Advances in Seismic Design Methodologies - Earthquake Engineering for Structural Design - page 443

Advances in Seismic Design Methodologies 443

Figure 9.36 Structural and non-structural components (FEMA 74, 2005)

Direct effects. When a building is shaken during an earthquake, the base of the
building moves in harmony with the ground, but the entire building and the building
contents above the base will experience inertial forces. These forces depend on the base
acceleration of the site, the amplification of this acceleration with the height of the
point of attachment of the non-structural component above the foundation and its
weight. All non-structural components can be damaged due to the inertial forces, which
may cause overturning of slender objects or sliding of stocky objects (Fig. 9.37), if
these are not anchored or the attachment is inadequate. During a moderate earthquake,
damage to critical equipments and contents may be more important than damage to the
building itself. In addition, damage to such equipments can lead to an extended
business interruption, which may pose the greatest earthquake financial risks. In these
conditions, the proper design of connections between non-structural elements and
structure is of first importance. Frictional resistance of components and attachments
cannot be relied upon in seismic events.