The Howe Truss was designed by William Howe in 1840. It used mostly wood in construction and was suitable for longer spans than the Pratt truss. Therefore, it became very popular and was considered one of the best designs for railroad bridges back in the day. Many Howe truss bridges exist in the North West United States, where wood is plentiful.

The Pratt Truss was designed by Thomas and Caleb Pratt in 1844. It became popular for railway bridges because it was able to have long spans. The Pratt has many variations, most with their own unique name. For instance, the Baltimore, Pennsylvania, and the Parker are all based off the Pratt.

The Warren Truss was patented by James Warren in 1848. It has been around a while. The Warren Truss uses equilateral triangles to spread out the loads on the bridge. This is opposed to the Neville Truss which used isosceles triangles. The equilateral triangles minimize the forces to only compression and tension. Interestingly, as a load (such as a car or train) moves across the bridge sometimes the forces for a member switch from compression to tension. This happens especially to the members near the center of the bridge.

I am always on the look out for good software to help design model bridges. My latest find, Dr. Software, is a series of programs that allow you to customize a design, put a load on it, and see what happens. Dr. Truss comes in 2D and 3D options. You can also get Dr. Beam, which allows you to word with a beam and not a truss

Today was our Science Olympiad regionals. Being busy all day, I didn’t get a chance to watch but two towers being tested. But there weren’t any terribly impressive ones there, mine being 8.6 grams, and the next 12.4. There was one major complication. Instead of being provided with sand to load our towers as the [...]

This is the absolute best video I have seen about building model bridges. Roy Coleman, the founder of the International Bridge Building Contest, gives a very informative presentation in this video. The presentation is over an hour long. He shows how to build a bridge from scratch. He is gearing his video towards the Chicago Regional Contest in particular. The concepts, however, apply to virtually all model bridge building projects. This is a great companion video to my 5 Steps to Building a Model Bridge ebook

Hey everybody once again it’s me, First Timer. I thought the one thing that would make this website even better would be some vocabulary on the parts of bridges. Here are a few terms that might help if you ever need to describe different aspects of a truss or bridge

This is the first in reviving my question and answer posts. When I receive a well asked question, I will answer it and post some of the dialogue here.

These two questions are dealing with making an elevated bridge, very similar to the Science Olympiad challenge.

Science Olympiad is bringing back the Bridge Building event in 2009, except in a modified form. The event for ’09 is Elevated Bridge, which will provide an interesting and refreshing challenge. The draft rules that soinc.org are very interesting and make for a good read. Check them out as the new bridge event looks to [...]

The K Truss design was a variant from the Parker truss design. The Parker, in turn, came from the Pratt truss. The idea of the K truss is to break up the vertical members into smaller sections. This is because the vertical members are in compression. The shorter a member is, the more in can resist buckling from compression.