The macro-models method is one of the main categories for modeling
infills based on the equivalent strut method. The basic parameter of these
struts is their equivalent width, which affects the stiffness and strength. This
paper presents a general review of several expressions proposed by
researchers to calculate this equivalent width. The comparative study of
different expressions shows that the Paulay and Priestley equation is the
most suitable choice for calculating the diagonal equivalent strut width, due
to its simplicity and because it gives an approximate average value among
those studied in this paper. Consequently, the model will be used in our
further study for analysis of RC infilled frames.