Abstract
A practical approach to design robust structures is summarized in the paper. To avoid progressive
collapse given the occurrence of local failure due to unidentified accidental situations, either alternative
load paths or fuses, i.e. predefined collapse mechanisms should be built into such systems. The proposal
includes a procedure to achieve correspondence between assumed and real mechanisms in case of failure
of any member on which the strength and stability of the system or subsystem depends. For the design
or assessment of such key members, risk-based target reliability indices are developed, and considerations
are made about the target reliability for the remaining system left standing after key member failure.