Three ways structural engineers can help create a zero-waste future
Rethinking production and the
life cycle
Despite continuing efforts to reduce
inefficiencies in the construction industry, excessive waste remains a problem:
there is a real need to rethink production of components and systems (which are
inefficient from a resource use and manufacturing technology standpoint) making
better use of advanced manufacturing technologies and prefabrication.
When we think about waste we also have to
consider maintenance and asset management of buildings, which are frequently
inadequate, relying on limited data to monitor the building’s condition. This
means that when a building reaches the end of its life, a critical stage, it’s
hard to practice selective demolition - which could retain parts of a structure
and reduce waste.
Some companies try to reduce waste by using
demolition contracts that allow an effective stream of construction waste -
however, this is typically limited to traditional construction materials, such
as concrete and metals. The issue becomes more complex when you consider
composite materials, and complex building components and systems. There is a
need to develop regulations and procedures to allow the recovery of more
demolition waste.
Disassembly not demolition
Really we should use the term ‘disassembly’
rather than ‘demolition’ - meaning that each material should be chosen and
designed to be easily detached and separated from the others. Even better, a
‘selective disassembly’ would allow components still in good shape to be reused
in other projects and construction works. This is not fiction, but
well-established practice in other industries, such as the automotive industry.
There are limited examples of established recycling in construction: steel,
aluminium and copper are reused in secondary production streams, while concrete
is ground and re-used as filler in future mixes. Still, there is a long way to
go. The advance of technology and digital platforms will be a key enabler of a
transition to selective disassembly.
Urban Bio-Loop: Sharing Waste
There is much to do to expand re-use,
re-manufacturing and re-cycling in the construction sector, but I see an
opportunity to merge different sectors to share waste as a resource. The
example that we present in The Urban bio-loop: Organic waste from our
cities and the coutryside, traditionally managed through landfill and
incineration could become a resource for the creation of construction
engineering and architecture products, before being fed back into the
biological cycle at the end of their service life. Opportunities like this will
become more valued in the future, as stakeholders realise waste is actually a
precious resource.
An important first step is to work with
governments to rethink construction codes and regulations, providing
opportunity to repurpose waste on an industrial-scale.
Then we need to invest to develop bio-based
materials, proving their applicability from a performance standpoint, for
example, in respect to fire performance or durability. Improved understanding
will allow us to exploit the huge untapped potential of organic resources in
construction for specific applications.
Bio-composite materials are a mix of
bio-polymers and natural fibres. Their advantage is that, depending on the case
and polymer composition, they are compostable and biodegradable. These products
are derived from natural resources that grow abundantly in nature, such as
hemp, flex, jute and soy so are potentially infinite, regenerable, and clean.
Circular Building
Arup recently demonstrated that a circular
building approach, using entirely re-usable components, is very possible -
through the circular house project.
A number of factors need to be refined to make circular
buildings more attractive from an investment standpoint, as well as to mitigate
associated risks. Regulations and a governance-level approach will be needed to
make this transition happen in the future, alongside a large education campaign
to make stakeholders aware of the benefits of a circular economy.
3 ways structural engineers can help create a
zero-waste future:
· Design for the End of Life - Engineers should work for a different design approach, that pays more attention to the end of buildings’ lives, and how structural components could be designed to be easily detachable and possibly re-usable.
· Design for future flexibility - Engineers can ask design teams to consider buildings’ future functional implementation, in case of design life extension and repurposing.
· Design for an efficient use of resources - engineers should promote the use of the latest manufacturing technologies to minimize resource consumption, without compromising the performance.