Seismic loss assessment considering low-damage repair of non-structural components

Seismic loss assessment is a powerful tool for understanding potential losses in future earthquakes and supporting decision-making in the design of new buildings or retrofit of existing ones. Following the methodology of FEMA P-58, annualised economic losses can be calculated, but on the basis that the building’s seismic vulnerability does not change with time. This does not reflect the reality of many real-world cases where owners have opted to replace earthquake damaged building components with new low-damage solutions. In this work, seismic loss assessment is carried out using a novel approach that simulates sets of earthquakes over the anticipated life of the building. Considering all events in sequence, the building model can be updated to reflect changes that might be made post-earthquake or simply through elective interventions. Losses are calculated for an example 12-storey steel moment resisting frame building, hypothetically located in Wellington, New Zealand, assuming that severely damaged non-structural components are replaced with new low-damage components following each event. Different configurations of non-structural components are considered, along with different assumptions on how damaged components are repaired following an event. It is shown that for buildings with very fragile non-structural components, assumptions on the post-earthquake repair of non-structural components can have a notable effect on the expected annual loss parameter. This is important when considering cost-benefit analyses for making decisions on retrofitting non-structural components in existing buildings.