J. A. L. Waddell -- Bridge Engineering

About this digital version

John Alexander Low Waddell considered the two-volume Bridge Engineering to be his (literary) masterpiece. It is a large and complex work, by his estimate nearly one million words in length. It incorporates much of the material covered by his earlier De Pontibus and much more. Waddell considered that the mastery of the material in Bridge Engineering and its sequel The Economics of Bridgework to be a most useful preparation for young engineers interested in making a career of the art and science of bridge design and construction.

Waddell covers the history of Bridge Engineering in considerable detail in the PREFACE to the work. This Preface is well worth reading for those who have an interest in technical publishing.

The present electronic version is based on the first edition published in 1916. The first volume was copied from an example of the fourth one thousand. The second volume, not yet digitized, will be based on an example of the first one thousand copies of that volume.

Bibliographic details of the originals used in this transcription are as follows:

Bridge Engineering / by J.A.L. Waddell. -- 1st ed. --

New York : John Wiley & Sons, Inc., 1916

The print copy of the work digitized is found in the collection of the Lichtenberger Engineering Library, The University of Iowa Libraries, and has the call number TG145.W2

Volume I was scanned in 1 bit monochrome using a Minolta model PS7000 face-up scanner by Ms. Kristin Baum of the Preservation Department, The University of Iowa Libraries.

The scan was made to produce a service print copy. The digital version was a byproduct of that work. The digital copy was initially in the form of a single large PDF file that had been set up to allow printing pages with the proper left and right margins.

Adobe Acrobat Pro was used to extract the image files. I saved these first as JPEG files then used Adobe Photoshop Elements 2 to reduce the images to centered GIF files optimized for the Web. A typical JPEG file was in excess of 30 MB for one page. The GIF files were more typically around 70 KB.

I prepared a page template in HTML, which Paul Soderdahl of the University of Iowa Libraries converted to an Active Server Page (ASP) file. This dynamic page provided a means of displaying the GIF images.

To create a navigation structure beyond the simple page-turner incorporated in the ASP template, I performed OCR on the Table of Contents, Index, and lists of tables and illustrations by means of Omnipage Pro 12. After manual correction and some editing, the ASCII text files were converted to HTML pages and links were inserted. These navigational documents follow the page numbering sequence of the original, which is continuous through both volumes except as noted below. To avoid dead links, the index and other files have been completed only to the end of Volume I (page 1064). When Volume II is digitized, the appropriate links will be activated.

To make the page-turning and indexing functions work correctly, I chose to retain the page numbers of the original as names for the GIF files. The preliminary pages, numbered in Roman numerals, were assigned Arabic numbers zero through minus 74 to allow easy page turning. Index entries did not refer to these preliminaries, so this did not cause a navigation problem.

There was, however, a problem with the index to Volume I. While this index, which covers both volumes, is identical in content to the index at the end of Volume II, the pagination represents a continuation of the Roman sequence used in the prelimnaries -- almost. The printer re-used some of the Roman numerals in the first sequence so there is an overlap. Because there was no satisfactory means of page-turning into this Volume I index, I have treated that file as a separate document accessed though navigation buttons. The index at the end of Volume II continues the Arabic numbers of that volume, so this will not be a problem in Volume II.

The extensive glossary from Volume II had previously been rearranged to remove the numerous "See" references, remove duplication, and embed illustrations that were referred to only by page references in the original. The full original image of the glossary will be reproduced with Volume II, but the rearranged version is linked to the electronic version of Bridge Engineering as a reference. I should add at this point that all the materials used for navigation purposes also appear in the regular sequences of pages as images of the originals except for the Volume I index as noted above.

One of the most pervasive apparent flaws in the copy was produced by page curvature that could not be fully compensated for by the software used in processing. A second problem, affecting continuous-tone photographs, was posed by the one-bit digitizing. I compensated for this to some extent by image manipulation in Photoshop Elements. The original print volume had been returned to its owner and was no longer available for rescanning, so this was the best available compromise.

A more significant problem arose with some detailed line drawings. The original was not always well printed. The digitizing process sometimes converted poorly inked lines into nearly unreadable masses. For this reason I made a number of enlargements of drawings and corrected this "noise." Fold-out and two-page drawings were merged in these enlargements into more accurate representations of the originals.

Any project of this type will have errors. If any are noticed, please let me know and I will correct them if possible.

Jeff Dodd

Assistant Engineering Librarian

Lichtenberger Engineering Library