Retaining Walls

GRAVITY RETAINING WALLS

Gabion wall base width relative to wall height

The base width of a gabion gravity retaining wall is directly related to the height of the wall. As the wall height increases, the base of the wall must become wider to ensure structural stability. We have provided the diagrams below to illustrate a starting point for design analysis to determine the base width relative to the wall height.

A conservative rule-of thumb value of base width = 2/3 wall height.

Note: A professional stability analysis may determine that the gabion gravity retaining wall base width could be less or greater than the 2/3 wall height rule.

GABION GRAVITY WALL SIZES & DIMENSIONS

DURA-WELD and DURA-FLEX gravity retaining walls can be designed and constructed up to approximately 30’, however due to the configuration of gabion gravity retaining walls their best suited for wall heights of 18’ or less. For wall heights of 18’- 36’ see the Stable Slope Section of this web site.

Gabion wall base width relative to wall height base width of a gabion gravity retaining wall is related to the height of wall so as the wall height increases the base becomes wider to ensure structural stability. Below is a suggested diagram to illustrate a starting point for design. A typical conservative value of base width = 2/3 wall height.

*** A stability analysis may determine that the gabion gravity retaining wall base width be less than or greater than 1/2 – 2/3 wall height.

TYPICAL SIZES & DIMENSIONS – GABION ROCK FILLING

• DURA-WELDTM Gabions: 3″ x 3″ square mesh openings – 4″ – 8″ angular shaped rocks
• DURA-FLEXTM Gabions: 3-1/4″ x 4-1/2″  – 8x10cm hex shaped mesh openings. Fill with 4″ – 8″   angular shaped rocks
• DURA-FLEXTM Gabions: 2-1/2″ x 3-1/4″  – 6x8cm hex shaped mesh openings. Fill with 3″ – 6″  angular shaped rocks

Specific gravity required for the rock fill shall be determined by the design and specified by the design engineer. Specific gravity for rock fill material shall be no less than 2.5

Unit weight of gabion rock fill

TYPE OF ROCK

• BASALT- 180 Lbs.
• GRANITE- 160 lbs.
• LIMESTONE- 138 lbs.
• SANDSTONE- 140 lbs.

GENERAL DESIGN CONSIDERATIONS

Foundation Preparation

Gabion gravity retaining walls are typically placed directly on a graded soil foundation. To increase the bearing capacity, minimize differential settlement, and/or allow for additional drainage, a base layer of granular stone fill with consistent gradation ranging from ½” to1-1/2″ may be placed and compacted to local standards 6” – 18” in depth.

Foundation Grade & Wall batter

It may be determined, through a stability analysis, that additional stability of the gabion gravity retaining wall may be required to achieve acceptable factors of safety from sliding. Options prior to enlarging the gabion wall cross section for additional stability is to excavate and bury half of the first course baskets and erect the gabion gravity retaining wall on a 5 – 6 degree batter towards the retained slope. This will require the foundation soils to be graded and compacted to accommodate for the specified wall batter.

EXAMPLES OF GABION RETAINING WALLS

NOTE: All the above examples are for information only and not to be considered design recommendations. The information provided in the above examples including geo-technical data, dimensions and site conditions are assumptions made by manufacturer and should be reviewed and certified by a Professional Engineer. Please check Local, State and Federal requirements.