The largest clock in the world. With a face size of 43 meters diameter, the Dokaae Clock is the largest clock in the world. Over 400 meters above the ground it is visible in all districts of Mecca, from more than eight kilometres away and is a breath taking addition to the Holy City.
The clock tower is a masterpiece of engineering and design having been developed by a team of specialists from Europe and all around the world.
As the leading supplier of large composite components, PCT was chosen to take on the challenge of building the upper 370 metres of cladding as well as the clock faces, all of which had to be designed in lightweight composites due to the fact that they had to be lifted nearly 400 metres into the air to be positioned.
The overall height of the tower is 601 metres, making it the second tallest tower in the world, second to the Burj Khalifa, Dubai.
The facade of the clock is made of 60,000m2 of advanced composite material. This is one of the largest applications of composite materials.
The clock has four faces, two of which measure 43 metres in diameter.
Each composite panel is covered with 98 million glass mosaic tiles and gold leaf.
Two million LED lights are then embedded into the facades and clock faces to light up the faces by night.
Due to weight restrictions, the clocks hands are self-supportive carbon fibre structures. The minute hands are 22 metres long and the hour hands are 17 metres long.
For maintenance the clock hands are fully accessible. Each clock hand weighs just 6 tonnes.
On approval and once all components were finished, they were shipped to Mecca for installation.
425 meters above the ground, one of the seven tower cranes levers the giant clock hands into position.
The call to prayer from the Holy Mosque will broadcast live from the top of the Clock Tower over a specially developed loudspeaker system. This call can be heard within a radius of up to 7 km from the tower.
As the call to prayer sounds, the top of the tower will be illuminated with 21,000 white and green sparkling lights. These dazzling lights are visible up to 30km from the tower, signifying the start of prayer. This signal is useful for the hearing-impaired and those at a great distance from the Mosque.
The composite crescent built from carbon and glass fibre stands at the very top of the tower and measures 23 metres in diameter, making it the largest crescent ever built.
Engineers designed the crescent so that it is self-supportive and therefore requires no steel structure, this helps to keep the weight as low as possible. The crescent is built in a similar way to a sailing boat with structural composite frames, like bulkheads inside a yacht.
Inside the crescent there is a fully contained living space that consists of 4 floors that are used for prayers and resting, 2 floors house an office, kitchen and bathroom.
Related links :
Gulf Construction May 2012
Composites Technology October 2010
Emirates Construction December 2010
Construction Week Online May 2011
JEC Composites May 2011
Reinforced Plastics May 2011
Construction Week June 2011
Time-lapse installation of the 1:1 scale mock-up of the quarter clock, Dubai. UAE.