CN111979935A - Dismantling construction method for bridge superstructure - Google Patents
Dismantling construction method for bridge superstructure Download PDFInfo
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Abstract
The invention discloses a demolition construction method of a bridge superstructure, which mainly comprises the steps of demolition preparation, construction safety containment, demolition of a bridge deck anti-collision fence, demolition of a bridge deck, demolition of a beam plate and site cleaning; the beam plate dismantling comprises main span full-hanging beam dismantling operation and half-hanging beam and T beam dismantling operation; the main span full-hanging beam dismantling operation and the half-hanging beam and T beam dismantling operation comprise the steps of removing longitudinal and transverse connections, taking beams, dropping beams and transporting beams; the demolition construction method is basically contrary to the installation flow of the bridge, and is convenient to master and implement; under the conditions that the construction boundary is limited and mechanical equipment and construction conditions are not available, the construction method is adopted to solve the problem of overall beam body dismantling, has small influence on operation, ensures construction safety and has certain popularization significance.
Description
Technical Field
The invention relates to the technical field of bridge construction, in particular to a dismantling construction method for a bridge superstructure.
Background
It is known that, in the construction engineering, based on reinforced concrete, in the engineering construction process, due to the problems of change or error of design function and construction quality, some poured concrete structures must be dismantled, the traditional method is manual chiseling or mechanical crushing, and more advanced is static crushing or blasting dismantling, but the methods are either low in efficiency or high in risk and generally have serious noise and pollution, and the methods can generate disturbance damage to qualified reserved structures in the dismantling process to different degrees, so that cracks are generated in reserved parts of concrete or separation of reinforcing steel bars from the concrete, and the quality requirements of the original design are difficult to meet.
For example, for bridges which cannot meet the modern traffic requirements or reach the design age, the bridge needs to be dismantled; in general, the bridge dismantling project has the advantages of normal traffic guarantee, short construction period, heavy task, high bridge dismantling difficulty and high construction safety requirement. When the bridge is dismantled, the stability of the structure should be ensured as much as possible in the dismantling process, and the bridge cannot be influenced by overlarge vibration, impact and the like.
For example, the Chinese patent application (publication number: CN111139752A) discloses a method for dismantling a T-shaped hanging beam in 2020, which mainly comprises the following steps: firstly, dismantling an auxiliary structure on a bridge deck and a wing wall on a hanging beam; selecting a hoisting scheme, and designing a hoisting hole and a cutting line by combining the hoisting scheme; thirdly, arranging hoisting equipment according to the hoisting point position determined by the hoisting scheme; cutting a panel and a beam body of the T-shaped hanging beam, and installing a balance weight adjusting water tank; and fifthly, conveying the cut T-shaped hanging beam to a specified place through hoisting equipment for crushing. However, the dismantling method mainly has the following problems: (1) a better construction environment is needed, and the construction is difficult to implement under the conditions of limited construction boundary (dense water network along the engineering, more farmlands, complex environmental overhead lines and the like), incomplete mechanical equipment and unavailable construction conditions; (2) the arrangement and safety of hoisting are not carefully considered, so that the construction capacity is easily wasted; the protection of the reserved part of the bridge is insufficient.
Disclosure of Invention
The invention aims to provide a dismantling construction method of a bridge superstructure, aiming at the problems in the prior art.
In order to achieve the purpose, the invention adopts the technical scheme that:
a demolition construction method of a bridge superstructure mainly comprises the steps of demolition preparation, construction safety containment, demolition of a bridge deck anti-collision fence, demolition of a bridge deck, demolition of beam plates and site cleaning; the beam plate dismantling comprises main span full-hanging beam dismantling operation and half-hanging beam and T beam dismantling operation; the main span full-hanging beam dismantling operation and the half-hanging beam and T beam dismantling operation comprise the following steps:
(1) and (3) removing the vertical and horizontal relation: removing continuous and wet joints and diaphragm concrete of the bridge deck between the beam bodies by using a gun chisel, and cutting off the reinforcing steel bars by using gas cutting;
(2) taking a beam: a bridge girder erection machine or a crane is adopted, and a steel wire rope or a lifting appliance is matched to bundle a girder and lift the girder body to be dismantled;
(3) beam falling and beam conveying: for the main span full-hanging beam, the main span full-hanging beam falls on a beam transporting flat car and is transported to a fixed place to be stacked and uniformly processed; and for the half-hanging beam and the T beam, the moved beam bodies fall on the air and land step by step, crushing is intensively carried out by adopting a cannon, and finally, clearing is carried to a specified place.
The demolition construction method of the bridge superstructure can demolish the main span full-hanging beam, the semi-hanging beam and the T beam of the bridge reasonably and quickly, has good safety, and does not interrupt all traffic of the line where the bridge is located; in consideration of actual conditions such as half-width traffic, simultaneous construction of multiple parts and the like, the operation is carried out in a mechanical dismantling mode, and the influence on the surrounding environment can be reduced as much as possible.
The demolition method adopted by the construction method is basically contrary to the installation flow of the bridge, and is convenient to master and implement; under the conditions of limited construction boundary, incomplete mechanical equipment and unavailable construction conditions, especially in narrow places with poor beam transportation conditions, the construction method is adopted to solve the problem of overall beam body dismantling, has small influence on operation, ensures construction safety and has certain popularization significance.
In addition, the construction method can reasonably control the demolition part, and can reserve and continue to use T-shaped box girders, pier capping girders and the like; and (3) storing the main span full-hanging beams, half-hanging beams and T beams which are dismantled in a classified manner and carrying out centralized treatment according to the use condition, wherein the half-hanging beams and the T beams are basically crushed and are not recycled, and are transported by using a dump truck after being uniformly stacked to a slag disposal site (a designated place) meeting the requirements of a local environmental protection department, so that the dispersion and pollution of construction waste are reduced.
Further, the demolition preparation comprises the process of determining a demolition overall principle and formulating a demolition overall scheme, construction areas are divided and numbered according to the span number of the bridge, the bridge is successively constructed according to a left frame and a right frame, and demolition sequences are as follows: the outer beams are firstly disassembled, and then the outer beams are disassembled piece by piece from outside to inside.
The bridge is dismantled according to the steps of the construction method, and the general principle that the bridge is safe, first, orderly constructed, balanced and symmetrical, and the whole is broken into parts from top to bottom can be carried out, so that the bridge is guaranteed to be dismantled safely and quickly.
Further, dismounting, mounting and hoisting safety calculation is required to be completed in the dismounting preparation step, the dismounting and mounting safety calculation mainly comprises beam dismounting weight calculation, hoisting machinery and hanger type selection, hoisting steel wire rope safety calculation and anti-overturning calculation, and simulation tests are carried out on corresponding ground before hoisting construction. The calculation can ensure the safety of construction on one hand, and on the other hand, can obtain reasonable arrangement modes of hoisting machinery, a hoisting tool and the like, avoids repeated adjustment in the construction process, and can improve the construction efficiency.
Further, the construction of the safety enclosure comprises arranging safety protection nets on two sides of the bridge, and in the construction process of the construction of the safety enclosure, the dismantling of the bridge deck anti-collision fence and the dismantling of the bridge deck, the dismantled waste slag is transported outwards along with the dismantling.
The arrangement of the safety protection net not only plays a certain protection role, but also can prevent broken concrete fragments from falling into a river, thereby avoiding damaging the ecological environment; the waste slag is removed along with outward transportation, so that broken slag is prevented from being scattered downwards a bridge, and the waste slag is prevented from being accumulated on the bridge, the burden of the bridge in the removing process is prevented from being increased, and potential safety hazards are avoided.
Further, in the step of releasing the longitudinal and transverse connection, the width of the released wet joint and the width of the diaphragm concrete are 20-40 cm, and the longitudinal bridge deck is continuously disconnected and the beam head is prevented from being extruded by an adjacent beam.
Further, the operation of beam taking, beam falling and beam transporting is carried out by utilizing the bridge girder erection machine in the whole process of the main span full-hanging beam dismantling operation; the bridge girder erection machine is assembled on the track and pushed to the dismantling hole, and the bridge girder erection machine is fixed; the bridge girder erection machine transversely moves the girder to be dismantled to fall down by the transverse truss car, and the girder to be dismantled is bound and hoisted; after a beam body to be dismantled is hoisted, a truss car is transversely moved to the center of a beam span, the truss car is placed at a position 1.5m away from the beam end, and a hoisting point is exposed; longitudinally moving the truss girder to the position above the girder transporting flat car spanned behind the bridge girder erection machine, finally, dropping the girder body to be dismantled on the girder transporting flat car, and fixing the girder body to be dismantled, namely, starting to transport the girder; and after the girder body to be dismantled is transported to a fixed place, the longitudinal-moving truss vehicle moves back to the rear end, the front support and the pier top connecting bolt are dismantled, the front support is hung on the nose frame, the bridge girder erection machine is moved backwards, and the steps are repeated to dismantle and install the next span girder.
Furthermore, the front and rear vehicle actions of the bridge girder erection machine are kept consistent and synchronous when the bridge girder is conveyed, the speed is 5m/min, and the bridge girder erection machine is monitored by a specially-assigned person to prevent the support of the girder from loosening; the gravity center of the beam body to be dismantled is required to be located on the longitudinal central line of the beam transporting flat car, and the deviation is not more than 20 mm.
Furthermore, the semi-hanging beam and the T beam are hoisted by the crane during dismantling, and the crane is stopped below the bottom side of the upper beam on the bridge bottom open ground during dismantling and is arranged according to the range required by the crane operation; after the longitudinal and transverse connection of the beam body to be dismantled is removed, retaining part of transverse clapboard reinforcing steel bars, binding the beam body to be dismantled by using a steel wire rope of a crane, removing all connecting reinforcing steel bars, hoisting by using the crane, slowly moving the beam body to be dismantled to the upper part of the open space, rotating the beam body to be dismantled by using cables at two ends of the beam end by 28-30 degrees, and slowly lowering the beam body to be dismantled to the open space of the bridge bottom after the capping beams at two ends are not influenced and enough safety distance is ensured. Can ensure that the pier stud and the capping beam are not damaged.
Furthermore, after the main span full-hanging beam dismantling operation is completed, the half-hanging beam and the T beam dismantling operation are carried out, the deformation condition of the T-shaped box girder between the girder bodies is observed at any time in the construction period from the completion of the main span full-hanging beam dismantling operation to the execution of the half-hanging beam and the T beam dismantling operation, two deformation observation points are respectively arranged at two ends of the top of the T-shaped box girder, and the deformation condition in the dismantling process is observed in time by using field favorable conditions.
The bracket part of the T-shaped box girder is close to the hanging girder to be dismantled, and important attention must be paid during the dismantling. The vibration of the mechanical chiseling during chiseling and dehumidifying the joint and the beam head basically cannot influence the bracket through the buffering of the rubber support, but the mechanical operation is strictly controlled, so that the bracket structure is prevented from being accidentally injured due to misoperation.
The periphery of the cap beam is prevented from being constructed by using a hydraulic gun machine to do large-motion construction, manual construction or pneumatic pick construction is adopted when necessary, and the cap beam is protected by using a wood board or a sand bag to prevent the cap beam from being damaged by a concrete block; and after the cap beam is dismantled, the concrete slag blocks on the cap beam are cleaned in time.
Furthermore, the half hanging beam and the T beam are disassembled by adopting a method of hanging the beam bottom by penetrating and binding, and a transverse inhaul cable is arranged to keep and increase the transverse stability of the beam body; when the bridge body is dismantled by the bridge girder erection machine, the weight of the bridge girder erection machine is required to fall on the beam ribs when the bridge girder erection machine runs on a bridge, the main girder is subjected to load checking according to the model of the bridge girder erection machine, and construction can be carried out after the checking is passed.
Compared with the prior art, the invention has the beneficial effects that: 1. the demolition construction method of the bridge superstructure can demolish the main span full-hanging beam, the semi-hanging beam and the T beam of the bridge reasonably and quickly, has good safety, and does not interrupt all traffic of the line where the bridge is located; in consideration of actual conditions such as half-width traffic, simultaneous construction of multiple parts and the like, the operation is carried out in a mechanical dismantling mode, so that the influence on the surrounding environment can be reduced as much as possible; 2. the demolition method adopted by the construction method is basically contrary to the installation flow of the bridge, and is convenient to master and implement; under the conditions of limited construction boundary, incomplete mechanical equipment and unavailable construction conditions, the construction method is adopted to solve the problem of overall beam body dismantling, has small influence on operation, ensures construction safety and has certain popularization significance; 3. the bridge is dismantled according to the steps of the construction method, and the general principle that the bridge is safe, first, orderly constructed, balanced and symmetrical, first, second, and third, and the whole is broken up can be carried on, so that the bridge is guaranteed to be dismantled safely and quickly; 4. the construction method can reserve and continue to use the reasonably controlled demolition part, the T-shaped box girder, the pier capping beam and the like; the main span full-hanging beam, the half-hanging beam and the T beam which are dismantled are stored in a classified mode and are treated in a centralized mode according to the use condition, and stacked waste residues are all conveyed to a waste residue disposal site which meets the requirements of local environmental protection departments, so that the dispersion and pollution of construction waste are reduced.
Drawings
FIG. 1 is a (right panel) schematic illustration of a demolition procedure for a bridge superstructure of the present invention;
FIG. 2 is a (left panel) schematic illustration of a demolition procedure for a bridge superstructure of the present invention;
FIG. 3 is a flow chart of a demolition process of a demolition construction method of a bridge superstructure according to the present invention;
FIG. 4 is a first schematic lifting diagram of the demolition construction method of the superstructure of a bridge according to the present invention;
fig. 5 is a second schematic lifting diagram of the demolition construction method of the bridge superstructure of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The first embodiment is as follows:
in order to facilitate understanding and description of the technical scheme of the invention, a certain bridge section is taken as an example for description, the total length of the bridge is 417m, the upper structure of the main bridge adopts a prestressed concrete T-shaped rigid frame box girder bridge with a hanging beam of 80m, a common concrete cast-in-place T beam of 16m and a prefabricated prestressed T beam of 25m, and the total number of holes is 15; the demolition work is carried out in two stages: in the first stage, a right (single) bridge deck and 28T beams (including a main span 25m full-hanging beam, a semi-hanging beam and a common 25m prestressed T beam) are dismantled; and in the second stage, the left deck (single deck) and the 28T-shaped beams are removed, and the removal schematic diagram is shown in figures 1 and 2.
The T-shaped beam to be dismantled is only 4#、5#、6#、7#、8#、9#、10#The span is seven spans (the shaded part shown in fig. 1 and fig. 2), and three areas are divided for dismantling according to the actual situation of the site.
Firstly, the number region is a main span 25m full-hanging beam, 4 beams are totally arranged, an upper span water channel is arranged, after the anti-collision wall is removed, a bridge erecting machine is adopted to reversely operate according to the sequence of beam erecting, firstly, the transverse connection among the 4 beams is gradually released, and then the bridge erecting machine is used for hanging the beam pieces to 6#And (4) carrying the beam to a No. two area (4-6 bridge deck) by using a beam transporting flat car on the T structure, hoisting the beam to the ground together with the beam piece with the three spans, and finally crushing the beam by using a hydraulic crusher and then transporting the crushed beam to a slag disposal site.
And the No. II area is a semi-mounted beam and a common 25m prestressed T beam which are 12 beams in total, and the bridge bottom of the area is land. And combining the field favorable conditions, and directly hoisting the T-shaped beam to the bottom of the bridge by using a large-tonnage crane to crush and remove the T-shaped beam. After the anti-collision wall is removed, 2 100T cranes are arranged at the proper position of the bridge bottom, after the transverse connection between the beam pieces is gradually removed, the T beam is directly hung to the empty ground at the bridge bottom and then crushed by a hydraulic crusher, and the loader is loaded outside the vehicle and transported to a slag disposal site. When the semi-mounted beam is dismounted, the semi-mounted beam is firstly started to be pressed according to 6#—5#—4#And dismantling the spans one by one according to the sequence of the spans.
The third area is the same as the second area, and the dismantling sequence is 8#—9#—10#The span is performed span by span.
The scheme makes full use of on-site favorable conditions, reduces the situation of high-altitude operation to the maximum extent, and the beam pieces are directly hoisted to the ground for operation after the transverse connection is removed, thereby fully ensuring the construction safety, the bridge structure safety and the traffic safety of adjacent half bridge decks.
As shown in fig. 3, the specific process flow and process of dismantling mainly include several steps of dismantling preparation, construction safety enclosure, dismantling of bridge deck crash barriers, bridge deck dismantling, beam slab dismantling and site cleaning, and the key points and difficulties are focused on the dismantling operation of a main span 25m full-hanging beam and a half-hanging beam and a common 25m prestressed T-beam.
(1) Dismantling a full hanging beam with a main span of 25 m: the method comprises five steps of removing longitudinal and transverse connection, positioning a bridge girder erection machine, taking a beam, feeding the beam and transporting the beam, wherein the dismantling sequence is as follows: the outer beams are firstly disassembled, and then the outer beams are disassembled piece by piece from outside to inside.
Step one, removing the vertical and horizontal relations:
and chiseling bridge deck continuous and wet joints and diaphragm concrete between beam bodies by using a small hydraulic gun, and cutting off the reinforcing steel bars by using gas cutting. The width of the removed wet joint and the transverse clapboard is 20-40 cm. The longitudinal deck is continuously broken and the beam heads are guaranteed against being squeezed by adjacent beams.
Secondly, positioning a bridge girder erection machine:
and pushing the bridge erecting machine assembled on the track to the dismantling hole, and fixing the bridge erecting machine.
Thirdly, taking a beam:
and the transverse truss vehicle transversely moves the bridge girder erection machine to fall down to the position of the girder to be dismantled, and binds and lifts the girder to be dismantled. The bundle beam can use a steel wire rope or a special lifting appliance, and the lifting appliance is designed according to the structural form and the weight parameters of the beam. The suspension point setting position is allowed by design, and the position range of the beam transporting vehicle fulcrum is considered.
After the detached beam body is lifted to a certain height, the truss vehicle is transversely moved to the center of the beam span, the truss vehicle is placed at a position 1.5m away from the beam end, and a lifting point is exposed. The beam body is conveyed by a special person, the front and rear vehicles have consistent actions at a speed of 5m/min, and are kept synchronous and monitored by the special person to prevent the beam body from bearing looseness.
Fourthly, beam falling:
and longitudinally moving the truss girder to the position above the girder transporting flat car spanned behind the bridge girder erection machine, finally, dropping the girder body to be dismantled on the girder transporting flat car, and fixing the girder body to be dismantled, thus starting to transport the girder. The gravity center of the beam body should be located on the longitudinal central line of the beam transporting flat car, and the deviation should not exceed 20 mm.
Fifthly, beam conveying:
after the beam falling operation is carried out in place, the beam bodies to be dismantled are transported to a fixed place by a beam transporting flat car to be stacked and processed uniformly. And the longitudinal moving truss vehicle moves back to the rear end, the connecting bolt of the front support and the pier top is removed, the front support is hung on the nose frame, and the bridge girder erection machine moves backwards. And repeating the steps to remove and install the next span beam.
(2) Dismantling a half-hanging beam and a common 25m prestressed T beam:
dismantling a half hanging beam and a common 25m prestressed T beam (a No. two area and a No. three area), directly hoisting and moving to the ground at the bottom of a bridge by adopting a 100T truck crane, and then crushing and clearing; the dismantling sequence is also as follows: the outer beams are firstly disassembled, and then the outer beams are disassembled piece by piece from outside to inside.
Similarly, the first step is to release the longitudinal and transverse connection; and secondly, arranging a crane, wherein the crane is stopped below the bottom side of the upper beam on the bridge bottom open ground and is arranged according to the range required by the operation of the crane.
Thirdly, fourthly, taking and falling the beam: after the longitudinal and transverse connection of the beam body to be dismantled is removed, retaining part of transverse clapboard reinforcing steel bars, binding the beam body to be dismantled by using a steel wire rope for a crane, removing all connecting reinforcing steel bars, hoisting by using the crane, slowly moving the beam body to be dismantled to the upper part of the open ground, rotating the beam body to be dismantled by 30 degrees by using cables at two ends of the beam end (see figure 4 or figure 5), and slowly lowering the beam body to be dismantled to the open ground at the bottom of the bridge after the capping beams at two ends are not influenced and a sufficient safety distance is ensured; this operation ensures that the piers and capping beams are not damaged.
As the crane is adopted for operation, beam taking, beam falling and beam transporting can be completed by the crane, the half-hanging beam and the common 25m prestressed T beam which are dismantled step by step are transported to the ground below the bridge, and are intensively crushed by a 200-type hydraulic gun machine and transported by a dump truck to a slag disposal site meeting the requirements of local environmental protection departments.
The method comprises the protection measures for the T-structure box beam, the pier stud, the bent cap and the hat beam in the dismantling process of the main span 25m full-hanging beam, the half-hanging beam and the common 25m prestressed T beam, and fully guarantees the structural safety of the part which is not dismantled.
Example two:
the embodiment provides a method for dismantling hoisting safety calculation in the first embodiment.
(1) Demolition beam weight calculation
The quantity of concrete in one girder is shown in Table 1, and the most unfavorable center girder (difficult) is taken as the self weight Q1＝50.02t。
Table 1: concrete quantity meter of a slice girder
The average thickness of the bridge deck pavement is 13cm, and the self weight Q is calculated2＝0.13×25×2.3×2.5＝18.7t。
The amount of prestressed steel strand material for a T-beam is shown in Table 2, the total weight Q of the prestressed steel strand3＝0.57t。
Table 2: prestressed steel strand material quantity table of a slice T roof beam
Therefore, the hoisting weight Q of the middle beam is Q1+ Q2+ Q3 is 50.02+19.07+0.57 is 69.66t, and the whole is 70 t.
(2) Hoisting machinery and hanger model selection
According to the calculation result, the engineering characteristics and the site terrain conditions, and in combination with other factors to be considered, 1 JQIII 100-30 type bridge girder erection machine and 2 QY100H type automobile cranes are preliminarily selected to carry out the operation of dismantling and hoisting to the ground.
(3) Hoist wire rope security calculation
The lifting capacity of 2 QY100H type automobile cranes (cranes) is 100t, the beam body is lifted at the current time according to the calculation of 70t of the heaviest 25mT beam, and the two ends are lifted. The hoisting position is arranged at a position 1m away from the beam end, and two 100-ton cranes are adopted to respectively hoist from two ends. The tension P of the hoisting rope is:
p70 t/2/2 t 17.5t, and the tensile force of each side of the steel wire rope is 171.5 KN.
Therefore, a phi 39-6 multiplied by 37 steel wire rope can be selected, the tensile strength is 1814MPa, and the breaking tension is 1020 kN. The safety factor is 1020/171.5-5.95, and the requirement is met. Each length L of the hoisting steel wire rope is 7 m. The positions and the ranges of the two cranes are shown in figures 4 and 5.
(4) Anti-overturning computing
The unfavorable working condition I when the truck crane works is that 3 points touch the ground, namely 3 supporting legs support the weight (including self weight and load) of the whole crane; the unfavorable condition II is a 2-point landing, i.e. 2 legs support the weight (including self-weight and load) of the whole crane, and the truck crane is in a critical overturning state. Under any working condition, the foundation must be ensured to sufficiently support the support legs of the truck crane so as to prevent the support legs from sinking and the truck crane from being unstable to overturn.
The safety factor of the bearing capacity of the foundation is taken to be 1.2, and the pressure of the truck crane to the ground is as follows:
in the formula: g, the self weight of the truck crane, and taking the checking calculation of a 100t crane as 66 t;
q1-the weight of the hung 25mT beam is 70.0t, and the bearing weight of a single crane is 35 t;
q2-weight of the steel cord used, 0.1 t;
n is the number of legs;
s-area of footprint of single leg
General road bed bearing capacity value is taken as the bearing capacity value that foundation soil needs to satisfy, and through foundation treatment (road roller rolling etc.) in this scheme, foundation bearing capacity value must be satisfied and not less than 270 KPa.
Working condition I: 3, the pressure of the truck crane to the foundation is satisfied:
to obtain: s>1.3m2
Therefore, the landing area S is not less than 1.3m when the single leg of the truck crane is in a landing position2And meanwhile, the bearing capacity of the foundation is not less than 270KPa, so that the requirement can be met.
Working condition II: 2, the pressure of the truck crane to the foundation is satisfied:
to obtain: s>1.9m2
Therefore, the landing area S is not less than 1.9m when the single leg of the truck crane is in a landing position2And meanwhile, the bearing capacity of the foundation is not less than 270KPa, so that the requirement can be met.
And taking the working condition II as a control design according to a calculation result. When the landing area S of a single support leg of the truck crane is not less than 1.9m2And meanwhile, the bearing capacity of the foundation is not less than 270KPa, so that the requirement can be met.
In order to ensure that the bearing capacity of the foundation can meet the requirement, a simulation test is carried out on the corresponding ground before hoisting construction, if the test result does not meet the requirement of the bearing capacity, the foundation of the parking position needs to be preprocessed, and the hoisting construction can be carried out after the requirement is met.
In the dismantling preparation stage, after the possible conditions and the data to be determined are calculated, on one hand, the construction safety can be ensured, on the other hand, reasonable arrangement modes of hoisting machinery, a hoisting tool and the like can be obtained, repeated adjustment in the construction process is avoided, and the construction efficiency can be improved; and the weight calculation of the beam body to be dismantled, the type selection of the hoisting machinery and the hoisting tool, the safety calculation of the hoisting steel wire rope and the anti-overturning calculation are simple and reasonable, and the requirements of safe construction specifications are met.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. A demolition construction method of a bridge superstructure is characterized by mainly comprising the steps of demolition preparation, construction safety containment, demolition of a bridge deck anti-collision fence, demolition of a bridge deck, demolition of a beam slab and site cleaning; the beam plate dismantling comprises main span full-hanging beam dismantling operation and half-hanging beam and T beam dismantling operation; the main span full-hanging beam dismantling operation and the half-hanging beam and T beam dismantling operation comprise the following steps:
(1) and (3) removing the vertical and horizontal relation: removing continuous and wet joints and diaphragm concrete of the bridge deck between the beam bodies by using a gun chisel, and cutting off the reinforcing steel bars by using gas cutting;
(2) taking a beam: a bridge girder erection machine or a crane is adopted, and a steel wire rope or a lifting appliance is matched to bundle a girder and lift the girder body to be dismantled;
(3) beam falling and beam conveying: for the main span full-hanging beam, the main span full-hanging beam falls on a beam transporting flat car and is transported to a fixed place to be stacked and uniformly processed; and for the half-hanging beam and the T beam, the moved beam bodies fall on the air and land step by step, crushing is intensively carried out by adopting a cannon, and finally, clearing is carried to a specified place.
2. The demolition construction method of a bridge superstructure according to claim 1, wherein the demolition preparation includes a process of determining a demolition overall principle and formulating a demolition overall scheme, division and numbering of construction areas are performed according to the span number of the bridge, the bridge is successively constructed according to two stages, namely a left frame and a right frame, and demolition sequences are: the outer beams are firstly disassembled, and then the outer beams are disassembled piece by piece from outside to inside.
3. A demolition construction method of a bridge superstructure according to claim 1, characterized in that in the demolition preparation step, disassembly and assembly hoisting safety calculation is also needed, mainly comprising demolition beam weight calculation, hoisting machinery and hanger type selection, hoisting wire rope safety calculation and anti-overturning calculation, and simulation test is performed on the corresponding ground before hoisting construction.
4. The method of demolition construction of a bridge superstructure according to claim 1, wherein said constructing safety containment comprises arranging safety screens at both sides of the bridge, and demolished spoil is shipped along with demolition during the construction of said constructing safety containment, said deck crash barrier demolition and said deck demolition.
5. The demolition construction method of a bridge superstructure according to claim 1, wherein in the step of releasing the longitudinal and lateral relations, the width of the wet joint and the diaphragm concrete released is 20-40 cm, the longitudinal bridge deck is continuously broken and the beam head is guaranteed not to be pressed by the adjacent beam.
6. The demolition construction method of a bridge superstructure according to claim 1, wherein the main span full-hanging beam demolition work is performed with the bridge girder erection machine for beam taking, beam dropping and beam transporting operations throughout; the bridge girder erection machine is assembled on the track and pushed to the dismantling hole, and the bridge girder erection machine is fixed; the bridge girder erection machine transversely moves the girder to be dismantled to fall down by the transverse truss car, and the girder to be dismantled is bound and hoisted; after a beam body to be dismantled is hoisted, a truss car is transversely moved to the center of a beam span, the truss car is placed at a position 1.5m away from the beam end, and a hoisting point is exposed; longitudinally moving the truss girder to the position above the girder transporting flat car spanned behind the bridge girder erection machine, finally, dropping the girder body to be dismantled on the girder transporting flat car, and fixing the girder body to be dismantled, namely, starting to transport the girder; and after the girder body to be dismantled is transported to a fixed place, the longitudinal-moving truss vehicle moves back to the rear end, the front support and the pier top connecting bolt are dismantled, the front support is hung on the nose frame, the bridge girder erection machine is moved backwards, and the steps are repeated to dismantle and install the next span girder.
7. The demolition construction method of a bridge superstructure according to claim 6, wherein the front and rear vehicle motions of the bridge girder erection machine are kept consistent and synchronous while transporting the girder body, and the speed is 5 m/min; the gravity center of the beam body to be dismantled is required to be located on the longitudinal central line of the beam transporting flat car, and the deviation is not more than 20 mm.
8. The demolition construction method of a bridge superstructure according to claim 1, wherein the half-hanging beam and T-beam demolition work is hoisted by the crane, and during demolition, the crane is stopped under the bottom side of the upper beam in the open ground of the bridge bottom and is arranged in a range required by the crane work; after the longitudinal and transverse connection of the beam body to be dismantled is removed, retaining part of transverse clapboard reinforcing steel bars, binding the beam body to be dismantled by using a steel wire rope of a crane, removing all connecting reinforcing steel bars, hoisting by using the crane, slowly moving the beam body to be dismantled to the upper part of the open space, rotating the beam body to be dismantled by using cables at two ends of the beam end by 28-30 degrees, and slowly lowering the beam body to be dismantled to the open space of the bridge bottom after the capping beams at two ends are not influenced and enough safety distance is ensured.
9. The demolition construction method of a bridge superstructure according to claim 1, wherein the half-hanging beam and T-beam demolition work is performed after the main-span full-hanging beam demolition work is completed, and during a construction period from the completion of the main-span full-hanging beam demolition work to the performance of the half-hanging beam and T-beam demolition work, a deformation condition of a T-box beam between beam bodies is observed at any time, and a deformation observation point is provided at each of both ends of a top of the T-box beam.
10. A dismantling construction method for a bridge superstructure according to claim 1, wherein the half hanging beam and the T beam adopt a hoisting method of penetrating and binding the beam bottom, and a transverse stay cable is arranged; when the bridge body is dismantled by the bridge girder erection machine, the weight of the bridge girder erection machine is required to fall on the beam ribs when the bridge girder erection machine runs on a bridge, the main girder is subjected to load checking according to the model of the bridge girder erection machine, and construction can be carried out after the checking is passed.
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