The most recognizable structures around the world all have their charms. We celebrate a few that show the breadth of the use of concrete.
The world is full of marvelous technical feats that push the limits of creativity. But most of these fascinating structures wouldn’t exist without the use of one of the most ubiquitous and versatile building materials. Concrete is an integral part of our surrounding landscapes, whether in road surfaces, dams or buildings. Even the architects and builders of the most impressive structures around the world do not hesitate to use it.
Christ the Redeemer
Location: Rio de Janeiro, Brazil
Built: April 4, 1922 – October 12, 1931
If you look up at the narrow peak of Mount Corcovado, you will see the imposing statue of Christ the Redeemer. The statue, which represents Jesus Christ, is made of reinforced concrete covered with a mosaic of thousands of triangular soapstone tiles and rests on a square stone plinth. It is the largest Art Deco style sculpture in the world.
Actual on-site construction of the structure did not begin until 1926, with construction of the pedestal and chapel. A scaffolding in the shape of an elongated figure was erected on this base, and workers were transported by rail up the mountain to assemble the steel mesh that would reinforce the concrete.
The statue has braved the elements, including several lightning strikes, since its completion in 1931. The designers even provided for ongoing maintenance by creating internal areas with access doors to various parts of the statue.
Quantity of concrete: 265 cubic meters (estimate)
Interesting fact: Due to the position on top of the mountain, the statue is prone to lightning and is hit about three to six times a year. Before the FIFA World Cup in 2014, lightning struck and broke one of the statue’s thumbs.
Three Gorges Dam
Location: Hubei, China
Construction site: December 14, 1994 – 2006
A concrete gravity structure with a straight crest, the Three Gorges Dam is 2,335 m long with a maximum height of 185 m. The dam allows the navigation of ocean freighters and generates hydroelectric power through the accompanying hydroelectric plant. It was also intended to provide flood protection, but the effectiveness on this is unclear and has been debated.
In addition to technical prowess, the dam also has lifts and locks to handle all transport vessels that use the Yangtze River. Normal cargo passes through the ship’s locks while passenger ships use the lifts, where the journey takes 36 minutes.
While the construction is indeed a feat of engineering, it has also been at the forefront of controversy: the construction of the dam has caused the displacement of at least 1.3 million people and the destruction of natural features and countless rare architectural and archaeological sites.
Quantity of concrete: 28 million cubic meters
Interesting fact: when the dam was built, 39 trillion kilograms of water from the Yangtze River accumulated behind it 175 m above sea level. Its very size changed the Earth’s moment of inertia , slightly slowing its rotation.
Location: Virginia, United States
Yard: September 11, 1941 – January 15, 1943
A symbol of military might, the Pentagon is the headquarters of the US Department of Defense and one of the tallest office buildings in the world. It was designed by architect George Bergstrom and built by contractor John McShain.
Bergstrom had to use a five-sided asymmetrical shape for its design due to the position of the existing roads on the site. And because the site is on the floodplain of the Potomac River, the ground conditions presented several engineering challenges.
A minimal amount of steel was used in the structure as it was in short supply during World War II. Instead, the Pentagon was built as a reinforced concrete structure, using 680,000 tons of sand dredged from the river, and a lagoon was created under the Pentagon’s river entrance. To minimize the use of steel, concrete ramps were built rather than installing elevators.
Architectural and structural design work for the Pentagon proceeded concurrently with construction, with initial drawings provided in early October 1941, and most design work completed by June 1, 1942. Construction work sometimes preceded construction. design, with different materials used from those specified in the plans. Pressure to speed up design and construction intensified after the attack on Pearl Harbor on December 7, 1941.
Quantity of concrete: 333,000 cubic meters
Interesting fact: There are enough telephone wires in the Pentagon to wrap around the circumference of the Earth 4.5 times.
Location: Dubai, United Arab Emirates
Worksite: January 6, 2004 – October 1, 2009
Towering over the city of Dubai stands the Burj Khalifa, the tallest freestanding structure in the world. Described as a “vertical city”, the tower rises 828m and has 160 habitable levels, more than any building.
Designed by American architect Adrian Smith and developed by local real estate firm Emaar Properties, the tower’s tallest reinforced concrete walls were pumped using 80 MPa high-strength concrete from ground level , with a staggering vertical height of 601 m. This shattered the previous pumping record on a 470m building on the Taipei 101 skyscraper in Taiwan.
Quantity of concrete: 330,000 cubic meters
Interesting Fact: The design of the building resembles the Hymenocallis flower, native to Central and South America. The central core emerges at the top and culminates in a sculpted spire.
Lake Pontchartrain causeway
Location: Louisiana, United States
Yard: January 20, 1955 – August 30, 1956
Lake Ponchartrain is a large saline lake and wetland in southeast Louisiana that connects to the Mississippi Strait, with New Orleans on its southern shore. This massive body of water covers 630 square miles (1,600 km2). As the area’s population grew after World War II, people began to consider ways to cross the lake to overcome the long travel time needed to get around it. It was then that a bridge construction project was born.
Indeed, the Louisiana Bridge Company built a fabrication plant near the north end of the lake, where the bridge would sit. From there, all the concrete parts of the roadway were poured, cured and assembled on site.
The structure of the bridge, approximately 38 km long, also includes extensive sections of prestressed concrete, made by pouring concrete around high-tensile steel cables which have been stretched under tension to increase their strength, making the stronger finished part.
Louisiana’s soft soils meant that piles had to be driven deep into the ground to provide sufficient support for the vast structure. The company used 1.37m wide prestressed concrete hollow cylinders for the piles – larger and stronger than those used in any previous project.
Quantity of concrete: 197,140 cubic meters
Interesting fact: The Bridge Police issue approximately 1,100 citations per month for traffic violations on the roadway, with all proceeds going to the parishes of St Tammany and Jefferson.
Location: Berlin, Germany
Shipyard: 1965 – October 3, 1969
The iconic sphere design you see atop Berlin’s Fernsehturm TV tower was inspired by the Soviet satellite Sputnik, demonstrating the influence of the space age and new technologies, with the cross-section resembling a rocket spatial.
The foundation work began on August 4, 1965 and was completed at the end of 1965. The concreting of the foot of the tower began on March 15, 1966. The concreting progressed rapidly, so much so that the 100 m mark was exceeded on October 4, 1966. Its was reached its final height on June 16, 1967.
Quantity of concrete: 7,900 cubic meters for the well
Fun Fact: If you dine at the TV Tower, you’ll end up in a revolving restaurant. It takes 30 minutes to do a full rotation and get a 360 degree view of Berlin. To avoid emergencies, the kitchen is at the bottom of the TV tower, so each dish travels a few hundred meters with a special elevator.
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