Civil Engineering December 2021 | Vol 29 No 11

14 December 2021 Civil Engineering L ocated in the Philani Valley of Umlazi, a sewer trunk line and syphon encased in reinforced con- crete and, acting as a low-level pedestrian crossing, was rendered vulnerable and impassable. Due to illegal sand mining, the riverbed had been lowered to such an extent that the structure was exposed to vandalism, flood action and heavy trucks driving over it. Restoring and protecting the existing sewer line from further damage was not fea- sible. In addition, a pedestrian crossing was desperately required by the communities. The eThekwini Municipality Water and Sanitation Unit appointed Naidu Consulting via a competitive open tender to deliver a much-needed solution for the safe crossing of the Mbokodweni River in conjunction with an upgraded sewer line. Following an in-depth feasibility study a solution was chosen that would provide the following benefits: Q Q Limited environmental impact Q Q Reduced construction cost Q Q Marginal maintenance cost with a 25- year maintenance free guarantee Q Q Maintenance free alternate lighting solution Q Q Faster construction time and lower cost. Naidu Consulting undertook the design and construction supervision of the 160 m long eZimbokodweni Pipe and Pedestrian Bridge. The deck is pre-stressed and comprises six equal spans. Standing approximately 10 m above the existing riverbed, the box girder deck accommodates a 1 000 mm diameter HDPE gravity sewer pipeline. The pioneering adoption of photo- luminescent concrete polymers added a new dimension to safety on the eZimbokodweni Pipe and Pedestrian Bridge. It is the first bridge in South Africa to utilise photo- luminescent “glow in the dark” polymer concrete handrails and posts. The tech- nology was envisaged by Naidu Consulting and developed by Resocrete Polymers. The photo-luminescent concrete handrails and posts illuminate the bridge at night, offering a much-needed solution to the safety of pedestrians. In addition, the foot paths leading to the bridge incor- porate the same material. This technology utilises photo-luminescent polymer con- crete as a lighting solution to eliminate the high costs of conventional electricity as well as vandalism and cable theft. It is SANRAL SA I CE 2021 Nat i onal Awards Category: Techn i cal Excellence WINNER Technical Excellence category (Sponsored by Maccaferri SA) KEY PLAYERS Client: eThekwini Municipality Consultant: Naidu Consulting Contractor: Afrostructures eZimbokodweni Pipe and Pedestrian Bridge The completed eZimbokodweni Pipe and Pedestrian Bridge