Shakeel, Sarmad (2020) In plane seismic performance assessment of Lightweight Steel Walls used for Structural and Non-structural applications. [Tesi di dottorato]
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Testo
SarmadThesisDIST.pdf Download (17MB) | Anteprima |
| Tipologia del documento: | Tesi di dottorato | ||||||
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| Lingua: | English | ||||||
| Titolo: | In plane seismic performance assessment of Lightweight Steel Walls used for Structural and Non-structural applications | ||||||
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| Data: | 3 Marzo 2020 | ||||||
| Numero di pagine: | 424 | ||||||
| Istituzione: | Università degli Studi di Napoli Federico II | ||||||
| Dipartimento: | Strutture per l'Ingegneria e l'Architettura | ||||||
| Dottorato: | Ingegneria strutturale, geotecnica e rischio sismico | ||||||
| Ciclo di dottorato: | 32 | ||||||
| Coordinatore del Corso di dottorato: |
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| Tutor: |
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| Data: | 3 Marzo 2020 | ||||||
| Numero di pagine: | 424 | ||||||
| Parole chiave: | Colf-formed steel, seismic, walls | ||||||
| Settori scientifico-disciplinari del MIUR: | Area 08 - Ingegneria civile e Architettura > ICAR/08 - Scienza delle costruzioni Area 08 - Ingegneria civile e Architettura > ICAR/09 - Tecnica delle costruzioni Area 08 - Ingegneria civile e Architettura > ICAR/17 - Disegno |
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| Depositato il: | 19 Mar 2020 07:46 | ||||||
| Ultima modifica: | 06 Apr 2022 10:00 | ||||||
| URI: | http://www.fedoa.unina.it/id/eprint/13001 |
Abstract
The European earthquake design standard: Eurocode 8 does not address the seismic design of lightweight steel (LWS) buildings. This has limited the use of LWS buildings in the earthquake prone regions of the European continent, where Eurocodes are enforced by law as the mandatory design reference documents. Moreover, architectural non-structural building components made with the LWS framing are also finding it hard to penetrate in the building markets of such regions due to the absence of the documented data on their seismic performance. In this context, the main objective of the research presented in this thesis is to develop a scientific database to assist engineers in achieving a rational performance based seismic design (PBSD) of LWS buildings. The scientific database includes the numerical and statistical tools for estimating the in plane seismic performance of LWS walls and a set of seismic design guidelines that can be proposed for the inclusion in the next edition of Eurocodes. Different objectives have been pursued for the structural components, which include the lateral force resisting systems (LFRS) for providing the earthquake resistance in the LWS buildings i.e. strap braced and shear walls and for the non-structural architectural LWS components i.e. partition walls and façades. The approach for the structural components involves the checking of collapse fragility of strap-braced and shear walls using the iterative procedures of FEMA P695, while the approach for non-structural architectural components focuses on developing the numerical models for the most widely used architectural components: partition walls and façades assisted with an extensive experimental campaign. Behaviour factor for the two most commonly used LWS LFRS systems: CFS strap braced walls and CFS shear walls with gypsum or wood sheathing is evaluated through FEMA P695 methodology. For each type of system, a set of archetypes, which represent a range of design parameters and building configurations is designed following the capacity design approach and their response is idealized by nonlinear models in OpenSees software. The performance of archetype models is evaluated systematically through the static pushover and the incremental dynamic analysis under a suite of forty-four normalized and scaled earthquake records, representing the probable seismic hazard to the buildings. Finally, by calculating the collapse probability while also considering the uncertainties from various sources, the suitability of trial value of behaviour factor used in the design phase of archetypes is evaluated. Based on the results, it is concluded that a behaviour factor of 2.5, 2.0 and 2.5 for CFS strap-braced walls, CFS gypsum sheathed shear walls and CFS wood sheathed shear walls is appropriate. Seismic performance of infilled façades made of LWS drywall systems is investigated via in plane quasi-static cyclic tests on eight different configurations of façades. Eight specimens are built following the common European construction practices and are infilled in a steel pendulum structure. The specimens differ from each other in terms of construction details: dual or single metal framed façades; types of boards used on different faces of the façades; presence of the cladding; fixed or sliding connections to the surrounding structural elements; profile dimensions of the frame elements. The effect of these construction details is examined through the comparison of strength and secant stiffness of the tested specimens. The main types of damages observed during the tests are examined and associated to three damage limit states. Subsequently, fragility curves are developed for the assessment of seismic fragility of the tested façades and compliance is checked with the inter storey drift limits for architectural non-structural elements required by Eurocode 8. Finally, a set of simplified numerical models are proposed for LWS indoor partition walls, to simulate their in-plane seismic response, that can be easily integrated with the building models and possess the ability to better estimate damages in them, when linked to their fragility information. The models are developed in OpenSees software by using a single discretized spring to simulate the lumped behavior of the walls for the twelve individual different configurations of the tested partitions. The accuracy of model is demonstrated by comparing the experimental and the numerical results in terms of the hysteretic response curves and the cumulative energy dissipated.
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