 DSI Team Effort Post-Tensions Two LNG Tanks in Freeport, TX, USAFreeport LNG, Freeport, Texas, USADSI USA undertook the supply and installation of the post-tensioning material for two LNG tanks each with a 40.7 million gallon working capacity. The project was developed by Cheniere and is now jointly owned by Cheniere, Smith Entities, Dow Chemical and Osaka Gas. The joint venture Technip Zachry Saipem designed and built the facility. Each tank is 270’-0” in outside diameter, 158'-0" high to top of dome and has a concrete wall thickness of 2'-7.5" incorporating four buttresses. During the construction of the concrete walls, DSI provided technical guidance to the general contractor and oversaw the installation of the duct and all embedded tendon items. After completion of the wall construction, DSI crews pre-fabricated and installed the vertical "U" tendons, then continued on to the installation of the horizontal tendons. Tendons were grouted as installation progressed in 20 – 25 tendon groups. Each tank has (67) pairs of 19x0.6" horizontal tendons anchored in buttresses 180 degrees apart and (110) 19x0.6” vertical tendons meeting the cryogenic requirements specified where required. All tendons were stressed simultaneously at both ends. DSI used personnel from the post-tensioning operating unit within the USA. Post-tensioning installation was carefully coordinated in order to attain continuous work without demobilization, minimum crew size and maximum production. Crew size averaged 6 men for full project duration. The works were completed to the full satisfaction of the Client in December 2007. |