King Abdullah Financial District (KAFD) is an unprecedented development that seeks to transform the Saudi capital Riyadh into a major hub for Middle Eastern business.
The CMA Tower, at its ultimate height of 385m, is arguably the stand-out structure of the near-50 skyscrapers rising from the ground at the site.
It will also be the centre piece of the KAFD’s Financial Plaza, which incorporates the five tallest structures in the development, including the CMA Tower, over a space of 50,000m2.
“It is a focal point and a landmark, visible from the North Gateway to the city,” said Ramzi Nawfal, regional director of Cyril Sweett, the project and commercial manager for the tower, in a presentation at last month’s Construction Week conference in Riyadh. He added that the structure will “eclipse” the present tallest structure, the 302m Kingdom Centre.
The slim tower with the wavy glass façade in the dreamy artist renderings will be just one of the distinctive features of the building that will house the Capital Markets Authority(CMA), Saudi Arabia’s chief financial regulator.
The tower’s inner total floor area is 185,000m2 and will contain commercial and corporate offices, a 450-seat auditorium, dining areas, leisure facilities, with the CMA occupying 28,000m2 in the top section.
The first stand-out fact about the tower’s construction is that it is built with no piles and no dampers. Nawfal says it was a challenge to build the four basement levels in the solid rock excavation. After that there was the challenge of dewatering – with the foundation level being the lowest in Riyadh, approximately 11,000m3 per day flowed into the area.
The second stand-out fact about the CMA Tower’s construction is that it contained the biggest raft pour ever in the Middle East. Supervised by Cyril Sweett, Saudi Binladin poured 13,000m3 of concrete over a 36-hour period last October.
The concrete pour was scheduled to last 42 hours, but was successfully completed within 36 hours,” says Des Pike, project director at Cyril Sweett.
“Throughout the operation, mobile truck mixers were arriving on-site at an average of one every 90 seconds, a significant logistical feat in itself.”
The pour followed a 30m-deep excavation and more than 4,000t of steel reinforcement. Texas-based Walter P Moore, the structural engineering firm for the tower project, had thought long and hard about the materials needed for the structural system, and conducted a carbon emissions study to help the building to achieve its target of a LEED Gold rating.
Despite the huge order for steel, the company calculated that this choice would cut by 40% the amount of concrete needed in the composite structure, reducing emissions by 30%.
The inner structure of the building is perhaps the most substantially different element, and combines many engineering feats to be able to securely support the lofty building above.
The core wall, usually square or elliptical in most towers, is instead nine-sided, and the inside of this core is split into three sections to create a Y-shaped concrete shape looking from above.