Construction

(Source: Sanfrancisco.cbslocal)

The South Korean company, Samsung Engineering & Construction, handled the construction aspect of the grand tower Burj Khalifa; said company also did the work on the Petrona Twin Towers and Taipei 101.

Samsung Engineering & Construction built the tower in a joint venture with Besix from Belgium and Arabtec  from UAE, with Turner as theProject Manager on the main construction contract.  Under UAE law, the Contractor and the Engineer of Record, Hyder Consulting, is jointly and severally liable for the performance of Burj Khalifa.

The primary structure is reinforced concrete; with over 45,000 m3 (58,900 cu yd) of concrete, weighing more than 110,000 tons used to construct the concrete and steel foundation, which featured 192 piles.  Each pile is 1.5 meter diameter x 43 m long, buried more than 50 m (164 ft) deep. 

The construction were able to use 330,000 m3 (431,600 cu yd) of concrete and 55,000 tonnes (61,000 short tons; 54,000 long tons) of steel rebar, and construction took 22 million man-hours. A high density, low permeability concrete was used in the foundations of Burj Khalifa. A cathodic protection system under the mat is used to minimize any detrimental effects from corrosive chemicals in local ground water.  

In May 2008 concrete was pumped to a then world record delivery height of 606 m (1,988 ft),the 156th floor. Three tower craneswere used during construction of the uppermost levels, each capable of lifting a 25-tonne load.The remaining structure above was constructed of lighter steel.

Burj Khalifa is highly compartmentalized, with pressurized, air-conditioned refuge floors located approximately at every 35 floors where people can shelter on their long walk down to safety in case of an emergency or fire.

Special mixes of concrete were made to withstand the extreme pressures of the massive building weight; as is typical with reinforced concrete construction, each batch of concrete used was tested to ensure it could withstand certain pressures.CTL Group, working for SOM, conducted the creep and shrinkage testing critical for the structural analysis of the building.

The consistency of the concrete used in the project was essential. It was difficult to create a concrete that could withstand both the thousands of tonnes bearing down on it and Persian Gulf temperatures that can reach 50 °C (122 °F).

(Source: ckdp.ca)

To combat this problem, the concrete was not poured during the day. Instead, during the summer months ice was added to the mixture and it was poured at night when the air is cooler and the humidity is higher. A cooler concrete mixture cures evenly throughout and is therefore less likely to set too quickly and crack. Any significant cracks could  put the entire project in jeopardy.

The unique design and engineering challenges of building Burj Khalifa have been featured in a number of television documentaries, including the Big, Bigger, Biggest series on the National Geographic  and  Five channels, and the Mega Builders series on the Discovery Channel.