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Alfredo M Claussen

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Comments (2)

  • Comment on: Exclusive | Collapsed Italy bridge investigators find corrosion on main stay cables

    Alfredo M Claussen's comment 13 September, 2018 3:44 am

    @Donald Drysdale : I agree with your appreciation. Having read some pages of books written in the 1960's on Riccardo Morandi's bridges, it is quite obvious that many persons of that era were praising too much Mr Morandi's designs and skill.

    For me, it is a clear case of what I call "The Pygmalion Effect": when a creator of a given work becomes so enamored of his/her work that he/she ends up believing that his/her solution is not only the best, but the only way to go.

    Back in the 50's and 60's, too many engineers were dazzled with the then new possibilities of reinforced concrete construction. Morandi probably became obsessed with the intensive substitution of steel with the much less expensive concrete. One thing is now clear: Morandi could be brilliant,but his obsession with the (ab)use of concrete over steel carried him and their companions to propose what now seems a very bad idea: the use of bridge stays made of prestressed concrete instead of using steel tendons WITHOUT any concrete. I'm no Civil Engineer (actually I'm a Chemical Eng.) but I've known since school days that a long slender member that works in compression is limited by buckling. Now, Morandi obsession with prestressed concrete for the stays of his bridges was a very bad decision, because the stays are very long and slender, so much that their prestressing HAD TO BE VERY LOW (unless risking to bucke them with the prestressing!), which opens the real possibility of cyclic stresses to cause concrete micro cracks that allow the humidity to penetrate and corrode the steel cables, which are not accesible for inspection as they are buried inside the concrete. Your comment on the amazing lack of redundancy is spot on. It appears that Morandi was so convinced of his skill that he disdained the use of several stays instead of his approach: just four stays per tower. a single stay failure DOES bring the entire tower down. In addition to the designer (Morandi), those who praised him and became too enthusiastic about his designs are equally guilty of this disaster: read the many books published in the 60's that praise the designer too much and you can see how everybody contributed to his designs being admired so much that NOBODY felt the need to revise the concept. As of today (2018), at least three of Morandis bridges have failed: the Wadi El Kuf bridge in Libya has been closed since 26 October 2017 when the Security Directorate of the Green Mountain region in east Libya called on the security services to close down the bridge, following recent inspections that identified potential fractures. Surprinsingly, the war-torn Libyans were much more careful than the Italians!, the second Morandi's bridge in Venezuela also has its share of problems, and the third is the Genoa one where almost 40 people died because of the overconfidence of that famous designer, now deceased. All of those bridges are of the very same design: Prestressed concrete stays, too few stays (No redundancy), and all of them were (stupidly) judged as "Works of Art". So, in my humble opinion, you can add petulance to overconfidence in a bad from the start design. Finally, I will risk to forward a prediction: One of these days, one of the "marvellous" bridge designs of Santiago de Calatrava ( that are extremelly 'atractive' ) but absurd because those were designed to stretch the imagination, will come down, sooner or later. To design too fancy and Bizarre bridges is not only wasteful, but reliability suffers and failure mechanisms could be easily understimated. Bridges should NOT be artistic above being safe, reliable and functional.

  • Comment on: Exclusive | Collapsed Italy bridge investigators find corrosion on main stay cables

    Alfredo M Claussen's comment 12 September, 2018 4:59 am

    @Donald Drysdale : I agree with your appreciation. Having read some pages of books written in the 1960's on Riccardo Morandi's bridges, it is quite obvious that many persons of that era were praising too much Mr Morandi's designs and skill.

    For me, it is a clear case of what I call "The Pygmalion Effect": when a creator of a given work becomes so enamored of his/her work that he/she ends up believing that his/her solution is not only the best, but the only way to go.

    Back in the 50's and 60's, too many engineers were dazzled with the then new possibilities of reinforced concrete construction. Morandi probably became obsessed with the intensive substitution of steel with the much less expensive concrete. One thing is now clear: Morandi could be brilliant,but his obsession with the (ab)use of concrete over steel carried him and their companions to propose what now seems a very bad idea: the use of bridge stays made of prestressed concrete instead of using steel tendons WITHOUT any concrete. I'm no Civil Engineer (actually I'm a Chemical Eng.) but I've known since school days that a long slender member that works in compression is limited by buckling. Now, Morandi obsession with prestressed concrete for the stays of his bridges was a very bad decision, because the stays are very long and slender, so much that their prestressing HAD TO BE VERY LOW (unless risking to bucke them with the prestressing!), which opens the real possibility of cyclic stresses to cause concrete micro cracks that allow the humidity to penetrate and corrode the steel cables, which are not accesible for inspection as they are buried inside the concrete. Your comment on the amazing lack of redundancy is spot on. It appears that Morandi was so convinced of his skill that he disdained the use of several stays instead of his approach: just four stays per tower. a single stay failure DOES bring the entire tower down. In addition to the designer (Morandi), those who praised him and became too enthusiastic about his designs are equally guilty of this disaster: read the many books published in the 60's that praise the designer too much and you can see how everybody contributed to his designs being admired so much that NOBODY felt the need to revise the concept. As of today (2018), at least three of Morandis bridges have failed: the Wadi El Kuf bridge in Libya has been closed since 26 October 2017 when the Security Directorate of the Green Mountain region in east Libya called on the security services to close down the bridge, following recent inspections that identified potential fractures. Surprinsingly, the war-torn Libyans were much more careful than the Italians!, the second Morandi's bridge in Venezuela also has its share of problems, and the third is the Genoa one where almost 40 people died because of the overconfidence of that famous designer, now deceased. All of those bridges are of the very same design: Prestressed concrete stays, too few stays (No redundancy), and all of them were (stupidly) judged as "Works of Art". So, in my humble opinion, you can add petulance to overconfidence in a bad from the start design. Finally, I will risk to forward a prediction: One of these days, one of the "marvellous" bridge designs of Santiago de Calatrava ( that are extremelly 'atractive' ) but absurd because those were designed to stretch the imagination, will come down, sooner or later. To design too fancy and Bizarre bridges is not only wasteful, but reliability suffers and failure mechanisms could be easily understimated. Bridges should NOT be artistic above being safe, reliable and functional.