BS EN 14620-3:2006 – Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of refrigerated, liquefied gases with operating temperatures between 0 °C and p165 °C — Part 3: Concrete components

8 Detailing provisions
8.1 General For general information on pre-stressed concrete tanks, reference should be made to Annex B.
8.2 Pre-stressing For the pre-stressed concrete wall, horizontal pre-stressing shall be applied. NOTE Vertical pre-stressing is not required. It can be combined with horizontal pre-stressing. The need for vertical pre-stressing depends on the tank design pressure, tank diameter, and associated permanent and transitional stresses within the concrete section.
8.3 Wall design The minimum wall thickness shall be determined so that: adequate cover to all reinforcement and pre-stressing tendons shall be available; space between the reinforcement and pre-stressing tendons shall be sufficient to ensure that a homogeneous, liquid tight concrete structure is obtained.
8.4 Steel roof liner The steel roof liner shall be anchored adequately to the concrete roof.
NOTE The liner may act as formwork for the concrete and may also act compositely with the use of shear studs. The concrete may be built up in layers to prevent overstress of the liner (see also B.6)
8.5 Construction joints Attention shall be paid to the design and execution of the construction joints. The location and necessity shall be carefully planned to minimize the risk of poor jointing. For the areas where liquid tightness is to be assured, the contractor shall provide method statements based on proven working practices and where necessary, due to lack of evidence, the contractor shall carry out tests to demonstrate that the construction joint is liquid tight.
8.6 Position of tendons and wires For internal pre-stressing systems using buttresses and grouted tendons, due account of the emergency conditions, e.g. fire scenarios, shall be taken to determine the position of the pre-stressing system.
NOTE 1 Tendons should be preferably placed, in the centre of the concrete wall for protection against external fires. The tendons shall be well protected from corrosion during the life of the tank. Grouting procedures shall be provided and agreed between the designer and contractor to provide adequate protection to the tendons.
NOTE 2 In very aggressive environments, where additional protection is required, for the tendons, non-ferrous pre-stressing ducts may be considered. Reference is made to „Durable bonded post-tensioned bridges‟ Concrete Society Report TR47 [1 2]. For non-bonded tendons, reference should be made to FIP recommendation 91 [1 3].
BS EN 14620-3:2006 – Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of refrigerated, liquefied gases with operating temperatures between 0 °C and p165 °C — Part 3: Concrete components