The Kingdom Tower in Saudi Arabia will stand 3,280 feet – one kilometre – tall upon completion. While uncertainty persists as to whether or not the skyscraper will ever become a reality, testing currently being conducted by engineers will at least determine if its construction is theoretically possible.
One of the biggest challenges in building the world's tallest skyscraper will be pouring of concrete thousands of feet above the ground. The challenge of pumping concrete so high up a single, pressurised pipe represents a massive engineering feat.
The developer has engaged Advanced Construction Technology Services (ACTS) to investigate the materials and process required. ACTS specialises in construction materials technology, particularly in the practical aspects of specifying concrete materials and methods, concrete production, putting concrete into place and getting the most out of concrete on a long-term basis.
The company will test the strength of different high performance concretes in conjunction with steel framing options. It is likely that around half a million cubic metres of concrete and approximately 80,000 tonnes of steel will be required for the skyscraper. Once the optimum materials have been determined, engineers will have to work out how to pour each floor on top of the preceding one, which will require further testing of methods for pumping wet concrete.
"ACTS will deploy special equipment to evaluate the rheological properties of concrete to ensure concrete will be pumpable to very high elevations," reported the Saudi Gazette.
The foundations of the tower will be 200 feet deep and will have to be able withstand salt water from the Red Sea, website Gizmodo reported, meaning that testing the materials must be the first item on the building agenda.
However, a similar technique was used to build the Burj Khalifa skyscraper, which set the world record for the highest concrete pumping.
A new, super high-pressure trailer pump was specifically designed for the Burj project. The pump’s frame and hopper were reinforced in order to withstand the enormous weight of the concrete mixtures.
Throughout the entire project, only high compressive strength concrete mixtures were used and pouring was only performed at night because of high temperatures during the day. Concrete was chilled at the plant prior to preparation and part of the water was replaced with shards of ice, allowing the concrete to be transferred at 82° Fahrenheit (28° Celsius), which is typical of night time temperatures in Dubai.
Other challenges the team will face include how to incorporate the vertical transportation systems and fire escapes required, which take up valuable occupiable space; how to reduce its overall weight to save costs; and how to ensure the tapering wing design is suitably aerodynamic in its shape to reduce structural loading due to wind speeds at higher altitudes.
Since the 1960s, engineers have primarily employed tubular designs devised by Bangladeshi-American structural engineer Fazlur Rahman Khan to build skyscrapers.
This engineering principle makes the buildings structurally more efficient and stronger and reduces the use of material to keep costs down while allowing the buildings to reach greater heights.
It has been quiet on the Kingdom Tower news front for a while, so reports of this testing phase casts a more positive light on its possible progress. Irrespective of whether the tower is ever built, the current phase of the project at least determine whether its construction is a theoretical possibility.
The proposed tower is expected to cost $1.23 billion and would be 568 feet (173 metres) taller than Dubai's Burj Khalifa tower.