https://www.bbc.co.uk/news/world-europe-45183624
A motorway bridge has collapsed near the Italian city of Genoa, sending vehicles plummeting some 100m (328ft) to the ground and killing at least 11 people, local media report.
Actually, there are no certain hypotheses about the causes. The bridge has been being monitored by the owner (the motorway is a tolled road managed by a private company) and by an engineering service provider. They say that no critical clue has been observed so far. If it is true I wonder why the bridge was under strict monitoring. As far as I know there are 3 bridges only all around the world that uses the same buiding technology (one of them is in Venezuela: https://en.wikipedia.org/wiki/General_Rafael_Urdaneta_Bridge) and all af them showed some problems after just 20 years. In my opinion, the problem is related to the technology used (for ex. the "cables" seems to be in renforiced concrete than iron) as the sigle structural elements "works bad".
We will see. I believe that after the rescue operations the investigations will report some additional clues and information to clarify this very bad page for Italy.
I think bridge has worked for many years without any trouble. However the loading for which it was designed long back is same or different is to be ascertained? Secondly, the fatigue can be one of the reason over the years which along with serious weather conditions also lead to load combinations resulting into failure in the already distressed elements.
It is reported that bridge was constantly monitored for distress. As per the early reports,cavities and degradation in concrete specially at fixation points of the prestressed cable stays were strengthened from 1993 on wards which mean there were serious problems with the bridge at a later stage.
My guess only.
Actually, the ADT increased along the years. As you mentioned, two cables were completely replaced with iron ones. There was a project for the replacement of the other prestressed cables.
I agree with you, the fatigue can be one of the reason assuming the sudden collapse. In addition, that bridge was the first one in the world that used prestressed concrete. It has been a civil engineering challange for that time.
The Morandi Bridge, the "Brooklyn Bridge" was an announced tragedy. I hope it's not the bridge's fault.
For me it is very obvious a failure of the suspension cables. The method to cover them with concrete is no good solution. Corrosion can not be checked visually. Only advanced sensor systems like VCE/BRIMOS can find such damages. As it seems, the responsible engineers did not know such methods.
Thank you Georg. The investigations have started. Yes, the main suspects fall on the prestressed concrete cables.
There is not doubt about the encased stays in concrete were having problems as these were repaired in the past. Probably the monitoring agency has erred in estimating the dame to prestressed stays and also if suddenly the load due to storm increases then what will happen to already distressed portion of the bridge.
A detailed investigation report will reveal the real cause of failure and loss of life.
Likely culprit is corrosion caused by salt air hidden by concrete encasement of cables. ETR 470 north of Toronto built major concrete arch span bridges to last 99 years using epoxy-coated rebar. Very expensive up front but much lower life-cycle cost over 99 years. Toll owner/ operator and their engineers missed or ignored the earlier warning signs and failed to take the appropriate action, including closing the bridge to do necessary inspections and reconstruction. Shame.
Yes Daniel Dornan. Thanks. The problem is that operators (or goventaments if the case) did not consider mantainance costs Really shame!
Good question.. Please share me the best answer might you trust...
Regards…
The investigations are on going. They found massive degradation of pre-stressed cables (hided by the concrete). A part, the technical and important issues, also responsabilities from the government officers side are emerging (i.e. the ones who should have controlled the highway company activity). In fact, it is emerging that some officers have been consultant of the highway company (this is what national press reported)! But let's wait for the truth...
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