| dc.creator | Hulsey, Anne | en |
| dc.creator | Elwood, Ken | en |
| dc.creator | Horspool, Nick | en |
| dc.creator | Gerstenberger, Matt | en |
| dc.creator | Sullivan, Timothy | en |
| dc.date | 2025-06-01 | |
| dc.date.accessioned | 2026-07-14T20:44:50Z | |
| dc.date.available | 2026-07-14T20:44:50Z | |
| dc.identifier | https://bulletin.nzsee.org.nz/article/view/1690 | |
| dc.identifier | 10.5459/bnzsee.1690 | |
| dc.identifier.uri | https://repo.nzsee.org.nz/xmlui/handle/nzsee/2871 | |
| dc.description | The current New Zealand seismic design provisions are expected to be updated with a proposed Technical Specification (TS). The update is motivated primarily by the recent release of the 2022 National Seismic Hazard Model, with new seismic hazard estimates across the country. The updates are being carried out by the Seismic Risk Working Group (SRWG). One of the SRWG’s primary intentions for the proposed TS was to maintain the Building Code objective of safeguarding people from injury in light of these hazard changes. While previous code development in New Zealand has not explicitly assessed whether the life-safety risk was tolerably low, the SRWG sought to implement a new life-safety risk assessment methodology. The risk assessment takes an Ultimate Limit State (ULS) design spectrum as input and provides an expected distribution of the fatality risk, representing the variety of buildings that could be designed in accordance with the minimum requirements associated with ULS. The methodology is made up of four modules representing (A) the shaking hazard, (B) the building performance (collapse fragility), (C) the probability of fatality given collapse, and (D) the variability in performance among code-conforming buildings. The first three modules quantify fatality risk for a single building, while the fourth module iterates over many buildings to produce a full risk distribution. Using this methodology, the SRWG found that for Importance Level 2 (IL2) buildings, a ULS design spectrum with an annual probability of exceedance (APoE) of 1/500 typically corresponds to an annual individual fatality risk (AIFR) ranging between 10−6 and 10−5. Comparison with the ULS design spectra from the current NZS 1170.5:2004 provisions shows that the proposed spectra result in more uniform risk across the country, across different site classes, and across different periods. Additionally, the IL3 ULS design spectrum with an APoE of 1/1000 was considered, demonstrating that increasing the importance level to mitigate mass casualty events in high occupancy buildings is functionally equivalent to reducing the tolerable AIFR level. In summary, the risk assessment methodology can provide valuable information to the code development process by evaluating and comparing the life-safety risk associated with various options for the ULS design spectra. | en |
| dc.format | application/pdf | |
| dc.language | en | |
| dc.publisher | New Zealand Society for Earthquake Engineering | en |
| dc.relation | https://bulletin.nzsee.org.nz/article/view/1690/1510 | |
| dc.rights | Copyright (c) 2025 Anne Hulsey, Ken Elwood, Nick Horspool, Matt Gerstenberger, Timothy Sullivan | en |
| dc.rights | https://creativecommons.org/licenses/by/4.0 | en |
| dc.source | Bulletin of the New Zealand Society for Earthquake Engineering; Vol. 58 No. 2 (2025); 118-132 | en |
| dc.source | 2324-1543 | |
| dc.source | 1174-9857 | |
| dc.title | Assessing the life-safety risk for the proposed technical specification (TS) 1170.5 | en |
| dc.type | info:eu-repo/semantics/article | |
| dc.type | info:eu-repo/semantics/publishedVersion | |
| dc.type | Article | en |
