Print this page Othmar Ammann and the Great Gray Bridge
J.M. Syken
Course Outline
In this course, we will examine the creation of one of the world’s most important bridges – the George Washington Bridge, spanning the Hudson River between Fort Lee, New Jersey and Washington Heights in upper Manhattan. Our review will include an overview of the design/construction process which allowed the bridge to be built in phases, starting with the original single (upper) deck in 1931, the filling-in of the center two lanes after WWII (in 1946) to help meet increasing capacity demands (increasing capacity by one-third) and, lastly, the addition of the lower level (1959-62) that increased the bridge’s capacity by 75% and linked it with new arterial highways on both sides of the river which were part of the new Interstate Highway System and local/regional road network expansion/improvements.
In particular, we will examine in great depth and detail the creation of the four main cables of the bridge including materials, methods, systems, infrastructure requirements, equipment etc. used by the John Roebling’s Sons Company to create this all-important structural component of the bridge. As well, we will examine in detail the “Hudson Challenge” which will include both late nineteenth and early twentieth century plans for a Hudson River bridge at locations in lower and/or mid-Manhattan. Special focus will be on the suspension bridge schemes of Gustav Lindenthal, master bridge designer. Tangential to this, we will examine the life and career of Othmar H. Ammann – the designer of the George Washington Bridge. This will include his complex relationship with Lindenthal and his early and later career as a prominent bridge engineer in his own right. The successful application of “Deflection Theory,” as applied to the GWB’s design, will be of considerable interest and importance.
This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.
Learning Objective
At the conclusion of this course, the student will:
- Understand/appreciate the efforts to “Conquer the Hudson” with a bridge allowing for a direct link with the continental and regional railroads whose termini were on the western (NJ) shore of the Hudson River;
- Understand/appreciate the suspension bridge designed by Gustav Lindenthal in the mid-1880s that was nearly built and why work was ceased;
- Understand/appreciate the advances in technology (i.e. electric traction) that made tunnels more efficient and practical for bringing passenger trains into Manhattan;
- Understand/appreciate the profound changes brought about by the rise to prominence of the car and truck by the 1920s and how that influenced the selection of both the design and location of the GWB;
- Understand/appreciate the 1920s design of a suspension bridge of gargantuan proportions designed and promoted by Gustav Lindenthal and why it was passed over in favor of a bridge with more modest cost, dimensions and location;
- Understand/appreciate the early career of O.H. Ammann and how it led to his selection as the designer of the GWB;
- Understand/appreciate the significance of Deflection Theory to the design of long-span suspension bridges, how it influenced the design of the GWB in particular, and future long-span suspension bridges, in general;
- Understand/appreciate the challenges faced in creating foundations for the two bridge towers – on land in Manhattan and “in the wet” on the NJ side via the use of a large cofferdam;
- Understand/appreciate the challenges of creating suitable anchorages on both sides of the river to resist the tremendous pull of the cables using a massive concrete block on the NY side and two rock tunnels on the NJ side;
- Understand/appreciate the creation of the two steel towers and the debate over encasing them in stone (as originally planned);
- Understand/appreciate the role of architect Cass Gilbert in the architectural treatment of the GWB;
- Understand/appreciate the creation of the parallel wire cables via aerial spinning and why this system was used in lieu of a eyebar chain system;
- Understand/appreciate the role of the John Roebling’s Sons Company in the creation of the bridge cables and other important components;
- Understand/appreciate the supplemental additions to the GWB including the filling in of the center two upper deck lanes (1946) and the addition of the lower level (1959-62);
- Understand/appreciate the arterial highway addition improvements associated with the addition of the lower level as well as additional infrastructure, structures; and
- Understand/appreciate the legacy of the GWB to the city and two states it serves and to suspension bridge design.
Intended Audience
This course is intended for architects, engineers and other design professionals.
Benefit to Attendees
The attendee/s will gain an intimate knowledge and insight into the background of one of the most important works of civil engineering of the 20th Century – the George Washington Bridge
Course Introduction
The course includes an in-depth PowerPoint presentation and the viewing a documentary film.
Course Content
In this course, you are required to view/study the following slideshow and the materials contained in the web pages:
Othmar Ammann and the Great Gray Bridge (printable handout in PDF, 14 MB, see Note A below for downloading instruction)
Othmar Ammann and the Great Gray Bridge (non-printable slideshow for screen-viewing only, 46 MB, see Note A below for downloading instruction)
Archival/Documentary Film:
TITLE: Building the George Washington Bridge
LINK: https://www.youtube.com/watch?v=XR5f9LnfwuU
DURATION: 43:03
TITLE: The Great Grey Bridge: The George Washington Bridge Under Construction, 1929
LINK: https://www.youtube.com/watch?v=cC25vzmjXSc
DURATION: 20:37
Note A: Please click on the above underlined hypertext to view, download or print the document for your study. Because of the large file size, we recommend that you first save the file to your computer by right-clicking the mouse and choosing "Save Target As ...", and then open the file in Adobe Acrobat Reader from your computer.
Course Summary
When the Brooklyn Bridge opened over the East River in 1883, it started people wondering when someone would get around to bridging the twice-as-wide Hudson River on the other side of the island. After all, for the sake of commerce alone it made a lot of sense since the railroads ended where the Hudson began, Why it took nearly fifty years to see the “Hudson Challenge” met is not easily understood. It wasn’t that the span was unconquerable by the technology of the day, but the imposition by both states on either side of the river (at different times) that navigation be unhindered by river piers meant one thing: it would have to be a suspension bridge. It appeared the North River Bridge Company’s gigantic eyebar chain bridge; designed by Gustav Lindenthal, would be built before the 19th Century closed. Indeed, the foundation stone was laid in June 1895. An economic downturn, poor foundation conditions and electric traction would doom the bridge to failure and all that’s left of it is the lonely stone, but Lindenthal wouldn’t give up on his dream of spanning the Hudson with a bridge of his own monumental design. By the 1920s, his plans got even grander; for a bridge (and associated infrastructure) costing an impractical $500 million serving both trains and vehicles on two levels. His protege – a brilliant Swiss engineer named Othmar Ammann, would realize his mentor was living in a world of self-delusion and set out to design a more practical bridge for vehicles only, adaptable to future needs and designed and built with modern materials, methods and systems thus allowing for a more efficient, cost effective and beautiful design. The result: the world’s busiest (and heaviest) bridge – the George Washington.
Related Links
For additional technical information related to this subject, please visit the following websites:
http://en.wikipedia.org/wiki/George_Washington_Bridge
http://en.wikipedia.org/wiki/Othmar_Ammann
http://archive.org/stream/jresv15n3p317/jresv15n3p317_A1b#page/n0/mode/2up
(testing results on steel columns for towers)
https://archive.org/details/CLN-37-G-3
(silent film ca. 1950 – drive over bridge and back)
https://www.youtube.com/watch?v=FuWM6-xOQCY
(Film: The world's Longest Bridges - 08:50)
https://www.youtube.com/watch?v=k9VCyHa1BEs
(film: Bridging the Big Apple - 08:26)
https://www.youtube.com/watch?v=g0WSPkdf1OE
(Film: World's Most Extreme Bridges - 52:06)
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
