In April 2008, three trailer-mounted pumps reached the current world record for vertical concrete pumping. At the construction site of the Burj Khalifa, the world;s tallest building, concrete was pumped to a record height of 606 meters (m). A strategically designed concrete pumping system made the final conveying height a reality, as the concrete flowed through several stages up the 828-m tower.
The Pump Station
Preparations for the concrete pumping system began in early 2005. Three trailer-mounted concrete pumps were paired with a carefully engineered delivery line system. Four non-ballasted stationary placing booms and several truck-mounted boom pumps were added to support the system.
Image 2. Three trailer pumps were combined into one station to reach a record height of 606 meters. Extensive tests on the pump and delivery line were conducted on site. Horizontal pipelines simulated the pressure and friction based on the concrete mixture and data from other vertical-pumping applications.
A specially designed, high-pressure trailer pump was created specifically for the Burj Khalifa project. The pump\'92s frame and hopper were reinforced to withstand the forces of the concrete mixtures. The new pump also included valves and bearings adjusted for the predicted pressure, as well as a filter system.
The three trailer pumps were combined to create one pump station. The station pumped approximately 165,000 cubic meters (m3) of high-strength concrete during 32 months of operation.
Three of the trailer pump delivery lines were connected to three placing booms. The booms were secured on platforms of an auto-climbing formwork and stood on 16-m tubular columns for the tower's three wing sections.
The Concrete Mixture
Throughout the project, operators could only use high-strength concrete mixtures. The mixtures were only poured at night because of hot temperatures during the day. The concrete had to be chilled in the plant before preparation. Some of the water was replaced with ice, allowing the concrete to remain at 28 degrees Celsius as it was transferred to the site.
Plant personnel monitored and logged each batch of concrete. Temperature and viscosity were checked regularly before the concrete arrived at the pumps. Then, samples were poured to check pressure.
While developing the delivery line system, engineers considered wear behavior, compressive strength and flow path. Truck-mounted boom pumps placed the structure'2s 7,000-square-meter (m2) foundation. Two hundred concrete piles (1.5 m in diameter) support the foundation for the core tower, and 650 piles support the tower's wing sections.
Image 2. Three trailer pumps were combined into one station to reach a record height of 606 metersMore Records to Come
Burj Khalifa helped push Dubai into the international spotlight. As more projects come online ahead of Expo 2020 and other world events, the need for specialized pumping solutions to fit each project will become even more pressing. Burj Khalifa is just the beginning for growing urban centers in the Middle East and North Africa—including Jeddah, Saudi Arabia, the future home of the Kingdom Tower, which will reach a height of 1 kilometer.