Glazing are referred to the panels that are fixed into the aluminum or other types of frames to curtain wall construction. Commonly, there are various techniques which can be used in the construction or placement of glazing panels; glaze panels might be glass or other materials.
These methods glazing panel construction will be discussed in the following sections.
Fig.1: Curtain Wall, Glaze Panels are Fixed into Frames
Types of Glazing Panels and Methods
Glazing methods are provided as follows:
- Dry glazed
- Wet glazed
- Point supported glass systems
- Cable net
- Double skin wall
In this approach, compression stresses are applied to fix metal panels or glass units into the glazing pocket of the frames. The necessary compression force can be obtained using rubber gaskets and occasionally structural tapes.
Generally, the rubber gasket, which is compressed in advance, are placed on either side of the glazed element, and panels may be glazed from the exterior or interior based on the system.
Fig.2: Dry Glazed
Fig.3: Dry Glazed System with Rubber Gasket used in the Oldcastle Building, United States
In this technique, the infill element is placed and attached to the frame using proper attaching agents such as silicone sealant. The sealant application process should be conducted properly otherwise the attachment agent would not work suitably. For example, the perimeter need to be prepared sufficiently and then the sealant element is applied to the perimeter.
Structural silicone glazing as shown in figure-4 is a particular kind of wet glazed utilization that need utmost attention and observation of the sealant. The process begins with applying the adhering agent to the aluminum frame and then the panel is placed into its position.
The silicone would create a bond, which can withstand lateral loading, between the aluminum frame and the panel.
It is recommended to carry out such process in closed spaces such as factories and shops since the adhesion of the agent would decease when dusts are present on the surfaces.
The structural silicone glazing can be made for one or two storey heights. Figure-5 illustrates the direction of the structural silicone glazing applied in a multi storey building.
Fig.4: Structural Silicone Glazing
Fig.5: Structural Silicone Glazing
Point Supported Glass Systems
This system has been used since 1960s and it has undergone some development but its basics remain the same. It consists of strengthened or tempered glass through which holes are provided to attach it to the structure using proper means such as bolted fittings as shown in Figure-6 and Figure-7.
It can be observed form these figures that the fittings cause smallest obstruction of views due to their small sizes. The glass is commonly tempered by exposing it to high degree of temperature during its processing. This will reduce possible damages during its life service.
Fig.6: Fitting in the Point Supported Glass System
Fig.7: Various Configuration of Point Supported Glass Systems
Fitting manufacturing are mostly controlled by architectural intent. Point supported systems are considerably pleasing aesthetically but it needs great cautions to obtain required detailing and precision.
The analysis of point supported system is quite complicated and it may need to use finite element modeling to specify loads transfer and stress through an by fittings.
Fig.8: Point Supported Glazing System
Cable is another type of glazing panel construction that provide substantial views. It is an elegant glazing panels that does not need framing but it could be costly and expensive.
Due to the effect on loading on the panels, not only does cable net structural analysis is required to be carry out accurately but also construction works need massive coordination.
Cable net walls are commonly flexible that is why they are likely to deflect extremely. This may make occupants uncomfortable but the functionality of the building will not be influenced and its aesthetic views would not be distorted.
Fig.9: Use of Cable Net in UBS Tower, Chicago, United States
Double Skin Wall
This type of curtain is considered to be the most expensive compared to other ordinary types of panel construction.
Fig.10: Double Skin Façade
Double skin wall construction is quite complex and consist of two skin of glass or façade, and the space between the facades is employed to manipulate energy comes from sunlight and ventilation are installed that employs the warm air in the space between glass walls. It should be said that the ventilation could be natural, fans, or mechanically controlled.