enzo siviero - ordem dos engenheiros · 2020. 4. 8. · enzo siviero ecampus university rector...

Enzo SivieroeCampus University Rector – Novedrate Italy

Riccardo Morandi’s Bridge

in Genova from Tragedy to a

New Reinassance

PONTE SAN MICHELE DI PADERNO D'ADDA 1889

Capolavoro riconosciuto come uno dei simboli di archeologia industriale del Paese.

Nel 2017 è stato candidato per essere inserito nella lista UNESCO dei patrimoni

dell'umanità.

FORTH BRIDGE – SCOZIA 1890

Considerato una meraviglia dell'era industriale, è dichiarato parte del

patrimonio UNESCO nel giugno 2015

FORTH BRIDGE

VIADOTTO DI GARABIT – EIFFEL- FRANCIA 1884

PONTE DOM LUIS I – EIFFEL- PORTOGALLO 1886

RICCARDO MORANDI

Studi e proposte per il ponte di

Messina, 1971/89

…il ponte di Morandi non incorre

nelle ambiguità teoriche simmelliane

tra il senso del dividere e il senso

dell’unire: esso, semplicemente,

scavalca, oltrepassa, lanciandosi da

una sponda all’altra; a grandi balzi o

a piccoli; o addirittura galleggiando

sull’acqua.

Dell’ambiente, assume tutto cio’ che

lo spazio circostante trasmette

all’attento e selettivo ascolto del

progettista, capace di concentrare

nella sua scelta formale, sostenuta

dallo strumento del calcolo e dagli

stimoli oggettivi della funzione, le

qualità peculiari del genius loci.

(M.Manieri Elia)

RICCARDO MORANDI – PONTE SULLO STORMS RIVER (1953)

Studio dello stato di

sollecitazione nella fase

precedente la chiusura

dell’arco

RICCARDO MORANDI – PASSERELLA A LUCCA (1953-54)

Studio del comportamento statico dei semiarchi

RICCARDO MORANDI – PASSERELLA A LUCCA (1953-54)

RICCARDO MORANDI – VIADOTTO SULLA FIUMARELLA,

CATANZARO (1962)

RICCARDO MORANDI – PONTE A MARACAIBO (1957-62)

RICCARDO MORANDI – VIADOTTO SUL POLCEVERA (1962-67)

RICCARDO MORANDI – PONTE SUL WADI EL KUF CIRENAICA (1965/71)

Questo ponte, che scavalca una profonda

incisione dell’altopiano Cirenaico e che fa parte

della grande strada che percorre, lungo il

Mediterraneo, tutta la Libia, è fra le piu’ grandi

opere in calcestruzzo eseguite fino a ora,

soprattutto per la sua luce. Quando fu eseguito

riusltava l’unica opera dell’uomo in un panorama

senza fine, bellissimo, fatto di rocce colorate e

profondamente incise… (R.M.)

RICCARDO MORANDI – PONTE SUL WADI EL KUF CIRENAICA (1965/71)

RICCARDO MORANDI - Ponte Alberto Pumarejo (Barranquilla, Colombia) 1970-1974

RICCARDO MORANDI -Viadotto Carpineto, Raccordo autostradale 5-Basilicata 1977

RICCARDO MORANDI

VIADOTTO SUL POLCEVERA (1962-67)

RICCARDO MORANDI – VIADOTTO SUL POLCEVERA (1962-67)

VIADOTTO SUL POLCEVERA

_______

Mario De Miranda

RICCARDO MORANDI – VIADOTTO SUL POLCEVERA

14 AGOSTO 2018 – IL CROLLO

TWO HYPOTHESES OF THE MORANDI’S BRIDGE COLLAPSE

The failure of deck and/or struts

3D and FE model of the bridge

Models developed and processed by ICARO PROGETTI, Michele Fabio Granata, PhD. Cooperated by: Eng. G. Longo, Eng. R. Nocifora, Arch. B. Fontana

The hypothesis is corroborated by the fact that the central deck area is deprived of prestressing and the effect of axial stress due to the horizontal component of the stay is considerably reduced.

Furthermore, the negative moments due to the loads on the deck increase.In the original project the ordinary reinforcement bars of concrete box were very limited and the box presented a

high fragility with no ductility. A reduction of stay axial stress induces a settlement of the deck end and the negative bending moment increases significantly

First hypothesis: the deck cracks at the centre between struts and the collapse begins from the deck box


Stays are still in place, stresses increase into struts and side spans collapse


Struts collapse, stays pull the deck ends, cracking and collapsing. The deck goes down


The collapse is quasi-symmetric but the last stay loaded pulls the tower, increasing the tension in the pylon leg, until the total collapse

The hypothesis is corroborated by the fact that the end sections of the struts are overstressed and

represent a weak point of Morandi scheme. In this case the sudden lack of struts immediately

compromises deck and stays, as suggested by the FE model

Second hypothesis: the strut cracks and the collapse begins from below


Struts collapse immediately, stays are still in place, stresses increase into the deck and side spans collapse

The deck collapse going down and taking the stays at their stress limit; stays crack and collapse


The collapse is quasi-symmetric but the last stay loaded pulls the tower, increasing the tension in the pylon leg, until the total collapse


From the evaluation of the state of the pre-collapse bridge, if we consider the sudden breaking of the strut below the

deck on one side we immediately notice that this also involves the shearing of the twin strut on the other side. It

follows that the break can be considered almost symmetrical in this case and that the elements to go into crisis

immediately afterwards are the deck (due to the strong increase of moment due to the lack of intermediate support in

the span) and the struts; stays are compromised only in a second moment (for the increased tension).

It is not possible to establish “a priori” which of the two elements goes into crisis first (if the deck or struts), since the

effect is immediate in both, but it is evident the sudden increase of tensile stresses at the edges of the deck, which

suggest a fragile break in the span and only as a consequence of the deformation of the deck, the postponement of

the stays and their compromise.

In this case the stays are very weak at anchorages. It would therefore derive that the bridge collapses "kneeling" with

a sudden rupture of the deck and with a closure of the same “as a book" that also involves the tearing of the stays. On

the other hand, it is not immediately understandable what happens to the tower, since it does not seem that it is

clearly compromised, not showing stress states incompatible with the section. Of course, in the case of a stay break

before the deck instead the pile would be immediately compromised. Therefore its collapse cannot be presumed a

priori, also due to the independence of the struts and deck from the tower, in fact the last one carries only the stays

and generally suffers due to an imbalance between the stay axial stress or a twist.

Deck and struts are the weak elements of the bridge, not stays!!


LE PROPOSTE

_______

Il recupero della parte crollata

Alessandro STOCCO

Enzo SIVIERO

www.studioip.it/ [email protected]

UNA PROPOSTA PER IL VELOCE RIPRISTINO

DEL COLLEGAMENTO SUL POLCEVERAOttobre, 01 2018


LE PROPOSTE

_______

Totale demolizione e ricostruzione

Ricciardello Costruzioni


LE PROPOSTE

_______


Renzo Piano


LE PROPOSTE

_______


Cimolai


LE PROPOSTE

_______

In affiancamento


SOLUZIONE SCELTA

_______


Renzo Piano

UN CASO EMBLEMATICO

PONTE DI DESENZANO

Ponte di Desenzano

progettato dall'ing. Luigi Negrelli partire dal 1850

Ponte di Desenzano

Dopo il bombardamento del 1943

Il viadotto di Desenzano oggi

[email protected]

Thanks for the attention

enzo siviero - ordem dos engenheiros · 2020. 4. 8. · enzo siviero ecampus university rector...

Documents