Nonlinear equilibrium paths of a deep arch under concentrated downward load P
From the same paper as the previous 3 images.
The DaDeppo reference is:
DaDeppo, D.A. and Schmidt, R. (1975), “Instability of clamped-hinged circular arches subjected to a point load”, J. Appl. Mech. Trans. ASME, 42, 894-896