Derivation of new SAC/FEMA performance evaluation solutions with second-order hazard approximation
Article first published online: 15 OCT 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Earthquake Engineering & Structural Dynamics
Volume 42, Issue 8, pages 1171–1188, 10 July 2013
How to Cite
Vamvatsikos, D. (2013), Derivation of new SAC/FEMA performance evaluation solutions with second-order hazard approximation. Earthquake Engng. Struct. Dyn., 42: 1171–1188. doi: 10.1002/eqe.2265
- Issue published online: 13 MAY 2013
- Article first published online: 15 OCT 2012
- Manuscript Accepted: 17 SEP 2012
- Manuscript Revised: 14 SEP 2012
- Manuscript Received: 12 JUN 2012
- European Research Executive Agency via Marie Curie. Grant Number: PCIG09-GA-2011-293855
- seismic performance evaluation;
- probabilistic methods
A novel set of SAC/FEMA-style closed-form expressions is presented to accurately assess structural safety under seismic action. Such solutions allow the practical evaluation of the risk integral convolving seismic hazard and structural response by using a number of idealizations to achieve a simple analytical form. The most heavily criticized approximation of the SAC/FEMA formats is the first-order power-law fit of the hazard curve. It results to unacceptable errors whenever the curvature of the hazard function becomes significant. Adopting a second-order fit, instead, allows capturing the hazard curvature at the cost of necessitating new analytic forms. The new set of equations is a complete replacement of the original, enabling (a) accurate estimation of the mean annual frequency of limit-state exceedance and (b) safety checking for specified performance objectives in a code-compatible format. More importantly, the flexibility of higher-order fitting guarantees a wider-range validity of the local hazard approximation. Thus, it enables the inversion of the formulas for practically estimating the allowable demand or the required capacity to fulfill any design objective. Copyright © 2012 John Wiley & Sons, Ltd.