Manufacture and installation of precast parts in the outfall pipe project at South Pars - phases 9 and 10

This project is located in Assaluyeh region of Bushehr Province. It was aimed to transport refinery waste water through 56 inch polyethylene pipe 6 km long on the 10 m deep sea floor.
Considering the nature of the project and previous experience in manufacture of precast concrete part, and also availability of well-equipped prefabrication unit of Perlite in the area, production of all concrete parts were considered to be precast. Also, "flex-mat" for the first time precast concrete covers were used over the pipe laid on the sea floor, instead of soil and rock embankment.

Steam curing was used during production cycle of precast parts. This caused the parts to reach 70% of their 28th day of strength through 10 -12 hours of steam curing.

The following include some advantages of stem curing:

  • Need for less formworks and reduction of daily cost
  • Saving time due to reduction in curing time
  • Reducing the area needed for the operations.

The following table gives the total number of precast parts in the project: 

Type of precast part Quantity
Offshore  weights 166
On-shore weights 575
Type 2 offshore weights 85
On-shore manholes 24
Manhole covers 72
Flex-mat concrete covers 292
Offshore concrete bends 1
Total precast concrete parts (cu m) 1400


Flexible Armour Shield


Sinking Weight


Manhole Coverage


Diffuser Anchor Block