This document summarizes research on using natural frequency to identify damage in a bridge model. The study used SAP 2000 software to analyze the natural frequencies of a Warren truss bridge model for both undamaged and damaged cases. Six mode shapes were considered for the bridge model with three different damage cases that reduced the diameter of structural members. The results showed natural frequencies decreased as member diameters decreased, indicating natural frequency can detect structural damage represented by reduced member sizes. The goal was to develop an effective method to identify structural deterioration by monitoring changes in natural frequency.