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ROCLA and SPC pipes used in pipe-jacking sections of Rand Water Project
October 21,
2015 2640 2640 
CMA Members Rocla and Southern Pipeline Contractors (SPC) are supplying concrete jacking pipes for eight of 19 pipe-jacking sections which form part of the Rand Water Board’s Palmiet Pumping Station to Signal Hill Reservoir project.
The project’s total piping distance is ±50km and the total distance covered by the pipe jacking sections is 1 100 m.
Rocla was contracted to supply 378 m of jacking pipe for two of the sections (1 x 90 m and 1 x 288 m). SPC is supplying 410 m for six of the sections.
Two pipe-jacking contractors, Wepex and Esor, sought product from both producers as a result of their superior jacking pipe offering and availability.
Luke Woodhams, Contracts Manager of Wepex’s pipe-jacking division, said the 18-month project entails excavating hard rock under residential and national roads, some of which requires blasting.
“The jacking pipes supplied by both Rocla and SPC has a nominal diameter of 2500 mm and outside diameter of 3000 mm and a proof load of 250 kN/m. It is the perfect pipe for this project, which involves pumping water for human consumption as well as having to withstand the immense weight of rail and vehicular traffic,” he said.
Steel pipes are being inserted into the jacking pipe for extra support and for their anti-corrosion properties.
The Rocla pipe is cast vertically using self-compacting concrete to the SANS 677 standard. Self-compacting concrete gives a better surface finish, and vertical casting yields a more consistent pipe-wall thickness. Vertical casting also provides improved compaction and bonding with the reinforcement, which makes the production of extremely thin-walled sections easier.
Self-compacting concrete can increase safety on the job by eliminating the need for consolidation. It offers improved pumpability and labour efficiencies, shorter construction times and can be placed at a faster rate. It requires no automated vibration and enables quicker concrete vehicle turn-around times.
“Rocla had the right pipe with good availability. Their product is of an excellent quality. We are very pleased with the service from them,” Woodhams commented.
Civil engineering and construction group Esor is involved in nine crossings in the Phase B section of the project. Anton Naude, Esor’s Director, Pipe-jacking, said: “The jacking pipes need to be able to last the lifespan of the project, which they will easily do due the quality of the pipes. These are huge pipes that have an approximate mass per meter of 5 680 kg/m and a mass of 8 518 kg/pipe.
“One of the challenges facing the contractors on this project is that the old pipes run parallel to the new jacking pipes. It was imperative that the old piping was not damaged during the installation of the new pipes. This and the fact that we are jacking under roads and railway lines meant that in many instances we had to blast with non-explosive gas,” he said.