Forces in Wingwalls from Thermal Expansion of Skewed Semi-Integral Bridges

摘要

Jointless bridges, such as semi-integral and integral bridges, have become more popular in recent years because of their simplicity in the construction and the elimination of high costs related to joint maintenance. Prior research has shown that skewed semi-integral bridges tend to expand and rotate as the ambient air temperature increases through the season. As a result of the bridge movement, forces are generated and transferred to the wingwalls of the bridge. ODOT does not currently have a procedure to determine the forces generated in the wingwalls from the thermal expansion and rotation of skewed semi-integral bridges. In this study, two semi-integral bridges with skews were instrumented and monitored for behavior at the interface of the bridges diaphragm and wingwall. A parametric analysis was also performed to determine the effects of different spans and bridge lengths on he magnitude of the forces. Based on the field results from the study it is recommended for the design of the wingwalls turned to run nearly parallel with the longitudinal axis of skewed semi-integral bridges should include a 100 psi loading at the wingwall/diaphragm interface from the thermal expansion of the bridge. In addition, analytical evaluations showed that longer spans and higher skews than allowed by ODOTs BDM could be used. However, additional considerations for larger movements and stresses generated at the wingwall/diaphragm interface would need to be considered in designs. Finally, bearing retainers in diaphragms, if used, require adequate cover to avoid spalling of concrete.