Papers by Marco Petrangeli
WIT transactions on engineering sciences, 1970
When using a smeared model in the nonlinear finite element analysis of concrete structure, an int... more When using a smeared model in the nonlinear finite element analysis of concrete structure, an internal length scale must be incorporated to correctly simulate the fracture mechanism in the material. This can be done with different approaches at different levels. A necessary condition for each of these approaches is to assure that a constant energy is exploited in the fracture process zone independently of the mesh size and shape (orientation). When this integral condition is not satisfied, problems of spurious mesh sensitivity will arise i.e. unobjectivity of the analysis with respect to the finite element size. The crack band approach is the most simple application of the internal scale length. At the other side, there is today the possibility of micro material modeling. In between this two extremes there are today some enhanced continuum formulations which provide an internal length scale build in the constitutive equations. The nonlocal formulation is one of these approaches where the material constitutive equations depend not only on the strain in a given point but also on the the strain field in its neighborhood. In the present paper some theoretical and numerical investigations are carried out using a new hybrid formulation of the microplane model together with the standard crack band approach as well as various nonlocal approaches recently implemented by the authors. Differences betwenn these approaches are discussed related to the problem of mesh sensitivity and size effect.
Shock and Vibration, May 20, 2022
e interaction between a pedestrian bridge for a motorway crossing and air pressure waves induced ... more e interaction between a pedestrian bridge for a motorway crossing and air pressure waves induced by the truck passage is discussed with reference to a slender footbridge in Pregnana (Italy). e experimental campaign was necessary, as very signi cant vibrations induced by truck passage were observed during the construction process before building the reinforced concrete plate on the deck. Results obtained from monitoring the air pressures and accelerations caused by the truck passage under the bridge along with truck speeds have shown a phenomenon known as a piston e ect occurring during the passage. Based on the statistical analysis of these measured values, the spatial distribution of the wave on the bridge was elaborated. Numerical analyses of the bridge without the reinforced concrete plate on the deck suggest that the piston e ect should be calculated to safely construct light bridges.
The paper presents the implementation of rebars buckling capabilities into a fibre beam element r... more The paper presents the implementation of rebars buckling capabilities into a fibre beam element recently developed by the authors and the results of numerical analyses carried out on few representative concrete structures using this new element. The fibre model used for the implementation is an equilibrium based beam element using uniaxial constitutive modelling for concrete and steel. The existing uniaxial model for the longitudinal steel fibres has been replaced with a new one with buckling capabilities based on the Menegotto-Pinto constitutive law as modified by Nuti and co-workers to account for rebar buckling in the plastic regime. The model input parameters are the steel properties, the stirrups spacing and the longitudinal rebar diameter. Four hardening rules are used to modify and shift the skeleton branch of the model at each load reversal. Calibration of the model using available test data is presented and the effect of insufficient transverse reinforcement (i.e. large stirrups spacing) on the structural response and ultimate resistance of reinforced concrete bridge piers and frames is investigated. Two case studies are also presented: the Kobe Hanshin viaduct's pier toppled during the 1995 earthquake characterised by a bending-shear driven compression failure and a large frame representative of Italian civil building designed according to prevailing anti-seismic specification of the sixties and seventies. The results of numerical analysis are discussed in order to evaluate the retrofitting strategies of these seismic sensitive structures.
Ponti & Viadotti Lʼ intervento richiede una generale risagomatura del canale navigabile ed una so... more Ponti & Viadotti Lʼ intervento richiede una generale risagomatura del canale navigabile ed una sostituzione dei ponti esistenti perché possano transitare natanti per i quali è richiesto un franco netto pari a 6,80 m sopra il pelo libero dell'acqua. La strada interessata dal nuovo ponte è classificata come extraurbana secondaria di categoria C1 con due corsie da 3,75 m più banchine laterali da 1,50 m per una larghezza complessiva di piattaforma stradale di 10,50 m. Sono previsti anche due marciapiedi di cui uno, lato Nord, di tipo ciclopedonale. Il nuovo ponte viene realizzato a fianco all'esistente che deve restare in esercizio fino al completamento e messa in funzione della nuova opera. Il progetto posto a base di gara dall'Amministrazione provinciale di Ferrara prevedeva un ponte strallato sul canale navigabile, con campata centrale da 95 m e due campate di riva da 26 m ciascuna, più due viadotti laterali d'accesso da 50 m ciascuno. In entrambi i casi erano previsti impalcati in soluzione mista acciaio-cls. L'analisi critica del progetto a base di gara ha condotto il Progettista, in fase di impostazione della soluzione costruttiva, ad una revisione sostanziale dell'opera. Pur mantenendo la scelta di tipologia strallata del ponte, si è optato per una sola struttura a tre campate, staticamente più efficace e visivamente meno impattante della precedente. Una particolare peculiarità dell'opera è costituita dalla curvatura planimetrica dell'impalcato (R = 1.000 m) richiesta da esigenze di tracciato. Questo introduce una asimmetria nella statica del sistema ed una leggera componente centripeta del tiro degli stralli.
The paper presents a numerical investigation on the behaviour of reinforced concrete bridge piers... more The paper presents a numerical investigation on the behaviour of reinforced concrete bridge piers subjected to horizontal seismic input. Scope of the investigations is to quantify the phenomenon of bending-induced axial vibrations. The results of a set of analyses conducted on single column bent systems indicate that flexural cracking produces, in fact, significant axial vibrations. Quantification of the effects related to this phenomenon can be determinant for the seismic assessment of existing bridges as well as for the design of new bridges. Likewise, performance and design forces of bearings and other anti-seismic devices can be estimated with more accuracy, based on the expected level of combined vertical and horizontal acceleration response on decks. Shear resisting mechanisms should also be sensitive to these vibrations and shear failure anticipated when a reduction in the axial contribution to the section shear capacity occurs. A tentative equation for the prediction of this...
Structural Engineering International
Abstract This paper illustrates the prosthetic reconstruction of a historic masonry viaduct in Al... more Abstract This paper illustrates the prosthetic reconstruction of a historic masonry viaduct in Algeria. Two of the viaduct arches on the left bank that collapsed because of soil instability have been replaced with a stayed girder that allows for future soil kinematics while restoring the compression in the remaining masonry arches on the right bank. The numerical simulations of the viaduct wreckage needed to assess the integrity of the standing portion and the main issues in the subsequent design and construction of this pioneering intervention are discussed.
IABSE Symposium Report, 2015
The Ferrara waterway, connecting this historic town with Comacchio on the Adriatic Sea is being u... more The Ferrara waterway, connecting this historic town with Comacchio on the Adriatic Sea is being upgraded: section widening and straightening as well as higher clearance has called for the replacement of most of the existing bridges. On the outskirt of Ostellato the conditions were appropriate for a medium span stay cable road bridge having the peculiarity of a curved girder with a plan and crest radius of 1000 metres. The structure had to be cost efficient, because it was offered as an alternative design to an awkward but smaller tender solution within the same budget. Concrete towers had to be of the inverted Y shape to resist lateral forces given by the horizontal radius, steel frames have been cast into the upper concrete section of the towers to facilitate positioning and erection of the 48 stays. The 14m wide deck sports the classical composite design with plated girders running at both sides and transverse beams at 4 metres centre; with an height of 1.5m circa for the 130 metres span, the resulting slenderness is considerable and associated with the double curvature gift the structure with elasticity and lightness.
opera di scavalco con la quale l'autostrada sovrappassa il fascio di binari del nodo di Certo... more opera di scavalco con la quale l'autostrada sovrappassa il fascio di binari del nodo di Certosa era realizzata con un viadotto a due campate con fortissima obliquità (con un angolo di incidenza pari a 29° circa) e che presentava evidenti segni di degrado (Figura 2). Nell'ambito dei lavori per la nuova linea AV, si è pertanto deciso di so-stituire tale opera con due moderni solettoni in calcestruzzo armato precompresso, uno per ogni carreggiata autostradale, di larghezza ade-guata a contenere tre corsie più banchina (18,4 m ciascuno). Dovendo realizzare una nuova struttura, Ferrovie dello Stato SpA hanno manifestato l'interesse all'eliminazione dell'appoggio intermedio, pre-sente nel vecchio manufatto sotto forma di pareti e di pilastri, e all'au-mento del franco disponibile per le linee sottostanti. La concomitanza di queste richieste ha comportato la realizzazione di una struttura con un ingombro massimo sotto la livelletta autostradale inferiore al metro su...
Bridge isolation is today very popular in the design of strategic new structures such as road-way... more Bridge isolation is today very popular in the design of strategic new structures such as road-way and railway bridges as well as in the retrofit of existing ones. With reference to the most common bridge configurations the paper try to establish some basic rules to help clients and practitioner engineers with choosing the most cost effective isolation devices based on bridge dynamics and probabilistic occurrence of seismic events. The paper specifically addresses the longitudinal seismic behaviour of continuous girders, a scheme that nowadays account for the large majority of new constructions. Their dynamic response is therefore analyzed in details comparing different configurations with and without isolation over a range of seismic intensi-ty representative of the Italian territory. The study, carried out with linear and non-linear fibre models in the time domain, provides some interesting results on the response of these struc-ture and the effect of friction on sliding bearings, ...
The paper summarises the main design and construction issues of two highly skewed post tensioned ... more The paper summarises the main design and construction issues of two highly skewed post tensioned concrete bridges built along the A4 motorway connecting Milan to Turin. The twin bridges cross over the main railway lines connecting Milan to Switzerland and to north-western Italy and France. The two structures are characterized by a very high skew (61°) and extreme slenderness. The bridges are 50m long (47m span), 20m wide each (4 lane carriageways) and 80cm thick so as to allow the required clearance for the underneath railway lines. In order to support the two slender postensioned slabs, lateral edge beams shaped in the form of crash barrier have been added on both sides. The structures are the largest and heaviest single span slabs ever built in Italy so far. The slabs were cast in situ and post-tensioned behind the abutments and subsequently push launched over the railway lines without intermediate supports so as to eliminate every possible interference with the railway operations...
Gallerie I l tracciato della nuova linea ferroviaria ad Alta Velocità (AV) Torino-Milano corre pe... more Gallerie I l tracciato della nuova linea ferroviaria ad Alta Velocità (AV) Torino-Milano corre per tutto il tratto piemontese in affiancamento sul lato Sud all'Autostrada A4. In località Pregnana Milanese, cir-ca 17 chilometri a Est del Fiume Ticino, la linea so-vrappassa l'Autostrada (unico scavalco lungo l'inte-ra tratta) spostandosi a Nord di quest'ultima (fig. 1). Una volta oltrepassata l'autostrada, la nuova ferro-via inizia l'ampia curva verso Sud-Est per entrare in Milano in affiancamento alla Linea Storica (LS). Prima di oltrepassare l'Autostrada la nuova linea AV scavalca anche la Linea Storica che in questo tratto interseca l'A4 con un sottopasso posto circa un chi-lometro prima dello scavalco della linea AV. In definitiva, per circa 4 chilometri, la nuova linea AV corre alta sul piano campagna scavalcando la Linea Storica e l'autostrada A4 con due gallerie artificiali di grandi dimensioni interamente realizzate con ele-menti in cemento ...
Facendo seguito al lavoro già pubblicato sul fascicolo di Gennaio-Febbraio di leStrade, in questa... more Facendo seguito al lavoro già pubblicato sul fascicolo di Gennaio-Febbraio di leStrade, in questa seconda parte viene indagata la vulnerabilità sismica della tipologia di viadotto stradale e ferroviario più diffusa in Italia, ovvero quello a travi poggiate con pile in cemento armato e appoggi in gomma o acciaio-teflon.
International Journal for Numerical Methods in Engineering, 1997
ABSTRACT The paper describes a procedure for the non-linear analysis of structures which are an a... more ABSTRACT The paper describes a procedure for the non-linear analysis of structures which are an assemblage of beams with material non-linearities of general type; the approach uses the equilibrium integrals and a consistent iterative formulation at the element level, within the general framework of the displacement method for the solution of the global structural problem. The application of different approaches to the non-linear beam problem is presented and discussed including the traditional stiffness and flexibility approach and some mixed formulations. The proposed equilibrium-based approach is shown to be more accurate and more robust than the traditional compatibility-based approach, on which most of the non-linear beam elements available today are based. Similar advantages are also found with respect to an approach based on the three-field mixed assumed strain method. © 1997 by John Wiley & Sons, Ltd.
Journal of Engineering …, 1999
After a few years of successful application of the fiber beam element to the analysis of reinforc... more After a few years of successful application of the fiber beam element to the analysis of reinforced concrete (RC) frames, the introduction of the mechanisms of shear deformation and strength appears to be the next necessary step toward a realistic description of the ultimate behavior of shear sensitive structures. This paper presents a new finite-beam element for modeling the shear behavior and its interaction with the axial force and the bending moment in RC beams and columns. This new element, based on the fiber section discretization, shares many features with the traditional fiber beam element to which it reduces, as a limit case, when the shear forces are negligible. The element basic concept is to model the shear mechanism at each concrete fiber of the cross sections, assuming the strain field of the section as given by the superposition of the classical plane section hypothesis for the longitudinal strain field with an assigned distribution over the cross section for the shear strain field. Transverse strains are instead determined by imposing the equilibrium between the concrete and the transverse steel reinforcement. The nonlinear solution algorithm for the element uses an innovative equilibrium-based iterative procedure. The resulting model, although computationally more demanding than the traditional fiber element, has proved to be very efficient in the analysis of shear sensitive RC structures under cyclic loads where the full 2D and 3D models are often too onerous.
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Papers by Marco Petrangeli