Under Peck's method, which has pushed the boundaries of ground engineering, tunnels and dams are designed optimistically by closely monitoring soil behaviour during construction. This enables the structure to be designed to the limit of what is possible.
The OM requires robust fall back positions that can be implemented if at any time safety is in danger of being compromised. The technique reflected Peck's belief in sound engineering judgment and testing as opposed to the emerging science of numerical analysis and modelling.
Peck first used the technique when working with "the founder of modern soil mechanics" Karl Terzaghi on the Chicago subway project 1939-42. He eventually formalised his ideas in his seminal Rankine Lecture at the Institution of Civil Engineers in 1969.
He described it as "allowing nature to speak for herself".
"Nothing is better practice than predicting and verifying how the subsurface materials will behave, and adjusting the design and construction procedures on the basis of the observations as a project proceeds."
Peck's method was championed by his profession, but many project clients and insurers remained suspicious of the OM because of its uncertainty and were reluctant to sanction it despite its obvious success on major projects, including the Channel Tunnel.
In the UK, it was most commonly used as a "best way out" to rescue projects that had spiralled out of control, months behind schedule and millions of pounds over budget. Despairing clients would finally succumb to project engineers who had been calling for the OM to be used from day one.
But Peck spoke out against a "misuse" of his method through "overreliance" on modern theory and computer analysis that did not take proper account of ground conditions. "Theory and calculations are not a substitute for judgment, but only the basis for sounder judgement," he said.
Peck spoke from long experience of consulting on more than 1000 projects during a long career. Most of these were trouble shot in the lecture hall during a long academic career as professor of foundation engineering at the University of Illinois from 1948-74.
Peck was famous for making his students turn off their calculators and pack up their slide rulers, and instead think more laterally about how to solve complex engineering challenges on real-life case studies.
Students would not be allowed to leave until they had distilled the essence of the problem and come up with a potential approach to solving it on one sheet of paper. Peck said: "If you can't reduce a difficult engineering problem to just one 8.5 by 11 inch sheet of paper you will probably never understand it."
Internationally respected soil mechanic professor John Burland of Imperial College London said of him: "He was a brilliant educator whose great strength was teaching from case histories to distil the essence of a problem."
Ralph Brazleton Peck was an only child born 23 June 1912 in Winnipeg, Canada, to American parents Orwin K and Ethel Huyck Peck. His father was a civil engineer who was designing bridges for the Northern Pacific Railway in Canada when his son was born. The Peck family eventually settled in Denver, Colorado, where his father worked on the Rio Grande Western Railroad.
His father's all consuming passion for bridge engineering was catchy and Peck developed an early ambition to be an engineer. Peck graduated in civil engineering from Rensselaer Polytechnic Institute in Troy, New York, in 1934. After completing a doctorate in 1937, he started working as a bridge engineer in the state but was quickly laid off because there was not enough work for him.
This early professional misfortune proved the turning point of his life. Unemployed, Peck applied, and was accepted, to study a course at Harvard in the new subject of soil mechanics.
His big break followed soon after in 1939 when he was appointed to the Chicago subway project as an assistant to Terzaghi, with whom he co-authored Soil Mechanics in Engineering Practice in 1948 – still regarded as the industry bible.
For the next three years, Peck worked with the tireless Terzaghi, an experience that would prove invaluable in his later work on subway systems in Washington and San Francisco, the Trans-Alaskan Pipeline system, the James Bay Dam in Quebec, the stabilisation of the Dead Sea dikes and the strengthening of subsiding ground beneath the Leaning Tower of Pisa.
In 1974 his services to engineering were recognised when he was awarded a National Medal of Science by US President Gerald Ford. By now, retired to Albuquerque, New Mexico, he continued to be much in demand as a consultant. His final project, the Rion-Antiron Bridge in Greece, received the American Society of Civil Engineers' Outstanding Civil Engineering Award in 2005.
Peck was a colourful personality who actively encouraged his fellow engineers to defy the dull and diffident image their profession suffered from. "The intense technical nature of engineering can lead to a deficiency in an engineer's social, spiritual and cultural life, and an inability to communicate effectively," he said. "A deliberate effort to broaden interests and read widely is needed."
Most of the engineers he came into contact with could not help but respond positively to his human touch.
"He was an amazing communicator with a lively sense of humour, but he was also a very gentle, self-effacing person who was always interested in what you were doing," said professor Burland. "He was a really much-loved figure."
Peck died of congestive heart failure on 18 February in Albuquerque, New Mexico, aged 95. His wife Marjorie died in 1996. He is survived by his daughter Nancy and son James.