There are many situations for which interaction between structure and ground has to be considered. This involves important interactions between specialist structural and geotechnical engineers. During his career the author has encountered profound differences in approach between structural and geotechnical engineers often leading to a lack of understanding and difficulties in communication. This paper explores these differences and the reasons for them.
The term modelling is used extensively. It is defined as the process of idealising a real-life project including its geometry, material properties and loading in order to make it amenable to analysis and hence assessment for fitness of purpose. It is demonstrated that traditional structural modelling is very different from geotechnical modelling.
In this paper extensive reference is made to Hambly’s three and four legged stool, termed by Heyman16 as ‘Hambly’s paradox’. Hambly used the simple example of a four-legged stool to show that structural design calculations are frequently wide of the mark when it comes to analysing real-world structures. It is concluded that concepts such as ductility and robustness underpin the success of both structural and geotechnical modelling and more explicit recognition of these is needed. Case histories are given where ductility has been utilised and where lack of ductility has led to failure. The importance of gaining a clear understanding of mechanisms of behaviour prior to detailed analysis is also illustrated by means of case histories.
Prof John Burland, CBE
DSc(Eng), FREng, FRS, FIStructE, FICE, FCGI
Emeritus Professor of Soil Mechanics,
Imperial College London