“…In this context, the adopted technique may be regarded as belonging to the well known family of Sequential Linear Programming (SLP), which is no more than an iterative process in which linearized approximations are used in any particular iteration [51][52][53]. It is worth mentioning that SLP schemes have been adopted by many authors in the recent past for the limit analysis of slabs, see for instance Johnson [51,53] and Ramsay and Johnson [52] making use of triangular linear elements and by the Author for in-plane problems with rigid elements [50]. While triangular elements with linear edges are adequate for out-of-plane problems as shown in [51][52][53], such an approach may give an overestimation of the actual collapse loads in the case of coupled problems or when slip lines are generally non linear, as the case here treated.…”