CN114045758A

CN114045758A - Construction method for dismantling old bridge of precast beam

Info

Publication number: CN114045758A
Application number: CN202111354496.9A
Authority: CN
Inventors: 林文; 王振琦; 刘征宇; 潘邦群; 邹沐恩; 曹杨; 周妤莲; 李家柱; 苏强
Original assignee: Guangxi Road and Bridge Engineering Group Co Ltd
Current assignee: Guangxi Road and Bridge Engineering Group Co Ltd
Priority date: 2021-11-16
Filing date: 2021-11-16
Publication date: 2022-02-15

Abstract

The invention relates to the field of bridge dismantling, in particular to a construction method for dismantling an old bridge of a precast beam, which comprises the following steps: s1: traffic control; s2: setting anti-collision isolation measures; s3: dismantling the anti-collision wall; s4, beam body splitting: according to the old bridge drawing, on wing plates on two sides of a web plate at 1/4 and 3/4 in the length direction of each beam, drilling hoisting holes with the diameter not less than 150mm along a wet joint by a drilling machine, cutting a cutting line along the center line of the wet joint, and dividing a beam body along the cutting line to form independent beam sections; s5: hanging and moving the beam section: the old bridge sections are hoisted and moved span by span until the half width of the full bridge is removed; s6: adjusting traffic control, repeating S2-S5, and completing the dismantling of the remaining half-width old bridge plate span by span; s7: dismantling the capping beam; s8: and (5) dismantling the pier stud. The method is characterized in that a hoisting hole is pre-drilled according to the structural characteristics of the old bridge of the precast beam under the condition of not interrupting main line traffic, after scribing, the steps of segmenting, hoisting and crushing piece by piece are carried out, and the old bridge of the existing precast beam is safely and quickly dismantled after the steps of dismantling piece by piece, hoisting and crushing span by span are completed.

Description

Construction method for dismantling old bridge of precast beam

Technical Field

The invention relates to the field of bridge dismantling, in particular to a construction method for dismantling an old bridge of a precast beam.

Background

With the continuous development of urban economy, the existing highway has a span which can not meet the traffic demand gradually, and the reconstruction and expansion projects on the existing highway are increased gradually, for example, the reconstruction and expansion project for replacing a bidirectional four lane with a bidirectional eight lane, because the span of the highway is increased, the existing bridge arranged on the highway can not meet the demand, so that the old bridge on a main line is generally required to be dismantled in the reconstruction and expansion project, and different types of old bridges have different structures, if the same dismantling scheme is adopted, the dismantling efficiency is greatly influenced, the potential safety hazard is brought, and the normal traffic of the highway is influenced.

The in-process of demolising the old bridge of thread if seal the thread traffic, will bring very big economic loss, so, at the old bridge of thread demolish the in-process, the traffic can not be interrupted, leads to demolish the condition limited, to the old bridge of precast beam, the beam slab that needs to demolish is in large quantity, and the construction degree of difficulty is great, belongs to dangerous great engineering, how under the circumstances of guaranteeing normal traffic, safely, demolish current old bridge of precast beam has become the technical problem who waits to solve urgently fast.

Disclosure of Invention

The invention aims to: aiming at the problems in the background art, a construction method for dismantling an old bridge of a precast beam is provided.

In order to achieve the purpose, the invention adopts the technical scheme that:

a construction method for dismantling an old bridge of a precast beam comprises the following steps:

s1: traffic control: closing half-width passing or width-splicing section passing;

s2: setting anti-collision isolation measures: arranging anti-collision isolation measures between the construction area and the traffic area, wherein the anti-collision isolation measures comprise a safety spacing distance not less than 1m and at least one span anti-collision isolation fence;

s3: dismantling the anti-collision wall: the method comprises the following steps of cutting an anti-collision wall in sections by using a wire saw, dividing the anti-collision wall into sections at intervals of 4m, arranging at least two hoisting holes with the diameter not less than 100mm in each section, and hoisting and crushing the anti-collision wall in a piece-by-piece manner;

s4, beam body splitting: according to the old bridge drawing, on wing plates on two sides of a web plate at 1/4 and 3/4 in the length direction of each beam, drilling hoisting holes with the diameter not less than 150mm along a wet joint by a drilling machine, cutting a cutting line along the center line of the wet joint, and dividing a beam body along the cutting line to form independent beam sections;

s5: hanging and moving the beam section: at least one truck crane supporting leg is arranged on the upper span bridge floor of the old bridge or the ground beside the old bridge, a single beam section is bound through a steel wire rope, and the old bridge section is cut and hung one by one in a span-by-span manner until the half width of the full bridge is removed;

s6: adjusting traffic control, repeating S2-S5, and completing the dismantling of the remaining half-width old bridge plate span by span;

s7: dismantling the capping beam: assembling a bent cap dismantling platform on one side of the pier stud close to the ground, lifting the bent cap dismantling platform to a proper height of the top of the pier stud for fixing, and cutting the bent cap in sections on the bent cap dismantling platform, and hanging the bent cap section by section for crushing;

s8: dismantling the pier stud: and (3) building a coated pier stud dismantling platform on the pier stud, cutting the pier stud in blocks on the pier stud dismantling platform, and hanging and crushing the pier stud block by block.

The construction method for dismantling the old bridge of the precast beam realizes safe and quick dismantling of the existing old bridge of the precast beam under the condition of not interrupting main line traffic, wherein a traffic control measure of half-width traffic or width splicing section traffic is adopted, and an anti-collision isolation measure is matched, so that traffic is not interrupted and driving safety is ensured in the process of dismantling the old bridge.

As a preferred embodiment of the present invention, in the case of the cap beam of the column pier, S7 specifically includes the following steps:

s7.1: the cover beam is scribed and segmented into a cantilever part, a middle part of two pier columns and a pier top;

s7.2: after the cantilever part is tightly hung through a crane steel wire rope, cutting and separating the cantilever part, and then hoisting and crushing;

s7.3: binding type hoisting construction is carried out on the space between the two pier studs, the space is hoisted tightly by a crane, the space is cut longitudinally and separated into at least three sections, and each section is hoisted and crushed respectively;

s7.4: and respectively cutting the side surface and the top surface of the top of the pier, drilling the top surface of the bent cap after the bent cap stirrup is cut off, burying an expanding agent, and chiseling by adopting manpower after the concrete cracks. The cover beam is fast and safe in the dismantling process, and less broken stones are produced.

In the preferred embodiment of the present invention, in S7.2, on both side surfaces of the cantilever part along the width of the canopy beam, a through hole with a diameter of 35mm is drilled by a pneumatic drill at a position where the height 1/3 is separated from both end surfaces 1/4 of the cantilever part on the basis of the canopy beam, a threaded rod with a diameter of 32mm which is not shorter than 50cm is inserted into the through hole, at least 30cm is exposed, and when the cantilever part is bound by a crane wire rope, the threaded rod is positioned between two adjacent hoisting points. The threaded rod can limit the displacement of the steel wire rope, the safety of the cantilever part in the hanging-off process is ensured, and the cantilever part is quickly and safely dismounted.

As a preferred embodiment of the present invention, when the capping beam is an oblate pier, S7 specifically includes the following steps:

s7.1: vertically cutting the longitudinal center line of the bent cap, and dividing the bent cap into two cutting blocks with independent pier studs;

s7.2: after the steel wire rope is tightly hung by a crane, the steel wire rope is transversely cut on the pier stud, the steel wire rope is hoisted and crushed after being separated, and the steel wire rope of the crane is bound at the connecting part of the pier stud and the cover beam. The bent cap and one part of the pier stud are detached and lifted together, so that the bent cap is conveniently and stably lifted, and the cover of the oblate pier stud is rapidly and safely detached.

In the preferred scheme of the invention, in the step S3, the rope saw is adopted to cut the anti-collision wall in sections from the starting point direction of the beam end to the end point direction of the beam end, when the anti-collision wall is cut, the anti-collision wall is cut in a direction perpendicular to the bridge floor, after the automobile sling is tightly cut into sections, the anti-collision wall is cut along the intersection surface of the anti-collision wall and the bridge floor, and after one piece of anti-collision wall is cut and hoisted, the next piece of anti-collision wall is cut.

In the preferred embodiment of the present invention, in S4, if the beam is a continuous beam, it is necessary to cut a cutting line along the center line of the cast-in-situ continuous segment at the top of the pier. So that individual beam segments are formed.

In S4, preferably, 2 parallel slits are cut along the cutting line by a wire saw and then the middle portion is chiseled off to form a cut slit having a width of not less than 5cm between adjacent beam segments. Each beam section can be stably tightened through a truck crane under the condition that the beam section is not displaced, and stable hoisting of each beam section is realized.

In S5, a limiting means for limiting the displacement of the cable is provided at each contact point between the cable and the beam wing plate. The beam section is prevented from falling to cause accidents due to the fact that a steel wire rope slides in the lifting and moving process of the beam section, and safety of the beam section in the lifting and moving process is guaranteed.

Preferably, the old bridge sections are dismantled in a retreating mode in which the steps S3, S4 and S5 are carried out at the same span, and the old bridge sections are divided and hoisted piece by piece from the side close to the traffic passing area as a starting point. The removed old bridge of the precast beam occupies a small traffic range and takes less time in the traffic in the removing process, so that the normal traffic of the traffic in the removing process of the old bridge can be ensured to the maximum extent, and the safe and quick removal of the old bridge is realized.

As a preferable scheme of the invention, before cutting, the method also comprises the step of building a water supply system, wherein the water supply system is used for cooling and treating dust fall at the cutting position.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. by adopting the construction method, the existing old precast beam bridge can be safely and quickly dismantled under the condition of not interrupting main line traffic;

2. adopting a traffic control measure of half-width passing or split-width passing and matching with an anti-collision isolation measure, so that the traffic is not interrupted and the driving safety is ensured in the old bridge dismantling process;

3. aiming at the structural characteristics of the old bridge of the precast beam, a hoisting hole is pre-drilled, the beam body is cut span by span after scribing, the steps of cutting, hoisting and crushing are carried out piece by piece, and the dismantling is finished span by span, so that the dismantling safety of each beam section can be ensured;

4. the old bridge dismantling process is uniform, the dismantling process is quick, few broken stones are generated, and the influence on the construction period of a normal traffic line and a new bridge can be avoided to the greatest extent;

5. the removed old bridge of the precast beam occupies a small traffic range and takes less time in the traffic in the removing process, so that the normal traffic of the traffic in the removing process of the old bridge can be ensured to the maximum extent, and the safe and quick removal of the old bridge is realized.

Drawings

Fig. 1 is a schematic flow chart of a construction method for dismantling an old precast beam bridge according to the present invention.

FIG. 2 is a schematic diagram of the corresponding cutting at S4 in example 1.

Fig. 3 is a schematic diagram of a removal sequence of one span of a main old medium bridge in embodiment 1.

Fig. 4 is a side view of a main line old bridge dismantling process in embodiment 1.

Fig. 5 is a schematic side view of a process of removing a main line old medium bridge in embodiment 1.

Fig. 6 is a schematic top view of a main line old medium bridge dismantling process in embodiment 1.

FIG. 7 is a schematic view showing the removal sequence of an old bridge of an overpass in example 1.

Fig. 8 is a side view schematically illustrating a process of removing an old bridge of an overpass in example 1.

FIG. 9 is a second schematic side view of the process of removing an old bridge of an overpass in example 1.

Fig. 10 is a schematic side view three of the process of removing an old bridge of an overpass in example 1.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

As shown in fig. 1, the construction method for dismantling the old bridge of the precast beam according to the embodiment includes the following steps:

s1: traffic control: and closing half-width passing or width-splicing section passing.

Specifically, for the old medium main bridge, temporarily sealing a half of the adjacent lanes of the old bridge to be dismantled, passing the other half of the old bridge, or carrying out traffic passing on the width splicing section, dismantling the old bridge, closing the half of the lanes corresponding to the old bridge to be dismantled on the main line, passing the other half of the old bridge, regulating traffic control measures after dismantling the half of the old bridge, regulating the passing lanes, ensuring that no vehicle passes in a certain area of the bottom surface and the side surface of the corresponding dismantled half of the old bridge in the dismantling process of the old bridge, and ensuring that normal traffic in the dismantling process of the old bridge is passed to the maximum extent.

S2: setting anti-collision isolation measures: and arranging anti-collision isolation measures between the construction area and the traffic area, wherein the anti-collision isolation measures comprise a safety spacing distance not less than 1m and at least one span anti-collision isolation fence.

Concretely, to the old middle bridge of thread, set up crashproof isolation measure between construction district and the passway district, avoid old bridge to demolish in the construction, the rubble that the old structure of cutting produced splashes to the passway district, in order to ensure the current security of vehicle, in this embodiment, install the steel pipe stand additional on the anticollision barrier between construction district and passway district, pass through bolt fastening on the anticollision barrier bottom the steel pipe stand, full cloth dense mesh safety net on the steel pipe stand, form the rail, in order to eliminate the danger that the stone splashes when cutting, and simultaneously, reserve the safe spacing distance that is not less than 1m wide outside the anticollision barrier, the biggest stone risk that splashes that the old bridge of avoiding demolishs the process appearance, guarantee the smoothness of old bridge demolishs the process, go on safely.

Specifically, to the condition of the inboard guardrail of left and right width sharing, before demolising the inboard guardrail, protect at the portable steel guardrail of about 1m department installation apart from the guardrail, form the wide safe interval distance that is not less than 1m, ensure that the bridge half width is demolishd the in-process, and remaining half width can normally pass, guarantees the driving safety in passerby district.

S3: dismantling the anti-collision wall: the method comprises the steps of cutting the anti-collision wall in a segmented mode from the beam end starting point direction to the beam end terminal point direction by adopting a rope saw, cutting the anti-collision wall in a direction perpendicular to the bridge floor, dividing the anti-collision wall into sections at intervals of 4m, arranging at least two hoisting holes with the diameter not less than 100mm in each section, cutting the anti-collision wall along the intersection surface of the anti-collision wall and the bridge floor after the automobile sling needs to be cut tightly, cutting and hoisting one section, and then cutting the next section, so that the anti-collision wall is lifted and broken piece by piece.

Specifically, the inside and outside anticollision barrier all adopts diamond saw cutting method segmentation cutting, hoist and mount to demolish, in this embodiment, demolish for the example with the old bridge of a certain precast beam, adopt S3 step to cut the crashproof wall and demolish, two hole for hoist diameters are about 100mm, set up in the middle part position of every segmental height, divide and establish 1/4 and 3/4 department at length, every segmental weight is about 2.96t, adopt the truck-mounted crane to hoist, transport to appointed crushing field through the tipper and carry out the breakage.

Specifically, the detachment of the anti-collision wall and the detachment of the beam plate are carried out at the same span, so that the anti-collision wall on the bridge span which is not detached by the beam plate can continue to play a role in protection.

S4, beam body splitting: according to the old bridge drawing, on wing plates on two sides of a web plate at 1/4 and 3/4 in the length direction of each beam, a drilling machine is used for drilling hoisting holes with the diameter not less than 150mm along wet joints, cutting lines are drawn along the center lines of the wet joints, a rope saw is used for cutting 2 parallel joints along the cutting lines and then chiseling the middle parts, cutting joints with the width not less than 5cm are formed between adjacent beam sections, and independent beam sections are formed.

Specifically, as shown in fig. 2, a cutting line is drawn at the center of a flange plate wet joint (shown by a horizontal dotted line in fig. 2) connected between beams, a drilling mark is made at a hoisting hole of each beam and a hole is drilled (shown by a circular hole in fig. 2), so that the hoisting holes of adjacent beam sections are symmetrical by taking the cutting line as the center, a diamond rope saw is adopted to cut along the cutting line drawn along the center line of the flange plate wet joint, the separation of single beam sections can be realized, for an old bridge of a continuous beam, a cutting line is drawn along the center line of a cast-in-place continuous section on the top of a pier (shown by a vertical dotted line in fig. 2), the separation of the span-by-span single beam sections of the beam plates is realized, and the beam sections are divided into one piece per piece and lifted off one piece, so that the old bridge is detached by cutting and lifting.

S5: hanging and moving the beam section: and (3) placing at least one truck crane supporting leg on the previous bridge span or the ground beside the old bridge, binding a single-piece beam section through a steel wire rope, setting a limiting measure for limiting the displacement of the steel wire rope on each contact point of the steel wire rope and a beam section wing plate, and cutting and lifting the old bridge section piece by piece span until the half width of the full bridge is removed.

Specifically, after the truck crane is in place, a commander commands the boom to stop to a specified position, checks whether the extension or contraction of the boom of the crane is normal, whether the arrangement of the steel wire ropes is neat, whether the foundation is hard, whether the support legs of the crane are stable, whether the foot sleepers are stable, and whether the body of the crane is stable, and can carry out the operation of the crane beam after the above preparation work check is ready.

Specifically, during the hanging beam, site constructor fixes the lifting rope at the roof beam section and sets for the position, can directly pass the hole for hoist with wire rope, and wire rope can not produce the displacement when guaranteeing to hoist, also can be according to actual conditions, and the conventional mechanical stop gear of installation or the chisel removes partial roof beam section concrete in hole for hoist position and form the recess, avoids wire rope to produce relative movement with the roof beam section at the hanging in-process that moves, reduces the roof beam section and falls the risk.

Specifically, when the beam is hung, the crane falls off the hook, after the steel wire rope is tied, the crane slowly lifts the hook, after the beam plate is lifted by 5-10cm, the crane pauses for 3-5 minutes without problems, the beam is continuously lifted, the stress condition of each part is checked in a hovering mode, if no abnormity exists, the beam section is lifted away through actions such as amplitude variation, rotation and the like, the beam section is placed in a bridge bottom storage area, a specially-assigned person conducts commanding in the lifting process, the crane starts to lift the beam from a first beam position needing to be dismounted, the level of the beam plate is kept as much as possible in the lifting process of the beam plate, collision between the lifted beam plate and other beam plates is avoided, and after the beam section is stably placed in the bridge bottom storage area, the lifting preparation work of a next beam section is conducted.

Specifically, when two truck cranes are adopted, the rated hoisting capacity of a single truck crane is ensured to be more than 80% of the weight of a beam when the truck crane is selected.

S6: and adjusting traffic control, repeating S2-S5, and completing the removal of the remaining half-width old bridge plate span by span.

Specifically, S3, S4, and S5 are performed in the same span, each span is a loop, and the removal of each span does not affect the removal of the next span, so that the removal of the old bridge is realized span by span.

Preferably, as shown in fig. 3, in the case of the old main line medium bridge, the demolition sequence is a backward demolition old bridge segment that is split and hoisted piece by piece from span by taking one end of the bridge deck to be demolished as a starting point, in the case of the inter-communicating cross-line bridge, the backward demolition old bridge segment that is split and hoisted piece by piece from span by taking the main line center pier stud as a starting point, that is, in the demolition process of all bridge types, the demolition sequence is: the beam sections are segmented piece by piece and hung away from one side closest to the traffic passing area, and the hanging direction faces away from one side of the traffic passing area, so that the old bridge is removed in the process of construction close to the traffic passing area, the time is shortened, the influence on the traffic passing area is avoided to the greatest extent, and the old bridge is guaranteed to be smoothly and safely removed under the normal traffic condition.

Specifically, as shown in fig. 4-6, in the dismantling process of an old medium bridge of a certain main line, crane legs are arranged on the bridge floor of the previous span of the old bridge, width splicing sections are preset on two sides of the old bridge in the width direction, the crane legs pass through the width splicing sections, and each span is subjected to dismantling, sequential piece-by-piece segmentation, hanging-off and breaking as shown in fig. 3.

Specifically, a crane with legs supported on the ground beside the old bridge can be adopted according to the actual environment of the old bridge on site.

Preferably, as shown in fig. 7-10, in the process of dismantling an old overpass, the old overpass is divided into flange parts at two sides or the sum of the flange and part of the beam sections by a scribing line, the beam sections at the middle part are divided and lifted one by one, and each area is divided and lifted one by one, and the beam sections are divided and lifted one by one from the edge of the flange part at one side according to the lifting sequence shown in fig. 7, and are cut and lifted one by one to be close to the abutment, then the crane is transferred, and the beam sections are divided and lifted one by one along the transverse direction of the bridge from the edge of the flange part at the other side, and after the flange part is dismantled, the beam sections at the middle part are divided and lifted one by one, so that the structural stability of the rest beam sections in the dismantling process is ensured to the maximum extent, so that only part of traffic below the corresponding construction area needs to be sealed and no cutting is needed in the process of dismantling the overpass, and the influence time of the overpass dismantling process on normal traffic is shortened.

S7: dismantling the capping beam: assembling a bent cap dismantling platform on one side of the pier stud close to the ground, lifting the bent cap dismantling platform to a proper height of the top of the pier stud for fixing, and cutting the bent cap in sections on the bent cap dismantling platform, and hanging the bent cap section by section for crushing.

The staple bolt is assembled in pier stud bottom position that the bent cap was demolishd to needs, sets up the steel structure platform on the staple bolt, then promotes to suitable position, pastes the rubber slab at the staple bolt inboard, makes staple bolt and pier stud hug closely, fastens the staple bolt, and shaping staple bolt steel structure platform supplies the workman to operate the concrete block of cutting the bent cap, under the platform, sets up "zigzag" safety cat ladder to supply the workman to go up and down the platform.

Specifically, taking a capping beam of a certain cylindrical pier as an example, S7 specifically includes the following steps: s7.1: the cover beam is scribed and segmented into a cantilever part, a middle part of two pier columns and a pier top; s7.2: on two side faces of the cantilever part along the width of the cover beam, on the basis of the cover beam, drilling a through hole with the diameter of 35mm at a position with the height of 1/3 from two end faces 1/4 of the cantilever part by using a pneumatic drill, inserting a threaded rod with the diameter of 32mm which is not shorter than 50cm into the hole, exposing at least 30cm, when a crane steel wire rope binds the cantilever part, positioning the threaded rod between two adjacent hoisting points, hoisting the cantilever part tightly by using the steel wire rope of 1 130t crane, then cutting and separating the cantilever part by using a rope saw, cutting the cantilever part from the cover beam, and finally hoisting the cantilever part to a flat car and transporting the flat car to a special crushing site for crushing; s7.3: binding type hoisting construction is carried out on the space between two pier studs, the length of the region is 8.1m, the height is 1.5m, the width is 1.3m, the weight is about 28.83T, the region is divided into three sections through longitudinal scribing, after each section is tightly hoisted in a binding type hoisting mode by adopting a crane of 130T, a rope saw is used for cutting and hoisting each section in a longitudinal section by section, each section is 13.7T in weight, the operating radius of the crane is 8m, and each section is hoisted and crushed; s7.4: and (3) cutting the side surface and the top surface of the top of the pier by adopting a rope saw, drilling the top surface of the bent cap after cutting off the bent cap stirrup, burying an expanding agent, and chiseling by adopting manpower after the concrete cracks.

Specifically, taking a capping beam of a certain oblate pier column as an example, S7 specifically includes the following steps: s7.1: vertically cutting the longitudinal center line of the bent cap, and dividing the bent cap into two cutting blocks with independent pier studs, wherein the cutting speed is about 51.8t, 1 260t truck crane is planned to be used for hoisting, and the hoisting weight is 58.8t when the crane support legs fully extend to the working radius of 7m and the arm length is 27.1 m; s7.2: and (3) using lifting ropes of 1 260t crane to tighten two sides of the joint of the capping beam and the pier stud and the capping beam, so that the crane tightly lifts the cutting block, transversely cuts on the pier stud, and lifts, lifts and crushes the cut block after separation.

Specifically, after a coated pier stud dismantling platform is built on a pier stud, the pier stud is transversely cut and divided into pier stud cutting blocks with the height of about 2m, holes are drilled in the middle area of each cutting block in advance, the weight of each cutting block is controlled within 17t, and a 260t truck crane is adopted for hoisting.

Preferably, before the beam body, the bent cap and the pier stud are cut, the method further comprises the step of building a water supply system, wherein the water supply system is used for cooling and treating dust fall at the cutting position, the beam section lifted away is crushed by a hydraulic crushing hammer, and the crushed material is reused as unscreened broken stone and is used for culvert foundation replacement and filling, road bed unscreened broken stone and road bed soft foundation replacement and top broken stone layer filling in the road changing process.

According to the construction method for removing the old bridge of the precast beam, when the bent cap and the pier stud are removed, the steps of construction preparation, determination of a cutting surface, installation of a rope saw, binding and fixing of a steel wire rope, cutting and hanging of a cutting block are sequentially carried out, the processes of block-by-block cutting and hanging of the bent cap and the pier stud are achieved, in the cutting process, the cutting part is blocked by a corresponding construction platform, splashing of broken stones can be effectively avoided, and safe and rapid removal of the bent cap and the pier stud is achieved.

The construction method for dismantling the old bridge of the precast beam comprises the steps of sequentially setting anti-collision isolation measures, dismantling an anti-collision wall, placing a crane, binding a beam section by a truck-mounted steel wire rope, cutting a wet joint to divide a beam body, moving the beam section by a truck-mounted crane, crushing the beam section in situ or lifting off to crush, adjusting traffic control, transferring the truck-mounted crane to the other half range to be in place, repeating the steps until the whole beam body is dismantled, dismantling a cover beam and dismantling a pier stud, and realizing the process of segmenting, lifting off and crushing the old bridge of the precast beam step by step and completing the dismantling step by step.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A construction method for dismantling an old bridge of a precast beam is characterized by comprising the following steps:

2. The construction method for dismantling the old bridge of the precast beam according to claim 1, wherein in the case of the cap beam of the cylindrical pier, the S7 comprises the following steps:

s7.4: and respectively cutting the side surface and the top surface of the top of the pier, drilling the top surface of the bent cap after the bent cap stirrup is cut off, burying an expanding agent, and chiseling by adopting manpower after the concrete cracks.

3. A method as claimed in claim 2, wherein in S7.2, on both sides of the cantilever part along the width of the bent cap, a 35mm diameter through hole is drilled by a pneumatic drill at a height 1/3 from both end faces 1/4 of the cantilever part on the basis of the bent cap, a 32mm diameter threaded rod having a length of not less than 50cm is inserted into the through hole, at least 30cm is exposed, and the threaded rod is located between two adjacent hanging points when the cantilever part is bound by a crane cable.

4. The construction method for dismantling the old bridge of the precast beam according to claim 1, wherein when the capping beam is an oblate pier, the S7 comprises the following steps:

s7.2: after the steel wire rope is tightly hung by a crane, the steel wire rope is transversely cut on the pier stud, the steel wire rope is hoisted and crushed after being separated, and the steel wire rope of the crane is bound at the connecting part of the pier stud and the cover beam.

5. The construction method for dismantling an old bridge of precast girders according to claim 1, wherein in S3, the crash wall is cut by a wire saw from the starting point direction of the girder end to the ending point direction of the girder end, the cutting is performed in a direction perpendicular to the bridge deck, after the automobile sling is tightened to the required cutting section, the cutting is performed along the intersection surface of the crash wall and the bridge deck, and after one cutting is completed, the next cutting is performed.

6. A method of constructing an old bridge of precast girders according to claim 1, wherein in S4, if the girder is a continuous girder, a cutting line is additionally cut along a center line of a cast-in-place continuous section of a pier top.

7. A method of constructing an old bridge of precast girders according to claim 6, wherein in S4, when the girder body is divided, 2 parallel slits are cut along the cutting lines by a wire saw and then the middle portion is chiseled off to form a cutting slit having a width of not less than 5cm between the adjacent girder segments.

8. A construction method for dismantling an old bridge made of precast girders according to claim 1, wherein a stopper for limiting displacement of the wire rope is provided at each contact point of the wire rope with a flange of the girder section at S5.

9. The construction method for dismantling the old bridge of a precast beam as set forth in claim 1, wherein S3, S4 and S5 are performed in the same span, and the old bridge segment is dismantled in a retreat type of being divided and hoisted piece by piece from a side close to the traffic area as a starting point.

10. A construction method for dismantling an old bridge of precast girders according to claim 1, further comprising the step of constructing a water supply system for cooling and dust-reducing treatment of a cutting position before cutting.