Energy Method for Incremental Collapse Analysis of Framed Structures

Abstract

The entire spectrum of incremental collapse behavior of elastic‐perfectly plastic multistory rigid‐frame structures can be described by energy methods. The separation between safe and unsafe load ranges coincides precisely with the transition from bounded to unbounded hysteresis energy absorption. The energy method is preferable to alternate methods that rely on linear programming methods for computation of the envelope, which bounds “safe” loading regimes. This is because the energy method leads to a sharp demarcation between shakedown and incremental collapse, which can be exploited to produce a highly efficient computer program. Illustrative results from the application of the energy method are given for a three‐bay, three‐story rigid‐frame structure.