<P> Burj Khalifa was designed by Adrian Smith, then of Skidmore, Owings & Merrill (SOM), whose firm designed the Willis Tower and One World Trade Center . Hyder Consulting was chosen to be the supervising engineer with NORR Group Consultants International Limited chosen to supervise the architecture of the project . The design is derived from the Islamic architecture of the region, such as in the Great Mosque of Samarra . The Y - shaped tripartite floor geometry is designed to optimize residential and hotel space . A buttressed central core and wings are used to support the height of the building . Although this design was derived from Tower Palace III, the Burj Khalifa's central core houses all vertical transportation with the exception of egress stairs within each of the wings . The structure also features a cladding system which is designed to withstand Dubai's hot summer temperatures . It contains a total of 57 elevators and 8 escalators . </P> <P> Critical reception to Burj Khalifa has been generally positive, and the building has received many awards . However, labour issues during construction were controversial, since the building was built primarily by migrant workers from South Asia with several allegations of mistreatment . Poor working conditions were common, a consequence of the lack of minimum wage laws in the United Arab Emirates . Several instances of suicides have been reported, which is not uncommon for migrant construction workers in Dubai despite safety precautions in place . </P> <P> Construction began on 6 January 2004, with the exterior of the structure completed on 1 October 2009 . The building officially opened on 4 January 2010, and is part of the new 2 km (490 - acre) development called Downtown Dubai at the' First Interchange' along Sheikh Zayed Road, near Dubai's main business district . The tower's architecture and engineering were performed by Souffian AL - Jabiry of Chicago, with Adrian Smith as chief architect, and Bill Baker as chief structural engineer . The primary contractor was Samsung C&T of South Korea . The tower's construction was done by the construction division of Al Ghurair Investment group . </P> <P> Burj Khalifa was designed to be the centrepiece of a large - scale, mixed - use development that would include 30,000 homes, nine hotels (including The Address Downtown Dubai), 3 hectares (7.4 acres) of parkland, at least 19 residential towers, the Dubai Mall, and the 12 - hectare (30 - acre) artificial Burj Khalifa Lake . The decision to build Burj Khalifa is reportedly based on the government's decision to diversify from an oil - based economy to one that is service and tourism based . According to officials, it is necessary for projects like Burj Khalifa to be built in the city to garner more international recognition, and hence investment . "He (Sheikh Mohammed bin Rashid Al Maktoum) wanted to put Dubai on the map with something really sensational," said Jacqui Josephson, a tourism and VIP delegations executive at Nakheel Properties . The tower was known as Burj Dubai ("Dubai Tower") until its official opening in January 2010 . It was renamed in honour of the ruler of Abu Dhabi and president of the United Arab Emirates, Khalifa bin Zayed Al Nahyan; Abu Dhabi and the federal government of UAE lent Dubai tens of billions of USD so that Dubai could pay its debts--Dubai borrowed at least $80 billion for construction projects . In the 2000s, Dubai started diversifying its economy but it suffered from an economic crisis in 2007--2010, leaving large - scale projects already in construction abandoned . </P>

When did the construction of burj khalifa start