C.3.4 Review of main systems (p. II)
Table C.4 - PLANTER UNITS
 |
REINFORCEMENT Commonly used with steel strips |
MAIN APPLICATIONS Vertical, battered or inclined vegetated walls. |
|
| TECHNOLOGY | LONGITUDINAL FLEXIBILITY | TRANSVERSAL FLEXIBILITY | FILL MATERIAL |
| Units installed in horizontal courses and vertical rows. Buttresses sitting partially (vertical or battered walls) or totally (inclined walls) on the compacted fill. Compressible bearing pads applied when units sit on top of each other. (vertical or battered). | Independent units arranged in vertical rows, possibly combined with compressible bearing pads, gives good system articulation. Hence, good tolerance to longitudinal differential settlement. |
The compressible bearing pads (where applicable) combined with the direct support by the compacted fill make the systems semi-flexible | Most commonly used with granular fill material. Intermediate fills can also be used for some applications (see Annex A for guidance). |
| TOLERANCES | OTHER COMMENTS | ||
| Alignment ± 50 mm |
Differential settlement ~ 1 % |
Compressibility ~ 1 % if bearing pads are used More when units are fully supported by compacted fill (inclined walls). |
The layout of battered walls should be straight or polygonal. For curved layouts an adjustment is necessary (modification of the length of facing units within the level) |
Table C.5 - SEGMENTAL CONCRETE BLOCKS
 |
REINFORCEMENT | MAIN APPLICATIONS | |
| Mostly used with geogrids, steel ladder strips or steel grid reinforcement. Other types of reinforcement (steel or polymeric strips) can also be considered. |
Most commonly used for vertical, tiered or battered walls and minor bridge abutments. | ||
| TECHNOLOGY | LONGITUDINAL FLEXIBILITY | TRANSVERSAL FLEXIBILITY | FILL MATERIAL |
| Segmental blocks are installed in horizontal courses and brickwork arrangement, usually without compressible packing material on horizontal joints. Fill reinforcement is usually either held between block courses, or attached to connecting devices at their interface. |
The resistance of segmental block systems to longitudinal differential settlement is limited, since it can only result from the small size of the units and their movements relative to each other. | The lack of allowance for differential movement between the facing and the reinforcement makes the system rigid. | Good quality granular fill is recommended to mitigate the consequences of potential differential settlement between facing and reinforcement. |
| TOLERANCES | OTHER COMMENTS | ||
| Alignment ± 50 mm |
Differential settlement ~ 0,5 % |
Compressibility ~ 0 % |
|
Table C.6 - KING POST SYSTEM
 |
REINFORCEMENT | MAIN APPLICATIONS | |
| Mostly used with polymeric geogrids. The reinforcement is usually connected to a bar that slides on the rear flanges of the king posts or clamped between the concrete planks with a lock on the outside face. | Used for vertical walls only | ||
| TECHNOLOGY | LONGITUDINAL FLEXIBILITY | TRANSVERSAL FLEXIBILITY | FILL MATERIAL |
| Horizontal precast concrete planking slid between vertical steel universal column posts. Compressible bearing pads generally applied to horizontal joints. |
Large panel aspect ratio results in low ability to articulate longitudinally and limited tolerance to longitudinal differential settlement. | The system is semi flexible when compressible bearing pads are applied between the concrete planks. | Granular fill or Intermediate fill material. |
| TOLERANCES | OTHER COMMENTS | ||
| Alignment ± 25 mm |
Differential settlement ~0,5 % |
Compressibility ~ 1 % |
The reinforcement may also be attached directly to the steel posts. In this case the system becomes rigid unless sliding connections are used. |
Table C.7 - SEMI ELLIPTICAL STEEL FACE
 |
REINFORCEMENT | MAIN APPLICATIONS | |
| Steel strips, or ladders, bolted to steel facing units. | Vertical walls (for example for industrial applications) and bridge abutments. Applies to straight or polygonal layouts. |
||
| TECHNOLOGY | LONGITUDINAL FLEXIBILITY | TRANSVERSAL FLEXIBILITY | FILL MATERIAL |
| Facing elements of steel sheet | The large deformability of the | High vertical compressibility of | Most commonly used with |
| formed into semi-elliptical or U- | units gives the system a high | the steel units make the | granular fill material. |
| shaped half cylinders. | resistance to longitudinal differential settlements. | system semi flexible to fully flexible. | Intermediate fills can also be used for some applications |
| (see Annex A for guidance). | |||
| TOLERANCES | OTHER COMMENTS | ||
| Alignment ± 50 mm |
Differential settlement ~ 2 % |
Compressibility ~ 10 % |
|
