Alumina silo - Sohar - Oman
Post-Tensioning and Lifting of Silo Roofs

Scope of works performed

Post tensioning of silo walls and lifting of 2 silo roofs, weighing 240 t each, diameter 42 m and lifting height 49 m.


32 lifting units type SLU 10/200
16 lifting units SLU 30/250


Sohar Aluminium Company

Main Contractor

Carillion Alawi Ltd.

VSL Entity

VSL ME for Post-Tensioning
VSL (Switzerland Ltd.)
Heavy Lifting Department



Project Description

The new and growing port of Sohar, in the Sultanate fo Oman, is turning out to be an important industrial area in the Middle East Region.

By supplying a package service, VSL took an important part in the realisation of two main silos intended for the storage of alumina (alumina is responsible for the metallic alluminium`s resistance of weathering).

VSL Middle East installed 600 t of Post-Tensioning and VSL Heavy Lifting Department lifted the two silo roofs. Each roof, weighing 240 t and with a diameter of 42 m, had been built inside the silo on ground level. As scheduled, only one and a half day was required to reach the top of the silo, 49 m higher, by the use of 48 lifting units working at the same time. The roofs were simultaneously lifted from 16 lifting points corresponding to the 16 radial main girders.

To avoid introduction of horizontal forces into the top of the peripheral concrete wall, they were eliminated by direct transfer to the ground slab by means of an ingenious system, combining cantilever beam and counterweight. Each of the 16 lifting cantilevers supported 3 lifting jacks: 2 x SLU 10 connected to the roof for lifting and 1 x SLU 30 connected to bottom base slab as counterweight to equalise the force.

More information?
Download our job report