C.3.4 Review of main systems (p. I)

C.3.4.1 The following tables (Tables C.1 – C.12) assemble brief information about the technology, common applications, performances and tolerances of prevalent systems.

C.3.4.2 The values in the tables are indicative of the construction tolerances which are commonly achieved, or the deformations which are normally withstood without any significant structural damage or any effect on the stability of the structure. They should be understood as follows:

– alignment: local variation in comparison with a 4 m long straightedge placed in the outer plane of the wall face

Key

• 1 Straight edge
• 2 Local variation

– longitudinal differential settlement: ratio ΔS / ΔL

– compressibility: ratio ΔH / H

		REINFORCEMENT	MAIN APPLICATIONS
		Most commonly used with steel or polymeric strips, or steel welded wire mesh. Also with steel ladder strips, rods, or geogrids.	Most commonly used for vertical walls, straight or curved, possibly tiered, and bridge abutments. Slightly battered walls can be built, provided the wall is more or less straight.
TECHNOLOGY	LONGITUDINAL FLEXIBILITY	TRANSVERSAL FLEXIBILITY	FILL MATERIAL
Usually built in vertical rows and a staggered arrangement, which makes propping unnecessary. Compressible bearing devices are applied to all horizontal joints.	Panel aspect ratio, combined with compressible bearing devices gives good system articulation. Hence, significant tolerance to longitudinal differential settlement, especially when panel aspect ratio is near unity.	The compressible bearing devices 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 ± 25 mm	Differential settlement ~ 1% with panel aspect ratio ≈ 1 to ~ 0,5% with larger ratios.	Compressibility ~ 1%

		REINFORCEMENT	MAIN APPLICATIONS
		Mostly used with geogrids, steel strips, or welded wire mesh. Polymeric strips, steel ladder strips or rods can also be used.	Most commonly used for vertical walls a few metres high, straight or curved, and minor bridge abutments. Slightly battered walls can be built, provided the wall is straight.
TECHNOLOGY	LONGITUDINAL FLEXIBILITY	TRANSVERSAL FLEXIBILITY	FILL MATERIAL
Propping is needed during construction.	High vertical panel aspect ratio gives low tolerance to longitudinal differential settlement.	Rigid facing system (unless allowance is made for potential differential movement between the reinforced fill mass and the facing, by means of moving or sliding connections).	Well compacted granular fill material (unless moving connections are used and the system becomes semi flexible).
TOLERANCES			OTHER COMMENTS
Alignment ± 25 mm	Differential settlement ≤ 0,5%	Compressibility ~ 0 % (unless moving connections are used)	Panels with horizontal "fracture lines" having a controlled degree of fragility, are meant to provide some transversal flexibility which eases the mobilisation of the soil/reinforcement interaction.

		REINFORCEMENT	MAIN APPLICATIONS
		Commonly used with steel strips	Sloping straight walls for bulk slot storage facilities. Inclination usually between 50° and 65°.
TECHNOLOGY	LONGITUDINAL FLEXIBILITY	TRANSVERSAL FLEXIBILITY	FILL MATERIAL
Habitually built in horizontal courses in a brickwork arrangement. Buttresses sitting on compacted fill. Compressible bearing pads applied to horizontal joints.	Tolerance to longitudinal differential settlement is limited as a result of the brickwork pattern and since it also affects the evenness of the face.	The compressible bearing pads combined with the direct support by the compacted fill make the systems semi- flexible	Good quality granular fill is recommended especially for high walls supporting superstructure (roof).
TOLERANCES			OTHER COMMENTS
Alignment ± 25 mm	Differential settlement ~ 0,5%	Compressibility ~ 1 %	Placement and compaction of fill between buttresses and under sloping slabs requires special care.