Initial bolt forces have relationship with collapse modes through t-stub flange thickness showing that the lines of tcriijmn defined in reference[2] except a mode, in which faying surfaces are separated, are having a common point. β(the ratio of an initial bolt force to yield bolt force) being the abscissa of the point and t(flange thickness) is determined by the stub dimensions except flange thickness. The collapse modes indicated by β and t are divided into four regions, in which each collapse characteristic is distinguishable.
