Bridge construction method and the bridge

Abstract

To provide a construction method for a bridge which can be easily constructed with a simple structure in places such as remote mountainous areas or valleys with undeveloped roads where it is difficult to prepare large heavy equipment and there are no engineers, and to provide such a bridge.SOLUTION: The present invention relates to a method for constructing a bridge having a bridge length of 10 m to 30 m, which is constructed between slope faces or embankments provided on slopes facing each other across a stream or valley in the mountains, or between banks sandwiching a well-maintained river. The method includes the steps for: installing a bridge girder formed by arranging two steel pipes having a substantially circular cross-section in parallel in a bridging direction in a bridging area; installing a plurality of horizontal girders joined to the two steel pipes at a fixed interval substantially perpendicular to each of the two steel pipes; placing a floor slab on an installed bridge girder; and extending a handrail to each of the two steel pipes or erecting a handrail on the floor slab. The present invention also relates to a bridge constructed by the method.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for constructing a bridge using circular steel pipes and to the bridge itself.

Background Art

[0002] In recent years, large-scale natural disasters such as earthquakes, typhoons, heavy rains, and landslides have occurred frequently worldwide. At such times, many temporary bridges are needed as emergency alternative bridges or as a means in the initial stage of the restoration work from such disasters. Many proposals have been made regarding the structure and construction method of such temporary bridges. In these temporary bridges, the main girder placed on the bridge piers is assembled by connecting a plurality of steel materials in the longitudinal direction, and a deck slab is installed on the main girder to assemble the superstructure of the bridge piers.

[0003] The invention described in Patent Document 1 proposes a method for easily assembling the above-described main girder and a bridge using the main girder.

[0004] However, this construction method involves lifting and installing steel pipes with a crane, and it is premised on building a bridge at a location where crane operation preparation is possible. It is not intended for a bridge that can be easily constructed with a simple structure in mountainous and remote areas, valleys, unimproved roads, etc., where it is difficult to prepare large heavy machinery and there are no engineers.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention was made to solve the conventional problems described above, and aims to provide a bridge construction method and such a bridge that can be easily constructed with a simple structure in mountainous and remote areas, valleys, and places where roads are not developed and engineers are unavailable, where it is difficult to prepare large heavy machinery. More specifically, it aims to provide a bridge construction method and such a bridge that can be easily erected in a short period of time, while ensuring safety and durability. [Means for solving the problem]

[0007] The invention according to claim 1 is a method for constructing a bridge with a length of 10m to 30m, which is erected between slopes or embankments on opposite sides of a mountain stream or valley, or between banks of a well-maintained river. (1) A step of installing a bridge girder in the bridge area where the bridge is to be constructed, which consists of two steel pipes with a substantially circular cross-section arranged parallel to each other in the direction of the bridge construction, (2) A step of installing a plurality of crossbeams joined to the two steel pipes, which are arranged parallel to each other in step (1), at approximately right angles to each of the two steel pipes, at regular intervals, (3) A step of placing a deck slab on the bridge girder installed in step (1) above, (4) The step of extending a railing to each of the two steel pipes, or erecting a railing on the floor slab obtained in step (3), is not included. the law of nature, The steel materials constituting the bridge girder are painted to prevent corrosion due to wind and rain, and the transverse girders and the deck slab are adjusted to allow for on-site joining. The steel material constituting the crossbeam is selected from the group consisting of C-shaped steel, channel steel, and flat steel, and is painted to prevent corrosion due to wind and rain, and is adjusted to be joined to the two steel pipes in the field. The aforementioned deck slab is composed of one or more materials selected from the group consisting of wood, metal, concrete, carbon, synthetic resin, fiber, ceramic, concrete, glass, and stone, and is configured to have a bending moment that allows vehicles to pass over it, and is adjusted to be joined in place with the two circular steel pipes. The railing is constructed by arranging multiple posts in a row to prevent pedestrians from falling. The present invention relates to a bridge construction method characterized by the following:

[0008] The invention according to claim 2 is a method for constructing a bridge with a length of 10m to 30m, which is erected between slopes or embankments on opposite sides of a mountain stream or valley, or between banks of a well-maintained river. (1) A process of manufacturing a module at a first location, comprising a bridge girder formed by arranging two steel pipes with a roughly circular cross-section in parallel, and a plurality of transverse girders configured to connect the two steel pipes at regular intervals, at roughly right angles to each of the two steel pipes, (2) A step of transporting the module together with the deck, railings and deck installation components and railing installation components to the bridge area where the bridge will be constructed, by waterway or land route, (3) The process of erecting the module at a predetermined location in the bridge area (4) A step of placing a floor slab on the module and joining the floor slab to the module using floor slab installation components, (5) The process of placing the railing on the floor slab joined to the module in step (4) and joining the railing to the module using railing installation parts, is not included. the law of nature, The steel materials constituting the bridge girder are painted to prevent corrosion due to wind and rain, and the transverse girders and the deck slab are adjusted to allow for on-site joining. The steel material constituting the crossbeam is selected from the group consisting of C-shaped steel, channel steel, and flat steel, and is painted to prevent corrosion due to wind and rain, and is adjusted to be joined to the two steel pipes in the field. The aforementioned deck slab is composed of one or more materials selected from the group consisting of wood, metal, concrete, carbon, synthetic resin, fiber, ceramic, concrete, glass, and stone, and is configured to have a bending moment that allows vehicles to pass over it, and is adjusted to be joined in place with the two circular steel pipes. The railing is constructed by arranging multiple posts in a row to prevent pedestrians from falling. The present invention relates to a bridge construction method characterized by the following:

[0009] The invention according to claim 3 is characterized in that step (1) incorporates step (4), the floor slab is placed on the module, and floor slab Module 2 is manufactured by joining the above module, In step (2) above, the module 2 is transported to the bridge area together with the railing and railing installation components. In step (3) above, the module 2 is erected at a predetermined location in the bridge area, The present invention relates to the bridge construction method according to claim 2, wherein in step (5) above, a railing is placed on the module 2 and the railing is joined to the module 2 using railing installation components.

[0010] The invention according to claim 4 relates to the preceding step (1) writing The section (5) is incorporated, the railing is placed on the module 2, and the railing is joined to the module 2 to manufacture the bridge body. In the step (2), the bridge body is transported to the bridging area, In the step (3), the bridge body is installed at a predetermined location in the bridging area, according to claim 3 relates to the method for constructing a bridge described in.

[0011] The invention according to claim 5 is a method for constructing a bridge with a bridge length of 10 m to 30 m, which is installed between slopes facing each other across a mountain stream or valley, or a retaining wall or embankment provided on a slope, or between embankments sandwiching a developed river, (1) A step of manufacturing a module composed of a bridge girder formed by arranging two steel pipes with a substantially circular cross-section in parallel, and a plurality of cross girders configured to connect the two steel pipes at regular intervals at substantially right angles to each of the two steel pipes, wherein each of the two steel pipes is provided with an arm for connecting a railing, the step of manufacturing a module; (2) A step of transporting the module to the bridging area where the bridge is to be spanned, together with a floor slab, a railing, parts for installing the floor slab, and parts for installing the railing, by waterway or land; (3) A step of installing the module at a predetermined location in the bridging area; (4) A step of placing a floor slab on the module and joining the floor slab to the module using parts for installing the floor slab; (5) A step of connecting and joining a railing to an arm for connecting a railing provided on the two steel pipes, the law of nature 、 The steel materials constituting the bridge girder are painted to prevent corrosion due to wind and rain, and the transverse girders and the deck slab are adjusted to allow for on-site joining. The steel material constituting the crossbeam is selected from the group consisting of C-shaped steel, channel steel, and flat steel, and is painted to prevent corrosion due to wind and rain, and is adjusted to be joined to the two steel pipes in the field. The aforementioned deck slab is composed of one or more materials selected from the group consisting of wood, metal, concrete, carbon, synthetic resin, fiber, ceramic, concrete, glass, and stone, and is configured to have a bending moment that allows vehicles to pass over it, and is adjusted to be joined in place with the two circular steel pipes. The railing is constructed by arranging multiple posts in a row to prevent pedestrians from falling. characterized in that it relates to a method for constructing a bridge.

[0012] The invention according to claim 6 incorporates the step (4) in the step (1), places the floor slab on the module, and joins the floor slab to the module to manufacture module 2, In the step (2), the module 2 is transported to the bridging area together with a railing and parts for installing the railing, In step (3) above, the module 2 is erected at a predetermined location in the bridge area, The present invention relates to the bridge construction method according to claim 5, wherein in step (5) above, a railing is joined to the railing connecting arm provided on the module 2 using a railing installation component.

[0013] The invention according to claim 7 relates to the preceding step (1) writing The section (5) is incorporated, and the railings are joined to the railing connecting arms provided on module 2 to manufacture the bridge body. In step (2) above, the bridge structure is transported to the bridge construction area. In step (3) above, the bridge body is erected at a predetermined location in the bridge area, claim 6 Regarding the bridge construction method described.

[0014] The invention according to claim 8 relates to a bridge construction method according to claim 1, 2, or 5, wherein the two steel pipes constituting the bridge girder are fixed to steel plates provided on the ground at both ends in the direction of bridge construction, or to concrete bridge piers cast at the ends in the direction of bridge construction.

[0015] The invention according to claim 9 is, The bridge girders, crossbeams, deck slabs, and railings are lifted and installed in the bridge area using one selected from the group consisting of chain blocks, winches, and pulleys, and then joined together. The present invention relates to the bridge construction method according to feature 1, 2, or 5.

[0016] The invention according to claim 10 is the bridge girder, the transverse girder, the deck slab, the railing, and The aforementioned module Ru is The claim is characterized by being lifted and installed and joined in the aforementioned bridging area by one selected from the group consisting of a chain block, a winch, and a pulley. Section 2 Alternatively, the construction method of the bridge described in 5.

[0017] The invention according to claim 11 is a bridge constructed between slopes or embankments on opposite sides of a mountain stream or valley, or between banks of a well-maintained river, In the bridge area where the aforementioned bridge is constructed, the bridge girder is configured such that two steel pipes with a substantially circular cross-section are arranged parallel to each other in the direction of the bridge construction, A crossbeam is configured to join the two steel pipes at approximately right angles to each of the two steel pipes, with a fixed interval between them. A deck slab placed on top of the aforementioned bridge girder, The system is equipped with either a railing extending from each of the two steel pipes, or a railing erected on the floor slab. the law of nature, The steel materials constituting the bridge girder are painted to prevent corrosion due to wind and rain, and the transverse girders and the deck slab are adjusted to allow for on-site joining. The steel material constituting the crossbeam is selected from the group consisting of C-shaped steel, channel steel, and flat steel, and is painted to prevent corrosion due to wind and rain, and is adjusted to be joined to the two steel pipes in the field. The aforementioned deck slab is composed of one or more materials selected from the group consisting of wood, metal, concrete, carbon, synthetic resin, fiber, ceramic, concrete, glass, and stone, and is configured to have a bending moment that allows vehicles to pass over it, and is adjusted to be joined in place with the two circular steel pipes. The railing is constructed by arranging multiple posts in a row to prevent pedestrians from falling. This relates to a bridge characterized by the following features. [Effects of the Invention]

[0018] According to the invention of claim 1, the bridge girders, cross girders, deck slabs, and railings, which have been prepared in advance, are transported to the bridge construction site, and the bridge is completed in only four steps at the bridge construction site. This provides the effect of providing a bridge construction method that allows for easy construction with a simple structure. Furthermore, the bridge girders, crossbeams, deck slabs, and railings all offer excellent durability while remaining lightweight.

[0019] According to the invention of claim 2, by pre-connecting the bridge girders with the transverse girders to create modules, and then transporting them to the bridge construction site together with the deck and railings, the bridge can be completed in only three steps at the bridge construction site. This provides a bridge construction method that allows for a simpler and more compact structure to be built more easily. Furthermore, the bridge girders, crossbeams, deck slabs, and railings all offer excellent durability while remaining lightweight.

[0020] According to the invention of claim 3, by placing and joining the deck slab to the module in advance and transporting it to the bridge construction area as module 2 together with the railing, the bridge can be completed in only two steps at the bridge construction area, thus providing a bridge construction method that is simpler and more compact and easier to construct.

[0021] According to the invention of claim 4, since the railings are placed and joined to module 2 in advance and the completed bridge body is transported to the bridge construction site, the bridge is completed in the bridge construction site by only the process of installing the bridge body. This provides the effect of providing a bridge construction method that is simpler and more compact and easier to construct.

[0022] According to the invention of claim 5, by pre-connecting the bridge girders with the transverse girders to create modules, and then transporting them to the bridge construction site together with the deck and railings, the bridge can be completed in only three steps at the bridge construction site. This provides a bridge construction method that is simpler and more compact, and can be built more easily. Furthermore, the bridge girders, crossbeams, deck slabs, and railings all offer excellent durability while remaining lightweight.

[0023] According to the invention of claim 6, by placing and joining the deck slab to the module in advance and transporting it to the bridge construction area as module 2 together with the railing, the bridge can be completed in only two steps at the bridge construction area, thus providing a bridge construction method that is simpler and more compact and easier to construct.

[0024] According to the invention of claim 7, since the railings are attached to module 2 in advance and the completed bridge body is transported to the bridge construction site, the bridge is completed in the bridge construction site by only the process of installing the bridge body. This provides the effect of providing a bridge construction method that is simpler and more compact and easier to construct.

[0025] The invention according to claim 8 provides a bridge construction method and a bridge that can be easily erected in a short period of time while ensuring safety and durability.

[0026] According to the invention of claim 9, Because it does not require large heavy machinery, this method allows for the construction of bridges that can be easily erected in a short period of time even in mountainous, remote areas, valleys, or other places with undeveloped roads and no available engineers, while ensuring safety and durability.

[0027] The invention according to claim 10 provides a bridge construction method and a bridge that can be easily erected in a short period of time even in mountainous and remote areas, valleys, roads, and other places where roads are undeveloped and there are no engineers, because large heavy machinery is not required, and thus safety and durability are ensured.

[0028] The invention according to claim 11 provides a bridge construction method and a bridge that can be easily erected in a short period of time, even in mountainous and remote areas, valleys, or places with undeveloped roads and no engineers, where it is difficult to prepare large heavy machinery, and where safety and durability are ensured. Furthermore, the bridge girders, crossbeams, deck slabs, and railings all offer excellent durability while remaining lightweight. [Brief explanation of the drawing]

[0029] [Figure 1a] This is a diagram illustrating the process of a bridge construction method according to one embodiment of the present invention, and is a perspective view showing the state after the completion of the process (process 1) in which two steel pipes with a substantially circular cross-section, which have been prepared in advance for joining, are placed parallel to each other in the bridge direction in the bridge area to form a bridge girder. [Figure 1b] This diagram shows support brackets for connecting crossbeams, which are pre-welded to a circular steel pipe. [Figure 1c] This is a top view of a support bracket for connecting a crossbeam, which is pre-welded to a circular steel pipe. [Figure 2] This is a perspective view diagram illustrating the completed state after step 2, in which a transverse girder is joined to each of the two circular steel pipes that make up the bridge girder installed in step 1, at approximately right angles and at regular intervals, so as to connect the two steel pipes. [Figure 3] This is a plan view of the end face of a circular steel pipe with a support bracket pre-welded to it, and a crossbeam attached to it. [Figure 4] This is a process diagram illustrating the state after the process of placing the pre-fabricated deck slab on top of the bridge girder (process 3) has been completed, showing a cross-sectional view of the bridge body midway along its longitudinal direction. [Figure 5] This is a process diagram illustrating the state after the process (step 4) of placing and joining the pre-fabricated railings on the deck slab has been completed, shown as a cross-sectional view of the bridge structure midway along its longitudinal direction. [Figure 6] This is a perspective view of the completed bridge. [Figure 7] This is a plan view of the end face of a circular steel pipe with a railing attached to a railing connecting arm. [Modes for carrying out the invention]

[0030] <Embodiment 1> The bridge construction method according to Embodiment 1 will be described in detail below with reference to the attached drawings. As shown in Figure 1a, (Step 1) involves placing two steel pipes with a roughly circular cross-section (hereinafter referred to as "circular steel pipes") parallel to each other across the bridge area to form a bridge girder (1). These circular steel pipes (1) are pre-treated for corrosion resistance, and support fittings for joining are welded to them. The circular steel pipes used in this embodiment are not limited, but for example, those with a length of 12,000 mm, a diameter of 600 mm, and a thickness of 12 mm are used. <Support fittings for connecting and fastening to bridge abutments or piers> Support fittings are pre-welded to connect the circular steel pipe (1) to the steel plates (not shown) installed to serve as bridge abutments, or to the support members (not shown) fixed to the pre-cast concrete bridge piers (not shown). These fittings must be prepared on the contact surfaces at both ends of the two circular steel pipes (1). <Support bracket for joining crossbeams> Support brackets (s) are welded to the part of the circular diameter horizontally above the ground surface where the distance between the two circular steel pipes (1) is narrowest, so that the crossbeam (2) can be installed. To enable the crossbeam (2) to be installed perpendicular to the circular steel pipes (1) at equal intervals, it is necessary to install the support brackets (s) at the same position on the two circular steel pipes (1). The shape and structure of the support brackets (s) are not limited to a specific type, but for example, as shown in Figures 1b and 1c, a support bracket (s) is preferably used in which the joint with the circular steel pipe (1) is not straight but is processed into a curved shape with a curvature approximately the same as the curvature of the circular steel pipe (1), and three bolt insertion holes (h1) are drilled.

[0031] As shown in Figure 2, in (Step 2), steel members that will form the crossbeams (2) are joined to the circular steel pipe (1) at right angles and at equal intervals. The steel members that make up the crossbeams (2) can be selected from the group consisting of C-shaped steel, channel steel, and flat steel. In this embodiment, C-shaped steel with a length of 900 mm is used, but it is not limited to this. As shown in Figures 1b and 1c, the transverse girder (2) is joined to the circular steel pipe (1) using bolts and nuts or other fastening means, with support fittings (s) pre-welded to the pipe. Needless to say, any fastening means is not limited to bolts and nuts, as long as it is obvious to those skilled in the art. The role of this transverse girder (2) is to increase the strength of the bridge and maintain the parallelism of the bridge girder (1), which is made up of two circular steel pipes. To reduce the amount of work required in the bridge construction area, bolt holes for joining to the support fittings (s) are pre-drilled in the transverse girder (2). Figure 3 shows a view from the X direction of a crossbeam (2) joined to a support fitting (s) welded to a circular steel pipe (1).

[0032] As shown in Figure 4, in (Step 3), the floor slab (3) is placed and fixed on the top of the circular steel pipe (1). In this embodiment, a floor slab (3) made of joined pieces of wood (12,000 mm long, 2,800 mm wide) is used. The wood used was 200 mm wide and 60 mm thick. The configuration of the deck slab (3) can also be such that it is bound together with wire ropes to surround the two circular steel pipes.

[0033] As shown in Figure 5, in (Step 4), the railing (4) is joined to the deck slab (3). In this embodiment, the railing (4) is 900 mm high and 200 mm wide. Figure 6 shows an overhead view of the completed bridge (A). In this embodiment, the railing (4) is provided on the deck slab (3), but the method of installing the railing (4) is not limited to this. It can be directly attached to the circular steel pipe (1), or indirectly attached via arms, as will be described later.

[0034] In this embodiment, the bridge girders (1), crossbeams (2), deck slabs (3), and railings (4) are each transported to the bridge construction site, and construction at the site is completed in one day. The two circular steel pipes (1) that make up the bridge girders are transported by floating them down the river from upstream and then lifted up with a winch and erected. The joining of the bridge girders (1) and crossbeams (2), the placement of the deck slabs (3) on the bridge girders (1), and the fixing of the railings (4) to the deck slabs (3) are all done using bolts and nuts, so this can be done quickly by hand. The bridge (A) according to this embodiment has sufficient strength to allow large trucks to pass over it if the bridge length is up to 10m, and sufficient strength to allow ordinary automobiles to pass over it if the bridge length is up to 30m. Further cost reductions can be achieved by using recycled materials for the two circular steel pipes (1) that make up the bridge girder. The steel materials (2) that make up the crossbeams can be C-shaped steel, channel steel, or other shaped steel, flat steel, steel pipes, etc. The deck slab (3) is prepared using readily available materials from the market, such as wood, decking boards, metal, concrete, carbon, synthetic resin, fiber, ceramic, glass, and stone. The railing (4) can be made from wood, metal, etc., or guardrails can be used. In this embodiment, after calculating the tensile and shear forces acting on each bolt, high-strength hexagonal bolts with a shank length of 40 mm are used for all bolts.

[0035] In a modified version of this embodiment, in a remote area of ​​Southeast Asia, bamboo piles were driven into the soft ground as support piles, concrete was poured to pre-construct bridge abutments, and the prepared bridge girders (1), cross girders (2), deck slabs (3), and railings (4) were transported by truck overland, and the bridge was completed in 3 hours by 4 local workers. In this case, locally sourced bamboo piles were used for the support piles of the bridge abutment, and the deck slab (3) was also manufactured using locally sourced materials, resulting in a shorter construction period and cost reduction.

[0036] <Embodiment 2> According to this embodiment, the bridge girder (1) of Embodiment 1 described above is joined with the transverse girder (2) in advance to manufacture it as a module (modularization), and then transported to the bridge construction site together with the deck slab (3) and railings (4). This has the advantage that the bridge can be completed in only three steps at the bridge construction site (see Figure 3). Therefore, it is possible to provide a bridge construction method that allows for even simpler construction with a simple and compact structure. According to a modified version of this embodiment, the deck slab (3) is placed and joined to the module in advance, and then transported to the bridge area as module 2 together with the railing (4). As a result, the bridge can be completed in only two steps at the bridge area, making it possible to construct it even more easily with a simple and compact structure (see Figure 4). In another modification of this embodiment, the railing (3) is placed and joined to the module 2 in advance, and the completed bridge body (A) is transported to the bridge construction site. In the bridge construction site, the bridge is completed by only the process of installing the bridge body (A) (see Figure 6).

[0037] In yet another embodiment, the bridge structure assembled in the factory is towed to the bridge construction site and installed and used as a floating pier.

[0038] As shown in Figure 7, by pre-welding arm sections (p) for attaching the railing to a circular steel pipe, and then attaching the railing (4) to the arm sections (p) of the circular steel pipe (1) with the arm sections (p) attached, the module can be manufactured and then transported to the bridge area together with the transverse girders (2) and deck slabs (3), thereby further simplifying the process in the bridge area.

[0039] In previous specifications, various embodiments have been described with reference to the accompanying drawings. However, it will be apparent that various modifications and changes can be made to them, and additional embodiments can be implemented, without departing from the broader scope of this disclosure as described in the claims below. Accordingly, this specification and the drawings should be understood as illustrative rather than restrictive. [Industrial applicability]

[0040] According to the present invention, it is possible to provide a bridge with a simple structure that can be easily constructed in mountainous, remote areas, streams, valleys, and other places where roads are undeveloped and engineers are unavailable, where it is difficult to prepare large heavy machinery. More specifically, it is possible to provide a bridge construction method and a bridge that can be easily erected in a short period of time while ensuring safety and durability. In other words, it is possible to provide bridges even in mountain streams or valleys where the only means of passage is narrow roads, and also in rural areas overseas where it is difficult to prepare engineers and heavy machinery. Furthermore, it can be used for the rapid restoration of roads and bridges that have become impassable in the event of a disaster, and for the urgent securing of communication routes. [Explanation of Symbols]

[0041] 1 Bridge girder 2 crossbeam 3 Floor slab 4. Railing A Bridge

Claims

1. A construction method for bridges with a length of 10m to 30m, which are constructed between slopes or embankments on opposite sides of a mountain stream or valley, or between banks of a well-maintained river. (1) A step of installing a bridge girder in the bridge area where the bridge spans, in the direction of the bridge, by arranging two steel pipes with a substantially circular cross-section, each having support fittings pre-welded at equal intervals and three bolt insertion holes drilled in them, parallel to each other so that the support fittings face each other, (2) A step of joining a plurality of crossbeams, which have bolt insertion holes pre-drilled so that they can be joined on-site with bolts and nuts via the support fittings, to the two steel pipes that are arranged parallel to each other in step (1) above, (3) A step of placing a deck slab on the bridge girder installed in step (1) above, (4) The process includes the step of erecting a railing on the floor slab obtained in step (3), The steel pipes are painted to prevent corrosion due to wind and rain, and the steel pipes are pre-installed with bolts or bolt holes for joining the deck slabs, and are adjusted so that the crossbeams and the deck slabs can be joined in place. The steel material constituting the crossbeam is selected from the group consisting of C-shaped steel, channel steel, and flat steel, and is painted to prevent corrosion due to wind and rain. The aforementioned floor slab is composed of one or more materials selected from the group consisting of wood, metal, concrete, carbon, synthetic resin, fiber, ceramic, concrete, glass, and stone, and is configured to have a bending moment that allows vehicles to pass over it, and bolt insertion holes are pre-drilled in the two steel pipes so that they can be joined in place with bolts or bolt insertion holes pre-disposed in the steel pipes, and bolt insertion holes are pre-drilled for fixing the railing, A bridge construction method characterized in that the railing is configured to prevent pedestrians from falling by arranging multiple columns in a row, and each of the multiple columns is pre-installed with bolts for fixing to the deck slab, so that it can be joined to the deck slab in the field.

2. A construction method for bridges with a length of 10m to 30m, which are constructed between slopes or embankments on opposite sides of a mountain stream or valley, or between banks of a well-maintained river. (1) A process of manufacturing a module by joining a bridge girder, which is made by arranging two steel pipes with a substantially circular cross-section, each having support fittings pre-welded at equal intervals at a first location, so that the support fittings face each other, and a plurality of cross girders, each having pre-welded bolt fittings so that they can be joined via the support fittings, with bolts and nuts, (2) A step of transporting the module, together with a deck slab having pre-drilled bolt holes and a railing with pre-installed bolts for fixing to the deck slab, to the bridge construction area by waterway or land, (3) The process of erecting the module at a predetermined location in the bridge area, (4) A step of placing the floor slab on the bolts or bolt holes that have been pre-disposed in the steel pipe of the module and joining them together, (5) The process includes the step of joining the railing to the module by inserting bolts provided on the railing into bolt insertion holes pre-drilled in the floor slab joined to the module in step (4), The steel pipes constituting the bridge girder are painted to prevent corrosion due to wind and rain, and the cross girders and deck slabs are adjusted to allow for on-site joining. The steel material constituting the crossbeam is selected from the group consisting of C-shaped steel, channel steel, and flat steel, and is painted to prevent corrosion due to wind and rain, and is adjusted to be joined to the two steel pipes in the field. The aforementioned floor slab is composed of one or more materials selected from the group consisting of wood, metal, concrete, carbon, synthetic resin, fiber, ceramic, concrete, glass, and stone, and is configured to have a bending moment that allows vehicles to pass over it, and is adjusted to be joined in place with the two aforementioned steel pipes. A bridge construction method characterized in that the railing is configured to prevent pedestrians from falling by arranging multiple pillars in a row.

3. In step (1) above, step (4) above is incorporated, the floor slab is placed on the module, and the floor slab is joined to the module to manufacture module 2. In step (2) above, the module 2 is transported to the bridge area together with the railing. In step (3) above, the module 2 is erected at a predetermined location in the bridge area, The bridge construction method according to claim 2, wherein in step (5) above, the railing is placed on the module 2 and the railing is joined to the module 2 using bolts and nuts.

4. In step (1) above, step (5) above is incorporated, the railing is placed on the module 2, and the railing is joined to the module 2 to manufacture the bridge body. In step (2) above, the bridge structure is transported to the bridge construction area. The bridge construction method according to claim 3, wherein in step (3) above, the bridge body is erected at a predetermined location in the bridge area.

5. A construction method for bridges with a length of 10m to 30m, which are constructed between slopes or embankments on opposite sides of a mountain stream or valley, or between banks of a well-maintained river. (1) A step of manufacturing a module comprising a bridge girder formed by joining a bridge girder, which is made of two steel pipes with a substantially circular cross-section, each having support fittings pre-welded at equal intervals at a first location, with the support fittings facing each other, and a plurality of cross girders having pre-welded bolt fittings so as to be joinable via the support fittings, with each of the two steel pipes being provided with arms for connecting to railings, and a step of manufacturing a module, (2) A step of transporting the module, together with a deck slab having pre-drilled bolt holes and a railing with pre-installed bolts for securing it to the arm, to the bridge construction area by waterway or land, (3) The process of erecting the module at a predetermined location in the bridge area, (4) A step of placing and joining a floor slab on bolts or bolt holes that have been pre-disposed in the steel pipe of the module, via the bolt holes, (5) The process includes connecting and joining the railings via bolts that have been pre-displaced to the arms for railing connection provided on the two steel pipes, The steel pipes constituting the bridge girder are painted to prevent corrosion due to wind and rain, and the cross girders and deck slabs are adjusted to allow for on-site joining. The steel material constituting the crossbeam is selected from the group consisting of C-shaped steel, channel steel, and flat steel, and is painted to prevent corrosion due to wind and rain, and is adjusted to be joined to the two steel pipes in the field. The aforementioned floor slab is composed of one or more materials selected from the group consisting of wood, metal, concrete, carbon, synthetic resin, fiber, ceramic, concrete, glass, and stone, and is configured to have a bending moment that allows vehicles to pass over it, and is adjusted to be joined in place with the two aforementioned steel pipes. A bridge construction method characterized in that the railing is configured to prevent pedestrians from falling by arranging multiple pillars in a row.

6. In step (1) above, step (4) above is incorporated, the floor slab is placed on the module, and the floor slab is joined to the module to manufacture module 2. In step (2) above, the module 2 is transported to the bridge area together with the railing. In step (3) above, the module 2 is erected at a predetermined location in the bridge area, The bridge construction method according to claim 5, wherein in step (5) above, the railing is joined to the arm portion for railing connection provided on the module 2 via the bolt that has been pre-disposed.

7. In step (1) above, step (5) above is incorporated, and the railing is joined to the arm portion for railing connection provided on the module 2 to manufacture the bridge body. In step (2) above, the bridge structure is transported to the bridge construction area. The bridge construction method according to claim 6, wherein in step (3) above, the bridge body is erected at a predetermined location in the bridge area.

8. The bridge construction method according to claim 1, 2, or 5, wherein the two steel pipes constituting the bridge girder are fixed on steel plates provided on the ground at both ends in the direction of bridge construction, or on concrete bridge piers cast at the ends in the direction of bridge construction.

9. The bridge construction method according to claim 1, 2, or 5, characterized in that the bridge girders, cross girders, deck slabs, and railings are lifted and installed in the bridge area using one selected from the group consisting of chain blocks, winches, and pulleys, and then joined together.

10. The bridge construction method according to claim 2 or 5, characterized in that the bridge girders, cross girders, deck slabs, railings, and modules are lifted and installed in the bridge area using one selected from the group consisting of chain blocks, winches, and pulleys, and then joined together.

11. A bridge constructed between slopes or embankments on opposite sides of a mountain stream or valley, or between banks of a well-maintained river. In the bridge area where the aforementioned bridge is constructed, two steel pipes with a roughly circular cross-section, each having three bolt insertion holes pre-welded at equal intervals, are arranged parallel to each other in the bridge direction, with the support fittings facing each other. Multiple crossbeams, each having bolt insertion holes pre-drilled in two steel pipes so that they can be joined on-site using bolts and nuts via the support fittings, and the multiple crossbeams joined to the two steel pipes by bolts and nuts, A deck slab placed on the bridge girder, the deck slab being joined by bolts or bolt holes pre-disposed in the steel pipes and bolt holes pre-drilled in the deck slab via bolts and nuts, Each of the two steel pipes is equipped with a railing that is pre-extended, or a railing that is erected on the floor slab with bolts for fixing it pre-placed. The steel pipes constituting the bridge girder are painted to prevent corrosion due to wind and rain, and the cross girders and deck slabs are adjusted to allow for on-site joining. The steel material constituting the crossbeam is selected from the group consisting of C-shaped steel, channel steel, and flat steel, and is painted to prevent corrosion due to wind and rain, and is adjusted to be joined to the two steel pipes in the field. The aforementioned floor slab is composed of one or more materials selected from the group consisting of wood, metal, concrete, carbon, synthetic resin, fiber, ceramic, concrete, glass, and stone, and is configured to have a bending moment that allows vehicles to pass over it, and is adjusted to be joined in place with the two aforementioned steel pipes. The aforementioned railing is characterized by being configured to prevent pedestrians from falling, with multiple pillars arranged in a row.

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