Section 1 General

1.1.1 The Chapters in this Part outline the structural design requirements of ship and barge type units, built in reinforced and/or pre-stressed concrete. The design for other types of floating concrete units will be specially considered, although the general principles given in this Part are applicable. The general requirements for structural unit types in Pt 4, Ch 4 Structural Unit Types and Pt 4, Ch 5 Primary Hull Strength are to be complied with as applicable.

1.1.2 This Part only considers the design requirements for the concrete structure of the unit. The requirements of this Part are considered to be supplementary to the requirements in the relevant Parts of the Rules.

1.1.3 These Rules are intended primarily for units engaged in production and/or crude oil storage as defined in Pt 3, Ch 3 Production and Storage Units, to which reference should be made.

1.1.4 Special consideration will be given to units required for the storage of liquefied gas or liquid chemicals in bulk. The following technical aspects are to be considered in full for the storage of liquefied gas:

1. selection of gas containment system;
2. interaction between concrete structure and containment system;
3. the effects of temperature on the concrete, see Pt 9, Ch 4, 2.6 Freezing and thawing;
4. fixing/embedding the containment system supporting structure in concrete;
5. arranging a moisture barrier where considered necessary.

1.2.1 These Rules give requirements for detailed design. Recognised Codes and Standards which give an equivalent level of safety will be considered but must be agreed by Lloyd’s Register (LR) in each case.

1.3.1 The Regulations for classification and the assignment of class notations are given in Pt 1, Ch 2 Classification Regulations, to which reference should be made.

1.3.2 In addition to the normal class notations which may be assigned to an installation, for concrete units a suitable descriptive note will be included on the Class Direct website, e.g. concrete hull.

1.4.1 Plans, calculations, data and specifications are to be submitted in accordance with Pt 4, Ch 1, 4 Information required as per steel structures, as applicable.

1.4.2 For units with process plant or drilling plant, the additional plans and information required by Pt 3, Ch 7 Drilling Plant Facility and Pt 3, Ch 8 Process Plant Facility, as applicable, are also to be submitted.

1.4.3 In addition to the above requirements, plans are to contain reinforcement and pre-stressing details for the whole concrete structure.

1.4.4 Calculations are also to be submitted for the serviceability and progressive collapse limit states in addition to the ultimate strength and fatigue calculations required in Pt 4, Ch 1, 4.3 Calculations and data 4.3.1.