Ponte Morandi | |
---|---|
Coordinates | 44°25′33″N08°53′20″E / 44.42583°N 8.88889°E |
Carried | Four lanes of roadway |
Crossed | |
Locale | Genoa, Liguria, Italy |
Official name | Viadotto Polcevera |
Characteristics | |
Design | Cable-stayed bridge |
Total length | 1,182 metres (3,878 ft) |
Height | Piers 90.5 metres (297 ft), Road Deck 45 metres (148 ft) |
Longest span | 210 metres (690 ft) |
Clearance above | 40 metres (130 ft) |
History | |
Designer | Riccardo Morandi |
Construction start | 1963 |
Construction end | 1967 |
Opened | 4 September 1967 |
Collapsed | 14 August 2018 |
Destroyed | 28 June 2019 |
Location | |
Ponte Morandi (English: Morandi Bridge), officially Viadotto Polcevera (English: Polcevera Viaduct), [1] was a road viaduct in Genoa, Liguria, Italy, constructed between 1963 and 1967 along the A10 motorway over the Polcevera River, from which it derived its official name. It connected Genoa's Sampierdarena and Cornigliano districts across the Polcevera Valley. The bridge was widely called "Ponte Morandi" after its structural designer, engineer Riccardo Morandi. [2]
On 14 August 2018, a 210-metre (690 ft) section of the viaduct collapsed during a rainstorm, killing forty-three people. The collapse led to a year-long state of emergency in the Liguria region, extensive analysis of the structural failure, [3] and widely varying assignment of responsibility.
The remains of the original bridge were demolished in June 2019. The replacement bridge, the Genoa-Saint George Bridge was inaugurated a year later. [4]
Ponte Morandi was designed by civil engineer Riccardo Morandi, from whom its unofficial name was derived. It was a cable-stayed bridge characterised by a prestressed concrete structure for the piers, pylons and deck, [5] very few stays, as few as two per span, and a hybrid system for the stays constructed from steel cables with prestressed concrete shells poured on. [6] [7] The concrete was prestressed only to 10 MPa (1,500 psi),[ citation needed ] making it susceptible to cracks, water intrusion, and corrosion of the internal steel. [8] [9] [10] The bridge was similar to Morandi's earlier 1957 design for the General Rafael Urdaneta Bridge in Venezuela [11] except for the stays, which on the Venezuelan bridge are not covered with prestressed concrete.
The viaduct was built between 1963 and 1967 by the Società Italiana per Condotte d'Acqua, costing 3.8 billion Italian lire and opened on 4 September 1967. It had a length of 1,182 metres (3,878 ft), a height above the valley of 45 metres (148 ft) at road level, and three reinforced concrete pylons reaching 90 metres (300 ft) in height; the maximum span was 210 metres (690 ft). It featured diagonal cable stays, with the vertical trestle-like supports made up of sets of Vs, one set carrying the roadway deck, while the other pair of inverted Vs supported the top ends of two pairs of diagonal stay cables.[ citation needed ]
The viaduct was officially opened on 4 September 1967 in the presence of Italian President Giuseppe Saragat. [12]
The bridge had been subject to continual restoration work from the 1970s due to an incorrect initial assessment of the effects of creep of the concrete. [13] This resulted in excessive deferred displacement of the vehicle deck so that it was neither level nor flat; at the worst points, it undulated in all three dimensions. Only after continual measurement, redesign, and associated structural work was the vehicle deck considered acceptable, approaching horizontal by the mid-1980s. [14]
In a 1979 report, Morandi himself said "I think [sic] that sooner or later, maybe in a few years, it will be necessary to resort to a treatment consisting of the removal of all traces of rust on the exposure of the reinforcements, to fill the patches, with epoxidic style resins, and finally to cover everything up with elastomers of very high chemical resistance". [6]
In the 1990s, the tendons (the steel wires, cables, and threaded bars, designed to produce the bridge's prestressed concrete) on pillar 11 appeared to be most damaged. [9] About 30% of the tendons had corroded away. The load of the bridge was 7,000 kg (15,000 lb) per tendon, whereas the tendons were originally capable of carrying 15,000 kg (33,000 lb).[ citation needed ] [15] A single truck can weigh as much as 44,000 kg (97,000 lb). [16] As of the collapse of the bridge, only pillar 11 had been internally inspected in the 1990s, showing severed and oxidized strands. [17] From 1990 onward, the easternmost pillar 11 had its stays strengthened by flanking them with external steel cables. [18] [19] Pillar 10 had the stays at the top strengthened with steel sheathing in the 1990s. [20] Following the collapse, many questions have been raised about the stays. [21] Morandi's similar [22] bridge in Venezuela suffered one or more stay cable failures in 1979/1980, with collapse imminent. [23] [24] [25] [26] [27]
The minister of infrastructures and transport in charge until 1 June 2018, Graziano Delrio, was informed multiple times in the Italian parliament during 2016 that the Morandi bridge needed maintenance. [28] [29]
In 2017, a confidential university report in Genoa noted severe disparities in the behaviour of the stays of the pillar 9, which would collapse. [17] The minutes of a February 2018 government meeting report that resistance and reflectometry measurements indicated an "average" reduction of the cross-section of the tendons of 10 to 20%. [30] [31] A crack in the road had appeared at least 14 days before the collapse, near the southeastern stay of the subsequently collapsed pillar 9. The crack may have been an indication that the stay had stretched. [32] [33] At no point was a suggestion made to reduce the load on the bridge. [30] Traditionally, bridges were designed for a 50-year lifespan; [23] the bridge failed just under 51 years after its opening.
On 3 May 2018, the Autostrade company had announced a call for tenders for a structural upgrade of the viaduct to the value of €20,159,000, with a deadline of 11 June 2018. The work on the reinforcement of the stays on pillars 9 and 10 would have needed to be finished within five years. [34] [35]
Workers were installing new heavy concrete Jersey barriers on the Ponte Morandi before it collapsed, reducing the already low-compressive prestress on the concrete of the stays and increasing the loads. [10] [21] [36]
In 2017, Carmelo Gentile and Antonello Ruccolo of the Polytechnic University of Milan studied the modal frequencies and deformations of the stays of the bridge. [17] On pillar 9, they could identify only four global modes, and the deformations of two of these identified modes were not fully compliant. [37] Modal frequencies were more than 10% different, specifically on the southern stays. [31] [38] In pre-stressed concrete beams, such a difference could represent the entire effect of the non-linear pre-stresses. As little as a 2% shift could represent severe damage. [39] [40] The prestress in the Ponte Morandi was characterised as relatively small from the start. In contrast, with bare tendons, which are relatively under-constrained like the strings in a piano, the effect of prestress is dominant in determining the resonant frequency. Other than prestress, changes in geometry, such as corrosion in the tendons, could impact the resonant frequency. The effects would be reduced by the composite nature of the stays when observing global modes. [41] Gentile had performed similar modal analyses on pillar 11 in the 1990s. [42] Other related methods were applied on the stays of Ponte Morandi in the 1990s, such as reflectometry, which was able to measure the tension, but not strength of the tendons. [41] [43]
By the mid-2000s, the A10 route through Genoa and over the bridge had become highly congested. The city council requested proposals for improvement of traffic flow through Genoa, with the Autostrade company in 2009 proposing the "Gronda di Ponente" project to improve flow, by moving traffic to a newly built Autostrada interchange system located to the north of the city. As part of the initial study and report, the Autostrade company measured that the bridge carried 25.5 million transits a year, with traffic having quadrupled in the previous 30 years and "destined to grow, even in the absence of intervention, by a further 30% in the next 30 years".
The study highlighted how the traffic volume, with daily queues at peak hours joining the Autostrada Serravalle, produced "an intense degradation of the bridge structure subjected to considerable stress", with the need for continuous maintenance. [44] The study showed that, in the option for improving what was termed as the "low gutter", it would be more economical to replace the bridge with a new one north of its current location, and then to demolish the existing bridge. [45] [ failed verification ]
On 14 August 2018, around 11:36 local time (09:36 UTC), during a torrential rainstorm, the span around pillar 9 of the Ponte Morandi collapsed and the vehicles on it fell into the Polcevera river. [46] [47] Forty-three people were confirmed dead and 16 injured. [48] [49] The disaster caused a major political controversy about the poor state of infrastructure in Italy and raised wider questions about the condition of bridges across Europe. [50] It was later decided that the bridge would not be repaired, but demolished. Demolition began in February 2019 [51] and was completed on 28 June 2019. [52] [53] Construction on the replacement began on 25 June 2019, and it was completed in the spring of 2020. The Genoa-Saint George Bridge was inaugurated on 3 August 2020. [54]
The Millau Viaduct is a multispan cable-stayed bridge completed in 2004 across the gorge valley of the Tarn near Millau in the Aveyron department in the Occitanie Region, in Southern France. The design team was led by engineer Michel Virlogeux and English architect Norman Foster. As of October 2023, it is the tallest bridge in the world, having a structural height of 336.4 metres (1,104 ft).
Prestressed concrete is a form of concrete used in construction. It is substantially "prestressed" (compressed) during production, in a manner that strengthens it against tensile forces which will exist when in service.
The General Rafael Urdaneta Bridge is located at the Tablazo Strait outlet of Lake Maracaibo, in western Venezuela. The bridge connects Maracaibo with much of the rest of the country. It is named after General Rafael Urdaneta, a Venezuelan hero of Independence who was born in Maracaibo.
Mundys SpA is an Italian holding company active in the motorway and airport infrastructure and mobility-related services industry, operating tolling services in 24 countries, including 11 for motorway and airport infrastructure concessions.
An extradosed bridge employs a structure that combines the main elements of both a prestressed box girder bridge and a cable-stayed bridge. The name comes from the word extrados, the exterior or upper curve of an arch, and refers to how the "stay cables" on an extradosed bridge are not considered as such in the design, but are instead treated as external prestressing tendons deviating upward from the deck. In this concept, they remain part of the main bridge superstructure.
Riccardo Morandi was an Italian civil engineer best known for his innovative use of reinforced concrete and prestressed concrete, although over the years some of his particular cable-stayed bridges have had some maintenance trouble.
The Autostrada A10 or Autostrada dei Fiori is an autostrada 158.1 kilometres (98.2 mi) long in Italy, passing through Liguria and connecting Genoa and Ventimiglia to France. It is a part of the E25, E74 and E80 European routes. It connects to the French A8 autoroute, which finishes in Aix-en-Provence.
Wadi el Kuf Bridge, is a bridge located 20 km west of Bayda, Libya. It is the second highest bridge in Africa.
The year 2018 in architecture involved some significant architectural events and new buildings.
Genoa is a city in and the capital of the Italian region of Liguria, and the sixth-largest city in Italy. In 2023, 558,745 people lived within the city's administrative limits. While its metropolitan city has 813,626 inhabitants, more than 1.5 million people live in the wider metropolitan area stretching along the Italian Riviera.
Ponte della Magliana is a motorway bridge in Rome (Italy). It crosses the Tiber between Pian due Torri and Via del Cappellaccio, linking the Quartieri Portuense and Ostiense, respectively on the right and on the left of the river.
It is currently part of a larger viaduct, which continues on the right bank of the Tiber towards the Colli Portuensi urban zone and the highway to the Fiumicino Airport and on the left one towards the EUR district, the Tre Fontane urban zone and Via Laurentina.
The Polcevera is a 19-kilometre (12 mi) river in Liguria (Italy).
This page is a glossary of Prestressed concrete terms.
Events during the year 2018 in Italy.
Danilo Toninelli is an Italian politician.
The bridge of Caprigliola was also known as the Albiano bridge, the Albiano Magra bridge or the Ponte di Albiano Magra.
The Genoa Saint George Bridge is a motorway viaduct that crosses the Polcevera river and the districts of Sampierdarena and Cornigliano, in the city of Genoa. It was designed by architect Renzo Piano.
The Tirantes Bridge is a cantilever spar cable-stayed bridge that crosses the Lérez River in the city of Pontevedra, Spain, linking the south bank to the north bank at the level of the city's Congress Hall.
On 14 August 2018, around 11:36 local time a section of the Ponte Morandi in Genoa, Liguria, Italy, collapsed during a rainstorm, killing forty-three people. The remains were demolished in June 2019. The replacement bridge, the Genoa-Saint George Bridge was inaugurated a year later.
Dr Maria Rosaria Marsico, senior lecturer in Structural Engineering at the University of Exeter, said: 'The bridge that collapsed today is part of the Polcevera Creek Viaduct in Genoa, Italy. It was built in a densely crowded urban area which is occupied by two railroad yards, large industrial plants and the Polcevera Creek. The bridge is known as Morandi Bridge from its designer, the engineer Riccardo Morandi.'
{{cite web}}
: CS1 maint: multiple names: authors list (link){{cite journal}}
: Cite journal requires |journal=
(help){{cite web}}
: CS1 maint: multiple names: authors list (link)