In recent years, light steel structure has been widely used in factories, small exhibition halls and office buildings because of its low steel content, short design and installation time and high degree of industrial production.Therefore, the development of the steel structure enclosure system is diversified and diversified, which leads to the change of new thinking and new method of construction.
The enclosure system of light steel structure mainly includes metope system, roof system, daylighting belt, edge and pan water, gutter and thermal insulation cotton, etc.The enclosure system is one of the main components of the light steel structure, which determines the appearance of the building and the waterproof and thermal insulation effect of the building.
01.Design and construction of roof and wall system.
1.1 classification of color board enclosure system.
The color board is divided into: single layer board, EPS sandwich board, BHP color steel plate, GRC wall board, polyurethane sandwich board, glass silk cotton field composite sandwich panel, rock wool sandwich board.
The construction method is divided into: finished composite board, site composite board.The connection mode of the compound plate is divided into: lap plate, occlusal plate and dark gusset plate.
According to the materials: galvanized color steel plate, titanium plate, aluminum zinc coated steel plate, aluminum alloy plate pressure plate, stainless steel plate pressure plate, copper plate.
1.2 design considerations.
Because of its low machining cost and mature construction technology, the field composite board is widely used in light steel structure.Roofing color board colorful with 0.376t and 0.5t thick galvanized paint color board.
Roof pitch influence of roof runoff discharge, when the design roof pitch YiQu 1/8-1/20, more rain in the region YiQu larger values of these (see CECS102:98), in addition slope roof and the roof plate type, typically exposed screw type of plates with large slope requirements, the requirements of the hidden is smaller.
Large span steel structure roof board suitable for use of hidden color steel plate.In a large number of engineering applications, the hidden color steel plate shows the following advantages :(1) avoid the deformation of roof plates caused by temperature difference, and the self-tapping screw is cut.(2) in rainy areas, the typhoon area exposed self-tapping screw in deformation temperature, the vibration of the wind load, aging, rubber mat is very easy to cause plate corrosion and leakage, the dark buckle type mining steel can avoid the above situation.To shed length is more than 60 meters were two boards need to be processed into roofing, formed between expansion joints, with Thai covering plate connection, have to Thai cover plates with sliding between color plate, can solve the problem of temperature deformation.
1.3 construction considerations.
In construction of large span roof, color plate should be the whole piece of moulding board, plate deformation caused by the crane lifting plate easily, so the installation time is generally not used cranes, colorful hoist half inclined type hoisting.
02.Design and construction of daylighting beads.
Mining plate according to the material divided into glass fiber reinforced polyester plate, made of honeycomb carbon polyester or solid board, etc., according to the shape can be divided into the same as the roof plate waveform of glass fiber reinforced polyester mining board (hereinafter referred to as FRP lighting watts) and other flat or curved surface plate.
There are different fixed methods for different mining plates, and the polycarbonate mining plate is fixed with aluminum profile fasteners, and the corrugated mining plate is fixed with the support of the mining plate and the self-tapping screw, and then the rubber seal is sealed.The position of the stripper is generally set in the span.The mining plate is connected with the self-tapping screw and must have a cover plate.The hot and cold deformation of the sun plate is easy to be cut by self-tapping, so the sun board should open a larger hole in the tapping.The scale of the stripper should be considered when installing the lighting panel.
Mining 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 choi steel board type, 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 is need to do.
The longitudinal length of the drawing board shall be set in the vicinity of the sandbar. The roof waterproof treatment shall be coated with sealant, and the surface of the sealant is easy to be aged.A white or colorless sealant sandwiched between two water gels is used in the connection.
By lateral color plate plate lap: bright type screw roof panel or dark fit type roof board, mining plate plate effective width should be reserved, in the mining plate wave with self-tapping screws, considering the mining plate heat bilges cold shrink, dealing with mining plate an advisable) (8 mm hole punching processing, self tapping screw should be placed under the reinforced waterproof washer, prevent mining plate heat bilges cold shrink after cracking the screws.
03.Protect wet cotton
Thermal insulation cotton is made of rock wool, glass fiber and other materials. It has excellent thermal insulation performance, convenient construction and installation, remarkable energy saving effect and low thermal conductivity.At present, the roof system of domestic steel structure is mainly used :(1) steel wire mesh + aluminum foil insulation cotton + single color board;(2) double-layer color board + insulation cotton, etc.
The following is mainly about the construction method of steel wire mesh + aluminum foil insulation cotton + single color board roofing:
Pull the stainless steel wire or galvanized wire cross diamond shaped or rectangular shape, with 215 centimeters long tapping screw in purlin, laying glass cotton lap blanket, toward the interior side, on aluminum foil surface is perpendicular to the purlin, the two sides in the roof of about 20 centimeters of roll mat, stay with double sided tape should be fixed on the outer Zha purlin.Use the reserved 20cm patch for the glass wool.Note the tension and alignment of the glass cotton felt, the seam between the coil and the volume, and the connection should be arranged in the purline.According to the engineering requirement, to avoid the generation of the cold bridge, we can consider the hard insulation material on the purline.
04.Gutter and cornice.
The cornice can be divided into three forms: outer drainage roof, inner drainage roof, and free fall.It can give priority to free fall and outer drainage.According to the material, there are stainless steel gutter, steel plate gutter, color plate tiangou.As the main drainage system of roof, the gutter decides the discharge of rain and snow and the normal function of building roof.
FIG. 1 the schematic diagram of insulation cotton under the gutter.
In the cold region, the temperature difference between indoor and outdoor temperature is large in winter, and the condensation water will appear in the inner gutter. Therefore, it is required to lay insulation cotton under the gutter. In the construction, it can be used as shown in figure 1.The insulation cotton is fixed by hanging the purline of the gutter.At the same time, add an edge at the bottom of the gutter (commonly used color steel plate), as shown in the figure, the edge A is beautiful and can be fixed with the insulation cotton.
In the northern areas with little rain, and the project is not high enough for the cornice, it can be used freely, and the cornice can be picked out from the wall, and the wall should not be less than 300 mm.If the wall panel is a single board, the indentation between the wall panel and the roof panel shall be blocked by the special plate type retaining wall.When the roof slope is less than 1/10, the trough of the roof board is bent down 5 to 10 mm with the clamp down.
FIG. 2 outer drainage trench cornice.
The outer drainage roof cornice has been widely used in engineering because of its good leak-proof and low cost.The outer drainage cornice and gutter of the gutter have been mined.Construction the lottery board roof gutter don't need to support its structures, its groove wall panels of press close to, can directly with outside support is set on the wall, stretched out on the roof board outside wall fittings pick in the gutter, paragraphs cullis overlap each other, connected by rivets and sealing glue sealing.The procedure can be used in the project in figure 2.
FIG. 3 package edges and flooding practices.
05.Edge and water
The edge and flood water not only delineate the lines of the building, but also affect the aesthetics of the building. Meanwhile, the structure is connected into a whole, preventing wind and rain, making the building stronger and more durable.See figure 3 for details.
06.Summary and conclusion
Light steel structure has been widely used in factories, small exhibition halls and office buildings because of its low steel content, short installation and design time and high degree of industrial production.The design and construction experience of color steel plate maintenance system is often used in its enclosure system, and it is of great practical significance to put forward the economic reasonable node construction and construction plan.
For floor plate type level, should first USES the color dark buckle type steel structure processing, can avoid the self-tapping screw temperature deformation was cut, at the same time can be avoided in rainy area, the typhoon area exposed self-tapping screw in the deformation temperature, the vibration of the wind load, aging of rubber mat plate corrosion and leakage phenomenon.
In the design and construction of the mining plate, it should pay attention to its thermal expansion and contraction.Pay attention to the difference of color steel plate.The mining plate should be prepunched (8mm hole).
In order to avoid the production of cold bridge, we can consider the hard insulation composite plate on the purline.
In the north, the area of low rainfall and engineering to the cornice is not very high, it is suggested to use the free falling cornice.It has good leakproofness and low cost. It is widely used in engineering.