1,721,014 research outputs found
Design procedures for DCS implementation. Report to European Commission No. EVG1-CT-1999-00013 SPIDER/8.1-2/UDINE/SSO/03/VF-C, Deliverable No. 17. Research and Technological Development Project SPIDER, August 2002
No full textThis report describes a specially conceived procedure for the design of the damped cable system (DCS). The procedure is formulated according with a performance-based non-linear dynamic approach, and consists of a preliminary and a final verification phases.
The former phase is carried out by referring first to a modal transformation, and then to a single-degree-of-freedom (SDOF) dynamic idealisation of the building protected by DCS. Both schemes derive from simplified assumptions on the structural characteristics and the cable geometry, as well as on the design hypothesis of preserving a first mode-dominated seismic response also in protected conditions. The cable geometry is traced out at this stage of the analysis with the aim of approaching – within the limits imposed by the architectural constraints and the actual structural configuration – a parabolic layout, or the “constant horizontal force” one. In fact, these represent the two most performing shapes highlighted by the extensive parametric analyses carried out by Udine University team within the context of Work-Package 1, as well as in the subsequent numerical investigations developed on selected case studies [1-3].
The solving equations of motion are explicitly formulated for the non-linear dynamic SDOF problem, which can nevertheless be modelled also by commercial calculus programs including non-linear viscous dashpot elements in their basic libraries, among which the widely used SAP2000NL code.
The four-step preliminary phase is carried out by referring to the highest hazard level assumed in the performance-based approach, although additional checks can also be developed with regards to the remaining levels. The procedure is started by imposing a target reduction on the fundamental period of the unprotected structure, from which the preliminary values of cable-section area, and of first and second-branch Jarret device stiffness are determined (steps 1 and 2). The cable and device pre-loads are then evaluated by a separate criterion, where the limit top displacement of the building deemed compatible with the highest hazard level-related design objective is input (step 3). The preliminary choice of the damping coefficient of Jarret device is finally located by a parametric enquiry based on the proposed dynamic SDOF model (step 4)
Analisi delle caratteristiche di dissimmetria di segnali sismici generati mediante procedimenti di calcolo. Atti dell’Istituto di Energetica, Sez. Strutture, Facoltà di Ingegneria, Università di Perugia, Pubbl. N. 1/1992
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Semiosis in cognitive systems: a neural approach to the problem of meaning
No full textThis paper deals with the problem of understanding semiosis and meaning in cognitive systems. To this aim we argue for a unified two-factor account according to which both external and internal information are non-independent aspects of meaning, thus contributing as a whole in determining its nature. To overcome the difficulties stemming from this approach we put forward a theoretical scheme based on the definition of a suitable representation space endowed with a set of transformations, and we show how it can be implemented, in the case of a single agent, by a neural network architecture. Numerical experiments conducted on different instances of the latter show that similar representations are developed as a consequence of the fact that these instances are facing a similar semantic task. This allows to model social and environmental influences through a system of interacting agents, each described by a specific implementation of this model architecture
A neural solution to symbol grounding problem
No full textThis contribution introduces a neural architecture, based on interconnected artificial neural networks, able to solve the grounding problem. Some extended simulations show the ability of this architecture in building a connection between symbols and meanings by starting from the presentation of example
Active Confinement of Structural Members for Seismic Strengthening of R/C Frame Buildings
No full textActive confinement (AC) of structural members is gaining growing attention in the academic and professional
communities as advanced seismic retrofit strategy of buildings. The study presented here is focused on the application of a highly
performing AC technology, so named CAM (Active Confinement of Masonry), conceived over than twenty years ago in Italy for
masonry structures, and subsequently adapted with effective results to reinforced concrete ones (named, for extension, CAM-R/C).
A representative case study is particularly examined, i.e. a school built in the early 1960 in Friuli Venezia Giulia region, Italy. A
seismic assessment analysis of the building is carried out in its current conditions, also supported by preliminary diagnostic
investigations, which highlights several seismic deficiencies, especially in terms of shear response of columns and beams.
Thus, a retrofit intervention based on the application of the CAM-R/C system is designed, which allows attaining a substantial
improvement of the structural performance.
A detailed description of the case study characteristics, the design criteria adopted for the considered seismic strengthening strategy,
drawings of the interventions, and a synthesis of the seismic analyses developed in original and retrofitted configurations are offered
in the pape
Calibrazione delle caratteristiche elastico-dissipative di dispositivi siliconici per l’isolamento di edifici soggetti a vento
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