217 pubblicazioni classificate nel seguente modo:

Il controllo della fessurazione negli impalcati continui a sezionecomposta
Atti del XIX Congresso CTA
Autore/i: Dezi, Luigino; Gara, Fabrizio; Leoni, G.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/74230

Shear-lag effect in twin-girder composite decks
STEEL AND COMPOSITE STRUCTURES
Autore/i: Dezi, Luigino; Gara, Fabrizio; G., Leoni
Classificazione: 1 Contributo su Rivista
Abstract: The paper presents a model for analysing the shear-lag effect on the slab of twin-girder composite decks subjected to static actions, support settlements and concrete shrinkage, which are the main actions of interest in composite bridge design. The proposed model includes concrete creep behaviour and shear connection flexibility. The shear-lag in the slab is accounted for by means of a new warping function. The considered actions are then applied to a realistic bridge deck and their effects are discussed. The proposed method is utilised to determine the slab effective widths for three different width-length ratios of the deck. Finally, a comparison between the results obtained with the Eurocode EC4-2 and those obtained with the proposed model is performed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/75139

Slab cracking control in composite decks by means of fractionated castings
Int. Conf. on Advances in Structures – Steel, Concrete, Composite and Aluminum, ASSCCA’03
Autore/i: Dezi, Luigino; Gara, Fabrizio; G., Leoni; A., Vitali
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: ABSTRACT: This paper presents a study on the control of the slab cracking tendency in steel-concrete decks, achieved by optimising the slab casting. After a brief description of the numerical model proposed by the authors, the results of calculations performed with reference to different sample decks are presented by showing the stress distribution obtained by continuous and sequential castings. The effects of the early age shrinkage due to cooling of the concrete are reported and the effects of tensile creep behaviour of the concrete are examined. Finally, the effectiveness of sequential casting in controlling cracking both at early age and in the long term is shown.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/52516

La larghezza efficace della soletta nei ponti con impalcato composto acciaio-calcestruzzo
Atti del V Workshop Italiano sulle Strutture Composte
Autore/i: Gara, Fabrizio; G., Leoni
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: ABSTRACT A 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.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/74881

Shear-Lag effect in prestressed composite twin-girder decks
Proceedings of the 3rd European Conference on Steel Structures, Eurosteel
Autore/i: Dezi, Luigino; Gara, Fabrizio; Leoni, G.
Editore: cmm – associação Portuguesa de Construção Metálica e Mista, Guimarães, Portugal
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: ABSTRACT The shear lag effect in composite twin-girder decks is analysed by considering the main prestressing techniques, namely support settlements, cables inside the concrete slab and external slipping cables. The theoretical model, which includes concrete creep behaviour and the shear connection flexibility, describes the non-uniform stress distribution on the slab by means a warping function taking into account the real position of the two beams. Numerical applications are carried out on a realistic bridge deck by separately considering the prestressing systems listed above. The effective slab width describing the shear-lag effect on the cross section and its evolution in time are evaluated for each kind of prestressing and compared with those given by the method suggested by the European Code ENV1994-2.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/63572

Mutual effects between creep, connection deformability and shear-lag in steel-concrete composite bridges
6th Int. Conf. on Creep, Shrinkage and Durability Mechanics of concrete and other quasi-brittle Mate
Autore/i: Gara, Fabrizio; G., Leoni; A. M., Tarantino
Editore: Elsevier B.V., Amsterdam, The Netherlands
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Based on a theoretical model, recently proposed by the authors for the viscoelastic analysis of composite steel-concrete beams, a further analysis is developed to investigate numerically the mutual influence between concrete creep, connection deformability and shear-lag effect.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/47520

Effective slab width in twin-girder composite decks
Proceedongs of the 1st Int. Conf. on Steel and Concrete Structures, ICSCS’01
Autore/i: Dezi, Luigino; Gara, Fabrizio; Leoni, G.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: ABSTRACT A theoretical model recently proposed by the authors for the visco-elastic analysis of steel-concrete composite beams with flexible shear connection is generalised in order to investigate the shear-lag effect in twin-girder composite decks under static, geometrical, and thermal actions. A suitable warping function is derived to catch the effect of the real beam position. Some applications are carried out on a realistic bridge deck and comparisons between results provided by the proposed model and those given by the EC4-2 method are performed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/63571

Time-dependent analysis of shear-lag effect in composite beams
JOURNAL OF ENGINEERING MECHANICS
Autore/i: Dezi, Luigino; Gara, Fabrizio; G., Leoni; A. M., Tarantino
Classificazione: 1 Contributo su Rivista
Abstract: Taking into account the long-term behavior of the concrete, a model for analyzing the shear-lag effect in composite beams with flexible shear connection is proposed. By assuming the slab loss of planarity described by a fixed warping function, the linear kinematics of the composite beam is expressed by means of four unknown functions: the vertical displacement of the whole cross section; the axial displacements of the concrete slab and of the steel beam; and the intensity of the warping (shear-lag function). A variational balance condition is imposed by the virtual work theorem for three-dimensional bodies, from which the local formulation of the problem, which involves four equilibrium equations with the relevant boundary conditions, is achieved. The assumptions of linear elastic behavior for the steel beam and the shear connection and of linear viscoelastic behavior for the concrete slab lead to an integral-differential type system, which is numerically integrated. The numerical procedure, based on the step-by-step general method and the finite-difference method, is illustrated and applied to an example of practical interest.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/75140

Shear-lag effect in prestressed twin-girder composite decks
Atti del "IV Workshop Italiano sulle Strutture Composte"
Autore/i: Dezi, Luigino; Gara, Fabrizio; Leoni, G.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/74197

Shear-lag, connection deformability and creep effects in steel-concrete composite beams
Autore/i: Gara, Fabrizio
Classificazione: 3 Libro
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/74952

Long term behaviour of composite continuous two-beam decks with HPC slab
Atti del XVII Congresso CTA
Autore/i: Dezi, Luigino; Gara, Fabrizio; Leoni, G.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/74187

Analisi comparativa di nuovi modelli di viscosità e ritiro negli HPC
Atti delle Giornate di Studio su “La sicurezza delle strutture in calcestruzzo ad alte prestazioni”
Autore/i: Dezi, Luigino; Gara, Fabrizio; Leoni, G.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/74180

Effetti della viscosità nelle travi composte con solette in calcestruzzo ad alte prestazioni
Atti delle Giornate di Studio su “La sicurezza delle strutture in calcestruzzo ad alte prestazioni”
Autore/i: Dezi, Luigino; Gara, Fabrizio; Leoni, G.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/74183

Creep and shear-lag coupling in steel-concrete composite beams
Atti del III Workshop Italiano sulle Strutture Composte
Autore/i: Gara, Fabrizio; G., Leoni
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: ABSTRACT Under 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.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/74902

Recenti modelli di viscosità per l’analisi di strutture in calcestruzzo
Atti del 12° Congresso C.T.E
Autore/i: M. A., Chiorino; Dezi, Luigino; Gara, Fabrizio; G., Lacidogna
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: SUMMARY In this paper the recent creep models for creep prediction analysis proposed by Bazant (B3 model) and Gardner (GZ model) are analyzed and compared with the CEB 90 model. The comparison among the three models is performed by considering the most important functions for time-dependent structural analysis, namely creep function J(t, t0), relaxation function R(t, t0), redistribution function csi(t, t0, t1) and aging coefficient chi(t, t0) of the AAEM method.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/74907

Accoppiamento tra viscosità e shear-lag nelle travi composte acciaio-calcestruzzo
Atti del 12° Congresso C.T.E.
Autore/i: Dezi, Luigino; Gara, Fabrizio; Leoni, G.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/74176

Effetto shear-lag nelle travi composte con connessione flessibile
Atti XVI Congresso C.T.A.
Autore/i: Dezi, Luigino; Gara, Fabrizio; Leoni, G.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/74169