John Anderson considers the design of pedestrian bridges to be urban design because they form part of the urban landscape. John, together with his SMEC colleagues, Maja Wilson and Jonathan Adams, presented to SAICE members on Wednesday 18 September the recent addition to the V&A Waterfront’s landscape – the V&A Swing Bridge.

The previous V&A pedestrian bridge had reached its capacity and thus needed replacement. At 2 m wide, it carried up to 10 000 people per day in peak periods. The V&A’s key requirements for a new bridge were to ensure that disruptions were limited, and costs were minimised.

The design team undertook an options analysis and evaluated various options which ranged from constructing a second crossing, to widening the existing bridge, to a double swing or bascule bridge, but finally settled on a new single swing bridge with slew bearing.

Some of the operational design criteria that had to be met were:
- Opening and closing speed under normal operational wind speeds to at least meet the existing bridge (i.e. 90 s to open and 100 s to close);
- Designed to have 6 open and close cycles per hour for 12 hours per day, 7 days per week;
- Be capable of operating in winds of up to 60 km/h.

The design team faced a few challenges such as the tower slenderness, the integration with mechanics, and nose deflection and reaction.
The construction of the bridge comprised a substructure and a superstructure contract, which also had their own challenges such as minimising environmental impact, space constraints, and erection.