Ecolibrium workplace6

EcoLibrium Workplace6 is the new benchmark in environmentally sustainable building design and touted as the workplace of the future - and Holcim Australia supplied the concrete that contributed to its Green Star rating.

It might sound like something from StarTrek, but EcoLibrium Workplace6 is Sydney's first six Green Star Building.

Known as simply Workplace6, the six-storey, 18,000m3 commercial office building located at Pyrmont, was completed in October 2008.

The building has been modelled as one of the most energy-efficient in the world with an Australian Building Greenhouse Rating of six stars. The project was awarded 83 points - 75 points are required to achieve a six-star rating.

"Workplace6 was the first post-tensioned commercial structure built in Australia utilising a concrete mix design with 40 per cent supplementary cementitious level (comprising a combination of fly ash and ground granulated blast furnace slag) plus a 20 per cent replacement of natural aggregates with slag aggregate," says Stephen Mar, Technical Manager for Sydney concrete.

The new concrete mix design criteria were innovative, as such high levels of supplementary cementitious material (SCM) hadn't previously been used on a project with cyclic post-tensioned flatwork.

"More critically it was something that the majority of the engineering design fraternity didn't generally believe could be readily achieved," says Stephen. "Working closely with our customer, Buildcorp, was absolutely crucial to getting right the specifics of the concrete mix designs for the project and managing the performance expectation of the customer and the other sub-contractors."

At the beginning of the Workplace6 project, the Sydney technical team held numerous meetings with the Buildcorp project management team, TLB (project design engineers) and other subcontractors to explain and review the potential impact on the construction process of a "green" concrete, using a supplementary cementitious material (SCM) level of 40 per cent plus an additional requirement for a 20 per cent recycled aggregate replacement of natural aggregate.

"The successful completion of the project demonstrates that it's possible for a concrete mix design utilising high SCM content to meet the strength development design requirements of a traditional concrete mix design, even despite stringent additional post tensioned concrete design parameters," says Stephen. " Workplace6 is definitely a pioneer project in Australia for concrete construction. It uses a new and innovative concrete mix design philosophy."

The commitment of the Buildcorp project team to build Sydney's first 6 GBCA star project was the overriding project consideration and eventually, reservations about the various effects of the proposed GBCA design innovations compared to more traditional, tried and tested construction techniques, were overcome by the collective resolve of all parties concerned with the construction of Workplace6.

More of Workplace6's environmental credentials:

• Sixty per cent of the steel in the structure is 50 per cent recycled
• Use of PVC reduced by 60 per cent
• Only recycled Forest Stewardship Council-rated timber used
• A central staircase enhances daylight and reduces energy for lighting (it also encourages tenants to walk rather than use the lifts)
• Only low-VOC paints, carpets, adhesives and sealants used
• Mould-prevention system in the ductwork to provide a healthy work environment for tenants
• Alternative energy sources, including its own gas-fired tri-generation system to generate 25 per cent of its base-load electricity, and a solar hot water system
• Cooled using energy-efficient chilled beams that provide a more consistent, comfortable temperature within the building. Instead of cooling towers the mechanical system uses harbour heat rejection
• Another first for Australia; irrigation water to be supplied to neighbouring parks.
• The system has the capacity to produce 40 000 litres of fresh water every day. If the building is not producing enough wastewater, the system will draw on the public sewer and convert this waste into usable water.