JP5317340B2 - Fire protection structure for bridges - Google Patents

Description

  The present invention relates to a fire protection structure for a bridge such as a viaduct. More particularly, the present invention relates to a fire protection structure for preventing a bridge from being deteriorated or damaged by a vehicle fire or the like.

  Conventionally, bridges such as overpasses, overpasses or viaducts have been provided for the purpose of, for example, three-dimensional intersections of roads and railways. Especially in urban areas, overpasses and overpasses are installed on high-traffic roads and tracks, and viaducts such as expressways are installed on ordinary roads in parallel with long sections, and the viaducts are configured in multiple upper and lower stages. As the traffic volume increases, the bridge structure tends to become more complex.

  In addition, bridges such as those described above are generally provided with a floor slab made of concrete or the like on the bridge girder or bridge girder, and traffic accidents etc. occur under the floor slab or pier. When a vehicle such as an automobile burns, the bridge may be deteriorated or deteriorated by heat generated at that time, a flammable product, or the like. In particular, concrete floor slabs have problems such as deterioration of durability due to deterioration of cement-based materials in concrete due to heat.

  Therefore, as a fire countermeasure for the bridge as described above, a liquid refractory material is applied or sprayed on the lower surface of the bridge girder, floor slab, etc., or a precast refractory material previously molded into a predetermined shape is used for the bridge girder, floor slab, etc. However, it is not preferable from the viewpoint of maintenance of the bridge structure to cover with a refractory material as described above. In other words, the bridges described above are not only exposed to dangers such as vehicle fires, but especially in concrete floor slabs, factors that cause deterioration of concrete gradually due to automobile exhaust gas, traffic vibration, etc. It is necessary to constantly monitor and manage the frame so that concrete peeling at the bottom of the slab does not occur, but if the bridge girder, floor slab, etc. are covered with a refractory material as described above, This is because there is a risk of hindering monitoring and management.

  In Patent Documents 1 to 3 below, a panel cover and a shielding plate are laid so as to cover the lower and side surfaces of the bridge girder for the purpose of preventing the corrosion of the bridge, particularly the corrosion due to the flying salt in the coastal area. It has been proposed. However, each of the above documents 1 to 3 prevents the bridge girder from touching the outside air by covering the lower surface and both side surfaces of the bridge girder provided below the floor slab with a panel cover or a shielding plate without any gaps. Even if it is possible to prevent the bridge from being corroded by the above, it is not possible to prevent the deterioration and deterioration of the bridge due to the fire as described above. In particular, when fuel such as gasoline is ignited in a car accident or when flammable oils in a tank lorry load are ignited, the thermal power is strong and the slab and bridge girder are deformed or damaged by exceeding the heat resistance temperature of the bridge. There are many cases. Repairing it takes a lot of time and effort, and during that time, the bridge becomes inaccessible, so there are inconveniences such as inconvenience, inconvenience and loss in terms of convenience of transportation and economy. .

JP 2004-324230 A JP 2007-154572 A JP 2007-154576 A

  The present invention has been proposed in view of the above-mentioned problems, and bridges such as viaducts, in particular, bridges that can prevent deterioration and damage due to vehicle fires and the like as much as possible without hindering maintenance of floor slabs and bridge girders. The purpose is to provide a fire protection structure.

In order to achieve the above object, the bridge fire protection structure according to the present invention has the following configuration. That is, it is a fire protection structure of a bridge in which a floor slab is placed and fixed on a bridge girder bridged on adjacent abutments, and a plurality of sheets are connected to the lower part of the bridge girder via a field guard and a panel support frame . A flame shield panel is hung and attached so as to cover the lower surface of the floor slab and the lower surface of the bridge girder, and among the plurality of flame shield panels, the flame shield panel located on both sides in the width direction of the floor slab A rising portion that covers the lower outer surface of the bridge girder located on both sides in the width direction is provided, and an upper end portion of the rising portion is spaced downward from the floor slab .

  As described above, the fire protection structure of the bridge according to the present invention is attached to the lower part of the bridge girder on which the floor slab is placed and fixed so as to cover the lower surface of the floor slab and the lower surface of the bridge girder. In the unlikely event that a fire breaks out due to a car accident, etc. under the bridge girder, the flame and heat are prevented from being blocked by the above-mentioned flame shield panel and directly acting on the bridge girder and floor slab. Can prevent deterioration or damage. Therefore, for example, there is no hassle such as applying fireproofing treatment to both the bridge girder and the floor slab, and also during construction, it is not necessary to perform troublesome work such as spraying refractory material upward on the underside of the bridge girder or floor slab. There are advantages. Furthermore, because the above-mentioned flame shield panel can be used in a factory, etc., so-called precast, which is formed in a predetermined size and shape, it can be installed in a good working environment without scattering of refractory materials or dust when installed on site. can do.

  In addition, since the flame shield panel is mounted so as to be suspended from the lower part of the bridge, a maintenance space can be formed between the flame shield panel and the bottom surface of the floor slab. Depending on the maintenance space, concrete or the like can be formed. It is possible to easily perform maintenance work for deterioration diagnosis and peeling protection of bridge girders made of floor slabs and I-type steel, etc., and in the event of a fire, the maintenance space becomes a heat insulating space and the temperature of the bridge girders and floor slabs Ascending is suppressed, and deterioration or damage due to flame or heat can be further reduced. Furthermore, since the above-mentioned flame shield panel is attached to the panel support frame attached to the lower part of the bridge girder via a field guard, the structure is simple and can be easily and quickly installed. If it is deteriorated or damaged, it can be easily replaced.

  More preferably, a plurality of the field edge receivers are attached to the lower surface of the bridge girder at a predetermined interval in the longitudinal direction of the bridge girder in a state where the longitudinal direction thereof is arranged substantially perpendicular to the longitudinal direction of the bridge girder, A plurality of panel support frames are mounted in a state where the bridge supports are arranged in the longitudinal direction of the field receiver between adjacent field receivers in the longitudinal direction of the bridge girder, and a plurality of flame shield panels are attached to each panel support frame. Good. With this configuration, a large number of flame shield panels can be attached with a simple structure, and maintenance such as maintenance and replacement of each flame shield panel can be easily performed.

  In addition, the flame shield panel may be attached to the panel support frame via a vibration proof rubber, so that the vibration of an automobile or the like passing over the bridge slab is spread to the flame shield panel. Therefore, the fire protection effect and the durability performance of the flame barrier panel can be improved. Further, as the above-described flame shield panel, for example, a calcium silicate fire-resistant plate main body with a thin metal plate coated on the bridge girder side surface can be used. When such a flame barrier panel is used, the above-mentioned fire protection effect and its durability can be further improved.

The perspective view of the bridge which shows one Embodiment of the fire protection structure by this invention. FIG. 2 is an enlarged longitudinal sectional front view of a part of the bridge of FIG. 1. (A) is an enlarged view of a part of FIG. 2, (b) is a bottom view thereof, FIG. 4A is an enlarged view of a part of FIG. 3A, and FIG. 4A is an enlarged exploded view of a part of FIG. 4A, and FIG. The enlarged view of a part of flameproof panel. AA sectional drawing in Fig.3 (a). FIG. 3 is an exploded perspective view of a field edge receiver, a panel support frame, a flame shield panel, and the like.

  Hereinafter, a fire protection structure for a bridge according to the present invention will be specifically described based on an embodiment shown in the drawings. In the embodiment, the bridge 1 is applied to a viaduct on a highway as shown in FIG. 1, in particular, a viaduct in which a floor slab 2 is provided in two steps, and each floor slab 2 is adjacent to an abutment (bridge pier) 3. It is placed and fixed on the upper surface of a bridge girder (main girder) 4 made of I-shaped steel. The upper surface of each floor slab 2 is paved as a roadway, but is not shown in the figure. In the figure, 2s is a ground cover.

  The bridge girder 4 made of the above I-shaped steel is disposed on the lower surface side of the floor slab 2 so that the longitudinal direction thereof is substantially parallel to the longitudinal direction of the floor slab 2 (front-rear direction in FIG. 2). Are provided in the width direction (left and right direction in FIG. 2). The plurality of bridge girders 4 has a configuration in which the lower flange portion 4b is placed on the upper surface of the abutment 3 and the floor slabs 2b are placed on the upper surface of the upper flange portion 4a.

  And this invention arrange | positions the flame-shielding panel 5 below the bridge girder 4 arrange | positioned at the lower surface side of each said floor slab 2 with predetermined spacing S between the lower surfaces of each floor slab 2, In the form, a plurality of flame shield panels 5 having a predetermined size and shape (in the figure, a rectangular plate having a length and width of about 980 mm) are arranged side by side in the front and rear and left and right directions in FIG. Are attached to the lower part of a plurality of bridge girders 4 through a field edge receiver 6 and a panel support frame 7 attached thereto.

  In the present embodiment, the field edge receiver 6 is formed by cutting the H-shaped steel into a predetermined length as shown in FIGS. 1 to 6 and adding it with appropriate connecting members as necessary. It is formed to have a length substantially the same as the dimension in the width direction of the plate 2, and the edge receiver 6 is attached to the lower flange portions 4 b of the plurality of bridge girders 4 provided on the lower surface side of each floor slab 2. It is attached with metal fittings, bolts and nuts.

  In this embodiment, the panel support frame 7 is fixed to the vertical members 71 and 71 made of a pair of angle members passed between the pair of field receivers 6 and 6, and the vertical members 71 and 71 by welding or the like. The panel supporting frame 7 is composed of bolts 7a and nuts 7b at both ends of each vertical member 71 as shown in FIGS. 4 and 5. As shown in FIG. 5, a large number of bolts 6a and nuts 6b are attached to the pair of edge receivers 6 and 6 through the bracket 73 made of an angle member attached in the above.

  The above-described flameproof panel 5 is attached to each panel support frame 7. In this embodiment, as shown in FIGS. 4 and 8, three flameproof panels 5 are provided on each panel support frame 7. Installed. In particular, in the case of the figure, the four corners of each flame shield panel 5 are the vertical members 71, the central portion of each flame shield panel 5 is the transverse member 72, and a non-screw circumference for preventing falling off as shown in FIG. The bolt 5a having the groove 5a1 and the nut 5b are attached, and the vibration isolating rubber 8 inserted through the bolt 5a is interposed between the vertical member 71 or the horizontal member 72 and the flame shield panel 5.

  The material and thickness of the flame shield panel 5 are appropriate, but in this embodiment, as shown in FIG. 6, the upper surface of a calcium silicate fireproof plate main body 50 manufactured by a 27 mm thick press molding method ( A surface in which a metal thin plate 51 made of a stainless steel plate having a thickness of 1.5 mm is coated on the surface opposite to the panel support frame 7 is used.

  The procedure for constructing the fire protection structure for a bridge according to the present invention configured as described above is appropriate. For example, the construction may be performed in the following manner. First, the field receiver 6 is cut to a predetermined length, or is appropriately added to form a predetermined length, and the field receiver 6 is formed in a state in which the longitudinal direction thereof is oriented in a direction perpendicular to the longitudinal direction of the bridge girder 4. Attach to the lower flange 4b of the bridge girder 4 with mounting brackets, bolts and nuts (not shown).

  Next, the panel support frame 7 composed of the vertical members 71, the cross members 72 and the brackets 73 is attached to the lower surface side of the field edge receiver 6 with bolts 6a and nuts 6b in a state in which they are arranged in the longitudinal direction of the field edge receiver 6, The flame shield panel 5 may be attached to the lower surface side of each panel support frame 7 with bolts 5a and nuts 5b. In addition, after attaching the flame-shielding panel 5 to each said panel support frame 7 previously, each panel support frame 7 may be attached to the field edge receptacle 6, or each panel support frame 7 and flame insulation are attached to the field edge receptacle 6. The panel edge 5 may be attached to the pier 4 after the panel 5 is attached in advance.

  As described above, in the fire protection structure for a bridge according to the present invention, the flame shield panel 5 is provided below the bridge girder 4 so as to cover the lower surface side of the bridge girder 4. Both of the lower surfaces are covered. Therefore, in the unlikely event that a fire occurs due to a car accident or the like below the bridge girder 4, the flame or heat is not blocked by the flame shield panel 5 and directly acts on the bridge girder 4 or floor slab 2. It is possible to satisfactorily prevent the bridge girder 4 and the floor slab 2 from being deteriorated or damaged by flame or heat.

  Further, since the flame shield panel 5 is attached to the lower surface of the bridge 4 with a predetermined space S between the flame shield panel 5 and the lower surface of the floor slab 2, the flame shield panel 5 and the lower surface of the floor slab 2 are interposed between them. A maintenance space S can be formed, and the maintenance space S facilitates maintenance work for diagnosing deterioration of the floor slab 2 made of concrete and the bridge girder 4 made of I-type steel and for protecting against peeling. In addition, it is possible to further reduce the deterioration or damage of the bridge girder 4 and the floor slab 2 due to a flame or heat, because the maintenance space S becomes a heat insulating space.

  Furthermore, since the fireproof performance of both the bridge girder 4 and the floor slab 2 can be improved by the above-mentioned flame shield panel 5, for example, both the bridge girder 4 and the floor slab 2 are not troublesome to perform a fireproofing process, and also during construction. In addition, it is not necessary to perform an awkward work such as spraying a refractory material upward on the lower surface of the bridge girder 4 or floor slab 2, and for example, the flame shield panel 5 is formed in a predetermined size and shape in advance in a factory, Since a so-called precast product can be used, there is an effect that a fireproof material, dust and the like are not scattered at the time of mounting, and the work can be performed in a good working environment.

  In addition, the lower outer surface of the bridge girder 4 located on both sides in the width direction (left and right direction in FIG. 2) of the floor slab 2 as shown in the embodiment of the figure also rises the flame shield panel 5 as shown in FIGS. If it covers by the part 5s, it can prevent that a flame wraps around the bridge girder 4 side from the width direction both ends of the flame-shielding panel 5. FIG. 2 and 3, 6s is a rising portion of the field receiver 6 that supports the rising portion 5s of the flame shield panel 5, and 6t is a stay that supports the rising portion 6s.

  Further, if the flame shield panel 5 is attached to the lower side of the bridge girder 4 via a field edge receiver 6 or a panel support frame 7 or the like, for example, between adjacent field edge receivers 6 and 6 or the field edge receiver 6 and the panel support. A gap or space can be formed between the frame 7 and the upper end of the rising portion 5s below the floor slab 2. If a fire occurs on the lower side of the shading panel 5, Even when the air between the slab and the floor slab 2 is heated through the flame barrier panel 5, the heated air is discharged to the outside through the gap between the rising portion 5s and the floor slab 2. It becomes possible to suppress the temperature rise of the floor slab 2 and the bridge girder 4.

  As described above, the fire protection structure for a bridge according to the present invention is constructed such that the flame shield panel 5 is suspended below the bridge girder 4 so as to cover the lower surface side of the bridge girder 4. In the unlikely event that a fire occurs due to a car accident or the like below the bridge girder 4, the flame or heat is prevented from directly acting on the bridge girder 4 or the floor slab 2. It is possible to satisfactorily prevent deterioration or damage due to heat. Therefore, it is possible to prevent deterioration / damage / disconnection of bridges due to fire, which has become a problem in recent years, especially deterioration / damage of bridges and bridges such as viaducts in urban areas where ordinary roads and highways are intertwined vertically. And can be used effectively industrially.

1 Bridge 2 Floor slab 2s Ground cover 3 Abutment (pier)
4 Bridge girder (main girder)
4a Upper flange 4b Lower flange 5 Flameproof panel 6 Field edge receiver 7 Panel support frame 8 Antivibration rubber

Claims (4)

A fire protection structure for a bridge in which a floor slab is placed and fixed on a bridge girder bridged over adjacent abutments, and a plurality of flame shields are provided under the bridge girder via a field edge receiver and a panel support frame. A panel is hung and attached so as to cover the lower surface of the floor slab and the lower surface of the bridge girder ,
Of the plurality of the flame shield panels, the flame shield panels located on both sides in the width direction of the floor slab are provided with rising portions covering the lower outer surfaces of the bridge girders located on both sides in the width direction. A fire protection structure for a bridge, characterized in that the upper end of the part is spaced below the floor slab .   A plurality of the above-mentioned field edge receivers are mounted on the lower surface of the bridge girder at a predetermined interval in the longitudinal direction of the bridge girder in a state where the longitudinal direction is substantially orthogonal to the longitudinal direction of the bridge girder, and in the longitudinal direction of the bridge girder 2. The fire protection structure for a bridge according to claim 1, wherein a plurality of said panel support frames are attached in the longitudinal direction of the field edge receivers between adjacent field edge supports, and a plurality of flame shield panels are attached to each panel support frame.   The fire protection structure for a bridge according to claim 2, wherein the flame barrier panel is attached to the panel support frame via a vibration isolating rubber.   The bridge fire protection structure according to any one of claims 1 to 3, wherein the flame barrier panel is formed by coating a thin metal plate on a surface of a bridge spar side of a calcium silicate fireproof plate main body.

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