Tank construction

Construction of a new US$ 1 billion gas terminal at Freeport in Texas, US is currently underway to meet the high demand for natural gas in the US.

The project, which is being built by a joint venture of Technip USA, Zachry Construction Corporation and Saipem, is probably the largest construction schemes in progress in Texas at the moment and will take three years to complete.

Central to the project are two 122 ft (37.8 m) tall liquefied natural gas (LNG) storage tanks and construction of these structures is being undertaken by Saipem.

The two 270 ft (82.3 m) diameter tanks, which are being built in tandem, feature a double skin wall. The outer is constructed from concrete and carbon steel, while the inner wall is formed by 9% nickel steel, and the space between is filled with perlite to insulate the tank against atmospheric temperature changes.

The tanks' complex concrete structures are being formed using more than 5000 m² of Doka's Top50 formwork and over 2500 m² of platforms from Doka's MF 240 climbing system. The formwork system was selected for the project because it could be pre-assembled to save time on site.

The tank walls were built using self compacting concrete and raised in 4.4 m lifts, which took around 10 hours each to complete. A fleet of 18 concrete trucks were used to ensure that the four 62 m truck-mounted concrete pump were continuously supplied throughout the pour. After completion of each pour, the Top 50 formwork and MF240 platforms were raised into position for the construction for the next section by three cranes.

Construction of the first tank is progressing well - the roof for the tank was lifted off the floor inside the tank in August in preparation for final installation. Construction of the second tank has now progressed onto the final concrete pour and the whole facility is expected to be fully operational by 2008.