Seismic Performance and Design of Bridge Foundations in Liquefiable Ground with a Frozen Crust

INE/AUTC 12.3

Experimental Study on an Electrical Deicing Technology Utilizing Carbon Fiber Tape

INE/AUTC 12.2

Frozen Soil Lateral Resistance for the Seismic Design of Highway Bridge Foundations

INE/AUTC 12.3

Impact of Embedded Carbon Fiber Heating Panel on the Structural/Mechanical Performance of Roadway Pavement

INE/AUTC 12.3

Seasonally Frozen Soil Effects on the Seismic Performance of Highway Bridges

INE/AUTC 12.0

Effects of Permafrost and Seasonally Frozen Ground on the Seismic Response of Transportation Infrastructure Sites

INE/AUTC 11.0

A Simplified Nonlinear Method for a Laterally Loaded Pile in Sloping Ground

A simplified nonlinear method was proposed to evaluate lateral behavior of a pile located in or nearby a slope, based on the traditional p-y method. This method was validated with field test results of a steel pipe pile in clay and model tests of piles in sand slopes. The comparison indicated that the calculated horizontal displacement and bending moment of piles agree well with experimental results. Then, parametric studies were performed, and it shows that horizontal displacement, rotation, bending moment, and shear force increase along with increasing slope angles; the depth of maximum moment locates at about 1.6 D below ground surface for horizontal ground, while this value turns to be about 3.6 D and 5.6 D for sloping ground of 30° and 60°, respectively. The study clearly shows that slope angle has a significant effect on the deflection and lateral capacity of piles

Cyclic Shear Behavior of Frozen Cement-Treated Sand–Concrete Interface

The cyclic shear behavior of frozen cement-treated soil–concrete interfaces is critical for analyzing soil–structure interfaces and foundation design in cold regions and artificially frozen ground. The cyclic shear behavior of the interface between frozen cement-treated sand and structure is investigated in this paper at various normal stresses and temperatures. Experimental results include the variation of the peak shear stress, peak normal displacement, shear stiffness with the number of cycles, and the relationship between peak shear stress and smoothness under certain conditions. Peak shear stresses of warm frozen cement-treated sand and cold frozen cement-treated sand varied with cycle number. Additionally, the former is significantly larger than the latter in the stable phase. The peak normal displacement showed the same results, indicating that the ice crystals formed on the surface and the strength of the frozen cement-treated sand have significant differences at various temperatures. The study’s findings aid in understanding the complexities of the cyclic shear behavior of frozen cement-treated sand and structure interfaces and provide references on frozen cement-treated sand zones in practical engineering

Engineering site response analysis of Anchorage, Alaska using site amplifications and random vibration theory

Earthquake records collected at dense arrays of strong-motion stations are often utilized in microzonation studies to evaluate the changes in site response due to variability in site conditions across a region. These studies typically begin with calculating Fourier spectral amplification(s) and then transition to performing engineering site response analyses. It has proven difficult to utilize Fourier spectral amplification(s) to define the appropriate elastic response spectr(um)/(a) for a site or sites. This is because, first, the ground motions recorded at these strong-motion stations have lower intensity and hence do not show the nonlinear site effects observed during higher-intensity earthquakes and, second, Fourier and response spectral amplitudes measure different aspects of ground motions. The strong-motion stations in Anchorage, Alaska, have been recording earthquakes in the region for the last three decades. This study utilizes a database of 95 events from 2004 to 2019 to calculate Fourier spectral amplifications at 35 stations using the generalized inversion technique (GIT). Estimated response spectra have been evaluated at each site by applying those Fourier spectral amplifications to a response spectrum of a reference station through random vibration theory (RVT). Correction factors are also applied within the approach to account for nonlinear site effects. This RVT-based approach is tested using ground motions recorded during the MW 7.1 2018 Anchorage Earthquake, and close matches between measured and predicted response spectra are found. The method is then compared with site response analyses using a calibrated 1D equivalent linear (EQL) model of the Delaney Park Downhole Array site. Estimated spectra using the RVT-based approach are, finally, compared with those using Next Generation Attenuation Subduction (NGA-Sub) and NGA-West2 ground-motion models. The proposed method provides a coherent and straightforward way to use GIT-derived Fourier spectral amplifications to directly estimate site-specific response spectra, accounting for nonlinear site effects and without requiring engineering characterization of subsurface soil conditions