Northern Arizona University
2021 Steel Bridge Capstone Team

Field Testing

A die was rolled and Load Case 2 was selected for testing. According to this scenario, the two distributed loads were placed 8' and 12' from the end of the bridge. The predicted capacity for this scenario was 4021 lbs with a deflection of 1.193 inches. The failure was predicted to occur at connection A2 on the end of the bridge due to block shear. Water containers were used to place load on the bridge until failure.

Bridge Loading Video

Test Results

The bridge held 6,188 lbs in the field test and deflected 5 inches. The failure type and location was consistent with the predictions. Connection A2 failed at the short end of the bridge. The load exceeded the predictions by 2,167 lbs. The deflection exceeded predictions by 3.8 inches. It was likely that the materials used had higher tensile strengths than specified, accounting for the higher loads carried. The modeling and calculations were also done with conservative values and assumptions, which also led the team to predict a lower failure point

Though the connection did not fail, the square tube member experienced block shear at the predicted location.

• Last Updated 4.27.2021