Before the 1980s, general industrial plants were treated with concrete structure, small span roof truss is a concrete, large span roof truss used steel truss type roof, but using brick & concrete slab. After the 90 "s of the 20th century, with the development of computer technology, grid structure stand out, covering almost the all large-span industrial plant, but the roof is concrete grid plate that is heavy load, the economy is poor. 95 years later, with gabled frame structure system development and color steel tile technology is mature, portal rigid frame almost was a monopoly of the domestic industrial plant market. The people that leaded domestic steel structure workshop thought: Steel structure consists of 2 types: 1. Portal steel structure; the steel frame structure -- the pure frame and braced frames, eccentrically braced frames, framed tube (dense column frame); 2 grid structure, grid, shell; the cable membrane structure -- cable structure, membrane structure, of which the membrane structure and tension type, frame type and pneumatic membrane structure.
The door type rigid frame has some advantages, like high degree of industrialization, high construction speed, light weight, high strength and large span, high fire resistance, high corrosion resistance, good seismic performance, recycling of non polluting green. Portal frame includes civil foundation, steel columns, steel beams, wall purlin, purlin roof, walls color steel tile, roof color steel tile, gutter, doors, windows, ventilation equipment. Wall and roof panels often use sandwich insulation materials. But for some large span roof structure, space truss structure is unique; the industry practice is to selects the structural system mainly according to their functional requirements carefully.
Steel structure has the following advantages:
Most of the low storey villa roof is slope, so roof structure basically is triangular roof truss system that made of cold-formed steel pieces, after the completion of structural plate and plaster board in light steel structure, it will form a very strong "plate rib structure system”, it’s structure has a better anti-seismic level above 8 degrees.
2 Wind resistances
Steel structure is light weight, high strength, high rigidity, and good deformation ability. The weight of the steel building is only one fifth of the brick and concrete structure, hurricane resistance 70 metres per second, life and property can get effective protection.
Light steel structure housing is composed of the cold-formed and thin-walled steel system, steel is cold rolled galvanized steel sheet with super anticorrosion and high strength, effectively avoid corrosion of steel plate in the process of construction and use, and increasing the service life of steel. The life of steel structure is over 100 years.
The heat insulating material is mainly used as glass fiber cotton, and has good heat preservation and heat insulation effect. With the external wall thermal insulation board, effectively avoid the wall of the "cold bridge" phenomenon, to achieve a better thermal insulation effect. The thermal insulation about 100mm R15 thick cotton can be equivalent to that of 1m thick brick wall.
5 Sound insulation
Sound insulation effect is an important index for assessment of residence, windows for light steel system adopt a hollow glass, sound insulation effect is good, the noise is more than 40 db; the sound insulation of steel structure is composed of light steel keel, heat preservation material gypsum board wall, its sound insulation effect can be up to 60 dB.
The steel structure project can be operated dryly, this can reduce waste and environment pollution, the material of steel structure housing is 100% recyclable, other supporting material also is mostly recoverable ,currently, all materials for the green building is developing towards more environmental and healthier.
Light steel wall with a high efficiency energy saving system, and respiratory function, it can regulate indoor air humidity; roof with ventilation function can make an air flow that can produce ventilation and cooling.
All dry constructions will not effected by environment and season. A steel building project about300 square meters can be completed by only 5 workers in 30 working days from foundation to decoration.
Steel structures adopt efficient energy-saving material such as, wall, heat insulation, sound insulation. They can reach 50% energy-saving standards