JP2017061779A - Composite slab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite slab that is improved in fire resistance efficiency by reducing heat input during a fire and thus delaying a rise in temperature while suppressing material costs and construction costs from increasing.SOLUTION: A composite slab 1 applied with the present invention is provided as a floor structure of a building, and comprises a deck plate 2 having mountain parts 21 and valley parts 22 formed, a metal plate 3 provided on the reverse side of the deck plate 2, and concrete 4 provided over the deck plate 2. The metal plate 3 flexes away from a lower surface 2a of the deck plate 2 to thermally deforms and an air layer S is formed between the metal plate 3 and the deck plate 2 if a fire takes place.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a synthetic slab provided as a floor structure of a building.

  Conventionally, by forming a simple heat insulation space using the shape and structure of the deck plate for synthetic slabs, Patent Document 1, The fireproof structure of the synthetic floor slab disclosed in 2 is proposed.

  Here, the fireproof structure of the composite floor slab disclosed in Patent Document 1 is a composite floor slab structure in which a composite slab deck plate is installed on a beam and concrete is placed thereon, and a composite slab deck is provided. A flat steel lid is attached to the lower surface of the plate. And the fireproof structure of the synthetic floor slab disclosed by patent document 1 is formed in the time of a fire by forming the heat insulation space which closed the lower part of the convex part of the synthetic slab deck plate entirely with the steel cover plate. The rise in the temperature of the synthetic slab deck plate and concrete is suppressed.

  Moreover, the fireproof soundproof floor disclosed in Patent Document 2 is a deck material on the deck plate side of a deck plate concrete floor composed of a deck plate and concrete, and a face material made of a thermally expandable fireproof sheet and a noncombustible material or a semi-incombustible material. A fireproof and soundproof material is laminated as a laminated body. And the heat-expandable fireproof sheet of the fireproof soundproof floor disclosed in Patent Document 2 is a resin composition containing a heat-expandable inorganic material, a resin composition containing a thermoplastic resin or a rubber substance, or an epoxy resin. It is formed from the resin composition containing this.

JP 2004-332244 A JP 2002-173959 A

  However, the fireproof structure of the synthetic floor slab disclosed in Patent Document 1 is a steel lid plate on the lower surface of the concave portion of the deck plate for the synthetic slab by fixing means such as adhesion, screwing, riveting, or spot welding. Is fixed at the fixed point. And the fireproof structure of the synthetic floor slab disclosed in Patent Document 1 covers the lower surface of the concave portion of the synthetic slab deck plate, although a heat insulating space is formed in the convex portion of the synthetic slab deck plate. There is no steel lid attached.

  For this reason, the fireproof structure of the synthetic floor slab disclosed in Patent Document 1 is such that the steel lid is fixed to the lower surface of the concave portion of the synthetic slab deck plate so that the steel lid is a concave portion in the event of a fire. It will not be in a state of bending in a direction away from the lower surface of the plate. Moreover, the fireproof structure of the synthetic floor slab disclosed in Patent Document 1 is not provided with a steel lid so as to cover the lower surface of the concave portion, and in particular, between the concave portion and the steel lid. A heat insulation space is not formed.

  In addition, the fireproof soundproof floor disclosed in Patent Document 2 is a method of bonding to the deck plate using the adhesiveness of the fireproof soundproof material itself, and bonding the fireproof soundproof material and the deck plate using an adhesive or double-sided adhesive tape. Method, mechanically fixing the fireproof and soundproof material to the deck plate, method of sequentially stacking the layers constituting the fireproof and soundproof material on the bottom side of the deck plate, simply laying the fireproof and soundproof material on the bottom side of the deck plate A fireproof and soundproofing material is attached to the deck plate by a method such as:

  For this reason, the fireproof soundproof floor disclosed in Patent Document 2 is attached to the bottom surface of the deck plate by a method such as adhesion, so that the fireproof soundproof material is separated from the bottom surface of the deck plate in the event of a fire. It will not be bent in the direction. Further, the fireproof soundproof floor disclosed in Patent Document 2 has an enormous area for attaching an expensive thermally expandable fireproof sheet, which increases material costs, construction costs, and the like. The effect is small.

  Thus, the fireproof structure of the composite floor slab disclosed in Patent Documents 1 and 2 is not in a state where the steel lid plate or the fireproof soundproof material is bent in the direction away from the lower surface of the deck plate at the time of a fire. In particular, a sufficient air layer is not formed between the bottom surface of the deck plate and the steel cover plate or the fireproof and soundproofing material, and improvement of fireproof performance as a floor structure of a building has been a problem.

  Therefore, the present invention has been devised in view of the above-mentioned problems, and its object is to reduce heat input during a fire while suppressing an increase in material costs and construction costs. The object is to provide a synthetic slab with improved fire resistance by delaying the temperature rise.

  The composite slab according to the first aspect of the present invention is a composite slab provided as a floor structure of a building, wherein a deck plate in which peaks and valleys are formed, a metal plate provided below the deck plate, Concrete provided above the deck plate, and the metal plate is in a state of being thermally deformed in a direction away from the lower surface of the deck plate in the event of a fire, and an air layer is formed between the deck plate and the deck plate. It is formed.

  The composite slab according to a second aspect of the present invention is the composite slab according to the first aspect, wherein the metal plate is in contact with the lower surface of the deck plate at normal temperature and is bent and thermally deformed in a direction away from the lower surface of the deck plate in the event of a fire. It is characterized by becoming.

  The synthetic slab according to a third aspect of the present invention is the first aspect or the second aspect, wherein the metal plate extends from the peak portion formed on the upper side in the out-of-plane direction of the deck plate to the valley portion formed on the lower side. It is characterized by being provided so as to cover the lower surface of the valley portion of the deck plate in a continuous in-plane direction.

  In the synthetic slab according to a fourth aspect of the present invention, in any one of the first to third aspects, the metal plate is formed in a substantially flat plate shape, or is disposed at substantially the same position as the peak portion in an in-plane direction. The convex part and the concave part arrange | positioned in the substantially the same position as the said trough part are formed, It is characterized by the above-mentioned.

  The synthetic slab according to a fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, the metal plate is made of steel.

  The synthetic slab according to a sixth aspect of the present invention is characterized in that, in any one of the first to fifth aspects, only the side end portion in the in-plane direction of the metal plate is supported from below by the steel beam.

  According to the first to sixth inventions, in the event of a fire, the metal plate is bent and thermally deformed in a direction away from the lower surface of the deck plate, and an air layer is formed between the metal plate and the deck plate. Assuming that the heated back surface temperature and the amount of deflection in the fire resistance certification test do not exceed the limit values, the fire resistance performance of the synthetic slab can be improved.

  According to the first to sixth inventions, in particular, the amount of deflection of the metal plate increases due to heat input during a fire, so that an air layer is formed between the metal plate and the deck plate, As the heat input increases, the thickness of the air layer that functions as a heat insulating layer increases, so that the effect of reducing the heat input to the deck plate and concrete can be improved.

  According to 1st invention-6th invention, although the deflection amount of a metal plate increases with the heat input at the time of a fire, the deflection amount of a deck plate and concrete will not exceed a limit value, and the deflection amount of a deck plate and concrete It is possible to maintain the integrity of the deck plate and the concrete by suppressing.

  According to the first to sixth inventions, the heat input during a fire to the deck plate and the concrete is reduced by the heat insulation effect of the air layer without sticking an expensive thermally expandable fireproof sheet or the like to the deck plate. Therefore, metal plates that are easy to construct with inexpensive materials are used without the need for expensive heat-expandable fireproof sheets, etc., and fire resistance performance is improved while suppressing increases in material costs and construction costs. Is possible.

  According to 1st invention-6th invention, since the heat input at the time of a fire to a deck plate and concrete is reduced by the heat insulation effect of an air layer, wet fireproof coating can be reduced, wet fireproof coating It becomes possible to shorten the construction period for constructing the roof, and to suppress the increase in ceiling height due to the fireproof coating, and to expand the effective space in the room.

  According to the second to sixth inventions, the metal plate is brought into contact from below the deck plate, and the rigidity of the deck plate is improved, so that the amount of deflection of the deck plate and concrete at room temperature is suppressed. In addition, it is possible to improve the sound insulation performance of the composite slab, and omit or reduce the support work of the deck plate that will be the formwork material when placing concrete, thereby reducing the work period for placing concrete. It can be shortened.

It is a perspective view which shows the building in which the synthetic | combination slab to which this invention is applied is provided as a floor structure. It is a perspective view which shows the synthetic | combination slab and steel beam to which this invention is applied. It is a front view which shows the metal plate of a cross-sectional shape similar to the deck plate of the synthetic | combination slab to which this invention is applied. It is an enlarged front view which shows the deck plate and metal plate of the synthetic slab to which this invention is applied. It is a front view which shows the metal plate formed in the substantially flat shape of the synthetic | combination slab to which this invention is applied. It is a front view which shows the metal plate of the substantially same cross-sectional shape as the deck plate of the synthetic | combination slab to which this invention is applied. (A) is a front view which shows the metal plate by which only the side edge part of the in-plane direction of the synthetic | combination slab to which this invention is applied is supported by a steel beam, (b) is the side view. It is a front view which shows the metal plate of the state which the intermediate part of the in-plane direction bent and thermally deformed in the direction spaced apart from the lower surface of a deck plate at the time of the fire of the synthetic | combination slab to which this invention is applied. (A) is a front view which shows the state which the metal plate of the cross-sectional shape similar to a deck plate bent and thermally deformed at the time of the fire of the synthetic | combination slab to which this invention was applied, (b) is formed in the substantially flat plate shape. It is a front view which shows the state which the made metal plate bent and was thermally deformed. It is a front view which shows the fireproof certification test outline | summary of the synthetic | combination slab to which this invention is applied. It is an enlarged front view which shows the temperature distribution 120 minutes after a heating start by each analysis model of the heat conduction analysis which verifies the heat insulation effect of an air layer with the synthetic | combination slab to which this invention is applied. It is a graph which shows the log | history of the heating back surface temperature obtained from a heat conduction analysis in each analysis model of a heat conduction analysis. It is a graph which shows the relationship between the thickness of an air layer and a heating back surface temperature in each analysis model of heat conduction analysis.

  Hereinafter, the form for implementing the synthetic | combination slab 1 to which this invention is applied is demonstrated in detail, referring drawings.

  As shown in FIG. 1, the composite slab 1 to which the present invention is applied is provided as a floor structure of the building 8 mainly in a building 8 such as a house, a school, an office, or a hospital facility.

  The composite slab 1 to which the present invention is applied is formed in a substantially rectangular shape or the like at each level of the building 8, and each side edge 1 a formed in a substantially rectangular shape or the like is arranged in four directions, Each side edge 1a arranged in four directions is joined to and supported by a plurality of steel beams 7 such as H-shaped steels extending in a substantially horizontal direction.

  As shown in FIG. 2, the composite slab 1 to which the present invention is applied includes a deck plate 2 in which peaks 21 and valleys 22 are alternately formed, and a metal metal plate 3 provided below the deck plate 2. And concrete 4 provided above the deck plate 2.

  For the deck plate 2, for example, a steel material such as a 1.2 mm-thick thin steel plate conforming to the standard of JIS G 3352 is used. The deck plate 2 may be subjected to a rust-proofing treatment such as hot dip galvanization, or a thin steel plate such as weather-resistant steel or stainless steel, if necessary.

  As shown in FIG. 3, the deck plate 2 includes a plurality of crests 21 and a plurality of troughs 22 that are alternately continued in the in-plane direction X. The deck plate 2 is made of a thin steel plate bent in the out-of-plane direction Y, so that a plurality of crests 21 are formed on the upper side in the out-of-plane direction Y, and a plurality of crests 21 are formed on the lower side in the out-of-plane direction Y. A trough 22 is formed.

  In the deck plate 2, a crest portion 21 formed on the upper side in the out-of-plane direction Y and a trough portion 22 formed on the lower side are connected by a connecting portion 23 that extends in an in-plane direction Y so as to be inclined. In the deck plate 2, the distance D in the out-of-plane direction Y between the peak portion 21 and the valley portion 22 is, for example, about 50 mm, but not limited to this, the one having about 75 mm, about 120 mm, or the like is used. May be.

  As shown in FIG. 4, the deck plate 2 has a V-shaped groove 21 a formed in the approximate center of each peak portion 21 in the in-plane direction X and each connecting portion in the out-of-plane direction Y as necessary. A bent groove 23 a is formed above 23, and a trapezoidal groove 22 a is formed in the approximate center of each valley 22 in the in-plane direction X.

  The deck plate 2 is formed with the V-shaped groove 21a, the bent groove 23a, and the trapezoidal groove 22a, so that the bending rigidity in the out-of-plane direction Y is improved. In addition, the deck plate 2 has improved integrity with the concrete 4 by engaging the V-shaped groove 21 a, the bent groove 23 a and the trapezoidal groove 22 a with the concrete 4.

  In the deck plate 2, the concrete 4 is provided above the out-of-plane direction Y, and the metal plate 3 is provided below the out-of-plane direction Y. At this time, the deck plate 2 has a crest portion 21, a trough portion 22 and a connecting portion 23, and the concrete 4 side surface on which the concrete 4 is provided becomes the upper surface 2b, and the metal plate 3 side on which the concrete 4 is not provided. The surface becomes the lower surface 2a.

  As shown in FIG. 3, the concrete 4 is used by mixing cement, fine aggregate, coarse aggregate, water, admixture, and the like, and mortar may be used as necessary. The concrete 4 is placed on the upper surface 2 b side of the deck plate 2, hardened after a predetermined time on the upper surface 2 b side of the deck plate 2, and filled up to the valley portion 22 of the deck plate 2.

  For example, the concrete 4 has a thickness T of about 70 mm from the peak portion 21 of the deck plate 2 upward. If necessary, the concrete 4 is provided with a welded wire mesh 40 inside the crest portion 21 of the deck plate 2 while ensuring a covering thickness of, for example, 30 mm or more. The welded wire mesh 40 bears a tensile force and prevents cracks and the like of the concrete 4.

  For the metal plate 3, for example, a steel material such as a 1.2 mm-thick thin steel plate conforming to the standard of JIS G 3352 is used. The metal plate 3 may be made of any metal as long as it is bent and thermally deformed in the event of a fire. The metal plate 3 may be subjected to a rust prevention treatment such as hot dip galvanization as needed, or a thin steel plate such as weather resistant steel or stainless steel may be used.

  A thin steel plate or the like having a cross-sectional shape similar to that of the deck plate 2 is used for the metal plate 3, and a plurality of convex portions 31 and a plurality of concave portions 32 are alternately and continuously formed in the in-plane direction X. The metal plate 3 is formed of a thin steel plate or the like bent in the out-of-plane direction Y, so that a plurality of convex portions 31 are formed on the upper side of the out-of-plane direction Y and a plurality of lower sides of the out-of-plane direction Y. A recess 32 is formed.

  In particular, when a thin steel plate or the like having a cross-sectional shape similar to that of the deck plate 2 is used, the metal plate 3 has a convex portion 31 formed on the upper side in the out-of-plane direction Y and a lower side, as shown in FIG. The formed recess 32 is connected by an inclined portion 33 that extends in the out-of-plane direction Y with an inclination. At this time, the metal plate 3 does not have the V-shaped groove 21a, the bent groove 23a, and the trapezoidal groove 22a as in the deck plate 2, and the convex portion 31, the concave portion 32, and the inclined portion 33 are substantially flat. It is formed.

  The metal plate 3 is a thin steel plate or the like having a cross-sectional shape similar to that of the deck plate 2, but is not limited to this, and a thin steel plate or the like formed in a substantially flat plate shape is used as shown in FIG. May be. Further, as shown in FIG. 6, the metal plate 3 has V-shaped grooves 21 a, bent grooves 23 a, and trapezoidal grooves 22 a similar to the deck plate 2, as well as the convex portion 31, the concave portion 32, and the inclined portion 33 of the metal plate 3. A thin steel plate or the like that is formed and has substantially the same cross-sectional shape as the deck plate 2 may be used.

  As shown in FIG. 3, the metal plate 3 has a cross-sectional shape similar to that of the deck plate 2, or as shown in FIG. 6, the metal plate 3 has substantially the same cross-sectional shape as the deck plate 2. The convex portion 31 of the metal plate 3 is fitted into the peak portion 21 of the plate 2 from below. At this time, the metal plate 3 has a convex portion 31 disposed at substantially the same position as the peak portion 21 of the deck plate 2 in the in-plane direction X, and at approximately the same position as the valley portion 22 of the deck plate 2 in the in-plane direction X. A recess 32 is disposed.

  As shown in FIGS. 3, 5, and 6, the metal plate 3 is continuously continuous in the in-plane direction X from the peak portion 21 to the valley portion 22 of the deck plate 2, and the lower surface 2 a of the deck plate 2 is entirely covered. It is provided so as to cover from below. At this time, the metal plate 3 is provided so as to cover not only the lower surface 2 a of the peak portion 21 of the deck plate 2 but also the lower surface 2 a of the valley portion 22 of the deck plate 2, thereby covering the entire surface in the in-plane direction X. Will be provided continuously.

  As shown in FIGS. 3 and 5, the metal plate 3 is entirely in the valley portion 22 of the deck plate 2 regardless of whether the metal plate 3 has a cross-sectional shape similar to the deck plate 2 or a substantially flat plate shape. The abutting surface 30 is formed by abutting against the lower surface 2a. Further, as shown in FIG. 6, when the metal plate 3 has substantially the same cross-sectional shape as the deck plate 2, the metal plate 3 is brought into contact with a part of the lower surface 2 a of the valley portion 22 and the connecting portion 23 of the deck plate 2. A contact surface 30 is partially formed.

  As shown in FIG. 7, the metal plate 3 is a portion where the composite slab 1 is joined to the steel beam 7, and is joined by a joining method such as joining by a punching plug welding, joining by a driving rod, or joining by a headed stud. The side end portion 3a in the in-plane direction X is joined to the steel beam 7 and supported. In the in-plane direction X, the metal plate 3 is not supported by the steel beam 7 in the center side intermediate portion 3b, and only the side end portion 3a in the in-plane direction X is sandwiched between the deck plate 2. The steel beam 7 is supported from below.

  As shown in FIG. 3, the metal plate 3 is fixed or stuck to any lower surface 2 a of the peak portion 21, the valley portion 22, and the connecting portion 23 of the deck plate 2, particularly in the intermediate portion 3 b in the in-plane direction X. It is brought into contact with the lower surface 2a of the deck plate 2 without being joined by wearing or the like. The metal plate 3 is not limited to this, and may be provided as not being bonded to the deck plate 2 in a state of being separated from the lower surface 2a of the deck plate 2 without being in contact with the lower surface 2a of the deck plate 2. .

  As shown in FIG. 7, only the side end 3 a in the in-plane direction X of the metal plate 3 is supported by the steel beam 7 from below with the deck plate 2. Further, as shown in FIG. 8, the metal plate 3 is not joined to the lower surface 2 a of the deck plate 2 at the intermediate portion 3 b in the in-plane direction X. At this time, the metal plate 3 is in contact with the lower surface 2a of the deck plate 2 at room temperature, but is in particular separated from the lower surface 2a of the deck plate 2 by bending during a fire.

  As shown in FIG. 9, the metal plate 3 is in a state of being thermally deformed by being bent in a direction away from the lower surface 2a of the deck plate 2 in a fire from a state where it is in contact with the lower surface 2a of the deck plate 2 at room temperature. . The metal plate 3 is bent and thermally deformed in the event of a fire, and an air layer S is formed between the metal plate 3 and the deck plate 2 while being separated from the lower surface 2 a of the deck plate 2.

  Since the metal plate 3 is in a state of being thermally deformed in the event of a fire, a new air layer S is formed particularly below the peak portion 21 and the valley portion 22 of the deck plate 2 as shown in FIG. Is done. Further, the metal plate 3 is in a state of being thermally deformed in the event of a fire, thereby increasing the thickness of the air layer S formed in advance below the peak portion 21 of the deck plate 2 as shown in FIG. 9B. In this case, a new air layer S may be formed only below the valley portion 22 of the deck plate 2.

  In the composite slab 1 to which the present invention is applied, when the concrete 4 is placed, after the deck plate 2 functions as a formwork material and the concrete 4 is hardened, the deck plate 2 bears a tensile force and the concrete 4 Bears the compressive force. The composite slab 1 to which the present invention is applied not only has a large heat capacity of the concrete 4 itself, but also the water inside the concrete 4 evaporates, thereby delaying the temperature rise of the entire composite slab 1. .

  Here, in the fire resistance certification test of the synthetic slab 1, the two items of the heating back surface temperature and the amount of deflection are the main evaluation items, and the values of these two items do not exceed the limit values until the heating is completed for a predetermined time. Is required. Then, as shown in FIG. 10, this fire resistance certification test sets the span length, loading point, loading load P, etc. of the synthetic slab 1, and sets the synthetic slab 1 for a predetermined time such as 30 minutes, 1 hour, 2 hours, etc. After heating from below, two items of the heated back surface temperature and the amount of deflection are measured.

  The heated back surface temperature measures the temperature of the back surface opposite to the heated surface on which the composite slab 1 is heated. In the fire resistance certification test, the influence of the load capacity of the composite slab 1 or the length of the span length is affected. It will be hardly received. On the other hand, the amount of deflection is affected by the magnitude of the loaded load of the composite slab 1 or the length of the span length. In particular, even when the loaded load is large or the span length is long, the amount of deflection is large. Is required not to exceed the limit value.

  As shown in FIG. 9, the composite slab 1 to which the present invention is applied is in a state in which the metal plate 3 is bent and thermally deformed in a direction away from the lower surface 2a of the deck plate 2 particularly in the event of a fire. 2, an air layer S having a predetermined thickness d is formed in the out-of-plane direction Y. At this time, in the synthetic slab 1 to which the present invention is applied, the air layer S between the metal plate 3 and the deck plate 2 functions as a heat insulating layer that reduces heat input during a fire.

  In the composite slab 1 to which the present invention is applied, although the amount of deflection of the metal plate 3 increases due to heat input at the time of fire, the air layer S between the metal plate 3 and the deck plate 2 functions as a heat insulating layer, and the deck The heat input to the plate 2 and the concrete 4 is reduced. In the composite slab 1 to which the present invention is applied, the heat input to the deck plate 2 and the concrete 4 at the time of fire is reduced by the heat insulating effect of the air layer S, so that the temperature rise of the deck plate 2 and the concrete 4 is delayed. .

  At this time, as for the synthetic slab 1 to which the present invention is applied, an increase in the heated back surface temperature in the fire resistance certification test is suppressed by delaying the temperature rise of the deck plate 2 and the concrete 4. The composite slab 1 to which the present invention is applied can suppress the increase in the heated back surface temperature in the fire resistance certification test, so that the deck plate 2 and the concrete can be used even when the load is large or the span length is long. The amount of deflection of 4 does not exceed the limit value.

  The composite slab 1 to which the present invention is applied is in a state where the metal plate 3 is bent and thermally deformed in a direction away from the lower surface 2 a of the deck plate 2 in the event of a fire, and an air layer S is formed between the metal plate 3 and the deck plate 2. By being formed, it is possible to improve the fire resistance of the synthetic slab 1 on the assumption that the heated back surface temperature and the amount of deflection in the fire resistance certification test do not exceed the limit values.

  In the synthetic slab 1 to which the present invention is applied, the air layer S between the metal plate 3 and the deck plate 2 is increased particularly when the amount of deflection of only the metal plate 3 is increased due to heat input during a fire. At this time, in the synthetic slab 1 to which the present invention is applied, as the heat input to the metal plate 3 increases, the thickness d of the air layer S functioning as a heat insulating layer increases, so that the deck plate 2 and the concrete 4 The effect of reducing the heat input to can be improved.

  In the composite slab 1 to which the present invention is applied, the amount of deflection of the metal plate 3 increases due to heat input during a fire, but the amount of deflection of the deck plate 2 and the concrete 4 does not exceed the limit value. At this time, in the composite slab 1 to which the present invention is applied, the deflection amount of the deck plate 2 and the concrete 4 is suppressed, and the deck plate 2 and the concrete 4 are difficult to be separated from each other. It is possible to maintain unity.

  In the synthetic slab 1 to which the present invention is applied, the heat input to the deck plate 2 and the concrete 4 at the time of a fire is prevented from the heat insulation effect of the air layer S without sticking an expensive heat-expandable fireproof sheet or the like to the deck plate 2. Is reduced. The synthetic slab 1 to which the present invention is applied does not require an expensive heat-expandable fireproof sheet or the like, and the metal plate 3 that is easy to construct with an inexpensive material is used, thereby increasing the material cost and construction cost. It becomes possible to improve fireproof performance while suppressing.

  In the synthetic slab 1 to which the present invention is applied, the heat input to the deck plate 2 and the concrete 4 at the time of fire can be reduced by the heat insulating effect of the air layer S, and the wet fireproof coating can be reduced. It is possible to shorten the construction period for applying the fireproof coating. In addition, the composite slab 1 to which the present invention is applied can reduce the fireproof coating on the deck plate 2, thereby suppressing an increase in ceiling height due to the fireproof coating and expanding the indoor effective space. .

  In the composite slab 1 to which the present invention is applied, since the rigidity of the deck plate 2 is improved by contacting the metal plate 3 from below the deck plate 2, the deflection amount of the deck plate 2 and the concrete 4 at normal temperature is reduced. In addition to being suppressed, the sound insulation performance of the synthetic slab 1 can be improved. In addition, the composite slab 1 to which the present invention is applied improves the rigidity of the deck plate 2 that becomes a formwork material when placing the concrete 4, so the support work for the deck plate 2 is omitted or reduced, and the concrete 4 This makes it possible to shorten the construction period for placing the.

  The synthetic slab 1 to which the present invention is applied aims to improve the fire resistance by reducing the heat input to the deck plate 2 and the concrete 4 at the time of a fire and delaying the temperature rise. Here, the heat conduction analysis was performed in order to examine the heat insulation effect of the air layer S formed between the metal plate 3 and the deck plate 2 because the metal plate 3 was bent and thermally deformed during a fire.

  In this heat conduction analysis, the effect of the air layer S formed between the metal plate 3 and the deck plate 2 on the temperature in the cross section of the synthetic slab 1 was verified for a fire resistance certification test. The analysis cross section is a composite with a total thickness of 120.0 mm by placing two deck plates 2 and metal plates 3 as shown in FIG. Slab 1 was targeted. In this heat conduction analysis, the thickness d of the air layer S was used as an analysis variable, and the heating conditions were set for heating for 2 hours in accordance with the ISO 834 standard heating curve.

  In this heat conduction analysis, as shown in FIG. 11, a plurality of analysis models were set by changing the thickness d of the air layer S. In each analysis model, assuming that the thickness d of the air layer S does not change over time, the air layer S was simulated by providing elements in which the thermal conductivity, specific heat, density, and the like of the air were set. In addition, the thermophysical property value of each material used for the analysis was the value listed in the steel structure fireproof design guidelines.

  The analysis model in which the metal plate 3 is not provided below the deck plate 2 (FIG. 11A) and the analysis model in which the metal plate 3 is joined to the deck plate 2 (FIG. 11B) are the air layer S Is formed (thickness d = 0). 11 (c) and 11 (d) are intended for the synthetic slab 1 to which the present invention is applied, and the thickness d of the air layer S = 10 mm (FIG. 11 (c)). ) And the thickness d of the air layer S = 100 mm (FIG. 11D). The temperature display is as shown in the legend of FIG.

  According to the results of the heat conduction analysis, in the analysis models of FIGS. 11A and 11B, since the thickness d = 0 of the air layer S, the deck plate 2 and the concrete 4 in the vicinity thereof are 800 ° C. It can be seen that the temperature is very high, about ˜1100 ° C. On the other hand, in the analysis model of FIG. 11C, the thickness d of the air layer S serving as the heat insulating layer is 10 mm, and the deck plate 2 and the concrete 4 in the vicinity thereof are kept at about 200 ° C. to 300 ° C. 11D, the thickness d of the air layer S is 100 mm, and the deck plate 2 and the concrete 4 in the vicinity thereof are kept at about 100 ° C. to 200 ° C.

  FIG. 12 shows the history of the heated back surface temperature obtained from the heat conduction analysis, with the heated back surface temperature above the peak 21 of the deck plate 2 as the vertical axis and the time as the horizontal axis. Here, as shown in FIG. 12, the heated back surface temperature is about 280 ° C. when the thickness d = 0 of the air layer S at a time point 120 minutes after the start of heating, whereas the air layer S Is about 70 ° C. when the thickness d = 10 mm, and about 25 ° C. when the thickness d of the air layer S = 100 mm. As shown in FIG. 13, the result of the heat conduction analysis is shown as a relationship between the thickness d of the air layer S and the heated back surface temperature. The larger the thickness d of the air layer S, the higher the heated back surface temperature. descend.

  In the fire resistance certification test, the limit value of the heated back surface temperature is specified as an initial temperature + 140 ° C., and the synthetic slab 1 to which the present invention is applied has a predetermined thickness as shown in FIGS. When the air layer S of d is formed, when the thickness d of the air layer S is 10 mm, the heated back surface temperature decreases by about 210 ° C., and when the thickness d of the air layer S is 100 mm, the heated back surface temperature is 255. It can be seen that the temperature does not exceed the limit value of the heated back surface temperature in the fire resistance certification test because it decreases by about ℃.

  Thus, the composite slab 1 to which the present invention is applied is formed between the metal plate 3 and the deck plate 2 because the metal plate 3 is bent and thermally deformed in the event of a fire from the result of the heat conduction analysis. It has been verified that the air layer S exhibits a heat insulating effect and can achieve excellent fire resistance.

  As mentioned above, although the example of embodiment of this invention was demonstrated in detail, all the embodiment mentioned above showed only the example of actualization in implementing this invention, and these are the technical aspects of this invention. The range should not be interpreted in a limited way.

1: Composite slab 1a: Side edge 2: Deck plate 2a: Lower surface 2b: Upper surface 21: Mountain portion 21a: V-shaped groove 22: Valley portion 22a: Trapezoidal groove 23: Connecting portion 23a: Bending groove 3: Metal plate 3a: Side end part 3b: Intermediate part 30: Contact surface 31: Convex part 32: Concave part 33: Inclined part 4: Concrete 40: Welded wire mesh 7: Steel beam 8: Building S: Air layer X: In-plane direction Y: Surface Outward direction

Claims (6)

A synthetic slab provided as a floor structure of a building,
A deck plate formed with peaks and valleys, a metal plate provided below the deck plate, and concrete provided above the deck plate,
The synthetic slab characterized in that the metal plate is in a state of being thermally deformed by being bent away from the lower surface of the deck plate in the event of a fire, and an air layer is formed between the metal plate and the deck plate. 2. The composite slab according to claim 1, wherein the metal plate is brought into contact with the lower surface of the deck plate at a normal temperature and is in a state of being thermally deformed in a direction away from the lower surface of the deck plate in the event of a fire. . The metal plate is continuous in the in-plane direction from the peak portion formed on the upper side in the out-of-plane direction of the deck plate to the valley portion formed on the lower side, and the lower surface of the valley portion of the deck plate is It is provided so that it may cover. The synthetic | combination slab of Claim 1 or 2 characterized by the above-mentioned. The metal plate is formed in a substantially flat plate shape, or is formed with a convex portion that is disposed at substantially the same position as the peak portion in the in-plane direction and a concave portion that is disposed at substantially the same position as the valley portion. The synthetic slab according to any one of claims 1 to 3, wherein: The synthetic metal slab according to any one of claims 1 to 4, wherein a steel material is used for the metal plate. 6. The composite slab according to claim 1, wherein only the side end portion in the in-plane direction of the metal plate is supported from below by the steel beam.