Classification and structural design of architectural glass roof dome
As a kind of building exterior protection, architectural glass lighting roof has been widely used in various buildings, and it plays an important role in building envelope protection and decoration. The relationship between itself and the building, the force form of the structural system, the application of materials and the functional design are all special, which is different from the architectural curtain wall and other architectural decoration forms. Daylighting, shelter from wind and rain, changeable geometric shapes (shapes), and decorations (inside and outside) are important characteristics of architectural glass roofs. The corresponding structural forms and classification design should closely focus on these characteristics.
2. Classification of glass roof
Architectural glass roofs are formed and developed with the development of buildings. From ancient buildings to modern buildings, various forms of roofs have been formed. From the shape and shape, there are flat tops, slope tops, vault tops, domes, space curved tops, various flat geometric tops, single slope tops, double slope tops, semi-spherical tops, 1/4 spherical tops, and cones. Tops, polygonal cones, cones, domes, etc., and thus combined into a conjoined, group form. There are independent, embedded, and spine-riding forms for the relationship with the building. From this point of view, its modeling forms are diverse and diverse. From the perspective of its structural composition, there are also many supporting methods. In the early days, there were wooden structure supporting daylighting roofs, steel-wood combined supporting daylighting roofs, and modern buildings mainly include steel frame supporting daylighting roofs, aluminum frame supporting daylighting roofs, and steel-aluminum combined support. Daylighting roofs, glass-supported daylighting roofs, point-supported daylighting roofs, and point-supported daylighting roofs are divided into steel structure support, glass support, tie rod, cable support and combined support. There are two installation methods, split type and integral type (ie frame type and unit type). From the functional point of view, most of them are closed daylighting and heat-preserving daylighting roofs, but also open, sun-shading (or decorative), daylighting roofs and dynamic control types (which can be moved as a whole). Architectural glass roof is a key part of a building. There are multiple ways to deal with the building structure and load bearing. The waterproof construction process is difficult, and the internal and external visual effects are important. Therefore, its classification is particularly critical. There is a good classification method. The specific development of corresponding structural design and production and installation standards can ensure structural safety, reliable sealing, thermal insulation, good decorative effects, and reasonable production and installation processes. In view of the above problems, it is recommended to divide the following aspects.
2.1 According to the shape and shape: flat roof, slope roof, curved roof, special-shaped roof, combined roof. The shape is the intuitive expression of the lighting roof, and classification is necessary, but there are many types of subdivisions. According to their essence, they can achieve the same but small differences. The shapes can be attributed to the original shape and divided by the original shape. .
2.2 According to the vertical relationship with the roof, it is divided into independent roof, embedded roof and ridge-riding roof. The daylighting roof is inseparable from the building, and the combination with the building determines its force transmission method and structural treatment. The method should be divided reasonably, and the load parameters should be determined by the building shape. Special shapes should be tested in wind tunnels.
2.3 According to the function of use: closed thermal insulation roof, open roof, mobile roof. The use function determines the structural design form, the load transfer form, the production and installation of daylighting roofs are also different.
2.4 According to the supporting method: frame type supporting glass daylighting roof, point type supporting glass daylighting roof, unit type supporting glass daylighting roof, combined supporting glass daylighting roof. The supporting method of the glass roof is the essential division method of the structural design, which is selected according to the structural form in terms of design, production and installation. Therefore, the classification of the several major categories according to the support method is mainly based on the structure, the force transmission method, the production and the installation method. The lighting roof structure design is classified and designed according to the different supporting methods.
3. Structural design of daylighting roof
3.1 Frame-type supporting glass daylighting roof Frame-type glass daylighting roof is composed of facing materials, keel, connection structure, and sealing system. The facing material should be safety glass, laminated insulating glass or laminated glass, the minimum thickness of a single piece should not be less than 6mm, the laminated insulating glass must be selected for thermal insulation requirements, and the non-laminated glass and the laminated glass used separately should be tempered. The laminated film of laminated glass should not be less than 0.76mm. The keel is made of aluminum alloy profile, steel profile or steel truss, and the surface treatment meets the requirements of relevant material regulations, and meets the requirements of anti-corrosion, fire protection and decoration. The frame structure daylighting ceiling is divided into exposed frame, semi-hidden frame and hidden frame. The semi-hidden frame and hidden frame must be bonded with silicone structural adhesive, and the split bonding method is adopted, that is, the glass plate and the hidden frame are bonded in the factory. The attached board is bonded, and the on-site construction is connected by mechanical means. Hidden frame aluminum keel glass roof support structure can be divided into two-way keel system, one-way truss + one-way keel system, two-way truss and one-way truss + two-way single keel system, etc. The keel is hinged with the main structure. When the supporting point may have a large displacement, a supporting device suitable for the displacement should be adopted. The connection between the keels adopts a retractable structure, and a gap of 1.5 to 2.0 mm should generally be reserved. For the connection of multiple keel points, special connectors must be used to connect. The structure of the slope top is formed, and a special flooding is set on the top. Generally, the top of the structure does not adopt the hidden frame method, which is conducive to sealing and preventing water leakage.
3.2 Point-supported glass roof
The point-type glass roof is composed of facing materials, connection system, support system, connection structure, and sealing system. The glass adopts the same frame type glass roof, and the glass used is tempered. The thickness of the laminated glass laminated film should not be less than 1.14mm. The quadrilateral glass panel can be supported by four points, or when there is a basis, it can be supported by six points, and the triangular glass panel can be supported by three points. The thickness of the glass using the floating head connection system should not be less than 6mm, and the thickness of the glass using the countersunk connection system should not be less than 8mm (including the thickness of the single piece of insulating glass and laminated glass). The glass joints shall be caulked with silicon building sealant, which shall not be less than 10mm, and the displacement shall be calculated and selected according to the calculation results. Multiple sealing measures shall be adopted around the supporting hole. The supporting head should be able to adapt to the rotation and deformation of the glass panel at the supporting point, and a spherical hinge should be adopted. The supporting structure can use single section steel or steel pipe, truss, ribbed glass, tension rod and cable system, and combination system. The combination system is preferred for larger spans. The slenderness ratio of the compression member should not be greater than 150. Under the action of the wind load standard value, the deflection limit should be 1/300 of the span. For the tension rod and cable system, the deflection limit is 1/200 of the span of the supporting point. The structural design should fully consider the stability check calculation, and the overall stability and local stability should be checked separately, and structural treatment should be added.
3.3 Unit type supporting glass daylighting roof and combined supporting glass daylighting top In addition to the structural support requirements, the characteristics of its structural form must be fully considered, mainly the connection and sealing treatment. The hanging parts and supports of the plates should have an adjustable range to absorb the errors of on-site construction. The sealing treatment is considered according to different structures. The whole unit lighting roof is sealed with silica gel with the surrounding structure, and it is well connected with the surrounding drainage system. Split plate unit daylighting roof, the joints between the plates are sealed with silica gel, multiple sealing layers should be set inside, and internal drainage channels should be provided for organized drainage.
Installation stage: The glass panel has just been fixed, and the glass glue has not yet been constructed. The constraint state of the glass panel is that the two long sides are free sides and the two short sides are simply supported sides.
4 Conclusion
Glass roof is one of the special structural forms that are difficult to handle and use in architectural decoration. Its safety and functionality determine the multiplicity of structural applications. A lot of work requires in-depth research, experimentation and development by industry insiders. The sudden collapse of the glass roof of the Paris-Charles de Gaulle Airport and the glass roof of the Translucent Water Park in Moscow provided us with profound lessons. The structural design of the daylighting roof, the selection of materials, as well as processing, assembly and on-site installation are all key links. It is recommended to introduce the design requirements of damage safety concept and residual strength in the design of some large-scale daylighting roof structures to ensure a high degree of structural safety.
评论
发表评论