Interpretation and evaluation of NZS1170.5 2016 provisions for seismic ratcheting
Autor(en): |
Khaled Saif
Trevor Yeow Chin-Long Lee Gregory MacRae |
---|---|
Medium: | Fachartikel |
Sprache(n): | Englisch |
Veröffentlicht in: | Bulletin of the New Zealand Society for Earthquake Engineering, 1 September 2022, n. 3, v. 55 |
Seite(n): | 183-198 |
DOI: | 10.5459/bnzsee.55.3.183-198 |
Abstrakt: |
During seismic events, some structures have a tendency to ratchet and displace more in one direction than in the opposite direction after yielding, resulting in larger peak and residual displacements. Provisions to define the tendency for seismic ratcheting and the resulting displacement amplification are provided in the 2016 amendments of NZS1170.5. This paper presents some insight into the factors causing ratcheting, along with interpretation and evaluation of the proposed provisions. Firstly, the mechanics of seismic ratcheting due to dynamic stability, eccentric gravity loads, and unbalanced structural strengths in the back-and-forth directions are discussed. Afterwards, the new provisions were detailed and demonstrated by working through the NZS1170.5 commentary examples. The authors’ interpretation of the provisions is then presented, potential areas of confusion are identified, and wording changes to provide consistency and clarity are proposed. Finally, the displacement amplification factors provided in the 2016 amendments were evaluated using results of an independent study on single-degree-of-freedom reinforced concrete bridge columns subjected to eccentric gravity loading. It was found that the displacement amplification method proposed was reasonable, except when columns designed with a high ductility factor or which exhibit inelastic bilinear response had a significant tendency for ratcheting. |
Copyright: | © 2022 Khaled Saif, Trevor Yeow, Chin-Long Lee, Gregory MacRae |
Lizenz: | Dieses Werk wurde unter der Creative-Commons-Lizenz Namensnennung 4.0 International (CC-BY 4.0) veröffentlicht und darf unter den Lizenzbedinungen vervielfältigt, verbreitet, öffentlich zugänglich gemacht, sowie abgewandelt und bearbeitet werden. Dabei muss der Urheber bzw. Rechteinhaber genannt und die Lizenzbedingungen eingehalten werden. |
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10693005 - Veröffentlicht am:
23.09.2022 - Geändert am:
10.11.2022