CN113235467A - Construction method for dismantling large-span prestressed cast-in-place box girder - Google Patents
Construction method for dismantling large-span prestressed cast-in-place box girder Download PDFInfo
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- CN113235467A CN113235467A CN202110524440.7A CN202110524440A CN113235467A CN 113235467 A CN113235467 A CN 113235467A CN 202110524440 A CN202110524440 A CN 202110524440A CN 113235467 A CN113235467 A CN 113235467A
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D22/00—Methods or apparatus for repairing or strengthening existing bridges ; Methods or apparatus for dismantling bridges
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D2/00—Bridges characterised by the cross-section of their bearing spanning structure
- E01D2/04—Bridges characterised by the cross-section of their bearing spanning structure of the box-girder type
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D2101/00—Material constitution of bridges
- E01D2101/20—Concrete, stone or stone-like material
- E01D2101/24—Concrete
- E01D2101/26—Concrete reinforced
- E01D2101/28—Concrete reinforced prestressed
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Abstract
The application relates to a construction method for dismantling a large-span prestressed cast-in-place box girder, which comprises the following steps of S1, dismantling an auxiliary structure, and dismantling bridge deck pavement and traffic facilities on the box girder; s2, cutting the expansion joint, breaking the concrete at the expansion joint of the box girder, and cutting off connecting steel bars, angle steel and bolts at the expansion joint; s3, cutting the box girder, firstly, erecting a dismantling support by adopting a disc buckle support, and jacking a bottom plate and wing plates at two sides of a concrete box girder box body by using the support; cutting the box girder by using a diamond wire saw; wherein the dismantling sequence of the box girder is as follows: symmetrically cutting wing plates on two sides, releasing and stretching web steel strands, cutting left webs, cutting box-type top plates, cutting right webs and cutting box chamber bottom plates; and S4, hanging and detaching the beam blocks, and adopting hoisting equipment to transport and abandon the cut beam blocks to a specified place. This application has and carries out safe quick effect of demolising to striding cast-in-place case roof beam of prestressing force greatly.
Description
Technical Field
The application relates to the technical field of building construction, in particular to a construction method for dismantling a long-span prestressed cast-in-place box girder.
Background
One of the box girder and bridge girder engineering center girders, referring to fig. 4, includes a top plate 11, a bottom plate 12 and two webs 13, the interior of which is hollow, and the top plate has wing plates 14 at both sides, similar to a box, so that it is named. According to the manufacturing method, the box girder is mainly divided into two types, namely a prestressed reinforced concrete box girder and a steel box girder. The prestressed reinforced concrete box girder is constructed on site, and transverse prestress is also arranged in some cases besides longitudinal prestress; the steel box girder is generally processed in a factory and then transported to a site for installation, and has an all-steel structure and a partially reinforced concrete pavement layer. The steel box girder is also called steel plate box girder, and is a common structural form of a large-span bridge. Generally used on bridges with large span.
Along with the rapid development of economy in China, the road traffic flow is rapidly increased, the use requirement and the bearing capacity requirement on the conventional road bridge structure are higher and higher, many bridge structures are too heavy under busy traffic, and some bridge structures exceed the design life; some dangerous bridges are caused by various reasons and are subjected to the conditions of reinforcement, reconstruction, dismantling and reconstruction. For cast-in-place box girder type bridges, the following methods are generally adopted for demolition: it is usually necessary to first consolidate the box girder and the pier stud, i.e. to pour a concrete structure on the top of the pier stud, to consolidate the box girder by using the bottom pier, the pier stud and the concrete structure, then to cut the whole block along the transverse extension direction of the bridge deck, and then to lift and remove the block.
The method for dismantling the bridge is only suitable for dismantling the bridge with smaller beam size and better box girder integrity, but the dismantling of the large-span prestressed cast-in-place box girder is often more complicated and is limited by large-scale equipment operation conditions, traffic conditions, high structural bearing capacity evaluation difficulty, dismantling equipment and operation environment limitations and other factors, the overall characteristics of bridge dismantling are high risk and complex structural secondary system conversion stress, if the beam bridge adopts the nondestructive cutting to completely lose the prestressed steel beam, secondary evaluation on the structural bearing capacity is needed, a reasonable temporary support system is arranged, when the size of the bridge box girder is larger, most people can select a form of completely expanding and cutting, the weight of a cutting block body of the box girder after the whole block cutting is larger from the broken end or the middle cutting of the box girder, the impact load of the lower temporary support is larger, and the impact force of the bridge is far larger than the self weight of the box girder, the supporting stability is influenced, and the technical problem of great potential safety hazard exists. Therefore, a dismantling construction method for a large-span prestressed cast-in-place box girder is urgently needed to be researched, and the box girder can be safely and quickly dismantled.
Disclosure of Invention
In order to safely and quickly remove the large-span prestressed cast-in-place box girder, the application provides a construction method for removing the large-span prestressed cast-in-place box girder.
The application provides a construction method for dismantling a large-span prestressed cast-in-place box girder, which adopts the following technical scheme: a construction method for dismantling a large-span prestressed cast-in-place box girder is characterized by comprising the following steps: comprises the following steps of (a) carrying out,
s1, dismantling the auxiliary structure, and dismantling the bridge deck pavement and traffic facilities on the box girder;
s2, cutting the expansion joint, breaking the concrete at the expansion joint of the box girder, and cutting off connecting steel bars, angle steel and bolts at the expansion joint;
s3, cutting the box girder, firstly, erecting a dismantling support by adopting a disc buckle support, and jacking a bottom plate and wing plates at two sides of a box body of the concrete box girder (1) by using the support; cutting the box girder by using a diamond wire saw; wherein the dismantling sequence of the box girder is as follows: symmetrically cutting wing plates on two sides, releasing and stretching web steel strands, cutting left webs, cutting box-type top plates, cutting right webs and cutting box chamber bottom plates;
and S4, hanging and detaching the beam blocks, and adopting hoisting equipment to transport and abandon the cut beam blocks to a specified place.
By adopting the technical scheme, when the box girder is dismantled, firstly, all the auxiliary structures on the box girder are dismantled, so that the influence of the auxiliary structures on the dismantling of the box girder is reduced, then, the expansion joints are dismantled easily, meanwhile, the expansion joints are weak points stressed during the dismantling, and need to be dismantled firstly, so that the potential safety hazard during the dismantling is reduced, workers can conveniently and sequentially and reasonably divide the dismantling sequence of the box girder, and then, the box girder dividing the dismantling sequence is cut in a step-by-step deloading and subsection relaxation mode; in the application, the wing plates are positioned at two sides of the box girder, so that the box girder is easy to dismantle, and the influence on the dismantling stability of the box girder is large when the box girder is dismantled, so that the wing plates in the box girder structure are firstly cut, the wing plates of the box girder are correspondingly dismantled when being dismantled, a mode of sequentially dismantling the other side after being dismantled is not adopted, otherwise, the girder body can be overturned and turned over, and the dismantling support bears the weight of the wing plates during dismantling, so that the impact force is reduced; after the wing plates are dismantled, the web plate steel stranded wires are expanded, so that the influence of sudden expansion of the steel stranded wires on the box girder when the web plates are dismantled can be reduced, and the potential safety hazard when the box girder is dismantled is further reduced; when the left web plate is cut, only the weight of the left web plate can impact the dismantling bracket, so that the impact force is reduced; when the box-type top plate is cut, the top plate can be directly lifted off by using lifting equipment, and the impact on a dismantling support can be reduced to the minimum; when the right web plate is cut, only the weight of the right web plate can impact the dismantling bracket, so that the impact force is reduced; finally, the bottom plate of the box chamber is cut, only the weight of the residual bottom plate can impact the dismantling support, and the impact on the dismantling support during the dismantling of the box girder is reduced to the maximum extent; above-mentioned pterygoid lamina, web and roof demolish the in-process, the bottom plate of case roof beam all the time with the main part interconnect of bridge, most weight of case roof beam supports by self stability promptly, and then reduces the impact force that supports the support body to the case roof beam downside when the case roof beam demolishs to reduce the potential safety hazard when the case roof beam demolishs, realize safe quick the purpose of demolishing the case roof beam.
Preferably, in the step S3, the two side wing plates are respectively cut into multiple sections of wing plate cutting units, and then each section of wing plate cutting unit is removed, so that each section of wing plate cutting unit meets the requirement of the bearing capacity of the hoisting equipment.
Through adopting above-mentioned technical scheme, divide into the multistage and cut the removal with both sides pterygoid lamina according to the bearing capacity demand of demolising support and lifting device to further reduce the impact load to demolising the support when the case roof beam is demolishd, reduce the potential safety hazard.
Preferably, in step S3, the removing sequence of the multi-segment wing cutting unit is to detach the wing from its two ends to the middle simultaneously, and simultaneously, form lifting holes at 0.3m-1.0m around the center of gravity of each wing segment, where the number of the lifting holes is not less than four.
By adopting the technical scheme, construction is carried out from two ends to the middle part of the wing plate, two working surfaces are formed for flow operation, continuous cutting and hoisting are realized, hoisting holes are drilled at the positions of 0.3-1.0 m around the gravity center of each wing plate section, and the number of the hoisting holes is not less than four, so that hoisting equipment can hoist the wing plate more stably.
Preferably, in the step S3, in the left-side web cutting, the left-side web is divided into a plurality of left-side web cutting units, and then the left-side web cutting units are sequentially cut and removed at one end of the box girder along the longitudinal direction of the box girder.
Through adopting above-mentioned technical scheme, divide into the multistage and cut the removal with the left side web according to the bearing capacity demand of demolising support and lifting device to further reduce the impact load to demolising the support when the case roof beam is demolishd, reduce the potential safety hazard.
Preferably, in the box type roof cutting of step S3, the roof is divided into a plurality of roof cutting units, and then the roof cutting units are sequentially cut and removed at one end of the box girder in the longitudinal direction of the box girder.
Through adopting above-mentioned technical scheme, divide into the multistage and cut the removal with the roof according to the bearing capacity demand of demolising support and lifting device to further reduce the impact load to demolising the support when the case roof beam is demolishd, reduce the potential safety hazard.
Preferably, in the right web cutting of step S3, the right web is divided into a plurality of right web cutting units, and then the right web cutting units are sequentially cut and removed at one end of the box girder along the longitudinal direction of the box girder.
Through adopting above-mentioned technical scheme, divide into the multistage and cut the removal with the right side web according to the bearing capacity demand of demolising support and lifting device to further reduce the impact load to demolising the support when the case roof beam is demolishd, reduce the potential safety hazard.
Preferably, in the cutting of the bottom plate of the cabinet in the step S3, the bottom plate is divided into a plurality of bottom plate cutting units, and then the bottom plate cutting units are sequentially cut and removed at one end of the box girder along the longitudinal direction of the box girder.
Through adopting above-mentioned technical scheme, divide into the multistage and cut the removal with the case room bottom plate according to the bearing capacity demand of demolising support and lifting device, only remain box bottom plate this moment and can produce impact load to demolising the support to further reduce the impact load to demolising the support when the case roof beam is demolishd, reduce the potential safety hazard. In addition, in order to further improve the dismantling efficiency of the bottom plate, in addition to cutting and dismantling the bottom plate by blocks along the longitudinal direction of the box girder at one end of the box girder, workers can also dismantle the bottom plate from the midspan of the bottom plate to the two ends of the bottom plate, or synchronously dismantle the bottom plate from the midspan to the two ends and from the two ends to the midspan.
Preferably, in the step S3 of cutting the left web and the right web, the cutting position extends a distance from the upper end and the lower end of the web to the top plate and the bottom plate, the extending distance satisfies that the center of gravity of each section of left web cutting unit or right web cutting unit is located at the top plate position, and each section of left web cutting unit or right web cutting unit satisfies the requirement of the load-bearing capacity of the hoisting equipment, then, hoisting holes are drilled at a position of 0.3m-1.0m around the center of gravity of the left web cutting unit or right web cutting unit, and the number of the hoisting holes is not less than four.
Through adopting above-mentioned technical scheme, can demolish partial roof and bottom plate in step when demolising the web, when reducing the web and demolising the degree of difficulty, still can make the split of the whole weight of case roof beam more even to it demolishs degree of difficulty and potential safety hazard to reduce the case roof beam.
Preferably, in step S3, the disc buckle support is a full hall disc buckle scaffold, the temporary support is made of steel pipe with a diameter of 60.3mm and a wall thickness of 3.25mm, and is made of Q345 steel, a stress point of the temporary support falls on a lower bridge capping beam, the temporarily supported bailey beam is placed at the bottom of the support, a double-row single-group unreinforced bailey beam is used as a bearing sleeper beam on the existing bridge capping beam, a bailey longitudinal beam is directly placed on the sleeper beam and serves as a longitudinal bearing main beam, the longitudinal bearing main beam is a double-row single-group reinforced bailey beam, the transverse clear distance of the bailey beam group is 63cm, and # 12 h-section steel is laid above the longitudinal bailey beam.
By adopting the technical scheme, the construction of erecting the temporary supports by the full-scale plate buckle scaffold is convenient and quick, and meanwhile, the size of the steel pipe is 60.3mm in diameter, the wall thickness is 3.25mm, and the material is Q345 steel, so that the temporary supports can support the box girder more stably; the stress point of the temporary support falls on the lower bridge capping beam, so that the influence of the temporary support on the road on the lower side of the box girder can be further reduced; 12# I-steel can be with bailey frame even, makes every row bailey frame atress comparatively balanced, when demolising the case roof beam, can wholly provide stable support to the case roof beam to reduce the potential safety hazard when the case roof beam is demolishd.
Preferably, in step S3, the construction process of cutting the main beam box by using the diamond wire saw includes: 1) determining the position of a cutting section, paying off the full-bridge cutting section, and then vertically drilling at the position of the cutting line; 2) installing and fixing a guide wheel; 3) fixing the wire saw; 4) installing a diamond rope, and enabling the diamond rope to penetrate through the drill hole to be installed on the guide wheel and the wire saw; 5) and cutting.
Through adopting above-mentioned technical scheme, can install the rope saw machine on the case roof beam fast and the accuracy cuts the case roof beam to make the cutting of case roof beam go on in order.
To sum up, the application comprises the following beneficial technical effects:
1. when the box girder is dismantled, firstly, all the auxiliary structures on the box girder are dismantled, so that the influence of the auxiliary structures on the dismantling of the box girder is reduced, then, the expansion joints are dismantled, the expansion joints are easy to dismantle, meanwhile, the expansion joints are the weak points of stress during the dismantling, and the dismantling is required firstly, so that the potential safety hazard during the dismantling is reduced, workers can reasonably divide the dismantling sequence of the box girder, and then, the box girder with the dismantling sequence is cut in a step-by-step deloading and section-by-section relaxation mode, so that the impact force on a support frame body at the lower side of the box girder is reduced during the dismantling of the box girder, the potential safety hazard during the dismantling of the box girder is reduced, and the aim of safely and quickly dismantling the box girder is fulfilled;
2. the scaffold is detained to full hall dish sets up and demolishs comparatively convenient and fast of support construction, adopts the steel pipe size to be diameter 60.3mm simultaneously, and wall thickness 3.25mm, the material is Q345 steel for support to the case roof beam more stable temporarily, when demolising the case roof beam, can wholly provide stable support to the case roof beam, thereby reduces the potential safety hazard when the case roof beam is demolishd.
Drawings
FIG. 1 is a process flow diagram of an embodiment of the present application.
Fig. 2 is a longitudinal section schematic view of a dismantling support of the embodiment of the application after being erected on the lower side of a box girder to be dismantled.
Fig. 3 is a schematic cross-sectional view of a reinforcing beret beam erection.
FIG. 4 is a schematic cross-sectional view of a box girder to be removed according to an embodiment of the present application.
FIG. 5 is a schematic view of a cutting position line and a hanging and detaching sequence of the box girder according to the embodiment of the present application.
FIG. 6 is a schematic view of a left-side web lifting and dismounting sequence of the box girder with two side wing plates removed according to the embodiment of the application.
FIG. 7 is a schematic view of a top plate hanging-dismounting sequence of the box girder with the left web removed according to the embodiment of the application.
FIG. 8 is a schematic view of a right-side web dismounting sequence of the box girder with the top plate removed according to the embodiment of the application.
FIG. 9 is a schematic view of the bottom plate hanging and detaching sequence of the box girder with the right web detached according to the embodiment of the application.
In the figure, 1, a box girder; 11. a top plate; 111-117 and a top plate cutting unit; 12. a base plate; 121-127, a bottom plate cutting unit; 13. a web; 131-134 and a left web cutting unit; 135-138, a right web cutting unit; 14. a wing plate; 141-147, a wing plate cutting unit; 2. square wood; 3. i-shaped steel; 4. reinforcing the Bailey beam; 5. and (5) removing the bracket.
Detailed Description
The present application is described in further detail below with reference to figures 1-9.
Referring to fig. 1 and 2, for the embodiment of the application, a construction method for dismantling a long-span prestressed cast-in-place box girder is disclosed, which comprises the following steps:
s1, construction preparation:
1. planning a field, designating a crushing area, and establishing a safety channel;
2. safety construction, namely, making safety warning, indication and marks according to the requirements of double marks;
3. the construction water adopts river water;
4. preparing for electrifying according to the electricity consumption of the mechanical equipment;
5. planning, preparing and trying out construction machinery, construction materials and construction tools in advance;
6. carrying out construction safety education and detailed technical background for workers;
7. the truck cranes and other components are stacked in sequence; and carrying out flaw detection test on key stressed members such as the steel pipe main girder and the like, replacing and welding unqualified structures.
S2, dismantling the auxiliary structure, and dismantling the bridge deck pavement and traffic facilities on the box girder 1; the bridge deck pavement and the sidewalk are both transported outside after chiseling and crushing on the bridge deck by manual matching machinery. The crusher mainly comprises an excavator, an air pick, a breaking hammer and the like. The breaking hammer is used for breaking large-area concrete blocks; the excavator is used for paving, excavating and loading broken blocks into a truck; the pneumatic pick is used for removing small-area concrete blocks; the anti-collision guardrail is disassembled by gas cutting, then the guardrail and the outer side hanging plate concrete structure are disassembled by a breaking hammer, and finally the guardrail is loaded by an excavator and transported outside.
And S3, cutting the expansion joint, breaking the concrete pavement on two sides of the expansion joint of the extension box girder 1 by using an artificial pneumatic pick, and cutting off the connecting steel bars, the angle steel and the bolts by using oxygen and acetylene.
And S3, cutting the main box girder 1, and organizing bridge dismantling personnel to perform completion picture review on the old bridge box girder 1, carefully reading the pictures, knowing the basic outline of the old bridge and the engineering quantity of each part of member, and mastering the structure and stress characteristics of the bridge. And arranging measuring personnel to recheck the position and the size of the actual structure of the finished drawing and popping the positions of the webs 13 and the cross beams on the bridge surface. And simultaneously carrying out stability analysis, perforated section stress analysis, checking calculation of the bearing capacity of the upper part structure of the bridge, checking calculation of the bearing capacity of the lower part of the bridge and the like on the bridge under each working condition, and determining the dismantling sequence of the box girder 1 according to the checking calculation result.
Referring to fig. 2 and 3, firstly, a disc buckle support is adopted to set up a dismantling support 5, a full hall disc buckle scaffold is adopted to set up a temporary support, the size of a steel pipe is 60.3mm in diameter, the wall thickness is 3.25mm, the material is Q345 steel, the stress point of the temporary support falls on a lower bridge cover beam, a temporarily supported Bailey beam is placed at the bottom of the support, a double-row single-group unreinforced Bailey beam 4 is used as a bearing sleeper beam on the existing bridge cover beam, the Bailey longitudinal beam is directly placed on the sleeper beam and is used as a longitudinal bearing main beam, the longitudinal bearing main beam is a double-row single-group reinforced Bailey beam, the Bailey beam group is arranged with the transverse clear distance of 63cm, 12# I-steel 3 is laid above the longitudinal Bailey beam, and the support body supports a box bottom plate 12 of a concrete box beam 1 and wing plates 14 on two sides; the specific operation is as follows:
(1) measuring line
And according to the design scheme and the plane arrangement diagram, the total station and the steel ruler are adopted to release the accurate position of the beam, so that the beam is ensured to be completely positioned above the bearing wall.
(2) Bailey beam construction
The sleeper beam adopts a double-row domestic non-reinforced Bailey beam 4(3 multiplied by 1.5 m). Firstly, the bailey frames are assembled on the ground and connected in groups. The longitudinal beam adopts a reinforced Bailey beam 4, and the Bailey frame position is marked on the transverse bridge sleeper beam by red paint according to the design position. And hoisting the connected bailey frames in place by using a truck crane according to the sequence of the middle part and the two sides.
The longitudinal section is arranged according to the concrete structure of the box girder 1, single-layer double-group reinforced Bailey sheets with the net spacing of 63cm are adopted, 12# I-steel 3 is laid above the Bailey sheets, and the Bailey sheets are connected into a whole in a targeted manner, so that the stress of each row of Bailey sheets is balanced.
When the single-group Bailey frames are hoisted, two hoisting points are required to be arranged and distributed at equal intervals, and the balance of the Bailey beams in the hoisting process is kept so as to avoid the generation of torsional stress in the hoisting process. And paving a steel plate after the bailey frames are completely erected.
(3) Support erection
a. And the positions of the center line and the side line of the bridge are determined by snapping lines on the steel plate so as to ensure that the support frame is erected and does not deviate from the use range.
b. The bottom of the supporting frame adopts an adjustable base, and the height range is adjusted to be 550mm so as to control the height error of the base plane. And (5) installing a vertical rod, and installing a cross rod layer by layer and fastening the cross rod with the vertical rod.
c. The step pitch of the cross rods of the support is 150cm, the transverse bridge pitch is respectively 120cm, 90cm and 150cm according to a box type structure, and the longitudinal bridge span is respectively 90cm and 150 cm. And 48 steel pipes and the support are adopted around the pier stud for connection, reinforcement and column embracing, so that the overall stability of the support is ensured.
d. A steel pipe with the diameter of 48mm multiplied by 3.5mm is provided with a horizontal cross brace, and the steel pipe is firmly buckled with a disc buckle horizontal rod by a fastener. The cross-bracing steel pipes are lapped, the lapping length is not less than 1.0m, and the positions, away from the rod ends, of the cross-bracing steel pipes are fixed by 2 rotary fasteners and not less than 100mm respectively; when the vertical rod can not be buckled, the vertical rod is buckled with the cross rod; the binding surface of the fastener and the steel pipe must be strictly shaped to ensure good contact with the steel pipe when being fastened, and when the fastener clamps the steel pipe, the minimum distance of the opening is not less than 5 mm; the tightening torque of the fastener is 40-65 N.m; the scissors below the wing plate 14 are fully supported, the distance between the scissors below the box chamber is not more than 4.5m, one horizontal pull rod is arranged every 4.5m, and the scissors are processed at 4.5m below 4.5 m.
e. The top of the support adopts an adjustable jacking to control the elevation of the top of the support and ensure the installation precision of the support.
f. And a 12# I-steel 3 cross beam is arranged above the jacking of the wing plate 14, and the longitudinal beam is 10 multiplied by 15cm square timber and 220 cm. The arrangement direction of the I-shaped steel 3 is consistent with the cutting direction. In the field construction, the square timber 2 or the I-steel 3 can be properly disconnected to leave a slit gap in consideration of cutting requirements. 12# I-steel 3 is adopted above the top support of the box chamber, and the cutting position can be disconnected in order to avoid cutting the I-steel 3 during cutting. The reasonable installation of the square timber 2 or the I-steel 3 plays an obvious role in later cutting and reducing the impact load after the beam falls.
g. The waterproof color stripe cloth is laid below the temporary support, the geotextile is laid on the color stripe cloth, a 24 cm-high water retaining wall is bricked around the color stripe cloth, and a water pumping vehicle is adopted for timing extraction.
(4) Preparing truck crane
And (4) hoisting and unloading the beam blocks by using a truck crane, wherein the crane is a 300t crane. The hoisting weight is 300 tons, the working radius is 25 meters, the length of the main arm is 30m, and the hoisting weight is 28 tons; when the working radius is 21 meters and a main arm with the length of 52 meters is adopted, the weight can be lifted by 24.2 tons; when the working radius is 18 meters and a main arm with the length of 34 meters is adopted, the crane can lift 42 tons, and the installation condition of the crane meets the requirement. The position of the crane is comprehensively considered according to the field condition and the lifting performance parameter table thereof, and the minimum working radius of the crane is ensured.
(5) And cutting the main beam box body by adopting a diamond wire saw
The construction process for cutting the main beam box by the diamond wire saw comprises the following steps:
1) determining the position of a cutting section, paying off the full-bridge cutting section, vertically drilling at the position of a cutting line, observing the drilling position under the bridge, wherein the drilling position is located in the middle of two rows of scaffolds as far as possible, and if the horizontal prestressed steel bars are touched during drilling, the longitudinal deviation can be properly carried out, steel strands are avoided, 4 hoisting holes with the diameter of phi 108 are drilled in each segment block, and the drilling position is selected at the central position which can ensure the relative balance of the hoisting blocks during hoisting; and determining the cutting weight according to the shape of the cut part and the conditions of a construction site, partitioning the cut part into blocks, and constructing by adopting a vertical cutting mode or a horizontal cutting mode.
2) Installing and fixing a guide wheel; a chain ring is adopted to wrap a cutting area, a cutting machine and a guide wheel are installed, a main foot stand and an auxiliary foot stand of the rope saw are fixed by an M16 chemical anchor bolt for synchronously cutting, the guide wheel is required to be installed stably, the edge of the wheel is required to be aligned with the central line of a rope threading hole, the effective cutting speed of the cutting surface is ensured, and the installation precision requirement is strictly executed.
3) Fixing the wire saw; and part of the box girder 1 is cut by a chain type cutting machine, and each cutting surface and the anchor head are staggered by a certain distance.
4) Installing a diamond rope, and enabling the diamond rope to penetrate through the drill hole to be installed on the guide wheel and the wire saw; winding diamond ropes on the driving wheel and the auxiliary wheel according to a determined cutting form in a certain sequence, and paying attention to the fact that the direction of the ropes is consistent with the driving direction of the driving wheel; according to the field situation, the connection of related pipelines such as water, electricity and mechanical equipment is required to be correct, standard and relatively centralized, and the wiring arrangement strictly executes safe operation rules so as to prevent accident potential caused by multiple machines, multiple people, disordered arrangement and disordered arrangement of auxiliary equipment and materials. In the rope cutting process, the front of the rope moving direction is protected by a safety guard rail, and a safety mark is arranged in a certain area to prompt pedestrians not to enter a construction operation area. In use, the use direction of the diamond wire saw needs to be correctly distinguished. The diamond wire saw moves forward in the arrow direction and can not cut in the opposite direction, so that the front end and the rear end of the bead string are prevented from generating conicity, and the normal use of the diamond wire saw is ensured. The connection operation method of the diamond wire saw comprises the following steps:
a. the length of the two exposed steel wire ropes is equal to the length of the joint.
b. The steel wire ropes with two exposed ends are inserted into the steel joint, and the joint and the adjacent beads should have no gap.
c. And the special hydraulic pliers for the diamond wire saw are adopted to tightly press the joint buckle. When in buckling, the middle part of the joint is firstly placed in a hydraulic clamp for buckling once when the joint rotates 90 degrees; then placing the two ends of the joint in hydraulic pliers for sequential buckling; finally, the middle part of the joint is placed in hydraulic pressure again for buckling and pressing;
d. and (4) checking the joint after buckling, and removing the flash and the burr completely by using an angle grinder and the like.
5) Cutting, starting the electric motor, adjusting the lifting tension of the driving wheel through the control panel to ensure that the diamond rope is properly tightened, supplying circulating cooling water, and then starting the other electric motor to drive the driving wheel to drive the diamond rope to rotate for cutting. The stability of the base is closely observed in the cutting process, the deviation of the guide wheel is adjusted at any time to ensure that the cutting ropes are in the same plane, the cutting parameters are adjusted by operating the control disc in the cutting process to ensure that the running linear speed of the diamond ropes is about 20m/s, and on the other hand, enough flushing liquid is ensured in the cutting process to ensure the cooling of the diamond ropes and take away the ground powder scraps. The cutting operation has stable speed, stable parameters and stable equipment.
Referring to fig. 4 to 9, the box girder 1 is cut in the order of: symmetrically cutting the wing plates 14 on the two sides, respectively cutting the wing plates 14 on the two sides into a plurality of sections of wing plate cutting units 141-147, dividing the wing plates 14 into seven sections along the longitudinal direction of the wing plates according to the bearing capacity of the truck crane and the dismantling support 5 and the uniform division of the whole weight of the box girder 1, wherein each section of wing plate cutting unit 141-147 meets the requirement of the bearing capacity of hoisting equipment; the sequence of removal of the multi-segment wing panel 14 units is: the wing plates 14 are synchronously removed from two ends to the middle, namely the wing plate cutting units 141 and 147 move towards the wing plate cutting units 144, and meanwhile, four lifting holes with the diameter of phi 108 are drilled at the position of 0.3m-1.0m around the gravity center of each section of the wing plate 14, so that the lifting of the wing plate 14 by the truck crane is more stable, and meanwhile, two working surfaces are adopted for water flowing operation, and continuous cutting and lifting are realized.
14 cutting of pterygoid lamina is accomplished the back, 13 steel strands of web are put first, carry out the cutting of left side web 13 afterwards, divide into four sections left side web cutting units 131 ~ 134 with left side web 13, and every section left side web cutting unit 131 ~ 134 satisfies hoisting equipment bearing capacity demand, longitudinally cut left side web cutting unit 131 ~ 134 according to the order in proper order with left side web cutting unit 131 ~ 134 at the one end of case roof beam 1 afterwards, demolish, thereby when left side web 13 cuts in proper order, web 13 that is not cut still depends on case roof beam 1, further support case roof beam 1 with the stability of bridge self, to the impact load who demolishs support 5 when reducing case roof beam 1 and demolishs, reduce the potential safety hazard. When the left web 13 is cut, the cutting position extends to the top plate 11 and the bottom plate 12 from the upper end and the lower end of the web 13 by a distance, the extending distance meets the requirement that the gravity center of each section of left web cutting unit 131-134 is located at the position of the top plate 11, then four hoisting holes with phi 108 are drilled at the position of 0.3m-1.0m around the gravity center of the left web 13 cutting unit, and a truck crane is adopted to hoist the hoisting holes.
After the left web 13 is cut, the box-type top plate 11 is cut, the top plate 11 is divided into seven sections of top plate cutting units 111-117, four lifting holes of phi 108 are drilled at the position of 0.3-1.0 m around the gravity center of each section of top plate cutting unit 111-117, a truck crane is adopted to lift the lifting holes, and then the top plate cutting units 111-117 are sequentially cut and detached at one end of the box girder 1 along the longitudinal direction of the box girder 1.
After the box-type top plate 11 is cut, the right web plate 13 is divided into four sections of right web plate cutting units 135-138, the right web plate cutting units 135-138 of each section meet the bearing capacity requirement of hoisting equipment, and then the right web plate cutting units 135-138 are sequentially cut and removed in sequence at one end of the box girder 1 along the longitudinal direction of the box girder 1. When the right web 13 is cut, the cutting position extends to the direction of the top plate 11 and the bottom plate 12 for a distance from the upper end and the lower end of the web 13, the extending distance meets the requirement that the center of gravity of each section of right web 13 cutting unit is located at the position of the top plate 11, then four hoisting holes with phi 108 are drilled at the position of 0.3m-1.0m around the center of gravity of the right web cutting units 135-138, and a truck crane is adopted to hoist the hoisting holes.
After the right web 13 is cut, finally, the box chamber bottom plate 12 is cut, the bottom plate 12 is divided into seven sections of bottom plate cutting units 121-127, each section of bottom plate cutting unit 121-127 meets the bearing capacity requirement of hoisting equipment, then, the bottom plate cutting units 121-127 are sequentially cut and removed along the longitudinal direction of the box beam 1 at one end of the box beam 1, only the box bottom plate 12 at the moment can generate impact load on the removal support 5, so that the impact load on the removal support 5 during the removal of the box beam 1 is further reduced, the potential safety hazard is reduced to the minimum, in order to further improve the removal efficiency of the bottom plate 12, the bottom plate 12 is cut and removed in blocks along the longitudinal direction of the box beam 1, a worker can remove the bottom plate 12 from the midspan to the two ends of the bottom plate 12, and can also remove the bottom plate from the midspan to the two ends and from the midspan synchronously.
And S4, hanging and detaching the beam blocks, hanging the beam blocks obtained by cutting the box girder 1 on a flat-bed transport vehicle through a truck crane, and transporting the beam blocks to a digestion site for subsequent crushing treatment. The position of the crane should be comprehensively considered according to the field condition and the lifting performance parameter table thereof.
Selection of steel wire rope
And selecting a steel wire rope according to the maximum weight of the removed beam slab, and selecting the steel wire rope which is called important use steel wire rope (GB8918-2006) and meets the construction safety requirement of 6-8 times of the safety coefficient K.
According to the calculation of the maximum weight of the cutting block of 51.1 tons, a bottom-pocket hoisting method is adopted, each section of steel wire rope needs to bear 12.78t of vertical tension, the included angle between the steel wire rope and the horizontal plane is calculated according to 70 degrees, and the dynamic load coefficient K is 1.1. Then the stress of each steel wire rope sling is as follows:
when the beam hanging plate is used, a steel wire rope with the tensile strength of 1870MPa, the diameter of 42.0mm and 6 multiplied by 37 strands is selected, and the important purpose steel wire rope (GB8918-2006) is found that the breaking tension is 1170KN, and the construction safety requirement of 6 to 8 times specified by the safety coefficient K is met when the single steel wire rope bears the tension n which is 117/14.95 which is 7.83 times.
The implementation principle of the dismantling construction process of the box girder 1 in the embodiment of the application is as follows: when the box girder 1 is dismantled, firstly, all the auxiliary structures on the box girder 1 are dismantled, so that the influence of the auxiliary structures on the dismantling of the box girder 1 is reduced, then, the expansion joints are dismantled easily, meanwhile, the expansion joints are weak points stressed during the dismantling, and need to be dismantled firstly, so that the potential safety hazard during the dismantling is reduced, and workers can conveniently and orderly divide the dismantling sequence of the box girder 1 into the steps of firstly cutting the wing plates 14 on the two sides, cutting the web plate 13 on the left side, then cutting the box top plate 11, then cutting the web plate 13 on the right side, and finally cutting the box chamber bottom plate 12; adopt step by step to deload the segmentation and put the mode of opening and cut case roof beam 1, when reducible case roof beam 1 demolishs, to the impact force of 1 downside support body of case roof beam to promote the potential safety hazard when case roof beam 1 demolishs, reduce the influence to the surrounding environment simultaneously, and then safe quick demolishs case roof beam 1, reduces the influence to all ring edge borders simultaneously.
The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.
Claims (10)
1. A construction method for dismantling a large-span prestressed cast-in-place box girder is characterized by comprising the following steps: comprises the following steps of (a) carrying out,
s1, dismantling the auxiliary structure, and dismantling the bridge deck pavement and traffic facilities on the box girder (1);
s2, cutting the expansion joint, breaking the concrete at the expansion joint of the box girder (1), and cutting off connecting steel bars, angle steel and bolts at the expansion joint;
s3, cutting the box girder (1), firstly, erecting a dismantling support (5) by adopting a disc buckle support, and jacking a bottom plate (12) and wing plates (14) at two sides of a box body of the concrete box girder (1) (1) by using the support; cutting the box girder (1) by a diamond wire saw; wherein the dismantling sequence of the box girder (1) is as follows: symmetrically cutting wing plates (14) on two sides, spreading steel strands on a web plate (13), cutting a left web plate (13), cutting a box-type top plate (11), cutting a right web plate (13) and cutting a box chamber bottom plate (12);
and S4, hanging and detaching the beam blocks, and adopting hoisting equipment to transport and abandon the cut beam blocks to a specified place.
2. The construction method for dismantling the long-span prestressed cast-in-place box girder according to claim 1, is characterized in that: in the step S3, the wing plates (14) on the two sides are respectively cut into a plurality of sections of wing plate cutting units (141-147), then each section of wing plate cutting unit (141-147) is removed, and each section of wing plate cutting unit (141-147) meets the requirement of the bearing capacity of the hoisting equipment.
3. The construction method for dismantling the long-span prestressed cast-in-place box girder according to claim 2, is characterized in that: in the step S3, the multi-section wing plate cutting units (141-147) are removed synchronously from two ends to the middle of the wing plate (14), and meanwhile, hoisting holes are drilled at the position of 0.3m-1.0m around the gravity center of each wing plate cutting unit (141-147), wherein the number of the hoisting holes is not less than four.
4. The construction method for dismantling the long-span prestressed cast-in-place box girder according to claim 3, is characterized in that: in the step S3 of cutting the left web (13), the left web (13) is divided into a plurality of sections of left web cutting units (131-134), and then the left web cutting units (131-134) are sequentially cut and removed at one end of the box girder (1) along the longitudinal direction of the box girder (1).
5. The construction method for dismantling the long-span prestressed cast-in-place box girder according to claim 4, is characterized in that: in the cutting of the box type roof (11) in the step S3, the roof (11) is divided into a plurality of sections of roof cutting units (111-117), and then the roof cutting units (111-117) are sequentially cut and removed along the longitudinal direction of the box girder (1) at one end of the box girder (1).
6. The construction method for dismantling the long-span prestressed cast-in-place box girder according to claim 5, is characterized in that: in the step S3 of cutting the right web (13), the right web (13) is divided into a plurality of sections of right web cutting units (135-138), and then the right web cutting units (135-138) are sequentially cut and removed along the longitudinal direction of the box girder (1) at one end of the box girder (1).
7. The construction method for dismantling the long-span prestressed cast-in-place box girder according to claim 6, is characterized in that: in the cutting of the box chamber bottom plate (12) in the step S3, the bottom plate (12) is divided into a plurality of sections of bottom plate cutting units (121-127), and then the bottom plate cutting units (121-127) are sequentially cut and removed along the longitudinal direction of the box beam (1) at one end of the box beam (1).
8. The construction method for dismantling the long-span prestressed cast-in-place box girder according to claim 7, is characterized in that: s3, in the cutting of the left web (13) and the right web (13), one end of the cutting position extends from the upper end and the lower end of the web (13) to the direction of the top plate (11) and the direction of the bottom plate (12), the extending distance meets the requirement that the gravity center of each section of left web cutting unit (131-134) or right web cutting unit (135-138) is located at the position of the top plate (11), the bearing capacity requirement of hoisting equipment is met by each section of left web cutting unit (131-134) or right web cutting unit (135-138), then hoisting holes are drilled at the position of 0.3m-1.0m around the gravity center of the left web cutting unit (131-134) or the right web cutting unit (135-138), and the number of the hoisting holes is not less than four.
9. The construction method for dismantling the long-span prestressed cast-in-place box girder according to claim 7, is characterized in that: in the step S3, a full hall disc buckle scaffold is adopted for a disc buckle support to set up a temporary support, the temporary support is made of steel pipes with the diameter of 60.3mm and the wall thickness of 3.25mm, the material is Q345 steel, the stress point of the temporary support falls on a lower bridge cover beam, a Bailey beam of the temporary support is placed at the bottom of the support, a double-row single-group unreinforced Bailey beam (4) is used as a bearing sleeper beam on the existing bridge cover beam, the Bailey longitudinal beam is directly placed on the sleeper beam and is used as a longitudinal bearing main beam, the longitudinal bearing main beam is a double-row single-group reinforced Bailey beam, the Bailey beam group is arranged at the transverse clear distance of 63cm, and 12# I-steel (3) is laid above the longitudinal Bailey beam.
10. The construction method for dismantling the long-span prestressed cast-in-place box girder according to claim 9, is characterized in that: in step S3, the construction process for cutting the main beam box by the diamond wire saw comprises: 1) determining the position of a cutting section, paying off the full-bridge cutting section, and then vertically drilling at the position of the cutting line; 2) installing and fixing a guide wheel; 3) fixing the wire saw; 4) installing a diamond rope, and enabling the diamond rope to penetrate through the drill hole to be installed on the guide wheel and the wire saw; 5) and cutting.
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| CN202110524440.7A CN113235467A (en) | 2021-05-13 | 2021-05-13 | Construction method for dismantling large-span prestressed cast-in-place box girder |
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| CN202110524440.7A CN113235467A (en) | 2021-05-13 | 2021-05-13 | Construction method for dismantling large-span prestressed cast-in-place box girder |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113774821A (en) * | 2021-08-28 | 2021-12-10 | 中交一公局集团有限公司 | Bridge disassembling process |
| CN113774822A (en) * | 2021-09-15 | 2021-12-10 | 中交二航局第三工程有限公司 | Dismantling method of old reinforced concrete bridge |
| CN114263129A (en) * | 2021-12-31 | 2022-04-01 | 宁波市政工程建设集团股份有限公司 | Dismantling construction method for bridge superstructure |
| CN114541286A (en) * | 2021-12-31 | 2022-05-27 | 宁波市政工程建设集团股份有限公司 | Segmented block dismantling construction method for cast-in-situ prestressed box girder |
| CN114687300A (en) * | 2022-04-08 | 2022-07-01 | 中铁大桥局集团有限公司 | Maintenance method and maintenance system for box girder above transformer |
| CN114700598A (en) * | 2022-04-13 | 2022-07-05 | 中铁物总资源科技有限公司 | Method for cutting side plates and end plates of railway scrapped wagon carriage |
| CN114960482A (en) * | 2022-06-20 | 2022-08-30 | 保利长大工程有限公司 | Method for safely and efficiently removing external prestress |
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- 2021-05-13 CN CN202110524440.7A patent/CN113235467A/en not_active Withdrawn
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113774821A (en) * | 2021-08-28 | 2021-12-10 | 中交一公局集团有限公司 | Bridge disassembling process |
| CN113774822A (en) * | 2021-09-15 | 2021-12-10 | 中交二航局第三工程有限公司 | Dismantling method of old reinforced concrete bridge |
| CN114263129A (en) * | 2021-12-31 | 2022-04-01 | 宁波市政工程建设集团股份有限公司 | Dismantling construction method for bridge superstructure |
| CN114541286A (en) * | 2021-12-31 | 2022-05-27 | 宁波市政工程建设集团股份有限公司 | Segmented block dismantling construction method for cast-in-situ prestressed box girder |
| CN114541286B (en) * | 2021-12-31 | 2023-09-05 | 宁波市政工程建设集团股份有限公司 | Sectional block dismantling construction method for cast-in-situ prestressed box girder |
| CN114263129B (en) * | 2021-12-31 | 2023-09-05 | 宁波市政工程建设集团股份有限公司 | Bridge superstructure dismantling construction method |
| CN114687300A (en) * | 2022-04-08 | 2022-07-01 | 中铁大桥局集团有限公司 | Maintenance method and maintenance system for box girder above transformer |
| CN114700598A (en) * | 2022-04-13 | 2022-07-05 | 中铁物总资源科技有限公司 | Method for cutting side plates and end plates of railway scrapped wagon carriage |
| CN114960482A (en) * | 2022-06-20 | 2022-08-30 | 保利长大工程有限公司 | Method for safely and efficiently removing external prestress |
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