The Nelson Mandela Bridge
21 July 2003Paris has its Eiffel Tower, New York its Statue of Liberty, Sydney its Harbour Bridge. On 20 July, Johannesburg opened the largest cable-stayed bridge in southern Africa. Who else to name it after but Nelson Mandela, the man who led South Africa across the apartheid divide?
Two years and R38-million in the making, the spectacular Nelson Mandela Bridge has emerged as a new landmark for Gauteng province, and holds out the promise of a rejuvenated Johannesburg inner city.
The 284 metre long bridge crosses over 42 operational railway lines in linking Braamfontein and the north of Johannesburg to Newtown in the heart of the city’s central business district, and is the centre-piece of a R300-million inner city renewal project driven by the province's economic development initiative, Blue IQ.
Already completed in Newtown are the first phase of the Mary Fitzgerald Square, situated in the heart of the Newtown Cultural Precinct, and the Metro Mall, a multi-modal transport and retail centre catering for 150 000 daily commuters. Work is under way on the construction of new on- and offramps from the M1 highway, to give direct access to Newtown for motorists from the north and south of the city.
On the other side of the Mandela Bridge, a separate R200-million initiative has been launched by the City of Johannesburg and private investors to regenerate Braamfontein as a centre of business and entertainment, incorporating the Johannesburg Civic Theatre and Wits University.
Together, the Newtown and Braamfontein developments will form a "cultural arc" linking the Newtown Cultural Precinct with another major Blue IQ project - the 95 000 square metre Constitution Hill precinct being developed in Braamfontein, which will include a new Constitutional Court; accommodation for the Constitutional Commissions and related commercial, retail, transport and hospitality facilities; a visitor's information and exhibition centre; and new museums, community facilities and recreation space.
At the centre of the cultural arc will stand the Nelson Mandela Bridge, carrying two lanes of traffic, two sidewalks for pedestrians and a cycle path, with a continuous toughened glass parapet to ensure pedestrian safety.
The asymmetrical dual-pylon cable-stay bridge is made up of a 66 metre north back span, a 176 metre main span and a 42 metre south back span, giving a total length of 284 metres.
The north pylon is 42 metres high and the south pylon 27 metres high, creating a delicate balance and an interesting visual appeal. According to Engineering News, the main span was built as light as possible, using structural steel with a concrete composite deck, while the heavier back spans were built from reinforced concrete to counterbalance the long main span.
The bridge "is supported on the largest pot bearings ever to be installed in South Africa," Engineering News reported. "The 1.5 metre diameter bearings, which have a capacity of up to 27 Mn, are designed to accommodate the large temperature movements of the bridge."
Approximately 4 000 cubic metres of concrete and 1 000 tons of structural steel were used to construct the bridge, with around 500 tons of reinforcing steel cast into the concrete.
SouthAfrica.info reporter
