Design and Construction of Enclosure System of Light Steel Structure(1)

In recent years, light steel structure has been widely used in workshops, small exhibition halls, and office buildings because of its small amount of steel, short design and installation time, and high degree of industrial production. This promotes the development of the steel structure enclosure system from the simple to the diversified and then leads to the change of new design ideas and new construction methods.

The enclosure system of light steel structure mainly includes wall system, roof system, skylight belt, package edge and flood water, gutter and insulation cotton, etc. The enclosure system is one of the most important components of light steel structure, which determines the ornamental degree of building appearance, the waterproof and thermal insulation effect of the building.

Design and construction of roof and wall system

A.Classification of the color plate enclosure system

The color plate enclosure is divided into the single-layer board, EPS sandwich board, polyurethane sandwich board, fiberglass wool field composite sandwich board and rock wool sandwich board according to the composition mode.

According to the construction method, it is divided into: finished composite board and on-site composite board. The connection mode of the field composite plate is divided into: lap plate, bite plate and hidden gusset plate.

According to the material, it is divided into galvanized color steel plate, titanium plate, aluminum zinc color steel plate, aluminum alloy plate, stainless steel plate and copper plate.

B.Design considerations

Site composite plate is widely used in light steel structures because of its low processing cost and mature construction technology. Roof color plate with 0.376T and 0.5T thick galvanized paint color plate.

Roof slope affects the discharge of roof rainwater. In the design, the slope of the roof is suitable for 1/8-1/20, and the larger value is suitable for areas with more rainwater (see CECS102:98 for details). In addition, the slope of the roof is related to the type of roof panels used.

Large-span steel structure roof panels should adopt a hidden-button type color steel plate.

In a large number of engineering applications, the hidden button type color steel plate shows the following advantages: (1) to avoid the roof deformation caused by temperature difference is too large, the tapping screw is cut off. (2) in rainy areas, typhoon area exposed tapping screw in temperature deformation, wind load vibration, rubber pad aging, it is very easy to cause rust and water leakage of the plate, the use of hidden button mining steel plate can avoid the above situation.

C.Precautions for construction

In the construction, for the large-span roof, the color plate needs to be formed as a whole plate. Because the crane lifting plate is easy to cause the plate deformation, it is generally not used when installing the crane, and the colorful hoisting machine is half-inclined.

Lighting belt design and construction

Light plate according to the material is divided into glass fiber reinforced polyester light plate, poly carbon fat made of honeycomb or solid board, according to the shape can be divided into the same waveform with the roof plate glass fiber reinforced polyester light plate (referred to as glass fiber reinforced plastic lighting tile) and other plane or curved light plate.

The different light plate has different fixing methods, polycarbonate light plate is fixed by aluminum profile fastener, waveform light plate is fixed by light plate bracket and self-tapping screw connection, and then sealing. The position of the light plate is generally arranged in the middle of the span. The light plate must be connected with the tapping screw with a cover plate. The hot and cold deformation of the sun plate is large, and it is easy to be cut by the tapping nail, so the sun plate should open a large hole in the tapping nail. In the installation of the light plate to consider the scalability of the light plate.

Light plate without overlapping within 12 m, more than 12 m requires the lap, lap length is 200-400 - mm, take it the second sealing glue, transverse glue need not on, longitudinal lap steel plate needs to see the type of the steel plate, ordinary pressed steel plate, generally do not take an examination of virtual do as, directly with the color plate with tapping screw, and the seal sealing glue, bite plate needs to do.

The longitudinal length direction of the light plate should be set near the sandalwood strip. The roof waterproof treatment must be coated with sealant, and the surface of the sealant is easy to age. A white or colorless sealant is sandwiched between two water mastic joints.

By lateral color plate lap: bright type screw roof panel or dark fit type roof board, light plate effective width should be reserved, in the light plate wave with self-tapping screws, considering the light plate heat bilges cold shrink, should adopt pre-punching processing (8mm hole is appropriate), self-tapping screws need to be placed under the enhanced waterproof gasket, to prevent the light plate thermal expansion and cold contraction after cracking at the screw.