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Reduction of vibrations
BOOK REVIEWS Computer methods and advances in geomechanics G. Beer, J. R. Booker and J. P. Carter (eds) Balkema, Rotterdam, 1991, £122, (3 volumes) ISBN (Set) 90-6191-189-3 The three volumes comprising this publication are the summarized proceedings of an international conference held at Cairns, Australia, in May 1991. Volumes 1 and 2 together run to almost 1700 pages, and contain 4 keynote papers, and 257 other papers, grouped into 15 themes. Volume 1 contains the keynote papers, and the 121 papers which make up themes 1 to 7: 1 CAD, Expert systems and software 2 Geotechnical engineering and applications 3 Experimental studies, testing and field instrumentation 4 Joints, localisation and structural materials 5 Slopes, stability and distinct element methods 6 Constitutive modelling 7 Dynamics and cyclic loading Volume 2 contains 136 papers on the themes of: 8
Earthquakes and geophysical applications 9 Back analysis, comparison of field measurements and predictions 10 Analytic, semi-analytic and boundary element methods 11 Numerical methods 12 Mining applications 13 Tunnels and underground openings 14 Environmental, resource and groundwater geomechanics 15 Flow problems Volume 3, which only became available recently, is an altogether slimmer volume (123 pages of papers), and contains 2 more of the keynote papers, and 14 'late' papers. Added to this are the list of participants in the conference, and a list of authors. It was surprising that it did not contain any discussion. The large number of papers, themes, subjects and approaches in this conference make it a difficult task for the reviewer to do justice to it all, and it would be misleading to suggest that it has been possible to read more than a selection of the papers in any depth. Nor, I suggest, is it possible for most readers to understand all of it. Out of the bits I understand, I am not sure that I agree with all of it! However, I have had access to the papers in this conference for over a year, and in
that time I have had several opportunities to sample them. It appears, rightly or wrongly, that the subject groups reflect an attempt on the part of the editors to categorize the submissions to a relatively open conference, rather than that there was a conscious effort to concentrate the subject matter of the conference into a fewer number of more tightly specified areas. As a result, some of the papers sit together uneasily within this artificially forced grouping. For a researcher who is already deeply involved in geotechnical theory and computation, the conference provides much interest in their specialist field, and an insight into alternative approaches and techniques. For this class of reader, the publication will be a valuable library resource. A major defect in the conference paper format is that it is often too short to do justice to the subject, and is used by the author(s) merely as a ticket to attend the conference. Inevitably, seminal works in a particular area are published in refereed journals, since these are more highly valued, for instance, in research rating exercises. This particular conference adds value by virtue of its breadth, and so counteracts the inevitable lack of depth in many of the contributions. There is a variable standard of presentation of the papers in this conference. They have obviously been prepared by their authors in camera-ready form. How strange, therefore, that since one of the world's commonest applications for computers is the layout of text (from word processing to desk top publishing) the authors in this conference have made so little use of it. I look forward to the day when papers are all submitted on disk, and are edited into a common format, making the role of editor more than just an honorary title. As a sampler of some of the more unusual papers on computer methods which the publication contains, and which have caught my eye, I have selected a small number of the papers for brief comment. Coulthard and Ciesielski (p 51) describe a computer system that helps you choose which computer program to use in analysing particular problems. The proper use of computers is to study computing! Priest et al. (p 107) describe a set of simulation and design programs used in the teaching of geotechnical engineering, and give the student response to the exercise. These exercises replace conventional laboratory based work. Good, soon we can all do geotechnical engineering without ever having to come into contact with the 'dirty stuff' - and as a
side effect, will never need to analyse a test result which does not conform to the theoretical ideal! Moore et al. (p 371) present one of the papers which start to use fractal principles to describe the semi-ordered chaos of a soil mass. Before I read this paper, I normally thought of fractals in terms of beautiful abstract art, or scenery in computer games. It is truly remarkable how readily the human mind perceives order in the truly random and chaotic. The fractal demonstrates that this underlying orderliness is not necessarily imaginary. Giani and Ferrerro (p 741) analyse the behaviour of sea and river walls under wave action. The particular walls considered date back to the eighteenth century. I often wonder how the engineers of years gone by actually coped without computers to rack up all those extra feeearning hours. None of the papers that I read addressed my own personal concern, which is that the sheer availability of power computers, and the commercial pressures on people writing software, lead to the dissemination of dangerous doubleedged weapons into the engineering community. To err is human, but for a downright disaster, you need a computer. Inevitably, the most benefit from a conference such as this is gained by the individuals who attended, particularly those who made the effort to write a paper, and as a result established contact with like-minded researchers in some faroff university with whom they could collaborate or compete as the fancy takes them. The reader of the proceedings misses that essential human interaction that makes a conference particularly valuable. I wish I had been there.
E. N. Bromhead
Reduction of vibrations G. B. Warburton, J. Wiley & Sons, Chichester, 1992, 91 pages, £ 17.50 This book contains the edited text of the third Mallet-Milne lecture, delivered by Professor Warburton in 1992 at the Institution of Civil Engineers. The biennial sequence of formal lectures intended to commemorate Robert Mallet and John Milne was initiated in 1987 by the British branch of the International Association of Earthquake Engineering. The first and second lecture in this series were given by N. N. Ambraseys and G. W. Housner, respectively. G. B. Warburton, Professor Emeritus at the University of Nottingham, is well
Eng. Struct. 1993, Volume 15, Number 5
395
Book reviews known in the international community of earthquake engineering, and in the broader community of structural engineering, and mechanics, because of his outstanding work as a researcher and research leader in structural dynamics and also because of his present role of General Editor of the journal Earthquake Engineerin 9 and Structural Dynamics. In this book Professor Warburton deals with the kinds of design provisions apt to reduce the dynamic response of a structure to earthquake excitation: additional damping devices, base isolation, tuned mass dampers (absorbers); active control systems. The four methods of vibration reduction are elucidated from their basic ideas to the practical implementations and their potentialities are comparatively discussed by means of applications to simple structural models. The presentation preserves the style of an excellent lecture: optimal compromise between the conflicting requirements of conciseness and clearness; abundant and well chosen visualization by neat graphs and photos, a tutorial approach with focus on essential aspects (with some more technical information relegated to appendices), carefully selected references to the available literature. This authoritative conspectus of the title subject is certainly of interest to
396
nonspecialists like this reviewer, because it provides an effective introduction to a timely research topic in applied mechanics. However, this volume is likely to appeal also to the experts as an up-todate state-of-the-art concerning an important and growing area of earthquake engineering and structural dynamics.
Giulio Maier
Experimental and numerical methods in earthquake engineering - reliability and risk analysis J. Donea and P. M. Jones (ed). Kluwer A cademic Publishers, Dordrecht, The Netherlands, 1991 ISBN: 0.7923. 1434.4 SUS 105.00 This book is a conglomeration of research papers presented during an advanced study seminar held at the Joint Research Center, Ispra Italy, 7-11 October 1991. The topics cover a wide spectrum from experimental testing of structures, both in field and laboratories to high tuned numerical investigations. Therefore, the book addresses itself
Eng. Struct. 1993, Volume 15, Number 5
primarily to academic researchers and high level designers, in my view, it can offer only limited benefit to ordinary undergraduate, and graduate students. It lacks coherence, integration and continuity because there are 14 chapters presented by some 22 different authors. The book is a paradise, however, for those who are interested in (1), understanding the influence of infill walls in seismic behaviour of concrete and steel frames; (2), discovering the free and forced vibration characteristics of a suspension bridge, of a rock fill dam or an arch dam, (3), exploring how the liquefaction failure, which is a menace for safe earthquake design, can be a magical tool for seismic base isolation, (4), eliminating a shaking table for the purpose of testing a structural model subject to a ground motion, by means of exerting horizontal displacements at the superstructure of the fixed base model. In each of these topics, extensive and most informative data are available through in situ and laboratory testing as well as through the finite element method of numerical analyses. For these highly advanced and upto-date topics of experimental research in earthquake engineering, the book is well worth keeping on our shelves.
Semih S. Tezcan
Earthquakes and geophysical applications 9 Back analysis, comparison of field measurements and predictions 10 Analytic, semi-analytic and boundary element methods 11 Numerical methods 12 Mining applications 13 Tunnels and underground openings 14 Environmental, resource and groundwater geomechanics 15 Flow problems Volume 3, which only became available recently, is an altogether slimmer volume (123 pages of papers), and contains 2 more of the keynote papers, and 14 'late' papers. Added to this are the list of participants in the conference, and a list of authors. It was surprising that it did not contain any discussion. The large number of papers, themes, subjects and approaches in this conference make it a difficult task for the reviewer to do justice to it all, and it would be misleading to suggest that it has been possible to read more than a selection of the papers in any depth. Nor, I suggest, is it possible for most readers to understand all of it. Out of the bits I understand, I am not sure that I agree with all of it! However, I have had access to the papers in this conference for over a year, and in
that time I have had several opportunities to sample them. It appears, rightly or wrongly, that the subject groups reflect an attempt on the part of the editors to categorize the submissions to a relatively open conference, rather than that there was a conscious effort to concentrate the subject matter of the conference into a fewer number of more tightly specified areas. As a result, some of the papers sit together uneasily within this artificially forced grouping. For a researcher who is already deeply involved in geotechnical theory and computation, the conference provides much interest in their specialist field, and an insight into alternative approaches and techniques. For this class of reader, the publication will be a valuable library resource. A major defect in the conference paper format is that it is often too short to do justice to the subject, and is used by the author(s) merely as a ticket to attend the conference. Inevitably, seminal works in a particular area are published in refereed journals, since these are more highly valued, for instance, in research rating exercises. This particular conference adds value by virtue of its breadth, and so counteracts the inevitable lack of depth in many of the contributions. There is a variable standard of presentation of the papers in this conference. They have obviously been prepared by their authors in camera-ready form. How strange, therefore, that since one of the world's commonest applications for computers is the layout of text (from word processing to desk top publishing) the authors in this conference have made so little use of it. I look forward to the day when papers are all submitted on disk, and are edited into a common format, making the role of editor more than just an honorary title. As a sampler of some of the more unusual papers on computer methods which the publication contains, and which have caught my eye, I have selected a small number of the papers for brief comment. Coulthard and Ciesielski (p 51) describe a computer system that helps you choose which computer program to use in analysing particular problems. The proper use of computers is to study computing! Priest et al. (p 107) describe a set of simulation and design programs used in the teaching of geotechnical engineering, and give the student response to the exercise. These exercises replace conventional laboratory based work. Good, soon we can all do geotechnical engineering without ever having to come into contact with the 'dirty stuff' - and as a
side effect, will never need to analyse a test result which does not conform to the theoretical ideal! Moore et al. (p 371) present one of the papers which start to use fractal principles to describe the semi-ordered chaos of a soil mass. Before I read this paper, I normally thought of fractals in terms of beautiful abstract art, or scenery in computer games. It is truly remarkable how readily the human mind perceives order in the truly random and chaotic. The fractal demonstrates that this underlying orderliness is not necessarily imaginary. Giani and Ferrerro (p 741) analyse the behaviour of sea and river walls under wave action. The particular walls considered date back to the eighteenth century. I often wonder how the engineers of years gone by actually coped without computers to rack up all those extra feeearning hours. None of the papers that I read addressed my own personal concern, which is that the sheer availability of power computers, and the commercial pressures on people writing software, lead to the dissemination of dangerous doubleedged weapons into the engineering community. To err is human, but for a downright disaster, you need a computer. Inevitably, the most benefit from a conference such as this is gained by the individuals who attended, particularly those who made the effort to write a paper, and as a result established contact with like-minded researchers in some faroff university with whom they could collaborate or compete as the fancy takes them. The reader of the proceedings misses that essential human interaction that makes a conference particularly valuable. I wish I had been there.
E. N. Bromhead
Reduction of vibrations G. B. Warburton, J. Wiley & Sons, Chichester, 1992, 91 pages, £ 17.50 This book contains the edited text of the third Mallet-Milne lecture, delivered by Professor Warburton in 1992 at the Institution of Civil Engineers. The biennial sequence of formal lectures intended to commemorate Robert Mallet and John Milne was initiated in 1987 by the British branch of the International Association of Earthquake Engineering. The first and second lecture in this series were given by N. N. Ambraseys and G. W. Housner, respectively. G. B. Warburton, Professor Emeritus at the University of Nottingham, is well
Eng. Struct. 1993, Volume 15, Number 5
395
Book reviews known in the international community of earthquake engineering, and in the broader community of structural engineering, and mechanics, because of his outstanding work as a researcher and research leader in structural dynamics and also because of his present role of General Editor of the journal Earthquake Engineerin 9 and Structural Dynamics. In this book Professor Warburton deals with the kinds of design provisions apt to reduce the dynamic response of a structure to earthquake excitation: additional damping devices, base isolation, tuned mass dampers (absorbers); active control systems. The four methods of vibration reduction are elucidated from their basic ideas to the practical implementations and their potentialities are comparatively discussed by means of applications to simple structural models. The presentation preserves the style of an excellent lecture: optimal compromise between the conflicting requirements of conciseness and clearness; abundant and well chosen visualization by neat graphs and photos, a tutorial approach with focus on essential aspects (with some more technical information relegated to appendices), carefully selected references to the available literature. This authoritative conspectus of the title subject is certainly of interest to
396
nonspecialists like this reviewer, because it provides an effective introduction to a timely research topic in applied mechanics. However, this volume is likely to appeal also to the experts as an up-todate state-of-the-art concerning an important and growing area of earthquake engineering and structural dynamics.
Giulio Maier
Experimental and numerical methods in earthquake engineering - reliability and risk analysis J. Donea and P. M. Jones (ed). Kluwer A cademic Publishers, Dordrecht, The Netherlands, 1991 ISBN: 0.7923. 1434.4 SUS 105.00 This book is a conglomeration of research papers presented during an advanced study seminar held at the Joint Research Center, Ispra Italy, 7-11 October 1991. The topics cover a wide spectrum from experimental testing of structures, both in field and laboratories to high tuned numerical investigations. Therefore, the book addresses itself
Eng. Struct. 1993, Volume 15, Number 5
primarily to academic researchers and high level designers, in my view, it can offer only limited benefit to ordinary undergraduate, and graduate students. It lacks coherence, integration and continuity because there are 14 chapters presented by some 22 different authors. The book is a paradise, however, for those who are interested in (1), understanding the influence of infill walls in seismic behaviour of concrete and steel frames; (2), discovering the free and forced vibration characteristics of a suspension bridge, of a rock fill dam or an arch dam, (3), exploring how the liquefaction failure, which is a menace for safe earthquake design, can be a magical tool for seismic base isolation, (4), eliminating a shaking table for the purpose of testing a structural model subject to a ground motion, by means of exerting horizontal displacements at the superstructure of the fixed base model. In each of these topics, extensive and most informative data are available through in situ and laboratory testing as well as through the finite element method of numerical analyses. For these highly advanced and upto-date topics of experimental research in earthquake engineering, the book is well worth keeping on our shelves.
Semih S. Tezcan