System reliability bounds: A new look with improvements

Since the author's publication [Ramachandran K. System bounds: a critical study, Civil Eng. Syst., 1984, 1, 123-129.] of a critical review in 1984, only a few papers have been published on system bounds or structural reliability bounds. The purpose of this article is to update the progress made on system bounds during the last two decades and to highlight the issues that remain to be resolved. In this article, system bounds have been approached in a slightly different way, and improved methods of ordering of events are also given. These new bounds are better than existing ones.