AUTC project number: 510021
Zhaohui (Joey) Yang (UAA)
With recent seismic activity and earthquakes in Alaska and throughout the Pacific Rim, seismic design is becoming an increasingly important public safety concern for highway bridge designers. Hoping to generate knowledge that can improve the seismic design of highway bridges in Alaska, researchers from the University of Alaska plan to test a fixity depth approach and a lateral resistance (p-y) approach in seismic bridge design. Currently, the Alaska Department of Transportation and Public Facilities (ADOT&PF) utilizes soil lateral resistance in the seismic design of bridge pile foundations. Knowledge about lateral resistance of frozen soils, particularly seasonally frozen soils at shallow depths, will help improve pile foundation design in cold regions such as Alaska. Researchers Zhaohui Yang and Anthony Paris are conducting laboratory experiments to examine key mechanical parameters for the frozen soils used to construct the p-y curve for modeling frozen soils. Although there have been studies on the mechanical properties of frozen soils, existing studies were based on remolded, artificially frozen soil samples, which do not necessarily represent the soil in the field. How much impact these disturbances have on the frozen soil strength and stress-strain behavior is not clear. Additionally there is a lack of studies of the stress-strain behavior at small strains based on naturally frozen samples. Yang and Paris hope to fill this knowledge gap by providing key frozen soil parameters for typical Alaska soils. These key soil parameters, Yang and Paris claim, are needed for predicting the formation and location of plastic hinges, and internal loads in bridge pilings embedded in frozen soils during seismic loading. The team will use this developing knowledge to conduct a bridge design engineers workshop to discuss their findings and how to apply them in the seismic design of bridges.