Demolition methods for overbridges

Abstract

This invention provides a demolition method for overbridges of rigid-frame bridges, such as π-type rigid-frame bridges and portal-type rigid-frame bridges, which can be dismantled and removed without obstructing traffic beneath the overbridge. [Solution] The method for dismantling an overbridge includes a bent assembly and installation step, in which a bent is assembled and installed at a position inside the center of gravity at the time of cutting the span to prevent the cut superstructure from tipping over; a scaffolding assembly and installation step, in which scaffolding is assembled and installed to prevent the cut superstructure from falling; a counterweight installation step, in which a counterweight is loaded and installed at a position outside the center of gravity at the time of cutting to prevent the cut superstructure from tipping over; a span cutting step, in which the superstructure is cut at any position within the span; and a jacking-up step, in which the cut superstructure is jacked up with vertical jacks. The jacked-up superstructure is then moved outward in the direction of the bridge axis using a feeding device installed on the uppermost part of the bent and scaffolding for dismantling and removal.

Description

Technical Field

[0001] The present invention relates to a method for demolishing an overbridge installed to span over a line of a means of passage such as a highway, railway, or production line in a factory, such as an overpass or overline bridge, without blocking the passage of the means of passage, and demolishing the overbridge without obstructing the passage of the means of passage below.

Background Art

[0002] In recent years, cases have been increasing where overbridges such as overpasses and overline bridges installed over highways, railways, and production lines in factories built during the high-growth period are aging, or where removal is selected by comparing the usage frequency of the overbridge and its repair and inspection costs. Conventionally, for the demolition and removal work of overbridges, at night, the passage of the road under the overbridge was blocked, and a crane or other lifting machine was installed on the road under the overbridge for demolition and removal.

[0003] However, since infrastructure facilities of linear means of passage such as highways and railways have a great impact on many neighboring industries when traffic regulations such as traffic stops are imposed, there has been a strong desire to demolish the overbridge without obstructing the passage below.

[0004] For example, Patent Document 1 discloses a bridge removal method in which a work yard is set up in the open space below the bridge to be removed, and deck slabs of a predetermined length are transported to the work yard and sequentially crushed and removed, wherein the deck slabs are lifted in one span in one go by a gate-shaped lifting means equipped with a traveling means that can move along the bridge on both the left and right sides of the bridge and transported to the work yard, and the lifting means is configured to have two lifting devices erected on the traveling means, one at the front and one at the back, and a beam member that is installed to straddle the bridge by connecting the upper ends of the left and right lifting devices, respectively, and the lifting means is equipped with a total of four lifting devices, one at the front and one at the back and two at the left and right, and after the lifted deck slabs are transferred to the adjacent deck slabs, the work yard is set up below the removed deck slab section (see Claim 1 of the claims, paragraphs

[0029] to

[0076] of the specification, Figures 1 to 6 of the drawings, etc. of Patent Document 1).

[0005] The bridge removal method described in Patent Document 1 does not require a large workspace on the side of the bridge to be removed, and does not require cutting of the deck slab, allowing for removal in one go. However, even when applied to an overbridge, it is not possible to dismantle it without obstructing traffic beneath the overbridge.

[0006] Furthermore, Patent Document 2 describes a first step of lifting and separating a bridge structure on existing piers via a lifting and horizontal movement device, and then moving the bridge structure that has been lifted and separated on the existing piers via the lifting and horizontal movement device. A method for removing and dismantling a bridge is disclosed, characterized by comprising a second step of moving the bridge onto an adjacent bridge or road, and a third step of dismantling the bridge that has been moved onto the adjacent bridge or road at the location of the move using dismantling equipment (Claim 1 of the claims in Patent Document 2, paragraph of the specification).

[0007] ~

[0010] , see Figure 1 of the drawings, etc.).

[0007] The bridge removal and dismantling method described in Patent Document 2 is safe because no falling objects fall into the space beneath the bridge during dismantling, and because there is no need to install dismantling equipment in the space beneath the bridge, the work can be carried out in a short period of time without requiring traffic disruption, and if the bridges are continuous, the dismantling and removal work can be carried out continuously. However, the bridge removal and dismantling method described in Patent Document 2 is intended for concrete deck bridges, and there is a problem that it cannot be directly applied to overbridges of rigid-frame bridges such as π-type rigid-frame bridges and portal-type rigid-frame bridges because it does not adequately consider the removal of substructures such as bridge piers or means of lifting (raising) that exceeds the girder height.

[0008] Furthermore, Patent Document 3 discloses a method for dismantling and removing a swing bridge, proposed by the applicant of the present application, which includes a girder cutting step for cutting the bridge girder and a girder rotation step for swinging the girder upward around a pivot hinge at the lower part of the bridge pier or arch rib and rotating it to pull it towards the abutment (see Claim 1 of the claims, paragraphs

[0024] to

[0067] of the specification, and Figures 1 to 33 of the drawings of Patent Document 3).

[0009] However, the method for dismantling and removing a swing bridge described in Patent Document 3 can only be applied to arch bridges, and, similar to the invention described in Patent Document 2, it has the problem of not being applicable to overbridges of rigid-frame bridges such as π-type rigid-frame bridges and portal-type rigid-frame bridges. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2006-336392 [Patent Document 2] Japanese Patent Application Publication No. 7-247702 [Patent Document 3] Japanese Patent Publication No. 2016-121453 [Overview of the project] [Problems that the invention aims to solve]

[0011] Therefore, the present invention was devised in view of the aforementioned problems, and its objective is to provide a method for dismantling overbridges, such as π-type rigid-frame bridges and portal-type rigid-frame bridges, that can be dismantled and removed without obstructing traffic beneath the overbridge. [Means for solving the problem]

[0012] The first invention relates to a method for dismantling an overbridge, which is a rigid frame bridge in which a substructure and a superstructure are rigidly connected, and is characterized by comprising: a bent assembly and installation step of assembling and installing a bent to support the cut superstructure so that it does not tip over at a position inside the center of gravity at the time of cutting the span; a scaffolding assembly and installation step of assembling and installing scaffolding to support the cut superstructure so that it does not fall; a counterweight installation step of loading and installing a counterweight at a position outside the center of gravity at the time of cutting so that the cut superstructure does not tip over; a span cutting step of cutting the superstructure at any position within the span; and a jacking-up step of jacking up the cut superstructure with vertical jacks, wherein the jacked-up superstructure is moved outward in the bridge axis direction using a feed device installed on the uppermost part of the bent and scaffolding for dismantling and removal.

[0013] The demolition method for an overbridge according to the second invention is characterized in that, in the first invention, the feeding device is an endless sliding device having an endless belt that can move forward and backward, and the method involves moving the jacked-up superstructure outward in the bridge axis direction using the endless sliding device installed at the uppermost stage of the bent and the scaffolding, and repeatedly performing a rail return process in which the load of the superstructure is temporarily supported by the bent and the scaffolding, and the endless sliding device is rotated in the reverse direction to move only the rails supporting the superstructure inward in the bridge axis direction, thereby moving the jacked-up superstructure outward in the bridge axis direction and demolition and removal.

[0014] The demolition method for an overbridge according to the third invention is characterized in that, in the first or second invention, the weight of the counterweight is adjusted after the superstructure has been cut. [Effects of the Invention]

[0015] According to the first to third inventions, the method can be applied to rigid-frame bridges such as π-type rigid-frame bridges and portal-type rigid-frame bridges, and the overpass can be dismantled and removed without obstructing traffic on roads, etc., beneath the overpass.

[0016] In particular, according to the second invention, the girder moving process and the rail return process are repeated to move the superstructure outward in the bridge axis direction for dismantling and removal, so that the rigid-frame bridge can be dismantled and removed more safely without obstructing traffic on roads, etc., under the overbridge.

[0017] In particular, according to the third invention, since the weight of the counterweight is adjusted after the superstructure is cut, the risk of the cut superstructure tipping over is further reduced, making it possible to dismantle and remove the rigid-frame bridge more safely. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a side view, seen in the road direction Y, showing the overbridge to be demolished using the overbridge demolition method according to this embodiment. [Figure 2] Figure 2 is a flowchart showing the steps of the demolition method for the overbridge according to this embodiment. [Figure 3] Figure 3 is a process diagram illustrating the bent assembly and installation process for the demolition method of the overbridge shown above. [Figure 4] Figure 4 is a process diagram illustrating the assembly and installation process of the support structure for the demolition method of the overbridge shown above. [Figure 5] Figure 5 is a process diagram illustrating the counterweight installation process for the demolition method of the overbridge shown above. [Figure 6] Figure 6 is a process diagram illustrating the span cutting process in the demolition method for the overbridge shown above. [Figure 7] Figure 7 is a process explanatory diagram showing the diagonal member joint cutting process of the demolition method of the overbridge described above. [Figure 8] Figure 8 is a process explanatory diagram showing the jacking-up process of the demolition method of the overbridge described above. [Figure 9] Figure 9 is a process explanatory diagram showing the first-digit movement process of the demolition method of the overbridge described above. [Figure 10] Figure 10 is a process explanatory diagram showing the rail splicing process of the demolition method of the overbridge described above. [Figure 11] Figure 11 is a process explanatory diagram showing the second-digit movement process of the demolition method of the overbridge described above. [Figure 12] Figure 12 is a process explanatory diagram showing the rail replacement process of the demolition method of the overbridge described above. [Figure 13] Figure 13 is a process explanatory diagram showing the third-digit movement process of the demolition method of the overbridge described above. [Figure 14] Figure 14 is a process explanatory diagram showing the vent demolition and removal process of the demolition method of the overbridge described above.

Embodiments for Carrying out the Invention

[0019] Hereinafter, an embodiment of the demolition method of the overbridge according to the present invention will be described in detail with reference to the drawings.

[0020] First, using FIG. 1, the overbridge B1 to be demolished by the demolition method of the overbridge according to the present embodiment will be briefly described. FIG. 1 is a side view seen in the road direction Y of the overbridge B1 to be demolished by the demolition method of the overbridge according to the present embodiment. The symbol X in the figure indicates the bridge axis direction X of the overbridge, and the symbol Y indicates the road direction Y of the lower road R1 orthogonal to the bridge axis direction X of the overbridge. The symbol Z indicates the vertical up-and-down direction Z along the vertical direction.

[0021] Overbridge B1 is a so-called π-type rigid frame bridge with diagonal members, comprising a substructure S1 that supports the bridge with diagonal members D1, and a superstructure S2 installed on the substructure S1 and having a main girder G1 that supports the traffic surface, wherein the diagonal members D1 of the substructure S1 and the main girder G1 of the superstructure S2 are rigidly connected without bearings.

[0022] The substructure S1 comprises a pair of left and right abutments A1 formed on the slope of the lower road R1, an abutment footing AF which is its foundation, and a pair of left and right abutments A2 formed at both outer ends of the main girder G1. The substructure S1 also comprises a diagonal member D1 which is a bridge pier (road-side diagonal member) projecting diagonally upward toward the road from the abutment A1, and a tie bar T1 which is a road shoulder-side diagonal member that connects the abutment A2 and the abutment A1 to prevent the gap between them from widening. Note that "outside" refers to the side away from the center CL of the overbridge B1 along the road direction Y, and conversely, "inside" refers to the side approaching the center CL of the bridge along the road direction Y (the same applies hereafter).

[0023] The superstructure S2 comprises a main girder G1, a deck slab (not shown) on which vehicles travel and pedestrians walk, and a wall parapet CP, which is a concrete wall installed on the side of the bridge to prevent falls. The main girder G1 has a span section G1a between the diagonal members D1 which are the bridge piers, and cantilever sections G1b are the parts that protrude outward from the bridge piers, corresponding to the "both ends of the horizontal bar" of the letter π. The presence of these cantilever sections G1b creates an effect (cantilever effect) that cancels out the bending moment acting on the span section G1a, allowing the thickness of the main girder G1 to be reduced.

[0024] Furthermore, Overbridge B1 is a pedestrian overpass that crosses over the lower road R1 via an overpass, allowing vehicles to travel on it and pedestrians to walk on it. The road that passes over Overbridge B1 is shown as through road R2 in the diagram.

[0025] [Demolition methods for overbridges] Next, using Figures 2 to 14, the demolition method for an overbridge according to an embodiment of the present invention will be explained by illustrating the case of demolishing the aforementioned overbridge B1. The demolition method for an overbridge according to this embodiment is a method in which, for example, the overbridge B1 is cut in the middle of the span to separate it from the diagonal members (diagonal members D1 and tie bars T1), and then moved to the outside of the abutment A1 for demolition and removal. Figure 2 is a flowchart showing each step of the demolition method for an overbridge according to this embodiment.

[0026] (Vent assembly and installation process) First, as shown in Figures 2 and 3, step 1 involves assembling and installing a bent 1 to support the overbridge B1 when it is cut in the subsequent span cutting process. This bent 1 is installed on the shoulder of one lane of the lower road R1, located inside the center of gravity at the time of cutting. The bent assembly and installation process is carried out by temporarily restricting traffic on one lane of the lower road R1 on the side where the bent 1 is installed. Figure 3 is a diagram illustrating the bent assembly and installation process for the overbridge demolition method according to this embodiment.

[0027] This bent 1 is a temporary support column made by combining temporary materials and steel materials, and an endless sliding device 2 is installed at the top of the bent 1. The endless sliding device 2 is a feeding device that serves as a fixed support point when sending out heavy structures such as bridge girders, and is a device that supports the structure with a low-friction endless belt and can continuously send it out in a way that allows it to move back and forth. The endless sliding device 2 is preferably an endless sliding device manufactured by Oxjack Co., Ltd., model number ES-25030A: vertical load capacity 2500kN, horizontal adjustment force 125kN x 2 units, or a driven endless sliding device, model number JES-25030: vertical load capacity 2500kN, horizontal adjustment force 200kN. However, the feeding device according to the present invention is not limited to an endless sliding device 2 having an endless belt, but may be any feeding device that can send out heavy structures such as bridge girders a certain distance in one direction.

[0028] Furthermore, a vertical jack 3 is provided in the middle section of this vent 1 for lifting the superstructure S2 in the subsequent jacking-up process. For this vertical jack 3, a hydraulic jack with a lifting capacity of 3000kN and a stroke of 230mm, such as the ACRL-30023 model manufactured by Oxjack Co., Ltd., is preferable.

[0029] (Scaffolding assembly and installation process) As shown in Figures 2 and 4, similar to the bent assembly and installation process, step 2 involves assembling and installing the support structure 4. This support structure 4 is a temporary structure that supports the bridge to prevent it from falling when the overbridge B1 is cut at any point within the span, such as the center of the span, during the span cutting process. As shown in Figure 4, this support structure 4 is assembled and installed on the slope of the abutment footing AF and the lower road R1. Figure 4 is a process diagram illustrating the support structure assembly and installation process of the overbridge demolition method according to this embodiment.

[0030] This support structure 4, like the bent 1, is a temporary support made by combining temporary materials and steel materials. An endless sliding device 2 is installed on the upper part of the support structure 4, and a vertical jack 3 is installed on the middle part.

[0031] The vent assembly and installation process and the shoring assembly and installation process may be carried out simultaneously, or the shoring assembly and installation process may be carried out before the vent assembly and installation process.

[0032] (Counterweight installation process) Next, as shown in Figures 2 and 5, in step 3, when the overbridge B1 is cut during the span cutting process, a counterweight installation process is performed in which a counterweight 5 is loaded and installed to prevent the cut bridge from toppling over. As shown in Figure 5, this counterweight 5 is loaded onto the overhang portion G1b of the main girder G1, which is outside the center of gravity position A at the time of cutting during the span cutting described later. Figure 5 is an explanatory diagram of the counterweight installation process of the overbridge demolition method according to this embodiment.

[0033] The weight of this counterweight 5 is set such that the center of gravity B after the counterweight 5 is placed on the protruding portion G1b is outside (on the slope side) of the line of the center position (central axis on the plane) of the abutment footing AF.

[0034] (Span cutting process) Next, as shown in Figures 2 and 6, step 4 involves cutting the superstructure S2 at the center of the span (the bridge's center CL in the figure), which is one of the positions within the span of the overbridge B1. Figure 6 is an explanatory diagram of the span cutting process in the overbridge demolition method according to this embodiment.

[0035] In the span cutting process according to this embodiment, the main girder G1 and the wall parapet CP are cut at the center of the span G1a, that is, at the midpoint between the diagonal members D1, which are the bridge piers (roadside diagonal members), using a cutting means such as a wall saw or a wire saw. At this time, since the center of gravity changes due to the cutting, the weight of the counterweight 5 is adjusted by adding or removing steel material from the counterweight 5. However, the position where the superstructure S2 is cut is not limited to the center of the span, but can be any position within the span.

[0036] (Diagonal member joint cutting process) Next, as shown in Figures 2 and 7, step 5 involves cutting the diagonal member joints, which are the joints connecting the superstructure S2 and substructure S1 of the overbridge B1. This process involves cutting the diagonal member joints, specifically the road-side diagonal member D1 and the shoulder-side diagonal member tie bars T1. Figure 7 is an explanatory diagram illustrating the diagonal member joint cutting process in the overbridge demolition method according to this embodiment.

[0037] In the diagonal member joint cutting process, the diagonal members D1 and tie bars T1 are cut using cutting tools such as wall saws or wire saws to separate the main girder G1 from the substructure S1. At this time, the center of gravity changes due to the cutting, so the weight of the counterweight 5 is adjusted by adding or removing steel material from the counterweight 5.

[0038] In this process, if the concrete of abutment A2 and the through road R2 are connected, or if expansion joints or the like are installed, it is preferable to cut them off in order to facilitate lifting in the subsequent jack-up process.

[0039] (Jack-up process) Next, as shown in Figures 2 and 8, step 6 involves a jacking-up process in which the main girder G1 of the overbridge B1 (specifically, the superstructure S2 and the abutment A2 connected to the outer end of the superstructure S2), which was separated in the span cutting process and the diagonal member joint cutting process, is jacked up using the aforementioned vertical jacks 3. The height to which the girder G1 is jacked up in the jacking-up process is set to a predetermined height that is greater than or equal to the girder height of the main girder G1.

[0040] If the height to be jacked up exceeds the lifting height of vertical jack 3, the jacking process and the raising process using steel materials are repeated until a predetermined height equal to or greater than the girder height is reached.

[0041] Additionally, an endless sliding device 2 will be added to the empty space beneath abutment A2 of the jacked-up overbridge B1. This is to allow for the insertion of additional rails 6' in a later step.

[0042] (First digit movement process) Next, as shown in Figures 2 and 9, step 7 involves moving the main girder G1 (superstructure S2 and abutment A2), which was jacked up and lifted in the jacking-up process, outward in the bridge axis direction X indicated by the arrows in the figure, using the endless sliding device 2. Figure 9 is an explanatory diagram of the process showing the first girder movement process of the overbridge demolition method according to this embodiment.

[0043] In the first girder moving process, first, the support steel around the endless sliding device 2 at the top of the bent 1 and scaffolding 4 is removed. Then, the endless sliding device 2 is driven to move the main girder G1 (superstructure S2 and abutment A2), which was cut at the center of the span on the endless sliding device 2, outwards in the direction of the bridge axis X until the inner end of the rail 6 installed at the top of the scaffolding 4 reaches the endless sliding device 2 installed on the inside in the direction of the bridge axis X on the scaffolding 4.

[0044] (Rail extension process) Next, as shown in Figures 2 and 10, in step 8, steel materials are inserted between the superstructure S2 and abutment A2, which have undergone the first girder movement process, and the rail 6, and these loads are temporarily supported by the bent 1 and shoring 4. The endless sliding device 2 is then rotated in the reverse direction to insert the additional rail 6' in the bridge axis direction X, and the rail 6 and the additional rail 6' are bolted together via a splice plate in a rail splicing process. In the rail splicing process, the endless sliding device 2 is used to push the rail 6 and the additional rail 6' in the bridge axis direction X until the splice plate, which is the joint between the rail 6 and the additional rail 6', approaches the endless sliding device 2 installed on the outside of the shoring 4. Figure 10 is a process diagram illustrating the rail splicing process of the overbridge demolition method according to this embodiment.

[0045] Furthermore, as shown in Figure 10, it is preferable to excavate the road connected to the overbridge B1 and add multiple endless sliding devices 2 before performing the rail extension process. This is because the added endless sliding devices 2 make it easier to insert the additional rails 6' horizontally.

[0046] (Second digit shift process) Next, as shown in Figures 2 and 11, step 9 involves moving the main girder G1 (superstructure S2 and abutment A2) outward in the bridge axis direction X, as indicated by the arrows in the figures, using the endless sliding device 2. Figure 11 is a process diagram illustrating the second girder movement step of the overbridge demolition method according to this embodiment.

[0047] First, in the second girder movement process, adjustment materials are inserted between the main girder G1 (superstructure S2 and abutment A2), which was temporarily supported by bent 1 and shoring 4 in the rail extension process, and rail 6 and additional rail 6', thereby transferring the load of the main girder G1 (superstructure S2 and abutment A2) to rail 6 and additional rail 6'.

[0048] Subsequently, in the second girder movement process, the endless sliding device 2 is driven to move the main girder G1 (superstructure S2 and abutment A2) outward in the bridge axis direction X until the inner end of the rail 6 joined in the rail splicing process reaches the endless sliding device 2 installed on the support structure 4 on the inside in the bridge axis direction X.

[0049] (Rail return process) Next, as shown in Figures 2 and 12, in step 10, steel materials are placed between the superstructure S2 and abutment A2, which have undergone the second girder movement process, and the rail 6, and these loads are temporarily supported by the bent 1 and scaffolding 4. The endless sliding device 2 is then rotated in the reverse direction to perform a rail return process in which only the rail 6 and additional rail 6' are moved inward in the bridge axis direction X. In the rail return process, the endless sliding device 2 is used to push the rail 6 and additional rail 6' inward in the bridge axis direction X until the splice plate, which is the joint, approaches the endless sliding device 2 installed on the outside of the scaffolding 4. Figure 12 is a process explanatory diagram showing the rail return process of the overbridge demolition method according to this embodiment.

[0050] (Third digit shifting process) Next, as shown in Figures 2 and 13, step 11 involves moving the main girder G1 (superstructure S2 and abutment A2) outward in the bridge axis direction X, as indicated by the arrows in the figures, using the endless sliding device 2. Figure 13 is a diagram illustrating the third girder movement process in the overbridge demolition method according to this embodiment.

[0051] In the third girder movement process, similar to the second girder movement process, adjustment members are inserted between the main girder G1 (superstructure S2 and abutment A2), which had been temporarily supported by bent 1 and shoring 4 during the rail return process, and rail 6 and additional rail 6', thereby transferring the load of the main girder G1 (superstructure S2 and abutment A2) to rail 6 and additional rail 6'.

[0052] Subsequently, in the third girder movement process, the endless sliding device 2 is driven to move the main girder G1 (superstructure S2 and abutment A2) outward in the bridge axis direction X until the inner ends of the rail 6 and additional rail 6', which were moved inward in the bridge axis direction X during the rail return process, reach the endless sliding device 2 installed on the support structure 4 inward in the bridge axis direction X.

[0053] (Repeat of rail return process ~ third digit movement process) Then, as shown in Figure 2, the aforementioned rail return process and third girder movement process are repeated until the inner end of the main girder G1 (superstructure S2 and abutment A2), which has been cut in the middle of the span, reaches above the scaffolding 4 installed above the abutment A1 on the slope of the lower road R1. This is because once the inner end of the main girder G1 has gone beyond the abutment A1 on the lower road R1 and reached the area where the scaffolding 4 is installed, the work of cutting or chipping away at the main girder G1 to dismantle and remove it poses very little risk of obstructing traffic on the lower road R1.

[0054] (Vent dismantling and removal process) Finally, as shown in Figures 2 and 14, by repeating the rail return process and the third girder movement process, when the inner end of the main girder G1 (superstructure S2 and abutment A2) reaches the area where the support structure 4 above abutment A1 is installed, step 12 is performed, which is a bent dismantling and removal process in which the bent 1 is dismantled and removed. Once the bent dismantling and removal process is completed, the main girder G1 is cut, dismantled and removed in an area that does not affect traffic on the lower road R1, thereby completing the dismantling and removal work of the overbridge dismantling method according to this embodiment. Figure 14 is a process explanatory diagram showing the bent dismantling and removal process of the overbridge dismantling method according to this embodiment.

[0055] According to the demolition method for overbridges of this embodiment described above, overbridges of rigid-frame bridges such as π-type rigid-frame bridges and portal-type rigid-frame bridges can be demolished and removed without obstructing traffic beneath the overbridge.

[0056] Furthermore, according to the overbridge demolition method of this embodiment, the girder movement process and the rail return process are repeated to gradually move the superstructure outward in the bridge axis direction and dismantle and remove it. This makes it possible to dismantle and remove the rigid-frame bridge more safely without obstructing traffic on roads, etc., beneath the overbridge.

[0057] Furthermore, according to the overbridge demolition method of this embodiment, the weight of the counterweight is adjusted after the superstructure is cut in the span cutting process and the diagonal member joint cutting process, thereby reducing the risk of the cut superstructure toppling over and allowing for safer demolition and removal of the rigid-frame bridge.

[0058] Although the demolition method for an overbridge according to an embodiment of the present invention has been described in detail above, the embodiments described above or illustrated are merely examples of specific embodiments implemented in carrying out the present invention. Therefore, the technical scope of the present invention should not be interpreted as being limited by these embodiments.

[0059] In particular, while a π-type rigid frame bridge with diagonal members was used as an example of the overbridge B1 to be demolished in this embodiment, the method is also applicable to other types of rigid frame bridges, such as portal rigid frame bridges. Furthermore, the overbridge B1 is not limited to road bridges or railway bridges, but also includes overbridges that are constructed to span above a line of traffic, such as highways, railways, or production lines in factories, without obstructing the passage of such traffic. [Explanation of symbols]

[0060] 1: Vent 2: Endless sliding device 3: Vertical jack 4: Shoring 5: Counterweight 6: Rail 6': Additional rails B1: Overbridge S1: Substructure A1: Abbat AF: Abbutt footing A2: Bridge abutment D1: Diagonal material (road side diagonal material) T1: Tie bar (road shoulder diagonal brace) S2: Superstructure G1: Main girder G1a: span section G1b: Overhang

Claims

1. A method for dismantling and removing an overbridge consisting of a rigid frame bridge with a lower structure and a superstructure rigidly connected, A bent assembly and installation process involves assembling and installing a bent at a position inside the center of gravity at the time of cutting the span, to support the cut upper structure and prevent it from tipping over. A scaffolding assembly and installation process involves assembling and installing scaffolding to support the cut superstructure so that it does not fall, A counterweight installation step involves placing a counterweight at a position outside the center of gravity at the time of cutting to prevent the cut upper structure from tipping over. A span cutting step in which the superstructure is cut at any position within the span, The device includes a jacking-up step in which the cut upper structure is jacked up using a vertical jack, The superstructure, which has been jacked up using a feeder installed at the top of the bent and the support structure, is moved outward in the direction of the bridge axis and dismantled and removed. A demolition method for overbridges characterized by the following:

2. The aforementioned feeding device is an endless sliding device having an endless belt that can move back and forth, The process involves moving the jacked-up superstructure outward in the bridge axis direction using the endless sliding device installed on the uppermost part of the bent and the scaffolding, and then repeatedly performing a rail return process in which the load of the superstructure is temporarily supported by the bent and the scaffolding, and the endless sliding device is rotated in the reverse direction to move only the rails supporting the superstructure inward in the bridge axis direction, thereby moving the jacked-up superstructure outward in the bridge axis direction and dismantling and removing it. The method for dismantling an overbridge according to claim 1, characterized by the above.

3. After cutting the superstructure, adjust the weight of the counterweight. A method for dismantling an overbridge according to claim 1 or 2, characterized by the above.

Images