How safe is SA's Morandi bridge?


The designer of the Genoa viaduct that catastrophically collapsed in August also had a hand in several South African bridges, including the one that spans the Storms River.

Storms River Bridge

After the recent catastrophic collapse of Genoa’s Ponte Morandi, killing more than 60 people, Noseweek has discovered that the bridge’s reknowned designer, civil engineer Professor Riccardo Morandi, also designed South Africa’s most famous bridge that spans Storms River on the Garden Route.

Although distinctly different in design from the Genoa bridge, known as the trademark Morandi design, the South African Roads Agency Ltd (Sanral’s) bridge Network Manager, civil engineer Edwin Kruger said they were “fully aware” of Morandi’s design involvement in the Paul Sauer Bridge, now better known as the Storms  River Bridge.

But, he said, drawing a like-for-like comparison with Genoa’s  Ponte Morandi would be wrong: “They are entirely different types of bridges.”

Ponte Morandi, which collapsed in August

“The Genoa bridge was a cable-stayed bridge, one of a series built across the globe that were characterised by the use of pre-stressed concrete in pylons and decks. The Paul Sauer Bridge is an arch bridge, made in two parts and then fitted together covering a distance of 100 metres, 123 metres above the river. In any event, as in most cases, there isn’t a single designer to a bridge, so making face- value comparisons is too simple,” said Kruger.

There was no need for concern, Kruger said, as all South African bridges under the jurisdiction of Sanral were on regular maintenance schedules, checked every five years, and that the Paul Sauer Bridge had already twice undergone expansion and rehabilitation programmes in the late eighties and mid 2000s. 

The bridge, completed in 1956, was built by Concor Construction. There had been a bit of drama: the bridge was built with a half-arch on each side of the ravine. When completed, the two halves were then to be lowered, hopefully to meet and lock exactly in the middle. According to a website, www.artifacts.co.za the onsite engineer, Bruno Desirello quipped that he would “commit suicide” if they didn’t.

On the day the two half-arches were lowered from either side of the canyon, they did not fit. Desirello, in a panic, made a hurried phone call to Morandi in Rome, who told him to try again later in the day to allow for expansion and shrinkage. That afternoon they tried again and the two halves slotted perfectly together, to a loud cheer and to Desirello’s great relief.

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Submitted by : Elio Boezio of PORT ELIZABETH on 2018-09-21 22:48:39
I rise on a technical point, M'lud: there were, in fact, FOUR half-arches: two on each side, lowered in pairs. I was there. Okay, I was only five years old - but I could count to four. And I have pictures.

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