The World's Biggest Clock

The World’s Biggest Clock

What is it about clocks as a way of showing off?

On the personal scale, the absurdly expensive wristwatch has long been considered an acceptable, even tasteful way of showing off wealth.

At the other end of the scale is the desire to own the world’s biggest clock. For example, the Grozny City Tower clocks, which were mentioned here in another context, are often said to be among the largest in the world, a factoid sometimes corrupted to ‘the largest in the world.’ (And we confess that we bought into that false factoid and repeated it.)  In fact, the two clock faces, at merely 13m in diameter, rank only about #8 in the world.

The largest clock faces belong to the Dokaae Clock on the central tower of the Abraj al Bait development in Mecca, Saudi Arabia. The tower, including its golden crescent finial, stands 607m (1991 ft) tall, making it the second tallest building in the world. Two of its four clock faces are 43 m (141 ft) tall. That’s about as tall as a 12-story building. The minute hands are 23m (75 ft) long, about as long as a short-course competition swimming pool.

The clock faces, the hands, the crescent above it, in fact, nearly the entire top 1/3 of the tower, are composite cladding.

The clock faces are composed of 60,000 m2 of “advanced composite material” according to the website of Premier Composite Technologies, the fabricator for the tower project. Composites were chosen in part because of the light weight, making it easier to install the panels 400m above the ground. Nonetheless, the composite panels are covered in 98 million glass mosaic tiles and gold leaf. (In addition, there are 2 million LED lights embedded into the facades and clock faces.)

The clock long, slender hands, which had to be self-supporting and withstand high wind loads, are made from carbon fiber composite with a structural foam core. Each weighs 6 metric tons.

The giant golden crescent at the tower’s apex is also a self-supporting composite structure, a combination of glass fiber and carbon fiber, with no steel. Its design is similar to sailboat construction. At 23 m (75 ft) in diameter, it is said to be the largest crescent of is type ever constructed. Inside the crescent of a 4-story living space used for prayer and for resting, including 2 floors of office, kitchen and bathroom facilities.

The architects were SL-Rasch, of Stuttgart, Germany, with engineering and composite materials were supplied by Gurit, Wattwil, Switzerland.

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