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Key Technologies and Measures for Steel Structure Construction of Super High - rise Buildings

1 Development of steel structure for super high - rise building

Super high-rise building is an important symbol of human conquest of nature and continuous progress, is the crystallization of the development of modern science and technology, but also a national science and technology development level and comprehensive strength of one of the concentrated expression. Therefore, both developed and developing countries have built high-rise buildings as an important means of demonstrating social development achievements. The super-high-rise buildings are usually used as a major component of steel structure, so super-high-rise buildings are generally super-high-rise steel structure. Modern high-rise buildings originated in the United States, has 110 years of development history, the construction of high-rise buildings not only has significant economic and social benefits, to show an era, a country's scientific and technological development achievements, and can greatly promote the relevant Field of science and technology development. So the rise of the current high-rise building construction of the new climax. Not only the height is getting higher and higher, such as up to 492m Shanghai World Financial Center, 508m Taipei International Financial Center, UAE more than 700m high Burj Dubai building (Burj Dubai), Figure l. And ultra-high-rise building style is also more diversified, to reverse the new TV Tower in Guangzhou and tilt the CCTV site construction project is one of the typical representative.

 

2. Features of modern large high-rise steel structure

Large-scale ultra-high-rise steel structure is usually high, heavy and other prominent features and common; and the last ten years, large-scale ultra-high steel structure and showing oblique, twisted, hanging and more specific characteristics. See Figure 2.1) High: Highly high risk of construction. 2) Weight: structural components, with a large amount of steel, high demand for mechanical equipment. 3) The twins, such as the Twin Towers of Puerta De Europa in Madrid, are the artificial Leaning Tower with a tilt of 15. Flat deformation. , The construction process will occur more water 4) twist: such as the new TV tower in Guangzhou, steel structure from the bottom up to reverse the 45. , The structure was three-dimensional tilt, the construction process not only positioning complex, but also by the temperature and other random load greater impact. 5) hanging: such as CCTV new site, high altitude cantilever pick out, making the structure hoisting and deformation control is very complex and difficult.

 

Large-scale ultra-high-rise steel structure construction of key technologies and measures to determine the large-scale high-rise steel structure construction technology route, the first of the construction of the object should be fully understood, and comprehensive technical, economic and environmental factors to consider. The understanding of the structure itself and the full understanding of the environment and its own resources are the prerequisites for determining the overall technical route of construction. The best technical route must be in line with the subjective and objective conditions, and make full use of time, space and its own expertise in the technical line. The main considerations are: 1) to understand the basic structure of the structure and load transmission path. Only by analyzing the basic composition of the structure can we properly divide the lifting unit. Only by analyzing the path of the structural load transfer can we determine the reasonable construction sequence and ensure that the construction completion state is consistent with the design requirements. For the super high-rise steel structure, steel columns, steel beams, steel trusses are the usual components, but also the main object of structural analysis. 2) familiar with the construction site conditions and the surrounding environment is a reasonable choice of construction equipment, effective construction and planning and construction of one of the important prerequisites. Construction environment also includes the owners of the construction requirements (such as duration, etc.), off-site transport conditions and civil construction and equipment installation and other procedures on the steel structure of the constraints. Taking full advantage of the environmental and spatial conditions of the construction site to achieve continuous, efficient and rapid construction, is to determine the installation of technical routes one of the main considerations. 3) to understand the allocation of resources and technical capacity, which is to determine the installation of an important prerequisite for the program. The construction enterprises have their specific resources and environmental and technical expertise to determine the construction technology route should give full play to their strengths and advantages in order to achieve a multiplier effect. For large high-rise steel structure, the key construction techniques and measures are mainly the following aspects.

3.1 Mechanical equipment selection

According to the actual situation of the structure, the choice of reasonable hoisting machinery, steel structure is the most important work. At present, the tower crane is the main high-altitude steel structure lifting equipment. The crawler crane, gantry crane can be used as low-altitude hoisting and component transport of auxiliary machinery. At present, the rapid development of the hydraulic jack jack can be used for large components or components and even the overall structure of the lifting, translation and rotation in place. According to the actual situation and structure of the steel frame of Guangzhou New TV Tower, two sets of 1200tm M900D tower crane are used as the main lifting equipment, and the steel structure is hoisted and placed in place. 2 sets of M900D installed in the core tube on both sides of the north and south. In addition, taking into account the distribution of construction time and structure weight and M900D installation time, 100m below the lifting, the auxiliary to the two 300t crawler crane, constitute four operating lines, synchronous lifting, greatly improving the speed. See Figure 3.

3.2 Measurement technology

Equipped with well-equipped instruments, carefully set the measurement base and reference network, select the correct measurement method and numerical transmission route, is the basic elements of engineering measurement. Super high-level structure due to high, poor visibility and other factors, structural measurement is very difficult. At present, the more advanced method is to establish a double control network, the use of GPS positioning system to measure the baseline network measurement and design, and high-precision total station as an important means of component air three-dimensional coordinate positioning, see Figure 4.

3.3 Welding technology

Super high-rise steel structure of the majority of the use of strong welding connection, not only the amount of welding, and high quality requirements. At the same time as the structure of ultra-high, most of the welding operations need to be completed at high altitudes, security control is difficult, climate impact significantly. Therefore, according to the different characteristics of steel and site construction conditions, select a reasonable welding process, equipment and materials, attention to high-altitude welding operation conditions, training skilled welding technicians, the implementation of technical measures to prevent wind and rain, timely non-destructive testing , Is the key to the steel site welding operations. In addition, the welding program must also be from the guarantee of welding quality, improve welding efficiency, reduce welding deformation and other factors to consider. At present, the use of carbon dioxide gas protection semi-automatic welding-based, manual welding, the most commonly used welding process, welding not only need to consider the overall and section of the welding sequence, a welding node also need to use symmetrical distribution welding welding sequence Minimize the adverse effects of welding deformation.

 

 

 

Source: http://www.huawei-cutting.com