Projects with a value less than R50 million
SMEC South Africa for V&A Waterfront Swing Bridge PROJECT TEAM
Client: V&A Waterfront Cape Town Consulting engineer: SMEC South Africa
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ridges and moving bridges within South Africa’s oldest working harbour, the V&A Waterfront, have become a memorable part of any visitor’s experience. The new 4 m swing bridge, in fact, replaced a smaller, much-
loved 2 m wide swing bridge built in 1997. However, with the further expansion of the Waterfront, the
number of people crossing the cut was increasing yearly. By 2016, the previous 2 m wide walkway was carrying 2.4 million people annually. To keep pace with the demand, a new wider bridge was commissioned. The challenge set by the client was: • The new bridge had to be as quick, efficient, effective and reliable as the existing one. • The construction cost had to stay within a tight budget. • The works had to limit disruption to the public, the V&A and the environment. The design team worked through various options for the new link and a swing bridge was still deemed to be the best solution in terms of the speed of operation and electrical energy needed to operate it. The bridge had to be capable of operating in wind speeds of up to 60 km/h, designed for impact by a vessel from both directions and swing free in such a way as to protect the mechanical equipment. The new swing bridge has a span of 40 m. The deck is cable-stayed with a single plane of four locked coil cables connecting to a central, upstand spine beam. The reclining pylon is in the continuity of the main central beam and its stiffness transfers the cable loads into the piled substructure. The steel with timber deck is rotated on a slewing bearing, which is stressed down on to a doughnut-shaped pile cap by 34 vertical Freyssibars. The bridge is supported on eight piles, positioned in a ring. The slew bearing and hydraulic motors are in a plant room, created by the pile cap ring. By forming the pile cap in this way, it was possible to house the mechanics within the depth of the foundations, reducing the required excavation depth and keeping the foundations above sea level. The bridge’s integrated form is simple and unique. It serves as an important link and is considered a positive landmark for both the V&A and Cape Town.
C E S A A o n E n g i n e e r i n g E x c e l l e n c e Aw a r d s 2 0 2 0
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