Review of Inspection, Evaluation and Maintenance of Suspension Bridge, and Inspection, Evaluation and Maintenance of Suspension Bridges—Case Studies edited by Sreenivas Alampalli and William J. Moreau

Suspension bridges are without doubt among the most elegant structures in the field of civil engineering. This type of bridge is formed by a set of pure and graceful elements in which the contribution of each one to the whole structure is perfectly clear, not only to the expert but even to the man in the street. Suspension bridges, apart from being subjected to loads of different types (gravity, wind, earthquakes, tsunamis, etc.), are often placed in zones in which the environment is especially aggressive and meteorological conditions may be extreme. Due to their special conditions, their maintenance is of prime importance, since one simple local failure could put a bridge out of service and cause serious economic losses and inconvenience to the travelling public.

While it is true that in certain countries, fewer new engineering projects involving this type of bridge are now being undertaken, as has happened in the United States, in others they are still being constructed, as in South Korea, Norway, Japan, Turkey, and especially China.

In these two books, Sreenivas Alampalli and William J. Moreau provide a faithfully drawn picture of the work being done by the International Cable Supported Bridge Operators’ Association (ICSBOA). As both books contain contributions in the form of chapters from some of the world’s leading experts in suspension bridge maintenance, their contents are clearly essential reading for those who work in this field.

When various authors participate in writing a book, the reader often perceives a certain inconsistency among the different chapters, a trait that can be identified in a number of recent examples. However, both Alampalli and Moreau’s books are perfectly organized and the chapters are clearly arranged in a logical order, and thus both editors should be congratulated on their excellent job of coordinating the contributions of the different authors.

Both books are closely related; the first contains an introduction to the inspection, evaluation, and maintenance of suspension bridges and the second offers a series of case studies on bridge maintenance. While both are well worth reading, a few points of constructive criticism cam be mentioned, but should not be seen as detracting from the great work done by the editors and the authors of the different chapters. Firstly, the chapters do not all use the same system of units; since the authors are from a number of different countries and it is to be hoped that the readers will be from all over the world, it would have been better to have used the international system of units (SI), giving other equivalent forms in brackets. Also, in both books the references get different treatment from one chapter to another. In general, almost all the chapters provide a good number of references that will be helpful to those readers who want further information on a specific point, but there are also a few that give very few or even no references at all.

The first book deals with the main aspects to be considered in the inspection, evaluation, and maintenance of suspension bridges and is divided into 12 excellently compiled and easy-to-read chapters. Readers are likely to especially appreciate both the quantity and quality of figures and graphs that support the text.

The book starts off brilliantly with Chapter 1, which contains an excellent account of the evolution of suspension bridges throughout history, in which one cannot help but note the care and attention given by B. Yanev to its composition and layout. Like the rest of the book, this chapter is very well illustrated and the photos provided are well chosen. Section 1.11, which shows the lessons learned from a series of failures, is especially interesting.

In Chapter 2, K. Ogihara explains the general aspects of designing and building suspension bridges. This chapter is quite short but contains some interesting information. The first two chapters are thus a good introduction to the special peculiarities of the design and construction of suspension bridges.

Chapter 3 then enters on one of the book’s main topics, bridge inspection, and the recommendations provided by J. Lorentzson, Y. Chen, L. Hansen, P. MacDonagh, J. Myszczynski, and D. Paskova on the inspection protocols for the different elements will be found to be really useful, as will the photos provided by way of illustration.

In Chapter 4, B. Colford focuses on the evaluation of the main cables. Among other things, the methods of evaluating the cable strength are explained, as are the possible causes of deterioration and ways of preventing corrosion.

W. J. Moreau in Chapter 5 deals with one of the most expensive items of maintaining a suspension bridge: corrosion of the main cables. This chapter is in general well written and structured.

Chapter 6, written by D. G. Faust, M. Bulmer, B. Urbans, and D. Wilkinson, deals with the maintenance of cables and suspender ropes, progressing from their manufacture and assembly to their inspection, preservation strategies, and monitoring.

While the importance of dehumidifying the cables is emphasized in some chapters, in Chapter 7, K. Ogihara describes the experience of Japan in using this technique. In view of the results obtained, it is quite likely that cable dehumidification will be widely adopted in bridges all over the world as the best way to keep the cables free from corrosion.

In Chapter 8, W. J. Moreau describes his experience in maintaining cable band bolts. These components play a vital role in conserving bridge integrity as the loads are transmitted through them from the suspender ropes to the main cables. Although this chapter is quite short, it is compulsive reading and the photographs provided are the perfect accompaniment to the text.

R. Holcomb deals with some key aspects of maintaining anchorage enhancements in Chapter 9. Especially interesting is the survey he includes in the Appendix with questions to be answered by bridge owners.

In Chapter 10, S. Sloan, D. K. Cobourne, M. Guzman, and J. Wible describe a case study on the maintenance of the anchorages of the George Washington Bridge between New York City and New Jersey. Besides being well structured, this chapter offers some very interesting information, and is complemented by Chapter 7 of the second book, which will later be commented on in this review.

D. List and C. Cocksedge make an excellent contribution in Chapter 11 in their description of the most significant aspects of the rehabilitation of the Tamar Bridge in the United Kingdom and also underline the importance of supplementary cables in improving bridge safety. In this chapter, Section 11.8 provides information on the monitoring process carried out during the reconstruction, which is of special interest.

As suspension bridges have become icons and symbols in many cities, they could easily be marked down as targets for terrorist attacks. In Chapter 12, S. Alampalli and M. M. Ettouney give a good account of how this security risk can be managed by applying the methods set out in this chapter.

The second book is divided into 11 chapters that give detailed information on 11 different suspension bridges, some of which are quite famous and some less well-known. This book is the perfect companion to the first, which it complements and also goes further into the subject of bridge maintenance.

These chapters are all of great interest. They all begin with the bridge’s history, design, and construction, including numerous details and curious information that most readers may not have been aware of. All the chapters offer information that would normally only be available to bridge operators.

Certain chapters have very similar indexes (Chapters 3, 4, 6, 7, and 8), which seems to indicate a certain degree of collaboration among their authors as regards organization. All the others are differently organized and have different types of indexes. In view of the special characteristics of this second book, it seems surprising that the editors and authors did not agree on similar indexes and contents in all the chapters.

In some very well written early sections of Chapter 1, authors B. Yanev and B. Gill give a magnificent description of the history of the Manhattan Bridge, supported by a good number of references.

In Chapter 2, K. Ogihara describes the Akashi Kaikyo Bridge in Kobe, Japan. Although the section dealing with its maintenance is relatively brief in relation to the other chapters, enough information is provided to be able to understand the main tasks involved. As this has been one of the bridges that has received most attention in academic papers and conferences in recent years, it was somewhat surprising that the author did not provide any references at all.

J. Gibson’s contribution in Chapter 3 on Hong Kong’s Tsing Ma Bridge is sure to interest readers. The author has taken special care with its organization and gives quite a few references, which makes it a great chapter. Section 3.6 gives some really important facts on inspection planning.

In Chapter 4, K. A. Nielsen, L. Vincentsen, and F. Bormlund describe the case of the Storebælt East Suspension Bridge in Denmark. The index is similar to that of Chapter 3 and the information is given in a logical order.

Chapter 5, written by D. Coldford, which deals with the Forth Road Bridge, is well written, especially Section 5.2, which gives some interesting information. The introductory section differs a little from the other chapters and gives rather scanty information on the bridge’s history, design, and construction. Those readers who are not well acquainted with the Forth Road Bridge in Scotland would have preferred an introduction more similar to those provided in the other chapters.

J. Lorentzson, D. Paskova, M. Hedge, J. Zhang, and M. Qasim describe the Bronx-Whitestone Bridge in New York City in Chapter 6. As in Chapter 5, the introduction seems a little too short, although the chapter is well organized and the sections dealing with inspection, maintenance, rehabilitation, and evaluation give readers all the information they need.

The George Washington Bridge, also in New York City, is the subject of Chapter 7, written by S. Sloan and J. Wible. Sections 7.1, 7.2, 7.3 and 7.4, on the bridge’s history, design, cost and schedule, and construction, respectively, were particularly interesting. The photos provided are well chosen and interesting. However, the sections on inspection, maintenance and future plans (7.5, 7.6, and 7.7) seemed a little too short and could have offered further information. The interested reader can however make up for this lack by resorting to the first book and reading Chapter 10, in which Sloan and Wible also collaborated.

Chapter 8, one of the book’s more interesting contributions, written by A. Chowdhury, A. Chatzifoti, and J. Eppell, deals excellently with the Angus L. Macdonald Bridge in Nova Scotia, Canada. The chapter’s organization, composition and figures are of the highest quality.

W. J. Moreau writes about the Mid-Hudson Bridge in upstate New York in Chapter 9. Compared to the other chapters, the introduction is a little short on facts about the bridge’s history, design, and construction, although Section 9.10, on deck replacement and general supporting infrastructure, was especially interesting.

G. Xu was responsible for Chapter 10, on the Shantou Bay Suspension Bridge in Shantou, China. Its history, design, and construction are gone into in some depth, probably more than in any of the other chapters, and the remaining sections are well planned, so that the author can be said to have done a very good job indeed.

In Chapter 11, S. Alampalli gives us the benefit of his experience of the Kensington-Port Ewen Bridge in New York state. This chapter is well organized and provides some very good references.

Overall, reading and reviewing these two excellent books has been a pleasure. Access to such books compiled by some of the leading experts in the maintenance of suspension bridges is a great privilege.

Both books are suitable reading for civil engineers and engineering students or indeed, for anybody involved in general bridge maintenance, since many of the aspects dealt with can be applied to other types of bridge.

Although this reviewer has worked for many years in the evaluation, assessment, and maintenance of many different types of structures, so far this has not included the opportunity to work on a suspension bridge. As a professor and structural engineer, professional knowledge has been enriched and new aspects of bridge maintenance have been learned by reading these volumes.

To sum up, the high quality of these books is such that their acquisition is a must for university libraries and also of course for all those interested in bridge engineering. Again, congratulations to the editors and authors on their good work. All engineers dedicated to structural maintenance should be grateful for this initiative of the ICSBOA’s members.