About The pghbridges Project


Both majestic and dramatic, yet commonplace and ignored, bridges and their close cousins, tunnels, can be marvelous inspirations or simply taken for granted.

Both types of structures are used as metaphors: Bridges join different and separate people, ideas, points of view; Tunnels are a shortcut, a direct path, a way to cut through confusion and get straight to a conclusion.

For some, there is art and grace in a structure. Early on, builders were cautious as they experimented with new materials and forms. They used simpler materials: wood, stone and iron. They worked with smaller pieces, like those in the criss-crossing lattice of a truss. And this intricacy becomes a quaint, and often beautiful, vocabulary of its own.

As engineering advanced, materials improved and complex calculations were made easier by computers, the scale and daring of structures were enhanced. There was a time of "no small plans" when public works were seen as a measure of progress. The names of architects, engineers, commissioners and contractors are proudly displayed on bronze plaques or carved in stone.

Today, there is no less engineering effort. In fact, it is probably greater than ever. Much emphasis is placed on achieving the highest performance with the lowest cost and the fewest materials. Now there are standardized materials and standardized designs. Often, a bridge built in one location is indistinguishable from many others. There are very few builder plates, and often the only data available in the field are a few stencil numbers on the outside of a beam near one abutment.

As engineering has come to overshadow architecture, many people view these structures as just one more break in the scenery on the way to work. Bridges become the weave area of a busy highway, and tunnels are cursed as the bottleneck that causes a 15 minute drive to turn into an hour.

The most prized examples of these structures are those which maintain an interplay between the necessity of getting safely from one side to the other with the sense that there is something uplifting about doing so with style.


The project's author, Bruce S. Cridlebaugh, is a graphic designer and computer systems manager by profession -- two fields which are usually undertaken by two different types of people. The balancing of creativity and aesthetics with logic and structure is reflected in the author as well as the subject matter.

Always having a interest in architecture and engineering --and living in a city where bridges are prominent --an insatiable curiosity led to research about the various types of bridges. Very little could be found on the internet. As the answers were found, the results were gathered into the popular "Bridge Basics: Spotter's Guide to Bridge Design" and hundreds of other webpages to be shared worldwide. Since 1999, several thousand people per week have visited Allegheny County and Pittsburgh in a "virtual" way.

The project also represents a convergence of many interests. Architecture; engineering; history; tourism; outdoors; transportation by land, water and rail; and more. As such, the visitors are varied as well. It is typical to receive inquiries from students, educators, engineers, historians, librarians, rail and road enthusiasts, news and feature writers, geneologists, travelers -- locally and from around the world.

The pghbridges Project strives to present information in a format which is easily used and understandable by anyone, including those without a technical background. Yet the Project maintains a level of detail which is intended to extend its usefulness to all levels of interest. Research is not limited to commonly available sources; much of the data is gathered first-hand and is therefore not available elsewhere. Published as a website, the information is made available immediately, inexpensively and internationally. The combination of historical background with technical details demonstrates the interesting intertwining of icons: Pittsburgh and Bridges.


The information in this website was primarily gathered by visiting the various bridges and tunnels. A combination of on-site measurements, sketches, photos and notes. A great effort is made to provide accurate data, and where possible the information shown on builder plates is included. In some cases, due to the nature of a given location, private property, high traffic, and so on, estimates were made.

Books, magazines, newspapers, maps, and internet research also provide sources of information. Pages for most structures will have information sources noted, and there is a page which gives a list of the most important sources.

The first phase of compiling the list of structures involves careful reading of USGS topo maps and cross-referencing all possible crossings with other street maps, aerial photos and on-site fieldchecks. As structures and crossings are noted, they are added to the index page for its corresponding topo map location. These comprehensive listings may be accessed from the List By Location page.

The second phase, which is taking place concurrently, is to use the comprehensive index as a guide for fieldchecks and photo sessions. At this time, some listings may be added, revised or deleted.

This site is not affiliated with any official agency, so the data given is generally what is available to the general public. Submission of new or revised data is welcome. Please cite the source of your facts as it is hoped that this site will continue to grow in size and accuracy.

There is a link at the bottom of each page for submitting info about a structure.


The estimate of 2,000 bridges includes only those with a span of over 8 feet. There may be some included in this site which are shorter. Structures which are historic, architecturally interesting or unusual may also be included. In the interest of compiling an historical record, there may also be damaged or ruined structures.

Generally, any and all types of bridges or tunnels may be listed. Private bridges, especially those serving residences, are usually not listed unless they are special in some way. For instance, a bridge may be included which has been adopted by a private owner after abandonment by the original public entity.

Also, culverts are normally not included unless there is some other significance. In some instances, a building which crosses a stream or road may be listed.


With more than 2,000 bridges in Allegheny County, it is somewhat impractical and rather expensive to take conventional photographs of each structure. Using filmless digital photography, however, a collection of photos is being created.

There will be more emphasis placed on outstanding, historic, or endangered structures.

Submit info or inquiry - share some facts or ask a question.

Page created:
Last modified: 16-Jun-2008