JP2012026083A - Viaduct back surface fire-resisting sound absorption structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a viaduct back surface fire-resisting sound absorption structure which has not only a noise reducing function of absorbing and reducing traffic noise from a road under a viaduct but also a fire resisting function of protecting the viaduct from fire heat when a fire such as a vehicle fire occurs under the viaduct.SOLUTION: The viaduct back surface fire-resisting sound absorption structure includes: a lower side frame body 2 which forms a channel shape opened on the upper side; an upper side frame body 3 which forms a channel shape opened on the lower side to form a frame body with the lower side frame body 2, and has a heat insulation material support part 3a extending in an inner side direction at the lower part; a sound absorption material 4 which is arranged inside the lower side frame body 2 and forms a flat plate shape; a heat insulation material 5 which is supported by the heat insulation material support part 3a and disposed inside the upper side frame body 3, is resistant to heat at or above 1100°C, forms a flat plate shape, and is for protecting the viaduct from fire heat by a fire under the viaduct; and an upper side frame body protecting heat insulation material 6 which is resistant to the heat at or above 1100°C, and is for protecting the upper side frame body 3 from the fire heat.

Description

  The present invention is installed on the back side of a viaduct such as an elevated road or an elevated railway with a road underneath (underlying), and absorbs and reduces structural noise from the viaduct itself and traffic noise from the road. In addition to a noise reduction function, the present invention relates to a viaduct backside fireproof sound absorbing structure that also has a fireproof function that protects the viaduct from fire heat when, for example, a vehicle fire occurs on the road.

  In a viaduct such as an elevated road or an elevated railway with a road underneath it, noise from a car traveling on the lower road may be reflected on the back of the viaduct and increase the noise around the road.

  For this reason, a sound-absorbing structure that is installed on the back surface of a viaduct with a road underneath and absorbs structural noise from the viaduct itself and traffic noise from the road below has been proposed (Patent Document 1: Japanese Patent No. 3601575). This conventional sound absorbing structure will be described with reference to FIG. FIG. 6 is a cross-sectional view of a conventional sound absorbing structure.

  This conventional sound-absorbing structure is suspended downwardly under a viaduct and connected to each other, and is attached to a hollow frame composed of a frame 51 and a perforated plate 52, and an interior thereof. It consists of fibrous sound-absorbing materials 53 and 54 that are arranged in two layers and have a total thickness of 50 to 110 mm. The frame 51 is made of an extruded aluminum material or the like, covers the back and side surfaces of the fibrous sound absorbing materials 53 and 54, and is provided with connecting portions 55 and 56 for connecting the sound absorbing structures to both side edges. Yes. The porous plate 52 is made of expanded metal or punching metal having an appropriate aperture ratio, and is directly connected to the frame 51 and covers the front and side surfaces of the fibrous sound absorbing materials 53 and 54.

  The fibrous sound-absorbing materials 53 and 54 are layers of fibrous sound-absorbing materials such as glass wool, rock wool, and non-woven fabric, and are covered and laminated with a film such as polyvinyl fluoride. Further, 58 is a protective material such as a glass cloth provided as appropriate along the inner surface of the porous plate 52 to protect the sound absorbing materials 53 and 54, 59 is a surface air layer, and 60 is a gap constituting a back air layer. A hanging groove 57 for suspension is formed in the longitudinal direction in the central portion of the frame body 51, and a head of a suspension bolt (not shown) is fitted into the groove 51, and a plurality of them are mutually connected in the width direction and longitudinal direction of the viaduct. Each sound absorbing structure is suspended below the viaduct steel bridge girder (main girder) in a connected state.

  In this way, conventionally, a sound absorbing structure in which a fibrous sound absorbing material is arranged in a hollow frame is installed on the back of a viaduct with a road underneath, so that the sound of the structure from the viaduct itself and traffic from the lower road Noise is absorbed to reduce noise.

  By the way, in recent years, there have been many accidents in which general bridges and viaducts receive fires due to vehicle accidents or suspicious fires under the bridge. When such an accident occurs, in the worst case, the collapse of the viaduct can be considered, and even if it does not collapse, long-term traffic regulation is conducted for investigation and restoration, and there is a great deal of social life and economic activity. Will have an impact.

  Under such circumstances, the conventional sound absorbing structure used for the purpose of noise reduction has been adopted in the viaduct in the city center so far, but has fire resistance (fire resistance function) against fire under the viaduct. Not in. On the other hand, as a means to protect civil engineering structures such as viaducts from fires, although there is no actual example, it is conceivable to directly apply heat insulating material to the bridge girder surface of the viaduct or the back of the floor slab. It is considered small.

Japanese Patent No. 3601575

  Therefore, an object of the present invention is to install on the back of a viaduct such as an elevated road or an elevated railway where a road is provided underneath, and normally absorbs structural noise from the viaduct itself and traffic noise from the road. Another object of the present invention is to provide a viaduct backside soundproof structure that has a noise reduction function that reduces noise, and also has a fireproof function that protects the viaduct from fire heat when a fire occurs due to a vehicle fire under the viaduct.

  In order to solve the above problems, the present invention takes the following technical means.

  The invention of claim 1 is a viaduct backside soundproof structure which is connected and suspended below a viaduct bridge girder and is installed so as to surround the entire backside of the viaduct. An upper frame having a heat insulating material supporting portion extending inward at a lower portion, and a lower frame formed in a channel shape opened in the lower side and having a channel shape opened to the lower side; A sound-absorbing material arranged in a frame and having a flat plate shape, and supported by the heat insulating material support portion in the upper frame and having a heat resistance of 1100 ° C. or more, forming a flat plate shape, and fire under a viaduct And a heat insulating material for protecting the viaduct from fire heat caused by the above and a heat insulating material for protecting the upper frame body having a heat resistance of 1100 ° C. or higher and protecting the upper frame body from fire heat. It is a featured fire-resistant sound absorbing structure on the back of a viaduct

  According to a second aspect of the present invention, in the viaduct backside fireproof sound absorbing structure according to the first aspect, the heat insulating material for protecting the upper frame has a flat plate shape, and includes the heat insulating material supporting portion and the lower side of the upper frame. It is arrange | positioned in the said lower side frame body so that the whole may be covered.

  A third aspect of the present invention is the highly bridged backside soundproof structure according to the first or second aspect, wherein the heat insulating material and the heat insulating material for protecting the upper frame are made of a ceramic fiber blanket. Is.

  The viaduct backside soundproof sound absorbing structure according to the present invention includes a sound absorbing material arranged in the lower frame, so that it normally absorbs the noise of the structure from the viaduct itself and the traffic noise from the road below the viaduct. Reduction can be achieved. Moreover, the viaduct backside fireproof sound absorbing structure according to the present invention has a heat insulating material having a heat resistance of 1100 ° C. or higher and a heat resistance of 1100 ° C. or higher, disposed in the upper frame inside the lower frame. Since the upper frame body is provided with an upper frame body protection heat insulating material for protecting the upper frame body from fire heat, when a fire occurs due to a vehicle fire under a viaduct, the viaduct is protected from fire heat and the strength of the floor slab It is possible to prevent damage to the viaduct such as lowering, strength reduction and deformation of the steel bridge girder (main girder).

It is explanatory drawing for demonstrating the attachment to the viaduct of the viaduct back surface soundproof structure according to the present invention. It is sectional drawing which shows the viaduct back surface fireproof sound absorption structure by one Embodiment of this invention. It is sectional drawing which shows the test body of a comparative example (type A). It is sectional drawing which shows the test body of another comparative example (type C). It is a top view which shows a mode that six types of test bodies have been arrange | positioned in the large sized horizontal heating furnace in a fireproof experiment. It is sectional drawing of the conventional sound absorption structure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory view for explaining attachment of a viaduct backside soundproof structure according to the present invention to a viaduct.

  In FIG. 1, reference numeral 10 denotes a viaduct such as an elevated road or an elevated railway, and a road (not shown) is provided below the viaduct 10 extending in the depth direction of the figure. 11 is a floor slab, 12 is a steel bridge girder (main girder), and the upper structure of the viaduct 10 is composed of a floor slab 11 and a plurality of bridge girders 12. These bridge girders 12 extend in the longitudinal direction of the viaduct 10 (the depth direction in the figure), and the adjacent bridge girders 12 are connected to each other by a truss-shaped counter tilt structure 13 at a predetermined interval pitch in the longitudinal direction.

  In addition, in order to attach a plurality of viaduct backside soundproof structures 1 to be described later, the lower ends of each bridge girder 12 are made of steel via a steel horizontal member 14 at a predetermined interval pitch in the longitudinal direction of the bridge girder 12. A suspension member 15 is attached. A horizontal beam 16 made of H-shaped steel extending in the width direction of the viaduct 10 (the width direction of the floor slab 11) is supported by these suspension members 15. The cross beams 16 are arranged at a predetermined pitch in the longitudinal direction of the viaduct (longitudinal direction of the bridge beam 12).

  And, to these horizontal beams 16, a plurality of viaduct backside soundproof structures 1 are connected and attached in a panel shape, so that the entire backside of the viaduct 10 is surrounded along the longitudinal direction of the viaduct 10. A viaduct backside soundproof structure 1 is installed. Reference numeral 12a denotes a lower flange of the bridge girder 12. The distance from the lower surface of the lower flange 12a of the bridge girder 12 to the upper surface of the viaduct backside soundproof structure 1 is set to about 600 mm, for example.

  FIG. 2 is a cross-sectional view showing a viaduct backside soundproof structure according to an embodiment of the present invention.

  As shown in FIG. 2, the viaduct backside soundproof structure 1 according to this embodiment includes a lower frame 2, an upper frame 3, a sound absorbing material 4 disposed in the lower frame 2, and an upper frame. The heat insulating material 5 arrange | positioned in the body 3 and the heat insulating material 6 for upper frame body protection are provided. Hereinafter, each of these components will be described.

  The lower frame 2 has a channel shape with a U-shaped cross section that opens upward, and is made of a steel plate such as a high corrosion-resistant hot-dip galvanized steel plate. A large number of holes having a diameter of about 5 to 10 mm are formed on the lower surface of the lower frame body 2, and a glass cloth (glass cloth) (not shown) is attached as a sound absorbing material protective material (surface protective material).

  A sound absorbing material 4 having a predetermined thickness made of rock wool, glass wool or the like is disposed on the lower surface of the lower frame 2 on which the glass cloth is attached. The sound-absorbing material 4 is disposed in a state of being wrapped in polyvinyl fluoride (not shown) in order to improve waterproofness and weather resistance.

  On the sound absorbing material 4 in the lower frame 2, an upper frame protecting heat insulating material 6 is placed in a flat plate-like layer. This upper frame body protection heat insulating material 6 has a heat resistance of 1100 ° C. or more, and is intended to protect the upper frame body 3 from fire heat due to fire under a viaduct, from a ceramic fiber blanket having a predetermined thickness. It has become. The ceramic fiber blanket is a felt-like heat insulating material made of, for example, alumina silicate fiber.

  Next, the upper frame 3 is formed in a channel shape having a U-shaped cross section that opens downward, and is made of a steel plate such as a highly corrosion-resistant hot-dip galvanized steel plate, and has a predetermined length with the lower frame 2. A frame body (outer frame body) is formed. The upper frame 3 includes a flat upper surface portion, side surface portions that vertically fall from both ends in the width direction on the upper surface, and a heat insulating material support portion 3a that extends horizontally inward from the lower end of each of the side surface portions. It has a channel shape consisting of

  In the upper frame 3, the heat insulating material 5 is supported by the heat insulating material supporting portion 3 a and is disposed in a flat plate-like layer. This heat insulating material 5 has a heat resistance of 1100 ° C. or higher, is for protecting the viaduct 10 from fire heat due to a fire under the viaduct 10, and is made of a ceramic fiber blanket having a predetermined thickness.

  From the viewpoint of safety against fire under a viaduct, the temperature of the lower flange 12a position of the bridge girder 12 is determined with respect to fire heat of 1100 ° C. × 90 minutes in consideration of strength reduction of the steel material at high temperature. The target is to set the temperature to 350 ° C. or lower. From this point, the heat insulating material 5 and the upper frame body protecting heat insulating material 6 have heat resistance of 1100 ° C. or higher.

  And the side part of the lower frame 2 in which the sound absorbing material 4 and the upper frame body protection heat insulating material 6 are arranged, and the side part of the upper frame 3 in which the heat insulating material 5 are arranged have a heat resistance of 1100 ° C. or higher. And are connected by bolting with bolts 8 at a predetermined interval pitch via a band-shaped ceramic sheet 7 extending along the longitudinal direction of both frame bodies 2 and 3.

  Thereby, in this embodiment, it is made to cover the whole lower side of upper frame 3 including heat insulating material support part 3a with heat insulating material 6 for upper frame protection arranged in a lower frame. .

  In FIG. 2, the symbol W indicates the width of the viaduct backside soundproof structure 1, the symbol h indicates the height of the viaduct backside soundproof structure 1, and the symbol h1 indicates the height of the upper frame 3. (Refer to Examples described later).

  Thus, the viaduct backside soundproof structure 1 according to this embodiment includes the sound absorbing material 4 disposed in the lower frame 2, and normally absorbs the sound of the structure from the viaduct itself, It is possible to reduce traffic noise by absorbing traffic noise from the road under the viaduct and preventing reflection to the road periphery.

  Further, the viaduct backside fireproof sound absorbing structure 1 has a heat insulating material 5 having a heat resistance of 1100 ° C. or higher arranged in the upper frame 3, a heat resistance of 1100 ° C. or higher, The upper side which prevented the temperature rise by the heat of a heat insulating material support part 3a, and suppressed the thermal deformation by the heat of a fire of the upper side frame 3, and kept the cross-sectional shape of the upper side frame 3 in which the heat insulating material 5 was accommodated. And a frame body heat insulating material 6. As a result, in the event of a fire due to a vehicle fire under a viaduct, unlike the conventional case, the viaduct 10 is protected from fire heat and damage to the viaduct such as a decrease in the strength of the floor slab 11 and a decrease in strength or deformation of the bridge girder 12 is prevented. Can be prevented.

  A fireproof experiment for confirming the fireproof performance of the viaduct backside soundproof structure according to the present embodiment was conducted. As shown in Table 1, six types of test bodies were manufactured, as shown in Table 1, including types A1 and A2 of comparative examples, types B1 and B2 of examples, and types C1 and C2 of comparative examples.

  The configuration of the test bodies of types B1 and B2, which are examples, is as shown in FIG. Among these, the specification of each component of type B1 is as follows. The lower frame 2 is made of a highly corrosion-resistant hot-dip galvanized steel sheet having a thickness of 0.8 mm (the lower surface is punched), and the upper frame 3 is made of a highly corrosion-resistant hot-dip galvanized steel sheet having a thickness of 1.6 mm. The dimension W is 490 mm, the dimension h is 105 mm, the dimension h 1 is 60 mm, the dimension h 2 is 55 mm, and the length is 2000 mm. The specifications of the lower frame body 2 and the upper frame body 3 are the same for the other test bodies. The sound absorbing material 4 has a thickness of 50 mm and is made of rock wool. The heat insulating material 6 for protecting the upper frame body is made of a ceramic fiber blanket having a thickness of 12.5 mm and heat resistance of 1300 ° C. The heat insulating material 5 is made of a ceramic fiber blanket having a thickness of 25 mm and heat resistance of 1300 ° C. Type B2 has the same specifications as type B1 except that the thickness of the heat insulating material 5 is 50 mm (25 mm × 2 layers).

  Next, the configuration of the type A1 and A2 test bodies, which are comparative examples, is as shown in FIG. The difference between the type A1 and A2 specimens and the type B1 and B2 specimens of the examples is that the type A1 and A2 specimens are provided with the heat insulating material 5 and the upper frame body protecting heat insulating material 6. There is no point. The difference between types A1 and A2 is that the type of the sound absorbing material protecting material is different (see Table 1).

  Moreover, the structure of the test body of type C1, C2 which is another comparative example is as showing in FIG. The difference between the type C1 and C2 test bodies and the type B1 and B2 test bodies as examples is that the type C1 and C2 test bodies do not include the upper frame body protection heat insulating material 6. The difference between the types C1 and C2 is that the thickness of the heat insulating material 5 is different (C1: 25 mm, C2: 50 mm (25 mm × 2 layers)).

  FIG. 5 is a plan view showing a state in which six types of test bodies are arranged in a large horizontal heating furnace in a fireproof experiment. The refractory experiment was conducted using a large horizontal heating furnace whose upper surface could be opened. As shown in FIG. 5, the six types of test specimens are brought into close contact and arranged in a single flat panel shape, and two parallel cross beams 16 '(of the same specifications as those used when installing on an actual viaduct) It was fixed to H-shaped steel and suspended, and was installed in a lid shape on the upper surface of a large horizontal heating furnace, and fireproof lids were also installed on both sides to cover the furnace upper surface.

  In this fire resistance experiment, the six types of specimens were heated at a temperature of 1100 ° C. for 90 minutes using a known hydrocarbon curve having a temperature-time relationship assuming an oil fire. Then, assuming the temperature of the cross beam 16 ′ to which the six types of test bodies are fixed, the position of the lower flange 12a of the bridge girder 12 in the actual viaduct, the ambient temperature 600 mm above each test body, and the upper side of each test body The upper surface temperature of the frame 3 was measured using a thermocouple. The results are shown in Table 2.

The following (1) to (4) were found from the results of the fire resistance experiment.
(1) Although thermal deformation was observed in all six types of test specimens (see “Test specimen deformation amount” in Table 2), the cross-sectional shape as a structure could be maintained.

(2) As the thickness of the heat insulating material 5 increases (the more the amount), the temperature rise of the upper surface of the test body (the upper surface of the upper frame 3) is suppressed, and the temperature of the upper surface of the test body is a ceramic fiber blanket 1 having a thickness of 25 mm. It could be suppressed to about 350 ° C. above the layer.

(3) As shown in Table 2, the temperature of the transverse beam 16 ′ supporting the test body is about 120 ° C., and the test is performed assuming the position of the lower flange 12a of the bridge girder 12 in the viaduct to be maintained. The atmospheric temperature above 600 mm of the body was limited to about 60 ° C. to 80 ° C. in the six types of test bodies, and could be suppressed to a temperature range in which the strength of the steel material (bridge girder) constituting the superstructure of the high bridge was not reduced.

(4) As shown in Table 2, although the amount of deformation of the comparative type A1 and A2 specimens without the heat insulating material 5 is the smallest, the heat receiving temperature (the temperature of the upper surface of the upper frame) is about 500 ° C. Therefore, there is a concern that the strength of the upper frame 3 is reduced. On the other hand, in the type B1 and B2 test body of the example provided with the heat insulating material 5 and the type C1 and C2 test body of the comparative example, the deformation amount increased as the thickness of the heat insulating material 5 increased. This is considered to be because the temperature difference between the upper and lower surfaces of the upper frame 3 is increased by the heat insulating material 5. From this, the Example of type B1 which has arrange | positioned the heat insulating material 5 to the lower part of the upper side frame 3 is considered to be more preferable.

DESCRIPTION OF SYMBOLS 1 ... Viaduct backside fireproof sound absorption structure 2 ... Lower frame 3 ... Upper frame 3a ... Thermal insulation support part 4 ... Sound absorption material 5 ... Thermal insulation 6 ... Thermal insulation material for upper frame protection 7 ... Ceramic sheet 8 ... Bolt 10 ... Viaduct 11 ... Floor slab 12 ... Bridge girder (main girder) 12a ... Bottom flange of bridge girder 13 ... Tilt structure 14 ... Horizontal member 15 ... Suspension member 16, 16 '... Cross beam

Claims (3)

  A plurality of bridges connected to and suspended from under the viaduct bridge girder, and are installed on the backside of the viaduct so that it surrounds the entire backside of the viaduct. A frame is formed with the lower frame in the form of a channel opened on the lower side, an upper frame having a heat insulating material supporting portion extending inward at the lower part, and a flat plate disposed in the lower frame A sound absorbing material having a shape and supported by the heat insulating material support portion in the upper frame body, having a heat resistance of 1100 ° C. or more, having a flat plate shape, and protecting the viaduct from fire heat due to a fire under the viaduct And a heat-absorbing sound-absorbing material for the backside of the bridge, comprising: a heat-insulating material for heat treatment, and a heat-resistant material for protecting the upper frame body from fire heat. Structure.   The upper frame body protection heat insulating material has a flat plate shape, and is disposed in the lower frame body so as to cover the entire lower side of the upper frame body including the heat insulating material support portion. The via-bridge backside fireproof sound absorbing structure according to claim 1.   3. The viaduct backside soundproof structure according to claim 1, wherein the heat insulating material and the heat insulating material for protecting the upper frame body are made of a ceramic fiber blanket.

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