Designing and retrofitting existing building structures in high seismic regions of the United States relies on approximate assumptions of the structure’s dynamic behavior, from which an appropriate design pseudo acceleration is determined. However, these assumptions are often overly conservative and do not accurately represent the dynamic behaviors of the structures. This research questions the validity of these overly conservative assumptions and their role in the design of a seismic retrofit through a comparison of the assumed dynamic behavior and the actual dynamic behaviors of two separate single-story building structures. Both of these structures had the same original building construction, but one of the structures has had a seismic retrofit. This contrast allowed direct comparisons between the dynamic behaviors of the two structures to determine the effectiveness of the seismic retrofit. Closed-form analytical approaches, numerical modeling, operational modal analysis, and experimental modal analysis were used to determine the dynamic behavior of both buildings. The Fast Fourier Transform signal processing method was chosen to process the collected time series data into the frequency domain, from which appropriate dominant natural frequencies were chosen based on their relative amplitude and confidence.
