What lateral forces must be absorbed by the structural framing when fixed glass is used as a curtain wall?

The primary lateral force that must be absorbed by the structural framing when fixed glass is used as a curtain wall is wind. Curtain walls are typically supported by a building's framing system and are designed to be non-structural, meaning they do not carry the load of the building but rather serve as an outer covering. Wind pressure can exert significant lateral forces on the exterior surfaces of buildings, including fixed glass curtain walls.

When strong winds occur, the pressure exerted on the curtain wall can lead to bending, shear, and other stresses in the structural framing that supports the glass. It's critical for engineers to calculate potential wind loads during the design process to ensure that the structural framing is adequately reinforced to handle these forces without compromising the integrity of the glass.

Other forces such as earthquakes, thermal expansion, and vibrations do impact buildings and may influence certain design considerations, but they are not the primary lateral forces that curtain walls absorb under normal circumstances, particularly with fixed glass. Earthquake forces are usually handled with different structural strategies. Thermal expansion is managed through the design of the materials and joints, while vibrations can be mitigated through various construction methods. Nonetheless, when focusing on lateral forces specifically related to the glass surface, wind is the crucial factor.