Steel ties that bind nations: New bridge will span the Red Sea
An accord between Saudi Arabia and Egypt to bridge the Red Sea was the keynote event of King Salman’s visit to Cairo, but behind the headlines a story of engineering ambitions and deepening political relations was unfolding.
It was an announcement that generated headlines around the world. During his recent five-day visit to Egypt, King Salman bin Abdulaziz Al Saud, the monarch of Saudi Arabia, announced that a bridge would be built to span the Red Sea.
“I agreed with my brother His Excellency President Abdel Fatah al-Sisi to build a bridge connecting the two countries,” the king announced during a speech following his award with the Order of the Nile, Egypt’s highest state honour.
“This historic step to connect the two continents, Africa and Asia, is a qualitative transformation that will increase trade between the two continents to unprecedented levels.”
As a gesture of gratitude, the Egyptian president suggested that the crossing should be named the King Salman bin Abdel Aziz Bridge.
“Saudi Arabia to build a 30-mile bridge across Red Sea to Egypt” heralded the London-based Daily Mail, while The New York Times discussed the project in the context of 17 investment deals and other agreements worth around US$1.7 billion (Dh6.24bn) which included plans for a university, homes, a power plant in South Sinai and a five-year, $22bn oil deal.
None of these measures however, have attracted as much attention as the decision, made by the Egyptian cabinet, to transfer two arid but strategically important islands at the mouth of the Gulf of Aqaba, Tiran and Sanafir, to Saudi custody.
News of the territorial handover came in an Egyptian announcement, which said a technical investigation of the countries’ maritime boundary had clarified the status of the islands, located between the Egyptian tourist resort of Sharm El-Sheikh and the Ras Alsheikh Hamid peninsula in Saudi Arabia.
The deal on Tiran and Sanafir has generated enormous amounts of comment and speculation but on a very practical level their fate is intimately connected with the proposal for a bridge crossing the Red Sea and it is not the first time that a bridge has been proposed for the narrow waterway known as the Strait of Tiran.
In 2012, the Egyptians discussed plans for a $3bn, 32-kilometre causeway across the Strait between Ras Nassrani in Egypt and Ras Hamid in northern Saudi Arabia. But then, as now, there was no explanation about how such a crossing might work.
The Strait of Tiran, which flows between the Egyptian mainland and Tiran Island and provides the only navigable channel for large ships sailing to and from ports in Jordan and Israel, is part of a 19 kilometre-wide bottleneck that separates the Gulf of Aqaba from the Red Sea.
It contains a series of coral reefs, popular with divers, and two smaller channels that act as separate lanes for north and southbound traffic.
However, as engineer Mike Tapley explains, constructing a traditional causeway over such a strait would not only make it impassable, but is also likely to be technically impossible.
“The area around the Strait of Tiran is almost 300 metres deep, [so] there’s no way that you could put a [bridge-supporting] pier into a location like that, which means that you would have to put a span over any depth of that kind. The alternative would be a floating bridge, but when you’re dealing with shipping lanes that would be impossible,” says the lead bridge designer in Asia with international engineering consultancy Aurecon. “If you’re talking about depths of more than 100 metres then piers become impossible.”
In this situation, a bridge designer then has to choose which type of bridge will be required.
“There are two different types of long-span bridges, one is the suspension bridge and the other is the cable stay bridge. The bridge with the longest span in the world at the moment is the Akashi Kaikyo suspension bridge in Japan, with a central span of just under two kilometres,” explains Mr Tapley, who has worked on two of the most complex cable-stayed bridges in the world: Stonecutter’s Bridge in Hong Kong and the six-lane Rio-Antirrio Bridge in Greece. Both employ steel cables to support their concrete and steel decks.
“Stonecutter’s bridge is a cable-stayed bridge with a span of a kilometre and the big feature of that was that it is over one of Hong Kong’s major shipping lanes,” Mr Tapley explains.
“If you are dealing with some of the biggest container ships, you need a clearance above sea level of 75 metres, which means that the approach spans have to be long and quite high, so if you’re close to land you end up with large viaducts going over the land, which can have a significant impact on the local environment.”
It is the potential impact of any bridge on the Red Sea’s environment, and in particular its coral reefs, that concerns Christian R Voolstra, associate professor of marine science at King Abdullah University of Science and Technology in Thuwal, Saudi Arabia.
“You find coral reefs across the sea’s entire coastline so wherever you build this bridge, coral reefs will be affected. The Great Barrier Reef may be the largest reef system by area, but the Red Sea contains the longest connected coral reef system in the world,” the scientist explains.
“There’s particularly high biodiversity in the Red Sea and it’s also a very warm sea, so from a scientific perspective it’s very important because it mimics future ocean conditions,” explains the scientist, who has been studying coral reef ecosystems and biodiversity in the Red Sea since 2009.
“I think it’s one of the few places on this planet where you can study ocean life in a future ocean environment. We can basically go into the sea to study adaptations that might happen in response to environmental change scenarios in other places in the future. That’s why it’s so important to protect its biodiversity.”
Professor Voolstra admits that even when dealing with habitats as unique as those in the Red Sea, it is almost impossible to trump economic arguments with environmental imperatives. However, rather than opposing a crossing, he believes that a bridge might offer an important opportunity.
“Projects like this will always happen and they present a chance to do things right and to act as a model for future construction,” he hopes. “There are always ways to do things better.”
Published: April 17, 2016 04:00 AM