Field Monitoring of Soil-Structure Interaction in Semi-Integral Bridges

Despite the rise in popularity of jointless bridges, their behavior is still not well understood. By eliminating expansion joints at the ends of the deck, the abutment backfill is affected by daily loading cycles due to thermally induced strains, leading to earth pressure ratcheting and backfill settlement. This study presents three years of monitoring data of a semi-integral bridge in Texas. This bridge was instrumented using a combination of earth pressure cells, laser distance meters, and temperature sensors. In this study, the effect of temperature variations on the evolution of earth pressures acting on abutment walls is evaluated. Results indicate that it is generally during the cold months that comparatively high increases in earth pressures develop, which do not necessarily lead to a symmetric response between the two abutments. Additionally, stress ratcheting was found to lead to excessive deformations in the wingwalls and loss of aggregates for the conditions that corresponded to the abutments under investigation.