Near-optimal bilinear fit of 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	2014-03-01T02:53:22Z
dc.date.available	2014-03-01T02:53:22Z
dc.date.issued	2011	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/36271
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-80054795417&partnerID=40&md5=778973814731b646bf48d733572fff0c	en
dc.subject	Bilinearization	en
dc.subject	Equivalent SDOF	en
dc.subject	Incremental dynamic analysis	en
dc.subject	Static pushover	en
dc.subject.other	Assessment procedure	en
dc.subject.other	Bilinear approximation	en
dc.subject.other	Bilinearization	en
dc.subject.other	Capacity curves	en
dc.subject.other	Collapse mechanism	en
dc.subject.other	Equivalent SDOF	en
dc.subject.other	Incremental dynamic analysis	en
dc.subject.other	Multi-degree-of-freedom	en
dc.subject.other	Nonlinear statics	en
dc.subject.other	Piecewise linear approximations	en
dc.subject.other	Seismic Performance	en
dc.subject.other	Single-degree-of-freedom	en
dc.subject.other	Spectral acceleration	en
dc.subject.other	Static pushover	en
dc.subject.other	Structural models	en
dc.subject.other	Structural systems	en
dc.subject.other	Civil engineering	en
dc.subject.other	Computational methods	en
dc.subject.other	Curve fitting	en
dc.subject.other	Deformation	en
dc.subject.other	Dynamic analysis	en
dc.subject.other	Earthquakes	en
dc.subject.other	Engineering geology	en
dc.subject.other	Model structures	en
dc.subject.other	Optimization	en
dc.subject.other	Piecewise linear techniques	en
dc.subject.other	Stiffness	en
dc.subject.other	Structural dynamics	en
dc.subject.other	Structural analysis	en
dc.title	Near-optimal bilinear fit of capacity curves for equivalent sdof analysis	en
heal.type	conferenceItem	en
heal.publicationDate	2011	en
heal.abstract	The bilinear approximation of force-deformation capacity curves is investigated for structural systems with non-negative-stiffness. This piecewise linear approximation process factually links capacity and demand; it lies at the core of the nonlinear static assessment procedures, and it has become part of seismic guidelines and codes, such as ASCE-41 and Euro-code 8. Despite codification, the various fitting rules, used to derive the bilinear representation, can produce highly heterogeneous results for the same capacity curve. This is especially valid for highly-curved backbones resulting from structural models with accurate representation of the initial, uncracked, stiffness or buildings characterized by a global collapse mechanism that leads to a gradual plasticization of the elements. The error introduced by the bilinearization of the force-deformation relationship is quantified by studying it at the single-degree-of-freedom (SDOF) level, away from any interference from multi-degree-of-freedom (MDOF) effects, thus avoiding the issue related to MDOF - SDOF approximation. Incremental Dynamic Analysis (IDA) is employed to enable a direct comparison of the actual backbones versus their bilinear approximations in terms of the spectral acceleration capacity for a continuum of limit-states, allowing a direct comparison of the results in terms of seismic performance. Code-based procedures are found to be less than ideal wherever there are significant stiffness changes, while in general remaining relatively conservative. The practical fitting rules determined allow, instead, a near-optimal fit regardless of the details of the capacity curve shape.	en
heal.journalName	ECCOMAS Thematic Conference - COMPDYN 2011: 3rd International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering: An IACM Special Interest Conference, Programme	en