2. Vierendeel trusses are rigidly-jointed trusses having only vertical members
between the top and bottom chords. The chords are normally parallel or near
parallel.
Elements in Vierendeel trusses are subjected to bending, axial force and shear
, unlike conventional trusses with diagonal web members where the members
are primarily designed for axial loads.
Vierendeel trusses are usually more expensive than conventional trusses and
their use limited to instances where diagonal web members are either
obtrusive or undesirable.
Vierendeel trusses are moment resisting. Vertical members near the supports
are subject to the highest moments and therefore require larger sections to
be used than those at mid-span. Considerable bending moments must be
transferred between the verticals and the chords, which can result in
expensive stiffened details.
3. Connections
Vierendeel trusses have rigid joints which must transfer significant bending
moments, especially near the supports. Welded joints are therefore common
and may involve significant local reinforcement of the members at the joint. If
joints are bolted, substantial connections will be necessary, generally using
pre-loaded bolts.
4. Commerzbank, Frankfurt
Architect: Norman Foster
Engineer: Ove Arup
Floors between sky gardens
are supported by eight-story
high Vierendeel frames which
also resist lateral load.