M5 (Cape Town)

The M5 is an expressway in Cape Town, South Africa. It connects the northern suburbs (Milnerton) to Muizenberg in the south, and crosses both the N1 and the N2. For part of its length, from the N1 interchange to Plumstead, it is a limited-access freeway (motorway).

It begins at the Potsdam interchange at the N7 in the north; then proceeds southward and becomes a dual-carriageway at Blaauwberg Rd and is called Koeberg Road through this section. At the Koeberg Interchange with the N1, the M5 becomes a limited access motorway and is called the Black River Parkway. At the N2 interchange, the name changes to the Kromboom Parkway. Just south of the Ottery Road interchange, the M5 loses its motorway status and is a dual-carriageway as Prince Georges Drive. It terminates at the R310 (Baden Powell Drive) on the False Bay coast in Muizenberg.

The largest interchange on the M5 is the Koeberg interchange, connecting the M5 with the N1. The merging of lanes at this interchange used to result in multi-kilometer stop/start queues approaching the interchange on the M5.

In 2008, work began to upgrade the Koeberg interchange with elevated freeways joining the M5 and the N1. The elevated freeway from the N1 onto the M5 was completed in June 2010 in time for the 2010 FIFA World Cup, while the other direction was completed in November 2011.

At the end of 2011, Google maps street view of this interchange showed the progress of the work on the interchange in stages by combining images over time and connecting them underneath existing bridges. This enables the viewer to experience a form of virtual reality during multiple points in the construction phase.

The elevated freeways embody some innovative design features and principles. For example: The elevated freeways had to be built without disrupting the daily flow of some 200 000 vehicles. The existing roads and bridges had already used up the available land into which to expand. The intersection is hemmed in by a canal, railway reserve, power transformer, and industrial buildings etc. Thus the possibility of overlaying the existing structures with a bypass had to be envisioned. It had to be a system that could fit into the existing interchange. Oval reinforced concrete pillars with "T" pieces atop, standing on foundations supported by concrete piles, could fit into the spaces between existing roads and bridges. These could in turn support post-tensioned concrete "U" beam spans, cast on the ground and lifted into place by crane. The road deck would be cast on top of the "U" beams. Five beams between each "T" topped pillar allowing for a double lane road deck. The beams resting on each side of the "T" piece support, are connected to each other and the deck by a concrete end which resists lateral-flexing of the deck between-beams.

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Wikipedia