Marvellous concrete creations – CN Tower
The CN tower stands in Toronto Canada, and is used as a communication and observation tower. The construction on the tower begun in 1973 and was completed in 1976. The three year project was taken on by 1,537 workers who worked on the tower 24 hours a day, 5 days a week until the towers completion. The original idea for the tower was a communication platform for the area of Toronto. The tower still serves this purpose, but is also used as an observation tower, tourist and public attraction, restaurant and ‘edge walk’ attraction for thrill seekers. The CN tower is actually the worlds 9th tallest freestanding structure! The CN tower has a weight of 130,000 tonnes making it stand super strong. So strong in fact, that to topple the tower over, it would take an unimaginable, 1,600km/h wind, says the architect of the tower, and in case you were wondering, no, this speed of wind certainly doesn’t exist.
Constructing the Tower
Over the CN towers 40 month construction, 53,000 cubic yards of
concrete were poured, resulting in a cost of 63 million Canadian dollars for the total cost of the project, an equivalent of 300 million today. At 553 metres tall, the tower made it into the Guinness World Records in 1976 as the world’s tallest freestanding structure. However its title has since been taken by various other buildings around the globe, and now comes in 9th in the list.
The CN tower actually became the tallest structure in Canada, before construction was even completed. All of the tower’s
concrete was mixed on site, and continuously poured daily by it’s enormous team of workers. Constructors used a hydraulic pressure powered slipform (mould) to pour the
concrete into. The slipform would rise gradually upwards, as concrete below hardened. The mould would also gradually decrease in size, as you can see by the towers curvy design.
