Modern Structural Analysis – Modelling Process and Guidance

Foreword by Michael Dickson

This interesting book promotes a new way of looking at structural analysis. It suggests that the ability to work with the model (as distinct from the solution process) is a primary issue which should be formally addressed in practice and in education. The content is focussed on modelling issues and I know of no other text which does this so comprehensively.

The early chapters contain much advice necessary to help the reader establish how to formulate a numerical model which might be capable of simulating the performance of the actual structural system under investigation. The later chapters include a good outline of the issues involved in modelling of structures using finite elements. The two case studies given at the end of the book are a good device to put the excellent advice given in the earlier sections into some perspective for the reader.

I found it most useful to have in the same book a reminder of the theoretical basis of the full range of finite element types and a sound method as to how to employ analysis as a reflective tool towards a better understanding of structural behaviour.

The rigorous treatment for the process of validation of a model is most enlightening as is that outlined for verification of the results. After all, the iterative process of model validation and output verification are the main activities for gaining a true understanding of structural behaviour.

My own experience working with Buro Happold tells me that robust structural design requires the willingness to develop an understanding of structural behaviour with a questioning mind. In most consulting offices, current practice is to undertake this using finite element models of increasing complexity as understanding of the problem at hand grows. Iain MacLeod describes clearly how to build up this understanding using sensitivity analysis and simplified loadings to test validity against expectations from parallel calculation and modelling experiences. It is argued that risk will be reduced in practice if there is a rigorous analytical process that reflects the realities of current engineering practice in most offices.

Most structures are of a reasonably conventional type and use well tried framing systems. Substantial experience already exists on their likely performance so hand calculations based on structural theory can be done to initiate formulation of the model or to act as a check on the results. However, even advanced classical methods struggle to model the sophistication of load paths in redundant or non linear structures where individual stiffness, material response and definition of restraint determines structural performance. In this case I have found that comparison of the output of simplified analytical results with physical models very useful as an addition to classical calculation - as advocated in the second chapter..

The book is thus both a useful reference for the practitioner and a comprehensive learning guide for the student. It builds on the publication by the Institution of Structural Engineers ‘Guidelines for the Use of Computers for Engineering Calculation’ published in 2002. Its carefully constructed content successfully redresses the imbalance in risk between the finite element process based around generally determinate calculation output which has itself been derived from a possibly non-determinate understanding of the actual modelling process. In the Introduction, the author suggests that all structural engineers and all civil engineers who use structural analysis will find the contents of the book to be useful. I think that he is right.

Michael Dickson FIStructE

Director ,Design and Technology Board, Buro Happold

President, Institution of Structural Engineers 2005-06

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