There is really no unified standard for judging the structure of heavy steel and light steel structure, and many experienced designers or project managers often cannot fully explain it, but we can comprehensively consider and judge based on some data: Heavy steel structure 1. Lifting weight of the workshop truss: ≥25 tons. 2. Steel consumption per square meter: ≥50KG/㎡. Light steel structure refers to the light steel structure made of round steel and angle steel smaller than L45×4 and L56×36×4. There is no mention of heavy steel in national specifications and technical documents. "Code for Design of Steel Structure" GBJ17-88 has been abolished since December 1, 2003, and the "Code for Design of Steel Structure" GB50017-2003 is currently implemented
As a consensus, compared with the currently commonly used concrete, the steel structure can be constructed in a dry manner, saves water, occupies less land for construction, generates less noise and dust; 3. The use of concrete and bricks and tiles has been greatly reduced, and the excavation of rocks around the city has been reduced, which is beneficial to environmental protection. Less garbage, high recycling price of scrap steel resources. From the current point of view, steel structure buildings are one of the structures that have the least impact on the urban environment, and have been widely used in the West, so they are called green buildings. my country has also formulated a series of technical specifications and supporting policies and organizations for the development of steel structures: 1. In 1996, the Ministry of Construction compiled the "1996-2010 Construction Technology Policy", which proposed to develop anti-corrosion technology, waterproof and fire-resistant coating technology for steel structures. In order to meet the development needs of construction steel; 2. In October 1998, the Ministry of Construction issued the "Notice on the Promotion and Application of 10 New Technologies in the Construction Industry", in which the 8th new technology to be promoted is steel structure technology. The main contents are: high-rise steel structure technology, space steel structure technology, steel-concrete composite structure technology, high-strength bolt connection and welding technology, steel structure protection technology; 3. In May 1999, the Ministry of Construction and the State Bureau of Metallurgical Industry were established. Construction steel technical coordination group, and established two expert groups, "reinforced concrete" and "steel structure"; At the Structural Technology Development Seminar, the Ministry of Construction and the State Bureau of Metallurgical Industry formed a national steel structure expert group to discuss the "Tenth Five-Year" plan for the national construction steel structure industry, the outline of the 2010 development plan and the construction steel structure engineering technology policy. Experts propose that building steel structures be classified into five categories: high-rise heavy-duty steel structures, large-span steel structures, light-duty steel structures, steel-concrete composite structures, and residential steel structures. During the "Tenth Five-Year Plan" period, residential steel structures should be the focus of development. 5. The Ministry of Construction Jianbiao (2001) No. 131 document promulgated the national industry standard of frequency welded thin-wall H-beam for structural use. This move will promote the further promotion and application of domestic high-frequency welded H-beams. Under the guidance of these policies, my country's steel structure buildings have developed rapidly. Since the 1980s, more than 40 high-rise steel structure buildings have been built or under construction in mainland my country, with a total area of about 3.2 million square meters, a steel consumption of about 300,000 tons, and a capital of about 60 billion yuan. In Beijing, Shanghai, Shenzhen, Dalian, Tianjin and other places, a construction boom has formed, especially in Lujiazui Financial District in Pudong, Shanghai. There are 12 high-rise steel structure buildings that have been completed or are under construction. The completed Shanghai Jinmao Building (88 floors, high up to 420.5 meters) and the World Financial Tower under construction, making China's high-rise buildings into the forefront of the world. Correspondingly, great progress has been made in the scientific research, design and various supporting construction of high-rise steel structures. The mechanized construction companies of the system have reached a high level in the production and installation of steel structures. In recent years, the spatial structure represented by the grid and the grid shell has also continued to develop in a large amount. The structure is characterized by reasonable force, high rigidity, light weight, single rod, easy production and installation, and can meet the requirements of large span, high space and various architectural forms. It is not only used in general civil buildings, but also in industrial plants, hangars, terminal buildings, stadiums, exhibition centers, etc. Such as Tianjin Seamless Steel Tube Factory, Capital Airport Maintenance Depot, Tianjin Gymnasium and Shanghai Gymnasium all have a span of 70 to 80 meters. The dry welding shed of Yangzhou No. 2 Power Plant has already adopted several grids or grid shells with a span of more than 100 meters. In contrast, Yunnan Yuxi Cigarette Factory's continuous grid-frame workshop has reached 120,000 square meters, and the spatial grid structure is rich in shape changes, such as the butterfly-shaped reticulated shell of Yichun Stadium, the shell-shaped reticulated shell of Weihai Gymnasium, and the multi-d
1. From the design structure point of view: ①European crane: the main girder adopts the box girder structure, which has a reasonable structure and higher strength. Effective working space, the largest clearance difference, up to 1.5 meters, the wheel pressure is reduced, and the rail-bearing beam is reduced; ② Traditional crane: limited by the hoist design, only the traditional I-beam structure can be used, the structure is unreasonable and the utilization rate The combination of the hoist and the lower flange of the main girder leads to a high incidence of breakaway accidents. 2. From the appearance: ①European crane: The appearance is light and beautiful, in line with modern industrial aesthetics, effectively using the workshop space, the limit distance between the hook and the walls on both sides is small, the headroom is low, and the layout planning of the existing workshop is more Flexible, the new workshop can be designed to be smaller and have more complete functions; ②Traditional crane: the appearance is thick, heavy, the limit size in vertical and horizontal directions is large, and the effective working area is small. Under the same workshop structure, the space utilization rate is low. . 3. In terms of volume: ①European crane: the lowest headroom, the smallest self-weight, good wind resistance, good running balance, safe and reliable; ②traditional crane: large amount of steel, relatively large volume, large impact, and shaking of the load severe. 4. From the installation design point of view: ①European crane: fully enclosed design, not attached to dust, frequency conversion speed regulation, safer to use; ②Traditional crane: The structure of the reduction box is open, exposed to the air, and easy to attach to dust. 5. From the perspective of operation and maintenance costs: ①European crane: the whole machine has low power, low power consumption, reliable quality, and low failure rate during correct use, which can minimize the loss caused by equipment failure and production. It also saves equipment maintenance costs; ②traditional cranes: the power of the whole machine is large, the operation cost is high and the power consumption is high. The parts have a short life span and a high failure rate due to cost constraints during the use of the crane. cost.
With the continuous development of modern society and economy, the quality of people's living quality has been continuously improved, and the living environment, living conditions and living needs of human beings are also constantly changing. In the country, the control of the land use system is becoming more and more strict. is getting thinner. Buildings are increasingly developing towards super high-rise buildings, and reinforced concrete structures can no longer meet the needs of building benefits, building structures, construction design and some special functional requirements. Steel structures are widely used in high-rise buildings because of their light weight, high strength, good plasticity and toughness, easy fabrication and short construction period.
1. Introduction: Since steel structure engineering is generally used as the core part and stressed structure of high-rise buildings, its quality directly affects the safety, structure and durability of the building. Cause huge economic losses and heavy casualties. Therefore, the construction steel structure project is listed as a special project, and the national and local construction departments attach great importance to the quality of the steel structure project, and accordingly formulate and promulgate a variety of specifications, standards and technical regulations including and sub-projects. Many experts in the industry have devoted themselves to research in this area for many years, and have written a large number of monographs and documents from different perspectives, making great contributions to steel structure engineering from design to construction, from new technology to the application of new technologies.
The development of the construction industry in recent years is also obvious to all. Architectural engineering is not only a place to meet people's work, life and living functions, but also a highlight of urban construction and a landscape of the city. The main trend of development and city business card. With the increasing popularity of high-rise buildings, steel structure engineering is increasingly taking advantage of its advantages of fast construction speed, short period, saving formwork, high strength, fast construction, and easy prefabrication installation, so it is more and more widely used in engineering. In this regard, the state has compiled the "Code for Construction Quality and Acceptance of Steel Structures" and "Welding Regulations for Steel Structures" according to the construction characteristics of building steel structures. At the same time, experts and scholars in some industries have also compiled relevant steel structure-related industries and corporate standards. For example, China State Construction Engineering Corporation has compiled "Steel Structure Processing Technology", etc. Although various standards and regulations have been issued and operated, there are often some steel structure projects that have problems of one kind or another, such as cracks in steel structure projects, components Surface paint peeling off and other similar quality problems, although very few of them involve raw materials, because once raw materials have problems, it will directly affect the safe use of buildings. Most of them are engineering quality problems caused by production, processing and construction and installation problems. To eliminate the common quality problems of steel structure engineering is a huge systematic project, and it is necessary to pay enough attention to each stage of the construction process, all parties involved in the construction, and each process and link of the design and construction. At the same time, the promotion and application of new technologies and processes of steel structures should also increase publicity efforts, so that everyone can truly feel the importance of the steel structure engineering office to people's living, living and working relationships, and maximize the control of common quality problems. and be eliminated.
2. Analysis of quality problems in steel structure engineering There are many reasons for the difficulty in guaranteeing the quality of steel structure engineering, and they are very complicated. There are not only problems caused by improper process, but also problems caused by violation of process operation. The problems caused by responsibility, and the quality problems caused by the mistakes of decision makers. This article mainly analyzes the problems that are most likely to occur in the production process of building steel structures. I hope everyone can get a little inspiration from it: (1) Problems in the steel itself When a unit is processing a 1200*1200*60 box-shaped column in a building , During the welding process, it was suddenly found that the 60mm thick plate as the web had a tearing phenomenon. The clear cracks were visible to the naked eye and divided the plate into two halves from the thickness direction. After NDT inspection, it was found tha