Light steel building projects the quality investigation drip to

Light steel building means: portal frame light steel structure housing, pressure plate sandwich panel light envelope structure, 1 to 3 layers of light steel residential, low-rise office light steel structure buildings and light combination of housing, etc. which the widest range of portal frame light steel structure housing applications, the largest amount. This article surveys the main content is about the quality of the project portal frame light steel structure housing situation.
A portal frame light steel building development overview:
A review of twenty years history of the development of steel buildings, light steel structure housing the main portal frame is one of the fastest growing and most widely used building new technologies and products.
Entry of foreign manufacturers, the introduction of new technologies and new products:
1) 1979 Shanghai Fisheries Road Lun library to introduce Japanese S60 pressure plate molding machine for plant Lun library roof, Shanghai Baosteel in 1980 a project to introduce Japan W550, V115N steel sheeting forming machine roof wall in a project surface nearly 600,000 square meters of building envelope applications, it is the first time in the early 1980s, the largest amount of engineering.
2) 1983 Economic Development Zone, Shekou Industrial Zone began deep training and the introduction of a large number of the United Kingdom, the United States, Australia and Japan, the door-frame light steel structure workshop Lun library. Introduction of Australia prestressed door lattice-type light steel structure Lun library. Coastal economic development zone then gradually introduce abroad light steel plant Lun library, this building can also be used for logistics Lun Chu, supermarkets, wholesale markets, farmers markets and other commercial buildings; for sports and drinking places Museum and Exhibition Center; used in office buildings and other multi-storey buildings.
3) 1994 U.S. companies invest in creating Upbest Steel Structure Co., Ltd., and the Jiading plant put into operation in 1996. Has over 500 large and medium-sized projects in the domestic construction, building area of ​​more than 580 million square meters.
Engineering Construction Co., Ltd. of the United States the Midland Steel Structure Co., Ltd. (USA) and the United States Hongyu built in China in 1994 dozens of product design, manufacturing technology and management software, all imported from the United States of America USA steel building systems, providing customers with provide housing design, production to install the perfect service.
PCC Steel, Shanghai Baosteel Group Investment Holdings in 1993, the Taiwan management into shares of the steel building company. The Baocheng Steel set to introduce the American Maple design systems, building products, systems and production lines, with a set of pre-engineered steel housing sales offer design, installation in one full set of services.
ASTRON building system is the best quality of the Luxembourg subsidiary in the United States in Europe, the maximum amount of light steel structure building system. ASTRON building system in 1994, China has built more than a dozen large projects in Beijing, Suzhou and other places.
Taiwan-owned enterprise in 1994, Hua Yin factory in Xiamen, factories in Kunshan, Jiangsu Province in 1996, has set up branches and offices in Beijing, Shanghai, Dongguan, Xi'an, Nanjing and other places.
Then manufacturers entering the country, the United States Belem Steel Structure Construction Co., Ltd.; Oddo, Singapore, Malaysia and Australia joint investment company of steel products; many manufacturers of Taiwan-funded enterprises in Hangzhou Xinfeng Steel Company.
4) The key new materials, new products and new technology:
Computer-aided design and production of the portal frame (1) (CAD-CAM), portal frame light steel structure housing design and construction procedures.
(2) z-type oblique curling cold-formed steel, C-type cold-formed thin-walled of section steel Eurya bar wall beam material, design calculations and tectonic the knee bracing settings and structure;
(3) the steel sheeting of the roof and wall material selection, design calculations and links structure; the board upright seam 360 degrees occlusion pressure plate type connections and other accessories, board and other accessories of the the chimeric pressure plate connections sandwich panel board and component connections, the manufacturers own roofing systems, wall systems.
2. Domestic portal frame light steel structure housing development
1) 1980 Shanghai Baosteel Construction Headquarters was established thematic group pressed aluminum steel sheeting Experimental Study digestion and absorption of a project to introduce Japanese color coated steel sheeting and molding equipment, test use of domestic aluminum alloy plate instead of color coated layer steel plate made pressure plate for roof and wall building envelope, after an investigation and extensive experimental research in Baosteel roof and wall of a project to promote application of more than 60 million square meters of aluminum alloy pressure plate, pressure plate and molding research and application of the production line, and the National Science and Technology Progress Award.
2) in 1984, the Building Research Institute of the Ministry of Metallurgical Industry researchers in learning the Baosteel and Shenzhen Shekou Industrial Zone pressure plate and gantry frame light steel structure on the basis of foreign advanced technology, combined with the specific situation of China research and development of portal frame light Steel plant Lun library, first used in the Business Department of the urgent need to build national cotton reserve Lun She, three years in the areas of Shandong and Henan three provinces over forty, construction of a light steel cotton Lun library of more than 300 buildings, construction area of ​​more than 200,000 square meters, the project won the National Science and Technology Progress Award. 1986 bear food infrastructure of the Department of Commerce in Nagqu Prefecture in Tibet national food reserves Lun library construction, praise of the Tibet Autonomous Region and the Ministry of Commerce.
3) Building Research Institute of the Ministry of Metallurgical Industry is one of the earliest research and development of light steel structure housing units, a compound of a group of researchers lightweight welded H-shaped steel, cold-formed steel, the mechanical properties of the steel sheeting, processing technology and its processing equipment, other accessories fittings and sealing materials research and development, engineering design and application of light steel building, presided over or participated in the preparation of national standards and regulations and standards.
4) With the deepening of reform and opening up, China's rapid economic growth, the portal frame light steel structure housing industry has been rapid development, especially in the southeast coastal areas, new plants Lun library growth in demand prompted manufacturers of light steel structure housing processing installation mushroomed developed from the beginning of the development of small-scale modern enterprise Hangxiao Steel Seiko Zhejiang Hengda Steel, Shanghai GM, Wu Tai Steel, four new Steel, Baosteel color plates, northern space Steel enterprises are professional the Beijing Foton Steel, Beijing multidimensional Steel, Chengdu Huiyuan, Sichuan Hengsheng portal frame light steel structure manufacturer, annual sales are in the hundreds of millions, more than ten billion yuan. The national manufacturers engaged in the manufacture of light steel structure of the portal frame is estimated that about 500, more than 50 of a certain scale. Portal frame light steel structure fabrication and installation of quality housing also gradually improve, more and more beautiful novel architectural modeling, such as Cambridge and Pu Industrial Park of Shanghai GM plant, Butler contractor Motorola Tianjin, Shanghai and the United States built construction Tianjin Development Zone, the mint plant and a new machine tool plant in Beijing, Hunan six built construction Changsha Bosch plant and so are the industry quality engineering.
5) pressed steel sandwich panel processing manufacturers across the country, some manufacturers already own roof and wall containment system, some manufacturers to introduce advanced foreign equipment and technology has improved continuously. Dozens of domestic pressure plate board type, and most of its production lines are manufactured domestically. Introduction of sandwich panel production line manufacturers, according to incomplete statistics, there are more than 20 production lines, mainly imported from Italy, Germany, South Korea, Australia and other countries. At present, the domestic manufacturers can produce sandwich panel production line.
6) portal frame light steel structure housing a large number of applications, driven by the development and prosperity of the design software development of the related industries, the manufacturing of welded steel, cold-formed steel pressure plate processing equipment, lighting tile also many other accessories connected pieces and sealing materials manufacturer and agent technology level gradually improved.
7) on the design and construction standards and regulations and of the preparation of the Atlas:
(1) Ministry of Metallurgical Industry Standards pressed sheet metal design and construction procedures "YBJ216-88, the Metallurgy Building Research Institute of the Ministry of Industry editor, is now being revised.
(2) China Engineering Construction Standardization Association standard portal frame light housing steel structure technical regulations CECS102: 98, Steel Structure Committee of China Construction Metal Structure Association, China Building Standard Design & Research Institute editor. The 2002 revision of the gantry frame light house steel structure the technical regulations CECS102: 2002. The gantry frame light house steel components JG144-2002.
(3) the national standard of the People's Republic of China "cold-formed steel structure technical specifications" GB50018-2002 "Steel Structure Engineering Construction Quality Acceptance" GB50205 - 2002 has a rigid frame, Eurya bar and wall beams, steel sheeting special section.
(4) New standard atlas have: the gantry frame light house steel structure (no crane) "Atlas No. 02SG518-1 gantry frame light house steel structure (crane)," Atlas No. 04SG518- 3, the pressure plate, sandwich panel roof and wall building construction "01J925-1, 06J925-2.
In summary it can be seen, the portal frame light steel building is one of the most promising building structure type and products, according to the statistics, in 2004 the gantry frame light house and the color coating steel sheeting steel accounted for 35.8% of the total amount of steel in the steel building, its construction area accounts for more than 80% of the total area of ​​the steel building. 2006 the young steel structure manufacturers Butler sales of 17 billion yuan, the construction area of ​​3.8 million square meters; the northern space sales of 1.235 billion yuan, the construction area of ​​3.25 million square meters. The fittings manufacturers Zhe Jiang Zhencheng sales reached 400 million yuan, self-tapping screws to buy 3 billion. The gantry frame light house in all walks of various types of plant and warehouses, supermarkets and wholesale markets store buildings, office and school buildings, a small stadium training hall gym, exhibition halls displaying very wide range of applications.

Portal frame light steel building problems:
Portal frame light steel structure housing each year the number of millions of square meters of the increase, but should see us there are still many technical and managerial aspects of the design calculations, building construction, manufacture, installation quality and after-sales service issues, differences between enterprises is relatively large, the overall level of foreign advanced technology gap, the portal frame light steel structure housing project quality overall is good, but due to the fast development of the industry, some of the technical regulations and management measures not sound, light steel construction market is chaotic, weak individual manufacturers quality awareness, lack of responsibility, the long-term goal of quality first, safety in production only in slogans, chaotic management, illegal subcontracting layers of subcontractors to cut corners in order to the times charged lower prices, this vicious competition will inevitably lead to the decline in the quality of the project, seriously affecting the reputation and development of the industry.
1) quality problems reflected in the housing use functional defects: the main problems found in the portal frame light steel structure houses completed and put into use following the impact of these problems, large will discontinued. :
(1) Roof leaks: because most of the roof the double steel sheeting and insulation glass wool composite is not easy to find the exact point of leakage, often also drain repair. Roof slab the condensation dripping impact production.
(2) wall windows up and down the eaves, door, awning extended parts sealed well water;
(3) plant poor quality of the installation and stiffness pulled crane plant shaking, the some plant the card rails phenomenon crane start inflexible;
(4) plant by strong winds or typhoon toppled or partial damage to the plant was overwhelmed by the blizzard or partially damaged;
2) design management and design quality problems:
(1) has a light steel special design qualification, but the technology backbone in place or the technical level is not high, bear outside the the design qualification level design; lightweight steel special design qualification everywhere affiliated; strict plan approval requirements; industry professional and technical personnel to be trained to improve the overall level of light steel special design qualification should be strict examination and approval, to strengthen management. Steel manufacturers design their own construction but also to the strict quality management to prevent jerry-building design and construction.
(2) In order to meet the requirements of the low price of the contract, the technical staff in without trial research is based on case excessive "optimize" the amount of steel portal frame, roof slope more and more flat the the steel sheeting wave more election The smaller the plate thickness is thin, the result of doing the door-frame light steel building carrying capacity reserve further reduced, could not resist the attacks of the strong winds and heavy snow.
(3) did not consider the special strengthening measures designed and constructed for the windy and snowy regions.
(4) The manufacturers of light steel special design qualification training of designers is not enough, designers studying learning lack not reference standard atlas design, structural design and building construction are evident at the unreasonable.
3) Steel Components manufacture and installation of the problems:
(1) the material selection of steel and steel plate thickness and design do not conform, most choose low intensity thin plate.
(2) Production of portal frame beams and columns H beam flanges and webs of steel plate flatness, welding quality steel components rust paint quality problems.
(3) did not follow the formal portal frame installation sequence for installation between the pillars supporting the roof support and brace no tension exists in name only some 10,000 square meters on engineering during installation, blown down by strong winds, causing a great loss.
(4) lap steel sheeting for roofing, roof openings at through the ethos floor at the pressure plate and lighting tile lap joints, waterproof construction imperfect measures, the construction is not causing roof leakage risks carefully. Some project Roofing self-tapping screws leakage hit, the impact of wind resistance. In addition, the roof profiled wall plate other parts processing installation accuracy directly affect the building's facade and beautiful, should also be given attention.
(5) do not pay attention to the civil construction of steel structure members, color coated steel sheeting pollute.
(6) steel columns independent foundation to the buried anchor bolts position is not accurate enough, the the basic top elevation error a direct impact on the accuracy of the installation of the pillars.
4) construction supervision or quality supervision station technical staff of the steel structure are not familiar with, it is difficult to find problems to solve the problem.
5) the responsibility of the owners and the credibility problem: Some gantry frame light house steel quality problems and the owners, for example, at the tender stage, the owners only consider the price (according to the strength of the manufacturers of several investigations lowest low bid in the price of 245 yuan / square meter, the most Gao 850 yuan / square meters), the price is too low forcing manufacturers to cut corners, According to the survey results, the portal frame light plant profit margin is only about 4.2%, if the final payment is received not back manufacturers would lose money. Tender required schedule too tight caused whirl progress rush period, some process is skilled work can not be sloppy, for example, encountered the Roof Engineering crashing will cause water leakage hidden; addition, manufacturers generally reflect the owners can not comply with the contract scheduled to pay for projects, especially the final payment is difficult to discuss back, as of 2006 less the prop owed 600 million, more prop arrears amounted to 50 million yuan, the problem is too serious, I hope to attract the leading departments to attach importance given to solve, the owners also talk about integrity.

Light steel structure construction industry healthy development proposals:
1) Looking to the future light steel building is a most promising building structure type and products, excellent performance for the continued development of light steel structure industry lay the foundation. Twenty-five years, the portal frame light steel structure house from scratch, from small to large, from simple to Gao file, unprecedented speed of development, popularization applied to other structural type of difficulty the degree of confidence in all parts of the country, Many manufacturers with annual sales of more than a billion, several large annual sales of more than ten billion. The next ten years, China's economic sustainable development and the revitalization of northeast, central China, the development of the western region gave light steel industry business opportunities, light steel building industry promising.
2) technological innovation is driving the sustainable development of light steel construction industry.
Portal frame light steel structure housing each year the number of millions of square meters of the increase, but should see us there are still many technical and managerial aspects of the design calculations, building construction, manufacture, installation quality and after-sales service issues, differences between enterprises is relatively large, the overall level of foreign advanced technology gap, qualified enterprises should set up special funds, professional staff for research and development of new products and technology, brand-name industry, engage in their own brand products so as to improve the competitiveness of enterprises in the market. For example: how to improve the capacity of portal frame light steel structure housing the wind resistance, anti-blizzard, how rich houses architectural modeling, and the creation of a unique building system, computer-aided design and manufacturing (CAD - CAM) research and development, H side welding of steel flange and web technology research is good research topic.
3) the quality and integrity is the key to the healthy development of light steel construction industry.
Portal frame light steel structure housing project quality overall is good, but due to the fast development of the industry, a number of technical regulations and management measures are not perfect, light steel construction market is chaotic, individual manufacturers cut corners, shoddy down prices, this vicious competition will inevitably lead to the decline in the quality of the project, and seriously affect the credibility of the industry and development. In order to ensure the quality of the project, the enterprise should be strictly design and construction management to formulate concrete steel structure of the company process, installation method and quality testing methods, in accordance with current national and industry standards and regulations, to develop the processing of pressed steel sandwich panel installation guide to ensure that each project are qualified, excellent, and establish a good business reputation. The industry as a whole will be a healthy development.

4) It is recommended often organized industry, new technologies and new product seminars, design and construction of key projects and large-scale projects and technological exchanges, engineering, accident analysis, scientific enterprise management experience exchange activities; give full play to the advantages of university research, expert advice, organizational research on key projects, design construction of a joint technical research; practitioners and technical personnel conduct regular training and examination requirements of the certificates; establish a system of inspection for the annual light design and production of special steel company owned post, strict management and inspection; carry light steel structure manufacturers with foreign technology engage in innovation cooperation and exchanges, broadens the mind. These measures will improve the technical level of the industry as a whole.
5) Experimental study on strengthening portal frame light steel structure, organized as soon as possible gantry frame light house steel structure technical regulations CECS102: 2002, pressed sheet metal design and construction procedures "the revision. The combined domestic experience in the use of light steel structure design and construction of the portal frame and appear revise and improve the procedures content, for example, our portal frame the housing carrying capacity reserves smaller than the United States; cross level of plant parapet , roof height difference at our snowy regions, strong winds, areas given special requirements. Two decades, the pace of development of the portal frame light steel structure, construction scale and penetration is unprecedented in the world and domestic, but due to the lack of research and development and technical training, impact of raising the level of the industry as a whole, about the door Frame Light steel structure, steel plate, cold-formed steel design and construction standards and regulations is urgent to modify and improve, and as a revision based on a lot of research needs to be conducted and the necessary pilot studies.