A method for dismantling an arch bridge using cables without towers

Abstract

The present invention discloses a method for dismantling an arch bridge without tower cables. First, the arch auxiliary structure, bridge deck, and bent frame are dismantled according to the principle of first up and then down, with overall symmetry in the longitudinal and transverse directions. Second, temporary cables are installed on the arch ribs and tightened. The top, bottom, and arch ribs of the arch ribs are then dismantled. After the top and bottom plates are removed, the temporary cables are adjusted again to tighten the cables. The arch ribs are then symmetrically removed in sequence using a floating crane. The temporary cables are released to complete the dismantling of the main arch. Finally, the main piers are cut into small pieces and hoisted for removal. Finally, the above-water piers are dismantled. The above-water portion is cut and hoisted for removal, while the underwater portion is directly cracked and cleaned. The present invention has the characteristics of a simple dismantling method, safety and reliability, low cost, and environmental friendliness.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge engineering, and more particularly to a method for dismantling an arch bridge without tower cables. Background Art

[0002] With the development of my country's economy, the number of vehicles has increased rapidly, and overweight and overloaded vehicles have become more and more frequent, causing more and more serious damage to bridges. Many bridges have been demolished and rebuilt. Existing methods for dismantling arch bridges are mostly to set up supports under the arch and cut and dismantle them, or to chisel and crack the sides of the bridge, or to demolish them by blasting. The arch bridge involved in this application project has been assessed as a dangerous bridge due to the impact of upstream flood discharge and water flow, which has caused the arch ribs to shift, affecting the safety of the bridge structure. The main bridge and approach bridge need to be completely dismantled and rebuilt. The main difficulties in the demolition process are as follows: risk of arch rib collapse; tight construction period; high environmental protection requirements: water source protection, dust control, soil and water conservation. Therefore, it is necessary to study a safer, more environmentally friendly, economical and faster method for dismantling arch bridges. Summary of the Invention

[0003] An object of the present invention is to provide a method for dismantling an arch bridge without tower cables, which has the characteristics of being simple, safe, reliable, low-cost, and environmentally friendly.

[0004] In order to achieve these purposes and other advantages according to the present invention, a method for dismantling an arch bridge without using tower cables is provided, which includes dismantling the main bridge and the approach bridge and performing simultaneous construction. It does not require the construction of tall towers or under-arch supports, and has the advantages of simple and convenient construction, low cost and short time.

[0005] The main arch bridge was dismantled by first dismantling the arch's auxiliary structures, bridge decks, and bent frames in accordance with the principle of "up first, down last," with overall symmetry in both the longitudinal and transverse directions. Temporary cables were then installed and tightened. The top, bottom, and arch rib plates of the arch ribs were then dismantled. After the top and bottom plates were removed, the temporary cables were adjusted and tightened again. The arch ribs were then removed symmetrically and in sequence using a floating crane. The temporary cables were then released, completing the main arch dismantling.

[0006] Finally, the main pier is cut into small pieces and then hoisted and removed. Finally, the water pier is removed. The water part is cut and hoisted and removed, and the underwater part is directly cracked and cleaned.

[0007] Preferably, the temporary cable includes U-shaped steel bars, basket bolts and steel wire ropes. Several U-shaped steel bars are planted at intervals on the arch rib back and the pier abutment. Steel wire ropes are sequentially passed through the U-shaped steel bars between the arch rib back and the pier abutment, and basket bolts are set in the middle of the steel wire ropes for tightening.

[0008] Preferably, the arch ribs are removed by:

[0009] First, after the arch structure is dismantled, temporary cables are installed. Several U-shaped steel bars are planted at intervals on the arch ribs and pier abutments, with a planting depth of no less than 25 cm. After the rebar glue cures, steel wire ropes are threaded through the arch ribs one by one. Turnbuckles are used to tighten the ropes in between, and the tension of each wire rope is checked with a torque wrench. Finally, the wire ropes are used to securely connect the turnbuckles at both ends.

[0010] Secondly, the arch top plate and arch bottom plate are cut and removed in sequence by using floating crane pre-lifting. The removal process starts from the arch top and moves towards the arch foot in a symmetrical manner.

[0011] Again, adjust the temporary cable tension again, use the floating crane to pre-lift the arch ribs, cut off the middle partition in the middle of the arch ribs, and then cut the two ends of the arch ribs. Then, move the floating crane back and lift the removed arch ribs.

[0012] The arch ribs on both sides are pre-lifted with a floating crane, the cables are released, the arch feet are cut off, and the demolition is completed;

[0013] Finally, remove the arch ribs symmetrically in turn according to the above method, and remove the temporary cables.

[0014] Preferably, when removing the arch ribs, the middle arch ribs in the middle section are removed first.

[0015] Preferably, the two arches correspond to one floating crane respectively, the front side of the floating crane is anchored to the middle pier and the adjacent bridge pier by two crossed front anchor ropes, and the rear side of the floating crane is anchored to a pair of anchor blocks by two crossed rear anchor ropes, and the pair of anchor blocks are fixed to a pair of shore sides respectively.

[0016] Preferably, when cutting the bridge deck, geotextile tapes matching the arch ring are set on both sides of the arch ring, and the sewage from the bridge deck cutting is led to the arch foot and then collected and treated in a water tank; when cutting the arch bottom plate, arch top plate, and arch ribs, the cutting machine is placed on the barge, and geotextile tapes are also tied on both sides of the cutting chain. The sewage will be drained to the barge under the bridge, and discharged after sedimentation.

[0017] The present invention has at least the following beneficial effects:

[0018] 1. The arch bridge dismantling method of the present invention utilizes the original bridge structure and adopts a temporary cable-assisted method, which can reduce the construction cost of the tower, shorten the construction period, and is safe and reliable.

[0019] 2. The arch bridge demolition method of the present invention constructs the main bridge and the approach bridge at the same time, which can shorten the construction period, improve construction efficiency and reduce construction costs; the demolition sequence is completely in the reverse order of the construction when the original bridge was newly built, and the structure is safe and reliable during the demolition process.

[0020] 3. The arch bridge demolition method of the present invention adopts the principle of first up and then down, and overall symmetry in the longitudinal and transverse directions for demolition. At the same time, by applying temporary buckle assistance, the demolition process is safe and reliable, reducing or even completely avoiding the risk of collapse during the arch bridge demolition process.

[0021] Other advantages, objectives and features of the present invention will be reflected in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the overall structure of the arch bridge after the temporary cable construction of the present invention;

[0023] Figure 2 A partial enlarged view of the temporary buckle of the present invention;

[0024] Figure 3 This is the arch rib hoisting floating crane arrangement diagram of the present invention;

[0025] Figure 4 This is a schematic diagram of the geotextile tape layout of the present invention.

[0026] Description of reference numerals:

[0027] 1. U-shaped steel bar, 2. Turnbuckle, 3. Steel wire rope, 4. Arch rib, 5. Pier abutment, 6. Floating crane, 7. Front anchor rope, 8. Rear anchor rope, 9. Anchor block, 10. Intermediate pier, 11. Pier, 12. Geotextile tape, 13. Water tank, 14. Barge. DETAILED DESCRIPTION

[0028] The present invention will be described in further detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0029] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "horizontal", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0030] The construction project corresponding to this application is a catenary-type single-box arch bridge with a clear span of 80m and a 2-hole span. The arch-rise ratio is 1:9, the arch axis coefficient is 1.543, the piers are built with gravity expansion foundations, and the main arch ring is constructed with a cable-suspended cantilever assembly process. The arch rib width is 5.7m, and the concrete volume of a single arch rib is approximately 235m. 3 The bridge deck in the hollow section is a longitudinal bridge deck with a length of 4.6m, the side deck installation weight is 2.56t, and the middle deck installation weight is 2.43t. The arch section is a transverse bridge deck with a length of 5.7m and a maximum installation weight of 4t. The transverse bridge deck is connected to the side wall with anchor bars.

[0031] The approach bridge is a hollow slab simply supported beam bridge with a span of 13m, a beam height of 1m, a side plate weight of 24t, and a middle plate weight of 13t.

[0032] The main difficulties in the demolition process mentioned in the background technology of this application are as follows: risk of arch rib collapse; tight construction period; high environmental protection requirements: water source protection, dust control, soil and water conservation; the solutions are: strictly follow the principle of symmetrical demolition of arch ribs, horizontal and vertical symmetry, when dismantling the arch pieces, pre-lift the floating crane and monitor the process; the main bridge and approach bridge are constructed at the same time; and the local water and soil are not damaged.

[0033] The present invention provides a method for dismantling an arch bridge without tower cables, which includes dismantling a main bridge and an approach bridge, and the dismantling of the main bridge and the approach bridge are carried out simultaneously.

[0034] The overall demolition order of the main bridge: according to the principle of up-first and down-latitudinal and transverse overall symmetry, the arch bridge deck - the arch frame - the arch rib - the pier; the arch bridge deck: demolished symmetrically in the transverse and longitudinal directions; the arch rib: first cut and remove the top plate and the bottom plate, leaving only two rib plates, the single rib plate is pre-lifted with a floating crane, the partition is cut off, the arch rib is cut off from the arch seat, and then hoisted to the shore, cut into small pieces, and then transported to the back field and removed with a blasting machine.

[0035] Right pier on the shore: First cut into small pieces, lowered to the ground with a 180t floating crane, chiseled out, and cracked;

[0036] In-water pier: The above-water part is removed by cutting, transported to a temporary wharf by a floating crane, and then broken and transported to a designated location for breaking; the underwater part is broken with a water excavator and cleaned.

[0037] Left pier on the shore: the upper 5m is chiseled out by blasting machine, the lower part is chiseled out by water excavator, and the slag is cleared.

[0038] The middle pier is located in the center of the river channel. The upper portion of the arch seat was cut horizontally three times, with a lifting weight of approximately 60 tons. The middle arch seat was divided into four sections, with one vertical cut and one horizontal cut in the middle, each weighing 100 tons. The underwater section was removed using a water excavator until it was level with the original riverbed, and then the waste residue was salvaged using a dredger.

[0039] The specific demolition of the bridge deck of the main bridge is as follows: longitudinally, the bridge decks on each arch of the arch bridge are demolished symmetrically from the middle to both sides; horizontally, the two sides are demolished first and then the middle.

[0040] In the temporary detent method, such as Figure 1 and Figure 2 As shown, the temporary cable tie consists of U-shaped steel bars 1, turnbuckles 2, and steel wire rope 3. Several U-shaped steel bars 1 are planted at intervals on the arch rib 4 and the pier abutment 5. Steel wire ropes are threaded through the U-shaped bars between the arch rib and the pier abutment, and turnbuckles are placed in between to tighten the wire ropes. Turnbuckle bolt tension testing: A torque wrench is used to test the tension to ensure that the tension matches the design. Steel wire rope is then used to connect the two sides of the turnbuckle to prevent failure.

[0041] The removal of the arch ribs is as follows:

[0042] First, the arch top and arch bottom plates are removed in sequence by pre-lifting with a floating crane. The removal process starts from the arch top and moves towards the arch foot in a symmetrical manner.

[0043] Secondly, temporary cables are constructed. Several U-shaped steel bars are planted at intervals on the arch ribs and pier abutments, with a planting depth of no less than 25 cm. After the anchoring glue has cured, the steel wire ropes are threaded through them one by one. Turnbuckles are used to tighten the ropes in between. A torque wrench is used to check the tension of each wire rope. Finally, the wire ropes are used to lock the two ends of the turnbuckle bolts tightly.

[0044] Temporary cable fastenings were installed on the piers. These cables consisted of steel wire rope and turnbuckles. First, φ11mm U-shaped rebar was planted at least 25cm deep on the arch ribs and piers. After the anchoring adhesive cured, a φ13cm steel wire rope was threaded through the piers. Tightened with a φ28 turnbuckle in the middle, the tension was checked with a torque wrench, and the ends were secured with steel wire rope clamps. The two arches were arranged symmetrically, both horizontally and longitudinally. Calculations indicate that the cable load is approximately 5.4t, with a safety factor of at least 3.

[0045] Secondly, the arch top plate and arch bottom plate are cut and removed in sequence by using floating crane to pre-lift. The removal process starts from the arch top and moves towards the arch foot in a symmetrical manner.

[0046] Again, adjust the temporary cable tension again, use the floating crane to pre-lift the arch ribs, cut off the middle partition in the middle of the arch ribs, and then cut the two ends of the arch ribs. Then, move the floating crane back and lift the removed arch ribs.

[0047] Finally, remove the arch ribs symmetrically in turn according to the above method, and remove the temporary cables.

[0048] In the above technical solution, based on the original new construction process, the principle of dismantling in reverse order is followed to ensure the stability of the arch ribs. The dismantling sequence is as follows: Use a floating crane to pre-lift, cut and remove the arch top plate, starting from the arch top and working towards the arch foot; the two arches are dismantled symmetrically; the single-section top plate weighs 10 tons and is lifted ashore by a 50-ton truck crane and transported to a crushing site for dismantling; Use a floating crane to pre-lift, cut and remove the arch bottom plate, starting from the arch top and working towards the arch foot; the two arches are dismantled symmetrically, leaving a middle partition plate; the single-section bottom plate weighs 7 tons and is lifted ashore by a 50-ton truck crane and transported to a crushing site for dismantling;

[0049] A 70t and a 180t floating crane (using the 70t model) were used to pre-lift the arch ribs on one side of the two arches. The 40m of diaphragms in the middle of the arch ribs were cut. The ribs were then cut sequentially at 13m at the arch foot and at the arch crown. The floating crane was then withdrawn and hoisted to the shore. The ribs were then cut into small sections using a rope saw and loaded onto a transport vehicle for transport to a designated crushing site. The cantilevered arch ribs were then removed by pre-lifting the floating crane again, cutting the diaphragms at the cantilevered sections. The arch ribs were then cut and removed. 13m of the arch foot section was left for each arch rib, resulting in a 40m section and a weight of 2.2*40=88t. A 70t floating crane was used to meet these requirements.

[0050] like Figure 3 As shown, the two arches correspond to a floating crane 6 respectively. The front side of the floating crane is anchored to the middle pier 10 and the adjacent bridge pier 11 through two crossed front anchor ropes 7, and the rear side of the floating crane is anchored to a pair of anchor blocks 9 through two crossed rear anchor ropes 8. The pair of anchor blocks 9 are fixedly set on a pair of shore sides.

[0051] like Figure 4 As shown, when the bridge deck is cut, geotextile tapes 12 matching the arch ring are set on both sides of the arch ring to lead the sewage from the bridge deck cutting to the arch foot and then collected and treated in a water tank 13; when cutting the arch bottom plate, arch top plate, and arch ribs, the cutting machine is placed on a barge 14, and geotextile tapes 12 are also tied on both sides of the cutting chain. The sewage will be drained to the barge 14 under the bridge and discharged after sedimentation.

[0052] The water used in the main bridge construction will have a certain impact on water quality. Wastewater from the bridge deck excavation will flow onto the arch rings. Geotextile tape will be installed on both sides of the arch rings to divert the wastewater to the arch foot, where it will be collected and treated in water tanks. When cutting the base plate, roof plate, and arch ribs, the cutter will be placed on a boat with geotextile tape tied to both sides of the chain. Wastewater will flow to the boat below the bridge, where it will settle and then be discharged.

[0053] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for dismantling an arch bridge without tower cables, characterized in that: The demolition includes the demolition of the main bridge and the approach bridge, which will be carried out simultaneously. The main arch bridge to be demolished is a two-span single-box arch bridge with two arch rib structures. The arch rib structure is a single-box structure consisting of an arch top plate, an arch bottom plate and arch ribs on both sides. The bridge piers and abutments are gravity-type expanded foundations. The main arch bridge was dismantled by first dismantling the arch auxiliary structures, bridge deck and bent frames in the principle of upper-first and lower-last, with overall longitudinal and transverse symmetry; then installing temporary cables and tightening them; Then, the arch rib's crown plate, arch base plate, and arch rib segments are removed. After the arch crown plate and arch base plate are removed, the temporary cables are adjusted again and tightened. Using a floating crane, the arch rib segments are removed symmetrically and in sequence, and the temporary cables are released to complete the main arch removal. The temporary cables consist of steel wire ropes installed between the arch rib and the pier abutment. Finally, the main pier is cut into small pieces and then hoisted and removed. Finally, the water pier is removed. The water part is cut and hoisted and removed, and the underwater part is directly cracked and cleaned.

2. The method for dismantling an arch bridge without tower cables as claimed in claim 1, characterized in that: The specific demolition of the bridge deck of the main bridge is as follows: longitudinally, the bridge decks on each arch of the arch bridge are demolished symmetrically from the middle to both sides; horizontally, the two sides are demolished first and then the middle.

3. The method for dismantling an arch bridge without tower cables as claimed in claim 1, characterized in that: Temporary cables include U-shaped steel bars, basket bolts and steel wire ropes. Several U-shaped steel bars are planted at intervals on the arch rib back and the pier abutment. Steel wire ropes are passed through the U-shaped steel bars between the arch rib back and the pier abutment in sequence, and basket bolts are set in the middle of the steel wire ropes for tightening.

4. The method for dismantling an arch bridge without tower cables as claimed in claim 3, characterized in that: The removal of the arch ribs is as follows: First, the arch top and arch bottom plates are removed in sequence by pre-lifting with a floating crane. The removal process starts from the arch top and moves towards the arch foot in a symmetrical manner. Secondly, temporary cables are constructed. Several U-shaped steel bars are planted at intervals on the arch ribs and pier abutments, with a planting depth of no less than 25 cm. After the anchoring glue has cured, the steel wire ropes are threaded through them one by one. Turnbuckles are used to tighten the ropes in between. A torque wrench is used to check the tension of each wire rope. Finally, the wire ropes are used to lock the two ends of the turnbuckle bolts tightly. Next, use the floating crane to pre-lift the arch ribs and cut off the middle partition in the middle of the arch ribs. Then cut both ends of the arch ribs. Then, move the floating crane back and lift and remove the middle section of the arch ribs. The arch ribs on both sides are pre-lifted with a floating crane, the cables are released, the arch feet are cut off, and the demolition is completed; Finally, remove the arch ribs symmetrically in turn according to the above method, and remove the temporary cables.

5. The method for dismantling an arch bridge without tower cables as claimed in claim 4, characterized in that: The two arch ribs correspond to one floating crane respectively. The front side of the floating crane is anchored to the middle pier and the adjacent bridge pier through two crossed front anchor ropes, and the rear side of the floating crane is anchored to a pair of anchor blocks through two crossed rear anchor ropes. The pair of anchor blocks are fixed to a pair of shore sides respectively.

6. The method for dismantling an arch bridge without tower cables as claimed in claim 1, characterized in that: When cutting the bridge deck, geotextile tapes matching the arch ribs are set on both sides of the arch ribs to lead the sewage from the bridge deck cutting to the arch foot and then collected and treated in a water tank; when cutting the arch bottom plate, arch top plate, and arch ribs, the cutting machine is placed on the barge, and geotextile tapes are also tied on both sides of the cutting chain to lead the sewage to the barge under the bridge, where it is discharged after sedimentation.

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