Water, Sewage & Effluent September October 2018 | Page 18

appointed a specialist asbestos subcontractor, Drizit Environmental. Kleynhans elaborates: “We only had two areas that were tied into an existing 800mm asbestos cement pipeline, at the Eerste River crossing and at the Macassar pump station, and only had small sections of asbestos that required removal. At the start was about a 10-metre section and at the end, about a 50-metre section. The new outfall sewer followed a different alignment to the existing outfall sewer, effectively on the northern side of the existing sewer.” Project info Client City of Cape Town, Water and Sanitation Engineer Aurecon South Africa (Cape Town) Main contractor Afriline Civils Main Rocla, Infraset, suppliers, Concrete Cape Town Units, Akwasol, and Lafarge ready-mix concrete. Project management “The depth of the excavations required that they be battered, and staff had to work within a ‘drag box’ at invert level to create a safe working environment for our staff.” John Reed, contracts manager for Afriline Civils pump station was replaced with a new sewer line, consisting of HDPE-lined concrete pipes with internal diameters of 900mm and 1  200mm, respectively. The pipes were manufactured by Infraset (900mm) and Rocla produced the 1 200mm pipes and supplied within 40 weeks. While removal of asbestos can be a hazardous process, the length of pipe removed was not of a significant length. Nevertheless, the necessary permits and approvals were obtained, and main contractor on the project, Afriline, Client Keith Olsen Engineer Stephan Kleynhans Contractor Johan Marais (contracts director) John Reed (contracts manager) Chester Adams and Dino Cupido (construction managers) Arno Grobbelaar (safety manager) Christopher Reed (general foreman) Angelo Fortuin (senior surveyor) Duran Young (concrete foreman) Pipe specifications “A total of 1 508 pipes were laid, comprising 2 500mm in length,” says Reed, adding that the logistics of transporting the pipes to site was undertaken with Afriline’s own crane truck, a 22m-long Mercedes 3335 Axor truck and trailer. • • • • DN  1200 diameter pipeline construction, along with existing pipelines that need to be connected to the new system. 16 Water Sewage & Effluent September/October 2018 DN 1470mm – concrete jacking pipes – HDPE-lined 270° – CH3583 to CH3669 – for Macassar Road crossing by pipe jacking method — supplied by Concrete Units — jacked by Wepex. DN 1200mm 100D – concrete pipes – HDPE-lined – CH1200 to CH3770 — supplied by Rocla — manufactured and supplied in 35 weeks. DN 900mm 75D and 125D – concrete pipes – HDPE-lined – CH0 to CH1200 — supplied by Infraset. DN 2600 and DN 1800 precast concrete manhole rings for 48 chambers — supplied by Rocla.