EA Books

Assessing Loads on Silos and Other Bulk Storage Structures: Research Applied to Practice, Em Prof Geoffrey Blight
2006 ISBN: 0415392373, 234 pages, $211

Geoff Blight has spent over 30 years researching and measuring the loads exerted on the walls of structures containing bulk solid materials.  This book represents his presentation of the principal outcomes of this work.  In the Forward the author acknowledges that since the book deals largely with the results of the research carried out by the author and his colleagues and graduate students, the book contains few references to other work.  Readers of the book should bear this in mind as, in some respects, the approaches adopted by Blight vary markedly from what may be regarded as ‘the norm’.  For example, Blight dismisses the concept of the ‘switch stress’ saying that it has not been measured in full scale silos, however, his technique for estimating wall loads appears to lack any resemblance to the loads existing in conical hoppers under ‘flow conditions’.   It is an estimation of these hopper loads which provide the best basis for predicting the flow (or operational) loads on feeders and gates.  The techniques Blight employs for his measurement of relevant bulk materials characteristics reflects his training as a geotechnical engineer and no mention is made of the significant range of alternative techniques and that have been developed and are employed around the world for making these and other more extensive handleability measurements.

A significant proportion of Blight’s work relates to field measurements on full scale structures. This collection of research outcomes is very valuable.  Any designer of silo structures should read the book to ensure that they have an appreciation of the possible interactions of the contained bulk solids and the containment structure they are designing.  These interactions, which Blight generally refers to as ‘secondary effects,’ are many and variable and in some instances are also very significant in magnitude. 

Since in many instances the loads measured by Blight on particular silos were significantly less than the loads estimated by the design codes, Blight is rather critical of the various design codes that exist around the world including the current Australian Standard AS3774-1996 ‘Loads on Bulk Solids Containers’ and the relatively new EN1991-4 ‘Eurocode 1- Actions on Structures, Part 4 – Silos and Tanks’.  The significant ‘secondary effects’ discussed (and measured) by Blight provides a very valid reason why design codes, which are trying to cover all eventualities, are often rather conservative in their estimations! 

Despite the rather unconventional approaches and conclusions of some of Blight’s research and also the fact that the book only concentrates on the work of Blight and his associates, this book is still very valuable. It highlights the often neglected issues of the interactions of the storage structure and the contained bulk solid.  Any designer of bulk solids structures, especially if new to the field, should read this work.  However,  it is suggested that the book should not convince the reader to regard design codes as being excessively conservative.  Instances of storage structures for bulk solids failing catastrophically are still being reported rather regularly!

Review by Em Prof Peter Arnold, Centre for Bulk Solids and Particulate Technologies,
Faculty of Engineering, University of Wollongong.

Assessing Loads on Silos and Other Bulk Storage Structures is available from EA Books, http://www.engineersmedia.com.au/bookshop

Dissertation Research and Writing for Construction Students
S.G. Naoum
2007, ISBN: 0750682647, 209pp, $61.50

This is a title from UK sources: the author is from a department of surveying, property and construction at London South Bank University. It is the second edition of what must be judged a very successful title. It has been reprinted nine times since first publication in 1998.

The scope of the subject matter is closely tied to the regulations that apply to the B.Sc and M.Sc degrees offered at the author’s institution.

The material is divided into three Parts, of two, three and four chapters respectively. There are ten chapters in all, plus five appendices. Part One discusses literature review methodology. There are some useful observations, though much of the content is subject-specific. Part Two is the core of the book: it is titled Research design and methodology. The only research tools discussed are the use of questionaires and personal interviews. I have no experience of the use of such methods as research tools. My comment is though that this is a very limiting choice. Part Three on analysis and presentation of results has some useful observations and advice to offer the reader.

My overall impression is that the reader is being lead along a path of observation and recording the workings of a very important industry, without too many, or even any, side glances. There is a degree of repetition of stock phrases and other elements in the presentation that I found distracting. In earlier times some of what is written might have been construed as ‘spoon feeding’. This feeling comes to a head in the brief, concluding chapter on supervision and assessment.

The Index is worth studying. There are about 600 items listed. But topics such as Innovation, New-anything, Future prospects etc are not there. The construction industry, world-wide, is in need of constant monitoring and renewal. But other titles will have to be consulted to further these aims.

Reviewed by Peter Lowe, Emeritus Professor of Civil Engineering, University of Auckland and an Honorary Professor of Civil Engineering, University of Sydney.

Dissertation Research and Writing for Construction Students  is available from EA Books, http://www.engineersmedia.com.au/bookshop

Construction Claims, 2nd edition
by Philip Davenport
2006, ISBN: 1862876088, 319pp, $66.00

Philip Davenport’s “Construction Claims” Second Edition is a tour de force of the significant issues informing modern construction law in Australia today. Mr Davenport drills deeply into the law and controversies surrounding claims in the construction industry in a very robust style of writing well illustrated by decided cases in the area. The author is obviously highly knowledgeable and experienced in construction law and has quite rightly recognized the need for clarity and precision in this area which has attracted large numbers of non-legal claims consultants, many of whom advance claims without due regard to or understanding of the basic legal principles on which construction claims must be based.

One particularly refreshing aspect of this book is that it brings a high level of rigor to the practise of preparing and evaluating construction claims which would benefit many practitioners in the construction industry. It also demystifies terms and claims which are commonly misunderstood and misused. For example, quantum meruit claims are clearly explained and the allowable circumstances of their use well illustrated. One of the most prolific construction claims, the claim for variations, is very skilfully covered in Chapter 5 although the discussion does become a little esoteric at times.

One distracting aspect of the book is that the author indulges himself in long discourses on what appear to be pet topics from time to time with the result that the reader can be diverted from the main thrust of the subject matter. For example, the 17 page discourse on the “Hudson formula” might well have been reduced by half or more, particularly as the book is expressed to be targeted at students for whom such an in depth analysis of that formula is more academic than practical.

On that point, the book suffers as a textbook in two ways. First, the author frequently expresses subjective opinions which ought not appear unqualified in a student text. For example, the author’s treatment of global claims is disparaging and somewhat confusing. It is reasonably well established that a global claim is a legal claim notwithstanding that it is a difficult claim to succeed upon. Frequently a contractor will have no option but to make a global claim and the law recognises this whilst also acknowledging the evidentiary difficulty such a claim necessarily involves. The author actually states that global claims have no place in the law!

Also, the author is obviously a strong supporter of the recent legislation throughout Australia and New Zealand providing security of payment to contractors. He argues the merits of the adjudication process at every available opportunity but sometimes at the expense of objectivity. For example, the author ascribes the Principal’s loss in the Contrax case at page 147 to the courts’ (erroneous, in the author’s view) allowance of adjudications of global claims rather than the operation of the legislation itself which, this reviewer submits with due respect, was the real cause of the Principal’s loss. This reviewer would prefer to have read a more balanced discussion of this legislation, weighing the benefits of the quick result against the limitation on natural justice accorded to principals within the adjudication process.

The second criticism for using this book as a text for students is the author’s critical references to legal practitioners and courts working in the area of construction. In this reviewer’s opinion, it does not assist a student’s understanding of the objective law if their source of instruction is dismissive or cynically critical of the very system from which the law is found.

Subject to those few criticisms, however, this book is a masterful treatment of the broad topic of construction claims and is recommended to practitioners in the area. However, students should approach the text with an open mind. The book would be improved as a textbook if the author clearly stated where he offers mere opinion as distinct from legal proposition.

Reviewed by Bill Blake, Clarke Kann Lawyers, Brisbane, QLD.

Construction Claims is available form EA Books http://www.engineersmedia.com.au/bookshop