Ductile Seismic Design, Performance Assessment and Taxonomic Characterization of Steel Racking Systems

Τσαρπαλής, Δημήτριος; Tsarpalis, Dimitrios

dc.contributor.author	Τσαρπαλής, Δημήτριος	el
dc.contributor.author	Tsarpalis, Dimitrios	en
dc.date.accessioned	2022-10-13T07:45:58Z
dc.date.available	2022-10-13T07:45:58Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/55902
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.23600
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	Racking systems	en
dc.subject	Content sliding	en
dc.subject	Rack taxonomy	en
dc.subject	Ductile seismic design	en
dc.subject	Seismic assessment	en
dc.subject	Συστήματα ραφιών	el
dc.subject	Ολίσθηση περιεχομένων	el
dc.subject	Ταξινομία ραφιών	el
dc.subject	Σεισμική αποτίμηση	el
dc.subject	Πλάστιμος σεισμικός σχεδιασμός	el
dc.title	Ductile Seismic Design, Performance Assessment and Taxonomic Characterization of Steel Racking Systems	en
dc.title	Πλάστιμος Σεισμικός Σχεδιασμός, Αποτίμηση Επιτελεστικότητας και Ταξινομικός Χαρακτηρισμός Συστημάτων Μεταλλικών Ραφιών	el
dc.contributor.department	Τομέας Δομοστατικής - Εργαστήριο Μεταλλικών Κατασκευών	el
heal.type	doctoralThesis
heal.classification	Steel structures	en
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2022-05-23
heal.abstract	Steel racking systems are Civil Engineering structures used to store the goods and materials of a warehousing unit. In order to facilitate the construction process and to minimize the weight of the steel members, racks are characterized by a number of peculiarities that distinguish them from ordinary buildings. Due to their loose connections and lightness, racks are flexible structures, characterized by significant geometric nonlinearities and local buckling phenomena that significantly deteriorate their lateral-loading response. Indeed, past earthquake events have revealed the vulnerability of racks against strong ground motions, underlining the need for novel design approaches in order to increase their resilience. Research so far has focused on understanding the cyclic behaviour of members and joints that belong to the most common rack configuration, namely adjustable pallet racking systems. However, in order to serve different logistic needs, a variety of rack typologies with different uses and salient characteristics has evolved over time. As a result, racks can range from large independent buildings in the form of the automated rack supported warehouses (ARSWs), down to compact sub-structures. Along these lines, the macro-characteristics of various rack typologies are discussed for the first time, identifying their idiosyncrasies and commonalities to other systems, which are then summarized in a flexible and collapsible taxonomy. In view of better understanding the behaviour of ARSWs to earthquake excitations, a comprehensive seismic assessment is conducted on five multi-depth case studies, designed by professional engineers according to the current European standards. The impact of the design assumptions on the definition of the seismic loads is highlighted and aggregated in a cumulative seismic load multiplier. Consequently, a series of linear response history analyses is performed, in order to assess the vulnerability of the ARSWs to non-ductile failure modes and to define a hierarchy of criticalities for each case study. Following the current tendency in the earthquake engineering community for resilient infrastructure, a ductile seismic design framework is proposed for the cross-aisle direction of racks, so-called plastic ovalization strategy (POS). POS relies on the bearing deformation of the diagonal bolt hole to introduce ductility and reduce seismic demands, employing capacity design to avoid non-ductile failure modes. Analytical equations and finite element models are used to determine the key factors that influence the ductility of the connection and to calibrate the uniaxial springs in a beam element model. Finally, to assess the performance of POS, two ARSWs are examined. To achieve frugal performance assessment of racking systems, a reduced-order modelling approach is proposed that replaces the entire cross-aisle frame with a single/double built-up column, equivalent Timoshenko beams or link elements. The resulting model can support 2D/3D elastic and inelastic analyses, allowing rapid structural analysis of massive racking systems. Finally, the dissertation attempts to fill a gap in the problem of content-structure-sliding interaction (CSSI), a multi-faceted phenomenon that offers both detrimental and beneficial effects to the racking structure. Three approaches are investigated to capture CSSI, each characterized by its own modelling needs and level of accuracy. Simplified alternatives are calibrated using single degree of freedom systems and realistic rack case studies, offering a reliable tool for structural engineers to (a) accurately determine the expected pallet sliding displacements, and (b) correctly reduce the design seismic loads thanks the seismic isolation mechanism offered by CSSI.	en
heal.sponsor	This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning» in the context of the project “Strengthening Human Resources Research Potential via Doctorate Research” (MIS-5000432), implemented by the State Scholarships Foundation (ΙΚΥ).	en
heal.advisorName	Βάγιας, Ιωάννης	el
heal.advisorName	Vayas, Ioannis	en
heal.committeeMemberName	Vayas, Ioannis
heal.committeeMemberName	Vamvatsikos, Dimitrios
heal.committeeMemberName	Thanopoulos, Pavlos
heal.committeeMemberName	Gantes, Charis
heal.committeeMemberName	Avraam, Anastasios
heal.committeeMemberName	Morelli, Francesco
heal.committeeMemberName	Castiglioni, Carlo Andrea
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Πολιτικών Μηχανικών	el
heal.academicPublisherID	ntua
heal.numberOfPages	207
heal.fullTextAvailability	false