6.4 Facings

6.4.1 General

6.4.1.1 Facings can be produced in a variety of materials and configurations with a variety of facing-reinforcement connections and a variety of joint fillers and bearing devices.

6.4.1.2 All facings systems and facing units, including connections between facings and reinforcement and jointing materials, when these are needed, shall conform with the specification for the works and exhibit the long term properties required by the design.

6.4.1.3 The facing system shall enable construction within specified tolerances of vertical and horizontal alignment and should perform within specified tolerances of vertical and horizontal alignment over the design life.

6.4.1.4 The facing system should be able to sustain differential settlements required by the design without structural damage to the facing.

6.4.1.5 When vegetation is to be used the face shall provide a suitable medium for the establishment and continued growth of the vegetation.

6.4.1.6 For a vegetated face several interrelated aspects need to be considered, including, the climate, site location, aspect, altitude, amount and frequency of precipitation, exposure, form of facing, erosion resistance capability.

6.4.1.7 Any open joint between the facing units shall be either filled, overlaid with a continuous filler or cover joint, or protected in some other way so as to prevent any leakage of the fine particles of the fill material at the back of the facing. The jointing material shall be pervious unless otherwise required by the specification for the works.

6.4.1.8 Guidance.

Examples of facing systems are described in Annex C.

6.4.2 Prefabricated concrete units (Concrete panel, segmental block wall)

6.4.2.1 Care shall be taken with the selection of the materials used in the production of the facing units and the precision with which they are manufactured, since they affect the performance of those facing units, in terms of achievable construction tolerances and durability

6.4.2.2 All units shall be free of cracks or defects that would interfere with the proper placing of the unit or significantly impair the strength or permanence of the structure. Concrete panels shall conform to EN 1992 or EN 1990, Section 5, if based on tests.

6.4.2.3 Compressibility of filler or bearing pads should be consistent with the compressibility of the retained fill.

6.4.2.4 Guidance.

Specifications for typical examples of widely used concrete units are considered in Annex F, for guidance.

6.4.3 Steel facing units (Welded steel mesh facing, Woven steel mesh facing and gabions, Semi -elliptical steel facing)

6.4.3.1 Guidance.

Specifications for typical examples of widely used steel facing units are considered in Annex E, for guidance.

6.4.4 Geosynthetics facing units

6.4.4.1 All geosynthetics used for the construction of wrapped or bagged facing units or gabion baskets, shall conform with EN 13251.

6.4.5 Properties of facing systems

Facing systems shall conform to the standards specified in Table 1.