In the RIBA’s recent report, Joining the dots: a new approach to tackling the UK’s infrastructure challenges, the Institute found that transport infrastructure exacerbates the housing crisis. One of the areas the report focuses on is the need for quality design.
Good design is not just about the striking architecture we associate with big, iconic structures, such as the Millennium Bridge or Birmingham New Street Station. It is also about the functionality of places, the durability of built forms, flexibility of function, and value for money.
Bridges are often considered to belong to the realm of the engineer rather than that of the architect. But the architecture of infrastructure has a powerful impact on the environment and the Millau Viaduct, designed in close collaboration with structural engineers, illustrates how the architect can play an integral role in the design of bridges.
Located in southern France, the 2.46km long bridge carries the A75 autoroute from Clermont-Ferrand to Béziers across the Massif Central. The A75 now provides a direct, high-speed route from Paris to the Mediterranean coast and on to Barcelona. The bridge crosses the River Tarn, which runs through a spectacular gorge between two high plateaux.
- A cable-stayed, masted structure, the bridge is delicate, transparent, and has the optimum span between columns.
- Its construction broke several records: it has the highest pylons in the world, the highest road bridge deck in Europe, and it superseded the Eiffel Tower as the tallest structure in France.
- Each of its sections spans 342 metres and its piers range in height from 75 metres to 245 metres, with the masts rising a further 87 metres above the road deck.
- To accommodate the expansion and contraction of the concrete deck, each column splits into two thinner, more flexible columns below the roadway, forming an A-frame above deck level.
- The tapered form of the columns both expresses their structural loads and minimises their profile in elevation. Not only does this give the bridge a dramatic silhouette, but crucially, it also makes the minimum intervention in the landscape.
Recommendation
Include compulsory requirements for design quality in technical documents, such as a Design Manual for Roads and Bridges
In the UK, design quality is not currently systematically embedded into processes for the planning and delivery of infrastructure. There are a range of procedures and standards that need to be followed for new infrastructure projects, which must be signed off by the relevant local planning and technical authorities. In contrast, design quality issues are much more discretionary.
