“…Under certain restrictions, the theory of plasticity allows the prediction of the collapse load by means of the limit analysis based on the bound theorems (Drucker et al, 1952 União,in this case coupling such theorems with the finite element method, as originally proposed by Lysmer (1970) and Bottero et al (1980). This is a straightforward approach for computing lower and upper bounds on the load at incipient collapse which have gained increasing attention (Lyamin and Sloan, 2002;Krabbenhoft and Damkilde, 2003;Makrodimopoulos and Martin, 2006;Yu and Tin-Loi, 2006;Ciria et al, 2008;Munõz et al, 2009;Le et al, 2010;Bleyer and de Buhan, 2014;Nguyen-Thoi et al, 2015). This is partly due to the development of robust optimization methods and solvers on which they strongly rely (Drud, 1996;Sturm, 1999;Lyamin and Sloan, 2002;Murtagh and Saunders, 2003;Tütüncü et al, 2003;Andersen et al, 2003;Krabbenhoft and Damkilde, 2003).…”