Permissible limit state (PLS) analysis

Bridge owners rarely observe failures occurring at the Ultimate Limit State (ULS). However, when a loading (traffic) regime changes, a bridge in good condition may degrade rapidly, then becoming unserviceable.

The Permissible Limit State (PLS) is described in CIRIA C800 and permitted by National Highways CS 454 for UK road bridges. Specifically, the guidance promotes the use of the Permissible Limit State (PLS), the point beyond which progressive load induced degradation occurs under service loads during the intended life of a bridge.

LimitState:RING allows analysis of the Permissible Limit State (PLS) through the application of PLS-specific partial safety factors and material response parameters.