Edition 12

News & project profiles from the team at Concrib

Phone: (07) 3375 1800 Fax (07) 3375 1777Email concrib@ecn.net.au Web www.concrib.com.au

Brookwater Residential SubdivisionPROJECT PROFILE

BROOKWATER STAGE 11D

Concrib Concrete Crib Wall SystemBrookwater is a master-planned community in the burgeoning western growth corridor of Brisbane. The site is being developed by Springfield Land Corporation and offers premium residential blocks surrounding the renowned Greg Norman designed golf course.

The stage 11D release is located to the west of the course and offers thirty large allotments. As the land sloped away steeply across the stage from the east to the west, a decision was made to build a retaining wall along the western boundary with an average height of about five metres. The associated cut / fill operation would thus produce a far greater yield of near level home allotments.

Concrib were engaged by the main civil construction contractor, BMD Urban, to provide a turnkey Design & Construct contract for a Concrib engineered retaining wall. As the toe of the wall sloped away at up to 2h:1V the crib wall design incorporated deeper than usual embedment of the wall base. Minimum bearing capacity of the founding material was 250kPa, with the retained material being a sandy clay, friction angle 32 degrees and a density of 21kN/m3. The design is fully compliant with the Australian Standard for retaining structures AS4678, incorporating a surcharge load of 5kPa and a design life of 60 years.

Approx 1140m2 of terraced walling and 450m2 of single crib walling was completed on the project. See over for more photos...

In this issueProject Profile: Brookwater Residential Subdivision

Due Diligence: A total reliance on compliance

Project Planning: Choosing the right retaining wall for your project – Part 2

Company News: We’re now on YouTube... See our new 3D animations!

AS4100 Steel Structure This standard establishes the minimum requirements for the design, fabrication, erection and modification of steel in structures. Therefore the quality, strength and bar diameter are paramount. Equally important is the way the steel has been treated, for example zinc coating on fabricated ferrous (hot dipped galvanised steel) must comply with AS4680.

“ It’s crucial that no shortcuts be taken…otherwise they may be found out”

Be they concrete, concrete masonry, reinforced concrete or steel, all engineered retaining wall products must comply with Australian Standards.

Concrib’s retaining walls are purposely designed to do so, which is why our customers have come to rely on us.

With that in mind, we would like to detail precisely what is involved with compliance across all mediums, starting with the overall standard for Australian Retaining walls, AS4678.

DUE DILIGENCE

A total reliance on complianceThis standard takes into account a number of important issues such as whether they fit their purpose, durability and design life.

It’s crucial – particularly in the long run – that no shortcuts be taken in their construction, otherwise they may be found out in the event of flood or if the structure succumbs to stress.

If ever it does, it may involve costly remediation, particularly if the problem has affected adjacent buildings and structures.

Now, let’s look at the other links in the chain, all of which need to comply.

Concrib is committed to upholding all of these standards.

AS 3600 Concrete StructuresThis standard sets out minimum requirements for the design and construction of concrete structures that contain reinforcement steel, or tendons, or both. Major points addressed in the standard relate to design methodology, durability, strength, climatic conditions and cover.

AS4680 Galvanised Coatings Important points covered in this standard relate to appropriate coating thickness and mass per unit area of zinc coating and coating adherence. These properties dictate the durability and design life of the galvanised steel article for particular applications.

AS3700 MasonryThis sandard sets out minimum requirements for the design and construction of masonry, including unreinforced, reinforced and pre-stressed, using manufactured units of clay, calcium silicate and concrete laid in mortar, autoclaved aerated concrete (AAC) laid in thin-bed mortar, and square-dressed natural stone laid in mortar.

mmaxiiimiiisiiingg lland valuesmaximising land valuesPROJECT GALLERYBrookwater Residential Subdivision

In Maxim 8, we presented an overview of the four distinct types of retaining walls – gravity walls, cantilever walls, anchored walls, and reinforced soil or nailed walls.

In this issue, we will discuss the difficulties of retaining cut faces on property boundaries, other considerations and the importance of aesthetics.

PROJECT PLANNING

Choosing the right retaining wall for your project

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Generally, building a wall to retain fill material allows for a wider choice of walls than a wall designed to retain cut faces as the reinforcing elements are encapsulated in the fill.

Cut faces limit footprint size and may not be suitable as the reinforcing elements (grids or straps) will encroach over the boundary.

Reinforced walls also have to be bulked out and then either re-compacted or replaced with a suitable fill material. This is often impractical for cut face applications — even when the face is not on a boundary.

Crib walls are one of the best options to retain cut face sites, as are boulders, however these structures require skilled operators and rigorous monitoring during construction.

Other considerations for retaining walls• Wall environment (e.g. soil chemistry,

salinity, etc)

• Accessibility of the area

• Size of the footprint available

• Required height and length

• Slope of the ground above and below the wall

• Surcharge loads applied above the wall (including live loads such as roads, or dead loads such as buildings)

• Availability of solid ground for a foundation

• Any services, trenches or pipelines near the base of the wall

The beauty of modern retaining wallsUnlike older style and timber walls, modern retaining walls can be planted out for a more natural look.

They can have a wood grain finish or come complete with long-lasting coloured sealants to enhance their aesthetic aspect.

PART 2

mmaxiiimiiisiiingg lland valuesmaximising land values

Which type is right

for you?

Stone Strong

Concrete crib walls

Call us today to plan your next project. Phone: (07) 3375 1800 Fax (07) 3375 1777Email concrib@ecn.net.au Web www.concrib.com.au

Concrete sleeper retaining walls

ENGINEERED RETAINING WALLSMaximising land values

Patterned sleeper retaining walls

Gabion and rock mattress structures Rockfall netting

Rockcatch fencing

New directions crib panel facing

Segmental walls

Ever wondered how we construct our retaining walls? Wonder no more!

We now have a series of fascinating 3D animations you can watch.

Go to YouTube and type in Concrib 3D, or follow the link from our website.

COMPANY NEWS

We’re now on