1,721,001 research outputs found
Seismic Response of Isolated Bridges Accounting for Spatial Variability of Ground Motion
No full textModelli costitutivi inelastici con discontinuità forti per il calcestruzzo: formulazione teorica ed analisi numerica
No full textTesi di Dottorat
The Response of Isolated Bridges Accounting for Spatial Variability of Ground Motion
No full textThe effects of the spatial variability of ground motion (loss of coherence, wave passage, and local site conditions) on the response of isolated bridges are investigated. Therefore, a statistical approach is adopted to represent uncertainties in both the bridge configuration and the ground motion variability. The response of isolated bridges, designed for a standard input motion, under a spatially varying ground motion, is evaluated by nonlinear time-history analyses; the system performance is measured by the displacement demand on isolators. Results show that the phenomenon affects the structural response considerably; the demand increases for the majority of isolators, irrespective of bridge configuration
Probabilistic seismic assessment of health-care systems at regional scale
No full textThis paper presents a model to estimate the impact of an earthquake on the regional health-care system and to evaluate its capability to cope with the demand of medical care arising from a seismic event. The probabilistic methodology recently developed for the seismic assessment of a single hospital facility (Lupoi et al., 2008), whose performance is measured in terms of the number of functioning operating theatres and of beds available, is integrated in this work within a larger analysis framework for the seismic vulnerability assessment of interconnected infrastructural systems, designed to account for interdependencies between transportation, utility networks and the buildings hit by a seismic event, as well as for all relevant uncertainties, especially in terms of distributed seismic hazard and physical vulnerability of the systems. The proposed model is applied to a sample infrastructure, made up of a regional health-care system and a road network
Valutazione e consolidamento sismico dei ponti esistenti
No full textLo scopo del presente manuale è quello di fornire un aiuto per la valutazione dei ponti esistenti in accordo alle citate linee guida, il testo delle quali è presentato nel Capitolo 2. Per quanto riguarda il progetto dell’adeguamento, il capito 3 illustra i più frequenti tipi di interventi che si rendono necessari per correggere le deficienze rilevate nella valutazione. Il Capitolo 4 presenta tre esempi di applicazione delle linee guida a ponti con pile e fusto unico, sia nello stato di fatto che nell’ipotesi di allargamento. Completano il manuale due appendici che propongono metodi per trattare due aspetti più specialistici dell’analisi delle strutture da ponte: l’effetto del moto non-sincrono alla base delle pile e l’interazione, sia cinematica che inerziale, tra struttura e terreno
Seismic resilience of regional health-care systems
No full textThe seismic performance of a regional Health-Care System (HCS) is investigated.The earthquake effects both on hospitals and on the Road Network (RDN), connecting towns to hospitals, are evaluated and the interaction among them accounted for. Victims move to hospitals until their request for a bed or for a surgical treatment is satisfied, if possible. A novel "dynamic" model for hospitalization is developed end implemented. The road network is modelled in connectivity terms. The vulnerability of hospitals and bridges is expressed by pre-evaluated fragility curves. Seismic hazard is described by a state-of-the-art model. The reliability problem is solved by Monte Carlo simulation. The un-hospitalized victims, the hospital's risk of failure in providing medical care, the demand of medical care on hospitals, the hospitalization travel time are among the useful results available from the analysis. The methodology is exemplified with reference to a case-study region, with population of 877,000, 20 towns, 5 hospitals and 32 bridges. © 2013 Taylor & Francis Group, London
Methods of seismic risk analysis: State-of-the-Art versus advanced State-of-the-Practice
No full textThe core of the paper consists of the illustration of a method for seismic reliability analysis of non-linear structures. The method, which is a development over a recent previous proposal, is quite comprehensive in scope since it includes consideration of randomness in the input, in the mechanical properties of the structure and in the limit-state, or capacity, conditions. Essentially, the problem is formulated as the out-crossing of the response process out of a (scalar) safe threshold, and this problem is solved by time-invariant FORM methods. An application to an idealised five-storey building demonstrates the salient theoretical and computational features of the method. The new approach is presented in a broader framework, which involves a discussion on present trends and capabilities in the area of probabilistic seismic design. For the sake of this discussion, two approaches just appeared in the literature are outlined, which are less demanding from a theoretical standpoint, and hence closer to engineering practice, but also less general in scope. It is argued that their introduction on code-assisted design would be feasible immediately with obvious advantages, while approaches of more rigorous nature would be given some more time to mature and to become more accessible to professional use
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