JP2008144459A - Slab form and method of constructing composite floor slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of constructing a composite floor slab by using a slab form which is a permanent form doubling as timbering, excellent in water resistance and corrosion resistance, contributes to labor saving during construction, and achieves elongation of the span of the floor slab without largely increasing the weight of the floor slab. <P>SOLUTION: According to the method of constructing the composite floor slab 120, firstly WT slab forms 10 are integrally molded of high-strength fiber-reinforced mortar, and each have a WT-shaped cross section. A band-shaped bottom board 11 of each slab form has a sufficient reinforcement covering depth, and band-shaped webs 12 arranged in two rows each have a number of through holes 12a formed therein in a direction intersecting the band-shaped web 12. Further, prestress is introduced to the slab form in a direction along the band-shaped webs 12. The WT slab forms 10 thus formed are arranged in parallel with each other in the span with the band-shaped webs 12 facing upward. Then, reinforcements 121 are inserted into the through holes 12a, and reinforcements 122 are also arranged between the band-shaped webs 12, followed by pouring concrete 20 on the WT slab forms 10, to thereby construct the composite floor slab 120 of a pier, which is a unitary body of the WT slab forms 10 and the concrete 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a slab formwork such as a concrete bridge and a method for constructing a composite slab using the slab formwork.

  Conventionally, a cast-in-place slab of RC structure formed by cast-in concrete is known. The cast-in-place slab is a floor slab constructed by assembling a support and a formwork between the supports, placing reinforcing bars in the formwork, and placing concrete.

  However, the maximum span length in the cast-in-place slab of RC structure is generally about 5 m to 7 m, and it is difficult to further increase the span length. Moreover, since it is necessary to assemble a support work and a formwork, it is difficult to save labor of construction. In addition, when the formwork is removed after the floor slab is constructed, it is necessary to work on the bottom surface of the floor plate. However, when this cast-in-place slab of RC structure is applied to a harbor structure such as a pier, Since the space is narrow and waves are applied, it is difficult to remove the formwork on the lower surface of the floor board.

  Conventionally, a synthetic floor slab using a mold made of FRP (fiber reinforced plastic) is also known (see, for example, Non-Patent Document 1). This FRP formwork composite floor slab uses FRP material with reinforcing ribs formed at intervals of 20 to 30 cm to ensure rigidity in the direction along the floor slab support during concrete placement as a permanent formwork for both support and support. It was a composite floor slab. Since the FRP material is excellent in water resistance and corrosion resistance, when the FRP formwork composite slab is applied to a port structure such as a pier, the durability against salt damage is high. In addition, since the FRP material is a permanent mold that is also used as a supporter, it is not necessary to assemble or remove the mold on the bottom surface of the floor slab, and labor saving can be achieved.

  However, it is difficult for the FRP material in the FRP formwork composite floor slab to have a long span between the floor slabs, similarly to the cast-in-place floor slab having the RC structure described above.

  Conventionally, a synthetic floor slab using a PC (prestressed concrete) slab is also known. This composite floor slab is replaced with a support or a formwork on the underside of the floor slab, and PC plates of factory products are arranged between the supports. Reinforcing bars are placed in the direction perpendicular to the prestress introduction at the top of the PC slab, and concrete is placed. This is a composite floor slab that is constructed by integrating the PC plate and cast-in-place concrete.

  A synthetic floor slab using such a PC slab does not require a support work, and does not require assembly and removal of a formwork on the lower surface of the floor slab, so that labor saving can be achieved.

  Although this composite floor slab uses a PC plate with prestressed, it is possible to extend the span of the floor slab. However, when the floor slab span is lengthened, the PC plate's own weight or cast-in concrete In order to support its own weight and work load, it is necessary to increase the thickness of the PC plate. As a result, the thickness of the composite floor slab increases and the overall weight increases, which may make earthquake-resistant design difficult.

  In addition, in order to make the composite floor slab using the PC plate have a structure in which the PC plate and the cast-in-place floor slab are integrated with each other, in general, irregularities are formed on the surface to enhance adhesion to concrete. For example, in a two-way slab in which the four sides of a floor slab are supported, it is difficult to reliably integrate in both directions. .

  Here, the prestress introduction direction of the PC plate has a large load resistance as a PC member with respect to the load from above where tensile stress is generated on the lower surface of the composite floor plate using the PC plate. However, in the direction perpendicular to the prestress introduction of the PC plate against the load, the reinforcing bars arranged on the top of the PC plate resist, so the effective height as the RC structure is reduced and Can't resist.

Therefore, it is difficult to apply a composite floor slab using a PC plate to a two-way slab in which the four sides of the floor slab are supported and the length of each floor slab span is the same.
Steel-concrete composite structure subcommittee, "Structural engineering series 9-A Theory and design of steel-concrete composite structure (1) Fundamentals: Theory", 1st edition, Japan Society of Civil Engineers, April 1999 30th, p141-142

  In view of the above circumstances, the present invention is excellent in water resistance and corrosion resistance, can save labor for construction, and can form a long slab without greatly increasing the weight of the floor slab, And it aims at providing the construction method of the composite floor slab using such a slab formwork.

  The slab form of the present invention that achieves the above object is formed integrally with a high-strength fiber reinforced mortar, and has a shape composed of a strip-shaped bottom plate and a strip-shaped web erected on one side thereof, and the strip-shaped bottom plate has a reinforcing bar cover thickness. The belt-like web has a plurality of through holes in a direction intersecting with the belt-like web, and prestress is introduced in a direction along the belt-like web.

  Here, the high-strength fiber reinforced mortar of the present invention is, for example, a short fiber reinforcing material such as steel fiber, PVA (Polyvinyl Alcohol) fiber, PE (Polyethylene) fiber, etc., in a cement having a water cement ratio of about 30% or less. Cement-based ultra-high strength material mixed with fine aggregate. This high-strength fiber reinforced mortar has a compressive strength of about 100 MPa to about 180 MPa, a bending strength of about 15 MPa to about 25 MPa, a tensile strength of about 8 MPa, a conventional compressive strength of about 40 MPa to about 60 MPa, and a bending strength of 6 It is a material with high strength and high toughness as compared with ordinary concrete having a tensile strength of about 3.5 MPa. Moreover, since this high-strength fiber reinforced mortar is a material that does not use coarse aggregate, it has good fluidity and excellent workability.

  Since the slab form of the present invention is integrally molded with a high-strength fiber reinforced mortar having a lower water-cement ratio than ordinary concrete, the neutralization rate and the salt permeability are very low. Therefore, when the slab form of the present invention is applied to a harbor structure such as a pier, durability against salt damage deterioration is improved.

  Moreover, since the slab formwork of this invention is comprised from the strip | belt-shaped baseplate and the strip | belt-shaped web, it is excellent in portability. Moreover, since the slab formwork of the present invention can be used as a permanent formwork that also serves as a supporter, it is possible to save labor in construction.

  Moreover, since the strip | belt-shaped web of this invention is provided with many through-holes of the direction where a strip | belt-shaped web cross | intersects this strip | belt-shaped web, a reinforcing bar can be inserted in the through-hole.

  Furthermore, the slab formwork of the present invention is integrally molded with a high-strength fiber reinforced mortar that is a high-strength and high-toughness material, and prestress is introduced in the direction along the belt-like web. Even when the span is made longer, it is possible to increase the height of the belt-like web without increasing the thickness of the belt-like bottom plate. Therefore, by using the slab form of the present invention, it is possible to increase the span span of the floor slab without greatly increasing the weight of the floor slab.

  In addition, the strip | belt-shaped web in the slab formwork of this invention says the continuous or intermittent one or more row | line | column standingly arranged on the single side | surface of the said strip | belt-shaped baseplate.

  Further, the method for constructing the composite floor slab of the present invention that achieves the above object comprises arranging the slab form of the present invention side by side with the strip-shaped webs facing upward, inserting reinforcing bars into the numerous through holes, It is characterized by placing concrete on a formwork to form an integrated floor slab.

  Since the method for constructing the composite floor slab of the present invention uses the slab formwork of the present invention, it has excellent water resistance and corrosion resistance as well as the above-mentioned advantages of the slab formwork of the present invention, and labor saving of construction. It is possible to increase the span length of the floor slab without greatly increasing the weight of the floor slab.

  Here, in the above-mentioned integrated floor slab, the direction of crossing with the strip-shaped web of the slab form is that the concrete placed on the slab form is filled into the through-holes through which the rebar is inserted, so that the rebar and concrete shear It is surely integrated by the transmission force. Moreover, the direction along the strip | belt-shaped web of a slab formwork in the integrated floor slab is reliably integrated with the strip | belt-shaped web of a slab formwork. Therefore, the composite floor slab construction method of the present invention can also be applied to, for example, a two-way slab in which the four sides of the floor slab are supported and the length of each floor slab span is the same.

  In the method for constructing the composite floor slab of the present invention, the slab form of the present invention may be arranged side by side with the strip-shaped web on the upper side, and then rebars may be inserted through the numerous through holes. The slab molds of the present invention may be installed together on the ground using, for example, a crane, after the strip-shaped webs are arranged side by side on the ground and the reinforcing bars are inserted through the many through holes on the ground.

  According to the slab formwork of the present invention, it is excellent in water resistance and corrosion resistance, can save labor in construction, and can extend the span of the floor slab without greatly increasing the weight of the floor slab.

  Further, according to the method for constructing a composite slab of the present invention, it is excellent in water resistance and corrosion resistance, can save labor in construction, and can extend the span of the slab without greatly increasing the weight of the slab. Is possible. Further, for example, the present invention can also be applied to a two-way slab in which the four sides of the floor slab are supported and the length of each floor slab span is approximately the same.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a front view showing a WT slab form 10 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA in FIG.

  A WT slab form 10 shown in FIGS. 1 and 2 is integrally formed with a high-strength fiber reinforced mortar, and has a shape composed of a belt-like bottom plate 11 and two rows of belt-like webs 12 erected on one side thereof. .

  This high-strength fiber reinforced mortar is a cement system in which steel fibers, which are short fiber reinforcements, are mixed with silica fume cement (registered trademark) having a water cement ratio of about 20% or less together with fine aggregates having a particle size of about 5 mm or less. Ultra high strength material. This high-strength fiber reinforced mortar has, for example, a compressive strength of about 150 MPa, a bending strength of about 20 MPa, a tensile strength of about 8 MPa, a conventional compressive strength of about 40 MPa to about 60 MPa, a bending strength of about 6.5 MPa, Compared to ordinary concrete with a tensile strength of about 3.5 MPa, it is a material with high strength and toughness. Moreover, since this high-strength fiber reinforced mortar is a material that does not use coarse aggregate, it has good fluidity and excellent workability. The high strength fiber reinforced mortar shown here is one design example of the high strength fiber reinforced mortar of the present invention, and the high strength fiber reinforced mortar of the present invention is not limited thereto.

  The WT slab form 10 shown in FIGS. 1 and 2 is a solid concrete integrally formed with a high-strength fiber reinforced mortar having a water-cement ratio lower than that of ordinary concrete. Very low penetration. Therefore, when this WT slab form 10 is applied to a port structure such as a pier, durability against salt damage deterioration is improved.

  As shown in FIGS. 1 and 2, the WT slab mold 10 has a WT shape in cross section, and the strip-shaped bottom plate 11 has a reinforcing bar cover thickness, and each of the two strips of strip-shaped webs 12 has this strip-shaped web. A large number of through-holes 12 a in the direction intersecting 12 are provided. Since the WT slab form 10 is used for the construction of a pier as will be described later, the thickness of the strip-shaped bottom plate 11 ensures a rebar cover for satisfying durability such as deterioration due to salt damage. For example, about 40 mm. As described above, the WT slab form 10 has a very low neutralization rate and a low salt permeability, and therefore can reduce the rebar cover compared to ordinary concrete. The WT slab mold 10 has, for example, a belt-like bottom plate 11 having a width of 1000 mm and a belt-like bottom plate 11 having a length of 6400 mm, and a belt-like web 12 having a height of 180 mm and a width of 100 mm having a major axis of 120 mm and a minor axis of 50 mm. A through hole 12a is formed.

  As described above, the WT slab form 10 of the present embodiment is excellent in portability because the width formed by the belt-like bottom plate 11 and the belt-like web 12 is 1000 mm. Moreover, since this WT slab formwork 10 can be used as a permanent formwork that also serves as a supporter, it is possible to save labor in construction. Further, since the WT slab mold 10 is provided with a plurality of through holes 12a in the belt-like web 12, rebars can be inserted into the through holes 12a.

  In addition, as shown in FIG. 2, in the WT slab mold 10, a PC steel material 13 is arranged in a direction along the belt-like web 12 and prestress is introduced.

  Thus, the WT slab form 10 of the present embodiment is integrally formed with a high-strength fiber reinforced mortar that is a high-strength and high-toughness material, and prestress is introduced in the direction along the belt-like web 12. Therefore, even when the space between the floor slabs is lengthened, it can be dealt with by increasing the height of the belt-like web 12 without increasing the thickness of the belt-like bottom plate 11. Therefore, by using the WT slab form 10 shown in FIGS. 1 and 2, it is possible to increase the span span of the floor slab without greatly increasing the weight of the floor slab.

  Next, a method for constructing a two-way slab pier which is one embodiment of the method for constructing a composite floor slab of the present invention and which supports the four sides of the slab and has the same span length between the slabs will be described. The description will be made assuming that the main beam of this pier has already been constructed.

  FIG. 3 is a front view of the pier 100 for explaining a pier construction method which is an embodiment of the synthetic floor slab construction method of the present invention. 4 is a cross-sectional view taken along line BB in FIG. 3, and FIG. 5 is an enlarged view of a portion C shown in FIG. FIG. 6 is a perspective view of the composite floor slab 120 in the jetty 100.

  First, as shown in FIGS. 3 and 5, a mortar 111 is placed on the upper surface of the main beam 110 on which the WT slab form 10 is to be placed. After curing the mortar 111, as shown in FIG. 3 and FIG. 4, the WT slab form 10 shown in FIG. 1 and FIG.

  Next, as shown in FIG. 6, the strip-shaped web 12 is inserted into a large number of through holes 12 a in the direction intersecting with the strip-shaped web 12 provided in the strip-shaped web 12 of the WT slab mold 10. Reinforcing bars 121 are arranged in a direction intersecting with. Further, by arranging the reinforcing bars 122 between the strip-shaped webs 12 of the WT slab mold 10, the reinforcing bars 122 in the direction along the strip-shaped web 12 are arranged. The rebar 122 is connected to the upper part of the main beam 110 by pressure welding or a joint 123.

  Next, the concrete 20 is placed on the WT slab mold 10 in which the reinforcing bars 121 and 122 in the direction intersecting with the strip web 12 and the direction along the strip web 12 are arranged, and the WT slab mold 10 and the cast-in-place 10 are cast in place. The composite floor slab 120 of the jetty 100 in which the concrete 20 is integrated is constructed.

  The composite floor slab 120 of the pier 100 constructed in this way is excellent in water resistance and corrosion resistance, and is labor-saving in construction, similarly to the advantages of the WT slab form 10 described with reference to FIGS. In addition, it is possible to extend the length of the floor slab without greatly increasing the weight of the floor slab.

  Moreover, the direction which cross | intersects the strip | belt-shaped web 12 in this synthetic | combination floor slab 120 is the reinforcing bar 121 by which the concrete 20 cast on the WT slab form 10 is filled in the through-hole 12a which penetrated the reinforcing bar 121. The concrete 20 is reliably integrated by the shear transmission force of the concrete 20. Further, the direction along the strip web 12 in the composite floor slab 120 is surely integrated by the strip web 12 of the WT slab mold 10.

  Therefore, the composite structure can be resisted against a load from the bottom that causes a compressive stress on the lower surface of the composite floor slab 120 such as a lifting pressure by a wave.

  In the above-described embodiment, the example in which the slab formwork of the present invention is applied to the pier construction method has been described. However, the slab formwork of the present invention is not limited to this, and for example, a composite floor of a bridge It can also be applied to concrete structures using plates such as plates and tank sidewalls.

  In the above-described embodiment, the slab form of the present invention has been described with reference to an example in which the slab form is a WT slab form having a shape composed of a strip-shaped bottom plate and two rows of strip-shaped webs erected on one side. The slab formwork of the present invention is not limited to this, and may be any slab formwork having a strip-like bottom plate and one or more rows of continuous or intermittent strip-like webs erected on one side thereof.

  In the above-described embodiment, the example in which the composite floor slab is a pier has been described. However, the synthetic floor slab construction method of the present invention is not limited to the pier construction method, and the slab formwork of the present invention. Any method for constructing a composite floor slab can be applied as long as the composite floor slab is constructed by arranging the two in parallel.

  Further, in the above-described embodiment, the slab formwork of the present invention has been described with an example in which reinforcing bars are inserted into the numerous through holes after the strip-shaped web is arranged in parallel with the strip-shaped web on the upper side. The method for constructing the composite floor slab is not limited to this, and after the slab formwork of the present invention is juxtaposed on the ground with the belt-shaped web on the upper side, rebars are inserted through the numerous through holes on the ground. For example, you may install in a lump between branches using a crane.

It is a front view which shows the WT slab formwork which is one Embodiment of this invention. It is a cross-sectional view along line AA in FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is the front view of this pier explaining the construction method of the pier which is one Embodiment about the construction method of the composite floor slab of this invention. FIG. 4 is a cross-sectional view taken along line BB in FIG. 3. It is an enlarged view of the C section shown in FIG. It is a perspective view of the composite floor slab in a jetty.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 WT-type slab form 11 Strip-shaped base plate 12 Strip-shaped web 12a Through-hole 13 PC steel 20 Concrete 100 Pier 110 Main beam 111 Mortar 120 Composite floor slab 121,122 Reinforcement 123 Joint

Claims (2)

  The belt-shaped bottom plate and a belt-like web erected on one side thereof are integrally formed with a high-strength fiber-reinforced mortar. The belt-like bottom plate has a reinforcing bar cover thickness, and the belt-like web intersects the belt-like web. A slab formwork comprising a number of through-holes in a direction and prestress is introduced in a direction along the belt-like web.   The slab formwork according to claim 1 is arranged side by side with the belt-shaped web facing upward, reinforcing bars are inserted into the numerous through holes, and concrete is placed on the slab formwork to form an integrated floor slab. A method for constructing a composite floor slab characterized by:

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