Al Khobar Power & Desalination Plant Phase Ii – Civil Works Rehabilitation
The project comprises of the concrete rehabilitation works for the structures of Al Khobar Plant Phase II, mainly seawater intake head, pump house, outlet channels, gantry crane structures, seawalls, siphon basins, chlorine station, in addition to the construction of new seaside roadways. The major repair works in this project consist of two methods, either re-skinning or replacement. The works included but not limited to cofferdams, and/or staging scaffolding, concrete chipping or demolition, installation or replacement of new steel reinforcement, shuttering, concreting, curing application of protective coating, sealant works. In some areas, further specialized works are applicable such as gunniting/shotcreting and crack injection.
The other bulky work is establishing a new seaside roadway along the gantry crane structure. The road is around 400 meters long with works such as backfilling (2m high), shore protection (with armour rock), asphalting and fencing.
The special experiences and challenges involved in this project are as follows:
- Structures subject for repairs are bound by shutdown schedule by the SWCC plant. Works that are completed successfully on schedule are mainly in the Pump House Area, Intake Head Structure Siphon Basins and Collection Basins.
- Another challenge is the rehabilitation works of the Intake Head Structure. This structure is located 1 km away from the shore. We have built 2 Nos. Pantoons fabricated on site. One is 4 x 8 m equipped with engines to transport back and for the miscellaneous tools, equipment, materials, debris, and laborers. The other is 6 x 12m equipped with concrete transit mixer and stationary concrete pump to transport and pour the concrete on the Intake Head Structure. By using these two Pantoons, the need for big barges was eliminated and thus reducing drastically the cost involved in renting foreign barges and tugboat.
- Another special experience is the design, fabrication, and erection of cofferdams to all structures in contact with seawater. A workshop was established for this activity. A team consisting of divers and steel structure fitters was formed and trained to fix these cofferdams.