305,307 research outputs found
Indirizzi per le linee guida per la ricostruzione a scala urbana
No full textIl volume contiene i primi risultati di uno studio interdisciplinare sul Comune di Poggio Picenze (AQ), condotto da docenti delle Università di Chieti-Pescara nell'ambito del Protocollo d'Intesa Interlab stipulato con la Regione Abruzzo e sei Comuni del cratere all'indomani del sisma del 6 aprile 2009. L'attività di studio, coordinata fin qui dal Prof. Enrico Spacone dell'Università "G. D'Annunzio" di Chieti-Pescara, ha comportato nei primi mesi successivi al sisma una immediata ricognizione dei luoghi da diversi punti di vista (strutturale, urbanistico, storico, architettonico) poi confluita in una più meditata analisi interdisciplinare ancora in corso volta a prefigurare possibili scenari di ricostruzione e sviluppo sostenibile per il Comune di Poggio Picenze e per l'intero sistema territoriale. La stesura del testo riflette la natura in fieri dello studio e vuole costituire una prima testimonianza del lavoro svolto e delle attività in corso, nella consapevolezza che condividere quanto fin qui acquisito sia indispensabile per ottimizzare l'efficacia delle attività future previste dal Protocollo d'Intesa Inter-Lab
Analysis of Reinforced Concrete Elements Including Shear Effects
Get PDFThis paper deals with the analysis of reinforced concrete (RC)plane frames under monotonic and cyclic loading, including axial,bending, and shear effects. A force-based two-dimensional (2D)element based on the Timoshenko beam theory is introduced. Theelement formulation is general and yields the exact solution withinthe Timoshenko beam theory. A simple, nonlinear, shear force-shear deformation law is used at the section level, together with aclassical fiber section for the axial and bending effects. Sheardeformations are thus uncoupled from axial and bending effects inthe section stiffness, but shear and bending forces become coupledat the element level because equilibrium is enforced along thebeam element. The element is validated through comparisons withexperimental data on the shear performance of bridge columns.The seismic analysis of a viaduct that collapsed during the 1995 Kobe earthquake is presented
Reinforced concrete fiber beam element with bond slip
No full textThis paper presents a new reinforced concrete beam finite element that explicitly accounts for the slip between the reinforcing bars and the surrounding concrete. The element formulation combines the fiber-section model with the finite-element model of a reinforcing bar with continuous slip. The section model retains the plane-section assumption, but the steel fiber strains are computed as the sum of two contributions, the rebar deformation and the anchorage slip. The model applies to any cross-sectional shape under biaxial bending and both monotonic and cyclic loads. The model theoretical framework is presented first. A sensitivity study on the monotonic and cyclic response of a reinforcing bar shows how the model traces the bar's reduced initial stiffness, bond degradation, and anchorage loss for insufficient anchorage length. Finally, comparison with an experimental test on a circular column shows that the prediction with the new model is in good agreement with the test, whereas the original fiber model with perfect bond overestimates the hysteretic energy dissipated during the loading cycles
Role of Bond in RC Beams Strengthened with Steel and FRP Plates
No full textThis paper discusses the problem of predicting the stiffness, the loading capacity and the failure modes of RC members strengthened in bending with bonded steel or C-FRP plates. A definitely week critical issue of this strengthening technique is that when the plate debonds, e failure that follows if the plate detachment occurs: in this case, the loading capacity suddenly drops and the failure mode is typically brittle. Due to both the concrete cracking diffusion and the yielding of the steel rebars, a significant amplification of the bond stresses takes place at the beam-plate interface. then Delamination occurs when the bond strength is locally reached. In order to properly describe and realistically predict the behavior of the strengthened beams, a displacement-based fiber beam element is used. Bond slip between the beam and the plate is included by assuming separate displacement fields in the beam and in the strengthening plate. The proposed model is used to confirm and explain distinct failure modes observed in experimental investigations
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