<p>Although single-gravity shaking table experiments (1-g STE)) provide significant benefits for simulating the dynamic response of pile-soil systems in laterally spreading deposits, scale effects and nonlinear behavior limit the direct applicability of model results to prototype predictions. To address this, large-scale 1-g STE were conducted on bridge-pile-group systems in liquefiable sloped strata, complemented by the development of a nonlinear finite element (FE) computational framework. Four scaling-up factors (SUF) were applied to upscale the test model. Through the integration of experimental and numerical results, the reliability of 1-g tests in capturing seismic demands across various scales was evaluated, while also revealing the influence of an overlying crust layer. The findings indicate that the test results generally capture the seismic response trends in different SUF scenarios but tend to underestimate demands in scenarios with larger SUF. The pile top and the pile near the liquefiable layer bottom are identified as vulnerable zones under lateral spreading. Furthermore, the presence of an overlying crust layer significantly alters the damage mode, shifting the pile damage position from the base of the liquefiable layer to the pile head. Finally, based on extensive analyses considering ground motion uncertainty, SUF-seismic demand relationships were established, and extrapolation coefficients were proposed. These relationships provide a basis for rationally interpreting 1-g STE results for prototype predictions.</p>