Trenchless Bulk Sewer Rehabilitation Projects
AfriCoast Consulting Engineers was heavily involved in the trenchless rehabilitation of three large diameter bulk sewers in Port Elizabeth. The planning, design & tender and construction monitoring phases of these projects were dealt with either as sole consultant, or in joint ventures with other consulting engineering firms.
With the Rehabilitation of Govan Mbeki Avenue Bulk Sewer Phase 1, AfriCoast was the sole consultant on the project, implementing innovative rehabilitation methods never before used in Africa. A badly corroded 450mm diameter concrete sewer main was rehabilitated through the installation of a spirally wound PVC lining utilising “Ribloc Expanda” technology. Similarly, an adjacent 900mm diameter concrete sewer was rehabilitated with the installation of a spirally wound HDPE liner using “Ribline” technology.
In a joint venture with Engineering Advice and Services, the Rehabilitation of Govan Mbeki Avenue Bulk Sewer Phase 2 saw the new “Rotaloc” technology used for the trenchless rehabilitation of a 1050mm diameter concrete sewer, plus a further section of “Ribloc Expanda” rehabilitation on a 525mm diameter sewer. Sections of pipe around bends were lined using Cured in Place Pipe (CIPP) technology. A collapsed 225mm diameter connection into the 525mm diameter sewer was repaired by means of pipe bursting. This project won an award at the International Society for Trenchless Technologies (ISTT) “No Dig” Conference for the use of various trenchless technologies on one construction project.
In a joint venture, with Makhetha Development Consultants, Cured in Place Pipe (CIPP) technology was successfully implemented for the trenchless rehabilitation of a 900mm diameter concrete sewer in the Rehabilitation of Kwazekhele Main Sewer Phase 2 project. In this process, a resin impregnated sock is inserted into the sewer and then blown up with water or air to form a close fit lining securely attached to the inside of the pipe after the resin has cured.