The installation of the steel structure of the LED display screen is a relatively complex and comprehensive technology, with many contents and a wide range. Combined with some steel structure projects, the basic principles and applicable conditions of steel structure hoisting scheme design are expounded, and the feasibility of conventional installation methods and corresponding technical measures are summarized.

With the continuous development of science and technology, the shape and structural form of steel structures are becoming more and more complex, which brings new challenges to the design and construction of steel structures. For example, the Olympic venues represented by "Bird's Nest" and "Water Cube", as well as influential steel structure projects such as the National Centre for the Performing Arts, the new CCTV site, the Guangzhou TV Tower, and the Famen Temple Stupa, are not only innovative and developed in design. At the same time, new achievements have been made in steel structure installation technology. Many mature and advanced process methods have gradually become construction methods, which have played a role in promoting the development of the steel structure industry.

Due to market reasons, steel structure installation accidents and violations occur from time to time, resulting in unnecessary economic losses and social impacts. In order to further improve the overall level of steel structure construction and promote the development of the industry, in addition to strengthening construction site management, steel structure construction should also conduct research and summary in terms of construction organization design, program technical measures, etc.; vigorously promote new technologies and new processes; , Choose an advanced, reliable and economical construction scheme.

1. Basic principles of LED display steel structure hoisting scheme

1. Policy: Based on drawings and norms, strictly implement relevant national safety production regulations.

2. Reliability: Adhere to safety first, ensure the feasibility of the implementation of the plan, and increase its reliability. No matter which method is adopted, the first thing to consider is whether the scheme has a successful precedent and supporting equipment, otherwise, a scheme demonstration must be carried out. According to the structural characteristics, the construction check calculation is carried out to prove whether the stability of the structure, the stress and deformation of the rods and so on in the construction stage of the method meet the requirements. Whether the mechanical equipment used can meet the installation requirements. Whether the construction site conditions are met, such as whether the civil construction environment and surrounding structures restrict the implementation of the plan, etc.

3. Advancement: With the development of science and technology, new processes, new technologies and new equipment in the field of structural installation are emerging one after another. For example, the advent of large-tonnage cranes and the computer synchronous control of the overall lifting and sliding technology have added a new chapter to the structural installation. Especially for large-scale steel structure projects, when the site conditions and structural form allow, the application of new technologies and new processes should be vigorously promoted; the amount of aerial work should be minimized and the installation efficiency of steel structures should be continuously improved.

4. Economical: A good installation plan should be simple in method, appropriate in measures, high in efficiency, low in construction cost, wide in application, and stand up to review and test. Therefore, we must adhere to the principle of scheme comparison, carry out technical and economic analysis, and choose a scheme with a short construction period and low cost.

2. The applicable conditions of the LED display steel structure hoisting scheme

Due to the inconsistency of architectural shapes and structural forms, the construction site conditions vary widely. It can be said that no construction method or scheme is suitable for the installation of any steel structure project, so each installation method has its own supporting conditions.

Commonly used installation methods for grid structure include: high-altitude bulk method, strip and block installation method, structural slip method, support frame slip method, integral hoisting method, integral lifting method, etc.

1. Consider according to the process method: understand the characteristics of the structure form, structure weight, installation height, span, etc., and try to choose a mature and advanced installation process in combination with the actual situation on site.

2. Considering according to the lifting equipment: first, choose your own equipment, make full use of the lifting equipment on site, and then rent it nearby. General situation: when the number of components is small, truck cranes are mostly used; small and medium-sized truck cranes are mostly used for gantry rigid frame hoisting; when the installation period is long, the installation height and the turning radius are large, crawler cranes are more economical than truck cranes; overall Hydraulic synchronous hoisting (jacking) devices are mostly used for hoisting and sliding; tower cranes are generally used for the installation of medium and high-rise steel structures; gantry cranes and bridge erecting machines are mostly used for ordinary bridge installations.

3. Flip-chip method construction: The flip-chip method is a special installation process that is first up and then down. It is suitable for structures with large height-to-width ratios, such as steel towers, masts and other structures. When conventional cranes are difficult to hoist close to each other, the flip-up method is generally used. When adopting this method, it is necessary to focus on the overall stability of the structure and the stability of the equipment itself during the installation process, and there must be reliable support and stabilization measures. Structural slip method - The structural slip method has been developed to use hydraulic jacks and computer synchronous control technology, which is a step further than the past grid slip method. Its applicable conditions are: first, due to site conditions, cranes and support frames cannot be installed in the span; second, the structural support conditions are conducive to laying the slip track; third, the strength and The stiffness all meet the requirements; fourth, understand the form and fixing method of the structural support; fifth, the longer the longitudinal slip route, the higher the efficiency. Support frame sliding method - its applicable conditions are that it occupies the site within the span, the installation height is low, the structural area is large, or the longitudinal length is long. First, when the installation height is below 15 meters, ordinary fastener-type steel pipe scaffolding or bowl-mouth scaffolding can be used as the support frame; second, when the frame body is high and the bearing capacity is large, the steel support frame should be used. No matter which scheme is adopted, in addition to the requirements of the specification, the horizontal dynamic load should also be considered in the design calculation, and if necessary, large diagonal braces should be added to improve the overall stability.

4. Overall lifting method: At present, the overall lifting method mostly adopts computer synchronous control and hydraulic lifting equipment developed by Tongji University. This process gradually replaces the through-center motorized lifting and jack lifting schemes. The equipment is light and the technology is advanced. Its applicable conditions are: first, occupy the site within the span; second, the installation height is higher; third, the components are heavier; fourth, it is limited to vertical hoisting and cannot be displaced horizontally. That is, the higher the installation height, the heavier the lifting weight, the better the effect.

5. Earth method hoisting: Earth method hoisting is the use of single-angle bar, herringbone frame, rolling machine, pulley block, etc. as lifting equipment for structural hoisting. It is suitable for projects with heavy components, small number and high installation height. Due to the increasing number of large-tonnage lifting equipment and advanced installation techniques, there are fewer and fewer local hoisting.

6. Rotation method construction: This method is mainly used for bridge installation. Due to the influence of railways, highways, and special environments such as mountains and rivers, when other bridge construction methods are limited, the rotation method is mostly used for construction.

7. Overall lifting method: It is basically similar to the overall lifting method, but the lifting equipment is different, and it is suitable for small and medium-sized structure installation. In the early days, multiple monopods or herringbone frames, winches, pulleys and cable wind systems were used for large-tonnage hoisting. Now, due to the large number of large-tonnage cranes, multiple cranes are selected for centralized lifting and installation for small and medium-sized projects as needed.