0000000000596843
AUTHOR
Piercarlo Margiotta
Concrete arch bridges erected by suspended cantilever method vs cable–stayed bridges
Concrete arch bridges built by lattice cantilevers
In this paper a study about concrete arch bridges built by lattice cantilevers is presented. Lattice cantilevers are partial structures composed of deck, arch, piers and provisional steel diagonals, organized as reticular cantilever girders, in order to build arch bridges without the use of centrings, supports or temporary towers. Characteristics of this construction methodology with its variants are explained together with their implications in the erection sequence. Partial elastic scheme method is implemented in order to find initial forces of temporary cables and a forward analysis is carried out to follow the actual sequence of construction, by extending a procedure already applied to …
I PONTI AD ARCO IN CALCESTRUZZO SOSTENUTI DA CAVI NELLE FASI DI COSTRUZIONE ED ESERCIZIO
Il controllo delle deformazioni differite nel tempo attraverso la precompressione bilanciata nei ponti a piastra
L’INFLUENZA DEI FENOMENI LENTI NELLA COSTRUZIONE E NELL’ESERCIZIO DEI PONTI IN C.A.P.PARTE II: PONTI A SCHEMA VARIATO
Partial Elastic Scheme Method in Cantilever Construction of Concrete Arch Bridges
AbstractIn this paper, a study about stay stressing procedures of concrete arch bridges built by cantilevering with temporary stays is presented. Particularly, the partial elastic scheme method is proposed to find the initial cable forces, and a forward procedure is implemented to follow the actual sequence of construction by extending a procedure already applied to concrete cable–stayed bridges. The theoretical treatment is followed by a numerical application on a case study of a concrete arch bridge, and a comparison between initial cable forces found by the partial elastic scheme method and classical backward analysis is presented here. Results show the effectiveness of the proposed proc…
LA SEQUENZA DI TESATURA NELLA COSTRUZIONE DEI PONTI STRALLATI CON IMPALCATO MISTO ACCIAIO-CALCESTRUZZO
Struttura e fondazioni del ponte di Calatrava a Venezia
IL METODO DEGLI SCHEMI ELASTICI PARZIALI NELLA COSTRUZIONE A SBALZO DEI PONTI AD ARCO
In questo lavoro viene presentato uno studio sulle sequenze di tesatura degli stralli nei ponti ad arco costruiti per sbalzi successivi con l’ausilio di tiranti provvisori. In particolare viene presentato il metodo degli schemi elastici parziali, proposto per la determinazione degli sforzi iniziali nei cavi. Tale metodologia è stata dapprima applicata sui ponti strallati e viene estesa in questo studio al caso dei ponti ad arco costruiti per sbalzi successivi. La trattazione teorica è seguita da un’applicazione numerica su un caso studio di un ponte ad arco in calcestruzzo.
L'influenza dei fenomeni lenti nella costruzione e nell'esercizio dei ponnti in c,aa.p. - Parte I: Basi teoriche
TIME-DEPENDENT EFFECTS IN SEGMENTAL BRIDGES: PREDICTIVE MODELS AND ANALYSIS VIA SIMPLIFIED METHODS
Hamiltonian structural analysis of curved beams with or without generalized two-parameter foundation
The solution of curved Timoshenko beams with or without generalized two-parameter elastic foundation is presented. Beam can be subjected to any kind of loads and imposed external actions, distributed or concentrated along the beam. It can have external and internal restraints and any kind of internal kinematical or mechanical discontinuity. Moreover, the beam may have any spatial curved geometry, by dividing the entire structure into segments of constant curvature and constant elastic properties, each segment resting or not on elastic foundation. The foundation has six parameters like a generalized Winkler soil with the addition of other two parameters involving the link between settlements…
A parametric study of curved incrementally launched bridges
Abstract The structural behaviour of incrementally launched bridges in the construction stages depends on different parameters involving deck, nose, supports and guide devices, because static schemes vary continuously with the advance of the deck above the piers. For this reason temporary stresses in the deck, during launching, are rather different from those occurring in service life. Horizontally curved launched bridges also present the effects of torsion induced by geometric curvature. A parametric study is presented in order to analyse the influence of design parameters on the construction of these bridges. Analyses were carried out by extending to curved beams a procedure based on the …
Footbridge2008. Passerelle pedonali.
Construction stages of cable-stayed bridges with composite deck
A cable-stayed bridge is built by following a construction sequence of different subsequent stages that imply changes of the geometric configuration, restraints and consequently stress and strain patterns. A study is presented about stay stressing sequences in cable-stayed bridges with composite deck for the case of construction made by the cantilever method. Initial cable forces are found through partial elastic schemes of construction stages. Different stay stressing procedures are implemented and a comparison between them is proposed in order to evaluate the differences in terms of deformed shape and internal force distribution of the deck and the pylon. Results can be useful to give pra…
LA VISCOSITÀ NEI PONTI A CONCI IN C.A.P. NORMATIVE E METODOLOGIE DI ANALISI A CONFRONTO
Ponti ad arco a spinta eliminata tramite l'impiego di passerelle a banda tesa
Simplified Procedure for Evaluating the Effects of Creep and Shrinkage on Prestressed Concrete Girder Bridges and the Application of European and North American Prediction Models
The effects of time-dependent phenomena on concrete prestressed girder bridges are investigated. The study concerns the case of bridges built directly in their final configuration and that of bridges built by a sequence of stages in which geometry, restraints, and loads vary until the final configuration is achieved. An analytical approach based on the principles of aging linear viscoelasticity and the age-adjusted effective modulus method is followed. The paper has two aims: the first is to provide an efficient and simplified tool for the evaluation of the structural response in the early stages of design; the second is to compare the results of the analyses on actual cases of bridges when…