ATTEN: Manager Liu
ADD: Longhua Development Zone, Jing County, Hengshui City, Hebei Province
The floor of multi-storey light steel structure building must have enough bearing capacity, stiffness and integrity. At present, it is commonly used to lay profiled steel reinforced concrete slabs on steel beams, i.e. profiled steel composite slabs, which are connected by bolts between profiled steel plates and steel beams. In addition, the pre-stressed thin slab with concrete cast-in-place layer or general reinforced concrete floor can be used, at this time, the reliable connection between the floor and the steel beam should be ensured. When considering the combined effect of steel beam and floor, the bearing capacity and overall stability of the beam can be significantly improved, and the height of the beam can be effectively reduced. The connection between main girder and secondary girder is usually simple supported equal height connection, sometimes it is inequality connection. For example, when using profiled steel plate composite floor, in order to facilitate the laying of profiled steel plate, the top of main girder and secondary girder has differential profiled steel plate enjoyment. At the same time, it can also increase the envelope structure of multi-storey light steel structure building with net storey height in order to reduce the multi-storey light steel structure building. Self-weight, enclosure knots are mostly made of light materials. Exterior walls are mostly filled with lightweight materials, such as hollow aerated concrete, sometimes with composite walls composed of profiled steel plates and lightweight insulation layer, and many exterior walls of houses adopt lightweight and beautiful glass wall structure.
The interior partition wall can be filled with hollow block, aerated concrete or light steel keel gypsum board. At present, the roof waterproof layer of light steel structure building with aluminium alloy frame and glazed partition is uneconomical. Now, most of the roof waterproof layer is rolled material. The traditional cement mortar leveling layer and coke slag insulation layer are also abandoned on the roof, and lightweight insulation materials such as QN board and polyethylene concrete board can be used to make variations according to requirements and cancel the roof leveling layer. - The foundation forms of multi-storey light steel buildings are usually independent foundation under columns, strip foundation, cross foundation, and sometimes raft foundation. When using the independent foundation under column, attention should be paid to the influence of the relative uneven settlement of the foil foundation on the upper joints. Cast-in-place or prefabricated reinforced concrete structures are commonly used in foundation beams, sometimes steel foundation beams can also be used according to requirements, but usually the column footings and steel beams buried below the ground are encased with concrete, in order to solve the problem of anti-corrosion, the joints of multi-storey light steel structure buildings are mostly welded I-shaped or box-shaped sections.
Because the web of I-section is relatively thin, the connection between the weak axis direction and the beam is mostly articulated, while the strong axis direction is rigid. Sometimes semi-rigid connections can also be used, but their mechanical properties are complex, and more accurate design data are often obtained through experiments. At the same time, steel-bonded tendons of multi-storey buildings are relatively thin, so weld joints on site should be avoided as far as possible. In order to strengthen the fire protection and anti-corrosion measures of the whole rigid multi-storey light steel structure building, fire protection coatings, foaming paint and outer fire protection layer are mainly used in the fire prevention of steel structure in China. For exposed steel structural components, such as building tortuous and other multi-purpose coatings and paints, the fire resistance limit can reach 1.5-3 h by using 10-40 mm thick coatings, while the fire resistance time of foaming paint is generally 05h. For concealed components, perlite and vermiculite fire spraying or fireproof board is an economical and effective method. 30-40 mm thick spraying can achieve 1.5 h fireproof limit and one-sided anti-magic ability. Exposed steel trusses are usually composed of anti-magic corrosion coatings or paint anti-magic, primer and topcoat.
At present, the effective period of anti-magic paint is 10-20 years, so it should be repainted regularly. Galvanized profiled steel sheet itself has certain anti-magic ability. Fireproof coating can be used to solve the anti-magic problem when it is used in floor, but organic coating should be applied to roof and exterior wall, and its durability will be increased.