Conventional design does not exclude risk of local damage to a structu
re due to accidental events. Safety of the structure can be improved b
y ensuring that failure of any of its components does not cause, withi
n an appropriate level of reliability, collapse of the whole structure
or a major part of it. In this paper reliability of multistory framed
structures subjected to column failure is investigated using a probab
ilistic method. The method is based on a combination of a nonlinear fi
nite-element structural model and a first-order reliability method. Un
certainties in material properties, geometry, loads, and the structura
l model itself are taken into account, and their influence on frame re
liability is considered. The uncertain parameters appropriate td the s
trength of reinforcing steel, live load, and the model uncertainty are
found to have a major influence on the frame reliability. For three-s
pan frames with different numbers of stories and span-length ratios, c
ritical cases of column failures are identified. As a result it is pos
sible to restrict the number of examined structures. Finally, a simpli
fied probabilistic method is proposed for the reliability assessment o
f damaged frame structures.