1. Thermal insulation and fire protection of steel
Steel has very high thermal conductivity, and its thermal conductivity is 50W (M. ℃). When it is heated to more than 100 ℃, its tensile strength will decrease and its plasticity will increase; when the temperature reaches 250 ℃, the tensile strength of steel will slightly increase, but its plasticity will decrease and blue brittleness will appear; when the temperature reaches 500 ℃, the steel strength will drop to very low, which will cause the steel structure to collapse. So when the environment temperature of steel structure is above 150 ℃, it is necessary to do the design of heat insulation and fire protection.
2. Roof support system and roof design
The layout of roof support system shall be determined according to the span, height, column grid layout, roof structure, crane tonnage and seismic fortification intensity of the area. Generally, the roof structure with purlin or without purlin system shall be provided with vertical support; in the system without purlin, the large roof panel has three points welded with roof truss, which can play the role of top chord support, but considering the limitations of construction conditions and installation needs. Whether there is purlin or no purlin system, roof truss top chord and skylight truss top chord shall be provided with top chord transverse support. Longitudinal horizontal support shall be provided for the workshop with roof truss spacing of not less than 12m or the workshop equipped with super heavy bridge crane or the workshop equipped with large vibration equipment. Share from Huaxin Building. At present, there are two common practices of steel structure roof on the market: ① rigid roof: double-layer color profiled steel plate with insulation cotton inside; ② composite flexible roof: composed of roof color steel plate inner plate, air separation layer, insulation layer and coiled material waterproof layer.
3. Setting of temperature expansion joint
The change of temperature will cause the deformation of the steel structure workshop and the temperature stress of the structure. When the plane scale of the workshop is large, in order to avoid the large temperature stress, temperature expansion joints should be set in the vertical and horizontal directions of the workshop. The length of the section can be implemented according to the steel structure specification. The temperature expansion joint is generally treated by setting two columns. For the longitudinal temperature expansion joint, rolling support can be set at the roof truss support.
4. Antirust treatment
The surface of steel structure will be corroded when exposed to the atmosphere directly. When there is corrosive medium in the air of steel structure workshop or steel structure is in the humid environment, the corrosion of steel structure workshop will be more obvious and serious. The corrosion of the steel structure will not only reduce the cross-section of the component, but also cause rust pits on the surface of the steel component. When the component is stressed, it will cause stress concentration and premature failure of the structure. Therefore, enough attention should be paid to the corrosion prevention of steel structure plant components, and corresponding countermeasures and measures should be taken in general layout, process layout, material selection and other aspects according to the corrosion medium conditions and environmental conditions of the plant to ensure the safety of the plant structure. Anti rust primer and top coat are often used for corrosion protection of general steel structures. The number and thickness of coating layers are usually determined by the application environment and coating properties. Generally, under the action of natural atmospheric medium, the coating thickness of indoor steel structure is required to be 100 μ m, that is, two coats of primer and two coats of finish. For open steel structure or steel structure under the action of industrial atmospheric medium, the total thickness of paint film is required to be 150 μ m ~ 200 μ M. In addition, chlorosulfonated anti acid paint is required for steel structure in acid environment. The steel column base below the ground shall be wrapped with concrete not less than C20, and the thickness of its protective layer shall not be less than 50mm.
5. Facade design
The construction of light steel structure mainly has the following four characteristics: scale, line, color and change.
The facade of the steel structure workshop is mainly determined by the process layout. Under the requirements of the process, the facade shall be simple and magnificent and the nodes shall be simple and unified as much as possible. The color profiled steel plate makes the building of light steel workshop appear light and colorful, which is obviously superior to the traditional reinforced concrete structure. In the design of light steel factory buildings, jumping colors and cold colors are often used, with emphasis on the main entrances and exits, outer gutters, closing and flashing, which not only reflects the magnificent momentum of modern factory buildings, but also enriches the facade effect.
In a word, the design of steel structure workshop should be based on its characteristics. The architectural structure design should be carried out according to its characteristics to make the design safe, reliable, economical, reasonable and beautiful.