Emergency temporary bridge and its construction method

Abstract

To provide a temporal bridge that can be erected on an emergency basis to save lives and transport supplies in an event of flooding.SOLUTION: An air beam 20, which has a span longer than a distance of a rising water area 3 between an erection starting point side shore 1 and a reaching side shore 2, and whose inner space 21 serves as a passageway, is manufactured by expansion and deployment at the erection starting point side shore 1. The air beam 20 is supported at one end of a bridge end support body 30 provided at the erection starting point side shore 1 and is turned in substantially horizontal around its turning center via a turn table 31 of the bridge end support body 30 until the other end is located on the reaching side shore 2. The other end of the air beam is supported on an airbag bridge abutment 25. This constructs an air beam bridge 10 between the erection starting point side shore 1 and the reaching side shore 2 as an emergency temporal bridge.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an emergency temporary bridge, and more particularly to an emergency temporary bridge that can be erected in an emergency to be used for saving lives, transporting goods, etc., when flood damage occurs due to a typhoon or the like, and a method for constructing the same. [Background technology]

[0002] Various temporary bridges have been put into practical use to temporarily maintain the function of existing bridges when they are damaged or washed away by wind and flood damage caused by typhoons, etc. These temporary bridges have a relatively long service life and require bridges of a size similar to the specifications and structure of the existing bridges, so they are assembled in yards using separate bridge components or constructed using large cranes.

[0003] In addition to river flooding, when roads are flooded and cut off due to rising water levels caused by typhoons or other factors, there is a need for emergency temporary bridges that can withstand loads large enough to allow people to pass through and transport supplies by hand, for example, for rescue operations and the supply of emergency supplies (Non-Patent Document 1).

[0004] For bridges that need to be erected urgently (referred to as emergency temporary bridges), it is necessary that the bridge components can be transported to the erection site in a nearly completed state, that the temporary bridge can be erected from one side of the bank, taking into account the difficulty of accessing the opposite bank, and that the bases (abutments) that support the ends of the temporary bridge girders can be easily constructed.

[0005] As a bridge component that meets these requirements, Non-Patent Document 1 introduces an example of the development of a truss bridge made of lightweight components such as aluminum and wood. The truss bridge as an emergency temporary bridge disclosed in Non-Patent Document 1 has a scissors structure in which the apexes of X-shaped aluminum alloy components are connected in succession like a pantograph with pin joints, and the truss components assembled in a folded X-shape on the bank on the starting point side can be extended horizontally toward the opposite bank using a hydraulic drive system to erect a temporary bridge of a predetermined or specified length.

[0006] Non-Patent Document 1 also proposes an air bridge in which lightweight air beams are reinforced with cables (Non-Patent Document 2). An air bridge using air beams as girders has a structure in which a thin plate serving as a deck is placed on the air beam, and multiple steel wire cables, anchored at both longitudinal ends of the air beam, are wound in a spiral cross-like pattern along the outer surface of the air beam to reinforce the air beam. The air pressure of the air beam is used to apply tension to the cables, and prestress is introduced into the thin plate serving as the deck, resulting in an ultra-lightweight bridge. Patent Document 1 also discloses an invention for a structure in which cables are wound in a spiral on the outer surface of the air beam, which is used in the air bridge of Non-Patent Document 2. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 3906079 [Non-patent literature]

[0008] [Non-Patent Document 1] Shuichi Ono, "Invited Paper: Emergency Temporary Bridge with a Structure for Rapid Erection," [online], March 2016, Japan Society of Civil Engineers, Journal of Structural Engineering, vol. 62A, [Retrieved November 5, 2020], Internet <URL:https: / / www.jstage.jst.go.jp / article / structcivil / 62A / 0 / 62A_1272 / _article / -char / ja / > [Non-patent document 2] Kei Suzuki, "Ultra-lightweight air beams for disaster recovery," Bridges and Foundations, Kensetsu Tosho Co., Ltd., August 2012, pp. 111-114 Summary of the Invention [Problem to be solved by the invention]

[0009] The scissor-structured emergency temporary bridge disclosed in Non-Patent Document 1 is made up of many relatively heavy plate members forming an X-shape, and the scissor-structured beams that gradually extend until they touch the ground on both banks form a cantilever structure, so it is necessary to prepare a counterweight with sufficient mass on the fulcrum (support) side of the cantilever beam.In addition, the hydraulic drive system equipment for extending the scissor-structured truss members is also large-scale.

[0010] In contrast, in the air bridge using air beams disclosed in Non-Patent Document 2, the only equipment required to extend the air beam structure is a compressed air supply means. However, in this air bridge, in order to ensure that the air beam functions reliably as a girder member of the temporary bridge, it is necessary to constantly manage the tensile tension of the cables wound crosswise around the outer surface of the air beam and the air pressure of the air beam when in service.

[0011] The applicant has proposed an emergency temporary bridge that solves the problems of the conventional technology described above (Patent Application No. 2021-40876). In this emergency temporary bridge, a preliminary temporary girder made of aluminum members is first erected from the starting point of construction, where a lightweight deck slab as a bridge member is prepared, to the opposite bank, and then the lightweight deck slab is laid continuously on top of the preliminary temporary girder. The lightweight deck slabs laid continuously to the opposite bank are then structurally integrated to create a bridge structure that is passable for users.

[0012] Therefore, the emergency temporary bridge mentioned above requires the erection of preliminary temporary girders followed by the laying of the permanent lightweight deck. Although the overall process is designed to be quick, there is a risk that it may not be possible to meet the extremely urgent demand for erecting simple bridge components all the way to the opposite bank in one go.

[0013] Therefore, the object of the present invention is to provide an emergency temporary bridge and a method for constructing the same that solves the problems of the conventional technology described above, and that allows a temporary bridge to be completed to a predetermined bridge length at the starting point of construction in the event of a flood or other disaster, and then erected all the way to the opposite bank in one go, using extremely simple construction procedures and that can be erected quickly and safely. [Means for solving the problem]

[0014] The present invention provides a method for constructing an emergency temporary bridge, which has a span longer than the water area distance between the starting bank and the end bank, Compressed air supplied from the outside causes a plurality of parallel adjacent straight cylindrical air tubes to expand and deploy so as to form a tunnel surrounding the internal space, An air beam, the interior of which will become a passageway, is inflated and deployed at the side of the erection starting point, and the air beam is One end is supported on a bridge end support with a pillar installed on the bank on the side of the erection starting point, and the lower half, located approximately in the center of the length, is suspended obliquely so as to be surrounded by a tension member fixed to the rear end of the bridge end support and suspended via the top of the pillar. The bridge end support is rotated approximately horizontally around the rotation center until the other end is positioned at the arrival side bank. hand The other end is supported on the destination bank, and an emergency temporary bridge made of the air beam is constructed between the erection starting point side and the destination bank.

[0015] It is preferable that the air beam be rotated around the center of rotation of a turntable provided on the bridge end support in accordance with the approximately horizontal rotation of the turntable.

[0017] It is preferable that the other end of the air beam is supported by an abutment made of an air bag inflated by air supplied from the erection starting point side.

[0020] The emergency temporary bridge of the present invention has a span longer than the water area distance between the starting point bank and the end bank, and is expanded by supplied compressed air to form an elongated, approximately cylindrical shape. and next to each other Multiple straight cylindrical air tubes form a tunnel surrounding the internal space. The internal space serves as a passageway. Air beam, One end is supported by a part of the bridge end support with a column installed on the starting point side bank, the center position in the longitudinal direction is suspended by a tension member fixed to the rear end of the bridge end support and hung diagonally across the top of the column to surround the lower half, and the other end is supported by an airbag abutment with a height adjustable installed on the reaching side bank, and constructed between the starting point side bank and the reaching side bank. It is characterized by:

[0022] The aforementioned Airbags The abutment is on the side of the starting point of the erection. shore Expands with air supplied from vinegar It is preferable that

[0023] It is preferable that the air beam is suspended at the midpoint of the span by a tension member extending from the top of a pillar erected on the bridge end support. [Effects of the Invention]

[0024] As described above, the present invention has the effect of enabling the construction and erection of emergency temporary bridges for use in saving lives, transporting supplies, etc., to be carried out quickly and safely when flood damage occurs due to a typhoon or the like. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a perspective view showing the completed erection state of an embodiment of an emergency temporary bridge of the present invention. [Figure 2] A side view of the emergency temporary bridge shown in Figure 1. [Figure 3] Construction sequence diagram ((a) to (f)) showing the procedure for expanding the bridge components (air beams) of the emergency temporary bridge shown in Figure 1 at the starting point of construction. [Figure 4] Construction sequence diagram ((a) to (d)) showing the construction steps for constructing an emergency temporary bridge. [Figure 5] Construction sequence diagram (e)-(g) showing the construction procedure for constructing an emergency temporary bridge. [Figure 6] Construction status diagram showing the erection status of the emergency temporary bridge ((a) and (b)). [Figure 7] 1A and 1B are cross-sectional views showing cross-sectional shapes of a plurality of embodiments of a bridge member (air beam). [Figure 8] FIG. 7(c) is a plan view of an air beam having the cross-sectional shape shown in FIG. [Figure 9] FIG. 10 is a partially enlarged view illustrating an example of the configuration of an airbag abutment and its inflated state. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, the configuration of an emergency temporary bridge according to one embodiment of the present invention and the expansion, deployment, construction and erection of bridge components will be described with reference to the accompanying drawings.

[0027] 1 and 2 show, as an example, a state in which an emergency temporary bridge 10 has been erected from one bank side (construction starting point side) 1 to the other isolated bank (reach side 2) at a location where a road has been cut off, blocked off, and isolated due to flooding caused by a river where an existing bridge has been washed away or flooded by rising waters, spanning a flooded area 3 between the construction starting point side 1 and the reach side 2. This emergency temporary bridge 10 has as its bridge body a tunnel-like, approximately cylindrical air beam structure 20 (hereinafter referred to as air beam 20) suspended at the midpoint of its span by suspension wires W suspended across truss columns 35 erected as part of bridge end supports 30 installed on vehicles 4 parked along the bank at the construction starting point side 1. A victim M on the isolated bank side (reach side 2) can be evacuated to a safe bank side (construction starting point side 1) by moving through the approximately cylindrical internal space 21 of the air beam 20.

[0028] [Air beam bridge configuration] As shown in Figures 1 to 3, the air beam 20, which is the main component of the emergency temporary bridge 10 (hereinafter referred to as the air beam bridge 10 due to its structural characteristics) configured as described above, changes shape during transportation when it is spirally wound up (Figure 3(a)), when it is inflated and unfolded by supplied compressed air into an elongated cylindrical shape (Figure 3(e)), and again when it is erected (Figures 1, 2, and 3(f)). First, the overall shape of the elongated cylindrical air beam 20 upon inflation will be described with reference to Figure 3(e). As shown in Figure 3(e) in cross section and longitudinal section, the air beam 20 is made of an airtight fabric material in which 12 elongated air tubes 22, 22, ... each approximately 300 mm in diameter are connected via an outer skin sheet 23 that covers the outer surface of the final cylindrical shape so that the air tubes 22 are closely adjacent to each other and form a roughly circular ring shape upon inflation. In this embodiment, the outer diameter of the annular air beam 20 after inflation is approximately 1,800 mm, and the diameter of the internal space 21 (inner diameter of the annulus) is approximately 1,200 mm. The length (span) of the air beam 20 is determined based on the distance between the shores to be erected, and in this embodiment, the span is 12 m. The air beam 20 in its initial state before inflation is made of a flat, elongated bag-like body. By winding up the elongated bag-like body into a spiral coil as shown in FIG. 3(a), it can be made into a compact shape that is easy to transport (hereinafter, the spiral state shown in FIG. 3(a) will be referred to as coil body C). Meanwhile, a roughly rectangular parallelepiped-shaped inflated airbag abutment 25 (hereinafter, referred to as airbag abutment 25) is constructed at another support point of the temporary bridge (air beam bridge 10). As shown in Figures 2 and 9, the height of this airbag abutment 25 can be appropriately set by adjusting the inflation amount of the airbag to ensure a stable installation state of the bridge when the air beam bridge 10 is completed.

[0029] The material of the air tube 22 is a resin sheet in the shape of an elongated bag, which is made of a base fabric made of woven polyamide fiber and coated with vinyl chloride resin, and which becomes a cylindrical shape of a predetermined diameter when inflated. Silicone resin, urethane resin, etc. are also suitable as the coating resin.

[0030] Various types of woven fabrics can be used as the material for the outer skin sheet 23, such as polyester (e.g., polyethylene terephthalate: PET) woven fabric, vinyl chloride resin-coated PET woven fabric (e.g., tarpaulin), polypropylene (PP) woven fabric, polyethylene (PE) woven fabric, etc. Note that the outer skin sheet 23 not only serves to prevent ripping and tearing due to external forces when the temporary bridge is installed, but also functions as a tensile resistance material for the air beam bridge 10, which is a member on which a bending moment acts, so it is desirable for the sheet to have high tensile rigidity, with an elongation rate of, for example, 20% or less.

[0031] [Structure of bridge end supports] The structure of the bridge end support 30 will be explained with reference to Figures 1, 2, 4, and 5. The bridge end support 30 is a steel truss structure installed on a vehicle (truck) 4 parked along the bank at the erection starting point 1, and as shown in Figures 1 and 4(a), it is assembled on truck 4 that has been transported to the site carrying air beam 20 (hereinafter referred to as coil body C) in a pre-expanded state wound into a spiral coil and steel material 8 before assembly that will become the truss structure, thereby serving as one of the bridge supports at the erection starting point of the air beam bridge 10. It consists of a base frame 34 assembled in a rectangular planar shape by stiffening two main girders 32 with cross members 33 on a turntable 31 installed on the bed of a truck 4, a tower-shaped truss column 35 formed by assembling four diagonal columns 35a in a truss shape on the base frame 34, an outrigger 36 that supports the load borne by the base frame 34 and truss column 35 on the ground, and a beam base 37 that supports one end of the air beam 20. The turntable 31 is a ready-made flat ring-shaped support member with a built-in bearing that allows smooth in-plane rotation even by hand when the full load acts on the truss column 35 supporting and lifting one end of the air beam 20 in the fully inflated and deployed state, as shown in Figure 5(f). 1 and 2, the platform frame 34 can mount a counterweight 38 on part of the frame, and by adjusting the weight using this counterweight 38, the balance of the turntable 31 can be adjusted during rotation when the load of the air beam 20 is applied while it is suspended. As the counterweight 38, a conventional cast iron weight can be used, or it is preferable to use a water bag (water tank) that can store a predetermined volume of water, and to ensure the predetermined mass by pumping water from the flood area 3 with a pump (not shown) or the like and storing it in the water tank. In this case, there is no need to transport heavy weights or the like to the site, which reduces the burden of transporting equipment and materials.

[0032] As shown in Figures 1 and 2, the truss column 35 is composed of four diagonal columns 35a, each with a base mounted on the main girder of the frame 34, tie beams 35b stiffening the diagonal columns 35a at mid-height, and tie rods 35c installed in an X-shape to maintain the truss shape. Eye nuts 35d are attached to the tops of the columns, through which the suspension wires W are inserted and which fold back in the insertion direction. The ends of the suspension wires W are fixed to eye nuts 32a attached to the rear ends of the main girders 32 of the frame 34. A frame-shaped beam base 37 is provided at the tip of the frame 34 to support the ends of the inflated air beams 20. This beam base 37 functions as one of the support structures of the bridge when the air beams 20 are installed as a temporary bridge (Figure 2). As shown in Figures 1 and 6(a), the outrigger 36 consists of four extending beams 36a that extend perpendicularly in all directions, support legs 36b that support the tips of the extending beams 36a that extend from the bed of the truck 4, and ground plates 36c at the lower ends of the support legs 36b, and the center points of the four extending beams 36a coincide with the center of rotation of the turntable 31.

[0033] [Air beam expansion and deployment work] The procedure for inflating and deploying the air beam 20 will be described with reference to FIGS. 3(a) to 3(f). FIG. 3(a) shows a spirally wound coil body C that will later be inflated and deployed to form the air beam 20. This coil body C is provided with air inlets 11 and 12 for multiple compressed air supply hoses 7. The air inlet 11 is provided on the end face of the air tube 22L, which is located at the bottom of the multiple air tubes 22, 22, ... when inflated and deployed, and the compressed air supply hose 7 extending from the blower 6 is connected to the air inlet 11 in the initial stage of the inflating and deploying operation of the air beam 20. Then, as shown in FIG. 3(b), compressed air is first supplied to the air inlet 11 of the lower air tube 22L, which is the outermost part of the coil body C. This causes the lower air tube 22L to inflate and extend from its end, and the coil body C rotates in the direction of the arrow and unrolls, ultimately forming the slightly thick, flat, mat-like air beam 20 (FIG. 3(c)). From this stage, compressed air is continuously supplied from the air inlet 12 connected to the compressed air supply hose 7 to the other air tubes 22 of the air beam 20, which are connected in a circular cross section, gradually expanding the entire air beam 20 (Fig. 3(d)), and eventually each air tube 22 takes on the elongated cylindrical shape shown in Fig. 3(e), forming the air beam 20 with an internal space 21 surrounded by each air tube 22, and the air beam 20 reaches a fully expanded state. The air inlet 11, 12 can be provided on the inner or outer surface of the installation starting point 1 of the air beam 20, or on the side of each air tube 22, and it is preferable to set the number of such inlets as appropriate according to the inflation and deployment pattern.

[0034] [Configuration and construction of airbag abutments] Figure 3(f) shows the state in which the airbag abutment 25, which will serve as the abutment on the destination side 2 (opposite bank), has been inflated and constructed after the air beam 20 has been erected from the erection starting point side 1 to the destination side 2. This airbag abutment 25 is constructed by inflating an airbag 26, which has a roughly rectangular parallelepiped inflated shape and was attached in a folded state to the underside of the tip of the air beam 20 in advance. In order to inflate only the airbag 26 after erection, an air supply hose 27 is stored in advance inside the lowest air tube 22L. When the tip side of the air beam 20, inflated and deployed as shown in Figure 3(e), reaches the opposite bank (destination side 2), compressed air is supplied to the airbag 26 via the air supply hose 27, thereby constructing the roughly rectangular parallelepiped airbag abutment 25 with a predetermined abutment height. In each of the figures in Figure 3, an example is shown in which the airbag abutment 25 uses an airbag 26 consisting of a single bag-shaped body, but the configuration of the airbag abutment 25 using an airbag 26 consisting of a bag-shaped body with a multi-layer structure will be described later with reference to each of the figures in Figure 9.

[0035] [Air beam bridge construction work] The construction procedure and erection work of the air beam bridge 10 will be explained below with reference to FIGS. Figure 4(a) shows the state in which the coil body C is loaded onto the bed of a truck 4 and transported to the shore on the side that will become one of the support structures of the air beam bridge 10 (the erection starting point side 1). The same figure also shows multiple steel members 8 that have already been transported and will be assembled to the trestle frame 34 and truss columns 35 of the bridge end support 30. As shown in Figure 4(b), the work of inflating and deploying the coil body C of the unloaded air beam 20 and the work of constructing the bridge end support 30 on the bed of the truck 4 are carried out in parallel. To inflate and deploy the coil body C, a compressed air supply hose 7 from a blower 6 is connected to the rear end of the air beam 20, and the deployment of the air beam 20 proceeds by inflating the air tube 22L at the lower level of the air beam 20. Meanwhile, a turntable 31 is installed on the bed of the truck 4, and the trestle frame 34 is being assembled on this turntable 31.

[0036] 4(c) shows the state in which the lower end of one of the truss columns 35 assembled on the ground is set into a column base anchor plate (not shown) of the mounting frame 34 installed on the bed of the truck 4, the truss column 35 is rotated around one of its column base parts as a fulcrum to stand up, and each column base part of the truss column 35 is fixed to a column base anchor plate (not shown) provided on the mounting frame 34, thereby constructing the truss column 35 on the mounting frame 34. After this work, a beam pedestal 37 is attached to the tip side of the mounting frame 34.

[0037] FIG. 4(d) shows the state immediately before the fully inflated air beam 20 is loaded onto the platform frame 34 on the bed of the truck 4. From this state, as shown in FIGS. 1, 5(e), and 5(f), the lifting wire W, which is fixed to the eye nut 32a at the rear end of the main girder 32 of the platform frame 34 and suspended in an inverted V shape via the eye nut 35d at the top of the truss column 35, is suspended diagonally across the lower half of the air beam 20 at approximately the center in the longitudinal direction. The lifting wire W is then wound with an on-board winch 39, pulling and lifting the rear end 20a of the air beam 20, and the rear end 20a is placed on the beam base 37 (FIG. 5(e)). With the end of the air beam 20 placed on the beam base, the lifting wire W is wound up to hold the air beam 20 horizontally (FIG. 5(f)). At this time, a counterweight 38 is loaded on the rear end of the frame 34 to adjust the center of gravity when the air beam 20 is lifted, maintaining the horizontal balance of the air beam 20. A band-shaped protective belt 28 is attached to the area of ​​the hoisting wire W that comes into contact with the outer sheet 23 of the air beam 20, protecting the outer sheet 23 of the air beam 20 from being damaged by friction with the hoisting wire W. It is also preferable to install a tensioner T near the fixed end of the hoisting wire W to adjust the length of the hoisting wire W and control the holding state of the air beam 20.

[0038] [Air beam rotation] The rotation of the air beam 20, a main component of the air beam bridge 10, will be explained with reference to Figures 6(a) and 6(b). Figures 6(a) and 6(b) are construction explanatory diagrams showing the same state of the air beam bridge 10 as shown in Figures 5(f) and 5(g), but in a schematic plan view so that the blocked flooded area 3 and both banks 1 and 2 can be seen. At the stage shown in Figure 6(a), the airbag abutment 25 has not yet been constructed. The air beam 20, which is held horizontally by the bridge end support 30 at the starting point of construction 1 (Figure 6(a)), is rotated by rotating the turntable 31 of the bridge end support 30 while maintaining this horizontal state, as shown in Figure 6(b), so that the tip of the air beam 20 is rotated approximately 90° around the bridge end support 30 until it is positioned on the opposite bank 2 of the flooded area 3, thereby erecting the bridge so that it spans the flooded area 3. The turning operation using the turntable 31 can be performed using a powered machine (not shown) such as a small winch, or manually. When the tip of the air beam 20 reaches a predetermined position on the opposite bank 2, the air bags 26 attached in a folded state to the tip of the air beam 20 are inflated using a blower 6 (Fig. 3(f)) installed on the bridge end support 30 side, and the air bag abutments 25 are constructed, thereby achieving horizontal stability of the air beam bridge 10 and completing the erection work of the air beam bridge 10. After that, safety equipment such as steps and handrails (not shown) are installed to allow passage through the internal space 21 of the air beam 20, making it possible to pass through as a temporary bridge (Figs. 1 and 5(g)).

[0039] Each figure in FIG. 7 is a cross-sectional view showing the cross-sectional shapes of air beams having various shapes. FIG. 7(a) shows the cross-sectional shape of an air beam 20 having a substantially circular ring shape in the embodiment described in this specification. The air beam 20 having this cross-sectional shape has an extremely stable structure because the air tubes 22 are arranged in a circular ring shape and inflated. However, the curved floor surface 21a makes the footing of pedestrians unstable when passing through the internal space 21. Therefore, as shown in FIG. 7(b), it is preferable to arrange the air tubes 22L on the bottom surface horizontally so that the internal space 21 has a substantially semicircular shape. Furthermore, it is also preferable to enhance the stability of the floor surface by laying a relatively rigid resin sheet (not shown) or the like on the upper surface of the air tubes 22L, which forms the floor surface 21a.

[0040] It is also preferable to use a relatively smooth material with a friction coefficient of 0.5 or less for the membrane material (sheet) on the inner surface of the tunnel-shaped air beam 20. Alternatively, it is possible to apply paint with a similar friction coefficient to the membrane surface after application, or to attach or lay a resin sheet with a similar friction coefficient. This allows for smooth transport of materials and supplies within the tunnel, as well as the passage of evacuees and stretchers.

[0041] FIG. 7(c) shows an example of an air beam 20 with an open upper section, formed by connecting air tubes 22 in a roughly U-shape. This air beam 20 has the advantage of ensuring a large floor area for traffic. However, if a load is applied to the air tube 22L, which forms the floor, causing cross-sectional deformation, the air tube 22S, which corresponds to the side wall, may deform and tilt inward. To prevent this deformation, as shown in FIG. 8, it is preferable to arrange multiple strut members 29 along the longitudinal direction of the air beam 20 so that they span between opposing air tubes 22S. These strut members 29 can be made with a simple structure, such as a structure in which the ends are supported by pocket-shaped brackets (not shown) previously formed on the side of the air tube 22.

[0042] 9(a)-9(c) are explanatory diagrams illustrating an example of an airbag abutment 25 constructed using airbags 26 made of multilayered bag-shaped structures, as opposed to the airbags 26 shown in each of the figures in FIG. 3. The airbag 26 shown in FIG. 9(a) is an airbag 26 that, upon inflation, is folded and consists of three airbags 26a, 26b, and 26c, each of which has a thinner inflated thickness (height) than the airbag 25 shown in FIG. 3(f). Each airbag 26a, 26b, and 26c is connected to an air supply hose 27 that can supply air independently. This allows compressed air to be supplied independently to each layer of airbag. For example, as shown in FIGS. 9(b) and 9(c), if there is a difference in ground elevation between the bank on the arrival side 2 and the starting point side 1 (not shown), the air beam bridge 10 can be installed horizontally and stably by inflating only the airbags 26a, 26b, and 26c that can achieve the required installation height. It is also possible to give the air beam 20 a slight difference in elevation (gradient) to create a gently sloping air beam bridge 10. With such an air beam bridge 10, it is also possible to efficiently move a sled-like stretcher carrying an injured person from the stricken shore side (reach side 2) by sliding it within the internal space 21 of the air beam bridge 10.

[0043] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. In other words, embodiments obtained by combining technical means modified appropriately within the scope of the claims are also included in the technical scope of the present invention. [Explanation of symbols]

[0044] 1 Erection starting point side (shore) 2 Arrival side (shore) 4 Vehicles (trucks) 6 Blower 7 Compressed air supply hose 10 Emergency temporary bridge (air beam bridge) 20 Air Beam 21 Interior Space 22 Air tube 25 Airbag Abutment 26 Airbag 28 Protective Belt 30 Bridge end support 31 Turntable 34 Mounting frame 35 Truss column 36 Outrigger 37 Beam base 38 Counterweight W Hanging wire C Coil body

Claims

1. The air beam has a span longer than the water area distance between the construction starting point side bank and the arrival side bank, and is inflated and deployed by compressed air supplied from the outside, with a plurality of parallel adjacent right cylindrical air tubes that are inflated and deployed to form a tunnel-like shape surrounding an internal space, with the internal space serving as a passageway, on the construction starting point side bank, The air beam, One end is supported on a bridge end support with a pillar installed on the bank on the side of the erection starting point, and the lower half, located approximately in the center of the length, is suspended obliquely so as to be surrounded by a tension member fixed to the rear end of the bridge end support and suspended via the top of the pillar. The bridge end support is rotated approximately horizontally around the rotation center until the other end is positioned on the arrival side bank, and the other end is supported on the arrival side bank; A method for constructing an emergency temporary bridge, comprising constructing an emergency temporary bridge made of the air beams between the starting point side and the destination side bank.

2. 2. A method for constructing an emergency temporary bridge according to claim 1, wherein the air beam rotates around the center of rotation of a turntable provided on the bridge end support in accordance with the approximately horizontal rotation of the turntable.

3. 2. A method for constructing an emergency temporary bridge according to claim 1, wherein the other end of the air beam is supported by an abutment made of an air bag inflated by air supplied from the bank on the side of the starting point of erection.

4. An air beam has a span longer than the distance between the water area between the starting point side bank and the end point side bank, and is expanded by supplied compressed air to form an elongated, approximately cylindrical shape, and is made up of a plurality of right cylindrical air tubes arranged side by side to form a tunnel-like shape surrounding an internal space, and the internal space serves as a passageway. One end is supported by a part of the bridge end support having a pillar provided on the side bank of the erection starting point, The center position in the longitudinal direction is suspended by a tension member fixed to the rear end of the bridge end support and hung diagonally across the top of the column to surround the lower half, The other end is supported by a height-adjustable airbag abutment provided on the arrival side bank, An emergency temporary bridge constructed between the starting bank and the arrival bank.

5. 5. The emergency temporary bridge according to claim 4, wherein the airbag abutment is inflated by air supplied from the bank on the side of the starting point of erection.

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