| The final goal of this research was to develop recommendations for the future seismic design or assessment of reinforced concrete (RC) bridge bent structures in cold seismic regions. Ten large scale circular columns were constructed and tested under cyclic reversal of loads inside an environmental chamber in the North Carolina State University Constructed Facilities Laboratory (CFL). The columns were tested at freezing (-°40C, -40°F) and ambient (23°C, 74°F) temperatures. In order to characterize every aspect of the seismic response at low temperatures, the columns' design was governed by a desire behavior. The columns tested can be classified in three different groups: (1) ordinary reinforced concrete (ORC) shear dominated columns, (2) ORC flexural dominated columns and (3) reinforced concrete filled steel tube (RCFST) flexural dominated columns.;Results obtained show that RC member exposed to the combined effect of sub-freezing temperatures and cyclic loads undergo a gradual increase in strength and stiffness coupled with a reduction in displacement capacity. The experimental results were used to calibrate a fiber-based model and a series of static and inelastic analyses were performed to typical Alaska DOT bent configurations. Based on the results obtained from the experimental tests, the non-linear simulations and a moment-curvature parametric analyses, a simple methodology was developed to account for the low temperature flexural overstrength and reduction in ductility capacity. |
