1,721,034 research outputs found
Interaction domains for buckling of isolated R.C. columns
No full textInteractions domains for buckling of isolated r.c. columns represent an efficient and versatile instrument for the evaluation of the resistance at ULS and allow also the optimisation of structural geometry and section reinforcement.
The paper presents the above mentioned domains for rectangular symmetrically reinforced columns and provides a detailed analysis of the load-carrying capacity for various classes of concrete and reinforcement steel. Domains have been obtained according to the model-column method, taking into account the uncertainties both in geometry and in the position of axial loads. The effects related to creep phenomena are ignored.
In order to facilitate the practical utilization, the generic domain has been approximated by a two-branch curve, parabolic and elliptic. The first-one is related to axially-dominated rupture, the second one to flexural crisis. This approximation leads to simple closed-form expressions, particularly suitable for engineering preliminary design
Rotational ductility of R.C. beams: a parametric analysis
No full textThe evaluation of plastic rotation capacity in reinforced concrete beams is essential to prevent brittle failures. In order to facilitate practical applications, the methods usually adopted in International Codes (see EC2, MC90 or DIN), provide approximate functions θpl vs (x/d)u,conv in which the following principal parameters appear: (i) ultimate concrete strength; (ii) ductility characteristics of the reinforcement steel; (iii) shear slenderness.
Indeed, more accurate formulations have highlighted, especially for slender beams, a fundamental importance of additional variables.
Hence, it is here proposed a mechanical model through the use of dimensionless expressions able to examine in a more accurate way the effects of the bending rupture for rectangular sections. The analytical approach allows to perform simple parametric analyses and evaluate the significancy of mechanical characteristics that are usually neglected in other formulations.
The following simplifications are made: (i) after the first cracking, the contribution of the concrete in the tension region is neglected; (ii) tension-stiffening effects are disregarded.
The parameters included in the model are: a) material constitutive laws; b) mechanical tensile reinforcement ratio; c) compressive-tensile reinforcement ratio; d) characteristics of the plastic part in the idealised moment-curvature relationship
Analisi fuzzy della durabilità di strutture in cemento armato soggette ad attacchi di cloruri = Fuzzy reliability analysis of reinforced concrete structures subject to pitting corrosion
No full textGaining experience in designing R.C. Structures by Strut-and-Tie model: the case of a typical bridge deck subjected to horizontal actions
No full textStrut-and-Tie Model (STM), conceived by Ritter (1899), has been developed by Mörsch. Schlaich et al.
(1987) proposed a global approach to the structural design by means of STM. Even though nowadays STM is widely
used, several difficulties can be still encountered when dealing with the choice of the model that can best fit to the actual
configuration (i.e. the ‘optimum’ model). Such problems can be even more relevant when dealing with non-standard
cases. In this paper, the case of bridge decks subjected to horizontal actions is presented. Different methods to reach
STM are shown: from FEM to Load Path Method to Bi-directional Evolutionary Structural Optimization method. The
aim is to use the examined case to evaluate the efficacy of these methods to gain experience in designing R.C. structures
with STM. Moreover, in the paper the influence on the model of the geometry of the bridge slab as well as the
distribution of longitudinal and transversal deck beams have been investigated
Gaining experience in designing r.c. structures by strut-and-tie model: the case of a typical bridge deck subjected to horizontal actions
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Rischio sismico e strategie di mitigazione nei centri storici. Il caso di Laino Castello
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Un criterio per il progetto degli isolatori antisismici per la protezione delle pile dei ponti
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