A British engineering professor who has spent the past quarter of a century searching the organic world for solutions to human engineering dilemmas claims to have produced the optimal bridge design.

Professor Emeritus Wanda Lewis from the University of Warwick's School of Engineering is a veteran of rifling through the endless catalogue of organic structures that abound in the natural world to solve human engineering dilemmas.

She has spent 25 years engaged in the pursuit of "form-finding," looking to natural phenomena such as trees, leaves or shells to produce more resilient designs for man-made structures.

Lewis may have now solved the centuries-long riddle of what shape makes for the ideal bridge arch by using form-finding to produce mathematical models for more resilient structural designs.

Form-finding has long promised to produce structural designs that are capable of sustaining themselves solely by means of compression or tension, while remaining free of the bending stresses that comprise their primary source of weakness.

This could lead to the creation of stronger and more durable bridges or buildings that require far less maintenance or repair. Such structures would theoretically be capable of bearing permanent loads in any configuration without suffering from complex stresses.

Organic forms generally possess simpler stress patterns, enabling them to better withstand any heavy forces that beset them, like heavy winds in the case of a tree for example. In Lewis's words, "nature's design principles cannot be matched by conventional engineering design."

Lewis notes that despite their aesthetic appeal, many long-standing classical designs for bridge or building structures are in fact structurally flawed.

"Aesthetics is an important aspect of any design, and we have been programmed to view some shapes, such as circular arches or spherical domes as aesthetic," she said. "We often build them regardless of the fact that they generate complex stresses, and are, therefore, structurally inefficient"

Lewis' work involves using mathematical models to develop structures based on natural designs that possess simpler stress patterns. She believes she has found a new mathematical solution for the optimal arch when subjected to general loading, and published a paper on her research in the Proceedings of the Royal Society A.

If Lewis has indeed produced the optimal bridge design, then the engineering world can look forward to the development of bridge structures that are far more sturdy and enduring than the catenary or inverted parabola designs advocated by pre-modern architects. (expire Jan 30, 2017)