Quality and longevity. That’s what you can expect from concrete retaining walls. To withstand Australian weather conditions, a retaining wall needs to be built of high-quality material to suit different types of landscapes. Bawaka landscapes specialise in Brisbane retaining wall design and build.
Termites and other rodents won’t get into concrete like they do in other material. Even when timber starts to rot or bend from harsh conditions, concrete will stay true and be there for a lifetime to come.
Don’t assume that concrete is not flexible in it’s design. If you want to match your existing design colour scheme or landscape, then concrete can blend and match to give you some wow factor.
Skilled labour not required. Concrete sleepers are easily erected, but they are heavy. It’s easily handed by two people and there are no significant foundations required to get started.
They Look Great
Concrete is typically gray, but they can be painted in a wide range of colours. Sealants are important to ensure our sleeper walls look good for years to come.
Manual Retaining Wall Calculation
Measure your area of the wall to determine quantity of blocks required. This area is simply calculated by Length (m) x Height (m) = Area (m2) for basic square or rectangular spaces.
(where m = metres)
Step 1: Measure the area of your retaining wall.
To do this you will need:
– The length of the wall.
– The height at both ends of the wall.
This area is simply calculated by length x height for basic square or rectangle spaces. For odd shapes break your area down into several sections. For triangular areas use half base x height to calculate your area.
Step 2: Increase your total area by 10% to allow for cuts, part blocks & breakages.
Allow minimum 48 hours for concrete to set in post holes prior to installing sleepers.
- Ensure horizontal alignment and correct height spacing prior to inserting sleepers into posts. Use packing under bottom row of sleepers if required.
- Place geotextile to rear face of sleepers to prevent drainage material from flowing through the small gaps between the sleepers.
- Lay slotted rigid PVC pipe behind the sleepers connected to stormwater as detailed in Typical Wall Configuration diagram
The sizes and dimensions shown for the tables in Section 3 and 4 of this document have been based on a Type 3 structure classification to AS4678- 2002.
This assumes that failure of this type of structure would only result in minimal damage and loss of access. For higher structure classifications, engineering advice should be obtained.
The tables shown in Section 3 and 4 of this document assumes that the backfill behind the retaining wall is placed in a manner which is consistent with Controlled Fill – Class 1 as per AS 4678-2002.
The levels of compaction required to achieve this would be 98% of standard dry density in maximum 200mm compacted layers at optimum moisture content +/- 2%.
For retaining walls where it is intended to place and compact the backfill consistent with a lower classification, engineering advice should be obtained.
Post and sleeper size
All steel posts shall be 100UC14.8 or 150UC23 Grade 300 unless noted otherwise (refer Table 3 and 4). The post holes into which these members are placed shall be of a minimum diameter of 400mm or 450mm with minimum 100mm concrete cover at base of hole (refer Table 3 and 4).
Minimum concrete grade in post hole to be 25MPa at 28 days. The sleepers used within these retaining walls consist of precast concrete 75mm thick and 200mm high. Minimum concrete strengths shall be 40
Minimum concrete grade in post hole to be 25MPa at 28 days. The sleepers used within these retaining walls consist of precast concrete 75mm thick and 200mm high.
Minimum concrete strengths shall be 40 MPa at 28 days. Each sleeper shall be reinforced with 2N12 reinforcing bars longitudinal, with minimum 30mm cover.