The interfacing of glazing with other elements of construction is an important consideration, as each material component will have its own design, procurement and dimensional attributes. Guidance on interfaces is given in the SCI publication Steel Supported Glazing
Systems and in Structural Use of Glass. The direct attachment of the glass panel to the support structure is often at discrete points rather than being continuous along the edges in more conventional glazed panels.
Pilkington's 'planar glazing system uses special bolted attachments which provide a more uniform bearing pressure on the glass, thereby increasing the local resistance to in-plane and out-of-plane forces. These attachments are not generally directly supported by the primary structure, but indirectly through a secondary element which provides for some articulation and adjustment for tolerances.
Planar glazing is often combined with articulated nodes which attach two or four panels of glass at their corners. The planar glazing system used at Heathrow Airport Visitor's Centre was attached to the supporting steel sections by means of stainless steel fixings, and provided a fully glazed yet acoustically sealed corridor along the runway side of the building (see Figure 9.4).
The detailing of the interfaces between the glazing and its support structure is critical and should take into account:
9.3 Sloping glazing details at Western Morning News, Plymouth (architect: Nicholas Grimshaw & Partners)
9.5 Typical bolted attachment to glazing showing the various components
Glazing support attachment
• appropriate construction and manufacturing tolerances
• the movement of glazing panels and support structure due to thermal effects and wind or other applied loadings
• the loads that arise due to the self weight of the system and external actions — the load transfer effects that may occur when glazing panels are broken or removed should also be considered.
If movement cannot be accommodated, stresses are developed that can result in the distortion of members or, more likely, the breakage of the glass panes. The local attachment details should provide for the necessary adjustment. The detail in Figure 9.5 achieves this by use of slotted holes and adjustable bolted attachments to the supporting members.
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