Northern Arizona University Steel Bridge

Project Information

The final design is shown below. To see how the truss type was selected, please refer to the 'Design Alternatives' tab. To see a full plan set please refer to the 'Documents' tab. Each letter represents on the following images is a type of connection, with members named according to the connections they span between.

Project Hours

Below is a summary of the hours spent on the project. The intern category is a combination of all of the mentee hours as well as other help recieved. For a gantt chart, please see the 'Documents' tab.

Comptition Details

Below is a link the the offical Steel Bridge contest website, which includes contest rules and other information. Please see this link for the project constraints.
Please note that this link is to an outside website

Below is a link the the ASCE PSWC website, where we competed.
Please note that this link is to an outside website

Competition Results

The first part of competition involves building the bridge in under 45 minutes. We were able to do this with three minutes to spare and only minor penalties

Next, the judges inspect the bridge for dimensional violations. Our bridge had one dinmensional violation, in one location the rails were too close together. This caused another minor penalty.

After the bridge was moved to the loading area and secured, a lateral load test was performed. 50 pounds was applied horizantally using a pull scale attached to the center of the bridge. The judges were very suprised to see no lateral deflection.

Then came the fimal test, the vertical load test. Angle bars were placed on the decking of the bridge to see if it could hold the required 2400 pounds. The bridge was allowed 3 inches of deflection. Our bridge was able to hold 2100 out of the 2400 pounds before failure. While fabricating the bridge we were not able to keep everything straight due to the fact that we built it ourselves. This caused a connection on the top of the truss to be crooked. The misalignment caused an internal moment and eventually caused the bridge to break. If the members had been straight the bridge would have easily held the weight with minimal deflection.