Clifton Suspension Bridge - still an icon of ambition after 150 years

Brunel's Bristol masterpiece continues to reinforce the economic and social value of infrastructure to society, says Clifton Suspension Bridge Trustee Prof Colin Taylor.

Colin Taylor
08 December 2014

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As the Clifton Suspension Bridge reaches its 150th anniversary on 8 December 2014, Barlow and Hawkshaw's rendition of Isambard Kingdom Brunel's majestic concept for spanning Bristol's Avon Gorge continues to inspire and inform current and aspiring engineers. As an internationally recognised icon of engineering ambition and achievement, its brand value to the the City of Bristol now dwarfs its functional value.

Given the challenges presented by over £400bn of UK infrastructure renewal, the past and future narratives of the Clifton Suspension Bridge hold many important lessons about how infrastructure investment and management both influence, and are influenced by, substantial societal, environmental and technological change.

"Rather than the handful of horse drawn carriages and carts that Brunel would have envisaged, over 7,000 light vehicles now cross every day. This is testimony to the long term value potential that was embedded into the conservative Victorian design."

The bridge is being used by the £3.6m International Centre for Infrastructure Futures (www.icif.ac.uk) as a key case study to rethink the purpose, value, governance and business models of infrastructure provision.

ICIF is taking a service-centric, rather than asset-centric, approach to explore critical issues such as interdependency, resilience and sustainability, which are succinctly exemplified by the bridge. A new, holistic, theory of resilience is being developed, covering ecological, social and technological systems. The theory is intended to reveal better long term infrastructure value propositions.  

The bridge is owned, maintained and operated by a charitable trust, the Clifton Suspension Bridge Trust, established by Act of Parliament in 1952 to preserve and operate the bridge ‘in perpetuity’. The Trust receives no public subsidy to maintain and operate the bridge. All its income is accrued from toll income and the return on the Trust’s accumulated investments.

Every penny of a user’s toll is invested in supporting the £1.5m annual running costs, which include around £1m annual investment in maintenance and upgrades. This investment means that, unlike many of its contemporaries, the 214m span bridge still provides its original service, namely a safe vehicle and pedestrian crossing over the 78m deep gorge.  The income generated by this functional service now effectively maintains the bridge’s more valuable iconic status.

Rather than the handful of horse drawn carriages and carts that Brunel would have envisaged, over 7,000 light vehicles now cross every day. This is testimony to the long term value potential that was embedded into the conservative Victorian design. In the new ICIF theory, this value potential is viewed as being realised every time the bridge is crossed.

Analogous to recharging a battery, the Trust’s expenditure on maintenance is seen as recharging the bridge’s value potential so that it will be available for future users to realise in perpetuity, echoing the core principle of sustainability. This value recharging asset management model arises from the very clear, long-termist, not-for-profit, governance and business model authorised by the Act.

The Clifton Suspension Bridge shows every prospect of reaching its 200th anniversary, and in doing so remaining as a driver of infrastructure thinking and innovation.  

Professor Colin Taylor CEng FICE is Professor of Earthquake Engineering in the Department of Civil Engineering at Bristol University. He is the Bristol Principal Investigator of the ICIF project and a Trustee of the Clifton Suspension Bridge.