CN110528891B

CN110528891B - Integral hoisting method for large-span spherical net rack

Info

Publication number: CN110528891B
Application number: CN201910843298.5A
Authority: CN
Inventors: 曹谦; 胡申林; 李阳; 李克; 陈维; 马亮
Original assignee: Chengdu Construction First Construction Engineering Co ltd
Current assignee: Chengdu Construction First Construction Engineering Co ltd
Priority date: 2019-09-06
Filing date: 2019-09-06
Publication date: 2021-04-16
Anticipated expiration: 2039-09-06
Also published as: CN110528891A

Abstract

The invention discloses an integral hoisting method for a large-span spherical net rack, which adopts a mode of combining integral hoisting and sectional hoisting to hoist the large-span spherical net rack, wherein the upper chord and the lower chord of the upper net rack are integrally lofted on the ground through a total station to be integrally assembled, a reserved value of the arching height is made in the assembling process, the upper net rack is integrally lifted and installed through a plurality of hoisting devices, an operation platform is formed by utilizing the upper structure of the integral hoisting, the lower structure adopts the sectional assembling, the sectional hoisting and the connection to form an integral body, the high-altitude bulk loading of components is reduced, the using amount of scaffolds is reduced, the high-altitude operation amount is reduced, the construction is safe and reliable, the construction risk is reduced, the construction work efficiency is improved, and the control of the net rack quality and the control of the safe production are facilitated.

Description

Integral hoisting method for large-span spherical net rack

Technical Field

The invention belongs to the technical field of building construction, and particularly relates to an integral hoisting method for a large-span spherical net rack.

Background

Under the rapid development of continuous innovation in the building industry, the requirements of people on buildings are not limited to functionality, usability and economy, and more unique appearance modeling requirements are pursued, and new times of trend and building characteristics are reflected. The large-span space spherical net rack is deeply favored by the modern building industry due to the characteristics of light weight, large rigidity, large span, flexible arrangement, beautiful and elegant appearance and the like.

At present, the installation method of the large-span space spherical net rack is as follows: and (3) assembling and welding the small units, then hoisting and transporting the small units to a high-altitude assembling and splicing preparation site, and performing high-altitude assembling and welding from the outer edge to the inner ring. A complete large-span space spherical net rack relates to thousands of small units to make such hoist and mount process need a large amount of scaffold cooperations, work efficiency is low, and in the work progress, can't guarantee the quality and the safety in production of engineering.

Disclosure of Invention

The invention aims to provide an integral hoisting method for a large-span spherical net rack, which aims to solve the technical problems that the working efficiency is low and the engineering quality and the safety production cannot be ensured in the hoisting process of the conventional large-span spherical net rack.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the integral hoisting method for the large-span spherical net rack comprises the following steps:

(1) measuring and paying off, adopting a total station coordinate lofting, and marking the position of a lower chord sphere;

(2) assembling an upper net rack, arranging a steel pipe jig frame with the same diameter as the sphere at the position of the lower chord sphere, setting the height of the steel pipe jig frame according to the maximum distance of the sphere to 20cm, and assembling the upper net rack on the steel pipe jig frame;

(3) assembling and checking the upper-layer net rack, detecting 50% of welding seams by adopting nondestructive inspection, checking whether the overall appearance size and the spherical nodes are consistent with the position of a drawing, and whether the pre-camber of the net rack meets the design requirements of a deepening drawing, performing anticorrosion treatment after meeting the requirements, and not checking and changing according to the steps (2) to (3);

(4) integrally hoisting an upper net frame, performing anti-corrosion treatment after the upper net frame is qualified, then jointly hoisting the upper net frame to a support position by adopting a plurality of cranes in a matching manner, taking the upper net frame in place through a chain block and a jack detail, and measuring by adopting a total station, a level meter, a theodolite and an infrared distance meter;

(5) fixing the fulcrum of the upper-layer net rack, welding the upper-layer net rack and the support to fix the upper-layer net rack after the thin part of the upper-layer net rack is in place, and taking welding protection measures;

(6) assembling and hoisting the lower-layer net rack in sections, installing an electric hoist at the corresponding position of the upper-layer net rack, hoisting each section of the lower-layer net rack through the electric hoist, fixing the sections by adopting reverse connection after the sections are hoisted in place, and controlling local deviation by adopting a pull rope;

(7) connecting an upper net rack and a lower net rack, after the lower net rack is hoisted in place and fixed, welding the upper net rack and the lower net rack by adopting a hanging basket, making a welding protection measure, and arranging a safety channel and an anti-falling net below the hanging basket;

(8) and (4) acceptance and delivery, namely measuring the flexibility value of the net rack, detecting the length deviation of the longitudinal side and the transverse side of the net rack, detecting the center deviation and the height deviation of the supporting point, detecting 50% of welding seams by adopting nondestructive inspection and all documents involved in the acceptance construction process, and completing delivery after the documents are qualified.

Preferably, in the step (2), the upper-layer net rack assembling process includes the following steps:

the method comprises the following steps: installing a lower limit sphere on the steel pipe jig;

step two: the lower chord balls are connected through the lower chord to form a grid-shaped lower chord grid;

step three: each lower chord grid is provided with a web member which is connected with the central point of the lower chord grid by four corners and is vertically arranged above the central point, and an upper chord ball is arranged on the web member;

step four: the upper chord balls are connected through the upper chord to form a grid-shaped upper chord grid, and a more stable basic unit is assembled;

step five: the basic units obtained according to the contents of steps one to four are welded together.

Preferably, in the step (2), the nodes are firstly reinforced and welded, the lower chord nodes are welded, then the upper chord nodes are welded, and all welding is symmetrically and uniformly performed.

Preferably, in the step (4), the crane weight display is used for hoisting the upper-layer net rack integrally, when the net rack is hoisted in advance, the hoisting weight of each crane is read in a stable state, the load weight of each crane is kept in the hoisting process to ensure the stability of the net rack in the integral hoisting process, when the hoisting height of the net rack exceeds the target elevation by 1 meter, the net rack is horizontally moved again, is slowly put down after being horizontally moved to the position of the support, and is put in place through the chain block and the thin part of the jack.

Preferably, in step (8), the average value of the measured deflection in the acceptance and delivery standard is not more than 5% of the design value.

Preferably, in the step (8), the allowable value of the length deviation of the longitudinal side and the transverse side in the acceptance delivery standard is 1/2000 of the length and is not more than 30 mm; the allowable center offset value is 1/3000 of the span of the rack and is not more than 30 mm; allowable height deviation value: 1/400 which is the distance between adjacent points of the net rack supported by the periphery is not more than 15mm, and 30mm is the distance between the highest point and the lowest point; for the multipoint-supported net rack, the distance between the adjacent supports is 1/800 mm and is not more than 30 mm.

Preferably, in step (8), the acceptance delivery related file includes: the construction drawing, completion drawing, design change file, construction organization design, quality certificate and test report of steel and other materials; the method comprises the steps of obtaining part product qualification certificates and test reports of the net rack, accepting records of all procedures of net rack splicing, certification of qualified examination of welders, quality inspection data of welding seams and high-strength bolts, and records of geometric dimension errors and deflection after the net rack is totally spliced in place.

Preferably, in the step (8), after the nondestructive inspection is qualified, the sample is delivered according to delivery standards after antiseptic treatment.

Compared with the prior art, the invention has the following beneficial effects:

1. the large-span spherical net rack is hoisted by adopting a mode of combining integral hoisting and sectional hoisting, the upper chord and the lower chord of the upper net rack are integrally lofted on the ground through a total station, the integral assembly is carried out, the reserved value of the arching height is made in the assembling process, the upper net rack is integrally hoisted and installed through a plurality of hoisting devices, an operation platform is formed by utilizing the upper structure of the integral hoisting, the lower structure is assembled in sections, hoisted and connected to form an integral body, the number of components which are bulk-packed at high altitude is reduced, the number of scaffolds is reduced, the high-altitude operation amount is reduced, the construction is safe and reliable, the construction risk is reduced, the construction work efficiency is improved, and the control of the net rack quality and the control of safe production;

2. the invention adopts the total station, the level meter, the theodolite and the infrared distance meter, and controls the three-dimensional space coordinates of the nodes by using the ground permanent mark points, thereby ensuring the installation precision of the net rack and facilitating the installation of the net rack in high altitude.

3. The invention is mainly used for ground welding construction, which is beneficial to controlling the quality of welding seams, thereby ensuring the installation quality of the net rack;

4. the invention adopts the grid deepening design, estimates the deformation of the grid, controls the disturbance of the grid, calculates the arching height and reduces the installation deformation of the grid.

Drawings

FIG. 1 is a schematic flow diagram of the present invention;

FIG. 2 is an installation diagram of a first upper-layer net rack assembly step;

FIG. 3 is an installation diagram of the second upper-layer net rack assembling step;

FIG. 4 is an installation diagram of the third step of assembling the upper layer net rack;

FIG. 5 is an installation diagram of the fourth step of assembling the upper layer of racks;

FIG. 6 is an installation diagram of the fifth step of assembling the upper layer net rack;

FIG. 7 is an installation diagram of a sixth step of assembling the upper layer net rack;

FIG. 8 is an installation diagram of a seventh upper net rack assembling step;

fig. 9 is an installation schematic diagram of an upper-layer net rack assembling step eight;

FIG. 10 is an installation diagram of the ninth step of assembling the upper net rack;

fig. 11 is an installation schematic diagram of an upper-layer net rack assembling step ten;

FIG. 12 is a schematic view of the vertical force distribution of the lifting point and the crane;

fig. 13 is a sectional view of the suspension steel structure plane rod and the ball joint.

Detailed Description

The present invention is further illustrated by the following examples, which include, but are not limited to, the following examples.

Example 1

This embodiment major structure is located between Sichuan self-trade district Chuan nan Lin harbor piece district headquarters base 1A # building and 1B # building, mainly comprises two parts of dull and stereotyped face rack and suspension rack. The structure form is as follows: the square pyramid plane net rack is placed orthogonally, and the node type is a welding ball. The support form is as follows: and the lower chord is supported in multiple points. Whole rack is supported by 8 supports, supports the interval: the length direction 64.55m and the width direction is about 6.6 m. The installation height of the steel net rack is 42.4 m.

The steel net rack is in a special shape, the maximum length is 64.55m, the maximum width is 17.6m, the maximum height is 13.65m, the actual coverage area is 890 square meters, the steel net rack belongs to a large-span spatial structure, and the total weight is about 75 tons. The supporting mode is a lower chord multi-point supporting mode, and the rise of the upper layer of net rack is 4.0 m. The lower net rack is 9.65m high.

Firstly, preparing construction before hoisting:

1) and after the steel structure deepening design drawing is agreed by the original design unit, carrying out factory machining on the component according to the deepening drawing.

2) And (5) checking and accepting the component transportation site. Checking the size, the number and the specification of the approach components; a number of the check member; and (5) checking the quality certification of the raw materials and a test report.

3) Compiling a special construction scheme and technology:

a. the method changes the installation process of the original design stress system, such as integral hoisting points, layered integral hoisting and the like, whether local reinforcement is needed or not is rechecked, and the approval is given by the original design unit.

b. If the construction method belongs to dangerous and large projects with a certain scale, the special construction scheme can be organized and implemented after expert demonstration.

4) Preparation of constructors and machines.

5) The construction site is hardened by C30 concrete with the thickness of 200mm, so that the bearing capacity of the foundation in the installation area of the net rack can meet the requirement.

Secondly, the hoisting process is shown in figure 1 and comprises the following steps:

measuring and paying off: and (4) adopting a total station, lofting coordinates, releasing the position of the lower chord sphere, and arranging the steel tube jig frame with the same diameter as the sphere.

(II) assembling an upper-layer net rack:

the method comprises the following steps: arranging and leveling a platform support according to the figure 2, wherein all the positions of the lower chord balls adopt steel pipes (the wall thickness is 10mm) with the same diameter of the ball body as an installation jig frame, and the height of the steel pipes is arranged according to the maximum distance of the ball body to the ground by 20 cm;

step two: installing a lower string ball according to the figure 3;

step three: connecting the lower chord as shown in FIG. 4;

step four: mounting the web member and the upper chord ball according to the figure 5; (setting angle steel truss jig on the spin-ball position by coordinate measurement)

Step five: connecting the second grid upper chords and web members as shown in FIG. 6;

step six: as shown in fig. 7, two grids are installed as a basic unit;

step seven: as shown in fig. 8, the basic unit is enlarged;

step eight: mounting the web member as shown in fig. 9;

step nine: as shown in fig. 10, a more stable basic unit is assembled;

step ten: the basic cell is enlarged as shown in FIG. 11;

by the above method: and integrally assembling the upper and lower chords of the upper-layer net rack.

And (3) welding the net rack, namely reinforcing and welding the nodes, welding the lower chord nodes, and welding the upper chord nodes, wherein all welding methods adopt symmetrical and uniform welding.

(III) assembling and checking the upper-layer net rack:

1. all welds of the net rack, which are extracted by 50%, are detected by adopting nondestructive inspection, and are subjected to antiseptic treatment after the detection is qualified, so that the net rack can be hoisted.

2. And checking whether the overall appearance size of the net rack and the spherical nodes are consistent with the positions of the drawings.

3. And checking whether the pre-camber of the net rack meets the design requirements of the deepened drawing.

(IV) integrally hoisting the upper-layer net rack:

the net rack adopts a construction method of ground splicing and integral hoisting. And respectively checking the setting of the hoisting point and the stability of the hoisting point part, providing a basis for safe hoisting construction, and performing stress checking. And 3 automobile cranes are integrally lifted and hoisted for construction from the headquarters base engineering of the trade area according to comprehensive factors such as the form, the characteristics, the size, the weight, the field conditions and the like of the grid structure. Each crane is provided with 2 hoisting points. The specific hoisting point position checking and crane position is shown in fig. 12 below.

The vertical stress calculation results of the lifting points are shown in the table 1:

table 1 vertical stress meter with hanging point

The hoisting process utilizes the crane weight display, when the net rack is hoisted in advance, the hoisting weight of each crane is read in a stable state, and the load weight of each crane is kept in the hoisting process, so that the stability of the net rack in the whole hoisting process is ensured. When the net rack lifting height exceeds the target elevation by 1 meter, the net rack moves horizontally again, and the net rack slowly lowers after moving horizontally to the position of the support. The jack detail is in place by the chain block. Measurements were made using a total station, a level, a theodolite, an infrared rangefinder.

(V) fixing the supporting point of the upper net rack:

and after the details of the net rack are in place, welding the support, wherein welding protection measures are taken due to high-altitude welding.

(VI) assembling and hoisting the lower-layer net rack in sections:

as shown in fig. 13, the lower rack is divided into 6 sub-groups, each group 1, 6 weighing about 1 ton, and each group 2, 3, 4, 5 weighing about 2.6 tons. Grouping 1, 6 adopt 25 tons of electric block, grouping 2, 3, 4, 5 adopt 45 tons of electric block hoists, the electric block is installed under the rack that the structure corresponds hangs down the ball position. Before hoisting, four corners of the lower chord of each group are provided with pull ropes to hoist in place, and then are fixed by reverse connection, and if local deviation exists, the pull ropes are used for controlling. Monitoring equipment is arranged on the 1A-1 axis of the No. 1A building and the 9 layers of the 1BC-U axis of the No. 1B building to monitor the verticality and the flatness of the steel structure.

(VII) connecting the upper and lower layers of net racks:

and after the hoisting is in place, welding connection is implemented by adopting a hanging basket. When welding or electric welding and cutting at high altitude, an operator should be equipped with a slag receiving barrel to prevent welding slag and cut metal or sparks from falling down to hurt people. And welding windproof measures are taken. When connecting and hanging the steel construction jib, set up 900mm wide 225 meters long design steel springboard safe passageways between the net rack lower suspension rod spare before hanging and establishing the string basket, the passageway both sides adopt the steel pipe to set up the guardrail, net rack lower suspension ball and member lower part are fully hung and are prevented weighing down the net.

The height of the position is 42.4 meters, and operators can directly go to the safe passage on the roofs of the No. 1A building and the No. 1B building.

After the piece-separating suspension steel structure is connected with the net rack, a 900mm wide and 115 m long shaped steel springboard safety channel is arranged on the suspension structure when the part under the butt-joint suspension steel structure is suspended, the two sides of the channel are provided with guardrails by adopting steel pipes, and the anti-falling net is fully hung on the suspension ball under the net rack and the lower part of the rod piece. The hanging basket is provided with the anti-falling clamp at the position of the hook during manufacturing so as to prevent the hook from loosening and falling off, and the protective facility is well finished and then hung and hung to weld the hanging basket.

(eighth) acceptance and delivery:

after the construction is finished, the deflection value of the net rack (including the deflection of the net rack due to self weight and the deflection of the finished roof engineering) is measured, the average value of the measured deflection is not more than 5% of the design value, and the measured deflection curve is filed. Deflection observation point of net rack: for small span, it is set at one point in the middle of lower chord, for large span, it can set five points, one point in the middle of lower chord, two points at four points of two downward lower chord spans, and for three-way net frame, it should measure the deflection at three four points of each span.

During the inspection, the length deviation of the vertical and horizontal sides of the net rack, the center deviation and the height deviation of the supporting points are inspected. The allowable value of the length deviation of the longitudinal side and the transverse side should be 1/2000 of the length, and should not be more than 30 mm; the center offset allowance should be 1/3000 for rack span and should not be greater than 30 mm; allowable height deviation value: 1/400 between adjacent points of the net rack supported by the periphery is equal to the distance between adjacent supports, and is not larger than 15mm, and 30mm is between the highest point and the lowest point; for a multipoint support rack, 1/800 should be the distance between adjacent supports and should not be greater than 30 mm.

The acceptance of the net rack project should have the following documents: the construction drawing, completion drawing, design change file, construction organization design, quality certificate and test report of steel and other materials; the method comprises the steps of obtaining part product qualification certificates and test reports of the net rack, accepting records of all procedures of net rack splicing, certification of qualified examination of welders, quality inspection data of welding seams and high-strength bolts, and records of geometric dimension errors and deflection after the net rack is totally spliced in place.

Performing nondestructive inspection on 50% of all welding seams according to the standard requirement of the secondary welding seams. And (5) after flaw detection is qualified, performing antiseptic treatment. And handing over the owner according to the delivery standard.

Third, the materials and devices involved in this embodiment include:

materials: welding balls, steel structure rods, anticorrosive paint, welding wires, safety nets and steel gangboards;

the material requirements are as follows:

1. the variety, specification, performance and the like of the steel products meet the requirements of the current national standard and design.

2. The variety, specification, performance and the like of the welding material meet the requirements of the current national standard and design.

3. The materials and welding wires should be retested for physical, chemical and mechanical properties strictly according to the requirements of GB/T700-2006, GB/T14957, GB/T8110, GB/T10045 and GB/T17493.

4. The carbon dioxide gas used in the gas shielded welding is in accordance with the regulations of the current industry standard HG/T2537.

5. The steel ball should meet the requirements of steel mesh frame welding ball joint JG/T11-2009, and the allowable deviation of the geometric dimension of the welded hollow ball is shown in Table 2:

geometric tolerance deviation of welded hollow sphere table 2

The ball should be subjected to mechanical tests, and the ultimate bearing capacity should be specified in JG/T11-2009. The ribbed ball and ribbed plate should be in the plane of the upper and lower chords.

6. The position of the positioning axis of the steel grid structure support and the specification of the support embedded part meet the design requirements. When the upper layer of net rack is arranged at the position of the support, the deviation of the center of the support to the positioning axis is not more than 10 mm.

7. The allowable deviations in the position, elevation, levelness and position of the support surface ceiling should comply with the specifications of table 3.

Allowable deviation (mm) of support surface top plate and support seat anchor bolt positions table 3

8. The allowable deviation of the minor key unit should meet the specifications of Table 4

Tolerance deviation (mm) of small splicing unit

TABLE 4

9. After the steel mesh frame structure is assembled and the roof engineering is finished, the disturbance values of the steel mesh frame structure and the roof engineering are measured respectively, and the measured disturbance values are not more than 1.15 times of those of the corresponding design.

10. After the steel mesh frame structure is installed, the surfaces of the nodes and the rod pieces of the steel mesh frame structure are clean and have no obvious scars, silt and dirt. The bolt ball joint should be tightly embedded with all seams by oil putty, and the redundant screw holes should be sealed.

11. After the steel frame structure is installed, the allowable deviation of the installation of the steel frame structure is in accordance with the specification of table 5.

Tolerance deviation (mm) of steel grid structure installation

TABLE 5

12. The allowable length deviation of the seamless steel pipe fitting is +/-1 mm, the allowable deviation of the height of a single piece is +/-2 mm, the allowable deviation of an upper chord diagonal line is +/-3 mm, the center deviation of upper and lower chord nodes is 2mm, when the length of a splitting or blocking net rack unit is not more than 20m, the allowable deviation of the length of a splicing side is +/-10 mm, when the length of a strip or block is more than 20m, the allowable deviation of the length of the splicing side is +/-20 mm, accurate paying-off is required before the total assembly, and the allowable deviation of paying-off is 1/10000 of the side length and the diagonal line length respectively.

13. The welding is carried out according to the requirements of GB50205 'Steel Structure engineering construction and acceptance Standard'. And (3) performing 20% ultrasonic flaw detection on the tensile crater (but actually expanding to 50% ultra-detection in construction), and requiring a secondary welding seam. The appearance detection of the welding seam generally adopts visual inspection.

14. Rust removal treatment should be carried out on various parts of the steel grid structure, and the rust removal grade reaches Sa2.5 grade; the on-site paint repairing and rust removing tool adopts electric and pneumatic rust removing tools to completely remove rust, reaches St3 grade and reaches the roughness of 35 to 55 um. And coating after the experience collection lattice.

15. The thickness of the coating layer is required, the thickness of the epoxy zinc-rich primer dry film is 60um, the thickness of the epoxy micaceous iron intermediate paint dry film is 120um, and the thickness of the polyurethane finish dry film is 60 um. The paint should have good compatibility with the fire-retardant coating. The anti-corrosion primer has good adhesion effect with the base material, and the adhesion force of the anti-corrosion primer with the base material is not less than 5 MPa.

16. The environment temperature during coating is preferably 5-38 ℃, and the relative humidity is not more than 85%. When the surface of the component has dew, the coating cannot be applied, and outdoor operation cannot be performed in rainy and snowy days. Can not be drenched with rain within 4h after coating

Equipment: the device comprises a hoisting crane, an electric hoist, a total station, a theodolite, a level gauge, an infrared distance meter, a falling protector and a hanging basket.

Fourthly, the safety measures adopted by the embodiment are as follows:

1. comply with the relevant regulations in the high-altitude operation safety technical regulations for building construction JGJ 80-2016 and the national standard GB 6067.1-2010 safety regulations for hoisting machinery.

2. All scaffolds and set-up brackets must be accepted before use.

2. Workers (including apprentices, trainees and civilians) who add the engineering construction need to know the safety technical operation rules of the engineering, and should insist on the working posts and forbid the operation after drinking in the operation.

3. One worker must go through three levels of safety education and must have safety operation certificates for operators of special work categories such as electricians, electrogas welders, crane drivers and large power equipment.

4. The construction safety technology responsibility engineers take care of safety cautions and collective operation work every day according to the construction characteristics of the day, the operation individuals need to be clearly separated, and special persons need to uniformly command and coordinate in the operation.

5. The machine tool equipment is required to be safe and reliable, and is provided with special people for regular maintenance. Windlasses, electric welders, cranes, etc. stored in rainy seasons or in the open air need to be covered without rain leakage or water flooding, operators check the grounding condition of a power supply before using the windlasses, electric welders, etc. to check the insulation condition regularly. The consumer is acceptably grounded. A leakage protector is required. The special equipment is operated by a person specially.

6. The electric lines (temporary lines) and electric equipment are required to be handled by electricians and other people cannot move around. A leakage protector must be provided using the power tool. The shell of the outdoor electric machine must be well grounded, rain-proof and moisture-proof measures are taken, the electric machine stands on the insulating plate when in use, and a living area is provided with enough fireproof facilities.

7. Tools used during operation are placed into the tool bag conveniently, walkways, channels and climbing tools during operation are cleaned at any time, and disassembled materials and waste materials are cleaned and transported away in time and cannot be randomly arranged or discarded downwards. The article is delivered to inhibit casting.

8. And setting a safety net and edge protection according to the requirements of the scheme.

9. The high-altitude operation must be carried with safety helmet and safety belt, otherwise the construction is not carried out.

10. A warning belt is arranged below the projection of the net rack, and specially-assigned persons are arranged to watch.

11. And establishing a safety duty system. The project team has a leader on each shift to be responsible for safety duty.

12. And (3) establishing a safety responsibility system, wherein each class is provided with two full-time safety officers except one leader responsible for field safety, and the security officers are controlled in a partitioned mode.

13. Strictly preventing objects falling from high altitude as a safety key of construction enhances intersection monitoring.

Fifthly, the environmental protection measures adopted by the embodiment are as follows:

1. aiming at establishing a civilized construction demonstration construction site, the civilized construction management responsibility system is implemented, the civilized construction is put at the same position with the quality and the safety of the engineering, and the civilized construction is carried out.

2. The field construction machines and tools must be arranged according to the specified positions of the general plane arrangement diagram, and tools, materials, semi-finished products and other classification specifications are orderly stacked.

3. The construction water, electricity and pipeline installation must meet the regulations, the installation arrangement is neat, any wire pulling and electricity connection are forbidden, and the night construction must have enough illumination.

4. The on-site office production equipment is required to keep clean and tidy, attractive and timely clear and recycle scattered materials and tools before receiving work every day, so that the work is finished, the work is clear, the work is finished.

5. The special personnel are arranged on the site to take charge of the security work, the non-construction personnel are prohibited from entering, the tool materials must meet the regulated procedures when entering and leaving the field, and the financial equipment has anti-theft measures.

The above examples are only one of the preferred embodiments of the present invention, and should not be used to limit the scope of the present invention, but all the technical problems solved by the present invention should be consistent with the present invention, and should be included in the scope of the present invention, unless there is any meaningful change or retouching in the spirit and concept of the subject invention.

Claims

1. The integral hoisting method for the large-span spherical net rack is characterized by comprising the following steps of:

2. The method of claim 1, wherein in the step (2), the upper grid assembly process comprises the steps of:

3. The method of claim 2, wherein in step (2), the reinforcement welding is performed on the nodes first, the lower chord node is welded first, and then the upper chord node is welded, and all welding is performed symmetrically and uniformly.

4. The method as claimed in claim 1, wherein in the step (4), the upper net rack is hoisted integrally by using a crane weight display, when the net rack is hoisted in advance, the hoisting weight of each crane is read in a stable state, the load weight of each crane is kept in the hoisting process to ensure the stability of the net rack in the integral hoisting process, when the hoisting height of the net rack exceeds 1m of the target elevation, the net rack is moved horizontally, is slowly put down after being moved horizontally to the position of the support, and is put in place through the chain block and the thin part of the jack.

5. The method of claim 1, wherein in step (8), the average measured deflection in the acceptance delivery criteria is no greater than 5% of the design value.

6. The method as claimed in claim 1, wherein in the step (8), the acceptance delivery standard has a permissible value of length deviation of the longitudinal and transverse sides of 1/2000 mm and not more than 30 mm; the allowable center offset value is 1/3000 of the span of the rack and is not more than 30 mm; allowable height deviation value: 1/400 which is the distance between adjacent points of the net rack supported by the periphery is not more than 15mm, and 30mm is the distance between the highest point and the lowest point; for the multipoint-supported net rack, the distance between the adjacent supports is 1/800 mm and is not more than 30 mm.

7. The method of claim 1, wherein in step (8), the acceptance of the file involved in the delivery comprises: the construction drawing, completion drawing, design change file, construction organization design, quality certificate and test report of steel materials; the method comprises the steps of obtaining part product qualification certificates and test reports of the net rack, accepting records of all procedures of net rack splicing, certification of qualified examination of welders, quality inspection data of welding seams and high-strength bolts, and records of geometric dimension errors and deflection after the net rack is totally spliced in place.

8. The method according to claim 1, wherein in the step (8), after the nondestructive inspection is passed, the specimen is delivered according to delivery standards after antiseptic treatment.