On August 14 at 11:30 AM local time, a viaduct in Genoa, a city in northern Italy—the Morandi Bridge—suffered a severe collapse. The accident has caused at least 39 deaths, 16 injuries, 12 of which are serious, and the number of missing persons is between 4 and 12. When the bridge collapsed, it was raining heavily, and at least 30 vehicles were driving on the bridge, including heavy trucks; at least 12 cars fell from a height of 45 meters.
Europe's First Concrete Cable-Stayed Bridge
The Morandi Bridge is the work of the late famous Italian civil engineer Riccardo Morandi.
The bridge is a three-tower prestressed concrete cable-stayed bridge with a total length of about 1.1 km. It has A-shaped frame towers supporting concrete-encased stay cables, combined with V-shaped supports below the bridge deck to form a sturdy arrangement, which is not common in cable-stayed bridges. The main spans of the bridge are 202.50-207.90-142.65 m (divided thus because the bridge crosses a river, railway, and industrial buildings), side spans 6×73.20 m, tower height 100.2 m, deck width 18 m. Construction started in 1962 and was completed in 1968; renovation was carried out in 2006. After the incident, the Italian public questioned the poor maintenance of the bridge, which could not handle the high traffic of 25 million vehicles per year. Some witnesses also said that the bridge was struck by lightning and shook before collapsing, but most people believe that lightning could not break the reinforced concrete bridge body, and instead pointed out that the bridge itself had structural problems. As early as the early 1990s, the cables on the bridge had to be replaced, and further repairs were carried out in 2016. At the time of the collapse, the bridge was undergoing extremely critical reinforcement work, so many questioned whether the construction was timely enough, but this claim was denied by relevant parties. In addition, many corroded and fractured parts were found on the bridge. Antonio Brencich, a professor in the Department of Architecture at the University of Genoa and a famous architectural engineer, had questioned the safety of the bridge many times as early as 2016, saying that the bridge had serious safety hazards and should be reinforced in time, otherwise it might collapse. Brencich also said, "Morandi built three bridges of the same type worldwide, and later stopped building them due to structural problems. The only bridge of this type in Italy is in Genoa. The other two are in Libya and over Lake Maracaibo in Venezuela (partially collapsed after a ship collision in 1964). The building materials of this type of bridge worldwide wear out very quickly. In the case of a sudden collapse, it is obvious that the steel cables supporting the overall structure were first pulled apart. So the problem lies in the steel. The tower collapsed because the steel cables could not bear the load." Li Yadong, a famous bridge expert and professor in the Bridge Department of Southwest Jiaotong University, introduced that the bridge's designer, Morandi, was known for his skill in building prestressed reinforced concrete bridge structures with unique styles. Overall, the beam bridges, arch bridges, and cable-stayed bridges designed by Morandi have a strong personal style. However, for cable-stayed bridges (including the collapsed one), the cable supports are too few (only one suspension point per half span), which leads to an uneconomical beam design; the use of prestressed concrete cable components (not the common cable structures of today) may have an anti-corrosion effect, but maintenance after cracking may be more difficult; X-shaped piers are usually impressive but cumbersome to construct. At present, rescue operations are still ongoing, and the remaining parts of the bridge are not excluded from the risk of further collapse. As for the cause of this accident, it can only be known after entering the site for investigation when conditions permit. The editor will also continue to follow up and bring timely reports.