The 60-metre-long Moreland Millennium Bridge, the focal point of the Umhlanga Ridge New Town Centre, is an icon for future strategic developments for the entire KwaZulu region North of Durban.

It is the extraordinary use of concrete form "and the dynamic use of stainless steel which makes this bridge impressive in its asymmetric setting," says Erky Wood, director of GAPP Architects and Urban Designers. GAPP worked with the clie-nt, Moreland Developments, and BCP Engineers to create the concept of the arch, which was agreed to be the most innovative gateway to the New Town. "At night, with mast" mounted up-lighting shining onto large reflectors, the bridge forms a glowing arch of light."

The erection of the arch bridging the main access to the development is constructed using 45 tons of grade 3CR12 and 240 metres of grade 304 stainless steel tube, with a thickness of 3,5 mm and a diameter of 150 mm. All stainless steel was manufactured, at Columbus Stainless in Middelburg. The masts are manufactured from 3CR12 and three stainless steel tubes, each approximately 60 metres in length, form the arches on either side.

"Resistance to corrosion is vital to such a structure, which is permanently exposed to harsh coastal conditions - stainless steel is the perfect material to combat this," says Brian Downie of BCP Consulting Engineers, who is the director of the project. "Coated 3CR12 is a highly cost-effective corrosion-resistant system for a coastal at-mospheric environment, particularly as the corrosion-resis-tant 3CR12 substrate prolongs the coating life."

Corrosion protection
Michael Brett, of Corrosion Advisory Technical Services in Durban (CATS), designed the complementary corrosion-pro-tection system for the structure - all stainless is coated with epoxy coatings and a final re-coatable polyurethane system. CATS Durban performed the coating quality assur-ance and third party inspection, utilising the expertise of Natal Inspection Services (NIS) in terms of non-destructive testing procedures. This was to ensure the integrity of the welding and accurate geometrical laser cutting.

Fabrication of the stainless was undertaken by Impact Engineering. "Careful plasma cutting and submerged arc weld-ing of all stainless steel was the only way to successfully fabricate the work without distortion," says Gordon McNeill, general manager of Impact Engineering. The concrete work, awarded to Grinaker-LTA comprises several unusual features. The abutments - structures supporting the sides of the bridge - are concealed with sloping skirts, which are clad with re-constituted granite slabs. The pier is a perfect ellipse and the underside of the deck curves in a large 30-metre radius forming very thin concrete edges.

The lighting design of the bridge was undertaken by Bosch Projects and, in focusing up-lighters onto the reflector arches, particular care was taken to avoid spill-over light pollution into the atmosphere. Specific accent lighting of various ele-ments of the bridge has also been included in innovative ways. ThyBridge joins the Umhlanga Ridge New Town Cen-tre to the La Lucia Ridge Office Estate and was completed at the end of March. The Bridge, however, will be opened at the time of the much talked-about 125 000m2 Old Mutual Gateway Shoppertainment centre in September this year. The entire development area, about 140 hectares, which is equivalent in size to Sandton's CBD, is owned by Moreland Developments, part of the Tongaat Group. The developers are market leaders in creating value-added, environmentally friendly infrastructure. "The Moreland Millennium Bridge has been such an enjoyable project to work on because of the extremely professional team who were involved and the su-perior quality of the products and materials we worked with," concludes Brian Downie of BCP Engineers.

Brian Downie, BCP Engineers, Tel. (031) 209-4246;
Mike Deighton, Moreland Developments, Tel. 031)560-1900;
Gordon McNeill, Impact Engineer-ing cc. Tel. (032) 947-1054;
Mike Brett, Corrosion Advisory Technical Services Durban (CATS), Tel. (031) 201-0878;
Erky Wood, GAPP Ar-chitects and Urban Designers, Tel. (011) 482-1648.