised in the diagonal direction on the bottom surface of the PCaC plate main body. It is in having constituted by preparing for.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the diagonally high-rigidity portion has a rigidity that is largest at the central portion of the diagonal line and gradually decreases toward both ends. is there.

  According to a fourth aspect of the present invention, in addition to the configuration of the third aspect, the diagonally high-rigidity portion is continuously raised in the diagonal direction on the bottom surface of the PCaC plate main body, and the height of the central portion is increased. That is, it is configured by integrally providing diagonal ridges that are highest and gradually lowered toward both ends.

  The feature of the invention described in claim 5 is that, in addition to the configuration of claims 1 to 3 or 4, a peripheral high-rigidity portion having increased rigidity on the four sides around the PCaC plate body is provided. It is in.

  According to a sixth aspect of the present invention, in addition to the structure of the fifth aspect, the peripheral high-rigidity portion is integrally provided with a circumferential protrusion having a bottom surface raised along the four sides of the PCaC plate body. It is to be constituted by.

  The invention according to claim 7 is characterized in that, in addition to the configuration of claims 1 to 5 or 6 described above, by inserting and tensioning the PC tendon through the PC tendon insertion hole, This is because prestress was introduced.

  The feature of the invention described in claim 8 is that the rigidity is larger than the surroundings between the diagonals of the rectangular precast concrete plate body, and the rigidity is largest at the central part of the diagonal and gradually decreases as it reaches both ends. The prestressed concrete slab for prestressed concrete floor board is provided by arranging the diagonally high rigidity parts in a continuous arrangement, embedding a PC tendon material in the diagonally high rigidity parts, and applying prestress in the double diagonal direction. .

  According to a ninth aspect of the present invention, in addition to the configuration of the eighth aspect, the diagonally high-rigidity portion is continuously raised in the diagonal direction on the bottom surface of the precast concrete plate main body, and the height thereof is increased to the central portion. It is to be provided integrally with diagonal ridges that are the highest and gradually lowered toward both ends.

  The feature of the invention of claim 10 is that, in addition to the configuration of claim 8 or 9, a circumferential ridge having raised bottom surfaces along the four sides on the four sides around the precast concrete plate main body. The peripheral high-rigidity portion having increased rigidity by being provided integrally is provided.

  In the present invention, diagonal high rigidity portions having rigidity greater than that of the surroundings are provided between the diagonals of the rectangular PCaC plate main body, and PC tension material insertion holes are provided in the diagonal high rigidity portions. By providing the PC tension material through the PC tension material insertion hole and applying prestress in both diagonal directions, distribution of bending moment generated by supporting the four sides of the PCaC plate and constituting the floor board That is, a PCaC plate having a large load resistance at the center portion can be configured according to the characteristic that the bending moment is the largest at the center portion and becomes smaller as it reaches the peripheral portion. Compared with the one in which prestress is introduced, the overall weight is small, and the tension for prestress to be introduced may be small.

  The diagonal high rigidity portion may be provided by forming a ridge as described later, or may be formed by partially using high strength concrete.

  In addition, the diagonally high-rigidity portion is configured by integrally providing diagonal ridges continuously raised in the diagonal direction on the bottom surface of the PCaC plate main body, thereby providing a diagonal having higher rigidity than the peripheral portion thereof. The direction high rigidity portion can be easily formed.

  Furthermore, the diagonally high rigidity portion is prestressed in both diagonal directions by inserting the PC tendon through the PC tendon insertion hole by gradually decreasing the stiffness at the center of the diagonal and gradually decreasing toward both ends. When the is applied, the difference in load resistance between the central portion and the peripheral portion can be increased, and a PCaC plate adapted to a super heavy load can be obtained.

  Further, the diagonally high rigidity portion is integrally formed on the bottom surface of the PCaC plate main body in a diagonal direction, and the diagonal ridges that are gradually lowered from the height of the center portion to the highest point at the both ends are integrated. By configuring the PCaC plate, the PCaC plate with a large difference in load resistance between the central part and the peripheral part when the PC tendon is inserted into the PC tendon insertion hole and prestress is applied in both diagonal directions. Can be manufactured.

  Furthermore, even if a large load is locally applied to a part of the surface of the PCaC plate by providing peripheral high-rigidity portions with increased rigidity on the four sides around the PCaC plate main body. The warpage of the plate itself is less likely to occur, and a stable super heavy load floor board structure can be configured.

  Furthermore, the peripheral rigid and highly rigid portion is constituted by the circumferential ridges, so that the manufacture becomes easy.

  Furthermore, even if it is in the state before using it as a PC floor board by inserting pre-stress between the both ends of the diagonal high-rigidity part by inserting and tensioning a PC tendon through the PC tendon insertion hole Thus, a large load-bearing capacity can be obtained, and a relatively heavy vehicle or work implement can be run on the load-bearing capacity while it is still mounted on the support portion.

  In addition, between the diagonals of the square-shaped precast concrete plate body, there is a series of diagonally high-rigidity parts that have greater rigidity than the surroundings, and that the rigidity is the largest at the center of the diagonal and gradually reduced toward both ends. By placing the PC tension material in the diagonally high rigidity portion and applying prestress in the diagonal direction, the PC tension material is embedded in advance in a tensioned state. A precast concrete slab for prestressed concrete floor boards having a bending moment distribution similar to that described above can also be obtained by a so-called pretensioning method in which prestressing is introduced into concrete by releasing tension after solidifying the concrete.

  Next, embodiments of the present invention will be described based on examples shown in the drawings.

  1 shows an embodiment according to the present invention, and reference numeral 1 in the drawing denotes a PCaC plate body. This PCaC plate main body 1 is a square having substantially the same four sides 2, 2,..., And has four corners cut out in a chamfered shape. Although not shown in the figure, necessary reinforcement is provided inside. On the bottom surface of the PCaC plate main body 1, diagonally highly rigid portions 3 and 3 are integrally formed in a continuous arrangement along both diagonal lines.

  The diagonally high-rigidity portions 3 and 3 are formed by locally building up the back surface of the PCaC plate main body 1 to increase the rigidity of the portion. The angular ridges 3a and 3a are integrally formed. The two protrusions 3a, 3a are located at the central portion of the PCaC plate body 1 and intersect each other, and the intersecting portion, that is, the central portion of the protrusion 3a and the height at the central portion of the PCaC plate body 1 is formed. Is the highest and is formed lower as it reaches each diagonal portion. As a result, the rigidity of the portion where the protrusions 3a, 3a are integrally formed is highest in the central portion, and decreases as it reaches the peripheral portion.

  A peripheral high-rigidity portion 5 is provided on the bottom surface of the four sides around the PCaC plate main body 1. Each peripheral high-rigidity portion 5 is constituted by circumferential ridges 5a, 5a... Integrally projecting from the peripheral bottom surface of the PCaC plate main body 1, and is built up in the peripheral portion of the PCaC plate main body 1. Is applied to partially increase the rigidity of the cross section. The four ridges 5a on the four sides are formed in a continuous arrangement with the end of the diagonal ridge 3a described above.

  Further, PC tendon insertion holes 6 and 6 are formed in the diagonally high rigidity portions 3 and 3. The PC tendon insertion holes 6 and 6 are formed by embedding a steel pipe sheath such as a spiral wound pipe when the PCaC plate main body 1 and / or the diagonal ridge 3a is placed in concrete.

  In addition, an unbonded cable in which a PC tendon is inserted in a synthetic resin sheath so as to be movable in the axial direction may be similarly embedded, and the PC tendon insertion hole 6 may be configured by the synthetic resin sheath. In this case, the insertion work of the PC tendon is not required when introducing prestress described later.

  Each PC tendon insertion hole 6 is disposed at a position along the bottom surface of the diagonally high rigidity portion 3 and at a position along the surface of the PCaC plate main body 1.

  In this way, the diagonally high rigidity portions 3 and 3 are integrally provided to the square PCaC plate main body 1, and the PC tension members 6a and 6a are inserted into the PC tension material insertion holes 6 and 6 in the diagonal direction in the portion. Is inserted, and prestress is introduced by equal tension in the diagonally high rigidity portions.

  As a result, a prestressed concrete PCaC plate having a large stress distribution in the central portion and a small stress distribution toward both sides is formed in any square direction of the width direction.

  The pre-stress is introduced by inserting the PC tendon 6a into some or all of the PC tendon insertion holes 6 for each PCaC plate and fixing the tension in the PCaC plate production yard.

  When building a PC floor board that can support super heavy loads such as runways and wharves at sea using this PCaC version, as shown in Figs. 6 and 7, lower support such as piles supported on the bottom ground A beam 12 is supported on the structure 11, and a floor board support portion 13 is fixed thereon.

  This floor board support part 13 arrange | positions the crosspiece which consists of H-shaped steel materials or a cast-in-place, or a PCaC material in a grid | lattice form, and 4 sides 14,14 ... of each grid | lattice is 4 sides of one PCaC plate A. Each of the lattices is used as a support portion that supports each of them, and a PCaC plate A is placed on each lattice to form a floor board that spreads in the plane direction.

  If each PCaC plate A to be used has all of the planned prestresses introduced, surface pavement 15 is applied on them to form a road surface on which the vehicle or aircraft can travel. To do.

  In addition to the above, as shown in FIG. 7, a PCaC plate in which a part or all of the prestress is not introduced is used, and is continuously connected to PCaC plates A, A. May be inserted and prestressed at the same time for a plurality of PCaC plates. In this case, a continuous long PC tension material may be inserted across a plurality of PCaC plates A, A... At the PC floor board construction site, and as shown in FIG. PC tension members 6a are inserted and connected with a coupler 8 so that PC tension members 6a, 6a... Of PCaC plates A, A. Tension may be introduced and prestress may be simultaneously introduced to a plurality of PCaC plates.

  FIG. 9 shows another embodiment of the present invention. This embodiment has both the diagonal high rigidity portion 3 and the peripheral high rigidity portion 5 in the above-described embodiment, but does not have the peripheral high rigidity portion. Diagonal high-rigidity portions 3 and 3 are integrally formed in a continuous arrangement along both diagonal lines on the bottom surface of the PCaC plate body 1 having a square flat plate shape cut into a chamfered shape.

  The diagonally high rigidity portions 3 and 3 are configured by integrally forming diagonal ridges 3a and 3a integrally formed continuously at both diagonal positions on the back surface of the PCaC plate main body 1. The two protrusions 3a, 3a are located at the central portion of the PCaC plate body 1 and intersect each other, and the intersecting portion, that is, the central portion of the protrusion 3a and the height at the central portion of the PCaC plate body 1 is formed. Is the highest and is formed lower as it reaches each diagonal portion. Both ends of the ridges 3a and 3a are located in front of the peripheral edge of the PCaC plate body 1, and the bottom surface of the peripheral portion of the PCaC plate body 1 is used as a support surface 9.

  As shown in FIG. 10, the PC tension material insertion holes 6 and 6 are formed on the lower side through the protrusion 3 a from the peripheral edge of the PCaC plate main body 1, and the upper one is the surface of the PCaC plate main body 1. It is inserted along the side.

  The insertion of the PC tendon material by the PCaC plate, the introduction of the prestress by the tension fixation and the construction of the PC floor board are the same as in the above-described embodiment.

    In the above-described embodiment, the case where the PC tension material insertion hole is formed in the diagonal direction and the PC tension material is inserted into the PC tension material to introduce prestress is shown. In addition, although not shown in the figure, the rigidity is larger than the surroundings between the diagonals of the square-shaped precast concrete plate body, and the rigidity is largest at the central part of the diagonal and gradually decreases as it reaches both ends. The prestressed concrete according to the present invention is provided by a so-called pretensioning method in which the diagonally high rigidity portions are provided in a continuous arrangement, and a PC tension material is embedded in the diagonally high rigidity portions to apply prestress in the diagonal direction. A precast concrete plate for floor board may be constituted.

  In this case, as described above, the diagonally high-rigidity portion is continuously raised in the diagonal direction on the bottom surface of the precast concrete plate main body, and the height thereof is the highest at the central portion and gradually lowered toward the both ends. It can be configured by integrally providing angular ridges, and by integrally providing circumferential ridges with raised bottom surfaces along the four sides around the four sides of the precast concrete plate body. A peripheral high-rigidity portion having increased rigidity may be provided.

It is a front view of an example of implementation of the PCaC plate concerning the present invention. It is a bottom view same as the above. It is the EE sectional view taken on the line in FIG. It is the FF sectional view taken on the line. It is a bottom view which shows the state which gave the prestress to the PCaC plate shown in FIG. It is sectional drawing which shows the use condition of the PCaC plate | version | printing shown in FIG. It is a top view which notches and shows a part same as the above. It is a partial enlarged plan view which shows a PC tendon connected state same as the above. It is a perspective view which shows the other Example of the PCaC plate which concerns on this invention. It is the GG sectional view taken on the line in FIG.

Explanation of symbols

A Precast concrete plate (PCaC plate)
1 Precast concrete plate body (PCaC plate body)
2 sides 3 diagonal high-rigidity part 3a diagonal ridge 5 peripheral high-rigidity part 5a circumferential ridge 6 PC tension material insertion hole 6a, PC tension material 11 lower support structure 12 beam 13 floor plate support part 14 of each lattice Side 15 Surface pavement

Claims (10)

  A prestressed structure in which diagonally high rigidity parts having rigidity greater than the surroundings are continuously arranged between the diagonals of the rectangular precast concrete plate main body, and PC tension material insertion holes are provided in the diagonally high rigidity parts. Precast concrete plate for concrete floor boards.   2. The prestressed concrete floor board according to claim 1, wherein the diagonally high rigidity portion is configured by integrally including diagonal ridges continuously raised in a diagonal direction on a bottom surface of a precast concrete plate main body. Precast concrete version.   The precast concrete slab for prestressed concrete floor board according to claim 1, wherein the diagonally high rigidity portion has a rigidity that is greatest at the center of the diagonal and gradually decreases toward both ends.   The diagonally high-rigidity portion is integrally formed with a diagonal ridge that is continuously raised in a diagonal direction on the bottom surface of the precast concrete plate body, and whose height is the highest at the center and gradually decreases toward both ends. The precast concrete slab for prestressed concrete floor board according to claim 3, wherein the precast concrete slab is constituted by comprising.   The precast concrete slab for prestressed concrete floor boards according to claim 1, further comprising a peripheral high-rigidity portion having increased rigidity on the four sides around the precast concrete plate main body.   6. The precast concrete for prestressed concrete floor board according to claim 5, wherein the peripheral high-rigidity portion is integrally provided with circumferential ridges having raised bottom surfaces along the four sides of the precast concrete plate main body. Edition.   The precast for prestressed concrete floor board according to claim 1 or 5, wherein a prestress is introduced between both ends of the diagonally high-rigidity part by inserting a PC tendon through the PC tendon insertion hole and tensioning the PC tendon. Concrete version.   Continuously arranged diagonally high-rigidity parts between the diagonals of a rectangular precast concrete plate body, with rigidity greater than that of the surroundings and with the rigidity being the largest at the center of the diagonal and gradually decreasing toward both ends A precast concrete slab for prestressed concrete floor boards, which is provided with a PC tension material embedded in the diagonally high rigidity portion and prestressed in both diagonal directions.   The diagonally high-rigidity portion is integrally formed with a diagonal ridge that is continuously raised in a diagonal direction on the bottom surface of the precast concrete plate body, and whose height is the highest at the center and gradually decreases toward both ends. The precast concrete slab for prestressed concrete floor board according to claim 8, wherein the precast concrete slab is constituted by comprising.   9. A peripheral high-rigidity portion having increased rigidity by integrally providing circumferential protrusions having raised bottom surfaces along the four sides on the four sides around the precast concrete plate main body. A precast concrete slab for prestressed concrete floorboards according to 9.

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