Installation method of ultra-high special-shaped tower in confined space of large-scale waste incineration power plant

Abstract

The invention relates to the field of on-site preparation, transportation or processing of building materials or building components, and specifically to a method for installing an ultra-high special-shaped tower in a confined space of a large-scale waste incineration power plant. A method for installing an ultra-high special-shaped tower in a confined space of a large-scale waste incineration power plant is characterized by: performing the following steps in sequence: I. installing the tower; II. hoisting the chimney steel structure. The invention has high installation accuracy and fast construction progress.

Description

Technical Field

[0001] The invention relates to the field of on-site preparation, transportation or processing of building materials or building components, and in particular to a method for installing an ultra-high special-shaped tower in a confined space of a large-scale waste incineration power plant. Background Art

[0002] With the development of national economy and professional technology, the owner has higher and higher requirements for the quality of building appearance. Different from the conventional waste incineration power plant, this project introduces a "large roof structure" to cover the main plant and auxiliary rooms as a whole, except for the environmental protection exhibition center. The design is guided by the principles of economy, practicality, beauty and modernity. Good design ideas and advanced design concepts are the basis of the entire design. Through the selection of architectural forms, color matching and the use of modern materials, the entire appearance and shape are rich, with clear layers and strong virtual and real contrast, reflecting the characteristics of modern industrial buildings that are stable but lively, grand but delicate.

[0003] This project uses the concept of "mountain" to introduce the concepts of mountain base, mountain body and mountain top into the design, and uses the height of chimney and modeling tower to shape the peak of the mountain. The chimney of this project adopts the form of reinforced concrete core + external steel frame, with a structural height of 106 meters. The modeling tower adopts steel support frame + oblique grid, with a building height of 142 meters, and a total of nearly 3,000 steel structure components. When the steel structure of the chimney and modeling tower was constructed, the surrounding monomer structure had been completed, and the construction plane and space were limited. The focus of this project is to solve the vertical transportation of steel structures in limited space and reduce the amount of high-altitude welding.

[0004] The chimney and the modeling tower of this project are attached with steel structures. The chimney steel structure is designed to be 14 stories high, and the modeling tower steel structure is designed to be 27 stories high. The highest building height reaches 142 meters, and it is a special-shaped structure. Due to the tilting and hoisting of the components and other suspended operations, special safety protection measures that are compatible with the installation of the components are required, which makes safety protection difficult. At the same time, due to the influence of factors such as structural height and installation errors, it is very difficult to accurately arrange the measurement control points and measure and correct the component installation.

[0005] At the same time, due to the tight construction plane and construction period of this project, there are serious cross-operations in the plane and elevation in the actual construction. In order to ensure that the auxiliary facilities around the chimney must be constructed synchronously at the production node, and the chimney and the steel structure of the modeling tower are ready for installation, the surrounding areas have been completed. Due to the limited plane and space, it is extremely difficult to position the crane for steel structure installation. The conventional steel structure hoisting construction process cannot meet the target demand of completing the installation of large-scale steel structures within a short construction period of this project. Summary of the invention

[0006] In order to overcome the defects of the prior art, a large-span steel structure construction method with high installation accuracy and fast construction progress is provided. The present invention discloses a method for installing an ultra-high special-shaped tower in a confined space of a large-scale waste incineration power plant.

[0007] The present invention achieves the purpose of the invention through the following technical solutions:

[0008] A method for installing an ultra-high special-shaped tower in a confined space of a large-scale waste incineration power plant, wherein the tower has a total of 27 floors, and the 1st to 10th floors of the tower, i.e., -4.5m to +44.545m, are pipe column frame structures, and the connection form adopts high-strength bolts and welding. The 11th to 27th floors, i.e., +44.545 to 133.715m, are steel pipe oblique grid structures, and the connection form adopts welding. The assembly precision is high, the height is up to about 140m, and the installation risk is high. After the layered offline modular assembly, the 1st to 10th floors are planned to be hoisted by a 350-ton crawler crane, and the 11th to 27th floors are planned to be hoisted by a 1,250-ton crawler crane.

[0009] The chimney has 1 to 14 floors, from -1 to 104 meters. The steel columns are box-type structures, the main steel beams are H-shaped steel structures, the outer ring steel beams are box-type structures, the horizontal supports are steel pipe structures, and the connection form is high-strength bolts plus welding. After layered offline modular assembly, it is planned to use 350-ton crawler cranes, 1250-ton crawler cranes and tower cranes for lifting.

[0010] Its characteristics are: it is implemented in sequence according to the following steps:

[0011] I. Install the modeling tower:

[0012] (I) Installation of steel structure from floors 1 to 9 of the modeling tower:

[0013] The 1st to 9th floors of the modeling tower, i.e. -4.5 to +38.5m, are installed using a single hoisting method. The crane uses a 350t crawler crane with a 48m main arm, a 42m auxiliary arm, a maximum operating radius of 38m, and a maximum component weight of 20 tons. After checking the hoisting performance table, the crane working conditions meet the hoisting requirements. The steel columns below +1.0m are installed in advance. The steel column joints are equipped with docking ear plates. Each steel column is equipped with four ear plates. The ear plates are made of 20mm steel plates, the connecting plates are made of 16mm steel plates, and the connecting bolts are M22 ordinary bolts.

[0014] (II) Installation of the 10-story steel structure of the modeling tower:

[0015] The elevation of the large roof from the 10th floor of the modeling tower to +44.545m is 43.55m, so the large roof directly above the modeling tower area needs to be installed before installing the 10th floor of the modeling tower;

[0016] (III) Steel structure installation of the 11th to 27th floors of the modeling tower:

[0017] The installation of the 11th to 16th floors of the modeling tower, i.e. +44.545 to +77.715m, adopts the overall assembly and hoisting of every two floors. The disconnection position is located 1.3m above the 12th floor. Before hoisting, the 11th to 12th floors are first assembled into a unit on the ground. To ensure accuracy, the size of the 10th floor should be measured before assembly, and the ground lofting and assembly should be carried out according to the size of the 10th floor. During assembly, the rods at the segmented parts are temporarily spot welded and fixed, and removed before hoisting. After the overall hoisting, they are hoisted separately. The next hoisting unit should be pre-assembled before hoisting, and the subsequent hoisting should be pre-assembled in sequence before installation.

[0018] The 17th to 18th floors of the modeling tower, i.e., +83.715 to +89.715m, are assembled into a whole hoist. The 19th to 23rd floors of the modeling tower, i.e., +95.715 to +107.715m, are assembled into a whole hoist. The 24th to 27th floors of the modeling tower, i.e., +123.215 to +133.715m, are assembled into a whole hoist.

[0019] (IV) Crane selection:

[0020] The main crane for the overall hoisting of the steel structure of the modeling tower is a 1,250-ton crawler crane with a main boom of 96m, a jib of 72m, a main boom angle of 85°, a maximum operating radius of 50m, a maximum hoisting height of about 158m, a super-lifting counterweight of 100 tons, and a maximum lifting weight of 101 tons, which can meet the hoisting construction requirements;

[0021] The weight and elevation of the 11th to 27th layers of the modeling tower are as follows:

[0022]

[0023] (V) Component assembly site and pre-assembly:

[0024] Combined with the actual situation on site and the pre-assembly requirements, two assembly sites were set up on site. The 11th to 27th floors of the modeling tower have different horizontal dimensions of components on each floor, so the assembly site is considered to use roadbed boxes for paving, and the paving position is adjusted according to the actual position. Before paving the roadbed box, 200mm thick crushed stone is used for replacement and compaction;

[0025] Before pre-assembly, a 1:1 layout is carried out on the roadbed box according to the actual size of the 10-story steel column installation. Steel pipes with the same specifications as the steel columns are used as tire frames. They are positioned according to the actual size and welded to the roadbed box after verification. The horizontal projection center line of the column is laid out on the roadbed box using a total station as the reference line for column assembly;

[0026] Before pre-assembly, check the size of each component and correct the components with size deviation first;

[0027] When the first column is hoisted, the horizontal projection center line of the ground is used for adjustment. After it is in place, it is spot welded with the frame first. 20a I-beam is used as a temporary support to fix the column. The subsequent columns are installed and fixed in this way. If the column height is less than 8m, the movable scaffolding is used as the operating platform for personnel. If the column height is greater than 8m, the disc-type scaffolding is used to set up the operating platform;

[0028] After the columns are completed and the dimensions are checked, the diagonal braces and horizontal braces can be installed;

[0029] To prevent deformation during welding and hoisting, the rods are first spot welded before the components are assembled. After the size is verified, a temporary fixed support is added. The temporary support is made of channel steel [14a. After the temporary support is erected, the component is welded. The temporary support can be removed only after the component hoisting and welding are completed.

[0030] (VI) Lifting point setting:

[0031] For floors 11 to 16, each lifting unit has 3 to 5 lifting points, for floors 17 to 21, 6 lifting points, and for floors 22 to 27, 3 to 4 lifting points.

[0032] (VII) Platform and ladder settings:

[0033] The 11th to 27th floors of the modeling tower are high-rise structures. For the pipe columns installed in sections, an operating platform and a ladder must be set up at the section interface before hoisting, which is conducive to the upper installation and welding. The steel ladder is directly welded on the bracket pipe column, and then the steel ladder is removed after the installation is completed. Before hoisting, the vertical up and down safety mother rope is fixed on the steel ladder, and the fall arrester is hung;

[0034] (VIII) High-altitude correction measures:

[0035] Pre-assemble on the ground before hoisting. There may be some deformation during the hoisting process. When the joints are misaligned, use jacks or wire ropes to make fine adjustments at the joints.

[0036] II. Hoisting chimney steel structure:

[0037] (I) Installation of chimney steel structure from 2nd to 6th floor:

[0038] The chimney 2 to 6 floors (+5m to +36m) are located below the steel structure roof, and the heaviest weight of a single component is about 2.7 tons. Depending on the actual hoisting position and height, a 25-ton or 50-ton truck crane or tower crane can be used for installation;

[0039] (ii) Installation of chimneys from 7th to 12th floors:

[0040] Since the 7th floor of the chimney, with an elevation of +45m, is located above the large roof in the CC area, and the elevation of the top of the slab is +43.55m, the 7th floor can only be installed after the large roof components are installed. It is difficult to use a car crane to lift the chimney components after the large roof is installed. The chimney components are mainly installed using a 7020 tower crane and a 1,250-ton crawler crane. The maximum operating radius of the tower crane is 40m. According to the 45m operating radius, the tower crane has a lifting capacity of 3.63 tons, which meets the lifting requirements;

[0041] After the large roof concrete is poured in this area, the floor slab can be used as a temporary component storage site. The components are first hoisted onto the large roof by a crane, and then installed using a tower crane and a 1,250-ton crawler crane. When the large roof floor slab is used as a component storage site, the components cannot be stacked together.

[0042] The present invention is applicable to spatial special-shaped structures, summarizes the vertical transportation of steel structures in confined spaces and the overall hoisting construction process after layered offline modular assembly to reduce the amount of high-altitude welding, and has the following beneficial effects: effectively ensuring the installation accuracy, accelerating the construction efficiency, and laying a good foundation for the smooth implementation of engineering projects. The special unconventional construction process effectively ensures the installation accuracy, accelerates the construction efficiency, and also provides important reference materials for the construction of steel structures similar to waste incineration plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a schematic diagram of the BIM model of the present invention,

[0044] Figure 2 is a schematic diagram of a BIM model of a chimney in the present invention,

[0045] Figure 3 It is a schematic diagram of the BIM model of the modeling tower in the present invention.

[0046] Figure 4 It is a structural schematic diagram of the shaping tower in the present invention,

[0047] Figure 5 Schematic diagram of the structure of the chimney in the present invention,

[0048] Figure 6 It is a schematic diagram of the structure of the 11th to 12th floors of the modeling tower in the present invention.

[0049] Figure 7 It is a schematic diagram of the structure of the 13th to 14th floors of the modeling tower in the present invention.

[0050] Figure 8 It is a schematic diagram of the structure of the 15th to 16th floors of the modeling tower in the present invention.

[0051] Fig. 9 It is a schematic diagram of the structure of the 17th to 18th floors of the modeling tower in the present invention.

[0052] Fig.10 It is a schematic diagram of the structure of the 19th to 21st floors of the modeling tower in the present invention.

[0053] Fig.11 It is a schematic diagram of the structure of the 22nd to 23rd floors of the modeling tower in the present invention.

[0054] Fig.12 It is a schematic diagram of the structure of the 24th to 27th floors of the modeling tower in the present invention.

[0055] Fig.13 and Fig.14 All of them are schematic diagrams of the arrangement of the columns in the present invention.

[0056] Fig.15 is a schematic diagram of a hoisting column in the present invention,

[0057] Fig.16 is a schematic diagram of temporary support in the present invention,

[0058] Fig.17 This is a schematic diagram of the center of gravity and the length of the steel wire rope of the 11th to 12th floors of the modeling tower in the present invention.

[0059] Fig.18 This is a schematic diagram of the center of gravity and the length of the steel wire rope of the 17th to 18th floors of the modeling tower in the present invention.

[0060] Fig.19 This is a schematic diagram of the center of gravity and the length of the steel wire rope of the 22nd to 23rd floors of the modeling tower in the present invention.

[0061] Fig. 20 It is a schematic diagram of the ladder arrangement in the present invention,

[0062] Fig.21 is a schematic diagram of the operating platform configuration in the present invention,

[0063] Fig. 22 It is a schematic diagram of the arrangement of the straight ladder in the present invention. DETAILED DESCRIPTION

[0064] The present invention is further described below by means of specific examples. Example

[0065] A method for installing an ultra-high special-shaped tower in a confined space of a large waste incineration power plant. Figure 1 As shown, the molding tower is as Figure 3 and Figure 4As shown, there are 27 floors in total. The 1st to 10th floors of the modeling tower, i.e. -4.5m to +44.545m, are pipe column frame structures, connected by high-strength bolts and welding. The 11th to 27th floors, i.e. +44.545 to 133.715m, are steel pipe oblique grid structures, connected by welding, with high assembly precision requirements, a maximum height of about 140m, and high installation risks. After layered offline modular assembly, the 1st to 10th floors are planned to be hoisted by a 350-ton crawler crane, and the 11th to 27th floors are planned to be hoisted by a 1,250-ton crawler crane.

[0066] Chimney Figure 2 and Figure 5 As shown, there are 1 to 14 floors, i.e. -1 to 104m. The steel columns are box-type structures, the main steel beams are H-shaped steel structures, the outer ring steel beams are box-type structures, the horizontal supports are steel pipe structures, and the connection form is high-strength bolts plus welding. After layered offline modular assembly, it is planned to use 350-ton crawler cranes, 1250-ton crawler cranes and tower cranes for lifting.

[0067] In order to solve the problem of vertical transportation of steel structures and reduce the amount of high-altitude welding, a solution of layered offline modular assembly followed by overall hoisting is adopted, which is implemented in the following steps:

[0068] I. Install the modeling tower:

[0069] (I) Installation of steel structure from floors 1 to 9 of the modeling tower:

[0070] The 1st to 9th floors of the modeling tower, i.e. -4.5 to +38.5m, are installed using a single hoisting method. The crane uses a 350t crawler crane with a 48m main arm, a 42m auxiliary arm, a maximum operating radius of 38m, and a maximum component weight of 20 tons. After checking the hoisting performance table, the crane working conditions meet the hoisting requirements. The steel columns below +1.0m are installed in advance. The steel column joints are equipped with docking ear plates. Each steel column is equipped with four ear plates. The ear plates are made of 20mm steel plates, the connecting plates are made of 16mm steel plates, and the connecting bolts are M22 ordinary bolts.

[0071] (II) Installation of the 10-story steel structure of the modeling tower:

[0072] The elevation of the large roof from the 10th floor of the modeling tower to +44.545m is 43.55m, so the large roof directly above the modeling tower area needs to be installed before installing the 10th floor of the modeling tower;

[0073] (III) Steel structure installation of the 11th to 27th floors of the modeling tower:

[0074] like Figure 6 to Figure 8As shown: The installation of the 11th to 16th floors of the modeling tower, that is, +44.545 to +77.715m, adopts the overall assembly and hoisting of every two floors. The disconnection position is located 1.3m above the 12th floor. Before hoisting, the 11th to 12th floors are first assembled into a unit on the ground. To ensure accuracy, the size of the 10th floor should be measured before assembly, and the ground lofting and assembly should be carried out according to the size of the 10th floor. During assembly, the rods at the segmented parts are temporarily spot welded and fixed, and removed before hoisting. After the overall hoisting, they are hoisted separately. The next hoisting unit should be pre-assembled before hoisting, and the subsequent hoisting should be pre-assembled in sequence before installation.

[0075] like Fig. 9 As shown: The 17th to 18th floors of the modeling tower, i.e., the second floor from +83.715 to +89.715m, are assembled into an integral hoisting, such as Fig.10 and Fig.11 As shown: the 19th to 23rd floors of the modeling tower, i.e., +95.715 to +107.715m, are assembled into an integral hoisting. Fig.12 As shown: the 24th to 27th floors of the modeling tower, i.e. the four floors from +123.215 to +133.715m, are assembled into an integral hoisting;

[0076] (IV) Crane selection:

[0077] The main crane for the overall hoisting of the steel structure of the modeling tower is a 1,250-ton crawler crane with a main boom of 96m, a jib of 72m, a main boom angle of 85°, a maximum operating radius of 50m, a maximum hoisting height of about 158m, a super-lifting counterweight of 100 tons, and a maximum lifting weight of 101 tons, which can meet the hoisting construction requirements;

[0078] The weight and elevation of the 11th to 27th layers of the modeling tower are as follows:

[0079]

[0080] (V) Component assembly site and pre-assembly:

[0081] Combined with the actual situation on site and the pre-assembly requirements, two assembly sites were set up on site. The 11th to 27th floors of the modeling tower have different horizontal dimensions of components on each floor, so the assembly site is considered to use roadbed boxes for paving, and the paving position is adjusted according to the actual position. Before paving the roadbed box, 200mm thick crushed stone is used for replacement and compaction;

[0082] like Fig.13 and Fig.14 As shown: before pre-assembly, a 1:1 layout is carried out on the roadbed box according to the actual size of the 10-story steel column installation, and a steel pipe with the same specifications as the steel column is used as a tire frame. It is positioned according to the actual size and welded to the roadbed box after verification. The horizontal projection center line of the column is laid out on the roadbed box using a total station as the reference line for column assembly;

[0083] Before pre-assembly, check the size of each component and correct the components with size deviation first;

[0084] like Fig.15 As shown: When the first column is hoisted, it is adjusted using the center line of the horizontal projection of the ground. After it is in place, it is first spot welded with the tire frame. 20a I-beams are used as temporary supports to fix the columns. The subsequent columns are installed and fixed in this way in sequence. If the column height is less than 8m, a movable scaffolding is used as a personnel operating platform. If the column height is greater than 8m, a disc-type scaffolding is used to set up the operating platform.

[0085] After the columns are completed and the dimensions are checked, the diagonal braces and horizontal braces can be installed;

[0086] To prevent deformation during welding and hoisting, the rods are first spot welded before the components are assembled. After the size is verified, a temporary fixed support is added. The temporary support is made of channel steel [14a. After the temporary support is erected, the component is welded. The temporary support can be removed only after the component hoisting and welding are completed.

[0087] Temporary support such as Fig.16 shown.

[0088] (VI) Lifting point setting:

[0089] For floors 11 to 16, each lifting unit has 3 to 5 lifting points, for floors 17 to 21, 6 lifting points, and for floors 22 to 27, 3 to 4 lifting points.

[0090] The center of gravity and wire rope length of the 11th to 12th layers are as follows Fig.17 As shown, the center of gravity and wire rope length of the 17th to 18th layers are as follows Fig.18 As shown, the center of gravity and wire rope length of the 22nd to 23rd layers are as follows Fig.19 shown.

[0091] (VII) Platform and ladder settings:

[0092] The 11th to 27th floors of the modeling tower are high-rise structures. For the pipe columns installed in sections, an operating platform and a ladder must be set up at the section interface before hoisting, which is conducive to the upper installation and welding. The steel ladder is directly welded on the bracket pipe column, and then the steel ladder is removed after the installation is completed. Before hoisting, the vertical up and down safety mother rope is fixed on the steel ladder, and the fall arrester is hung;

[0093] Ladder settings such as Fig. 20 As shown, the operating platform is set up as Fig.21 shown.

[0094] (VIII) High-altitude correction measures:

[0095] Pre-assembly is carried out on the ground before lifting. There may be certain deformation during the lifting process. When the joints are misaligned, jacks or wire ropes are used at the joints for fine-tuning.

[0096] II. Hoisting chimney steel structure:

[0097] (I) Installation of chimney steel structure from 2nd to 6th floor:

[0098] The chimney 2 to 6 floors (+5m to +36m) are located below the steel structure roof, and the heaviest weight of a single component is about 2.7 tons. Depending on the actual hoisting position and height, a 25-ton or 50-ton truck crane or tower crane can be used for installation;

[0099] (ii) Installation of chimneys from 7th to 12th floors:

[0100] Since the 7th floor of the chimney, with an elevation of +45m, is located above the large roof in the CC area, and the elevation of the top of the slab is +43.55m, the 7th floor can only be installed after the large roof components are installed. It is difficult to use a car crane to lift the chimney components after the large roof is installed. The chimney components are mainly installed using a 7020 tower crane and a 1,250-ton crawler crane. The maximum operating radius of the tower crane is 40m. According to the 45m operating radius, the tower crane has a lifting capacity of 3.63 tons, which meets the lifting requirements;

[0101] After the large roof concrete is poured in this area, the floor slab can be used as a temporary component stacking site. The components are first hoisted onto the large roof by a crane, and then installed using a tower crane and a 1,250-ton crawler crane. When the large roof floor slab is used as a component stacking site, the components cannot be stacked together;

[0102] Modeling Tower Figure 4 As shown, the chimney steel structure is as follows Figure 5 shown.

[0103] III. Construction technical requirements:

[0104] (I) Safety control measures for climbing operations

[0105] For on-site climbing, use the straight ladder in the channel in the design drawings, and the straight ladder is installed together with each layer of components.

[0106] Straight ladder settings Fig. 22 shown.

[0107] (1) The ladder should be securely fixed and a lifeline should be installed on the side. Climbers should wear safety belts and use fall arresters when climbing the ladder.

[0108] (2) A safety rope is installed on the operating platform and construction workers should hang their safety belts on the safety rope when working.

[0109] (3) A safety net must be installed under the operating platform and must extend beyond the edge of the operating plane.

[0110] (II) Monitoring and surveillance measures

[0111] After the integrally assembled components above the 11th floor of the modeling tower are hoisted, the hoisting shall be stopped when they are 200 to 300 mm above the ground, and the following contents shall be monitored:

[0112] (1) After lifting, monitor whether there is any deformation. If there is any deformation, stop lifting and reinforce it;

[0113] (2) After lifting, monitor whether the lifting equipment and wire rope are normal;

[0114] (3) Monitor the stability of the crane and whether the foundation where the crane is located has subsided;

[0115] (4) Monitor the rotation range of the suspended object to see if there are any obstacles that would prevent it from rotating into place.

[0116] V. Quality Control

[0117] 1. Adopting technical standards

[0118] (1) Laws and regulations:

[0119] Contract Law of the People's Republic of China

[0120] Environmental Protection Law of the People's Republic of China

[0121] Production Safety Law of the People's Republic of China

[0122] Construction Law of the People's Republic of China

[0123] Construction Project Quality Management Regulations

[0124] Construction Project Safety Production Management Regulations

[0125] "Safety Production License Regulations"

[0126] (2) National standards:

[0127] "Steel Structure Design Standard" GB50017-2017

[0128] "Steel Structure Engineering Construction Code" GB50755-2012

[0129] "Code for Acceptance of Construction Quality of Steel Structure Engineering" GB50205-2020

[0130] Code for Welding of Steel Structures GB50661-2011

[0131] Code for Loads on Building Structures GB50009-2012

[0132] Engineering Surveying Specification GB50026-2007

[0133] "Construction Project Management Code" GB / T50326-2017

[0134] Code for Seismic Design of Buildings GB5011-2015

[0135] 《Fire retardant coating for steel structure》 GB14907-2018

[0136] "Unified Technical Specification for Construction Safety" GB50870-2013

[0137] "Technical Specification for Fire Safety at Construction Sites" GB50720-2011

[0138] (3) Industry Association Standards:

[0139] "Technical Regulations for Safety in the Use of Construction Machinery" JGJ33-2012

[0140] Technical Specifications for Safety of Height Operations in Construction JGJ80-2016

[0141] "Technical Specifications for Temporary Electricity Safety at Construction Sites" JGJ46-2005

[0142] "Technical Specifications for Safety of Hoisting in Construction" JGJ276-2012

[0143] "Technical Code for Fire Protection of Building Steel Structures" CECS200:2006.

[0144] 2. Quality assurance measures during the construction phase should strengthen control before, during and after the construction, especially focusing on comprehensive control of important factors that affect the quality of the project entity, such as people, machines, materials, methods, and environment. Focus on the implementation of the following systems.

[0145] (1) Regular quality meetings and quality review system

[0146] The operation team holds a weekly production meeting. The operation team leader puts quality review on the important agenda of the meeting. In addition to arranging production tasks, he also needs to make a comprehensive summary of the construction quality dynamics of the previous week, point out the quality problems existing in the construction and the measures to solve these problems. The measures should be practical and operational, and a meeting minutes should be formed so that the implementation can be checked item by item at the next regular meeting. Before each new task starts, the project professional technicians organize the construction team to conduct technical briefings and clarify the allowable range of installation deviations. Before starting work every day, the operation team leader will explain the construction tasks of the day. Every time and every day, the briefing records are kept for reference.

[0147] (2) Three-inspection system

[0148] Self-inspection: After the completion of each sub-project, the construction team must conduct self-inspection of the constructed products.

[0149] Mutual inspection: For sub-projects that have passed the self-inspection, the foreman will organize the upstream and downstream construction teams to conduct mutual inspection under the organization of the quality inspector. Any problems found during the mutual inspection must be solved seriously and promptly by the upstream team.

[0150] Special inspection (handover inspection): The upper and lower shifts conduct mutual inspection and determine that the quality of the sub-project meets the acceptance standards. Both parties fill out the handover inspection record. Only after it is signed and approved by the project department's full-time quality inspector and the general contractor (owner) engineer can the next process be carried out.

[0151] 3. Quality assurance measures for lifting operations

[0152] (1) Before the crane enters the site, the crane’s safety and technical performance must be inspected in cooperation with Party A. Only after passing the inspection can the crane enter the site for lifting operations.

[0153] (2) Before lifting, the dimensions of steel components and deformation of steel materials should be rechecked. If any unqualified ones are found, they should be corrected immediately and lifted only after being checked and approved by professional designers to avoid delaying the construction.

[0154] (3) When a crane enters the construction site, the soil compaction degree, crane lifting and braking system, etc. must be checked before lifting. Lifting can only be carried out after the lifting test has been completed and all inspections are correct.

[0155] (4) Before lifting with a crane, carefully confirm that the component hooks are fully fixed. Any illegal or irregular operations are strictly prohibited to ensure the safety of the lifting process.

[0156] (5) Before the crane starts lifting, it should ensure that there are no construction workers around the component to be lifted before giving the lifting signal and then starting the lifting.

[0157] (6) After each column is hoisted, it should be aligned immediately, the error should be checked, and reported to professional designers for inspection before proceeding to the next construction process.

[0158] (7) Components used in lifting operations must not be cut or arbitrarily cut. If necessary, the consent of professional designers must be obtained first.

[0159] (8) Arrange the delivery of components to site and stack them in an orderly and regular manner to avoid repeated transportation.

[0160] 4. Quality Inspection

[0161] (1) The foundation elevation and center should be checked according to the control points to see if they meet the size requirements of the drawing.

[0162] 1) Assemble and install the roof truss, strictly control the column distance and span to facilitate the installation of components in the next process.

[0163] 2) The factory building structure construction must comply with the "Code for Construction and Acceptance of Steel Structure Engineering" (GB50205-2001).

[0164] (2) Permissible deviation items and inspection methods for main structure installation:

[0165]

[0166] VI. Benefit Analysis

[0167] 1. Social benefits

[0168] The layered offline modular splicing and hoisting construction method was successfully applied in a renewable energy utilization center project, and the social benefits obtained are as follows:

[0169] (1) Due to the limited plane and space, it is extremely difficult to position the crane for steel structure installation. The conventional steel structure hoisting construction process cannot meet the target requirement of completing the installation of large-scale steel structures within a short construction period. In order to solve the problem of vertical transportation of steel structures and reduce the amount of high-altitude welding, a solution of overall hoisting after layered offline modular assembly is adopted, which has higher operation efficiency and safer construction process.

[0170] (2) The project involved installation and construction of more than 50,000 tons of steel structure. The application of this technology successfully shortened the construction period of key processes by about 24 days, thus gaining valuable time for the subsequent roof structure construction of the project.

[0171] 2. Economic benefits

[0172]

[0173] The present invention is applied to a certain renewable energy utilization center project, with a total incineration scale of 3,800t / d. It has both garbage treatment and power generation functions and is a harmless disposal project for domestic garbage. According to the requirements of the project landscape design, the concept of "mountain" is used to introduce the concepts of mountain base, mountain body and mountain top into the modeling design, and the height of the chimney and the modeling tower is used to shape the peak of the mountain. The chimney of the project adopts a reinforced concrete core + external steel frame form with a structural height of 106 meters. The modeling tower adopts a steel support frame + oblique grid, with a building height of 142 meters and a total of nearly 3,000 steel structure components. During the construction of the chimney and modeling tower steel structure, due to the limited construction plane and space, the vertical transportation of the steel structure in the confined space and the overall hoisting construction process after the layered offline modular assembly that reduces the amount of high-altitude welding are summarized, which effectively guarantees the installation accuracy and speeds up the construction efficiency, laying a good foundation for the smooth implementation of the project, and also providing important reference materials for the installation of super-high special-shaped steel structures in similar projects.

Claims

1. A method for installing an ultra-high special-shaped tower in a confined space of a large-scale waste incineration power plant, wherein the tower has a total of 27 floors, wherein the 1st to 10th floors, i.e., -4.5m to +44.545m, are pipe column frame structures, connected in the form of high-strength bolts and welding, and the 11th to 27th floors, i.e., +44.545 to 133.715m, are steel pipe oblique grid structures, connected in the form of welding, The chimney has 1 to 14 floors, i.e. -1 to 104 meters. The steel columns are box-type structures, the main steel beams are H-shaped steel structures, the outer ring steel beams are box-type structures, the horizontal braces are steel pipe structures, and the connection form is high-strength bolts plus welding. Its characteristics are: Follow the steps below to implement: I. Install the modeling tower: (I) Installation of steel structure from floors 1 to 9 of the modeling tower: The 1st to 9th floors of the modeling tower, i.e. -4.5 to +38.5m, are installed by a single hoisting method. The crane adopts a 350t crawler crane, with a 48m main arm, a 42m auxiliary arm, a maximum operating radius of 38m, and a maximum component weight of 20 tons. The steel columns below +1.0m are installed in advance, and docking ear plates are set at the joints of the steel columns. Each steel column is equipped with four ear plates. The ear plates are made of 20mm steel plates, the connecting plates are made of 16mm steel plates, and the connecting bolts are M22 ordinary bolts. (II) Installation of the 10-story steel structure of the modeling tower: The elevation of the large roof from the 10th floor of the modeling tower to +44.545m is 43.55m, so the large roof directly above the modeling tower area needs to be installed before installing the 10th floor of the modeling tower; (III) Steel structure installation of the 11th to 27th floors of the modeling tower: The installation of the 11th to 16th floors of the modeling tower, i.e. +44.545 to +77.715m, adopts the overall assembly and hoisting of every two floors. The disconnection position is located 1.3m above the 12th floor. Before hoisting, the 11th to 12th floors are first assembled into a unit on the ground. To ensure accuracy, the size of the 10th floor should be measured before assembly, and the ground lofting and assembly should be carried out according to the size of the 10th floor. During assembly, the rods at the segmented parts are temporarily spot welded and fixed, and removed before hoisting. After the overall hoisting, they are hoisted separately. The next hoisting unit should be pre-assembled before hoisting, and the subsequent hoisting should be pre-assembled in sequence before installation. The 17th to 18th floors of the modeling tower, i.e., the second floors from +83.715 to +89.715m, are assembled into an integral hoist; the 19th to 23rd floors of the modeling tower, i.e., the third floors from +95.715 to +107.715m, are assembled into an integral hoist; the 24th to 27th floors of the modeling tower, i.e., the fourth floors from +123.215 to +133.715m, are assembled into an integral hoist; (IV) Crane selection: The main crane for the overall hoisting of the steel structure of the modeling tower is a 1,250-ton crawler crane with a main boom of 96m, a jib of 72m, a main boom angle of 85°, a maximum operating radius of 50m, a maximum hoisting height of 158m, a super-lifting counterweight of 100 tons, and a maximum hoisting weight of 101 tons, which can meet the hoisting construction requirements; The weight and elevation of the 11th to 27th layers of the modeling tower are as follows: ； (V) Component assembly site and pre-assembly: Combined with the actual situation on site and the pre-assembly requirements, two assembly sites are set up on site. The 11th to 27th floors of the modeling tower have different horizontal dimensions of components on each floor. Therefore, the assembly site considers using roadbed boxes for paving. The paving position is adjusted according to the actual position. Before paving the roadbed box, 200mm thick crushed stone is used for replacement and compaction. Before pre-assembly, a 1:1 layout is carried out on the roadbed box according to the actual size of the 10-story steel column installation. Steel pipes with the same specifications as the steel columns are used as tire frames. They are positioned according to the actual size and welded to the roadbed box after verification. The horizontal projection center line of the column is laid out on the roadbed box using a total station as the reference line for column assembly; Before pre-assembly, check the size of each component and correct the components with size deviation first; When the first column is hoisted, the horizontal projection center line of the ground is used for adjustment. After it is in place, it is spot welded with the frame first. 20a I-beam is used as a temporary support to fix the column. The subsequent columns are installed and fixed in sequence in this way. If the column height is less than 8m, the movable scaffolding is used as the operating platform for personnel. If the column height is greater than 8m, the disc-type scaffolding is used to set up the operating platform. After the columns are completed and the dimensions are checked, the diagonal braces and horizontal braces can be installed; To prevent deformation during welding and hoisting, the rods are first spot welded before the components are assembled. After the dimensions are verified, temporary fixed supports are added. The temporary supports are made of channel steel [14a. After the temporary supports are erected, the components are welded. The temporary supports can be removed only after the hoisting and welding of the components are completed. (VI) Lifting point setting: For floors 11 to 16, each lifting unit has 3 to 5 lifting points, for floors 17 to 21, 6 lifting points, and for floors 22 to 27, 3 to 4 lifting points. (VII) Platform and ladder settings: The 11th to 27th floors of the modeling tower are high-rise structures. For the pipe columns installed in sections, an operating platform and a straight ladder must be set up at the section interface before hoisting, which is conducive to the upper installation and welding. The steel ladder is directly welded on the bracket pipe column, and then the steel ladder is removed after the installation is completed. Before hoisting, the vertical up and down safety mother ropes are fixed on the steel ladder, and the fall arrester is hung; (VIII) High-altitude correction measures: Pre-assemble on the ground before lifting. When there is misalignment at the joints, use jacks or wire ropes to make fine adjustments at the joints. II. Hoisting chimney steel structure: (I) Installation of chimney steel structure from 2nd to 6th floor: The chimney 2 to 6 floors, i.e. +5m to +36m, are located below the steel structure roof. The heaviest weight of a single component is 2.7 tons. Depending on the actual hoisting position and height, a 25-ton or 50-ton truck crane or tower crane can be used for installation. (II) Installation of chimneys from 7th to 12th floors: Use a crane to lift the components onto the large roof first, then use a tower crane and a 1,250-ton crawler crane to install them. When the large roof floor is used as the component stacking site, the components cannot be stacked together.

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