Sustainable development: Achieving the balance between design and materials

BG&E Director of Materials Dr Daksh Baweja believes the Australian sustainability lobby over emphasises materials for reducing embodied carbon, to the detriment of the greater potential impact of structural design.

Dr Baweja says, “We cannot continue to ignore the engineering in assessing sustainability.”

“While a positive step in the right direction, popular sustainability benchmarks in Australia, such as the Infrastructure Sustainability Council’s (IS Council) IS rating and the Green Building Council’s Green Star rating can be achieved just by reducing materials with high levels of embodied carbon, such as cement.”

However, BG&E research found that embodied emissions of a short column can be reduced by increasing concrete and the associated cement levels. The inclusion of higher strength grade concrete with higher cement content can enable use of less steel reinforcement and a reduction in the volume of materials used, reducing a structure’s overall embodied emissions.

Advanced carbon lifecycle assessment metrics, such as those by The London Energy Transformation Initiative (LETI), apply a more rigorous emphasis on the project lifecycle and the role of the design phase in determining materials used, construction processes, the structure and its performance.

Dr Baweja says, “The sustainability landscape in Australia is where the UK was five years ago.”

BG&E’s London office adopts both efficient design and sustainable materials to reduce embodied carbon by up to 55% for projects, in accordance with LETI’s sustainability metrics.

However, it is promising to see the best practise method for optimal sustainability – the reuse or upcycling of buildings, is making inroads in Australia with the iconic Quay Quarter Tower (QQT) project, which will see Sydney’s 1970’s AMP building redeveloped to deliver a new contemporary neighbourhood with 52 storeys of innovative commercial space, five basement levels, 104 luxury residential apartments, prime retail, green spaces and artisan cafes.

The joint venture by BG&E and ADG Consulting Engineers will be the first national example of a new commercial building built around two-thirds of the retained core of an existing high rise. The reuse of materials resulted in a total carbon saving of over 7,500 tonnes, and an estimated economic saving of $130 million. 1

Dr Baweja says, “There is no better way to reduce embodied carbon while significantly reducing construction costs, than reuse or upcycling.”

In recognition of this fact, the Royal Institute of British Engineers has issued an upcycle policy to be used for projects in the UK wherever possible.

The proposed $320 million regeneration of the Remada Renaissance in Manchester’s city centre constitutes another best practise example of upcycling. BG&E advised Mace Group regarding the 27-storey tower designed to house residential apartments alongside the existing Renaissance hotel, complemented by a new green public space along the River Irwell, pop-up food and drink vendors, new footpath and a cycle lane.

Left to right: Reza Hassani, Kerrod Potter, Xiaoyu Gu, Thomas Flood, Leonard Ambrogi, Sean Windred, Rami Jeaitani and Joe Daven.

BG&E helped to deliver the Bunbury Outer Ring Road (BORR) in Perth in West Australian.

The new tower will be built around the existing core, reducing the need for demolition and generating total embodied carbon savings of around 2,760 – 3,800 tonne CO2e.

With science dictating this is the decade that the future of our planet is determined by the pace of climate change, it is clear that there is an immediate role for the urban built environment industry, which is responsible for 75% of annual global Green House Gas Emissions

Dr Baweja says, “Sustainability is now the thing you have to do in order to fulfill your duties to the industry, the communities we shape and the planet.

“It is essential to look at the bigger picture and cut through popular misconceptions and myths. It’s not about what you put into a structure, but what sustainability benefits you get out of it across the lifecycle.

“Engineers are best placed to provide holistic sustainability advice, with technical expertise regarding the design phase and materials.”

Dr Baweja continues to pursue sustainability innovation in both a professional and academic capacity, as an Industry Fellow at the School of Civil and Environmental Engineering at the University of Technology in Sydney, a widely-published author of technical papers on the durability of fly ash and other concretes, and has held executive roles at CSR, Readymix and Rinker, among others.

BG&E Director of Materials Dr Daksh Baweja

1 Australian Circular Economy Hub: Quay Quarter Tower – The Sydney Office Building Implementing Circular Design on a Mammoth Scale, 2022.

2 UN Environment: 2021 Global Status Report for Buildings and Construction, 2021.