Reliability of Parallel Structural Systems

Abstract

A parallel structural system is one in which more than one critical section must reach a limiting state before the structure as a whole can reach a limit state. An obvious example is the plastic analysis of redundant frameworks in which individual member strengths can be maintained while the structure deforms to mobilize the strength of all those members which can add to its ultimate load capacity. In a reliability analysis, the effect of member strength correlation may be an important parameter governing the reliability of the whole system. This aspect is investigated in this paper. It is shown by means of a series of examples of relatively simple frames that the reliability of the system is sensitive mainly to correlation between the member strengths within the one member or between related members. However this sensitivity varies with the dominant collapse mode for the frame.