To view this page ensure that Adobe Flash Player version
11.1.0 or greater is installed.
for Windy Vibrations
by Mahmod Samman, PhD, PE, FASME
Photo © BigStockPhoto/Chris Nolan
BALCONY RAILINGS COME IN DIFFERENT
SHAPES, MATERIALS, AND STYLES. WHEN
RAILINGS ARE INSTALLED IN HIGH-WIND AREAS,
DESIGN TEAMS MUST VERIFY THE ADEQUACY OF
THEIR DYNAMIC CHARACTERISTICS IN ORDER
TO ENSURE OCCUPANT SAFETY AND COMFORT.
One of the most common railing designs is an
aluminum frame with vertical pickets (Figure 1).
The popularity of this material is attributed to a
combination of factors such as:
• rust-resistance; and
• relatively low material and installation costs.
From a structural standpoint, balcony railings are
primarily designed to withstand mechanical loads
imposed by occupants. Since this design criterion can
be easily met using a metal like aluminum, the need
to produce less-expensive options resulted in products
designed to minimize weight.
In many applications, new lighter-weight aluminum
railings still work because they satisfy structural
requirements and applicable safety standards. However,
in high-rise buildings, especially in coastal areas, these
products can suffer from a serious, previously unknown,
functional failure. The lighter structural members can
become ﬂexible enough to experience resonance under
wind excitations. When this happens, the resulting
noise and vibrations can make these costal properties
virtually uninhabitable. Additionally, the dynamics
of resonance can cause fatigue damage in these
structural members that can lead to structural failure
of connecting welds.
54 the construction speciﬁer | april 2013
3/14/13 11:49:26 AM