The unwritten brief

I have been a bridge designer for many years, and in my experience it's rare for the initial design brief to capture the full possibility of the project. The opportunities we find through interrogating the unwritten brief can uncover missing value. Sometimes the client already has considerable ambition but we see that we can deliver this with additional connectivity, integrating the bridge more fully with nearby routes or transport modes. Alternatively, by proposing a different location or alignment, or by repurposing parts of the existing infrastructure, we are able to design a bridge with less embodied carbon, or which might not be as expensive, risky or complex as our client originally imagined. 

In truth, while the technical engineering and construction work required to deliver a bridge is apparent to everyone, the holistic, humanistic attention that architects provide is not always considered necessary. But if a client is to deliver something with meaningful impact our role is essential. This isn’t just the case for high profile bridges; it’s also the case for more modest projects, where we can add unforeseen value to create something which enriches the community it serves.

Innovative thinking in New Zealand

One project that demonstrates this particularly clearly is currently under construction over the Wēiti River in New Zealand. It is part of O Mahurangi – Penlink, a project in North Auckland that will improve connections to the Whangaparāoa Peninsula. The 540-metre-long bridge – carrying vehicles, pedestrians and cyclists – was procured through a highly competitive design and build tender, with a contractor-led team and significant cost constraints.

Because the meandering river is very wide at this point, an initial reference design showed  a long and visually prominent structure. Reading beyond this brief, we understood that by adjusting its alignment and using an extradosed concrete structure – unique in New Zealand – the bridge could be built:

• at a more appropriate scale: shorter overall, but with a longer span over the river;
• using less embodied carbon; and, crucially
• at no extra cost.

This approach enabled the bridge piers to be moved towards the edges of the river, allowing the crossing to sit respectfully within a very sensitive landscape and, perhaps more importantly, began a process of positive engagement with the local Maori communities who had valid concerns about the environmental and cultural impact of the bridge. The redesigned form, with a clean geometry and a reduced visual mass, seems to emerge from – and relates closely to – the landscape, and provides incredible views to the river mouth. 

Speaking the language of bridge design

Our contractor client recognised the significant value the new proposal would bring – particularly given the sensitive location – and was willing to take the risk of departing from the reference scheme, which had already been approved.

Part of our ability to bring fresh thinking to the project was down to the fact that we are a diverse and multidisciplinary team. We speak the language of the many different parties involved and are able to support their differing motivations and needs. Our multinational team starts each new collaboration with open minds and a willingness to understand how others see the world.

Extending the ambition of projects large and small

Our experience working on the O Mahurangi – Penlink project shows that whatever the location or size of the bridge, its placemaking ambition or its technical constraints, using a specialist bridge architect can add significant value by unlocking the possibility unwritten in the brief.