Search results for "seismic"
showing 10 items of 338 documents
Genetic Optimization for the design of seismic retrofitting of plane RC frames with Buckling Restrained Braces (BRBs)
2021
The increasing development of computational power in modern digital devices has spread the use of structural optimization in design applications of different fields of engineering problems. This approach exposes engineers to challenging design procedures aimed to optimize all variables to satisfy the imposed requirements, finding the “optimal” solution. Despite this wide use, the application of optimization algorithms for the design of seismic retrofitting strategies becomes tougher, due to the difficulties in finding a mathematical expression which includes and combines all the key variables (i.e., cost, safety, sustainability, design) and the nonlinearity of the analysis. In this paper, t…
On the definition of seismic vulnerability maps in cross-border Mediterranean areas
2015
The chance to locate and quantify the major risks associated to natural catastrophic events on a territory allows to plan adequate strategies and interventions by civil protection bodies involved in local and international emergencies. The seismic risk depends most of all by the vulnerability of buildings belonging to the urban areas. For this reason the definition, by a deep analysis of the territory, of instruments identifying and locating vulnerability, largely favours the activities of institutions appointed to safeguard the safety of citizens. Seismic and hydro-geological risks constitute the major component of the activities involving assistance actions carried out by civil protection…
Numerical seismic performance of a rammed earth dwelling considering the use of a textile reinforced mortar system
Rammed earth buildings represent a considerable portion of the existing vernacular building stock of several countries and they are very common in the southern region of Portugal. The historical and architectural values of these constructions, along with their recognized high seismic vulnerability, have made the structural rehabilitation of earthen buildings a priority among the scientific community. Despite some recent studies, the prediction of the seismic response of these buildings is still a challenging task. This paper presents the results of a numerical investigation on the seismic behaviour of a representative rammed earth building located in Alentejo (South of Portugal). Numerical …
COMPORTAMENTO CICLICO DI PANNELLI SOTTILI IN ACCIAIO
2013
abstractita La memoria riporta i risultati di indagini sperimentali su pareti sottili in acciaio sottoposte ad azioni cicliche, ponendo in risalto le capacità dissipative. Le prove sono state condotte presso il laboratorio DISMAT di Canicattì (AG)su modelli in scala 1:2. I risultati evidenziano le riserve di resistenza dei pannelli in fase post critica. Results of experimental tests on Steel Plate Shear Wall (SPSW) placed in steel frames subjected to cyclic actions are presented, stressing the dissipative capacity of the system. The tests were performed at the DISMAT laboratory in Canicattì (AG) on scale specimens. The surrounding frame is made by HEA 160 beam and columns with pinned joint,…
Esposizione e vulnerabilità sismica dell'edilizia residenziale del centro storico di Caltabellotta
2020
Aiming at evaluating the seismic vulnerability of the old town of Caltabellotta, first the main characteristics of the new survey cards CARTIS for the structural typology characterization recently developed, and the bases of the macroseismic method for seismic vulnerability and fragility curve estimation, are briefly summarized. Then, the main typological and structural characteristics of the house typology in the historic centre of Caltabellotta are described, providing a synthetic estimate of the vulnerability and highlighting the probability of reaching predetermined levels of damage in relation to the intensity of the expected earthquake (fragility curves). This information, combined wi…
Variable Friction Dampers (VFD) for a modulated mitigation of the seismic response of framed structures: Characteristics and design criteria
2022
In this paper a new approach for the energy dissipation is discussed based on the use of Variable Friction Dampers (VFDs). The VFD device is borrowed from braking systems mechanical engineering, able to modulate its capability of dissipation, providing a constant pure friction force coupled with an additional (variable) damping force with the increasing of the displacement. Resorting to a previous study, the characteristics and the efficiency of the “braking” system in terms of reduction of the displacements and the restoring forces is described for SDOF systems under seismic excitations and compared with the performances achievable by classic constant friction dampers (CFDs). Then, a desig…
RC Masonry infilled frames: Experimental results and development of predictive techniques for the assessment of seismic response
2014
La presenza di tamponamenti in muratura all’interno delle maglie di strutture intelaiate induce, in presenza di azioni laterali, una sostanziale modificazione della risposta globale rispetto a quella dei telai nudi in termini di rigidezza, resistenza e capacità di spostamento. La tesi presenta i risultati di una campagna sperimentale su telai tamponati con diverse tipologie di muratura soggetti a prove di carico cicliche. Successivamente viene proposto un criterio per la modellazione semplificata del comportamento ciclico attraverso un macromodello a puntone diagonale equivalente. Una ulteriore indagine numerica è eseguita per valutare l'entità degli effetti locali dovuti all'interazione fr…
Full scale tests of the base-isolation system for an emergency hospital
2019
The paper presents the results of some full-scale tests regarding the base-isolation system of the emergency room building of the polyclinic hospital in Palermo (Italy). This building has been recently realized and its base isolation system is characterized by double friction pendulum isolators. Static lateral pushing tests were aimed at identifying fundamental mechanical properties of the whole isolation level (e.g. friction forces and stiffness) in order to verify the agreement with the design hypotheses. Further dynamic tests provided different displacements of the isolated base followed by the instantaneous release (snap-back tests), in order to verify the effectiveness, the mechanical …
Uno strumento di pianificazione per la salvaguardia degli edifici storico-monumentali. Un caso di studio: la chiesa del SS. Salvatore a Naro
2020
Il patrimonio storico, e in particolare gli edifici monumentali, sono i manufatti tra i più vulnerabili nei confronti degli eventi sismici, e spesso determinano anche gravi ripercussioni su quello che comunemente è definito ”rischio urbano”. Per la conservazione e la tutela del patrimonio culturale nei riguardi dell’azione sismica è necessario disporre di strumenti di analisi in grado di permettere la valutazione della vulnerabilità e del rischio, nonché la progettazione degli interventi di miglioramento sismico. Le Linee Guida per la valutazione e riduzione del rischio sismico del patrimonio culturale – allineamento alle nuove Norme tecniche per le costruzioni, G.U. 26.02.2011, n°47 (di se…
Influence of lateral load distribution in estimation of target displacement and capacity demand by pushover analysis
2010
Two simplified adaptive load patterns for conservative estimation of seismic demand in 2D frames by pushover analysis are presented. The influence of load pattern in assessment of target displacement and distribution of demand along the height of the structure is investigated by comparing results of non linear history analysis, and non linear static analysis for eccentric braced frames. Numerical analyses show that the proposed load patterns provide safe estimation of the seismic response more accurately than load patterns proposed by seismic code.