Investigation of the effect of ground motion parameters on the seismic vulnerability of structures

Καρδούτσου, Βασιλική; Kardoutsou, Vassiliki

dc.contributor.author	Καρδούτσου, Βασιλική	el
dc.contributor.author	Kardoutsou, Vassiliki	en
dc.date.accessioned	2020-07-24T06:25:58Z
dc.date.available	2020-07-24T06:25:58Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/50956
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.18654
dc.rights	Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/gr/	*
dc.subject	Εδαφική	el
dc.subject	Κίνηση	el
dc.subject	Κατευθυντικότητα	el
dc.subject	Τρωτότητα	el
dc.subject	Παλμός	el
dc.subject	Ground	en
dc.subject	motion	en
dc.subject	Directivity	en
dc.subject	Pulse	en
dc.subject	Vulnerability	en
dc.title	Investigation of the effect of ground motion parameters on the seismic vulnerability of structures	en
dc.title	Δείκτες Παραμετροποίησης της Εδαφικής Κίνησης για την Ανάλυση της Σεισμικής Τρωτότητας των Κατασκευών	el
dc.contributor.department	Εργαστήριο Αντισεισμικής Τεχνολογίας	el
heal.type	doctoralThesis
heal.classification	Τεχνική Σεισμολογία	el
heal.language	en
heal.access	campus
heal.recordProvider	ntua	el
heal.publicationDate	2019-11-13
heal.abstract	Pulse-like seismic records constitute a special category of ground motions due to their effect on the demand on structures. The pulses inherent in these motions are mainly produced by near-field directivity effects and. Up to now, the classification of a record as pulse-like has been based on the assumption that the pulse portion of the ground motion contains a significant amount of the total energy. Different approaches are presented and evaluated in this thesis based on the value of the recently introduced parameter CAD (Cumulative Absolute Displacement), defined as the integral of the absolute ground velocity, compared with the spectral displacement for zero damping SD0%(Tp), associated with the characteristic period Tp of the inherent pulse, and the cross correlation of the significant pulse and the original record. It is proven that, for pulse-like ground motions, the ratio SD0%(Tp)/CAD is around π/4, where for non pulse-like ground motions the value of the ratio is much lower. A second important pulse indicator PI for the characterization of seismic motions as pulse-like or non pulse-like is set equal to the cross correlation factor of the significant pulse and the original record. It is suggested that records for which PI is larger than 0.65 are characterized as pulse-like, while records with PI less than 0.55 are characterized as non pulse-like. The proposed classification was checked against the inelastic response of SDOF structures. To this end, the inelastic displacement of SDOF systems with period equal to half the pulse period and reduction factor R = 4 are computed for 124 records. Records having values of PI larger than 0.65, which are classified as pulse-like, produce larger ductility demands as the majority of ratio values are larger than 1.5. On the other hand, records having values of PI lower than 0.55, which are classified as non pulse-like, present ratios lower than 1.5 with an average value around unity. It is seen that the two previous methods ignore some records with large inelastic demands. As far as the strong ground motion content is equal to the integral of the absolute ground velocity of the record, for a time interval between the first and the last crossing of the threshold amplitude of 70% of peak ground velocity, the index given as CAD-70% was finally determined after various approximations. An example of the effect on the inelastic demand on structures is performed for a SDOF. An investigation is presented concerning the effect of the directivity pulses inherent in near-fault ground motions on the inelastic response of a curved RC bridge, specifically Bridge G7 of Egnatia Highway in Greece. The analyses were performed for a sample of 90 near-fault seismic records. From each record, the first six pulses were extracted and simplified ‘pulse records’ were defined, composed of one or more (up to six) pulses. The results show that the maximum inelastic deformations occur for the ground motions for which the elastic fundamental period of the bridge is close to one half of the period of the predominant pulse. Also, in most cases, the maximum response for the original record could be adequately estimated by the response for the ‘pulse record’ consisted of only two (and in few cases of three) pulses, especially when the fundamental period of the bridge was in between the periods of these pulses. It is obvious from the above that the determination of the strong directivity pulse should be determined. The normal-to-the fault component is assumed to contain the strongest directivity pulse, an assumption that in most cases is only approximately true, while there are cases in which the two directions diverge significantly. In this theses, the direction of the strong component of near fault ground motions is investigated with respect to the orientation of the fault, the fault type, the closest distance to the fault and the soil type. It is shown that the strong component can be determined by the maximum value of the energy content and that, in general, it does not coincide with the fault normal direction, also depending on the fault type. Finally, an attempt is made to determine the relation of a pulse period with seismic parameters. A statistical analysis of the pulse period in relation with several seismological parameters is performed herein. The set of records from the NGA database that have been characterized as pulse-like is used for a statistical investigation of the relation of the pulse period with three strong-motion parameters, namely the magnitude of the event, the closest distance to the fault and the soil type using the shear wave velocity, which resulted in a new empirical relationship for the estimation of the pulse period Tp.	en
heal.sponsor	The author wants to thank the Greek State Scholarships Foundation for the financial support of her postgraduate studies at NTUA through “IKY Fellowships of excellence for postgraduate studies in Greece – Siemens program”.	en
heal.advisorName	Ψυχάρης, Ιωάννης	el
heal.advisorName	Μουζάκης, Χαράλαμπος	el
heal.advisorName	Μπουκοβάλας, Γεώργιος	el
heal.committeeMemberName	Ψυχάρης, Ιωάννης	el
heal.committeeMemberName	Μουζάκης, Χαράλαμπος	el
heal.committeeMemberName	Μπουκοβάλας, Γεώργιος	el
heal.committeeMemberName	Γκαζέτας, Γεώργιος	el
heal.committeeMemberName	Γαντές, Χαράλαμπος	el
heal.committeeMemberName	Μαυροειδής, Γεώργιος	el
heal.committeeMemberName	Σέξτος, Αναστάσιος	el
heal.academicPublisher	Σχολή Πολιτικών Μηχανικών	el
heal.academicPublisherID	ntua
heal.numberOfPages	174
heal.fullTextAvailability	true