Preflex steel pipe girder and bridge construction method

Abstract

The present invention relates to a preflex steel pipe girder and a bridge construction method, wherein the method for manufacturing a steel pipe girder used in bridge construction comprises the following steps: (a) forming a lower slit (111) in a lower part of the steel pipe (110) and an upper slit (112) in an upper part of the steel pipe (110); (b) placing the steel pipe (110) with the lower slit (111) and upper slit (112) formed thereon on a loading platform and applying a load to the steel pipe (110) to deform the linear shape of the steel pipe (110) so that it becomes a convex linear shape facing downward; (c) inserting a vertical plate (120) through the lower slit (111) and upper slit (112) while the load is applied to the steel pipe (110), and then welding and attaching it; and (d) removing the load to introduce prestress into the steel pipe (110).

Description

Technology Field

[0001] The present invention relates to a pre-stressed preflex steel pipe girder and a bridge construction method using the same.

[0002] This invention is based on the support of the following national research and development project.

[0003] Item name Details Project Unique Number 2025-RISE-14-004 Assignment Number 2025-RISE-14-004 Buddha name Ministry of Education Project Management (Specialized) Agency Name Jeollanam-do RISE Center Research Project Name Jeonnam Regional Innovation Center University Support System (RISE) Research Project Title R. Regional Innovation Challenge Project implementing organization name Dongshin University Research period 2025. 08. 01. ~ 2030. 02. 28. Background Technology

[0004] A bridge is a civil engineering structure that connects spaces and provides a passage for the movement of people, vehicles, trains, water resources, cargo, and more.

[0005] Precast concrete (PC) girders, plate girders, and steel pipe girders are widely used for bridge construction.

[0006] Double-tube girders have a rounded curved shape instead of a rough rectangular box, so they are aesthetically pleasing and are widely used in pedestrian bridges, urban overpasses, and scenic bridges. Since the cross-section of the steel tube is circular, it can resist forces coming from all directions uniformly, resulting in excellent torsional rigidity. It also has the advantages of enabling economical design and making it easy to fabricate curved bridges.

[0007] Steel pipes are used either as hollow pipes as they are or as composite girders (Concrete Filled Tube Girders) by filling the inside of the pipes with concrete.

[0008] However, such conventional steel pipe girders use circular steel pipes as they are, resulting in insufficient member efficiency and a need to improve load-bearing capacity. Prior art literature

[0009] Korean Registered Patent Publication No. 10-2541549 The problem to be solved

[0010] To improve upon the problems of the conventional technology described above, the present invention aims to provide a preflex steel pipe girder that allows for the efficient use of members by introducing prestress into the steel pipe girder, and a bridge construction method using the same. means of solving the problem

[0011] The present invention provides a method for manufacturing a steel pipe girder used in bridge construction, comprising the steps of: (a) forming a lower slit (111) in a lower part of the steel pipe (110) and an upper slit (112) in an upper part of the steel pipe (110); (b) placing the steel pipe (110) with the lower slit (111) and upper slit (112) formed thereon on a loading platform and applying a load to the steel pipe (110) to deform the linear shape of the steel pipe (110) so that it becomes a convex linear shape facing downward; (c) inserting a vertical plate (120) through the lower slit (111) and upper slit (112) while the load is applied to the steel pipe (110), and then welding and attaching it; and (d) removing the load to introduce prestress into the steel pipe (110).

[0012] In the above step (c), the process of attaching a lower curved plate (130) to the steel pipe (110) by welding from below the vertical plate (120) and / or attaching an upper curved plate (140) to the steel pipe (110) by welding from above the vertical plate (120) is further carried out.

[0013] After step (a) and before step (b), a fixing member (150) is welded and attached to the steel pipe (110) so as to cross the lower slit (111) and / or the upper slit (112) to prevent the lower slit (111) and / or the upper slit (112) from spreading due to deformation of the steel pipe (110).

[0014] The length of the steel pipe (110) in the longitudinal direction of the vertical plate (120) is equal to or shorter than the length of the steel pipe (110) in the longitudinal direction of the lower slit (111) and the upper slit (112), and the length of the steel pipe (110) in the longitudinal direction of the fixing member (150) is shorter than the length of the steel pipe (110) in the longitudinal direction of the vertical plate (120).

[0015] The lower slit (111) and the upper slit (112) are provided in a direction parallel to the longitudinal direction of the steel pipe (110), and the lengths of the lower slit (111) and the upper slit (112) are 1 / 10 to 2 / 10 of the length of the steel pipe (110).

[0016] The present invention provides a preflex steel pipe girder manufactured by the above manufacturing method.

[0017] The present invention provides a bridge construction method comprising: (a) a step of installing a plurality of substructures spaced apart in the bridge axis direction; (b) a step of installing the preflex steel pipe girder (100) on the upper part of the substructures; and (c) a step of constructing a deck plate on the upper part of the preflex steel pipe girder (100).

[0018] The present invention provides a bridge constructed by the above bridge construction method.

[0019] The present invention provides a bridge comprising: a plurality of substructures installed spaced apart in the longitudinal direction; a preflex steel pipe girder (100) provided on the upper part of the substructures; and a deck plate provided on the upper part of the preflex steel pipe girder (100). Effects of the invention

[0020] The preflex steel pipe girder and bridge construction method of the present invention have the following effects.

[0021] First, prestress can be introduced into the steel pipe by attaching vertical plates, etc., to the steel pipe deformed by applying a load, thereby allowing for the simple introduction of prestress without structural changes to the steel pipe or the addition of special members. As a result, the preflex steel pipe girder of the present invention, having introduced prestress, can reduce the cross-sectional area of ​​the steel pipe girder and enable efficient design.

[0022] In particular, by attaching a lower surface curved plate and / or an upper surface curved plate to the lower and / or upper part of the steel pipe to introduce prestress into the steel pipe, the flexural stiffness and load-carrying capacity of the girder are increased.

[0023] Second, the separation of the lower slit and the upper slit that may occur due to steel pipe deformation can be prevented by a fixing member attached to the lower slit and / or the upper slit.

[0024] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description in the claims. Brief explanation of the drawing

[0025] Figure 1 illustrates the manufacturing process of a preflex steel pipe girder that introduces prestress into a steel pipe, and is an example in which a vertical plate is attached to suppress restoring force. Figure 2 illustrates the manufacturing process of a preflex steel pipe girder that introduces prestress into a steel pipe, and is an example in which a vertical plate and a bottom curved plate are attached to suppress restoring force. Figure 3 illustrates the manufacturing process of a preflex steel pipe girder that introduces prestress into a steel pipe, and is an example in which a vertical plate and an upper curved plate are attached to suppress restoring force. Figure 4 illustrates the manufacturing process of a preflex steel pipe girder that introduces prestress into a steel pipe, and is an example in which a vertical plate, a lower curved plate, and an upper curved plate are attached to suppress restoring force. Figure 5 illustrates the manufacturing process of a preflex steel pipe girder that introduces prestress into a steel pipe, and is an example in which a fixing member is attached to the lower surface of the steel pipe to prevent the lower slit from spreading during the load application process. Figure 6 illustrates the manufacturing process of a preflex steel pipe girder that introduces prestress into a steel pipe, and is an example in which a fixing member is attached to the upper surface of the steel pipe to prevent the upper slit from spreading during the load application process. Figure 7 illustrates the manufacturing process of a preflex steel pipe girder that introduces prestress into a steel pipe, and is an embodiment in which fixing members are attached to the lower and upper surfaces of the steel pipe to prevent the lower slit and upper slit from spreading apart during the load application process. Specific details for implementing the invention

[0026] Embodiments of the present invention are described in detail below with reference to the attached drawings so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are given similar reference numerals. Throughout the specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0027] The present invention relates to a pre-stressed preflex steel pipe girder, a bridge using the same, and a method for constructing the same.

[0028] First, a pre-stressed preflex steel tube girder (100) is described, and then a method for constructing a bridge is described.

[0029] The preflex steel pipe girder (100) and steel pipe (110) of the present invention are provided with their length direction parallel to the length direction (bridge axis direction) of the bridge. The left-right direction of the long steel pipe shown in the drawing becomes the length direction of the steel pipe girder and the bridge.

[0030] The preflex steel pipe girder (100) of the present invention comprises a steel pipe (110), a lower slit (111) and an upper slit (112) formed in the steel pipe (110), and a vertical plate (120) inserted and attached to the lower slit (111) and the upper slit (112). In another embodiment, a lower curved plate (130), an upper curved plate (140), and a fixing member (150) may be further included.

[0031] Among the components of the present invention, the lower slit (111), upper slit (112), lower curved plate (130), and upper curved plate (140) are distinguished as the lower and upper parts based on the manufacturing process of the preflex steel pipe girder as shown in the drawing. When the steel pipe girder (100) is installed on a substructure after manufacturing is completed, the completed steel pipe girder (100) can be used by inverting it vertically (when inverted vertically, it becomes a convex shape facing upward), and at this time, the lower slit (111) and lower curved plate (130) can be located on the upper part, and the upper slit (112) and upper curved plate (140) can be located on the lower part.

[0032] First, the manufacturing process of the preflex steel pipe girder (100) is explained.

[0033] The preflex steel pipe girder (100) of the present invention is manufactured by applying a load to a straight steel pipe to deform it, and attaching a vertical plate (120) (a lower curved plate (130) and / or an upper curved plate (140) may be additionally attached depending on the embodiment) to the steel pipe to restrain the restoration of the steel pipe and introduce prestress into the steel pipe.

[0034] First, to secure a space for inserting a vertical plate (120), a lower slit (111) is formed in a lower part of the steel pipe (110), and an upper slit (112) is formed in an upper part of the steel pipe (110).

[0035] The lower slit (111) and the upper slit (112) are narrow through-spaces provided in a direction parallel to the longitudinal direction of the steel pipe (110), and the lengths of the lower slit (111) and the upper slit (112) can be 1 / 10 to 2 / 10 of the length of the steel pipe (110).

[0036] It is preferable that the width of the lower slit (111) and the upper slit (112) be minimized within the range through which the vertical plate (120) passes.

[0037] Next, the steel pipe (110) with the lower slit (111) and upper slit (112) formed thereon is placed on a loading platform, and a load is applied to the steel pipe (110) to deform the linear shape of the steel pipe (110) so that it becomes a convex shape facing downward. When a load is applied to the steel pipe, the linear shape of the steel pipe, which was originally straight, is deformed into a convex shape facing downward.

[0038] With the deformed state of the steel pipe maintained and a load applied to the steel pipe (110), a vertical plate (120) is inserted through the lower slit (111) and the upper slit (112), welded, and attached to integrate the steel pipe and the vertical plate (120).

[0039] After attaching the vertical plate (120) while the steel pipe is in a deformed state, and then removing the load, the steel pipe has a force that tries to return to its original straight line, but since the restoring force trying to return to a straight line is resisted by the vertical plate (120), prestress trying to return to a straight line is introduced into the steel pipe.

[0040] In the present invention, by using a pre-flex steel pipe girder (100) with prestress introduced in the manner described above in a bridge, the cross-sectional area of ​​the bridge member can be reduced, and economical construction can be achieved.

[0041] Depending on the location, a positive (+) bending moment (a bending moment that causes convex deformation downward) or a negative (-) bending moment (a bending moment that causes convex deformation upward) may act on the girder.

[0042] In order to reinforce the lower part of the steel pipe (110) at a location where a positive (+) bending moment acts and to reinforce the upper part of the steel pipe (110) at a location where a negative (-) bending moment acts, the present invention may provide a lower curved plate (130) and / or an upper curved plate (140).

[0043] The lower curved plate (130) can reinforce the tensile strength of the lower part of the steel pipe girder, and the upper curved plate (140) can reinforce the tensile strength of the upper part of the steel pipe girder (however, when installing the preflex steel pipe girder of the present invention on a bridge substructure, it can be used by inverting it vertically from the state of (f) in FIGS. 1, 2, 3, and 4; therefore, when installed by inverting it vertically, the lower curved plate (130) reinforces the upper part of the steel pipe girder, and the upper curved plate (140) reinforces the lower part of the steel pipe girder).

[0044] To this end, during the process of welding the vertical plate (120), the process of attaching the lower curved plate (130) by welding from below the vertical plate (120) and / or attaching the upper curved plate (140) to the steel pipe (110) by welding from above the vertical plate (120) may be additionally performed.

[0045] The lower curved plate (130) and the upper curved plate (140) may be provided in an arc shape that can be closely attached to the outer surface of the steel pipe, and the length in the direction parallel to the length direction of the steel pipe may be formed longer than the lower slit (111) and the upper slit (112), or shorter.

[0046] When a lower curved plate (130) and / or an upper curved plate (140) are attached, it becomes possible to resist the straight restoring force of the steel pipe more strongly after the load is removed.

[0047] In addition, when a steel pipe is deformed while a slit is formed in it, the slit may widen depending on the specifications of the steel pipe and the amount of deformation.

[0048] In the present invention, to prevent the lower slit (111) and / or upper slit (112) from opening during the deformation process of the steel pipe, a fixing member (150) can be welded and attached to the steel pipe (110).

[0049] Welding and attaching the fixed member (150) is done after forming the lower slit (111) and the upper slit (112) and before applying the load.

[0050] A fixing member (150) is welded and attached to the steel pipe (110) so as to cross the lower slit (111) and / or the upper slit (112) to prevent the lower slit (111) and / or the upper slit (112) from spreading due to deformation of the steel pipe (110).

[0051] The fixing member (150) may be provided in the form of a short cut of the lower curved plate (130) or the upper curved plate (140). The length of the fixing member (150) in a direction parallel to the longitudinal direction of the steel pipe may be 1 / 20 to 1 / 10 of the lower slit (111) and the upper slit (112).

[0052] It is preferable that the length of the steel pipe (110) in the longitudinal direction of the vertical plate (120) is equal to or shorter than the length of the steel pipe (110) in the longitudinal direction of the lower slit (111) and the upper slit (112), and that the length of the steel pipe (110) in the longitudinal direction of the fixing member (150) is shorter than the length of the steel pipe (110) in the longitudinal direction of the vertical plate (120).

[0053] The above fixing member (150) may be provided in multiple numbers at the upper and lower parts of the steel pipe, respectively.

[0054] When installing the preflex steel pipe girder (100) of the present invention produced by the above process on an actual bridge substructure, it can be used by inverting it vertically in the state (f) of FIGS. 1 to 4 and the state (g) of FIGS. 5 to 7.

[0055] Below, a bridge construction method using the preflex steel pipe girder (100) described above is explained.

[0056] To construct the bridge, multiple substructures are first installed so as to be spaced apart in the longitudinal direction.

[0057] The fabrication of the preflex steel pipe girder (100) can proceed simultaneously with the installation process of the substructure.

[0058] When the construction of the substructure is completed, one or more preflex steel pipe girders (100) are installed on the upper part of the substructure in a direction perpendicular to the bridge axis.

[0059] When there are multiple installed preflex steel pipe girders (100), a cross beam can be installed between adjacent preflex steel pipe girders (100).

[0060] Once the installation of the preflex steel pipe girder (100) or the installation of the preflex steel pipe girder (100) and the cross beam is completed, a bridge deck is constructed on top of the preflex steel pipe girder (100).

[0061] The bridge deck may be provided as any one of PC deck, cast-in-place concrete, half deck, or temporary decking. Handrails may be installed if necessary.

[0062] A bridge using the preflex steel pipe girder (100) of the present invention can be used as an application facility for utilizing drones.

[0063] One way to utilize drones on bridges is for safety inspections and maintenance. Since bridges are often difficult for humans to access directly, drones can solve this problem.

[0064] Drones can take close-up shots of blind spots that are difficult for humans to see directly, such as the underside of bridge superstructures and the tops of piers, and use high-resolution cameras to detect minute defects, allowing for the precise identification of concrete cracks, exposed rebar, corrosion of steel pipes, and loosened bolts. Additionally, drones equipped with thermal imaging cameras can detect invisible internal bridge damage, leaks, and concrete spalling through temperature differences.

[0065] In addition, a drone can fly over the entire bridge to perform photogrammetry and build a 3D digital model based on the photogrammetry data. Through this 3D model, data can be constructed to accurately determine the current condition of the bridge and measure the location and size of damaged areas in millimeters. Additionally, the 3D model can be updated regularly to manage the history of the bridge.

[0066] The present invention has been described with reference to the embodiments illustrated in the drawings, but this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom.

[0067] Therefore, the true scope of technical protection of the present invention should be determined by the technical concept of the appended claims. Explanation of the symbols

[0068] 100. Preflex steel pipe girder 110. Steel pipe 111. Lower slit 112. Upper slit 120. Vertical plate 130. Curved bottom plate 140. Top surface curved plate 150. Fixing member

Claims

Claim 1 In a method for manufacturing a steel pipe girder used in bridge construction, prestress is introduced into the steel pipe (110) by a vertical plate (120) attached to a portion of the longitudinal center of the steel pipe (110), and the process of manufacturing the steel pipe girder into which prestress is introduced comprises: (a) a step of forming a lower slit (111) provided in a direction parallel to the longitudinal direction of the steel pipe (110) on a portion of the lower part of the steel pipe (110), and an upper slit (112) provided in a direction parallel to the longitudinal direction of the steel pipe (110) on a portion of the upper part of the steel pipe (110); (b) a step of placing the steel pipe (110) having the lower slit (111) and the upper slit (112) formed thereon on a loading platform and applying a load to the steel pipe (110) to deform the steel pipe (110) so that its linear shape becomes a convex shape facing downward; (c) a step of inserting a vertical plate (120) through the lower slit (111) and upper slit (112) while a load is applied to the steel pipe (110) and then welding and attaching it; (d) a step of removing the load to introduce prestress into the steel pipe (110), wherein the lengths of the lower slit (111) and upper slit (112) are 1 / 10 to 2 / 10 of the length of the steel pipe (110), and the method for manufacturing a preflex steel pipe girder is characterized by the following steps. Claim 2 delete Claim 3 A method for manufacturing a preflex steel pipe girder according to claim 1, wherein in step (c) above, the process of attaching a lower surface curved plate (130) to the steel pipe (110) by welding from below the vertical plate (120) and / or attaching an upper surface curved plate (140) to the steel pipe (110) by welding from above the vertical plate (120). Claim 4 A method for manufacturing a preflex steel pipe girder according to claim 3, wherein, after step (a) and before step (b), a fixing member (150) is welded and attached to the steel pipe (110) so as to cross the lower slit (111) and / or upper slit (112), thereby preventing the lower slit (111) and / or upper slit (112) from spreading due to deformation of the steel pipe (110). Claim 5 A method for manufacturing a preflex steel pipe girder according to claim 4, wherein the length of the steel pipe (110) in the longitudinal direction of the vertical plate (120) is equal to or shorter than the length of the steel pipe (110) in the longitudinal direction of the lower slit (111) and the upper slit (112), and the length of the steel pipe (110) in the longitudinal direction of the fixing member (150) is shorter than the length of the steel pipe (110) in the longitudinal direction of the vertical plate (120). Claim 6 delete Claim 7 A preflex steel pipe girder manufactured by the manufacturing method of any one of paragraphs 1, 3 to 5. Claim 8 A bridge construction method comprising: (a) a step of installing a plurality of substructures spaced apart in the bridge axis direction; (b) a step of installing the preflex steel pipe girder (100) of claim 7 on the upper part of the substructures; and (c) a step of constructing a deck plate on the upper part of the preflex steel pipe girder (100). Claim 9 A bridge constructed by the construction method of Paragraph 8. Claim 10 A bridge comprising: a plurality of substructures installed spaced apart in the longitudinal direction; a preflex steel pipe girder (100) of claim 7 provided on the upper part of the substructures; and a deck plate provided on the upper part of the preflex steel pipe girder (100).

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