A method for reverse construction of a large-span steel structure roof

Abstract

This invention provides a reverse construction method for large-span steel structure roofs, belonging to the field of building construction technology. This method involves: construction personnel constructing a BIM model of the large-span steel structure roof according to design drawings; optimizing the BIM model based on the actual construction location of the large-span steel structure roof to minimize structural deformation during construction; fixing the structural foundation of the large-span steel structure roof based on the optimized BIM model; installing the prefabricated steel structure on the structural foundation and connecting the steel structure to the foundation; laying an insulation layer on the surface of the steel structure; laying a waterproof layer on the insulation layer; and laying asphalt concrete on the waterproof layer. This method solves the problem of frequent adjustments to construction steps based on actual conditions during the construction of large-span steel structure roofs, which affects construction efficiency.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology, and specifically relates to a method for reverse construction of a large-span steel structure roof. Background Technology

[0002] Large-span steel structure roofs refer to roof systems with large spans constructed using steel structural components. They offer advantages such as lightweight, high strength, and good seismic performance, and are widely used in industrial plants, stadiums, and exhibition centers. The main components of large-span steel structure roofs are made of steel, commonly including steel beams, steel columns, and steel trusses. These steel structural materials possess high strength and rigidity, enabling them to withstand large-span loads and exhibiting good deformation resistance and seismic performance. Structural design is crucial for large-span steel structure roofs, including load calculations, structural layout, and node design. Through rational structural design, the steel structure roof can maintain strength and rigidity while reducing the impact of structural self-weight and loads on the structure, thus improving overall structural performance. The construction process for large-span steel structure roofs involves preparation, installation organization, and welding connections. During construction, the construction sequence must be rationally arranged according to the design drawings and construction plan to ensure accurate installation and connection of the structure. Since large-span steel structure roofs are typically exposed to various climatic conditions and environmental corrosion, anti-corrosion protection treatment is essential. Common anti-corrosion methods include coating protection, hot-dip galvanizing, and spraying anti-corrosion agents to extend the service life of steel structures. Large-span steel structure roofs can also improve their energy efficiency through energy-saving design. For example, the design of roof components should consider the installation of insulation layers, ventilation, and lighting to reduce energy loss and improve the comfort of the indoor space. Construction safety is a critical issue for large-span steel structure roofs, requiring the development of detailed construction organization and safety plans, and the implementation of corresponding safety measures to ensure the safety of construction personnel.

[0003] The construction process for existing large-span steel structure roofs is often adjusted according to the actual situation, which affects construction efficiency. Summary of the Invention

[0004] In view of this, the present invention provides a reverse construction method for large-span steel structure roofs, which can solve the problem that the construction steps are often adjusted according to the actual situation during the construction of large-span steel structure roofs, thus affecting the construction efficiency.

[0005] This invention is implemented as follows:

[0006] This invention provides a method for reverse construction of a large-span steel structure roof, comprising the following steps:

[0007] S10: Construction workers build a BIM model of the large-span steel structure roof according to the design drawings;

[0008] S20: Construction personnel optimize the BIM model of the large-span steel structure roof based on the actual construction location of the large-span steel structure roof to ensure that structural deformation can be minimized during construction.

[0009] S30: Fix the structural foundation of the large-span steel structure roof according to the optimized BIM model of the large-span steel structure roof;

[0010] S40: Install the prefabricated steel structure on the structural foundation of the large-span steel structure roof, and fasten the steel structure to the structural foundation;

[0011] S50: Lay an insulation layer on the surface of the steel structure to reduce heat reflection of the steel structure and improve the insulation performance of the large-span steel structure roof;

[0012] S60: A waterproof layer is laid on the insulation layer to prevent moisture from penetrating into the house and to improve the waterproof performance of the large-span steel structure roof.

[0013] S70: Asphalt concrete is laid on the top of the waterproof layer as the surface layer of the large-span steel structure roof to improve the wear resistance, waterproofness and wind resistance of the large-span steel structure roof.

[0014] S80: After the construction of the large-span steel structure roof is completed, structural inspection and reinforcement work shall be carried out to ensure the stability and safety of the roof structure.

[0015] The technical advantages of the reverse construction method for large-span steel structure roofs provided by this invention are as follows: By constructing a BIM model of the large-span steel structure roof according to the design drawings, the construction process of the large-span steel structure roof can be designed in advance, improving construction efficiency; by optimizing the BIM model of the large-span steel structure roof based on the actual construction location, structural deformation can be minimized during construction, ensuring the smooth progress of the large-span steel structure roof construction process. This solves the problem of frequent adjustments to construction steps based on actual conditions during existing large-span steel structure roof construction, which affects construction efficiency; by fixing the structural foundation of the large-span steel structure roof based on the optimized BIM model, the structural foundation of the large-span steel structure roof is ensured. The stability and safety of the roof are ensured through: the prefabricated steel structure is installed on the structural foundation of the large-span steel structure roof, and the steel structure is securely connected to the foundation; an insulation layer is laid on the surface of the steel structure to reduce heat reflection and improve the thermal insulation performance of the large-span steel structure roof; a waterproof layer is laid on top of the insulation layer to prevent moisture from penetrating the roof, thus improving its waterproof performance; asphalt concrete is laid on top of the waterproof layer as the surface layer of the large-span steel structure roof to improve its wear resistance, waterproofness, and wind resistance; and structural inspection and reinforcement are carried out after the completion of the large-span steel structure roof construction to ensure the stability and safety of the roof structure.

[0016] Based on the above technical solution, the reverse construction method for a large-span steel structure roof of the present invention can be further improved as follows:

[0017] The specific steps for optimizing the BIM model of the large-span steel structure roof based on its actual construction location to ensure minimal structural deformation during construction include:

[0018] The first step is for construction workers to obtain detailed information about the actual construction location, including ground coordinates, building location, and surrounding environment.

[0019] The second step involves the construction team analyzing the BIM model of the large-span steel structure roof to determine the adjustments needed to the shape, size, and location of the roof.

[0020] The third step involves the construction team creating a new BIM model based on the BIM model of the large-span steel structure roof and the adjustments made to the shape, size, and position of the roof.

[0021] The fourth step involves the construction workers adjusting the elements in the new BIM model to adapt it to the actual construction location during the creation process.

[0022] Fifth, the construction personnel used the optimized BIM model of the large-span steel structure roof to simulate the construction process;

[0023] The sixth step involves the construction team adjusting the construction plan based on the simulation results to reduce structural deformation.

[0024] The specific steps for construction workers to build a BIM model of the large-span steel structure roof according to the design drawings include:

[0025] The first step involves the construction personnel classifying the design drawings, installation locations, support points, and support methods of the large-span steel structure roof into hierarchical categories, and proposing a coding rule based on information organization to code each part of the large-span steel structure roof.

[0026] The second step involves the construction team standardizing the parameters of each part of the large-span steel structure roof and creating a shared parameter file for use in different families and projects.

[0027] The third step involves the construction personnel inputting the shared parameter file into the Graphisoft Archicad software platform. Based on the design drawings, installation locations, support points, and support methods of the large-span steel structure roof, they construct three-dimensional models of each part of the large-span steel structure roof, classify and summarize the three-dimensional models, and establish the large-span steel structure roof family library.

[0028] The fourth step involves the construction personnel calling upon various components from the large-span steel structure roof family library based on the actual installation situation of the large-span steel structure roof. Through external data file driving, they modify the structural parameters of the large-span steel structure roof and generate corresponding instances.

[0029] The fifth step involves the construction workers assembling the components in a unified manner to create a complete BIM model of the large-span steel structure roof.

[0030] Furthermore, the specific steps taken by the construction personnel during the creation of the new BIM model to adjust the elements in the new BIM model to adapt to the actual construction location include:

[0031] The first step is for the construction personnel to determine the type and extent of deformation of the large-span steel structure roof;

[0032] The second step involves the construction team determining and adjusting the element parameters in the new BIM model.

[0033] Third, during the creation of the new BIM model, the construction workers adjusted the curvature of the large-span steel structure roof by adjusting the curvature slider and setting smoothing parameters to adapt to the actual construction location.

[0034] Furthermore, the specific steps taken by the construction personnel to adjust the construction plan based on the simulation results to reduce structural deformation include:

[0035] The first step is for the construction personnel to establish a model based on finite element analysis, define the construction stages, select load combinations for each part of the large-span steel structure roof, and conduct stress analysis on structures with different curvatures and their combinations.

[0036] The second step involves the construction personnel establishing important node models of the large-span steel structure roof based on the optimized BIM model and finite element model, and comparing the stress performance and failure modes of the nodes on their respective platforms.

[0037] The third step involves the construction personnel using BIM model technology to calculate the weight of the components of the large-span steel structure roof, selecting an installation method, and analyzing the stress state of the components in each scheme based on finite element analysis.

[0038] The fourth step involves the construction team creating dynamic construction simulations for each scheme based on the BIM model of the large-span steel structure roof.

[0039] The fifth step involves the construction team integrating all stress data from each scheme with dynamic construction simulations to select the appropriate construction scheme.

[0040] Furthermore, the specific steps for fixing the structural foundation of the large-span steel structure roof based on the optimized BIM model of the large-span steel structure roof include:

[0041] The first step is for the construction personnel to analyze the stress points of the large-span steel structure roof based on the optimized BIM model of the roof.

[0042] The second step involves the construction workers selecting five points from the stress points as primary stress points and setting the rest as secondary stress points.

[0043] The third step is for the construction workers to fix the support columns at the corresponding positions of the main stress points;

[0044] Fourth, the construction workers fix the steel structure components at the corresponding positions of the auxiliary stress points. The support columns and the steel structure components form the structural foundation of the large-span steel structure roof.

[0045] Furthermore, the specific steps taken by the construction personnel to analyze the stress points of the large-span steel structure roof based on the optimized BIM model include:

[0046] The first step is for construction workers to import the BIM model of the large-span steel structure roof into Graphisoft Archicad software for stress analysis.

[0047] The second step involves the construction workers adding various loads to the large-span steel structure roof and adjusting the parameters of the loads.

[0048] The third step involves the construction personnel performing calculations and analyses on the BIM model of the large-span steel structure roof based on the Graphisoft Archicad software under load conditions to obtain the stress points of the large-span steel structure roof.

[0049] Furthermore, the specific steps for the construction personnel to select 5 points as primary stress points and the rest as secondary stress points include:

[0050] Based on the environment of the actual construction location of the large-span steel structure roof, the construction personnel selected 5 points as the main stress points. There were no obstacles at the main stress points in the actual construction location of the large-span steel structure roof. The remaining stress points were set as auxiliary stress points.

[0051] Furthermore, the specific steps for installing the prefabricated steel structure on the structural foundation of the large-span steel structure roof and for securely connecting the steel structure to the structural foundation include:

[0052] The first step is to determine the location and dimensions of the steel structure, and then position and adjust it according to the location of the structural foundation;

[0053] The second step is to inspect the surface of the steel structure to ensure that there are no defects or scratches.

[0054] The third step is to install the steel structure base and fix the steel structure to the foundation of the structure.

[0055] The fourth step is to install the steel structure frame and fasten the steel structure frame to the structural foundation of the steel structure roof with bolts.

[0056] Fifth step, install the steel structure beams, connect the steel structure beams to the steel structure frame, and fasten them with bolts;

[0057] Step 6: Install the steel structure panel. Install the structure panel onto the steel structure beam and fasten it with bolts.

[0058] Step 7: Install the steel structure space frame, connect the space frame to the steel structure roof, and securely connect the steel structure to the structural foundation.

[0059] Furthermore, the insulation layer comprises three layers: a fiberglass layer, an extruded polystyrene board layer, and an insulation coating layer. The fiberglass layer is fixedly connected to the steel structure by rivets. The extruded polystyrene board layer is disposed between the fiberglass layer and the insulation coating layer and is fixedly connected by adhesive. The insulation coating layer is disposed on the side of the extruded polystyrene board layer away from the fiberglass layer.

[0060] The adhesive comprises: 25-30 parts polyacrylamide, 15-22 parts sodium silicate, 5-8 parts filler, 6-8 parts additives, 3-6 parts heat-insulating agent, 2.5-4 parts surfactant, 23-28 parts acetone, and 40-45 parts water.

[0061] The additive is a mixture of sodium chromate, nonylphenol polyoxyethylene ether, and p-toluenesulfonic acid, with a weight ratio of sodium chromate:nonylphenol polyoxyethylene ether:p-toluenesulfonic acid of 1:5-7:3.5-5.

[0062] Furthermore, the thermal insulation coating layer is one of microporous polystyrene, expanded perlite, or organic polymer composite thermal insulation materials.

[0063] Compared with existing technologies, the beneficial effects of the reverse construction method for large-span steel structure roofs provided by this invention are as follows: Firstly, by constructing a BIM model of the large-span steel structure roof according to design drawings, construction personnel can pre-design the construction process, thus improving construction efficiency. Secondly, by optimizing the BIM model of the large-span steel structure roof based on its actual construction location, structural deformation can be minimized during construction, ensuring the smooth progress of the construction process. This solves the problem of frequent adjustments to construction steps based on actual conditions, which affects construction efficiency in existing large-span steel structure roof construction. Thirdly, by fixing the structural foundation of the large-span steel structure roof based on the optimized BIM model, the structural foundation of the large-span steel structure roof can be guaranteed. The stability and safety of the large-span steel structure roof are ensured through: the prefabricated steel structure is installed on the structural foundation of the large-span steel structure roof, and the steel structure is securely connected to the foundation; an insulation layer is laid on the surface of the steel structure to reduce heat reflection and improve the thermal insulation performance of the large-span steel structure roof; a waterproof layer is laid on top of the insulation layer to prevent moisture from penetrating the roof, thus improving its waterproof performance; asphalt concrete is laid on top of the waterproof layer as the surface layer of the large-span steel structure roof to improve its wear resistance, waterproofness, and wind resistance; and structural inspection and reinforcement are carried out after the completion of the large-span steel structure roof construction to ensure the stability and safety of the roof structure. Attached Figure Description

[0064] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 This is a flowchart illustrating the operation of a reverse construction method for a large-span steel structure roof. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0067] like Figure 1 The diagram shows an operation flowchart of a reverse construction method for a large-span steel structure roof provided by this invention. The method includes the following steps:

[0068] S10: Construction workers build a BIM model of the large-span steel structure roof according to the design drawings;

[0069] S20: Construction personnel optimize the BIM model of the large-span steel structure roof based on the actual construction location of the large-span steel structure roof to ensure that structural deformation can be minimized during construction.

[0070] S30: Fix the structural foundation of the large-span steel structure roof based on the optimized BIM model of the large-span steel structure roof;

[0071] S40: Install the prefabricated steel structure on the structural foundation of the large-span steel structure roof, and fasten the steel structure to the structural foundation.

[0072] S50: Lay an insulation layer on the surface of the steel structure to reduce heat reflection and improve the insulation performance of large-span steel structure roofs;

[0073] S60: A waterproof layer is laid on the insulation layer. The waterproof layer is used to prevent water from penetrating into the house and improve the waterproof performance of the large-span steel structure roof.

[0074] S70: Asphalt concrete is laid on top of the waterproof layer as the surface layer of the large-span steel structure roof to improve the wear resistance, waterproofness and wind resistance of the large-span steel structure roof.

[0075] S80: After the construction of the large-span steel structure roof is completed, structural inspection and reinforcement work shall be carried out to ensure the stability and safety of the roof structure.

[0076] During construction, the workers build a BIM model of the large-span steel structure roof according to the design drawings. The BIM model is then optimized based on the actual construction location of the large-span steel structure roof to minimize structural deformation during construction. The structural foundation of the large-span steel structure roof is then fixed based on the optimized BIM model. The prefabricated steel structure is installed on the structural foundation, and the steel structure is securely connected to the foundation. An insulation layer is laid on the surface of the steel structure to reduce heat reflection and improve its insulation performance. A waterproof layer is then laid on top of the insulation layer to prevent moisture from penetrating the roof and improve its waterproof performance. Asphalt concrete is laid on top of the waterproof layer as the surface layer of the large-span steel structure roof to improve its wear resistance, waterproofing, and wind resistance. After the construction of the large-span steel structure roof is completed, structural inspection and reinforcement work are carried out to ensure the stability and safety of the roof structure.

[0077] Among the above technical solutions, the specific steps for optimizing the BIM model of the large-span steel structure roof based on the actual construction location to ensure that structural deformation is minimized during construction include:

[0078] The first step is for construction workers to obtain detailed information about the actual construction location, including ground coordinates, building location, and surrounding environment.

[0079] The second step involves the construction team analyzing the BIM model of the large-span steel structure roof to determine the adjustments needed for the roof's shape, size, and location.

[0080] The third step involves the construction team creating a new BIM model based on the existing BIM model of the large-span steel structure roof, as well as adjustments to the roof's shape, size, and location.

[0081] The fourth step involves construction workers adjusting the elements in the new BIM model to suit the actual construction location during the creation of the new BIM model.

[0082] The fifth step involves the construction team using the optimized BIM model of the large-span steel structure roof to simulate the construction process.

[0083] The sixth step involves the construction team adjusting the construction plan based on the simulation results to reduce structural deformation.

[0084] The specific steps for construction workers to build a BIM model of a large-span steel structure roof according to the design drawings include:

[0085] The first step involves the construction team classifying the design drawings, installation locations, support points, and support methods of the large-span steel structure roof into hierarchical categories. They then propose a coding rule based on information organization to encode each part of the large-span steel structure roof.

[0086] The second step is for construction personnel to standardize the parameters of each part of the large-span steel structure roof, create a shared parameter file, and use it in different families and projects.

[0087] The third step involves the construction personnel inputting the shared parameter file into the Graphisoft Archicad software platform. Based on the design drawings, installation locations, support points, and support methods of the large-span steel structure roof, they construct three-dimensional models of each part of the large-span steel structure roof, classify and summarize the three-dimensional models, and establish a large-span steel structure roof family library.

[0088] The fourth step involves the construction personnel calling upon various components from the large-span steel structure roof family library based on the actual installation conditions of the large-span steel structure roof. Through external data file drivers, they modify the structural parameters of the large-span steel structure roof and generate corresponding instances.

[0089] The fifth step involves the construction workers assembling the components in a unified manner to create a complete BIM model of the large-span steel structure roof.

[0090] Furthermore, in the above technical solution, the specific steps taken by construction personnel to adjust the elements in the new BIM model to adapt to the actual construction location during the creation of the new BIM model include:

[0091] The first step is for construction workers to determine the type and extent of deformation in the large-span steel structure roof;

[0092] The second step involves the construction team determining and adjusting the element parameters in the new BIM model.

[0093] The third step involves the construction team adjusting the curvature of the large-span steel structure roof by using curvature sliders and setting smoothing parameters during the creation of the new BIM model, adapting it to the actual construction location.

[0094] Furthermore, in the above technical solution, the specific steps by which construction personnel adjust the construction plan based on the simulation results to reduce structural deformation include:

[0095] The first step is for the construction team to build a model based on finite element analysis, define the construction stages, and select load combinations for each part of the large-span steel structure roof to conduct stress analysis on structures with different curvatures and their combinations.

[0096] The second step involves the construction team establishing important node models of the large-span steel structure roof based on the optimized BIM model and finite element model, and comparing the stress performance and failure modes of the nodes on their respective platforms.

[0097] The third step involves the construction team using BIM model technology to calculate the weight of the components of the large-span steel structure roof, selecting the installation method, and analyzing the stress state of the components in each scheme based on finite element analysis.

[0098] The fourth step involves construction personnel creating dynamic construction simulations of various schemes based on the BIM model of the large-span steel structure roof.

[0099] The fifth step involves the construction team integrating all stress data from each scheme with dynamic construction simulations to select the appropriate construction scheme.

[0100] Furthermore, in the above technical solution, the specific steps for fixing the structural foundation of the large-span steel structure roof based on the optimized BIM model of the large-span steel structure roof include:

[0101] The first step is for the construction personnel to analyze the stress points of the large-span steel structure roof based on the optimized BIM model of the large-span steel structure roof.

[0102] The second step involves the construction workers selecting five points from the stress points as the main stress points and setting the rest as auxiliary stress points.

[0103] The third step is for construction workers to fix the support columns at the corresponding positions of the main stress points;

[0104] The fourth step involves the construction workers fixing the steel structural components at the corresponding positions of the auxiliary stress points. The supporting columns and steel structural components together form the structural foundation of the large-span steel structure roof.

[0105] Furthermore, in the above technical solution, the specific steps for construction personnel to analyze the stress points of the large-span steel structure roof based on the optimized BIM model include:

[0106] The first step is for construction workers to import the BIM model of the large-span steel structure roof into Graphisoft Archicad software for stress analysis.

[0107] The second step involves the construction workers adding various loads to the large-span steel structure roof and adjusting the load parameters.

[0108] The third step involves the construction team performing calculations and analyses on the BIM model of the large-span steel structure roof based on Graphisoft Archicad software under load conditions to obtain the stress points of the large-span steel structure roof.

[0109] Furthermore, in the above technical solution, the specific steps for construction personnel to select 5 points as primary stress points and the rest as secondary stress points include:

[0110] Based on the environment of the actual construction location of the large-span steel structure roof, the construction personnel selected 5 points as the main stress points. There were no obstacles at the main stress points in the actual construction location of the large-span steel structure roof, and the remaining stress points were set as auxiliary stress points.

[0111] Furthermore, in the above technical solution, the specific steps for installing the prefabricated steel structure on the structural foundation of the large-span steel structure roof and for securely connecting the steel structure to the structural foundation include:

[0112] The first step is to determine the location and dimensions of the steel structure, and then position and adjust it according to the location of the structural foundation;

[0113] The second step is to inspect the surface of the steel structure to ensure it is free of defects and scratches;

[0114] The third step is to install the steel structure base and fix the steel structure to the structural foundation.

[0115] The fourth step is to install the steel structure frame and fasten it to the structural foundation of the steel structure roof with bolts.

[0116] The fifth step is to install the steel structure beams, connecting them to the steel structure frame and securing them with bolts.

[0117] Step 6: Install the steel structure panels. Install the structure panels onto the steel structure beams and secure them with bolts.

[0118] Step 7: Install the steel structure space frame, connect the space frame to the steel structure roof, and securely connect the steel structure to the structural foundation.

[0119] Furthermore, in the above technical solution, the insulation layer includes three layers: a fiberglass layer, an extruded polystyrene board layer, and an insulation coating layer. The fiberglass layer is fixedly connected to the steel structure by rivets. The extruded polystyrene board layer is placed between the fiberglass layer and the insulation coating layer and is fixedly connected by adhesive. The insulation coating layer is placed on the side of the extruded polystyrene board layer away from the fiberglass layer.

[0120] The adhesive components include: 25-30 parts polyacrylamide, 15-22 parts sodium silicate, 5-8 parts filler, 6-8 parts additives, 3-6 parts heat-insulating agent, 2.5-4 parts surfactant, 23-28 parts acetone, and 40-45 parts water.

[0121] The additives are a mixture of sodium chromate, nonylphenol polyoxyethylene ether, and p-toluenesulfonic acid, with a weight ratio of sodium chromate:nonylphenol polyoxyethylene ether:p-toluenesulfonic acid of 1:5-7:3.5-5.

[0122] Furthermore, in the above technical solution, the thermal insulation coating layer is one of microporous polystyrene, expanded perlite, and organic polymer composite thermal insulation materials.

[0123] Specifically, the principle of this invention is as follows: Construction personnel construct a BIM model of the large-span steel structure roof according to the design drawings; the BIM model of the large-span steel structure roof is optimized based on the actual construction location of the roof to ensure that structural deformation is minimized during construction; the structural foundation of the large-span steel structure roof is fixed based on the optimized BIM model; the prefabricated steel structure is installed on the foundation, and the steel structure is securely connected to the foundation; an insulation layer is laid on the surface of the steel structure to reduce heat reflection and improve the insulation performance; a waterproof layer is laid on the insulation layer to prevent moisture from penetrating the roof and improve its waterproof performance; asphalt concrete is laid on top of the waterproof layer as the surface layer to improve the roof's wear resistance, waterproofness, and wind resistance; after the construction of the large-span steel structure roof is completed, structural inspection and reinforcement are carried out to ensure the stability and safety of the roof structure.

Claims

1. A method for reverse construction of a large-span steel structure roof, characterized in that, The method comprises the following steps: S10: a construction worker constructs a BIM model of a large-span steel structure roof according to design drawings; S20: the construction worker optimizes the BIM model of the large-span steel structure roof according to an actual construction position of the large-span steel structure roof, so as to ensure that structural deformation is minimized during construction; S30: a structural foundation of the large-span steel structure roof is fixed according to the optimized BIM model of the large-span steel structure roof; S40: a prefabricated steel structure is installed on the structural foundation of the large-span steel structure roof, and the steel structure is tightly connected with the structural foundation; S50: an insulation layer is laid on a surface of the steel structure, so as to reduce thermal reflection of the steel structure and improve the insulation performance of the large-span steel structure roof; S60: a waterproof layer is laid on the insulation layer, so as to avoid water from penetrating into a house and improve the waterproof performance of the large-span steel structure roof; S70: asphalt concrete is laid on the waterproof layer as a surface layer of the large-span steel structure roof, so as to improve the wear resistance, waterproofness and wind resistance of the large-span steel structure roof; S80: after the construction of the large-span steel structure roof is completed, structural inspection and reinforcement work are performed, so as to ensure the stability and safety of the roof structure; The specific steps of S30 comprise: Firstly, the construction worker analyzes stress points of the large-span steel structure roof according to the optimized BIM model of the large-span steel structure roof; Secondly, the construction worker selects five points as main stress points from the stress points, and sets the rest as auxiliary stress points; Thirdly, the construction worker fixes support columns at positions corresponding to the main stress points; Fourthly, the construction worker fixes steel structure components at positions corresponding to the auxiliary stress points, and the support columns and the steel structure components constitute the structural foundation of the large-span steel structure roof; The specific steps of the first step of S30 comprise: (1) the construction worker enters Graphisoft Archicad software to import the BIM model of the large-span steel structure roof to perform stress analysis; (2) the construction worker adds various loads on the large-span steel structure roof and adjusts parameters of the loads; (3) the construction worker performs calculation and analysis on the BIM model of the large-span steel structure roof under load bearing based on the Graphisoft Archicad software, so as to obtain the stress points of the large-span steel structure roof.

2. The reverse construction method of a large-span steel structure roof according to claim 1, characterized in that, The specific steps of S20 comprise: Firstly, the construction worker obtains detailed information of an actual construction position, including ground coordinates, building position and surrounding environment; Secondly, the construction worker analyzes the BIM model of the large-span steel structure roof to determine an adjustment part of a shape, size and position of the roof; Thirdly, the construction worker creates a new BIM model based on the BIM model of the large-span steel structure roof and the adjustment part of the shape, size and position of the roof; Fourthly, the construction worker adjusts elements in the new BIM model during creation of the new BIM model to adapt to the actual construction position; In the fifth step, the construction personnel simulates the construction process using the optimized BIM model of the large-span steel structure roof. In the sixth step, the construction personnel adjusts the construction scheme based on the simulation results to reduce the structural deformation.

3. The reverse construction method of a large-span steel structure roof according to claim 2, characterized in that, The fourth step of the S20 includes the following specific steps: (1) The construction personnel determines the type and degree of deformation of the large-span steel structure roof. (2) The construction personnel determines the adjustment of the element parameters in the new BIM model. (3) The construction personnel adjusts the curvature of the large-span steel structure roof by adjusting the curvature slider and setting the smoothing parameter during the creation of the new BIM model.

4. The reverse construction method of a large-span steel structure roof according to claim 3, characterized in that, The sixth step of the S20 includes the following specific steps: (1) The construction personnel defines the construction stage based on the finite element analysis model, selects the load combination for each part of the large-span steel structure roof, and performs stress analysis on different curvature structures and their combinations. (2) The construction personnel establishes the important node model of the large-span steel structure roof based on the optimized BIM model and finite element analysis, and compares the stress performance and failure mode of each platform. (3) The construction personnel calculates the weight of the component structure of the large-span steel structure roof based on the BIM model technology, selects the installation method, and analyzes the stress state of each scheme based on finite element analysis. (4) The construction personnel creates a dynamic construction simulation based on the BIM model of the large-span steel structure roof. (5) The construction personnel selects the construction scheme by integrating all the data and dynamic construction simulation of each scheme.

5. The reverse construction method of a large-span steel structure roof according to claim 4, characterized in that, The specific steps of the S40 include: First step, determine the location and size of the steel structure, and position and adjust according to the location of the structure foundation; Second step, check the surface of the steel structure to ensure no defects and scratches; Third step, install the steel structure base and fix it on the structure foundation; Fourth step, install the steel structure frame and fasten it to the structure foundation of the steel structure roof with bolts; Fifth step, install the steel structure beam and connect it to the steel structure frame using bolts; Sixth step, install the steel structure plate on the steel structure beam and fasten it with bolts; Seventh step, install the steel structure net rack and connect it to the steel structure roof, and fasten the steel structure to the structure foundation.

6. The reverse construction method of a large-span steel structure roof according to claim 5, characterized in that, The thermal insulation layer includes three layers: a glass fiber layer, an extruded polystyrene board layer, and a thermal insulation coating layer. The glass fiber layer is fixedly connected to the steel structure through rivets. The extruded polystyrene board layer is arranged between the glass fiber layer and the thermal insulation coating layer and is fixedly connected through an adhesive. The thermal insulation coating layer is arranged on the side of the extruded polystyrene board layer away from the glass fiber layer.

7. The reverse construction method of a large-span steel structure roof according to claim 6, characterized in that, The thermal insulation coating layer is one of microporous polyphenyl, expanded perlite, and organic polymer composite thermal insulation material.

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