Near-optimal piecewise linear fits of static pushover capacity curves for equivalent SDOF analysis

De Luca, F; Vamvatsikos, D; Iervolino, I

dc.contributor.author	De Luca, F	en
dc.contributor.author	Vamvatsikos, D	en
dc.contributor.author	Iervolino, I	en
dc.date.accessioned	2014-03-01T02:11:30Z
dc.date.available	2014-03-01T02:11:30Z
dc.date.issued	2012	en
dc.identifier.issn	00988847	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29923
dc.subject	Equivalent SDOF	en
dc.subject	Incremental dynamic analysis	en
dc.subject	Piecewise linear fit	en
dc.subject	Static pushover	en
dc.title	Near-optimal piecewise linear fits of static pushover capacity curves for equivalent SDOF analysis	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/eqe.2225	en
heal.identifier.secondary	http://dx.doi.org/10.1002/eqe.2225	en
heal.publicationDate	2012	en
heal.abstract	The piecewise linear ('multilinear') approximation of realistic force-deformation capacity curves is investigated for structural systems incorporating generalized plastic, hardening, and negative stiffness behaviors. This fitting process factually links capacity and demand and lies at the core of nonlinear static assessment procedures. Despite codification, the various fitting rules used can produce highly heterogeneous results for the same capacity curve, especially for the highly-curved backbones resulting from the gradual plasticization or the progressive failures of structural elements. To achieve an improved fit, the error introduced by the approximation is quantified by studying it at the single-degree-of-freedom level, thus avoiding any issues related to multi-degree-of-freedom versus single-degree-of-freedom realizations. Incremental dynamic analysis is employed to enable a direct comparison of the actual backbones versus their candidate piecewise linear approximations in terms of the spectral acceleration capacity for a continuum of limit-states. In all cases, current code-based procedures are found to be highly biased wherever widespread significant stiffness changes occur, generally leading to very conservative estimates of performance. The practical rules determined allow, instead, the definition of standardized low-bias bilinear, trilinear, or quadrilinear approximations, regardless of the details of the capacity curve shape. © 2012 John Wiley & Sons, Ltd.	en
heal.journalName	Earthquake Engineering and Structural Dynamics	en
dc.identifier.doi	10.1002/eqe.2225	en