Effects of seasonal freezing on bridge column-foundation-soil interaction and their implications

Several seismic regions around the world experience seasonal freezing that can drastically alter the soil-foundation-structure interaction and structural response under earthquake loads. This paper analytically investigates the effects of seasonal freezing on lateral load response of a bridge column supported by a cast-in-drilled-hole (CIDH) foundation shaft. Accounting for the temperature effects on materials, the analyses were conducted at ambient temperatures of 23 degrees C, -1 degrees C, -7 degrees C, -10 degrees C, and -20 degrees C, and the results obtained at 23 degrees C and -10 degrees C were validated using experimental data. In comparison to the response at 23 degrees C, the response of the column-shaft system in the range of -1 degrees C to -20 degrees C exhibited 40%-188% increase in the effective elastic stiffness, 17%-63% reduction in the lateral displacement capacity, 0.54-0.82 in upward shift in the maximum moment location, 25%-30% increase in the column shear demand, and 25%-80% increase in shear and 19%-68% reduction in the length of the plastic region in the CIDH shaft.