Advanced Analysis and Design of Spatial Structures
Modern limit-state design codes are based on limits of structural resistance.
To determine the 'true' ultimate load-carrying capacity of spatial structures,
an advanced analysis method which considers the interaction of actual
behaviour of individual members with that of the structure is required. In
the present work, a large-displacement inelastic analysis technique has been
adopted to compute the maximum strength of spatial structures considering
both member and structure instability. The actual behaviour of individual
members in a spatial structure is depicted in the form of an inelastic strut
model considering member initial imperfections as 'enlarged' out-ofstraightness.
The maximum strength of the strut is computed based on a
member with 'equivalent out-of-straightness' so as to achieve the specification's
strength for an axially loaded column. The results obtained by the
strut model are shown to agree well with those determined using plastic-zone
analysis. The nonlinear equilibrium equations resulting from geometrical and
material nonlinearities are solved using an incremental-iterative numerical
scheme based on generalised displacement control method. The effectiveness
of the proposed advanced analysis over the conventional analysis~design
approach is demonstrated by application to several space truss problems.
The design implications associated with the use of the advanced analysis are
discussed. © 1997 Elsevier Science Ltd