CN117328382A - Box girder dismantling process - Google Patents

Abstract

The invention provides a box girder dismantling process, which comprises the following steps: cutting the bridge section by section along the bridge direction to form a plurality of sections of dismantling sections; cutting the demolition sections in the safety demolition area section by section along a direction perpendicular to the bridge direction so as to divide the demolition sections into a plurality of beam sheets; dividing a plurality of beam sheets in the same dismantling section into at least two beam sheet groups, wherein brackets are respectively arranged at two ends of each beam sheet group, and the brackets fix a plurality of beam sheets in the same beam sheet group into a whole; connecting a lifting appliance to the bracket so as to sequentially move the two beam sheet groups to a collecting area; and blasting demolition is carried out on the demolition sections outside the safety demolition area. According to the box girder dismantling process provided by the invention, the dismantling section is divided into the plurality of girder segments, the plurality of girder segments are divided into the two girder segment groups through the two groups of brackets, the brackets are connected with the lifting appliance, and the lifting appliance lifts the girder segment groups twice, so that the plurality of girder segments are transported twice, and the dismantling efficiency of the bridge is greatly improved.

Description

Box girder dismantling process

Technical Field

The invention belongs to the technical field of bridge construction, and particularly relates to a box girder dismantling process.

Background

With the rapid increase of urban traffic and traffic axle load, the requirements on the traffic capacity and service level of the bridge are continuously improved, most early concrete box bridges are difficult to meet the current driving requirements under large traffic and high load, and with the occurrence of the defects of the self-deck plate structure of the concrete bridge and engineering diseases, the structural safety and normal traffic of the existing concrete box bridges are more affected, so that the need of dismantling the box bridges is comprehensively considered.

At present, bridge demolition is mainly a mechanical crushing method, air pick is used for drilling holes in a supporting beam, and after blasting is set, concrete blocks are manually and mechanically chiseled and cleaned. However, when the bridge erected above the railway 7 section is dismantled, in order to avoid affecting the safety of train operation, the handling of the hanging down and stopping procedures is needed in advance when the mechanical crushing method is used for construction, the concrete blocks are manually or mechanically chiseled, the cleaning efficiency is low, the whole construction period is long, the railway cannot normally run, and the potential safety hazard of bridge construction on the running of the railway 7 below is improved by long-term construction.

Disclosure of Invention

The embodiment of the invention provides a box girder dismantling process, which aims to solve the technical problems that the existing bridge dismantling method wastes time and labor when a bridge above a railway is dismantled, and the normal running of the railway is affected.

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

the box girder dismantling process comprises the following steps:

cutting the bridge section by section along the bridge direction to form a plurality of dismantling sections, wherein the cutting lines between adjacent dismantling sections correspond to bridge piers;

cutting the demolition sections in the safety demolition area section by section along a direction perpendicular to the bridge direction so as to divide the demolition sections into a plurality of beam sheets;

dividing a plurality of beam sheets in the same dismantling section into at least two beam sheet groups, wherein each beam sheet group comprises at least two beam sheets, two ends of each beam sheet group are respectively provided with a bracket, and the brackets fix the plurality of beam sheets in the same beam sheet group into a whole;

connecting a lifting appliance to the bracket so as to sequentially move the two beam sheet groups to a collecting area, and crushing the beam sheet groups in the collecting area;

and blasting demolition is carried out on the demolition sections outside the safety demolition area.

In one possible implementation manner, the bridge is cut segment by segment along the bridge direction to form a plurality of demolishd segments, and the cutting line between adjacent demolishd segments is located before the corresponding bridge pier, and the method further includes:

and removing auxiliary facilities on the surface of the bridge.

In one possible implementation, the accessory facility is gradually removed from both ends of the bridge to the center along the bridge direction.

In one possible implementation, before the section of the demolition section located above the railway is cut section by section in a direction perpendicular to the bridge direction, the method further comprises:

and removing the pavement on the surface of the bridge.

In one possible implementation manner, after the pavement of the bridge surface is removed, the method further includes:

dismantling the guardrail on the upper surface of the bridge, and specifically comprising the following steps:

measuring the thickness of the guardrail;

drilling holes on the guardrails, vertically cutting slits, and drilling holes to 5cm of concrete outside the guardrails;

pre-hanging the guardrail, and horizontally cutting the bottom of the guardrail to form a water interception ridge;

dividing the guardrail into a plurality of guardrail sections;

and sequentially moving the guardrail sections.

In one possible implementation, before the beam sheets are divided into two beam sheet groups by the two groups of brackets, the method further comprises:

and jacking up the beam piece.

In one possible implementation manner, after the beam sheet is jacked up, the method further includes:

and temporary steel upright posts and temporary scaffolds are built at the bottoms of the two ends of the dismantling section.

In one possible implementation, the bridge is divided into 5 spans along the bridge direction;

the dismantling section is transversely divided into 8 pieces along the bridge, and each beam piece group comprises 4 beam pieces.

In one possible implementation, the bracket includes:

the lower supporting plate is provided with a plurality of lifting holes along the thickness direction; and

the upper clamping plate is provided with a plurality of through holes corresponding to the lifting holes, a fixing space for fixing the beam piece is formed between the upper clamping plate and the lower supporting plate in a surrounding mode, and the fixing is achieved between the upper clamping plate and the lower supporting plate through fasteners penetrating through the lifting holes and the through holes.

In one possible implementation, the hanger drives the support to test the crane before the support sequentially moves the two beam sheet sets to the collection area through the hanger.

Compared with the prior art, the box girder dismantling process provided by the invention has the advantages that the dismantling section is divided into a plurality of girder sheets, the girder sheets are divided into two girder sheet groups through the two groups of brackets, the brackets are connected with the lifting appliance, and the lifting appliance lifts the girder sheet groups twice to realize the transportation of the girder sheets twice; the beam sheets can be completely removed only by two times, so that the bridge removal efficiency is greatly improved; the beam piece cannot fall onto the railway, so that the normal operation of the railway is prevented from being influenced, the risk of bridge disassembly on railway driving is reduced, and the driving safety of vehicles under the bridge is improved.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.

Fig. 1 is a schematic structural view of a dismantling section of a box girder dismantling process according to a first embodiment of the present invention;

FIG. 2 is a schematic view illustrating the removal of a guardrail according to an embodiment of the present invention;

FIG. 3 is a schematic view of an assembly of a spreader and beam employed in accordance with an embodiment of the present invention;

FIG. 4 is a schematic view of an assembly of brackets and beam segments employed in accordance with an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a limiting component according to a second embodiment of the present invention.

Reference numerals illustrate:

1. a bracket; 11. a lower support plate; 12. an upper clamping plate; 13. a fastener;

2. a beam sheet group; 21. a beam piece;

3. a lifting appliance;

4. guard bars; 41. a water cutting bank; 42. a guardrail section;

5. a limit component; 51. a baffle; 52. a buffer member;

6. temporary scaffolding;

7. railway.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

It should be noted that the terms "length," "width," "height," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," "tail," and the like indicate an orientation or positional relationship based on that shown in the drawings, merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the invention.

It should also be noted that unless explicitly stated or limited otherwise, terms such as "mounted," "connected," "secured," "disposed," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. Furthermore, the meaning of "a plurality of", "a number" is two or more, unless explicitly defined otherwise.

Referring to fig. 1 to 5, a case beam dismantling process according to the present invention will now be described. The box girder dismantling process comprises the following steps: cutting the bridge section by section along the bridge direction to form a plurality of dismantling sections, wherein the cutting lines between the adjacent dismantling sections correspond to the bridge piers; cutting the demolition sections in the safety demolition area section by section in a direction perpendicular to the bridging direction to divide the demolition sections into a plurality of beam sections 21; dividing a plurality of beam sheets 12 in the same dismantling section into at least two beam sheet groups 2, wherein each beam sheet group 2 comprises at least two beam sheets 21, two ends of each beam sheet group 2 are respectively provided with a bracket 1, and the brackets 1 fix the plurality of beam sheets 21 in the same beam sheet group 2 into a whole; connecting a lifting appliance 3 to the bracket 1 so as to sequentially move two beam sheet groups 2 to a collecting area, and crushing the beam sheet groups 2 in the collecting area; blasting demolition is carried out on demolition sections outside the safety demolition area.

It should be noted that, the collecting area is far away from the railway 7, and the beam sheet group 2 is moved into the collecting area for crushing, so that the cleaning is convenient, and the influence on the formation of the railway 7 is avoided.

It should be noted that, referring to fig. 3, the safe demolition area is an area capable of affecting the railway 7, taking the demolition section as 5 sections, the railway 7 is located below a third span, the third span is located above the railway 7, the railway 7 is blocked by conventional blasting demolition, normal operation of the railway 7 is affected, the second span and the fourth span are respectively adjacent to the third span, the situation that concrete blocks drop onto the railway 7 is likely to occur during blasting demolition, and the second span, the third span and the fourth span are close to the railway 7, and cause potential threat to driving of the railway 7, so that the second span, the third span and the fourth span belong to the safe demolition area; the first span and the fifth span are far away from the railway 7, so that the blasting construction does not influence the safe driving of the railway 7, and therefore, the first span and the fifth span belong to the outside of a safe dismantling area.

The two beam sheet groups 2 are arranged in sequence in a direction perpendicular to the bridge direction.

It should be noted that, referring to fig. 3, the vertical dotted line represents the cutting line between the adjacent demolition sections. The bridge is divided into five spans by four cutting lines, and the third span dismantling section is positioned right above the railway 7.

It should be noted that the principle adopted in this embodiment is that the continuous beam is changed into a simply supported beam, and in the process of adjusting the simply supported beam off the site, preferably, the dismantling section is sequentially divided into 8 beam pieces 21 along the direction perpendicular to the bridge direction, and the beam piece group 2 is divided into two.

After the beam sheet group 2 is lifted off the site, the residual capping beam, pier stud and abutment on the site are removed and cleaned.

Compared with the prior art, the box girder dismantling process provided by the embodiment divides the dismantling section into a plurality of girder segments 212, divides the girder segments 21 into two girder segment groups 2 through two groups of brackets 1, connects the brackets 1 with the lifting appliance 3, and the lifting appliance 3 lifts the girder segment groups 2 twice to realize the transportation of the girder segments 21 twice; the plurality of beam sheets 21 can be completely dismantled only by two times, so that the bridge dismantling efficiency is greatly improved; the beam piece 21 cannot fall onto the railway 7, so that the normal operation of the railway 7 is prevented from being influenced, the risk of bridge disassembly on running of the railway 7 is reduced, and the running safety of vehicles under the bridge is improved.

During implementation, the bridge is cut section by section along the bridge direction to form a plurality of dismantling sections, and the cutting lines between the adjacent dismantling sections are positioned before the corresponding bridge piers, and the bridge surface dismantling device further comprises auxiliary facilities for dismantling the bridge surface. The bridge deck auxiliary structure mainly comprises a longitudinal anti-throwing net and a driving anti-dazzling plate of the railways 7 on two sides. The full bridge is symmetrically dismantled, and the steel guardrails 4 and the anti-throwing net at each side are dismantled from two ends to the middle, and the steel guardrails are dismantled piece by piece.

The bridge deck auxiliary structures also comprise steel guardrails, bridge cover plates, pipe box brackets, communication cables and the like. The first span of the right width is directly and manually dismantled by the anti-throwing net, the steel guard rail, the pipe box, the cable and the bridge cover plate, and the dismantling of the structure is carried out in sections. When the anti-throwing net is removed, the anti-throwing net is tensioned towards the direction of the bridge deck by using a steel wire rope in advance, nuts at the bottom of the anti-throwing net are manually removed, the anti-throwing net is placed on the bridge deck, and the anti-throwing net is prevented from falling onto the railway 7. The pipeline and the cable are firmly bound by the rope before being segmented, and the structure is manually lifted to the bridge deck after being segmented and cut. The pipe box bracket between the two plates is cut off by an angle grinder. And after all the structural objects are removed, all the structural objects are transported out of the construction site.

In some embodiments, the accessory facilities are gradually removed from both ends of the bridge to the center along the bridge direction. The auxiliary structures can be gradually detached from the two ends, and after the auxiliary facilities at the two ends are detached, the road at the top of the bridge is widened, so that the auxiliary facilities at the middle part of the bridge deck are convenient to carry.

In some embodiments, the demolition section located above the railway 7 also includes demolishing the pavement of the bridge surface prior to the section-wise cutting in a direction perpendicular to the bridge direction. The pavement on the surface of the bridge needs to be removed to facilitate the cutting of the subsequent bridge, and the weight of the beam piece 21 is reduced.

In the concrete implementation, the pavement is dismantled along the bridge direction in one direction, a milling machine is used for milling, the waste residue after milling is put into an automobile, and the waste is transported to a designated place for stacking.

In some embodiments, in conjunction with fig. 2, after the removing of the pavement of the bridge surface, the method further includes: dismantling the guardrail 4 on the upper surface of the bridge, and specifically comprising the following steps: measuring the thickness of the guardrail 4; drilling holes on the guardrail 4, vertically cutting slits, and drilling holes to 5cm of concrete outside the guardrail 4; pre-hanging the guardrail 4, and horizontally cutting the bottom of the guardrail 4 to form a water interception ridge 41; dividing the guardrail 4 into a plurality of guardrail sections 42; the plurality of guardrail sections 42 are transported in sequence. The guardrails 4 are arranged on two sides of the bridge, so that the cutting of the bridge is hindered, and the cutting angle and the cutting position are affected.

As a specific embodiment of the removal of the guardrail 4, the specific removal steps of the guardrail 4 are as follows:

the concrete guardrail 4 is pretreated to reduce the work load. Before pretreatment, the horizontal and vertical thickness of the concrete guardrail 4 is measured, and a pretreatment safety position line is determined. After the measurement and paying-off, a drilling machine is used for drilling a lifting hole, cutting a slit vertically along the guardrail 4, the aperture is 100mm, and when the drilling is carried out until the concrete outside the guardrail 4 reaches 5cm, the drilling is stopped. Along the horizontal drilling of guardrail 4 horizontal cut line position, aperture 100mm, when drilling to guardrail 4 outside concrete 5cm, stop drilling, as the water stop bank, prevent that guardrail 4 from hanging from the back, leak down the bridge, guardrail 4 horizontal cut line position also can use hydraulic disc saw cutting, when cutting to guardrail 4 outside concrete 5cm, stop cutting, prevent to wear the hole or cut the seam runs through, lead to muddy water on the bridge floor to spill railway 7, influence railway 7 driving safety. When the horizontal direction of the guardrail 4 adopts drilling or hydraulic disc saw cutting operation, 20cm is reserved every one meter without drilling or cutting pretreatment, so that the concrete guardrail 4 is prevented from overturning, and the driving safety of the railway 7 is prevented from being influenced. And cutting the concrete of the rest part of the vertical drilling hole of the concrete guardrail 4 by using a disc saw in the sealing point, dividing the guardrail 4 into independent small sections, and drilling the rest part of the hoisting hole by using a drilling machine. And (3) horizontally cutting residual concrete after drilling along the bottom of the guardrail 4 from the middle to the two ends by using a disc saw, and immediately transporting the concrete guardrail 4 to a designated position by using an automobile for treatment after the segmented cutting of the concrete guardrail 4 is completed until all the guardrails 4 are lifted off.

It should be noted that the bridge is sequentially divided into 5 spans, and the guardrails 4 of the third span are not removed, and the guardrails 4 of the other spans are removed.

In some embodiments, the plurality of beam sheets 21 further comprises, before being divided into two beam sheet groups 2 by the two groups of brackets 1: the beam 21 is lifted up. The beam piece 21 is jacked up to facilitate the installation of the bracket 1 and the lifting of the beam piece 21.

As a concrete embodiment of jacking up the beam plates 21, the beam plates 21 are periodically subjected to a jack system, the bottom of each beam plate 21 is provided with a jack, and a plurality of jacks jack up synchronously so as to ensure that a plurality of beam plates 21 are positioned at the same horizontal height.

In specific implementation, synchronous jacking jacks are distributed on the bridge bent cap, and the whole bridge is jacked by using a synchronous jacking system, wherein the jacking height is not more than 1cm.

In some embodiments, after the beam piece 21 is jacked up, temporary steel columns and temporary scaffolds 6 are built at the bottoms of the two ends of the demolition section. The temporary steel upright post and the temporary scaffold 6 are used for supporting the demolishing section, so that the demolishing section is separated from the pier, and the construction is convenient.

In some embodiments, referring to fig. 1 and 3, the bridge is divided into 5 spans in the bridge direction; the demolition section is divided into 8 pieces along the bridge transverse direction, and each beam sheet group 2 comprises 4 beam sheets 21.

In the concrete implementation, the depth of the hinge joint of the beam piece 21 is 14cm, a disc saw is used for cutting 2 paths along 5cm on two sides of the center line of the hinge joint, and the cutting width is 10cm. The joint is cut down from the top surface of the bridge deck pavement to a depth of 20cm, the hinge joint is not cut through, water in the joint is dried by an air compressor, then concrete in the joint is removed by a small breaking hammer matched with an electric pick, and the adjacent beam pieces 21 are completely separated.

The bridge of the fifth span is removed from the middle, the bridge of the third span is removed first, the second span and the fourth span are removed, and finally the first span and the fifth span are demolished by blasting.

The 8 beam sheets 21 are completely dismantled twice, and only need to be dismantled twice, so that the times of vertical stopping are greatly reduced, the construction period is shortened, and the potential safety hazard is reduced. And only one hinge joint needs to be cut by a single dismantling section, so that the construction cost is reduced.

In some embodiments, referring to fig. 4, the bracket 1 includes a lower plate 11 and an upper plate 12. The lower supporting plate 11 is provided with a plurality of lifting holes along the thickness direction; the upper clamping plate 12 is provided with a plurality of through holes corresponding to the lifting holes, a fixing space for fixing the beam piece 21 is formed by enclosing between the upper clamping plate 12 and the lower supporting plate 11, and the upper clamping plate 12 and the lower supporting plate 11 are fixed by fasteners sequentially penetrating through the lifting holes and the through holes.

The support 1 that this embodiment provided simple structure has set up punch holder 12 and bottom plate 11, forms fixed space between punch holder 12 and the bottom plate 11, and fixed space exists the installation position of a plurality of roof beam pieces 21, and fixed space can once only fix a plurality of roof beam pieces 21 for when roof beam piece was dismantled, the number of times that hangs down stopped was reduced, very big shortened whole time limit for a project and spent time, the efficiency that the roof beam piece was dismantled was improved, the time of traffic recovery is advanced, has reduced the traffic risk, and then has improved traffic safety.

As a specific embodiment of the bracket 1, the width of the lower blade 11 is not smaller than the width of the upper blade 12, and the length of the upper blade 12 is not greater than the length of the lower blade 11.

The length of the upper clamping plate 12 is three-fourths of the overall width of the four beam pieces 21, the length of the lower supporting plate 11 is the overall width of the four beam pieces 21, and a fixed space is formed between the upper clamping plate 12 and the lower supporting plate 11.

After the upper plate 12 and the lower plate 11 are mounted, the front side edges, the rear side edges, and the left and right side edges of the upper plate 12 and the lower plate 11 are parallel to each other.

In some embodiments, referring to fig. 5, a limiting assembly 5 is disposed in the fixed space, and the limiting assembly 5 includes a plurality of vertically disposed baffles 51 and a plurality of buffers 52. The baffle plates 51 are arranged at intervals along the length direction of the lower supporting plate 2, clamping grooves 511 are formed in the bottoms of the baffle plates 51, the clamping grooves 511 are matched with the lower supporting plate 2 in a clamping manner, and fixed positions are formed between the adjacent baffle plates 51; the plurality of buffers 52 are fixed to both side plate surfaces of the baffle plate 51, respectively. The clamping groove 511 is matched with the adapting groove of the lower supporting plate 2 in a clamping way, so that the clamping groove 511 can stably move along the length direction of the lower supporting plate 2. The baffle plates 51 fill gaps between the adjacent beam bodies 7, the buffer parts 52 are arranged on the two side plate surfaces of each baffle plate 51, the buffer parts 52 buffer the impact force received by the baffle plates 51, and the baffle plates 51 are matched to jointly fill gaps in a fixed space, so that the stabilizing effect of the clamped beam piece 21 is ensured.

In some embodiments, the hanger 3 drives the bracket 1 to perform test hanging before the bracket 1 sequentially moves the two beam sheet groups 2 to the collecting area through the hanger 3. The test crane ensures the bearing capacity of the lifting appliance 3, and avoids that the force applied by the lifting appliance 3 cannot lift the bracket 1.

The lifting appliance is a bridge girder erection machine, a winch is arranged on the bridge girder erection machine, a rope fixing position is arranged on the upper surface of the upper clamping plate 12, the rope end part of the winch is fixedly connected with the rope fixing position, and the bracket 1 and the corresponding girder piece 21 are lifted through the recovery rope of the winch.

The following are specific examples:

the railway 7 is arranged below the bridge, the bridge is dismantled, the bridge is numbered sequentially along the bridge direction and is divided into 5 spans, the third span is positioned above the railway 7, the whole bridge is a continuous beam, the beam piece 21 is separated by using a disc saw to longitudinally cut hinge joints before the bridge is dismantled, and then the bridge is changed into a simply supported beam from the continuous beam by using a rope saw to transversely cut wet joints.

Comprises the following steps of;

1) A construction site is defined;

before the test hoisting, the roadbeds on the south and north sides of the railway 7 bridge are provided with surrounding baffles with the height of 1.8m to serve as hard protection, non-constructors are forbidden to enter a construction site, and meanwhile business line safety training is carried out on all constructors.

2) Dismantling a bridge auxiliary structure;

the bridge deck auxiliary structure mainly comprises a longitudinal anti-throwing net, a steel guardrail, a bridge cover plate, a pipe box bracket, a communication cable and the like of the railways 7 on two sides. When the anti-throwing net is removed, the anti-throwing net is tensioned towards the direction of the bridge deck by using a steel wire rope in advance, nuts at the bottom of the anti-throwing net are manually removed, the anti-throwing net is placed on the bridge deck, and the anti-throwing net is prevented from falling onto the railway 7. The pipeline and the cable are firmly bound by the rope before being segmented, and the structure is manually lifted to the bridge deck after being segmented and cut. The pipe box bracket between the two plates is cut off by an angle grinder. And after all the structural objects are removed, all the structural objects are transported out of the construction site.

3) Temporary steel upright posts and scaffolds are erected;

the left and right pier capping beams are reinforced by steel upright posts for placing the bridge girder erection machine to reversely drag. Temporary steel columns are arranged on the north sides of the left and right piers, and the supporting legs in the bridge girder erection machine can transmit force to the piers and the temporary steel columns through the girder segments 21, so that the stability of the bridge girder erection machine is enhanced.

And reinforcing the pier capping beam. 2 diameters are arranged side by side at a distance of 0.5m from the cantilever ends at two sidesSteel pipe columns with wall thickness of 12mm, the center distance between the two steel pipe columns is 0.7m, and 2 diameters are arranged between every two piers>Steel pipe column with wall thickness of 12mm, column foundation adopting C30 concrete rectangular foundation with length of 2m, width of 2m and thickness of 1m, and arranged at foundation bottomReinforcing steel mesh. Cutting the top of the cantilever end steel upright post into an oblique angle of 22 degrees, welding a steel plate with the size of 1.0 mm and the thickness of 1.5m on the top, and opening the four corners of the steel plate>And the round hole is then connected with the capping beam entity by an expansion screw.

And a cushion layer is arranged at the bottom of the temporary steel upright column foundation at the north side of the left and right piers, and is 14m long, 3.5m wide and 20cm thick and is poured by C25 concrete. The temporary steel upright post adopts a strip-shaped foundation, the foundation is close to the existing pier column, a steel bar net sheet is arranged at the bottom of the foundation, the length of the foundation is 13m, the width of the foundation is 2.0m, and the height of the foundation is 1.0m, and a steel upright post embedded part is arranged on the foundation; the steel upright post adopts 7 steel pipes in a single row, the transverse center distance of the steel pipes in the encryption area is 1.44m, the transverse center distance of the steel pipes in other areas is 3.0m, the center distance of the steel pipes is 1.0m, the diameter of the steel pipes is equal to that of the existing pier postThe wall thickness is 12mm, two transverse supports are arranged on adjacent steel pipes, a scissor support is arranged between the transverse supports, the supports and the scissor support are welded by using [10 channel steel ], and three H-shaped steel is placed at the top of the upright post to serve as a supporting cross beam.

Temporary steel upright posts are erected on the outer sides of the left and right pier bent caps, the bridge girder erection machine needs to transversely move to the outer sides of the bent caps when the first span and the second span are dismantled, and the steel upright posts are erected for supporting transverse moving tracks outside the bent caps.

The steel upright post adopts a rectangular foundation, the foundation is 3m long, 3m wide and 1m thick, C30 concrete pouring is adopted, the foundation bottom is provided with a reinforcing steel mesh, and the foundation top is provided with 4 diametersThe wall thickness of the steel tube is 12mm, the clear distance between adjacent steel tubes is 1m, a transverse support is arranged in the middle, a scissor support is arranged between the transverse supports, the transverse support and the scissor support are welded by using [10 channel steel ], double-spliced 45I-steel is placed at the top of a steel column to serve as a supporting cross beam, and a 2cm steel plate is welded on the cross beam to serve as a transverse rail pressing platform.

Before pouring the temporary steel upright post foundation, detecting the bearing capacity of the foundation and providing a bearing capacity report, and if the bearing capacity report does not meet the requirement of a consultation unit and is not less than 200kPa, performing sand-included stone replacement or concrete pouring treatment on the foundation under the cushion layer. The periphery of the temporary steel upright post foundation is provided with a water drainage transverse slope and a water interception ditch, so that rainwater is prevented from gathering and soaking the foundation in rainy seasons;

4) Cutting a hinge joint;

the beam piece 21 is divided into 8 pieces, cutting is carried out at the hinge joint position of the fourth beam piece 21 and the fifth beam piece 21, and the cutting adopts disc saw construction operation. The joint is cut down from the top surface of the bridge deck pavement to a depth of 20cm, the hinge joint is not cut through, water in the joint is dried by an air compressor, then concrete in the joint is removed by a small breaking hammer matched with an electric pick, and the adjacent beam pieces 21 are completely separated.

5) Cutting the guard rail 4;

firstly, the guardrail 4 is vertically cut into 5 meters/section, each section of concrete block is drilled with 2 hoisting holes, the aperture is 100mm, the hoisting holes are longitudinally positioned in the center of the guardrail 4 and are transversely positioned at the 1m position of the end part of the guardrail 4, steel wire ropes are penetrated into the holes, and the steel wire ropes are pre-hoisted in advance by a crane to be tightened. Then a rope saw is used for horizontally cutting along the bottom of the guardrail 4 at a position 10cm away from the bridge deck, 10cm is reserved as a water interception ridge, water leakage from the guardrail 4 to the lower part of the bridge is prevented, after the horizontal cutting of the guardrail 4 is completed, a crane is used for hoisting a concrete block away from the bridge deck, and the concrete block is transported to a designated position for treatment;

6) Drilling of beam piece 21 and hoisting of bracket 1

And hoisting a group of beam sheet groups, and performing test hoisting. 1 diameter is drilled at a position 2.0m from the beam end of the central line of each beam piece 21The lifting hole is provided with a lifting hole,the distance between adjacent lifting holes is 1.55m, and the diameter is +.>The finish-rolled threads are used as fasteners 13, and a 1cm steel plate is welded on the top of double-spliced I-steel to form a lower supporting plate 11. After passing through the holes, the bridge girder erection machine places the upper clamping plate 12 at the position of the lifting hole on the top surface of the girder, uses machinery to transport the lower supporting plate 11 to the bottom of the girder, and uses a bridge girder erection machine winch to lift the lower supporting plate 11 to the bottom of the girder in a lifting manner and close to the bottom of the girder. The hoist steel wire rope penetrates from the two middle hoisting holes and is connected with the lower supporting plate 11 and the upper clamping plate 12, the lower supporting plate 11 is hoisted to the beam bottom by using the hoist, the suspender penetrates into the lower supporting plate 11, the beam piece 21 and the upper clamping plate 12 from the hoisting holes on two sides and is temporarily fixed by double nuts, the steel wire rope is withdrawn, the two middle hoisting holes penetrate into the suspender and are fixed by double nuts, the nuts are screwed down for fixation after the 4 suspenders are all installed, and the lower supporting plate 11, the beam piece 21 and the upper clamping plate 12 are tightly adhered to form a whole, so that the whole stability in the hoisting process is ensured;

7) Wet joint cutting and expansion joint removing

Before the wet joint is cut, gaps between the cover beam and the beam piece 21 are filled by using a steel plate (temporary support), so that the overall stability of the beam piece 21 after the wet joint is cut is ensured.

Cutting at the position of the pier top wet joint, taking two rows of holes along the center line of the wet joint by using a water drill with the diameter phi of 100mm, enabling each row of holes to be 15cm away from the center line, penetrating into transversely adjacent holes by using a rope saw to form a closed-loop cutting beam end wet joint, cutting slits with the width of 30cm, cutting the wet joint at the corresponding position of 4 beam pieces 21 by 6.4m, and removing concrete in the slits by using a small breaking hammer and an electric pick after the cutting slits are completed, so that the 4 beam pieces 21 are simply supported by continuous.

The beam piece 21 is put back to the original position after the test hoisting is completed, so that the overall stability of the beam piece 21 after being put back is ensured;

8) Bridge girder erection machine assembly and via hole

The beam piece 21 is dismounted and lifted in a test mode, the SHJQJ410t type is selected, the dead weight of the single beam is 40.5t, the bridge deck pavement weight is 9.7t, the asphalt weight is 4.6t, the guardrail weight is 4.8 t, the total weight of the 4 beam pieces 21 is 241t, the lifting safety coefficient is 1.7 and is larger than 1.5 times of the safety coefficient, and the construction requirement is met. The net width of the bridge girder erection machine is 7.6m, and the width of the 4 girder segments 21 is 6.2m, so that the requirement of hoisting and dismantling the net width is met.

The bridge girder erection machine is transported to the railway north roadbed, a 25t crane is used for unloading and assembling, and the bridge girder erection machine occupies 60m of the railway north roadbed after the assembling is completed;

after the bridge girder erection machine is assembled, power-on debugging is carried out, and the bridge girder erection machine is driven to a first span for preparation and test hanging after the debugging is finished; the front supporting leg of the bridge girder erection machine is pressed on the front transverse moving track, the middle supporting leg is pressed on the middle transverse moving track, the rear transverse moving track is installed after the bridge girder erection machine is in place, and the rear supporting leg is pressed on the rear transverse moving track, so that the via hole of the bridge girder erection machine is completed;

9) Bridge girder erection machine beam disassembly test crane

After the construction preparation is completed, the trial hoisting time is arranged completely according to the key point construction, and the beam piece 21 is removed.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.

Claims (10)

1. The box girder dismantling process is characterized by comprising the following steps of:

cutting the bridge section by section along the bridge direction to form a plurality of dismantling sections, wherein the cutting lines between adjacent dismantling sections correspond to bridge piers;

cutting the demolition sections in the safety demolition area section by section along a direction perpendicular to the bridge direction so as to divide the demolition sections into a plurality of beam sheets;

dividing a plurality of beam sheets in the same dismantling section into at least two beam sheet groups, wherein each beam sheet group comprises at least two beam sheets, two ends of each beam sheet group are respectively provided with a bracket, and the brackets fix the plurality of beam sheets in the same beam sheet group into a whole;

connecting a lifting appliance to the bracket so as to sequentially move the two beam sheet groups to a collecting area, and crushing the beam sheet groups in the collecting area;

and blasting demolition is carried out on the demolition sections outside the safety demolition area.

2. The box girder demolition process of claim 1, wherein the bridge is cut segment by segment along the bridge direction to form a plurality of demolition segments, and cutting lines between adjacent demolition segments are positioned before corresponding piers, further comprising:

and removing auxiliary facilities on the surface of the bridge.

3. The box girder removal process of claim 2, wherein the auxiliary facilities are gradually removed from both ends of the bridge toward the center in the bridge direction.

4. The box girder removal process of claim 1, wherein prior to the segment-wise cutting of the removal segments located above the railway in a direction perpendicular to the bridge direction, further comprises:

and removing the pavement on the surface of the bridge.

5. The box girder removing process of claim 4, further comprising, after removing the pavement of the bridge surface:

dismantling the guardrail on the upper surface of the bridge, and specifically comprising the following steps:

measuring the thickness of the guardrail;

drilling holes on the guardrails, vertically cutting slits, and drilling holes to 5cm of concrete outside the guardrails;

pre-hanging the guardrail, and horizontally cutting the bottom of the guardrail to form a water interception ridge;

dividing the guardrail into a plurality of guardrail sections;

and sequentially moving the guardrail sections.

6. The box girder removal process of claim 5, wherein the plurality of girder segments are further comprised before being divided into two girder segment groups by two groups of brackets:

and jacking up the beam piece.

7. The box girder removal process of claim 6, wherein after jacking up the girder segments, further comprising:

and temporary steel upright posts and temporary scaffolds are built at the bottoms of the two ends of the dismantling section.

8. The box girder demolition process of claim 1, wherein the bridge is divided into 5 spans along a bridge direction;

the dismantling section is transversely divided into 8 pieces along the bridge, and each beam piece group comprises 4 beam pieces.

9. The box girder removal process of claim 1, wherein the bracket comprises:

the lower supporting plate is provided with a plurality of lifting holes along the thickness direction; and

the upper clamping plate is provided with a plurality of through holes corresponding to the lifting holes, a fixing space for fixing the beam piece is formed between the upper clamping plate and the lower supporting plate in a surrounding mode, and the fixing is achieved between the upper clamping plate and the lower supporting plate through fasteners penetrating through the lifting holes and the through holes.

10. The box girder dismantling process as claimed in claim 1, wherein the hanger drives the support to test-hang before the support sequentially moves two girder segment groups to the collection area through the hanger.