Minimising Future Surprises at Bridge Conceptual and Aesthetic Design

Abstract

The conceptual design of bridges is a critical task with the need to assess feasible schemes, not to hinder creative work, but to avoid appealing aesthetic concepts outside feasibility constraints. Ongoing bridge failures, often during the construction of innovative designs, underscore the need to re-emphasise safety and design fundamentals when pursuing aesthetic designs. The inability to provide timely reasonable cost estimates likewise leads to later embarrassing surprises. Public confidence in the bridge engineering profession suffers. This paper is not about the numerous aids to facilitate aesthetic concept development. It attempts to promote bridge conceptual design that is amenable to control. Well-reported historic failures, focusing on pioneering bridges and novel and elegant designs, are reviewed for retrospective insight and current relevance. The repeated findings of loss of control in the design and/or construction process suggest the benefit of forward risk assessment, value engineering and constructability analysis, at concept, for both structure soundness and cost estimation, especially for major signature structures. The necessity for critical independent review is accentuated. The conceptual and aesthetic design of evolving bridges demand excellent multidisciplinary engineering capability and foresight.

Keywords:

• conceptual design
• pioneering bridges
• aesthetics
• failure case studies
• constructability
• value engineering
• risk management

Acknowledgements

Constructive comments from two anonymous reviewers are gratefully acknowledged. Like most, the author’s professional experience has been influenced by events during early education and opportunities provided throughout his career. The author was fortunate to have had some great mentors, especially Structural Design Professor Tom Paulay, University of Canterbury, New Zealand in the 1960s and acknowledges the impact of many creative-thinking clients and colleagues during years of practice, and the inspired focus of IABSE Bath 2017.