The pumping station (PS70)is part of the Doha North Sewage Treatment &Associated Works program. The PS70 project includes the construction of two 40 m deep shafts “screen chamber” and “lifting pumping station”, with a 20 m diameter and 40 m diameter respectively. Doka formwork has been used to build the walls of both the screen chamber and lift pumping station shafts. For this massive structure and very confined site conditions Doka offered its dam formwork D22, taking into account its high-load capacity and operational safety.
Outer walls of the pump station have been single-sided with 412 m2 of the large-area formwork Top 50 and 74 nos of D22 cantilever brackets thus fulfilling the very high safety requirements posed by the contractors, VINCI Construction. Doka D22 dam formwork was also used for the outer circular walls of the screen chamber. The climbing formwork started from the raft and the walls were done in 11 lifts with a typical casting height of 3.40 metres. At both structures the outer walls were cast 3-4 casting steps ahead of the inner walls to enable fast progress and avoid any interruption during forming operations.
Multi-purpose formwork solution
A combination of the Top 50 wall formwork, MF240 climbing platform, the telescopic shaft platform and the guided-climbing platform Xclimb 60 was used for the inner walls. On account of the limited crane capacities, i.e. only 2 cranes on the construction site, the number of platforms required was optimized so that the platforms can be shifted with a minimum of crane lifts.
In addition, Doka has provided formwork equipment for all the remaining works. The Staxo 40 load-bearing system has supported the floor slab with an area of 323 m². Doka framed formwork Frami combined with the supporting construction frame was used to cast 258 m2 wall area of the mass concrete blocks in the pump station. In the adjacent Motor Control Center2 building the contractors used Dokaflex 20 and Staxo 40 systems for the slabs having an area of 246.00 m2 and Framax Xlife wall & column formwork with for two sided walls of 70.00m2
Exact planning, technical assistance and continuous training and support directly on the construction site made it possible to achieve this enormous output with chronological precision and with no unexpected incidents whatsoever.