JP2010265623A - Reinforcing structure of steel floor slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforcing structure of a steel floor slab capable of easily and securely reinforcing the steel floor slab by a relatively lightweight reinforcing member, and improving durability resisting fatigue of the steel floor slab in reinforcing the steel floor slab of trough rib type from its lower face. <P>SOLUTION: In this reinforcing structure of the steel floor slab, a fiber reinforced cement material is sprayed on a lower face and surfaces of right and left U-rib side plates 3b, 3c of a deck plate 2 by a spray method to form a block 10 having a cross section having a substantially portal shape under the deck plate 2 between U-ribs 3 and 3, and the whole upper face of an upper part horizontal part 10a and the whole outer side faces of right and left leg parts 10b, 10c of the block 10 adhere closely to the lower face and the surfaces of the right and left U-rib side plates 3b, 3c of the deck plate 2, respectively, to support the deck plate from below, reinforce corner parts of the deck plate and the U-ribs, prevent the deck plate and the U-ribs in the corner parts from being partially deformed due to wheel load, and reduce partial stress in a welded part of the deck plate and the U-ribs, thereby improving its fatigue life. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reinforcing structure that reinforces steel decks of road bridges, bridges, and other structures from the lower surface.

  In the existing steel deck slab bridge, as shown in FIG. 3, the bridge between the deck plate 2 of the steel deck 1 and a U-shaped closed cross-section vertical rib (hereinafter referred to as U-rib) 3 continuous in the bridge axis direction. Fatigue cracks K are likely to occur in the longitudinal welded joints in the axial direction and the welds between the deck plate 2 and the vertical stiffener of the main girder web. The main cause of fatigue cracks occurring in the longitudinal welded joint between the deck plate 2 and the U-rib 3 is that the deck plate 2 is locally deformed with the U-rib 3 as a node due to the wheel load. This is thought to be the stress concentration in the weld root that occurs.

  Asphalt pavement 4 is damaged due to fatigue cracks. Against this background, the road bridge specifications revised in 1996 give consideration to pavement cracks on the main girder and cross girder. Provisions were made. Furthermore, in order to improve the durability, the “Fatigue Design Guidelines for Steel Road Bridges” was presented in 2002, and it is clearly stated in the 2002 Road Bridge Specification that the effects of fatigue should be taken into account when designing steel bridges. As a result, the rules regarding the production and construction of steel slabs have been enhanced.

  However, most of the steel slabs made before these revisions are outside the scope of the structural details such as the cross beam spacing of 2.5 m or less. Some kind of reinforcement is necessary. As a measure against fatigue of steel decks, methods such as directly reinforcing steel girders so as to satisfy the application range of fatigue design by structural details such as shortening the width of cross beams can be considered, but problems due to dead load limitations, In practice, it may be difficult to deal with such cases as the cost of repairs and reinforcement is generally high.

  On the other hand, by combining the steel floor slab and the pavement part to be constructed on its upper surface as a composite floor slab structure, replacing the asphalt provided in this pavement part with a highly rigid material such as concrete, A method for increasing the rigidity of the composite slab can be considered. By using this method, the local strain (stress) generated in the welded portion of the steel deck is reduced, and the life extension due to fatigue damage is expected. Further, as shown in FIG. 4, Patent Document 1 proposes a method of further enhancing the reinforcing effect using a high-toughness fiber-reinforced cement composite material (ECC) as a part of the pavement of the composite floor slab structure. ing. In FIG. 4, ECC51 is provided between the steel deck 1 and the surface asphalt layer. 52 is a waterproof layer and 53 is a gibber.

  Patent Documents 2 and 3 propose a method of reinforcing a steel deck from the lower surface. The invention of Patent Document 2 is intended to relieve local stress in the welded portion of the steel deck of the existing bridge and the rib and improve the fatigue life. The bolt is passed horizontally through the U rib, and a lightweight mortar or the like inside the U rib. In this filler, the middle part of the bolt is embedded, a reinforcing member is provided at the outer corner of the welded part of the steel deck and U-rib, and reinforcement is provided by nuts and cam mechanisms provided at both ends of the bolt. The member is pressed and reinforced.

  The invention of Patent Document 3 is a steel floor slab in which closed cross-section vertical ribs are fixed to the lower surface of the deck plate, and a filler is placed in the closed cross-section space of each vertical rib or in the open space between the bottom surface of the deck plate and the vertical rib. It is to be filled.

  Further, in the reinforcement from the lower surface of the steel slab, the present applicant can easily and reliably reinforce the steel slab with a relatively lightweight reinforcing member, and can improve the fatigue durability of the steel slab. We have applied for a slab reinforcement structure and reinforcement method (Patent Document 4). A flat precast concrete block made of high tough fiber reinforced cement composite (ECC) or the like is placed on the lower surface of the deck plate between the U ribs and the U ribs, and the thin steel plate on the upper surface is placed on the deck via an adhesive. The block is fixedly attached to the lower surface of the plate, and the block is fixed with a stud gibber that is fused to the lower surface of the deck plate so that the block does not fall until the adhesive is cured.

JP 2005-155187 A JP 2006-214118 A JP 2007-170178 A JP 2007-77746 A

  As a method of reinforcing the steel slab from the top surface, a method of replacing the asphalt pavement with highly rigid concrete can be considered. However, if concrete is cast thinly, cracks are generated due to drying shrinkage or the like, so that it is impossible to expect the effect of improving the yield strength and rigidity against tension and bending. Recently, steel fiber reinforced concrete has been used on a trial basis, but there are problems such as failure to completely prevent cracks, difficulty in controlling crack width, and corrosion of steel fibers due to the application of antifreeze materials. It can happen. Moreover, in the technique using the high toughness fiber reinforced cement composite material (ECC) by an organic fiber, it is the construction method which solved said subject.

  However, it is known that the fatigue durability is extremely lowered when water is stagnated due to rain or the like in common with the top surface thickening method using concrete, steel fiber reinforced concrete, and ECC. Therefore, when these are used, it is required to completely waterproof the upper surface of the steel slab, but it is often difficult with a general bridge.

  On the other hand, in the case of Patent Document 2 in which the steel deck is reinforced from the lower surface, since it is a construction method that incorporates a cam structure, it takes time to manufacture each member, and it also takes a lot of work on site. There is a problem. In the case of Patent Document 3, filling inside the U rib is good, but filling outside the U rib requires a closed space for filling the outside of the U rib, which is very labor intensive. is there.

  The present invention can easily and reliably reinforce a steel floor slab with a relatively lightweight reinforcing member in reinforcement from the lower surface of the steel floor slab such as a truffle type, and can improve the fatigue durability of the steel floor slab. It aims at providing the reinforcement structure of a steel deck.

  INDUSTRIAL APPLICABILITY The present invention is applied to reinforcement from the lower surface that does not affect traffic on an existing road in a truffle type and other types of steel slabs, and includes a U-rib (U-shaped closed section vertical rib) and a U-rib. Or between other vertical ribs and vertical ribs, install a concrete block with a cross-sectional gate shape by spraying so that it adheres to the bottom surface of the deck plate and the surfaces of the left and right vertical rib side plates (see Fig. 1). ) Or, prefabricated concrete blocks with a factory-made cross-section or a substantially inverted U-shaped cross-section are placed in contact with the bottom surface of the deck plate and the left and right vertical rib side plates (see Fig. 2). The deck plate is supported from below by a block in between, reinforcing the corners of the deck plate and vertical ribs, and suppressing local deformation of the deck plate and vertical ribs at the corners due to wheel load. Than is.

  The invention according to claim 1 of the present invention is a steel floor slab reinforcing structure in which a plurality of vertical ribs are arranged at intervals on the lower surface of the deck plate, and the deck is placed under the deck plate between the vertical ribs and the vertical ribs. By spraying concrete onto the bottom surface of the plate and the left and right vertical rib side plates by the spraying method, the concrete block with a substantially gate-shaped cross section is provided so that the surface of the concrete block adheres to the bottom surface of the deck plate and the left and right vertical rib side plates. It is the reinforcement structure of the steel deck which is characterized by the above (refer FIG. 1).

  According to a second aspect of the present invention, there is provided a reinforcing structure for a steel deck according to the first aspect, wherein a perforated plate is embedded in the concrete block. (See FIG. 1).

  This is a case where a concrete block having a substantially gate-shaped cross section by a spraying method is used in the steel plate slab bottom surface thickening reinforcement method for reinforcing the steel slab from the bottom surface. At the time of spraying, in order to ensure adhesion between the deck plate and the left and right U-rib side plates and the concrete, locking metal fittings such as stud gibels are attached in advance to the lower surface of the deck plate and the surface of the U-rib side plate. In addition, in order to prevent the material from falling during and after spraying, a perforated plate such as an expanded metal is installed.

  The invention of claim 3 of the present invention is a steel floor slab reinforcement structure in which a plurality of vertical ribs are arranged at intervals on the lower surface of the deck plate, and a cross section is provided below the deck plate between the vertical ribs and the vertical ribs. The steel floor slab reinforcement structure is characterized in that a substantially portal-shaped precast concrete block is installed so that the upper surface of the block and the side surface of the block are in contact with the lower surface of the deck plate and the surfaces of the left and right vertical rib side plates, respectively. (See FIG. 2 (a)).

  The invention of claim 4 of the present invention is a steel floor slab reinforcement structure in which a plurality of vertical ribs are arranged at intervals on the lower surface of the deck plate, and a cross section is provided below the deck plate between the vertical ribs and the vertical ribs. A substantially inverted U-shaped precast concrete block is installed such that the top surface of the block top and the part of the side surface of the block are in contact with the bottom surface of the deck plate and the surfaces of the left and right vertical rib side plates, respectively. It is the reinforcement structure of the steel floor slab to perform (refer FIG.2 (b)).

  This is a case where a precast concrete block having a substantially gate-shaped cross section by a precast installation method is used in the steel plate slab lower surface thickening reinforcement method for reinforcing the steel slab from the lower surface. It is desirable that the block is in full contact with the lower surface of the deck plate and the surfaces of the left and right vertical rib side plates (see FIG. 2A), but at least the lower surface of the deck plate and the surfaces of the left and right vertical rib side plates. If they are in contact at one point (three points A, B, and C in the cross section), a sufficient reinforcing effect can be obtained (see FIG. 2B).

  According to a fifth aspect of the present invention, in the reinforcing structure according to the third or fourth aspect, the left and right leg portions of the precast concrete block are respectively fixed to the vertical rib side plate by a stopper. It is a steel slab reinforcement structure.

  There are various methods for fixing the block, such as a method using a structural adhesive, but it is preferable to fix the block to the vertical rib side plate with a stopper such as a bolt (see FIG. 2). Moreover, it is preferable to fix the lower ends of the left and right leg portions of the block with bolts or the like. At the time of construction, cement paste, mortar or resin adhesive is applied to the upper surface of the block (in the vicinity of point A in FIG. 2) to achieve adhesion (contact) with the deck plate. In addition, even if it does not adhere | attach, if it is contacting, the deformation | transformation of a deck plate will be suppressed by the restriction effect of a block, and the reinforcement effect will be acquired.

  In the present invention, the deck plate is supported from below by a concrete block having a cross-sectional substantially portal shape by a spraying method straddling between the left and right vertical ribs, or by a precast block having a substantially cross-sectional gate shape or a substantially inverted U-shaped cross section, Because the corners of the deck plate and vertical ribs are reinforced, local deformation of the deck plate and vertical ribs at the corners due to wheel load can be suppressed, and local stress at the welded part of the deck plate and U ribs is alleviated. And the fatigue life can be improved. The steel slab can be easily and reliably reinforced by the relatively lightweight reinforcing member, and the fatigue durability of the steel slab can be improved.

  Furthermore, in the case of a concrete block having a substantially gate-shaped cross section by the spraying method, it is possible to flexibly cope with the steel plate slab bottom surface thickening reinforcement method of the existing truffle type steel slab. In the case of a precast concrete block, when a flat block is tightly fixed to the lower surface of the deck plate with a stud gibber or the like, the deck plate may be damaged. The left and right leg portions of the substantially inverted U-shaped block can be fixed to the vertical rib with a bolt or the like, and the deck plate is not damaged. In either case, the corners of the deck plate and the vertical ribs can be reinforced with a substantially gate-shaped cross section or a substantially inverted U-shaped cross section with respect to the flat block, and the corner angle caused by the wheel load can be increased. A higher reinforcing effect can be obtained with respect to local deformation of the deck plate and the vertical rib in the portion.

  In addition, when it is considered difficult to secure the adhesive force of the adhesive surface of the precast block only with an adhesive or the like, a method in which a stud gibber or the like is applied to the lower surface of the deck plate and the precast block is fitted therein Can also be used.

  A sixth aspect of the present invention is the reinforcing structure according to any one of the first to fifth aspects, wherein the concrete block is made of a fiber-reinforced cementitious material. It is a steel slab reinforcement structure.

  In order to increase the rigidity of the steel deck, it is advantageous that the material used for the block has a larger Young's modulus, and in order to prevent an increase in weight, it is desirable to be as light as possible. In order to prevent the block pieces from peeling off over a long period of time, it is necessary to use a fiber-reinforced cement material. From these points, steel fiber reinforced concrete (SFRC), organic (polypropylene) fiber reinforced concrete (PPFRC), ultra high strength fiber reinforced concrete (UFC), multiple fine cracked fiber reinforced cement composite material (HPFRCC), high toughness Fiber reinforced cement composite (ECC) is preferred. Furthermore, if tensile stress that causes cracks is generated, it is desirable to use a cement-based material that has a tensile strain-hardening type material and has elongation performance and little rigidity reduction after the occurrence of cracks. Material (ECC) is preferred.

  The concrete block is not limited to such a fiber-reinforced cement material, and polymer concrete can also be used.

  According to a seventh aspect of the present invention, in the reinforcing structure according to any one of the first to sixth aspects, the longitudinal rib is a longitudinal rib having a U-shaped trough cross section, and the entire interior or the upper portion in the interior It is a reinforcing structure of a steel slab characterized by being filled with fillers on both sides (see FIGS. 1 and 2).

  It is a case of trough rib type steel slab, and it is known that filling the inside of the U rib has the effect of reducing the stress, and the block installation outside the U rib and the filling material inside the rib (high fluid concrete or mortar) If the filling is used in combination, the reinforcing effect is further enhanced. When it is necessary to reduce the weight of the reinforcing portion, lightweight concrete or lightweight mortar can be used. Furthermore, a weight can be reduced by inserting a pipe or a balloon in the center of the lower part inside the U-rib to secure a hollow part and filling the filler into the upper part and both side parts inside the U-rib (see FIG. 2).

  Since the present invention is configured as described above, the following effects can be obtained.

(1) In the reinforcement from the bottom surface of steel floor slabs such as trough rib type, a concrete block with a cross-sectional gate shape or a cross-sectional gate shape or a substantially inverted U-shape cross-section by spraying method straddling between the left and right vertical ribs The deck plate supports the deck plate from below and reinforces the corners of the deck plate and vertical ribs, so that local deformation of the deck plate and vertical ribs at the corners due to wheel load can be suppressed, and it is relatively lightweight. The steel slab can be easily and reliably reinforced by the reinforcing member, and the fatigue durability of the steel slab can be improved.

(2) In the case of a concrete block with a substantially gate-shaped cross section by the spraying method, it is possible to flexibly cope with the steel plate slab bottom surface thickening reinforcement method of the existing truffle type steel slab.

(3) In the case of a precast concrete block, the left and right sides of the block having a substantially gate-shaped section or a substantially inverted U-shaped section can be fixed to the vertical ribs with bolts or the like, and the steel deck is not damaged.

(4) The corner plate of the deck plate and vertical rib can be reinforced with a concrete block with a cross-sectional gate shape by spraying method, or a precast block with a cross-sectional gate shape or a reverse U-shaped cross-section. With respect to the local deformation of the deck plate and the vertical rib at the corner portion due to the above, a higher reinforcing effect than the flat block can be obtained.

(5) By using a fiber-reinforced cement material for the block, the block can be further reduced in weight and rigidity.

(6) Filling the inside of the vertical rib with cement-based material, combined with the reinforcement of the block outside the vertical rib, further enhances the reinforcement effect, and inserts a pipe or balloon into the lower center of the U-rib inside the hollow part The weight can be reduced by filling the upper and both sides of the U-rib with the filler.

It is a partial vertical sectional view which shows the example of the reinforcement structure by the spraying construction method of this invention. It is a partial vertical sectional view which shows the example of the reinforcement structure by the precast installation construction method of this invention. It is the vertical sectional view and perspective view which show the mechanism of the fatigue damage of a steel deck. It is a vertical sectional view which shows the example which used ECC for a part of conventional pavement.

  Hereinafter, the present invention will be described based on the illustrated embodiments. This embodiment is an example applied to a steel floor slab bottom surface thickening reinforcement method in which a trough rib type steel slab is reinforced from the bottom surface. FIG. 1 is a partial vertical sectional view showing an example of a reinforcing structure by a spraying method according to the present invention.

  In FIG. 1, a steel plate slab 1 has a large number of U ribs (U-shaped closed cross-section vertical ribs) 3 continuous in the bridge axis direction on the lower surface of a deck plate 2 and arranged in parallel at predetermined intervals in the direction perpendicular to the bridge axis. Fixed by welding. In the embodiment of FIG. 1, the concrete is sprayed by spraying the bottom surface of the deck plate 2 and the surfaces of the left and right U-rib side plates 3 b and 3 c below the deck plate 2 between the U ribs 3 and the U ribs 3. A substantially gate-shaped concrete block 10 is formed, and the entire upper surface of the upper horizontal portion 10a of the concrete block 10 and the entire outer surfaces of the left and right legs 10b and 10c are the lower surface of the deck plate 2 and the left and right U-rib side plates, respectively. Work so that it adheres to the surface of 3b and 3c.

  A formwork material 20 such as an angle material is attached to the lower ends of the left and right legs 10b and 10c of the concrete block 10 and sprayed with a thickness of about 20 mm, for example. In addition, in order to ensure adhesion between the deck plate 2 and the left and right U-rib side plates 3b, 3c and the concrete, a locking bracket 21 such as a stud gibber is provided on the lower surface of the deck plate 2 and the U-rib side plates 3b, 3c in advance. Install it. Moreover, in order to prevent the fall of the material during and after spraying construction, the perforated board 22, such as an extended metal, is installed. The perforated plate 22 has a substantially portal shape corresponding to the substantially portal shape of the concrete block 10 and is disposed at an intermediate position of the spraying thickness.

  In the above-described configuration, the deck plate 2 is supported from below by the concrete block 10 having a substantially gate-shaped cross section extending between the left and right U ribs 3 and 3, and the corners of the deck plate 2 and the U rib 3 are reinforced. The local deformation of the deck plate 2 and the U rib 3 at the corner portion due to the wheel load can be suppressed, the local stress at the welded portion of the deck plate 2 and the U rib 3 can be relieved, and the fatigue life is improved. be able to.

  Furthermore, the concrete block 10 by such a spraying method can flexibly correspond to the steel plate slab bottom surface thickening reinforcement method of the existing truffle rib type steel slab. In addition, the reinforcement effect is acquired only by providing the leg part 10b * 10c of the concrete block 10 in the upper half of U-rib side board 3b * 3c.

  The material used for the concrete block 10 is a fiber-reinforced cement-based material that is lightweight, has a relatively large Young's modulus, and can prevent the block pieces from peeling off. Select appropriate concrete according to the required performance such as stress reduction effect, weight increase, and cost. Steel fiber reinforced concrete (SFRC), organic (polypropylene) fiber reinforced concrete (PPFRC), ultra high strength fiber reinforced concrete (UFC), multiple fine cracked fiber reinforced cement composite (HPFRCC), high tough fiber (high strength vinylon) Fiber) reinforced cement composite (ECC) is conceivable.

  ECC can be expected to bear the tensile force even after cracking occurs. Young's modulus is about 1/2 to 2/3 that of ordinary concrete. Compressive strength is slightly smaller than ordinary concrete. When comprehensively evaluating performance, good aesthetics, etc., an ECC that has excellent crack dispersion performance and can bear tensile stress is suitable. In addition, polymer concrete can also be used.

  Further, it is known that filling the inside of the U rib has an effect of reducing stress. As shown in FIG. 1, a cement system that is light in weight, has a relatively large Young's modulus, and does not cause breathing, as shown in FIG. Fill material 30. For example, high fluidity concrete or mortar, or cellular mortar, lightweight high fluidity concrete, or the like is used. It is considered that the deformation of the U-rib 3 is suppressed by filling the U-rib 3 with the cement-based material 30, which reduces the deformation of the steel deck. Accordingly, a slight gap is allowed between the lower surface of the deck plate 2 and the upper surface of the cementitious material 30.

  Next, FIG. 2 is a partial vertical sectional view showing an example of a reinforcing structure by the precast installation method of the present invention. In the case of the embodiment of FIG. 2A, a precast concrete block (hereinafter simply referred to as a precast block) 11 having a substantially gate-shaped cross section is disposed under the deck plate 2 between the U rib 3 and the U rib 3. The entire upper surface of the upper horizontal portion 11a of the block 11 and the entire outer surfaces of the left and right leg portions 11b and 11c are in contact with the lower surface of the deck plate 2 and the surfaces of the left and right U-rib side plates 3b and 3c, respectively. Secure to.

  The lower ends of the left and right legs 11b and 11c are fixed to the U-rib side plates 3b and 3c with a stopper such as a bolt 40. The bolt 40 may penetrate the leg parts 11b and 11c, or may only be used to prevent the fall by locking the lower ends of the leg parts 11b and 11c. The upper horizontal portion 11a and the left and right leg portions 11b and 11c are preferably in contact with each other, but at least at the point A on the upper surface and the points B and C (bolt fixing points) on both sides. Thus, a sufficient reinforcing effect can be obtained. At the time of construction, cement paste, mortar, or resin adhesive is applied in the vicinity of point A to achieve adhesion (contact) with the deck plate 2. In addition, even if it does not adhere | attach, if it is contacting, the deformation | transformation of the deck plate 2 will be suppressed by the restraining effect of the block 11, and the reinforcement effect will be acquired.

  In the case of the embodiment of FIG. 2B, a block 12 having an inverted U-shaped cross section is disposed under the deck plate 2 between the U rib 3 and the U rib 3, and point A at the arch top of the block 12, The left and right arch leg portions B and C are fixed so as to be in contact with the lower surface of the deck plate 2 and the surfaces of the left and right U-rib side plates 3b and 3c, respectively. Point contact, point B, point C may be point contact, or surface contact with a certain width.

  Also in this case, the lower ends of the left and right legs 12b and 12c are fixed to the U-rib side plates 3b and 3c with a stopper such as a bolt 40. Further, at the time of construction, cement paste, mortar or resin adhesive is applied in the vicinity of point A, and adhesion (contact) with the deck plate 2 is achieved. In addition, even if it does not adhere | attach, if it is contacting, the deformation | transformation of the deck plate 2 will be suppressed by the restraining effect of the block 12, and the reinforcement effect will be acquired.

  In the above-described configuration, the deck plate 2 is supported from below by the blocks 11 and 12 having a substantially gate-shaped cross section or a substantially inverted U-shaped cross section extending between the left and right U-ribs 3 and 3. In order to reinforce the corner portion of the steel plate, local deformation of the deck plate 2 and the U rib 3 at the corner portion due to the wheel load can be suppressed, and local stress at the welded portion of the deck plate 2 and the U rib 3 can be reduced. And the fatigue life can be improved.

  Furthermore, when a flat plate block is tightly fixed to the lower surface of the deck plate with a stud gibber or the like, the deck plate may be damaged. The left and right leg portions of the block-like blocks 11 and 12 can be fixed to the U rib 3 with bolts or the like, and the deck plate 2 is not damaged. Further, the corners of the deck plate 2 and the U rib 3 can be reinforced with the blocks 11 and 12 having a substantially gate-shaped cross section or a substantially inverted U-shaped cross section with respect to the flat block, and the corner angle due to the wheel load can be increased. A higher reinforcing effect can be obtained against local deformation of the deck plate 2 and the U-rib 3 in the section.

  If it is considered difficult to secure the adhesive strength of the adhesive surfaces of the precast blocks 11 and 12 only with an adhesive or the like, a stud gibber or the like is applied to the lower surface of the deck plate 2 and the precast block is fitted there. Can be used.

  The material used for the blocks 11 and 12 is a fiber-reinforced cement-based material that is lightweight, has a relatively large Young's modulus, and can prevent the block pieces from peeling off. Select appropriate concrete according to the required performance such as stress reduction effect, weight increase, and cost. Steel fiber reinforced concrete (SFRC), organic (polypropylene) fiber reinforced concrete (PPFRC), ultra high strength fiber reinforced concrete (UFC), multiple fine cracked fiber reinforced cement composite (HPFRCC), high tough fiber (high strength vinylon) Fiber) reinforced cement composite (ECC) is conceivable.

  ECC can be expected to bear the tensile force even after cracking occurs. Young's modulus is about 1/2 to 2/3 that of ordinary concrete. Compressive strength is slightly smaller than ordinary concrete. When comprehensively evaluating performance, good aesthetics, etc., an ECC that has excellent crack dispersion performance and can bear tensile stress is suitable. In addition, polymer concrete can also be used.

  The blocks 11 and 12 are manufactured at the factory, but when the block is manufactured, after pouring concrete or mortar into the formwork, a thin steel plate having openings such as perforated steel plates, lath nets, punching metal, and expanded metal. Can be made into blocks 11 and 12 having a small thickness and high rigidity by being embedded in concrete or mortar to form a sandwich structure.

  Next, it is known that filling the inside of the U-rib has an effect of reducing stress. As shown in FIG. 2, the U-rib 3 has a light weight, a relatively large Young's modulus, and no breathing cement. The system material 30 is filled. For example, high fluidity concrete or mortar, or cellular mortar, lightweight high fluidity concrete, or the like is used. It is considered that the deformation of the U-rib 3 is suppressed by filling the U-rib 3 with the cement-based material 30, which reduces the deformation of the steel deck. Accordingly, a slight gap is allowed between the lower surface of the deck plate 2 and the upper surface of the cementitious material 30.

  In order to further reduce the weight, a pipe or balloon 31 is inserted into the lower center of the U-rib 3 to secure a hollow portion, and a cement-based material 30 as a filler is placed on the upper and both sides of the U-rib 3. Fill. A pipe or balloon 31 is installed on the bottom plate 3 a of the U rib 3, and is fixed to the deck plate 2 and the side plates 3 b and 3 c by a stopper 32. The filling operation can be performed using the injection hole and the discharge hole.

  In addition, although the example applied to the reinforcement of the truffle rib type steel deck is shown above, the present invention is not limited to this, and the steel floor slab lower surface thickening method of the present invention can be applied to other vertical rib types. .

1 …… Steel deck 2 …… Deck plate 3 …… U rib (vertical rib)
4 ... Asphalt pavement 10 ... Sprayed concrete block 10a with a substantially gate-shaped section ... Upper horizontal part 10b, 10c ... Leg part 11 ... Precast concrete block 11a with a substantially portal-shaped section ... Upper horizontal part 11b, 11c ... Leg part 12 ... Precast concrete block 20 having an inverted U-shaped cross-section 20 ... Formwork material 21 such as an angle member ... Locking bracket 22 such as stud gibber ... Perforated plate 30 such as expanded metal ... Cement-based material ( Filler)
31 ... Pipe or balloon 32 ... Stopper 40 ... Bolt (stopper)

Claims (7)

  It is a steel floor slab reinforcement structure in which a plurality of vertical ribs are arranged at intervals on the bottom surface of the deck plate, under the deck plate between the vertical ribs and the vertical ribs, on the bottom surface of the deck plate and the left and right vertical rib side plate surfaces A steel floor characterized in that a concrete block having a substantially gate-shaped cross section is provided by spraying concrete by a spraying method so that the surface of the concrete block adheres to the bottom surface of the deck plate and the left and right vertical rib side plates. Plate reinforcement structure.   The reinforcing structure of a steel slab according to claim 1, wherein a perforated plate is embedded in the concrete block.   A steel plate slab reinforcement structure in which a plurality of vertical ribs are arranged at intervals on the bottom surface of the deck plate, and a precast concrete block with a substantially gate-shaped cross section under the deck plate between the vertical ribs and the vertical ribs. The steel floor slab reinforcement structure is installed so as to be in contact with the entire lower surface of the block and the surfaces of the left and right vertical rib side plates on the entire upper surface of the block and the entire surface of the block side surface.   It is a steel floor slab reinforcement structure in which a plurality of vertical ribs are arranged at intervals on the lower surface of the deck plate, and a precast concrete block having a substantially inverted U-shaped cross section is provided under the deck plate between the vertical ribs and the vertical ribs. A reinforcing structure for a steel slab characterized by being installed so as to be in contact with the lower surface of the deck plate and the surfaces of the left and right vertical rib side plates at the upper surface of the block top and a part of the block side surface, respectively.   5. The reinforcing structure of a steel slab according to claim 3, wherein the left and right leg portions of the precast concrete block are respectively fixed to the vertical rib side plate by a stopper.   The reinforcing structure according to any one of claims 1 to 5, wherein the concrete block is made of a fiber-reinforced cement-based material.   The reinforcing structure according to any one of claims 1 to 6, wherein the vertical rib is a vertical rib having a U-shaped trough-like cross section, and a filler is filled in the entire interior or in the upper part and both side parts in the interior. Steel slab reinforcement structure characterized by

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