Describe how risks are reduced over the lifespan of a project such as this one.

Newtown, South Africa, is a suburb of Johannesburg that boasts a rich cultural heritage. As part of an attempt to help rejuvenate Newtown, the Nelson Mandela Bridge was constructed to link it to important roads and centers of commerce in Johannesburg. Spanning 42 electrified railway lines, the bridge (Figure 11.10) has been acclaimed for its functionality and beauty.
Lack of space for the support pylons (towers) between the railway lines dictated that the bridge design would have a long span. This resulted in a structure with the bridge deck supported by stay cables from pylons of unequal height. The pylons on the northern side are 48 meters high, and those on the southern side are 35 meters high.