Prestress Losses and Development of Short-Term Data Acquisition System for Bridge Monitoring

The University Transportation Center at Utah State University sponsors research through the Federal Highway Administration’s University Transportation Center Program. The purpose of this research is to advance technology and expertise in transportation-related fields. This includes research on the best methods to design, monitor, and inspect bridges. When a vehicle drives over a bridge, each bridge girder carries a portion of the vehicle’s weight. This load causes strain in the bottom of the bridge girders. However, depending on where the vehicle is located on the bridge, some bridge girders carry a higher percentage of the vehicle’s load. This study investigated the amount of strain typical vehicles caused in the bottom of each girder as they travel across the bridge. This research also examined the maximum strains in the bridge girders due to vehicle loads, which is of interest in girder design. In order to resist these vehicle loads, the effective prestress must be accurately determined. This project also quantified the effective prestress in an exterior and interior girder. These measured prestress forces are compared with predicted values in accordance to AASHTO LRFD specifications.  This report is available online at https://www.ugpti.org/resources/reports/downloads/mpc19-387.pdf