11 research outputs found
Modelli digitali 3D per documentare, conoscere ed analizzare l’architettura e la costruzione nel mondo antico: l’esempio della Sala Ottagonale delle Piccole Terme di Villa Adriana
For its unique features and size, the Hadrian’s Villa site has always been the object of studies and investigations. Italian and foreign institutions, as well as research organizations, are working together with the common purpose of understanding and protecting the universally recognized ensemble of buildings and works of art, belonging to the World Heritage List since 1999. Within this interdisciplinary framework, over the past decade, new technologies for digital documentation in the field of cultural heritage have gained more importance with respect to the traditional field of architectural/archaeological surveying. Through expeditious surveying (with no physical contact with the object and different measurement resolutions) several 3D reality-based models were created in the last years, with special regards to the Villa’s pavilions characterized by more complex and daring shapes. The aim was a better understanding of specific problems in those cases where archaeological investigation methods may take advantage of a correct and complete digital surveying of elevations in general and in particular of vaulted spaces, intrados and extrados surfaces. 3D digital models of complex roofing, as shown in the case study of the Small Baths, provide additional advantages concerning the use of finite elements analysis (FEA). Both the digital models (current state of conservation and reconstruction hypothesis) underwent to an accurate stress analysis that enables further achievements for site conservation and management and for ancient constructive and designing techniques
Ductility of wide-beam RC frames as lateral resisting system
[EN] Some Mediterranean seismic codes consider wide-beam reinforced concrete moment resisting frames (WBF) as horizontal load carrying systems that cannot guarantee high ductility performances. Conversely, Eurocode 8 allows High Ductility Class (DCH) design for such structural systems. Code prescriptions related to WBF are systematically investigated. In particular, lesson learnt for previous earthquakes, historical reasons, and experimental and numerical studies underpinning specific prescriptions on wide beams in worldwide seismic codes are discussed. Local and global ductility of WBF are then analytically investigated through (1) a parametric study on chord rotations of wide beams with respect to that of deep beams, and (2) a spectral-based comparison of WBF with conventional reinforced concrete moment resisting frames (i.e. with deep beams). Results show that the set of prescriptions given by modern seismic codes provides sufficient ductility to WBF designed in DCH. In fact, global capacity of WBF relies more on the lateral stiffness of the frames and on the overstrength of columns rather than on the local ductility of wide beams, which is systematically lower with respect to that of deep beams.Gómez-Martínez, F.; Alonso Durá, A.; De Luca, F.; Verderame, GM. (2016). Ductility of wide-beam RC frames as lateral resisting system. Bulletin of Earthquake Engineering. 14(6):1545-1569. doi:10.1007/s10518-016-9891-xS15451569146ACI (1989) Building code requirements for reinforced concrete (ACI 318-89). ACI Committee 318, American Concrete Institute, Farmington Hills, Michigan, USAACI (2008) Building code requirements for structural concrete (ACI 318-08) and commentary (318-08). ACI Committee 318, American Concrete Institute, Farmington Hills, Michigan, USAACI-ASCE (1991) Recommendations for design of beam-column connections in monolithic reinforced concrete structures (ACI 352R-91). Joint ACI-ASCE Committee 352, American Concrete Institute, Farmington Hills, Michigan, USAACI-ASCE (2002) Recommendations for design of beam-column connections in monolithic reinforced concrete structures (ACI 352R-02). Joint ACI-ASCE Committee 352, American Concrete Institute, Farmington Hills, Michigan, USAArslan MH, Korkmaz HH (2007) What is to be learned from damage and failure of reinforced concrete structures during recent earthquakes in Turkey? Eng Fail Anal 14(1):1–22ASCE (2007) Seismic Rehabilitation of Existing Buildings, ASCE/SEI 41-06. American Society of Civil Engineers, RestonASCE (2010) Minimum Design Loads for Building and Other Structures, ASCE/SEI 7-10. American Society of Civil Engineers, RestonBenavent-Climent A (2007) Seismic behavior of RC side beam-column connections under dynamic loading. J Earthquake Eng 11:493–511Benavent-Climent A, Zahran R (2010) An energy-based procedure for the assessment of seismic capacity of existing frames: application to RC wide beam systems in Spain. Soil Dyn Earthq Eng 30:354–367Benavent-Climent A, Cahís X, Zahran R (2009) Exterior wide beam-column connections in existing RC frames subjected to lateral earthquake loads. Eng Struct 31:1414–1424Benavent-Climent A, Cahís X, Vico JM (2010) Interior wide beam-column connections in existing RC frames subjected to lateral earthquake loading. Bull Earthq Eng 8:401–420BHRC (2004) Iranian Code of Practice for Seismic Resistant Design of Buildings. Standard Nº 2800, 3rd edn. Building and Housing Research Center, TehranBorzi B, Elnashai AS (2000) Refined force reduction factors for seismic design. Eng Struct 22:1244–1260Borzi B, Pinho R, Crowley H (2008) Simplified pushover-based vulnerability analysis for large-scale assessment of RC buildings. 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European Standard EN 1998-1:2005—Comité Européen de Normalisation, Brussels, BelgiumCheung PC, Paulay T, Park R (1991) Mechanisms of slab contributions in beam-column subassemblages. ACI Spec Publ 123Cosenza E, Manfredi G, Polese M, Verderame GM (2005) A multilevel approach to the capacity assessment of existing RC buildings. J Earthquake Eng 9(1):1–22Crowley H, Pinho R (2010) Revisiting Eurocode 8 formulae for periods of vibration and their employment in linear seismic analysis. Earthquake Eng Struct Dynam 39:223–235CS.LL.PP (2009) Instructions for the application of the technique code for the Constructions. Official Gazette of the Italian Republic, 47, Regular Supplement no. 27 (in Italian)De Luca F, Vamvatsikos D, Iervolino I (2013) Near-optimal piecewise linear fits of static pushover capacity curves for equivalent SDOF analysis. Earthquake Eng Struct Dynam 42(4):523–543De Luca F, Verderame GM, Gómez-Martínez F, Pérez-García A (2014) The structural role played by masonry infills on RC building performances after the 2011 Lorca, Spain, earthquake. Bull Earthq Eng 12(5):1999–2026Decanini LD, Mollaioli F (2000) Analisi di vulnerabilità sismica di edifici in cemento armato pre-normativa. In: Cosenza E (ed) Comportamento sismico di edifici in cemento armato progettati per carichi verticali. CNR—Gruppo Nazionale per la Difesa dei Terremoti, Rome (in Italian)Dolšek M, Fajfar P (2004) IN2—a simple alternative for IDA. In: Proceedings of the 13th World conference on Earthquake Engineering. August 1–6, Vancouver, Canada. Paper 3353Domínguez D, López-Almansa F, Benavent-Climent A (2014) Comportamiento para el terremoto de Lorca de 11-05-2011, de edificios de vigas planas proyectados sin tener en cuenta la acción sísmica. Informes de la Construcción 66(533):e008 (in Spanish)Domínguez D, López-Almansa F, Benavent-Climent A (2016) Would RC wide-beam buildings in Spain have survived Lorca earthquake (11-05-2011)? Eng Struct 108:134–154Dönmez C (2013) Seismic Performance of Wide-Beam Infill-Joist Block RC Frames in Turkey. J Perform Constr Facil 29(1):04014026Fadwa I, Ali TA, Nazih E, Sara M (2014) Reinforced concrete wide and conventional beam-column connections subjected to lateral load. Eng Struct 76:34–48Fardis MN (2009) Seismic design, assessment and retrofitting of concrete, Buildings edn. Springer, LondonGentry TR, Wight JK (1992) Reinforced concrete wide beam-column connections under earthquake-type loading. Report no. UMCEE 92-12. Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USAGómez-Martínez F (2015) FAST simplified vulnerability approach for seismic assessment of infilled RC MRF buildings and its application to the 2011 Lorca (Spain) earthquake. Ph.D. Thesis, Polytechnic University of Valencia, SpainGómez-Martínez F, Pérez García A, De Luca F, Verderame GM (2015a) Comportamiento de los edificios de HA con tabiquería durante el sismo de Lorca de 2011: aplicación del método FAST. Informes de la Construcción 67(537):e065 (in Spanish)Gómez-Martínez F, Pérez-García A, Alonso Durá A, Martínez Boquera A, Verderame GM (2015b) Eficacia de la norma NCSE-02 a la luz de los daños e intervenciones tras el sismo de Lorca de 2011. In: Proceedings of Congreso Internacional sobre Intervención en Obras Arquitectónicas tras Sismo: L’Aquila (2009), Lorca (2011) y Emilia Romagna (2012), May 13–14, Murcia, Spain (in Spanish)Gómez-Martínez F, Verderame GM, De Luca F, Pérez-García A, Alonso-Durá, A (2015c). High ductility seismic performances of wide-beam RC frames. In; XVI Convegno ANIDIS. September 13–17, L'Aquila, ItalyHawkins NM, Mitchell D (1979) Progressive collapse of flat plate structures. 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Padova, ItalyMazzolani FM, Piluso V (1997) Plastic design of seismic resistant steel frames. Earthquake Eng Struct Dynam 26:167–191MEPP (2000a) Greek earthquake resistant design code, EAK 2000. Ministry of Environment, Planning and Public Works, AthensMEPP (2000b) Greek code for the design and construction of concrete works, EKOS 2000. Ministry of Environment, Planning and Public Works, Athens (in Greek)Miranda E, Bertero VV (1994) Evaluation of strength reduction factors for earthquake-resistant design. Earthq Spectra 10(2):357–379MPWS (2007) Specifications for buildings to be built in seismic areas. Turkish Standards Institution, Ministry of Public Works and Settlement, Ankara (in Turkish)Mwafy AM, Elnashai AS (2002) Calibration of force reduction factors of RC buildings. J Earthquake Eng 6(2):239–273NZS (2004) Structural design actions. Part 5: earthquake actions, NZS 1170.5. 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Effects on short term outcome of non-invasive ventilation use in the emergency department to treat patients with acute heart failure: A propensity score-based analysis of the EAHFE Registry
Objective: To assess the effects of non-invasive ventilation (NIV) in emergency department (ED) patients with acute heart failure (AHF) on short term outcomes.
Methods: Patients from the EAHFE Registry (a multicenter, observational, multipurpose, cohort-designed database including consecutive AHF patients in 41 Spanish EDs) were grouped based on NIV treatment (NIV+ and NIV–groups). Using propensity score (PS) methodology, we identified two subgroups of patients matched by 38 covariates and compared regarding 30-day survival (primary outcome). Interaction was investigated for age, sex, ischemic cardiomyopathy, chronic obstructive pulmonary disease, AHF precipitated by an acute coronary syndrome (ACS), AHF classified as hypertensive or acute pulmonary edema (APE), and systolic blood pressure (SBP). Secondary outcomes were intensive care unit (ICU) admission; mechanical ventilation; in-hospital, 3-day and 7-day mortality; and prolonged hospitalization (>7 days).
Results: Of 11, 152 patients from the EAHFE (age (SD): 80 (10) years; 55.5% women), 718 (6.4%) were NIV+ and had a higher 30-day mortality (HR = 2.229; 95%CI = 1.861–2.670) (p 85 years, p < 0.001), AHF associated with ACS (p = 0.045), and SBP < 100 mmHg (p < 0.001). No significant differences were found in the secondary endpoints except for more prolonged hospitalizations in NIV+ patients (OR = 1.445; 95%CI = 1.122–1.862) (p = 0.004).
Conclusion: The use of NIV to treat AHF in ED is not associated with improved mortality outcomes and should be cautious in old patients and those with ACS and hypotension
Influence of the length of hospitalisation in post-discharge outcomes in patients with acute heart failure: Results of the LOHRCA study
Objective: To investigate the relationship between length of hospitalisation (LOH) and post-discharge outcomes in acute heart failure (AHF) patients and to ascertain whether there are different patterns according to department of initial hospitalisation.
Methods: Consecutive AHF patients hospitalised in 41 Spanish centres were grouped based on the LOH (15 days). Outcomes were defined as 90-day post-discharge all-cause mortality, AHF readmissions, and the combination of both. Hazard ratios (HRs), adjusted by chronic conditions and severity of decompensation, were calculated for groups with LOH >6 days vs. LOH <6 days (reference), and stratified by hospitalisation in cardiology, internal medicine, geriatrics, or short-stay units.
Results: We included 8563 patients (mean age: 80 (SD = 10) years, 55.5% women), with a median LOH of 7 days (IQR 4–11): 2934 (34.3%) had a LOH 15 days. The 90-day post-discharge mortality was 11.4%, readmission 32.2%, and combined endpoint 37.4%. Mortality was increased by 36.5% (95%CI = 13.0–64.9) when LOH was 11–15 days, and by 72.0% (95%CI = 42.6–107.5) when >15 days. Conversely, no differences were found in readmission risk, and the combined endpoint only increased 21.6% (95%CI = 8.4–36.4) for LOH >15 days. Stratified analysis by hospitalisation departments rendered similar post-discharge outcomes, with all exhibiting increased mortality for LOH >15 days and no significant increments in readmission risk.
Conclusions: Short hospitalisations are not associated with worse outcomes. While post-discharge readmissions are not affected by LOH, mortality risk increases as the LOH lengthens. These findings were similar across hospitalisation departments
El significado funcional de los cíngulos anterior y posterior en el rinoceronte Alicornops simorrense (Lartet, 1851) mediante el análisis de elementos finitos
El análisis de elementos finitos (AEF) es un método numérico desarrollado originalmente para simular la respuesta mecánica de fuerzas discretas aplicadas sobre estructuras complejas. Se pretende analizar el papel de los cíngulos anterior y posterior en el proceso de masticación en rinocerontes. Se ha utilizado un modelo 3D simplificado de un molar genérico de rinoceronte obtenido a partir de un MI superior del rinoceronte Alícornops símorrense procedente de Nombrevilla (Zaragoza). Los resultados muestran una mayor concentración de tensiones alrededor del valle central y, en menor medida, una disminución de las mismas en el ectolofo del modelo con cíngulos. El molar con cíngulos también muestra una mayor resistencia a la deformación producida por las fuerzas de masticación.Peer Reviewe
Inelastic deformations of wide beams and deep beams
Current formulations proposed by Eurocode 8 part 3 for the inelastic deformations of existing reinforced concrete members are assessed aimed at finding out whether they are representative of beams with different cross-sectional aspect ratio, in particular for wide beams (WB) contrasted with conventional deep beams (DB). The current approach shows that WB present larger ultimate chord rotation but lower chord rotation ductility than DB despite the similar curvature ductilities, due to lower plastic hinge lengths in WB. Results of the large experimental database on the basis of current model are disaggregated for DB and WB. Predicted chord rotations appear to be significantly biased for both types, especially at ultimate; the actual model provides conservative values for DB and non-conservative values for WB, which suggest that plastic hinge length may be even greater for DB in comparison to WB. Hence, some different feasible modifications of both pure empirical and fundamental formulations for chord rotations are proposed, in order to reduce the bias and thus increasing the robustness of the model against cross-sectional shape variability
Eficacia de la norma NCSE-02 a la luz de los daños e intervenciones tras el sismo de Lorca de 2011
High ductility seismic performances of wide-beam RC frames
Italian and Spanish seismic codes, conversely to Eurocode 8 and other relevant seismic codes worldwide, consider that wide-beam RC frames (WBF) cannot guarantee high ductility performances, thus they compel to adopt lower behaviour factors (q) than for conventional deep-beam frames (DBF). The reason may be the poorer local ductility of wide beams with respect to deep beams, together with an historical lack of confidence on WBF regarding force transfer within connections and higher lateral deformability. Aimed at verifying the appropriateness of such provisions, seismic performances of a typical Mediterranean 5-storey RC building designed alternatively with DBF and WBF according to Eurocode 8 and Spanish NCSE-02 are comparatively assessed through nonlinear static analyses. Later, a simplified parametric assessment is carried out for 72 frames designed to Eurocode 8, Italian NTC and NCSE-02 assuming similar q for WBF and DBF. Results suggest that WBF provide at least similar global seismic capacities than DBF, especially in frames whose design is ruled by damage limitation limit state. Hence, any reduction of qfor wide-beam frames in modern national codes appears to be at least obsolete