Simplified fatigue assessment for earthquake losses: Cycle counting and fragility analysis to quantify damage

2017 Taylor & Francis Group, London. The Canterbury Earthquakes have brought the concept of low-cycle fatigue demands on structures to the forefront of post-event structure assessment. Methods are required to rapidly assess the proportion of a structures fatigue life that has been consumed by an earthquake and aftershock sequence to determine restoration requirements. First, the structural fatigue capacity is assessed for a nonlinear ductile structure response. Second, time-history analysis and cycle counting methods are used to determine the cumulative low cycle fatigue demand imposed upon a structure by the 20102011 Canterbury Earthquake Sequence for the Christchurch CBD. Results are presented as fatigue demand spectra. The effect of the fatigue demand is then assessed for a typical highway bridge that has been designed to New Zealand code provisions. Results show the Canterbury earthquake and aftershock sequence consumed some 50% of the total fatigue life for the bridge piers if the bridge was located within the Christchurch CBD. As low cycle fatigue damage is irreparable, a rebuild of the substructures of the bridge is deemed be necessary to restore the structure to a new condition.

Mechanics of Structures and Materials: Advancements and Challenges - Proceedings of the 24th Australasian Conference on the Mechanics of Structures and Materials, ACMSM24 2016

Simplified fatigue assessment for earthquake losses: Cycle counting and fragility analysis to quantify damage Conference Paper