1,249 research outputs found
Correction to: A probabilistic investigation on the dynamic behaviour of pile foundations in homogeneous soils
No full textDue to proofing error, author surnames were reversed and should correctly read as: Lucia Minnucci, Michele Morici, Sandro Carbonari, Francesca Dezi, Fabrizio Gara, Graziano Leoni Original article has been updated
Closure to "Effective slab width in prestressed twin-girder composite decks" by Luigino Dezi, Fabrizio Gara, and Graziano Leoni
No full textClosure of authors to a discussion by Marián Rovňák, Antónia Ďuricová and Ĺudmila Rovňáková to "Effective Slab Width in
Prestressed Twin-Girder Composite Decks
Creep and shear-lag coupling in steel-concrete composite beams
No full textUnder the assumption of linear viscoelastic behaviour for the concrete slab and linear elastic behaviour for the steel beam, a model for analysing the shear-lag effect in steel-concrete composite beams, is proposed. By supposing that the slab loss of planarity is described by a fixed warping function, the vertical and longitudinal displacements of the generic cross section and the intensity of the warping (shear-lag function) are assumed as unknowns of the problem. Integrating by parts the global balance condition obtained by the virtual work principle, three linear integral differential equations (expressing local equilibrium) with the relevant boundary conditions are obtained. Such a system is numerically solved by a step-by-step procedure combined with the finite differences method. Some applications on beams subjected to static actions show the practical uncoupling between creep and shear-lag
Displacement-based formulations for composite beams with longitudinal slip and vertical uplift
No full textThis paper describes three novel displacement-based formulations for the analysis of composite beams with a flexible connection which is capable of deforming along the longitudinal axis of the member as well as vertically, i.e. transverse to the interface connection. For completeness, the analytical model which forms the basis of the proposed modelling technique is presented in both its weak and strong forms. The three novel finite element formulations are derived and tested using different structural systems; their nodal freedoms include the vertical and axial displacements as well as the rotations at each element end of both layers. Curvature locking problems are observed to occur for one of these elements and the origin of this behaviour is demonstrated analytically. Two applications are then proposed adopting a bi-linear constitutive relationship for the vertical interface connection to, reflect the more realistic case in which, already in the linear-elastic range of the materials forming the cross-section and of the longitudinal interface connection, two vertical connection stiffnesses are required, i.e. one to model the event of separation between the layers and one when one bears against the other one. Copyright (c) 2005 John Wiley & Sons, Ltd
Modelling Strategies for the Updating of Infilled RC Building FEMs Considering the Construction Phases
No full textThis paper deals with modelling strategies for the updating of Finite Element Models (FEMs) of infilled Reinforced Concrete (RC) frame buildings. As is known, this building typology is the most adopted worldwide for residential houses and strategic buildings, such as hospitals, schools, police stations, etc. The importance of achieving trustworthy numerical models for these kinds of structures, especially the latter ones, is clear. The updating procedure mainly consists in changing the geometrical and mechanical material properties of models until pre-determined convergence criteria are verified, the latter based on the comparison between numerical and experimental outcomes. In this work, the modelling strategies that can be adopted to refine FEMs of infilled RC buildings are treated in-depth, starting from the simple model usually developed for design purposes. Modelling techniques relevant to the geometry, the mechanical properties, the mass, and the restraint conditions of the model are discussed. Moreover, the approaches that can be adopted to calibrate numerical models during the construction process are addressed as well. Then, an application of the proposed strategies is provided with reference to a real building that was investigated during its construction. The proposed modelling strategies proved to be effective in the model updating of the considered building and provide useful support for the calibration of FEMs of this building typology in general
Partial Interaction Analysis With Shear-lag Effects of Composite Bridges: A Finite Element Implementation For Design Applications
No full textThis paper presents a numerical model for the analysis of composite steel-concrete beams with partial interaction to account for the deformability of the shear connection. The proposed approach is capable of capturing the structural response produced by shear-lag effects and by the time-dependent behaviour of the concrete. The versatility of the FE formulation is demonstrated for a wide range of realistic bridge arrangements, e.g. from twin-deck girders to cable-stayed bridges. The accuracy of the approach is validated against the results obtained from more refined models generated with shell elements using commercial finite element software. For each bridge typology considered, both deformations and stresses are calculated to provide greater insight into the structural performance. Particular attention is placed on the determination of the effective width to be used for design purposes and on the stress distribution induced in the concrete component, together with their variation with time due to creep and shrinkage
La larghezza efficace della soletta nei ponti con impalcato composto acciaio-calcestruzzo
No full textA study on the slab effective width of steel-concrete composite decks is presented. By using an analytical beam-model presented by the authors, the shear-lag effect is investigated on continuous twin-girder composite decks under static, geometrical and thermal actions and when internal and external prestressing techniques are adopted. Separately for each action, the elastic and the long-term stress distributions on the slab are reported. The dependence of the slab effective width on the type of the action is put in evidence. A parametric analysis shows that the slab effective width is weakly dependent on time, shear connection stiffness and steel beam inertia while it is strongly influenced by the span length and by the beam spacing. Finally, some correlation formulas between the slab effective width and the span length and between the slab effective width and the steel beam spacing are proposed
Finite element formulation for the analysis of composite bridges with complex static schemes
No full textThis paper presents the derivation of a finite element formulation for the analysis of composite decks accounting for partial interaction theory and shear-lag effects. The particularity of the proposed element, referred to as the deck finite element, relies on its ability to capture the structural response of complex static schemes, such as those specified for arch, bow-string and cable stayed bridges, while preserving the ease of use of a typical line element. For these particular bridge solutions, stress concentrations may be induced in the slab by the application of concentrated forces, i.e. due to the anchorage of prestressing cables or stays, or due to the presence of web members in arch bridges. The ease of use of the proposed deck finite element is outlined considering two case studies for which the calculated results have been compared against those obtained using a more refined model implemented using shell elements in a commercial finite element software
Analysis of the Shear Lag Effect in Composite Bridges with Complex Static Schemes by means of a Deck Finite Element
No full textThis paper presents the derivation of a finite element formulation for the analysis of composite decks accounting for partial interaction theory and shear-lag effects. The particularity of the proposed element, referred to as the deck finite element, relies on its ability to capture the structural response of complex static schemes, such as those specified for arch, bow-string and cable stayed bridges, while preserving the ease of use of a typical line element. For these particular bridge Solutions, stress concentrations may be induced in the slab by the application of concentrated forces, i.e. due to the anchorage of prestressing cables or stays, or due to the presence of web members in arch bridges. The ease Of use of the proposed deck finite element is Outlined considering two case Studies for which the calculated results have been compared against those obtained using a more refined model implemented using shell elements in a commercial finite element software
Time analysis of composite beams with partial interaction using available modelling techniques: A comparative study
No full textThis paper presents a comparison of available numerical structural formulations for the short- and long-term analysis of composite beams with partial shear interaction. The finite difference method, the finite element method, the direct stiffness method and the exact analytical model have been considered, and both the instantaneous analysis and the time analysis based on the age-adjusted effective modulus method (AEMM) have been carried out. For modelling based on the first two of these formulations, a spatial discretisation and a discretisation in the time domain are required, while only the time discretisation needs to be specified for the direct stiffness method. The results obtained using these formulations are compared qualitatively and their accuracy is estimated, adopting the exact analytical model as a benchmark reference with the objective of establishing the minimum spatial discretisations required to keep the error within an acceptable tolerance. These comparisons are carried out for simply supported beams, propped cantilevers and fixed ended beams, from which the qualitative behaviour of these formulations in the modelling of continuous beams can also be deduced. (c) 2005 Elsevier Ltd. All rights reserved
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