Edition 10

News & project profiles from the team at Concrib

in this issueProject profile: Attractive sleeper wall solution provided for Mango Hill development

Project planning: Three questions you MUST ask before choosing your retaining wall

Engineered retaining walls: Maximising land values

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

attractive sleeper wall solution provided for Mango Hill development

ProjECt ProFilE

Fairmont Group, an Adelaide based property development company, recently began construction of a 107 lot residential subdivision at Mango Hill, located north of Brisbane. Each lot ranges in size from 300sqm to 2000sqm.

The development has been enhanced through careful design and construction, enabling many of the allotments to have serene views of the adjoining bushland and Freshwater Creek.

Project: Crest Estate, Mango Hill 2800m2 of walling with max heights up to 4.6 metres

Client: Fairmont Group

Contract: Design / Construct / Certify Concrib Concrete Sleeper Retaining Walls Continued overleaf...

However, there have been a number of obstacles to overcome. For example, one of the key requirements for this project was to be able to present attractive, “ready to build“ flat blocks to the market. To achieve this, Fairmont Group decided to cut and fill the site, thus requiring retaining walls fit for this purpose.

Concrib provide a turnkey solutionThe development covers approximately 11 hectares and was subject to a high degree of rise and fall across the site. That’s when Concrib were engaged to provide a complete turnkey contract to design, construct and certify the walls.

In total, about 2800sqm of retaining wall was required, with 1900sqm being up to 3m, and 830sqm of very high walls varying from 3m to 4.6m. The great advantage of

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sleeper walls is the relatively narrow area of land required – thus maximising the overall value of the development.

To provide maximum usable space for each property, it was decided the walls should be of vertical cantilever concrete sleeper wall design - incorporating steel columns as the vertical supports. Many of these steel columns weighed up to 656kg!

Careful installation techniques were used throughout this project, including precise clamping and placement of the steel columns. The result? A great looking, and well engineered retaining wall.

ProjECt Planning

three questions you MUst ask before choosing your retaining wall

mmaxiiimiiisiiingg lland valuesmaximising land values

ProjECt Planning

There are many factors involved in choosing the right retaining wall for your project. In Maxim Edition 8 we looked at the four broad categories of retaining walls: gravity walls, cantilevered walls, anchored walls, and reinforced soil or nailed walls.

This time around, we cover three questions you must ask if you want to select the best type of wall for your project.

With decades of experience in the earth–stabilisation business, Concrib has the expertise to provide tailored solutions for a vast range of projects. This list is by no means definitive, but it aims to equip you with sufficient information to guide you through the initial phase of the decision making process.

Will this meet all building codes and legislation?It is important to remember that the retaining wall structure must comply with the AS4678 Retaining Structures Code, and any manufactured/fabricated products must also comply with their respective codes. For example, structural concrete must fulfill the requirements stipulated in AS3600.

What must be done to ensure durability of the wall?The structure must be durable and meet the design life requirements stipulated in the relevant construction codes. Long–term maintenance requirements must be taken into consideration and factored into the cost.

While this checklist serves as a useful guide for choosing the right retaining wall, it is important to remember that every project is unique, and it pays to consult the professionals when finding the right solution for your project.

It’s important to consider the wall height to footprint ratio required for your project. Depending on the application, crib walls can be built to heights over 10 metres, but being a gravity system, the higher the wall, the thicker the base, or footprint, must be. This makes them unsuitable for applications where vertical height is required and space is limited.

Concrete sleeper walls can be used in either cut face or fill applications. As vertical

cantilever systems, they typically have a narrow footprint (usually around 500 millimeters), which makes them ideal for small lot housing developments where the land space can be maximised. Sleeper walls are used up to heights of 3 metres with a vertical face.

The table shows typical wall heights and corresponding footprints for boulder walls, concrete crib walls and concrete sleeper walls.

What size footprint will this project require?

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Wall height/

mmBoulder walls Concrete crib walls Concrete sleeper walls

Base Setback Footprint Base Slope Setback Footprint Base Setback Footprint

1000 800 550 1350 500 250 200 950 280 200 480

1500 1100 650 1750 700 375 200 1275 310 200 310

2000 1400 775 2175 1000 500 200 1700 350 200 550

2500 1750 900 2650 1000 625 200 1825 380 200 580

3000 2150 1025 3175 1000 750 200 1950 400 200 600

Wall height and footprint comparison

mmaxiiimiiisiiingg lland valuesmaximising land values

Concrete sleeper retaining walls

EnginEErEd rEtaining wallsMaximising land values

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

Patterned sleeper retaining walls

gabion and rock mattress structures

rockfall nettingrockcatch fencingnew directions crib panel facing

CoMPany nEws

For Category 1 of the prestigious CCF Earth Awards 2009, 2010, 2011 & 2012 – celebrating “Excellence in Civil Construction.”

2012 Finalists

stone strongConcrete crib walls

segmental walls