CN108750915B - Prefabricated box girder top plate reinforcing steel mesh lifting appliance and operation method - Google Patents
Prefabricated box girder top plate reinforcing steel mesh lifting appliance and operation method Download PDFInfo
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- CN108750915B CN108750915B CN201810791644.5A CN201810791644A CN108750915B CN 108750915 B CN108750915 B CN 108750915B CN 201810791644 A CN201810791644 A CN 201810791644A CN 108750915 B CN108750915 B CN 108750915B
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- 229910001294 Reinforcing steel Inorganic materials 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims abstract description 36
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 94
- 239000010959 steel Substances 0.000 claims abstract description 94
- 238000004364 calculation method Methods 0.000 claims abstract description 7
- 238000012360 testing method Methods 0.000 claims abstract description 7
- 238000012795 verification Methods 0.000 claims abstract description 6
- 230000003014 reinforcing effect Effects 0.000 claims description 78
- 230000002787 reinforcement Effects 0.000 claims description 38
- 230000009471 action Effects 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 9
- 238000004088 simulation Methods 0.000 claims description 8
- 238000013461 design Methods 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 238000002474 experimental method Methods 0.000 claims description 5
- 239000004568 cement Substances 0.000 claims description 4
- 238000012545 processing Methods 0.000 claims description 4
- 239000000725 suspension Substances 0.000 claims description 4
- 238000005452 bending Methods 0.000 claims description 3
- 238000004904 shortening Methods 0.000 claims description 2
- 238000010276 construction Methods 0.000 abstract description 6
- 230000008901 benefit Effects 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 2
- 238000004134 energy conservation Methods 0.000 abstract description 2
- 230000009467 reduction Effects 0.000 abstract description 2
- 230000007547 defect Effects 0.000 description 2
- 238000009417 prefabrication Methods 0.000 description 2
- 102100035115 Testin Human genes 0.000 description 1
- 101710070533 Testin Proteins 0.000 description 1
- 238000011161 development Methods 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C1/00—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles
- B66C1/10—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith for transmitting lifting forces to articles or groups of articles by mechanical means
- B66C1/12—Slings comprising chains, wires, ropes, or bands; Nets
- B66C1/125—Chain-type slings
Abstract
The invention discloses a prefabricated box girder roof reinforcing steel bar net sheet lifting appliance and an operation method, which belong to the field of bridge construction, wherein the lifting appliance mainly comprises a lifting frame, two travelling crane lifting points, a plurality of pairs of lifting chains and the like, and the operation method is characterized in that: 1. the hanger with high rigidity is adopted to hoist the steel bar net sheet, so that the degree of mechanization is high, the labor intensity is reduced, and the working efficiency is improved; 2. adopting a theoretical calculation and actual test verification method to calculate the maximum deviation of wavy dislocation generated on the horizontal plane due to the influence of accidental vibration or wind power when lifting the reinforcing steel mesh; 3. the length of the hanging chain is adjusted through the buckle, so that the plane error of dislocation deformation of the reinforcing steel bar net sheet is reduced or avoided, and the quality of the prefabricated box girder is improved. Therefore, the prefabricated box girder top plate reinforcing steel mesh lifting appliance has the advantages of convenience in adjusting the lifting error of the reinforcing steel mesh, reliable quality, high degree of mechanization and the like, can improve the quality of the prefabricated box girder by combining with a corresponding operation method, and has the effects of energy conservation and emission reduction, and obvious economic and social benefits.
Description
Technical Field
The invention relates to the field of bridge construction, in particular to a prefabricated box girder top plate reinforcing steel mesh lifting appliance and an operation method.
Background
The assembled bridge is a development trend of current bridge construction, and requires high-precision intelligent reinforcement processing, factory component prefabrication and standardized program installation. In the construction process of the assembled bridge, bridge deck beam slab prefabrication is a key link, wherein the modular steel reinforcement framework manufacture and the programmed hoisting play an important role in the quality and the precision of the prefabricated bridge deck slab.
And after the box girder body steel bar framework is hoisted into the outer formwork, a core mould is placed in the box girder body steel bar framework, then the top plate steel bar mesh is hoisted, the box girder body steel bar framework and the top plate steel bar mesh are fastened and fixed, and cement concrete is poured. Because the roof reinforcing bar net piece is the thin planar structure that is formed by longitudinal reinforcement and horizontal reinforcing bar ligature, to the beam slab of large span, roof reinforcing bar net piece length-width ratio is big, rigidity is little, receives the influence of accidental vibration or wind-force in the handling process, very easily produces wave dislocation deformation at the horizontal plane, places the difficult planar position of adjusting roof reinforcing bar net piece dislocation deformation on box girder body steel reinforcement skeleton, causes the quality defect of prefabricated box girder, influences the construction precision and the bridging quality of assembled bridge girder.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide the prefabricated box girder roof reinforcing steel mesh lifting tool with convenient adjustment of the lifting error of the reinforcing steel mesh, reliable quality and high mechanization degree and the operation method.
The technical problems of the invention are realized by the following technical scheme:
the steel mesh lifting appliance for the top plate of the prefabricated box girder comprises a steel frame girder lifting frame with a triangular cross section, wherein two travelling crane lifting points are arranged at the top of the lifting frame, a plurality of pairs of lifting chains which are uniformly distributed at equal intervals along the longitudinal direction of the lifting frame are arranged at the bottom of the lifting frame, each pair of lifting chains consists of two lifting chains which are transversely and symmetrically arranged at two sides of the lifting frame, and the top end of each lifting chain is buckled with a buckle fixed at the bottom of the lifting frame, and the bottom end of each lifting chain is buckled and connected with a steel mesh through the buckle; the hanging frame is lifted by the travelling crane to move, and then the steel bar meshes are driven by a plurality of pairs of hanging chains to be conveyed to the prefabricated box girder in the prefabricated box girder template.
The steel bar net sheet is of a thin plane structure formed by binding a plurality of longitudinal steel bars and a plurality of transverse steel bars, and a plurality of hanging chain hanging points which correspond to the hanging chain bottom buckles and are in buckling connection are arranged on the steel bar net sheet.
The effective length of the reinforcing mesh isBy->Root longitudinal bar and->The transverse steel bars are bound and suspended by a hanger>For all lengths +.>The hanging chains of the (2) are used for hoisting the reinforcing steel bar net sheet, and the distance between the adjacent hanging chains is +.>The method comprises the steps of carrying out a first treatment on the surface of the The rigidity of the reinforcing mesh is mainly composed of +.>Root longitudinal bar and->The transverse steel bars are formed, and for a prefabricated box girder top plate with a large span, the steel bar net piece has large length-width ratio and small rigidity, and the horizontal wave shape dislocation is easy to generate in the lifting processShape, therefore, the following assumptions are made:
the length of the chord is the length between the first hanging chain and the last hanging chain, namely the effective length between the starting point and the end pointThe linear density of the chords is +.>The method comprises the steps of carrying out a first treatment on the surface of the The string is deformed without resisting bending moment, elongation and tension +.>Meets the Huk theorem;
secondly, when lifting reinforcing mesh, a first hanging chain starting point 1 and a last hanging chain ending pointBetween (I)>The vibration or wind force is generated in the horizontal plane>Axis deviation->Distance as initial condition, deviation +.>Effective length of the steel mesh sheet in the longitudinal direction>The weight of the reinforcing mesh is not counted because the weight is tiny;
thirdly, the reinforcing mesh performs micro vibration in the horizontal plane, the vibration direction of each point is perpendicular to the balance position, and a function is usedIndicating the arbitrary moment of the reinforcing mesh sheet>Is +.>；
According to the assumption, the micro vibration differential equation of the reinforcing mesh and the vibration tension of the reinforcing meshAnd solution of differential equation->Calculated from the following formula:
equation one,
Formula II,
The first hanging chain starting point 1 and the last hanging chain ending point when the reinforcing steel bar net sheet is liftedBetween (I)>The vibration or wind force is generated in the horizontal plane, namely +.>Axis deviation->Distance as initial condition, tension +.>Mean value of>From the Huke theorem
Formula III,
A difference method or computer aided calculation can be adopted to obtain a numerical solution;
each symbol in the first, second and third formulas is defined as:
the longitudinal effective length of the reinforcing mesh sheet, namely the length between the first hanging chain and the last hanging chain,/for the reinforcing mesh sheet>；
-length between longitudinal edge of reinforcement mesh and head or end sling,/->；
-hanging under a hanger for lifting reinforcing mesh>Root lengthI.e. numbered +.>All are->A length of hanging chains, the spacing between adjacent hanging chains,/->，/>；
-the first lifting chain starting point 1 and the action of vibration or wind force when lifting the reinforcement mesh>Length between->；
-end point of last hanging chain when lifting reinforcing mesh>Is effective against vibration or wind force>Length between->；
-hanging at the bottom of the hanger->For each of the hoist lengths, < >>；
-pairs of hanging chains suspended at the bottom of the hanger;
-the first lifting chain starting point 1 and the action of vibration or wind force when lifting the reinforcement mesh>The length between, determined by simulation or experiment, < >>；
-the first hanging chain starting point 1 and the first hanging chain ending point +.>Between (I)>The vibration or wind force is generated in the horizontal plane, namely +.>Distance of axis offset>As determined by simulation or experimentFix (I) the>；
-reinforcement mesh simulation chord at any moment +.>Is +.>Is>，/>；
-coefficient of->；
-average tension produced by micro-vibrations in the longitudinal effective length of the reinforcement mesh, +.>；
-the first lifting chain starting point 1 and the action of vibration or wind force when lifting the reinforcement mesh>Tension caused by micro-vibration between +.>；
-end point of last hanging chain when lifting reinforcing mesh>Is effective against vibration or wind force>Tension produced,/->；
-density of reinforcement mesh per meter in longitudinal direction, < >>；
-longitudinal tensile stiffness of the section of the reinforcement mesh, wherein +.>For the longitudinal tensile modulus of elasticity of the section, < >>Is the transverse cross section of the reinforcing mesh sheet>；
When the steel bar net piece is placed on the box girder steel bar framework in the prefabricated box girder template, the horizontal plane generates wavy dislocation and the abscissa is +.>Is used for the control of the maximum deviation value of (c),；
the steel bar net sheet is placed on the steel bar framework of the box girder body in the prefabricated box girder template to tolerate the dislocation error value,。
the steel frame beam hanging frame comprises channel steel longitudinal beams arranged at three corner points of the triangular steel frame beam and a plurality of groups of round steel web members surrounding the channel steel longitudinal beams at the three corner points, wherein the plurality of groups of round steel web members are distributed at equal intervals along the channel steel longitudinal beams, and the plurality of groups of round steel web members and the channel steel longitudinal beams at the three corner points are welded firmly.
The hanging chain is a multi-section hanging chain formed by sequentially connecting ring-by-ring oval steel rings, and the buckles are respectively arranged on the bottom of the hanging bracket and the oval steel ring at the bottommost end of the multi-section hanging chain.
The buckle is a buckling structure capable of being opened and self-locked.
An operation method of a prefabricated box girder top plate reinforcing steel mesh lifting appliance comprises the following steps:
step one, designing and manufacturing prefabricated box girder top plate reinforcing steel mesh lifting appliance
(1) Manufacturing a prefabricated box girder top plate reinforcing steel mesh hanger according to a box girder top plate reinforcing steel mesh design drawing;
(2) through formula I and formula IIBottom suspension of two-and formula three-trial-calculation hanging bracketLength of hanging chain->Different initial conditions->String vibration function with reinforcing mesh>Maximum amplitude, and selecting the wave-shaped dislocation tolerance error of the reinforcing mesh sheet meeting the standard specification requirement>Chain length of +.>；
(3) Verification of the pendant chain length by field testIn the process, the maximum deviation of the wavy dislocation of the reinforcing mesh sheet is +.>Meets the standard specification requirements; if the requirements are not met, adjusting a plurality of pairs of buckles at the bottom of the hanging frame, which are connected with the next section or the next sections of the multi-section hanging chain of the plurality of pairs of hanging chains, shortening the length of the hanging chain, and performing test verification again until the requirements are met;
step two, binding reinforcing steel meshes of prefabricated box girder top plate
(1) Processing longitudinal steel bars and transverse steel bars of the steel bar meshes by intelligent steel bars, and binding and forming on a die carrier;
(2) checking the number and the spacing of longitudinal steel bars and transverse steel bars of the steel bar meshes, and binding the firmness degree to meet the design requirement;
step three, hoisting the reinforcing mesh into place and pouring box girder concrete
(1) Moving the travelling crane and the hanging frame to the upper part of the binding mould frame of the reinforcing steel bar net sheet, and correspondingly buckling the hanging chain hanging points of the reinforcing steel bar net sheet by the buckles at the bottom ends of the hanging chains;
(2) the travelling crane is operated to move the reinforcing mesh to be conveyed to a reinforcing framework of a box girder body in the prefabricated box girder template, and the reinforcing mesh and the reinforcing framework of the box girder body are firmly bound;
(3) pouring box girder cement concrete, and curing to be qualified.
Compared with the prior art, the invention mainly designs a steel mesh lifting appliance for a top plate of a precast box girder and an operation method, wherein the lifting appliance structure mainly comprises a steel frame girder lifting frame with a triangular cross section, two crane lifting points arranged at the top of the lifting frame, a plurality of pairs of lifting chains which are uniformly distributed at equal intervals along the longitudinal direction of the lifting frame and are arranged at the bottom of the lifting frame, and the like, the lifting chains realize the adjustable length of the lifting chains through buckles at the bottom of the lifting frame and the bottom of the lifting chains, so that the lifting frame is lifted and moved by a crane, and the steel mesh is driven by the plurality of pairs of lifting chains to be conveyed into the precast box girder in a precast box girder template, and the operation method mainly has the following characteristics that: 1. the hanger with higher rigidity is adopted, and the steel bar net sheet is lifted by the travelling crane, so that the degree of mechanization is high, the labor intensity is reduced, and the working efficiency is improved; 2. adopting a theoretical calculation and actual test verification method to calculate the maximum deviation of wavy dislocation generated on the horizontal plane due to the influence of accidental vibration or wind power when lifting the reinforcing steel mesh; 3. the length of the hanging chain is adjusted through the buckle arranged at the bottom of the hanging frame, so that the plane error of dislocation deformation of the reinforcing steel mesh is reduced or avoided, and the quality of the prefabricated box girder is improved. Therefore, the prefabricated box girder top plate reinforcing steel bar net piece lifting appliance has the advantages of convenience in adjusting the lifting error of the reinforcing steel bar net piece, reliable quality, high degree of mechanization and the like, can improve the quality of the prefabricated box girder by combining a corresponding operation method, has the effects of energy conservation and emission reduction, and has remarkable economic and social benefits.
Drawings
Fig. 1 is a schematic elevation view of the present invention.
Fig. 2 is a left side view of fig. 1.
Fig. 3 is a top view of a reinforcing mesh.
Fig. 4 is a calculation diagram of the initial condition of the reinforcing mesh.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the drawings.
1-4, 1 part of reinforcing mesh, 11 parts of longitudinal reinforcing steel, 12 parts of transverse reinforcing steel, 2 parts of hanging bracket, 21 parts of channel steel longitudinal beam, 22 parts of round steel web member, 3 parts of driving hanging point, 4 parts of hanging chain, 41 parts of buckle and 42 parts of hanging chain hanging point.
The utility model provides a prefabricated box girder roof reinforcing bar net piece hoist and operation method, as shown in fig. 1-3, belongs to assembled bridge construction field, and wherein prefabricated box girder roof reinforcing bar net piece hoist mainly comprises steel frame girder gallows 2 that the cross-section is triangle-shaped, two driving hoisting points 3 that set up at gallows 2 top, a plurality of pairs of hoist chains 4 that do equidistant evenly distributed along gallows longitudinal direction that set up in gallows 2 bottom.
The steel frame beam hanger 2 is composed of channel steel longitudinal beams 21 arranged at three corner points of a triangle of the steel frame beam and a plurality of groups of round steel web members 22 surrounding the channel steel longitudinal beams at the three corner points, wherein the plurality of groups of round steel web members 22 are uniformly distributed along the channel steel longitudinal beams 21, namely, are distributed at regular intervals, and the plurality of groups of round steel web members 22 are firmly welded with the channel steel longitudinal beams 21 at the three corner points.
The two crane hanging points 3 are used for the crane hanging bracket 2.
The hanging chains 4 are a plurality of pairs of hanging chains 4 which are uniformly distributed at equal intervals along the longitudinal direction of the hanging frame 2, each pair of hanging chains consists of two hanging chains 4 which are transversely and symmetrically arranged at two sides of the hanging frame 2, each hanging chain is a plurality of hanging chains formed by sequentially connecting oval steel rings which are connected with one another in a ring mode, buckles 41 are arranged on the bottom of the hanging frame 2 and the oval steel rings at the bottommost end of the plurality of hanging chains 4, the buckles are of openable and self-locking buckling structures, and then the top end of each hanging chain 4 can be buckled with the buckles 41 fixed at the bottom of the hanging frame 2, and the bottom end of each hanging chain is buckled and connected with the reinforcing steel mesh 1 through the buckles 41; therefore, after the hanging frame 2 is lifted by the crane, the steel bar net sheet 1 can be driven by the hanging chains 4 to be conveyed to the prefabricated box girder in the prefabricated box girder template.
Meanwhile, the reinforcing steel bar net sheet 1 is of a thin plane structure formed by binding a plurality of longitudinal reinforcing steel bars 11 and a plurality of transverse reinforcing steel bars 12, and a plurality of hanging chain hanging points 42 which are in buckling connection with corresponding hanging chain 4 bottom buckles 41 are further arranged on the reinforcing steel bar net sheet 1.
In addition, the effective length of the reinforcing mesh 1 is set asBy->Root longitudinal bars 11 and->The transverse steel bars 12 are bound and are suspended by the hanging frame 2>For all lengths +.>The hanging chains 4 of (2) are used for hoisting the reinforcing mesh, and the distance between the adjacent hanging chains 4 is +.>The method comprises the steps of carrying out a first treatment on the surface of the The rigidity of the reinforcement mesh 1 is mainly composed of +.>Root longitudinal bars 11 and->The transverse steel bars 12 are formed, and for a large-span prefabricated box girder top plate, the steel bar net sheet 1 has large length-width ratio and small rigidity, and is extremely easy to generate horizontal wave shape dislocation deformation in the lifting process, so the following assumption is made:
the reinforcement mesh 1 is regarded as a chord in physics, the length of the chord is the length between the first and last hoist chains, i.e. the effective length between the starting point and the end pointThe linear density of the chords is +.>The method comprises the steps of carrying out a first treatment on the surface of the The string is deformed without resisting bending moment, elongation and tension +.>Meets the Huk theorem;
secondly, when lifting reinforcing mesh 1, a first hanging chain starting point 1 and a last hanging chain ending pointBetween (I)>The vibration or wind force is generated in the horizontal plane>Axis deviation->Distance as initial condition, deviation +.>Effective length of the steel mesh sheet in the longitudinal direction>The weight of the reinforcing mesh is not counted because the weight is tiny;
thirdly, the reinforcing mesh 1 performs tiny vibration in the horizontal plane, the vibration direction of each point is perpendicular to the balance position, and a function is usedIndicating the arbitrary moment of the reinforcing mesh sheet>Is +.>；
According to the assumption, the micro vibration differential equation of the reinforcing mesh 1 and the vibration tension of the reinforcing mesh 1And solution of differential equation->Calculated from the following formula:
equation one,
Formula II,
The first hanging chain starting point 1 and the last hanging chain ending point when the reinforcing steel bar net sheet 1 is liftedBetween (I)>The vibration or wind force is generated in the horizontal plane, namely +.>Axis deviation->Distance as initial condition, tension +.>Mean value of>From the Huke theorem
Formula III,
A difference method or computer aided calculation can be adopted to obtain a numerical solution;
each symbol in the first, second and third formulas is defined as:
the effective longitudinal length of the reinforcing mesh 1, namely the length between the first hanging chain and the last hanging chain, < ->；
-length between longitudinal edge of reinforcement mesh 1 and head or end sling, < >>；
-hanging +.2 under hanger 2 lifting reinforcing mesh 1>The root length is numbered->All are->A length of hoist 4, the spacing between adjacent hoist chains, < >>，/>；
-the first lifting chain starting point 1 and the action of vibration or wind force when lifting the reinforcement mesh 1 +.>Length between->；
-end point of last hanging chain when lifting reinforcing mesh 1 +.>Is effective against vibration or wind force>Length between->；
-hanging at the bottom of the hanger 2->For each sling length of the sling 4, -, is->；
-4 pairs of chains suspended from the bottom of the hanger 2;
-the first lifting chain starting point 1 and the action of vibration or wind force when lifting the reinforcement mesh 1 +.>The length between, determined by simulation or experiment, < >>；
-the first hoist chain start point 1 and the first hoist chain end point +.>Between (I)>The vibration or wind force is generated in the horizontal plane, namely +.>Distance of axis offset>Determined by simulation or experiment, < >>；
-arbitrary moment of simulation chord of the reinforcement mesh 1 +.>Is +.>Is>，/>；
-coefficient of->；
-average tension, +_f, generated by micro-vibrations in the effective longitudinal length of the mesh 1>；
-the first lifting chain starting point 1 and the action of vibration or wind force when lifting the reinforcement mesh 1 +.>Tension caused by micro-vibration between +.>；
-end point of last hanging chain when lifting reinforcing mesh 1 +.>Is effective against vibration or wind force>Tension produced,/->；
-density of reinforcement mesh 1 per meter in longitudinal direction, < >>；
-longitudinal tensile stiffness of the section of the reinforcement mesh 1, wherein +.>For the longitudinal tensile modulus of elasticity of the section, < >>Is the transverse cross section area of the reinforcing mesh 1 +.>；
The reinforcing steel bar net sheet 1 is affected by accidental vibration or wind power to generate vibration in the lifting process, and the box girder is placed in the prefabricated box girder templateWhen the body steel bar framework is arranged, the horizontal plane generates wavy dislocation, and the abscissa is +.>Maximum deviation value of>；
The error value of dislocation is allowed when the reinforcing mesh 1 is placed on the reinforcing framework of the box girder body in the prefabricated box girder template,。
the operation method of the prefabricated box girder top plate reinforcing steel mesh lifting appliance mainly comprises the following steps:
step one, designing and manufacturing prefabricated box girder top plate reinforcing steel mesh lifting appliance
(1) Manufacturing a prefabricated box girder top plate reinforcing steel mesh hanger according to the design drawing of the box girder top plate reinforcing steel mesh 1;
(2) the bottom suspension of the hanger 2 is calculated through the formula I, the formula II and the formula IIILength of the hoist chain 4->Different initial conditions->Vibration function of 1 string of reinforcing mesh>Maximum amplitude, and selecting the wave-shaped dislocation tolerance error ++of the reinforcing mesh 1 meeting the standard specification requirement>Chain length of +.>；
(3) On-site test to verify the length of the hoist chain 4During the process, the maximum deviation of the wavy dislocation of the reinforcing mesh 1 is +.>Meets the standard specification requirements; if the length of the hanging chain is not in accordance with the requirement, a plurality of pairs of buckles 41 at the bottom of the hanging frame are connected with the next section or the next sections of the multi-section hanging chain of the plurality of pairs of hanging chains 4, the length of the hanging chain is shortened, and the test verification is carried out again until the requirement is met;
step two, binding reinforcing steel meshes of prefabricated box girder top plate
(1) The intelligent reinforcement processing reinforcement net 1 comprises a longitudinal reinforcement 11 and a transverse reinforcement 12, and is formed by binding on a die carrier;
(2) checking the number and the spacing of the longitudinal steel bars 11 and the transverse steel bars 12 of the steel bar net sheet 1, and binding the firmness degree to meet the design requirement;
step three, hoisting the reinforcing mesh into place and pouring box girder concrete
(1) Moving the travelling crane and the hanging frame 2 to the upper part of the binding mould frame of the reinforcing mesh 1, and correspondingly buckling and hanging the hanging chain hanging points 42 of the reinforcing mesh 1 by the buckles 41 at the bottom ends of the hanging chains;
(2) the travelling crane is operated to move the reinforcing steel bar net sheet 1 to be conveyed to a reinforcing steel bar framework of a box girder body in the prefabricated box girder template, and the reinforcing steel bar net sheet and the reinforcing steel bar framework of the box girder body are firmly bound;
(3) pouring box girder cement concrete, and curing to be qualified.
The examples of the present invention are only for illustrating the present invention and are not intended to limit the scope of the present invention. It is also to be understood that various changes and modifications may be made by one skilled in the art after reading the teachings of the invention, and such equivalents are intended to fall within the scope of the claims appended hereto.
Claims (6)
1. The utility model provides a prefabricated case roof bar reinforcing bar net piece hoist, includes transversal triangle-shaped's steel frame roof beam gallows (2), its characterized in that gallows (2) top be equipped with two driving hoisting points (3), gallows (2) bottom is equipped with many pairs of hoist chains (4) that do equidistant evenly distributed along gallows longitudinal direction, every pair of hoist chain is by transversely dividing two hoist chains of establishing in gallows (2) both sides symmetrically, the top of every hoist chain (4) with fix buckle (41) lock in gallows (2) bottom, the bottom is connected on reinforcing bar net piece (1) with buckle (41) lock; the hanging frame (2) is lifted by a crane to move, and then the steel bar net sheet (1) is driven by a plurality of pairs of hanging chains (4) to be conveyed to a prefabricated box girder in the prefabricated box girder template; the effective length of the reinforcing mesh (1) isBy->Root longitudinal bar (11)The transverse steel bars (12) are bound and suspended by the hanging frame (2)>For all lengths +.>The hanging chains (4) of the (4) are used for hoisting the reinforcing mesh, and the distance between the adjacent hanging chains (4) is +.>The method comprises the steps of carrying out a first treatment on the surface of the The rigidity of the reinforcing mesh (1) is mainly composed of +.>Root longitudinal bars (11) and->The transverse steel bars (12) are formed, and for a large-span prefabricated box girder top plate, the steel bar net sheet (1) has large length-width ratio and small rigidity, and horizontal wave shape dislocation deformation is very easy to occur in the lifting process, so that the following assumption is made:
the method comprises the steps that a reinforcing mesh (1) is regarded as a chord in physics, and the length of the chord is the length between a first hanging chain and a last hanging chain, namely the effective length between a starting point and an ending pointThe linear density of the chords is +.>The method comprises the steps of carrying out a first treatment on the surface of the The string is deformed without resisting bending moment, elongation and tension +.>Meets the Huk theorem;
when the reinforcing steel mesh (1) is lifted, the starting point of the first hanging chain and the ending point of the last hanging chain are used for liftingBetween (I)>The vibration or wind force is generated in the horizontal plane>Axis deviation->Distance as initial condition, deviation +.>Effective length of the steel mesh sheet in the longitudinal direction>The ratio is tiny, so the steel bar net is not countedThe dead weight of the sheet;
thirdly, the reinforcing mesh (1) performs tiny vibration in the horizontal plane, the vibration direction of each point is vertical to the balance position, and a function is usedIndicating the arbitrary moment of the reinforcing mesh sheet>Is +.>；
According to the assumption, the micro vibration differential equation of the reinforcing mesh (1) and the vibration tension of the reinforcing mesh (1)And solution of differential equation->Calculated from the following formula:
equation one,
Formula II,
The starting point of the first hanging chain and the ending point of the last hanging chain when the reinforcing steel bar net sheet (1) is liftedBetween (I)>The vibration or wind force is generated in the horizontal plane, namely +.>Axis deviation->Distance as initial condition, tension +.>Mean value of>From the Huke theorem, get +.>
Formula III,
A difference method or computer aided calculation can be adopted to obtain a numerical solution;
each symbol in the first, second and third formulas is defined as:
the effective longitudinal length of the reinforcing mesh (1) is the length between the first hanging chain and the last hanging chain, and the reinforcing mesh is->；
-length between longitudinal edge of reinforcement mesh (1) and head or end sling, < >>；
-hanging under a hanger (2) for lifting the reinforcement mesh (1)>The root length is numbered->Are allA length of hoist chain (4), the spacing between adjacent hoist chains, < >>，/>；
-the starting point of the first hoist chain and the action of vibration or wind force when hoisting the reinforcement mesh (1)>Length between->；
-end point of last hanging chain when lifting reinforcing mesh (1)>Is effective against vibration or wind force>Length between->；
-hanging the bottom of the hanger (2)>For each of the hoist chains (4) length, < > of the hoist chain>；
-the logarithm of the suspension chain (4) suspended at the bottom of the hanger (2);
-the starting point of the first hoist chain and the action of vibration or wind force when hoisting the reinforcement mesh (1)>The length between, determined by simulation or experiment, < >>；
-the starting point of the head sling and the end point of the head sling when lifting the reinforcing mesh (1)>Between (I)>The vibration or wind force is generated in the horizontal plane, namely +.>Distance of axis offset>Determined by simulation or experiment, < >>；
-reinforcement mesh (1) imitating string at any moment +.>Is +.>Is>，/>；
-coefficient of->；
-average tension by micro-vibrations in the longitudinal effective length of the reinforcement mesh (1), - ∈10>；
-first crane when lifting reinforcing mesh (1)The action of the chain starting point and the vibration or wind force>Tension caused by micro-vibration between +.>；
-end point of last hanging chain when lifting reinforcing mesh (1)>Is effective against vibration or wind force>Tension produced,/->；
-density of reinforcing mesh (1) per meter in longitudinal direction,/->；
-longitudinal tensile stiffness of the section of the reinforcement mesh (1), wherein->For the longitudinal tensile modulus of elasticity of the section, < >>Is the transverse cross section area of the reinforcing mesh (1)>；
-the reinforcing mesh (1) is affected by accidental vibration or wind force to generate vibration in the lifting process, when being placed on the reinforcing framework of the box girder body in the prefabricated box girder template, the horizontal plane generates wavy dislocation and the horizontal axis is +.>Maximum deviation value of>；
-the error value of the dislocation tolerance of the reinforcement mesh (1) placed on the reinforcement cage of the box girder body in the prefabricated box girder template,。
2. the prefabricated box girder roof reinforcement mesh lifting appliance according to claim 1, wherein the reinforcement mesh (1) is a thin planar structure formed by binding a plurality of longitudinal reinforcements (11) and a plurality of transverse reinforcements (12), and a plurality of hanging chain lifting points (42) which are connected with bottom end buckles (41) of corresponding hanging chains (4) in a buckling manner are arranged on the reinforcement mesh (1).
3. The prefabricated box girder top plate reinforcing steel mesh lifting appliance according to claim 1, wherein the steel frame girder lifting frame (2) comprises channel steel longitudinal beams (21) arranged at three corner points of the triangular steel frame girder and a plurality of groups of round steel web members (22) surrounding the channel steel longitudinal beams at the three corner points, the plurality of groups of round steel web members are distributed at equal intervals along the channel steel longitudinal beams, and the plurality of groups of round steel web members (22) are firmly welded with the channel steel longitudinal beams (21) at the three corner points.
4. The prefabricated box girder top plate reinforcing steel mesh lifting appliance is characterized in that the lifting chain (4) is a multi-section lifting chain formed by sequentially connecting oval steel rings connected with one another in a ring mode, and the buckles (41) are respectively arranged on the bottom of the lifting frame (2) and the oval steel ring at the bottommost end of the multi-section lifting chain (4).
5. The prefabricated box girder top plate reinforcing steel bar net hanger of claim 4, wherein the buckle (41) is an openable and self-locking buckling structure.
6. A method of operating a prefabricated box girder top panel reinforcement mesh sling according to claim 1, the method comprising the steps of:
step one, designing and manufacturing prefabricated box girder top plate reinforcing steel mesh lifting appliance
(1) Manufacturing a prefabricated box girder top plate reinforcing steel mesh hanger according to a design drawing of the box girder top plate reinforcing steel mesh (1);
(2) the bottom suspension of the hanging bracket (2) is calculated through a formula I, a formula II and a formula IIILength of the hanging chain (4)>Different initial conditions->String vibration function with reinforcing mesh (1)>Maximum amplitude, selecting the wave-shaped dislocation tolerance error ++of the reinforcing mesh (1) meeting the standard specification requirement>Chain length of +.>；
(3) On-site test verifies the length of the hanging chain (4)In the process, the maximum deviation of the wavy dislocation of the reinforcing mesh (1) is +.>Meets the standard specification requirements; if the requirements are not met, adjusting a plurality of pairs of buckles (41) at the bottom of the hanging frame connected with the next section or the next sections in the multi-section hanging chain of the plurality of pairs of hanging chains (4), shortening the length of the hanging chain, and performing test verification again until the requirements are met;
step two, binding reinforcing steel meshes of prefabricated box girder top plate
(1) Longitudinal steel bars (11) and transverse steel bars (12) of the intelligent steel bar processing steel bar net sheet (1) are bound and formed on a die carrier;
(2) checking the number and the spacing of longitudinal steel bars (11) and transverse steel bars (12) of the steel bar net sheet (1) and the binding firmness degree, wherein the number and the spacing are required to meet the design requirement;
step three, hoisting the reinforcing mesh into place and pouring box girder concrete
(1) Moving the travelling crane and the hanging frame (2) to the upper part of the binding mould frame of the reinforcing mesh (1), and correspondingly buckling and hanging the hanging chain hanging points (42) of the reinforcing mesh (1) by the buckles (41) at the bottom ends of the hanging chains (4);
(2) the travelling crane is operated to move the reinforcing steel bar net sheet (1) to be conveyed to a reinforcing steel bar framework of a box girder body in the prefabricated box girder template, and the reinforcing steel bar net sheet and the reinforcing steel bar framework of the box girder body are firmly bound;
(3) pouring box girder cement concrete, and curing to be qualified.
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| CN201810791644.5A CN108750915B (en) | 2018-07-18 | 2018-07-18 | Prefabricated box girder top plate reinforcing steel mesh lifting appliance and operation method |
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| KR20110127629A (en) * | 2011-09-28 | 2011-11-25 | (주)신원Rpc | Hanger type temporary resources for cantilever and method for construction of cantilever part of bridge using the temporary resources |
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