Sultanate of Oman
Project: Sohar Aluminum Smelter
Location: Sohar, Oman
Client: Bechtel & Co.
Period: Dec 2005
Aluminium is the World’s most abundant metallic element, commercially available in the form of bauxite. With the world market in metals booming, the aluminium industry requires more output to meet the demand. It is hoped that the construction of a new aluminium smelter in the Sultanate of Oman will meet much of the industry needs.
Oman is located at the Northern end of the Arabian Sea and the new smelter is sited just inland from the Gulf of Oman, halfway between Muscat and Dubai. Unlike many other countries in the region, Oman is not a major oil producer. To boost the economy, the country’s government is encouraging foreign investment in light and heavy engineering such as aluminium smelting.
Project:
An aluminium smelter comprises of three main sectors: Carbon, Potlines and Casthouse. It is in the potlines that the aluminium is actually produced. The new Sohar Aluminium Smelter under construction in Oman will feature the World’s largest potline. The $1.4 billion project will contain 360 pots and will be able to produce 350,000 tonnes of aluminium annually. In addition to the potline, the project under construction by Bechtel, includes a carbon plant, a metal casting facility, a port and facilities for shipping and storage. It is planned that the first hot metal will be flowing from the plant by mid 2008.
The pile testing programme originally envisaged by the piling contractor STFA, consisted of top-down static load testing. However, constraints such as availability of reaction beams in a country outside their normal field of operations lead STFA to consider bi-directional testing as a more cost effective solution for this project.
Bi-directional load test arrangement:
Six preliminary bored piles were required to be tested at this site, three 600 mm diameter piles and three 1000mm diameter bored into weak sandstone rock at depths of up to 35 metres. Placing O-cell® arrangements in the smaller pile size proved a challenge, with a configuration of two 230 mm O-cells being chosen to provide the maximum test load requested of 7.5 MN. A tremie pipe size of only 150 mm was sufficient to allow the tube to pass the O-cell assembly and for the placement of the concrete at the toe of the pile. Two number 405 mm O-cells were used in the 1000 mm test piles to provide the required maximum test loads of up to 20 MN.
Summary:
The testing of six piles on our first visit to the Sultanate of Oman, three of which were of a small diameter for bored piles, was a challenge that Loadtest successfully overcame. Proving that size, loads and numbers of tests are no obstacles for Loadtest and bi-directional testing.