In 2001, there was nothing off the coast of Dubai except for shallow gulf water. However, the city was becoming overpopulated quickly. To solve this problem, local real estate conglomerate Nakheel Properties used GPS precision to shape 94 million cubic metres of sand into a 17-frond palm tree-shaped island. Sixteen quarries throughout the UAE were dredged for rock, which forms a breakwater around the island to protect it from wind and waves. It took a decade for Palm Jumeirah to be fully completed, although residents began moving to the island in 2008. The trunk is made up of luxury hotels and malls; the fronds are lined with mansions. A six-lane underwater tunnel allows people to travel to the island from the mainland and the Middle East’s first monorail travels the length of the island. Two other islands are currently under construction.
Officially the tallest free standing building in the world, this skyscraper is 828 metre high and has 163 stories. The biggest challenge engineers faced were strong winds, so they conducted over 40 wind tunnel tests, not only to determine how the building would be affected, but to ensure the safety of the cranes used to construct it. Built in Dubai, UAE in 2010, the building changes width as it gets taller in a bid to “confuse the wind,” according to global engineering firm SOM, who created the structure. This means wind vortexes cannot form, as they encounter a new shape at each tier of the building. The building has been engineered to withstand earthquakes and other natural disasters.
Located in Osaka, Japan, this was the first airport to be built on an artificial island. The project was created as a solution to overcrowding, as the city was too small to fit an airport on the mainland. One of the biggest challenges engineers faced was the clay found in the seafloor they intended to build on – it retains too much water to be a reliable foundation. To combat this, engineers utilised 1.2 million sea drains, a new technique used for sea-based stabilisation. Tubes were driven deep within the clay, filled with millions of tons of sand, and then removed. The columns of sand still act as drains within the clay, to stop the foundation becoming saturated with moisture and moving. 48,000 concrete tetrahedrons were stacked upon the stabilised seabed, with each one weighing 181 tonnes. Nearby mountains were excavated and approximately 161 million cubic tonnes of earth were poured into the gaps. It took three years for the seawall and base to be completed, before construction could begin on the airport itself.
The airport is an architectural wonder, built to reduce environmental impact and save money – blade-like deflectors line the ceiling, channelling air through the building and acting as a passive air conditioning system. Completed in 1994, it took three years and saw over 10,000 workers contribute to its construction. The island is 4 kilometres by 2.5 kilometres and became the world’s most expensive civil engineering project, costing US $20 billion.
Tokyo Sky Tree
Engineers tasked with the construction of the 634 metre high-rise building faced many challenges while building Japan’s tallest building. They had to take into account not only the typhoons that strike Tokyo every summer, but also potential earthquakes as it is built on an active fault. Structurally, it features a reinforced concrete central column, which is separate from the outside steel frame – an adaptation of the design often seen in pagoda temples. Traditional Japanese building technique shinbashira was utilised, which sees the central column reduce sway by counterbalancing seismic waves.
This 50.5 kilometre tunnel features the longest undersea portion in the world, coming in at 37.9 kilometres. Completed in 1994 after six years of construction, it cost approximately US $21 billion and required much problem solving from engineers. For example, they needed to ensure passenger safety, in case of a fire within the tunnel. So, engineers constructed a third, smaller tunnel in between the two full-sided tunnels, to act as an escape route during emergencies. There are also a number of passages that allow the trains to cross-over onto the other track. Eleven boring machines were used to dig the tunnel, collectively weighing over 12,000 tonnes – each one was as long as two football pitches.
Construction saw collaboration between British and French engineers, who had a competition to see who could reach the centre of the tunnel first: the British won. 13,000 workers were employed at the height of construction, and 10 people were killed while building the tunnel. The average depth of the tunnel is 50 metres below sea level, with the lowest point 75 metres down. The Channel Tunnel was included in the American Society of Civil Engineer’s “Seven Wonders of the Modern World” list.
The French originally started this project back in 1880; however they failed because of poor design and high mortality from diseases such as yellow fever and malaria. So, the US took over and redesigned the endeavour in 1904, officially completing the project in 1914. Measuring 77 kilometres, this canal connects the Pacific and Atlantic oceans, allowing easier passage for ships. There were many challenges for engineers to overcome, such as the landmass being above mean sea level due to mountainous terrain, dense jungle, removing rocks and soil, and differences in tides. The Europeans believed canals should be built at sea level; however this would have involved much excavation and cost millions of dollars more. The Americans decided to utilise locks, which would raise and lower ships into the placid waters of the canal. Dams and spillways meant the water in this canal was better regulated than a strait in between two bodies of water, mitigating the issues brought on by the differences in tides.
At 343 metres high, the Millau Viaduct is the world’s tallest bridge – it’s even taller than the Eiffel Tower. 18,000 tonnes of concrete were used to build its seven piers and the bridge cost a total of US $524 million to construct. The biggest marvel of this bridge is the short construction span of only three years from 2001-2004; builders were placed under enormous pressure to build it in less than four years; otherwise the French government would fine them US $30,000 per day. The bridge spans 2460 metres from France to Spain and carries between 10,000 and 25,000 cars per day.
Grand Canyon Skywalk
This glass bridge allows tourists to walk out onto thin air, 1219 metres above the Colorado River in the Grand Canyon. Its construction required over 453,000 kilograms of steel and 37,000 kilograms of glass to complete, with the total cost coming to US $40 million. Engineers had to undergo rigorous testing to ensure the structure could withstand the strong winds that come through the canyon; it has been designed to absorb vibrations. The foundation consists of eight support beams and the skywalk was assembled onsite, with the welding of the bridge taking four months to complete. A manipulator was designed to lift the 46 glass panels, each weighing 816 kilograms, into place. Three tuned mass dampers, which were specifically calibrated to meet the wind and weight requirements, were placed inside the horseshoe frame to make the bridge structurally sound.
Venice Tide Barrier
Despite construction beginning in 2003, this barrier is not yet complete. However the last of the giant floodgates designed to protect Venice from rising sea levels were built by a Croatian engineering firm earlier this year. In total there will be 78 gates forming four barriers at the three lagoon inlets of Lido, Malamocco and Chioggia. Each gate weighs 272 tonnes and measures 30 metres wide by 20 metres high, and five metres thick. The Electromechanical Experimental Module (abbreviated to MOSE in Italian) consists of over 18,000 tonnes of built-in steel, and is expected to have a 100 year lifespan.
Engineers have been faced with a number of challenges during this project’s construction, such as lowering the 23,000 tonne foundation into a lagoon. MOSE’s purpose is to only be deployed when it is necessary to do so; it will not stop tidal flow into the lagoon or cut Venice off from the ocean. The moveable barriers will sit beneath the lagoons surface during calm weather, allowing the gates to fill with water. However, when the tide rises, the water will be pumped out of the gates and replaced with air, so they rise to the surface and form a barrier capable of stopping water surges as high as 2.7 metres. This project will cost approximately US $6.5 billion in total.
The world’s second-most powerful dam is located on the border of Brazil and Paraguay on the Paraná River. It was constructed in 1984, as a solution to projected energy crisis in Brazil due to its rapid population growth. The government decided to utilise the vast expanse of water surrounding Brazil and turn it into hydroelectricity. The dam took seven years to construct and provided jobs to 40,000 construction workers during this time. It generates enough energy to service 93% of Paraguay and 20% of Brazil.
The most challenging part of this project for engineers was changing the course of the Paraná River before construction could begin. It took three years for them to carve a 2 kilometre long, 91 metre deep channel for the river to divert through – fifty million tonnes of earth and rock had to be moved in the process. The dam wasn’t to be supported by any physical or natural features, so it had to weigh at least 61 million tonnes to withstand the water pressure, which was estimated to be the equivalent of 4000 bulldozers.
The world’s longest railroad took 25 years to construct. Completed in 1916, the Trans-Siberian Railway spans Russia from east to west for 9,198 kilometres; even today it’s the only way to cross the country, aside from flying. The idea was conceived by Tsar Alexander III; however the majority of its construction took place during Tsar Nicholas II’s reign, and stemmed from the fear of losing trade prospects. 90,000 labourers were contracted and the railroad was constructed simultaneously from both the west (Moscow) and the east (Vladivostok), working towards the centre. Challenges faced were the extreme weather conditions and the use of primitive hand tools, such as shovels, wheelbarrows, saws and axes to complete the labour. Budget constraints meant engineers avoided commercial centres, narrowed foundations and put down a reduced number of sleepers per kilometre. 12 million railroad sleepers were placed during construction and 100 million cubic metres of rock was moved. Line electrification began in 1929, but wasn’t completed until 2002.
Today, 30 per cent of Russia’s exports are transported via the railroad and trains carry an average of 250,000 containers to Europe each year. Not only does it link Moscow to Vladivostok, but has branching lines to China, North Korea and Mongolia. The 8 day journey spans 87 cities, 16 rivers and 8 time zones.
The tallest elevator in the world is located in the side of a cliff in China’s Wulingyuan scenic area. Constructed between 1999 and 2002, the Bailong Elevator’s shafts and tunnels were carved from a quartz sandstone column in the heritage-listed area, despite protests from environmentalists. Made of glass, it offers dizzying views to passengers, as it carries them 326 metres up the sandstone column to the top of a mountain range. 154 metres of the lift are embedded into the column, and the remaining 172 metres are set into exposed steel and other components. The journey takes just under two minutes, with lift cars running at three metres per second, taking up to 50 passengers at one time. Earthquake detectors are fitted into each car, to allow for a quick evacuation in case of an emergency.