This paper presents a general
probability based effective stiffness model which determines the relationship
between
the member stiffness reduction and the bending moments due to the
applied loadings on the members. The most significant feature of this model is
the applicability to
structural members subject to various loading types and
can be considered as a constitutive model for members in all forms of
reinforced concrete buildings. To determine the accuracy, limitations and
applicability of the proposed model at the member level, a series of large
scale beam tests were conducted. Once an appropriate member level model was
determined full scale, tall building, structural sub-assemblages were tested in
the sidesway mode with constant applied gravity loads.